Lichen

Annotated deducer.py

107:3fe37462e0f6
2016-10-17 Paul Boddie Track attribute assignment in attribute usage in order to restrict accessors. Changed the function type to be separate from all other types, preventing special __fn__ and __args__ attribute shadowing.
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#!/usr/bin/env python
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"""
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Deduce types for usage observations.
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Copyright (C) 2014, 2015, 2016 Paul Boddie <paul@boddie.org.uk>
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program.  If not, see <http://www.gnu.org/licenses/>.
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"""
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from common import first, get_assigned_attributes, \
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                   get_attrname_from_location, get_attrnames, \
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                   get_invoked_attributes, get_name_path, init_item, \
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                   sorted_output, CommonOutput
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from encoders import encode_attrnames, encode_access_location, \
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                     encode_constrained, encode_location, encode_usage, \
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                     get_kinds, test_for_kinds, test_for_type
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from errors import DeduceError
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from os.path import join
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from referencing import combine_types, is_single_class_type, separate_types, \
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                        Reference
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class Deducer(CommonOutput):
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    "Deduce types in a program."
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    def __init__(self, importer, output):
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        """
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        Initialise an instance using the given 'importer' that will perform
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        deductions on the program information, writing the results to the given
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        'output' directory.
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        """
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        self.importer = importer
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        self.output = output
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        # Descendants of classes.
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        self.descendants = {}
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        self.init_descendants()
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        self.init_special_attributes()
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        # Map locations to usage in order to determine specific types.
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        self.location_index = {}
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        # Map access locations to definition locations.
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        self.access_index = {}
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        # Map aliases to accesses that define them.
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        self.alias_index = {}
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        # Map constant accesses to redefined accesses.
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        self.const_accesses = {}
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        self.const_accesses_rev = {}
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        # Map usage observations to assigned attributes.
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        self.assigned_attrs = {}
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        # Map usage observations to objects.
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        self.attr_class_types = {}
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        self.attr_instance_types = {}
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        self.attr_module_types = {}
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        # Modified attributes from usage observations.
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        self.modified_attributes = {}
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        # Accesses that are assignments.
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        self.reference_assignments = set()
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        # Map locations to types, constrained indicators and attributes.
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        self.accessor_class_types = {}
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        self.accessor_instance_types = {}
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        self.accessor_module_types = {}
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        self.provider_class_types = {}
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        self.provider_instance_types = {}
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        self.provider_module_types = {}
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        self.accessor_constrained = set()
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        self.access_constrained = set()
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        self.referenced_attrs = {}
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        self.referenced_objects = {}
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        # Details of access operations.
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        self.access_plans = {}
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        # Accumulated information about accessors and providers.
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        self.accessor_general_class_types = {}
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        self.accessor_general_instance_types = {}
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        self.accessor_general_module_types = {}
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        self.accessor_all_types = {}
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        self.accessor_all_general_types = {}
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        self.provider_all_types = {}
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        self.accessor_guard_tests = {}
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        # Accumulated information about accessed attributes and
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        # access/attribute-specific accessor tests.
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        self.reference_all_attrs = {}
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        self.reference_all_attrtypes = {}
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        self.reference_all_accessor_types = {}
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        self.reference_all_accessor_general_types = {}
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        self.reference_test_types = {}
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        self.reference_test_accessor_type = {}
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        # The processing workflow itself.
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        self.init_usage_index()
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        self.init_accessors()
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        self.init_accesses()
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        self.init_aliases()
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        self.init_attr_type_indexes()
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        self.modify_mutated_attributes()
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        self.identify_references()
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        self.classify_accessors()
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        self.classify_accesses()
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        self.initialise_access_plans()
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    def to_output(self):
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        "Write the output files using deduction information."
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        self.check_output()
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        self.write_mutations()
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        self.write_accessors()
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        self.write_accesses()
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        self.write_access_plans()
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    def write_mutations(self):
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        """
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        Write mutation-related output in the following format:
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        qualified name " " original object type
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        Object type can be "<class>", "<function>" or "<var>".
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        """
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        f = open(join(self.output, "mutations"), "w")
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        try:
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            attrs = self.modified_attributes.items()
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            attrs.sort()
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            for attr, value in attrs:
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                print >>f, attr, value
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        finally:
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            f.close()
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    def write_accessors(self):
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        """
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        Write reference-related output in the following format for types:
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        location " " ( "constrained" | "deduced" ) " " attribute type " " most general type names " " number of specific types
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        Note that multiple lines can be given for each location, one for each
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        attribute type.
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        Locations have the following format:
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        qualified name of scope "." local name ":" name version
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        The attribute type can be "<class>", "<instance>", "<module>" or "<>",
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        where the latter indicates an absence of suitable references.
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        Type names indicate the type providing the attributes, being either a
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        class or module qualified name.
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        ----
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        A summary of accessor types is formatted as follows:
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        location " " ( "constrained" | "deduced" ) " " ( "specific" | "common" | "unguarded" ) " " most general type names " " number of specific types
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        This summary groups all attribute types (class, instance, module) into a
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        single line in order to determine the complexity of identifying an
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        accessor.
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        ----
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        References that cannot be supported by any types are written to a
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        warnings file in the following format:
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        location
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        ----
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        For each location where a guard would be asserted to guarantee the
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        nature of an object, the following format is employed:
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        location " " ( "specific" | "common" ) " " object kind " " object types
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        Object kind can be "<class>", "<instance>" or "<module>".
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        """
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        f_type_summary = open(join(self.output, "type_summary"), "w")
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        f_types = open(join(self.output, "types"), "w")
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        f_warnings = open(join(self.output, "type_warnings"), "w")
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        f_guards = open(join(self.output, "guards"), "w")
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        try:
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            locations = self.accessor_class_types.keys()
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            locations.sort()
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            for location in locations:
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                constrained = location in self.accessor_constrained
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                # Accessor information.
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                class_types = self.accessor_class_types[location]
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                instance_types = self.accessor_instance_types[location]
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                module_types = self.accessor_module_types[location]
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                general_class_types = self.accessor_general_class_types[location]
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                general_instance_types = self.accessor_general_instance_types[location]
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                general_module_types = self.accessor_general_module_types[location]
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                all_types = self.accessor_all_types[location]
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                all_general_types = self.accessor_all_general_types[location]
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                if class_types:
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                    print >>f_types, encode_location(location), encode_constrained(constrained), "<class>", \
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                        sorted_output(general_class_types), len(class_types)
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                if instance_types:
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                    print >>f_types, encode_location(location), encode_constrained(constrained), "<instance>", \
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                        sorted_output(general_instance_types), len(instance_types)
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                if module_types:
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                    print >>f_types, encode_location(location), encode_constrained(constrained), "<module>", \
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                        sorted_output(general_module_types), len(module_types)
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                if not all_types:
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                    print >>f_types, encode_location(location), "deduced", "<>", 0
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                    attrnames = list(self.location_index[location])
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                    attrnames.sort()
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                    print >>f_warnings, encode_location(location), "; ".join(map(encode_usage, attrnames))
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                guard_test = self.accessor_guard_tests.get(location)
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                # Write specific type guard details.
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                if guard_test and guard_test.startswith("specific"):
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                    print >>f_guards, encode_location(location), guard_test, \
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                        get_kinds(all_types)[0], \
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                        sorted_output(all_types)
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                # Write common type guard details.
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                elif guard_test and guard_test.startswith("common"):
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                    print >>f_guards, encode_location(location), guard_test, \
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                        get_kinds(all_general_types)[0], \
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                        sorted_output(all_general_types)
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                print >>f_type_summary, encode_location(location), encode_constrained(constrained), \
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                    guard_test or "unguarded", sorted_output(all_general_types), len(all_types)
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        finally:
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            f_type_summary.close()
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            f_types.close()
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            f_warnings.close()
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            f_guards.close()
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    def write_accesses(self):
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        """
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        Specific attribute output is produced in the following format:
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        location " " ( "constrained" | "deduced" ) " " attribute type " " attribute references
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        Note that multiple lines can be given for each location and attribute
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        name, one for each attribute type.
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        Locations have the following format:
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        qualified name of scope "." local name " " attribute name ":" access number
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        The attribute type can be "<class>", "<instance>", "<module>" or "<>",
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        where the latter indicates an absence of suitable references.
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        Attribute references have the following format:
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        object type ":" qualified name
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        Object type can be "<class>", "<function>" or "<var>".
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        ----
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        A summary of attributes is formatted as follows:
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        location " " attribute name " " ( "constrained" | "deduced" ) " " test " " attribute references
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        This summary groups all attribute types (class, instance, module) into a
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        single line in order to determine the complexity of each access.
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        Tests can be "validate", "specific", "untested", "guarded-validate" or "guarded-specific".
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        ----
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        For each access where a test would be asserted to guarantee the
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        nature of an attribute, the following formats are employed:
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        location " " attribute name " " "validate"
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        location " " attribute name " " "specific" " " attribute type " " object type
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        ----
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        References that cannot be supported by any types are written to a
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        warnings file in the following format:
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        location
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        """
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        f_attr_summary = open(join(self.output, "attribute_summary"), "w")
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        f_attrs = open(join(self.output, "attributes"), "w")
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        f_tests = open(join(self.output, "tests"), "w")
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        f_warnings = open(join(self.output, "attribute_warnings"), "w")
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        try:
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            locations = self.referenced_attrs.keys()
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            locations.sort()
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            for location in locations:
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                constrained = location in self.access_constrained
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                # Attribute information, both name-based and anonymous.
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                referenced_attrs = self.referenced_attrs[location]
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                if referenced_attrs:
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                    attrname = get_attrname_from_location(location)
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                    all_accessed_attrs = self.reference_all_attrs[location]
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                    for attrtype, attrs in self.get_referenced_attrs(location):
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                        print >>f_attrs, encode_access_location(location), encode_constrained(constrained), attrtype, sorted_output(attrs)
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                    test_type = self.reference_test_types.get(location)
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                    # Write the need to test at run time.
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                    if test_type == "validate":
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                        print >>f_tests, encode_access_location(location), test_type
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                    # Write any type checks for anonymous accesses.
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                    elif test_type and self.reference_test_accessor_type.get(location):
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                        print >>f_tests, encode_access_location(location), test_type, \
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                            sorted_output(all_accessed_attrs), \
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                            self.reference_test_accessor_type[location]
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                    print >>f_attr_summary, encode_access_location(location), encode_constrained(constrained), \
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                        test_type or "untested", sorted_output(all_accessed_attrs)
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                else:
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                    print >>f_warnings, encode_access_location(location)
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        finally:
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            f_attr_summary.close()
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            f_attrs.close()
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            f_tests.close()
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            f_warnings.close()
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    def write_access_plans(self):
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        """
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        Each attribute access is written out as a plan of the following form:
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        location " " name " " test " " test type " " base " " traversed attributes
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                 " " attributes to traverse " " context " " access method
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                 " " static attribute
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        """
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        f_attrs = open(join(self.output, "attribute_plans"), "w")
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        try:
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            locations = self.access_plans.keys()
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            locations.sort()
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            for location in locations:
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                name, test, test_type, base, traversed, traversal_modes, attrnames, \
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                    context, context_test, \
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                    first_method, final_method, attr = self.access_plans[location]
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                print >>f_attrs, encode_access_location(location), \
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                                 name, test, test_type or "{}", \
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                                 base or "{}", \
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                                 ".".join(traversed) or "{}", \
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                                 ".".join(traversal_modes) or "{}", \
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                                 ".".join(attrnames) or "{}", \
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                                 context, context_test, \
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                                 first_method, final_method, attr or "{}"
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        finally:
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            f_attrs.close()
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    def classify_accessors(self):
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        "For each program location, classify accessors."
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        # Where instance and module types are defined, class types are also
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        # defined. See: init_definition_details
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        locations = self.accessor_class_types.keys()
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        for location in locations:
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            constrained = location in self.accessor_constrained
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            # Provider information.
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            class_types = self.provider_class_types[location]
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            instance_types = self.provider_instance_types[location]
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            module_types = self.provider_module_types[location]
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            # Collect specific and general type information.
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            self.provider_all_types[location] = \
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                combine_types(class_types, instance_types, module_types)
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            # Accessor information.
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            class_types = self.accessor_class_types[location]
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            self.accessor_general_class_types[location] = \
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                general_class_types = self.get_most_general_class_types(class_types)
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            instance_types = self.accessor_instance_types[location]
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            self.accessor_general_instance_types[location] = \
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                general_instance_types = self.get_most_general_class_types(instance_types)
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            module_types = self.accessor_module_types[location]
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            self.accessor_general_module_types[location] = \
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                general_module_types = self.get_most_general_module_types(module_types)
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            # Collect specific and general type information.
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            self.accessor_all_types[location] = all_types = \
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                combine_types(class_types, instance_types, module_types)
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            self.accessor_all_general_types[location] = all_general_types = \
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                combine_types(general_class_types, general_instance_types, general_module_types)
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            # Record guard information.
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            if not constrained:
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                # Record specific type guard details.
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                if len(all_types) == 1:
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                    self.accessor_guard_tests[location] = test_for_type("specific", first(all_types))
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                elif is_single_class_type(all_types):
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                    self.accessor_guard_tests[location] = "specific-object"
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                # Record common type guard details.
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                elif len(all_general_types) == 1:
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                    self.accessor_guard_tests[location] = test_for_type("common", first(all_types))
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                elif is_single_class_type(all_general_types):
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                    self.accessor_guard_tests[location] = "common-object"
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                # Otherwise, no convenient guard can be defined.
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    def classify_accesses(self):
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        "For each program location, classify accesses."
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        # Attribute accesses use potentially different locations to those of
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        # accessors.
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        locations = self.referenced_attrs.keys()
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        for location in locations:
paul@44 494
            constrained = location in self.access_constrained
paul@44 495
paul@69 496
            # Combine type information from all accessors supplying the access.
paul@44 497
paul@44 498
            accessor_locations = self.get_accessors_for_access(location)
paul@44 499
paul@44 500
            all_provider_types = set()
paul@44 501
            all_accessor_types = set()
paul@44 502
            all_accessor_general_types = set()
paul@44 503
paul@44 504
            for accessor_location in accessor_locations:
paul@44 505
paul@44 506
                # Obtain the provider types for guard-related attribute access
paul@44 507
                # checks.
paul@44 508
paul@67 509
                all_provider_types.update(self.provider_all_types.get(accessor_location))
paul@67 510
paul@67 511
                # Obtain the accessor guard types (specific and general).
paul@67 512
paul@67 513
                all_accessor_types.update(self.accessor_all_types.get(accessor_location))
paul@67 514
                all_accessor_general_types.update(self.accessor_all_general_types.get(accessor_location))
paul@44 515
paul@70 516
            # Obtain basic properties of the types involved in the access.
paul@70 517
paul@70 518
            single_accessor_type = len(all_accessor_types) == 1
paul@70 519
            single_accessor_class_type = is_single_class_type(all_accessor_types)
paul@70 520
            single_accessor_general_type = len(all_accessor_general_types) == 1
paul@70 521
            single_accessor_general_class_type = is_single_class_type(all_accessor_general_types)
paul@70 522
paul@69 523
            # Determine whether the attribute access is guarded or not.
paul@44 524
paul@44 525
            guarded = (
paul@70 526
                single_accessor_type or single_accessor_class_type or
paul@70 527
                single_accessor_general_type or single_accessor_general_class_type
paul@44 528
                )
paul@44 529
paul@44 530
            if guarded:
paul@44 531
                (guard_class_types, guard_instance_types, guard_module_types,
paul@57 532
                    _function_types, _var_types) = separate_types(all_provider_types)
paul@44 533
paul@67 534
            self.reference_all_accessor_types[location] = all_accessor_types
paul@67 535
            self.reference_all_accessor_general_types[location] = all_accessor_general_types
paul@63 536
paul@44 537
            # Attribute information, both name-based and anonymous.
paul@44 538
paul@44 539
            referenced_attrs = self.referenced_attrs[location]
paul@44 540
paul@71 541
            if not referenced_attrs:
paul@87 542
                raise DeduceError, repr(location)
paul@71 543
paul@71 544
            # Record attribute information for each name used on the
paul@71 545
            # accessor.
paul@71 546
paul@71 547
            attrname = get_attrname_from_location(location)
paul@71 548
paul@71 549
            all_accessed_attrs = set()
paul@71 550
            all_providers = set()
paul@71 551
paul@71 552
            # Obtain provider and attribute details for this kind of
paul@71 553
            # object.
paul@71 554
paul@71 555
            for attrtype, object_type, attr in referenced_attrs:
paul@71 556
                all_accessed_attrs.add(attr)
paul@71 557
                all_providers.add(object_type)
paul@71 558
paul@71 559
            all_general_providers = self.get_most_general_types(all_providers)
paul@71 560
paul@71 561
            # Determine which attributes would be provided by the
paul@71 562
            # accessor types upheld by a guard.
paul@71 563
paul@71 564
            if guarded:
paul@71 565
                guard_attrs = set()
paul@71 566
                for _attrtype, object_type, attr in \
paul@71 567
                    self._identify_reference_attribute(attrname, guard_class_types, guard_instance_types, guard_module_types):
paul@71 568
                    guard_attrs.add(attr)
paul@71 569
            else:
paul@71 570
                guard_attrs = None
paul@71 571
paul@71 572
            self.reference_all_attrs[location] = all_accessed_attrs
paul@71 573
paul@71 574
            # Constrained accesses guarantee the nature of the accessor.
paul@71 575
            # However, there may still be many types involved.
paul@71 576
paul@71 577
            if constrained:
paul@71 578
                if single_accessor_type:
paul@71 579
                    self.reference_test_types[location] = test_for_type("constrained-specific", first(all_accessor_types))
paul@71 580
                elif single_accessor_class_type:
paul@71 581
                    self.reference_test_types[location] = "constrained-specific-object"
paul@71 582
                elif single_accessor_general_type:
paul@71 583
                    self.reference_test_types[location] = test_for_type("constrained-common", first(all_accessor_general_types))
paul@71 584
                elif single_accessor_general_class_type:
paul@71 585
                    self.reference_test_types[location] = "constrained-common-object"
paul@44 586
                else:
paul@71 587
                    self.reference_test_types[location] = "constrained-many"
paul@71 588
paul@71 589
            # Suitably guarded accesses, where the nature of the
paul@71 590
            # accessor can be guaranteed, do not require the attribute
paul@71 591
            # involved to be validated. Otherwise, for unguarded
paul@71 592
            # accesses, access-level tests are required.
paul@71 593
paul@71 594
            elif guarded and all_accessed_attrs.issubset(guard_attrs):
paul@71 595
                if single_accessor_type:
paul@71 596
                    self.reference_test_types[location] = test_for_type("guarded-specific", first(all_accessor_types))
paul@71 597
                elif single_accessor_class_type:
paul@71 598
                    self.reference_test_types[location] = "guarded-specific-object"
paul@71 599
                elif single_accessor_general_type:
paul@71 600
                    self.reference_test_types[location] = test_for_type("guarded-common", first(all_accessor_general_types))
paul@71 601
                elif single_accessor_general_class_type:
paul@71 602
                    self.reference_test_types[location] = "guarded-common-object"
paul@71 603
paul@71 604
            # Record the need to test the type of anonymous and
paul@71 605
            # unconstrained accessors.
paul@71 606
paul@71 607
            elif len(all_providers) == 1:
paul@71 608
                provider = first(all_providers)
paul@71 609
                if provider != '__builtins__.object':
paul@71 610
                    all_accessor_kinds = set(get_kinds(all_accessor_types))
paul@71 611
                    if len(all_accessor_kinds) == 1:
paul@71 612
                        test_type = test_for_kinds("specific", all_accessor_kinds)
paul@70 613
                    else:
paul@71 614
                        test_type = "specific-object"
paul@71 615
                    self.reference_test_types[location] = test_type
paul@77 616
                    self.reference_test_accessor_type[location] = provider
paul@71 617
paul@71 618
            elif len(all_general_providers) == 1:
paul@71 619
                provider = first(all_general_providers)
paul@71 620
                if provider != '__builtins__.object':
paul@71 621
                    all_accessor_kinds = set(get_kinds(all_accessor_general_types))
paul@71 622
                    if len(all_accessor_kinds) == 1:
paul@71 623
                        test_type = test_for_kinds("common", all_accessor_kinds)
paul@71 624
                    else:
paul@71 625
                        test_type = "common-object"
paul@71 626
                    self.reference_test_types[location] = test_type
paul@77 627
                    self.reference_test_accessor_type[location] = provider
paul@71 628
paul@71 629
            # Record the need to test the identity of the attribute.
paul@71 630
paul@71 631
            else:
paul@71 632
                self.reference_test_types[location] = "validate"
paul@44 633
paul@67 634
    def initialise_access_plans(self):
paul@67 635
paul@67 636
        "Define attribute access plans."
paul@67 637
paul@67 638
        for location in self.referenced_attrs.keys():
paul@76 639
            original_location = self.const_accesses_rev.get(location)
paul@76 640
            self.access_plans[original_location or location] = self.get_access_plan(location)
paul@67 641
paul@44 642
    def get_referenced_attrs(self, location):
paul@44 643
paul@44 644
        """
paul@44 645
        Return attributes referenced at the given access 'location' by the given
paul@44 646
        'attrname' as a list of (attribute type, attribute set) tuples.
paul@44 647
        """
paul@44 648
paul@69 649
        d = {}
paul@69 650
        for attrtype, objtype, attr in self.referenced_attrs[location]:
paul@69 651
            init_item(d, attrtype, set)
paul@69 652
            d[attrtype].add(attr)
paul@69 653
        l = d.items()
paul@69 654
        l.sort() # class, module, instance
paul@44 655
        return l
paul@44 656
paul@44 657
    # Initialisation methods.
paul@44 658
paul@44 659
    def init_descendants(self):
paul@44 660
paul@44 661
        "Identify descendants of each class."
paul@44 662
paul@44 663
        for name in self.importer.classes.keys():
paul@44 664
            self.get_descendants_for_class(name)
paul@44 665
paul@44 666
    def get_descendants_for_class(self, name):
paul@44 667
paul@44 668
        """
paul@44 669
        Use subclass information to deduce the descendants for the class of the
paul@44 670
        given 'name'.
paul@44 671
        """
paul@44 672
paul@44 673
        if not self.descendants.has_key(name):
paul@44 674
            descendants = set()
paul@44 675
paul@44 676
            for subclass in self.importer.subclasses[name]:
paul@44 677
                descendants.update(self.get_descendants_for_class(subclass))
paul@44 678
                descendants.add(subclass)
paul@44 679
paul@44 680
            self.descendants[name] = descendants
paul@44 681
paul@44 682
        return self.descendants[name]
paul@44 683
paul@44 684
    def init_special_attributes(self):
paul@44 685
paul@44 686
        "Add special attributes to the classes for inheritance-related tests."
paul@44 687
paul@44 688
        all_class_attrs = self.importer.all_class_attrs
paul@44 689
paul@44 690
        for name, descendants in self.descendants.items():
paul@44 691
            for descendant in descendants:
paul@44 692
                all_class_attrs[descendant]["#%s" % name] = name
paul@44 693
paul@44 694
        for name in all_class_attrs.keys():
paul@44 695
            all_class_attrs[name]["#%s" % name] = name
paul@44 696
paul@44 697
    def init_usage_index(self):
paul@44 698
paul@44 699
        """
paul@44 700
        Create indexes for module and function attribute usage and for anonymous
paul@44 701
        accesses.
paul@44 702
        """
paul@44 703
paul@44 704
        for module in self.importer.get_modules():
paul@44 705
            for path, assignments in module.attr_usage.items():
paul@44 706
                self.add_usage(assignments, path)
paul@44 707
paul@44 708
        for location, all_attrnames in self.importer.all_attr_accesses.items():
paul@44 709
            for attrnames in all_attrnames:
paul@44 710
                attrname = get_attrnames(attrnames)[-1]
paul@44 711
                access_location = (location, None, attrnames, 0)
paul@107 712
                self.add_usage_term(access_location, ((attrname, False, False),))
paul@44 713
paul@44 714
    def add_usage(self, assignments, path):
paul@44 715
paul@44 716
        """
paul@44 717
        Collect usage from the given 'assignments', adding 'path' details to
paul@44 718
        each record if specified. Add the usage to an index mapping to location
paul@44 719
        information, as well as to an index mapping locations to usages.
paul@44 720
        """
paul@44 721
paul@44 722
        for name, versions in assignments.items():
paul@44 723
            for i, usages in enumerate(versions):
paul@44 724
                location = (path, name, None, i)
paul@44 725
paul@88 726
                for usage in usages:
paul@88 727
                    self.add_usage_term(location, usage)
paul@88 728
paul@88 729
    def add_usage_term(self, location, usage):
paul@44 730
paul@44 731
        """
paul@88 732
        For 'location' and using 'usage' as a description of usage, record
paul@44 733
        in the usage index a mapping from the usage to 'location', and record in
paul@44 734
        the location index a mapping from 'location' to the usage.
paul@44 735
        """
paul@44 736
paul@44 737
        init_item(self.location_index, location, set)
paul@88 738
        self.location_index[location].add(usage)
paul@44 739
paul@44 740
    def init_accessors(self):
paul@44 741
paul@44 742
        "Create indexes for module and function accessor information."
paul@44 743
paul@44 744
        for module in self.importer.get_modules():
paul@44 745
            for path, all_accesses in module.attr_accessors.items():
paul@44 746
                self.add_accessors(all_accesses, path)
paul@44 747
paul@44 748
    def add_accessors(self, all_accesses, path):
paul@44 749
paul@44 750
        """
paul@44 751
        For attribute accesses described by the mapping of 'all_accesses' from
paul@44 752
        name details to accessor details, record the locations of the accessors
paul@44 753
        for each access.
paul@44 754
        """
paul@44 755
paul@44 756
        # Get details for each access combining the given name and attribute.
paul@44 757
paul@44 758
        for (name, attrnames), accesses in all_accesses.items():
paul@44 759
paul@44 760
            # Obtain the usage details using the access information.
paul@44 761
paul@44 762
            for access_number, versions in enumerate(accesses):
paul@44 763
                access_location = (path, name, attrnames, access_number)
paul@44 764
                locations = []
paul@44 765
paul@44 766
                for version in versions:
paul@44 767
                    location = (path, name, None, version)
paul@44 768
                    locations.append(location)
paul@44 769
paul@44 770
                self.access_index[access_location] = locations
paul@44 771
paul@44 772
    def get_accessors_for_access(self, access_location):
paul@44 773
paul@44 774
        "Find a definition providing accessor details, if necessary."
paul@44 775
paul@44 776
        try:
paul@44 777
            return self.access_index[access_location]
paul@44 778
        except KeyError:
paul@44 779
            return [access_location]
paul@44 780
paul@44 781
    def init_accesses(self):
paul@44 782
paul@44 783
        """
paul@44 784
        Initialise collections for accesses involving assignments.
paul@44 785
        """
paul@44 786
paul@44 787
        # For each scope, obtain access details.
paul@44 788
paul@44 789
        for path, all_accesses in self.importer.all_attr_access_modifiers.items():
paul@44 790
paul@44 791
            # For each combination of name and attribute names, obtain
paul@44 792
            # applicable modifiers.
paul@44 793
paul@44 794
            for (name, attrnames), modifiers in all_accesses.items():
paul@44 795
paul@44 796
                # For each access, determine the name versions affected by
paul@44 797
                # assignments.
paul@44 798
paul@44 799
                for access_number, assignment in enumerate(modifiers):
paul@44 800
                    if name:
paul@44 801
                        access_location = (path, name, attrnames, access_number)
paul@44 802
                    else:
paul@44 803
                        access_location = (path, None, attrnames, 0)
paul@44 804
paul@71 805
                    if assignment:
paul@71 806
                        self.reference_assignments.add(access_location)
paul@71 807
paul@44 808
                    # Associate assignments with usage.
paul@44 809
paul@44 810
                    accessor_locations = self.get_accessors_for_access(access_location)
paul@44 811
paul@44 812
                    for location in accessor_locations:
paul@44 813
                        for usage in self.location_index[location]:
paul@44 814
                            if assignment:
paul@88 815
                                init_item(self.assigned_attrs, usage, set)
paul@88 816
                                self.assigned_attrs[usage].add((path, name, attrnames))
paul@44 817
paul@44 818
    def init_aliases(self):
paul@44 819
paul@44 820
        "Expand aliases so that alias-based accesses can be resolved."
paul@44 821
paul@44 822
        # Get aliased names with details of their accesses.
paul@44 823
paul@44 824
        for name_path, all_aliases in self.importer.all_aliased_names.items():
paul@44 825
            path, name = name_path.rsplit(".", 1)
paul@44 826
paul@44 827
            # For each version of the name, obtain the access location.
paul@44 828
paul@44 829
            for version, (original_name, attrnames, access_number) in all_aliases.items():
paul@44 830
                accessor_location = (path, name, None, version)
paul@44 831
                access_location = (path, original_name, attrnames, access_number)
paul@44 832
                init_item(self.alias_index, accessor_location, list)
paul@44 833
                self.alias_index[accessor_location].append(access_location)
paul@44 834
paul@44 835
        # Get aliases in terms of non-aliases and accesses.
paul@44 836
paul@44 837
        for accessor_location, access_locations in self.alias_index.items():
paul@44 838
            self.update_aliases(accessor_location, access_locations)
paul@44 839
paul@44 840
    def update_aliases(self, accessor_location, access_locations, visited=None):
paul@44 841
paul@44 842
        """
paul@44 843
        Update the given 'accessor_location' defining an alias, update
paul@44 844
        'access_locations' to refer to non-aliases, following name references
paul@44 845
        via the access index.
paul@44 846
paul@44 847
        If 'visited' is specified, it contains a set of accessor locations (and
paul@44 848
        thus keys to the alias index) that are currently being defined.
paul@44 849
        """
paul@44 850
paul@44 851
        if visited is None:
paul@44 852
            visited = set()
paul@44 853
paul@44 854
        updated_locations = set()
paul@44 855
paul@44 856
        for access_location in access_locations:
paul@44 857
            (path, original_name, attrnames, access_number) = access_location
paul@44 858
paul@44 859
            # Where an alias refers to a name access, obtain the original name
paul@44 860
            # version details.
paul@44 861
paul@44 862
            if attrnames is None:
paul@44 863
paul@44 864
                # For each name version, attempt to determine any accesses that
paul@44 865
                # initialise the name.
paul@44 866
paul@44 867
                for name_accessor_location in self.access_index[access_location]:
paul@44 868
paul@44 869
                    # Already-visited aliases do not contribute details.
paul@44 870
paul@44 871
                    if name_accessor_location in visited:
paul@44 872
                        continue
paul@44 873
paul@44 874
                    visited.add(name_accessor_location)
paul@44 875
paul@44 876
                    name_access_locations = self.alias_index.get(name_accessor_location)
paul@44 877
                    if name_access_locations:
paul@44 878
                        updated_locations.update(self.update_aliases(name_accessor_location, name_access_locations, visited))
paul@44 879
                    else:
paul@44 880
                        updated_locations.add(name_accessor_location)
paul@44 881
paul@44 882
            # Otherwise, record the access details.
paul@44 883
paul@44 884
            else:
paul@44 885
                updated_locations.add(access_location)
paul@44 886
paul@44 887
        self.alias_index[accessor_location] = updated_locations
paul@44 888
        return updated_locations
paul@44 889
paul@44 890
    # Attribute mutation for types.
paul@44 891
paul@44 892
    def modify_mutated_attributes(self):
paul@44 893
paul@44 894
        "Identify known, mutated attributes and change their state."
paul@44 895
paul@44 896
        # Usage-based accesses.
paul@44 897
paul@44 898
        for usage, all_attrnames in self.assigned_attrs.items():
paul@44 899
            if not usage:
paul@44 900
                continue
paul@44 901
paul@44 902
            for path, name, attrnames in all_attrnames:
paul@44 903
                class_types = self.get_class_types_for_usage(usage)
paul@44 904
                only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types)
paul@44 905
                module_types = self.get_module_types_for_usage(usage)
paul@44 906
paul@44 907
                # Detect self usage within methods in order to narrow the scope
paul@44 908
                # of the mutation.
paul@44 909
paul@44 910
                t = name == "self" and self.constrain_self_reference(path, class_types, only_instance_types)
paul@44 911
                if t:
paul@44 912
                    class_types, only_instance_types, module_types, constrained = t
paul@44 913
                objects = set(class_types).union(only_instance_types).union(module_types)
paul@44 914
paul@44 915
                self.mutate_attribute(objects, attrnames)
paul@44 916
paul@44 917
    def mutate_attribute(self, objects, attrnames):
paul@44 918
paul@44 919
        "Mutate static 'objects' with the given 'attrnames'."
paul@44 920
paul@44 921
        for name in objects:
paul@44 922
            attr = "%s.%s" % (name, attrnames)
paul@44 923
            value = self.importer.get_object(attr)
paul@44 924
paul@44 925
            # If the value is None, the attribute is
paul@44 926
            # inherited and need not be set explicitly on
paul@44 927
            # the class concerned.
paul@44 928
paul@44 929
            if value:
paul@44 930
                self.modified_attributes[attr] = value
paul@44 931
                self.importer.set_object(attr, value.as_var())
paul@44 932
paul@44 933
    # Simplification of types.
paul@44 934
paul@69 935
    def get_most_general_types(self, types):
paul@69 936
paul@69 937
        "Return the most general types for the given 'types'."
paul@69 938
paul@69 939
        module_types = set()
paul@69 940
        class_types = set()
paul@69 941
paul@69 942
        for type in types:
paul@69 943
            ref = self.importer.identify(type)
paul@69 944
            if ref.has_kind("<module>"):
paul@69 945
                module_types.add(type)
paul@69 946
            else:
paul@69 947
                class_types.add(type)
paul@69 948
paul@69 949
        types = set(self.get_most_general_module_types(module_types))
paul@69 950
        types.update(self.get_most_general_class_types(class_types))
paul@69 951
        return types
paul@69 952
paul@69 953
    def get_most_general_class_types(self, class_types):
paul@44 954
paul@44 955
        "Return the most general types for the given 'class_types'."
paul@44 956
paul@44 957
        class_types = set(class_types)
paul@44 958
        to_remove = set()
paul@44 959
paul@44 960
        for class_type in class_types:
paul@44 961
            for base in self.importer.classes[class_type]:
paul@44 962
                base = base.get_origin()
paul@44 963
                descendants = self.descendants[base]
paul@44 964
                if base in class_types and descendants.issubset(class_types):
paul@44 965
                    to_remove.update(descendants)
paul@44 966
paul@44 967
        class_types.difference_update(to_remove)
paul@44 968
        return class_types
paul@44 969
paul@44 970
    def get_most_general_module_types(self, module_types):
paul@44 971
paul@44 972
        "Return the most general type for the given 'module_types'."
paul@44 973
paul@44 974
        # Where all modules are provided, an object would provide the same
paul@44 975
        # attributes.
paul@44 976
paul@44 977
        if len(module_types) == len(self.importer.modules):
paul@44 978
            return ["__builtins__.object"]
paul@44 979
        else:
paul@44 980
            return module_types
paul@44 981
paul@44 982
    # More efficient usage-to-type indexing and retrieval.
paul@44 983
paul@44 984
    def init_attr_type_indexes(self):
paul@44 985
paul@44 986
        "Identify the types that can support each attribute name."
paul@44 987
paul@44 988
        self._init_attr_type_index(self.attr_class_types, self.importer.all_class_attrs)
paul@107 989
        self._init_attr_type_index(self.attr_instance_types, self.importer.all_instance_attrs, True)
paul@107 990
        self._init_attr_type_index(self.attr_instance_types, self.importer.all_combined_attrs, False)
paul@44 991
        self._init_attr_type_index(self.attr_module_types, self.importer.all_module_attrs)
paul@44 992
paul@107 993
    def _init_attr_type_index(self, attr_types, attrs, assignment=None):
paul@44 994
paul@44 995
        """
paul@44 996
        Initialise the 'attr_types' attribute-to-types mapping using the given
paul@44 997
        'attrs' type-to-attributes mapping.
paul@44 998
        """
paul@44 999
paul@44 1000
        for name, attrnames in attrs.items():
paul@44 1001
            for attrname in attrnames:
paul@107 1002
paul@107 1003
                # Permit general access for certain kinds of object.
paul@107 1004
paul@107 1005
                if assignment is None:
paul@107 1006
                    init_item(attr_types, (attrname, False), set)
paul@107 1007
                    init_item(attr_types, (attrname, True), set)
paul@107 1008
                    attr_types[(attrname, False)].add(name)
paul@107 1009
                    attr_types[(attrname, True)].add(name)
paul@107 1010
paul@107 1011
                # Restrict attribute assignment for instances.
paul@107 1012
paul@107 1013
                else:
paul@107 1014
                    init_item(attr_types, (attrname, assignment), set)
paul@107 1015
                    attr_types[(attrname, assignment)].add(name)
paul@44 1016
paul@88 1017
    def get_class_types_for_usage(self, usage):
paul@88 1018
paul@88 1019
        "Return names of classes supporting the given 'usage'."
paul@88 1020
paul@88 1021
        return self._get_types_for_usage(usage, self.attr_class_types, self.importer.all_class_attrs)
paul@88 1022
paul@88 1023
    def get_instance_types_for_usage(self, usage):
paul@44 1024
paul@44 1025
        """
paul@88 1026
        Return names of classes whose instances support the given 'usage'
paul@44 1027
        (as either class or instance attributes).
paul@44 1028
        """
paul@44 1029
paul@88 1030
        return self._get_types_for_usage(usage, self.attr_instance_types, self.importer.all_combined_attrs)
paul@88 1031
paul@88 1032
    def get_module_types_for_usage(self, usage):
paul@88 1033
paul@88 1034
        "Return names of modules supporting the given 'usage'."
paul@88 1035
paul@88 1036
        return self._get_types_for_usage(usage, self.attr_module_types, self.importer.all_module_attrs)
paul@88 1037
paul@88 1038
    def _get_types_for_usage(self, usage, attr_types, attrs):
paul@44 1039
paul@44 1040
        """
paul@88 1041
        For the given 'usage' representing attribute usage, return types
paul@44 1042
        recorded in the 'attr_types' attribute-to-types mapping that support
paul@44 1043
        such usage, with the given 'attrs' type-to-attributes mapping used to
paul@44 1044
        quickly assess whether a type supports all of the stated attributes.
paul@44 1045
        """
paul@44 1046
paul@44 1047
        # Where no attributes are used, any type would be acceptable.
paul@44 1048
paul@88 1049
        if not usage:
paul@44 1050
            return attrs.keys()
paul@44 1051
paul@107 1052
        keys = []
paul@107 1053
        for attrname, invocation, assignment in usage:
paul@107 1054
            keys.append((attrname, assignment))
paul@107 1055
paul@107 1056
        # Obtain types supporting the first (attribute name, assignment) key...
paul@107 1057
paul@107 1058
        types = set(attr_types.get(keys[0]) or [])
paul@107 1059
paul@107 1060
        for key in keys[1:]:
paul@107 1061
            
paul@44 1062
            # Record types that support all of the other attributes as well.
paul@44 1063
paul@107 1064
            types.intersection_update(attr_types.get(key) or [])
paul@44 1065
paul@44 1066
        return types
paul@44 1067
paul@44 1068
    # Reference identification.
paul@44 1069
paul@44 1070
    def identify_references(self):
paul@44 1071
paul@44 1072
        "Identify references using usage and name reference information."
paul@44 1073
paul@44 1074
        # Names with associated attribute usage.
paul@44 1075
paul@44 1076
        for location, usages in self.location_index.items():
paul@44 1077
paul@44 1078
            # Obtain attribute usage associated with a name, deducing the nature
paul@44 1079
            # of the name. Obtain types only for branches involving attribute
paul@44 1080
            # usage. (In the absence of usage, any type could be involved, but
paul@44 1081
            # then no accesses exist to require knowledge of the type.)
paul@44 1082
paul@44 1083
            have_usage = False
paul@44 1084
            have_no_usage_branch = False
paul@44 1085
paul@44 1086
            for usage in usages:
paul@44 1087
                if not usage:
paul@44 1088
                    have_no_usage_branch = True
paul@44 1089
                    continue
paul@44 1090
                elif not have_usage:
paul@44 1091
                    self.init_definition_details(location)
paul@44 1092
                    have_usage = True
paul@44 1093
                self.record_types_for_usage(location, usage)
paul@44 1094
paul@44 1095
            # Where some usage occurs, but where branches without usage also
paul@44 1096
            # occur, record the types for those branches anyway.
paul@44 1097
paul@44 1098
            if have_usage and have_no_usage_branch:
paul@44 1099
                self.init_definition_details(location)
paul@44 1100
                self.record_types_for_usage(location, None)
paul@44 1101
paul@44 1102
        # Specific name-based attribute accesses.
paul@44 1103
paul@44 1104
        alias_accesses = set()
paul@44 1105
paul@44 1106
        for access_location, accessor_locations in self.access_index.items():
paul@44 1107
            self.record_types_for_access(access_location, accessor_locations, alias_accesses)
paul@44 1108
paul@44 1109
        # Anonymous references with attribute chains.
paul@44 1110
paul@44 1111
        for location, accesses in self.importer.all_attr_accesses.items():
paul@44 1112
paul@44 1113
            # Get distinct attribute names.
paul@44 1114
paul@44 1115
            all_attrnames = set()
paul@44 1116
paul@44 1117
            for attrnames in accesses:
paul@44 1118
                all_attrnames.update(get_attrnames(attrnames))
paul@44 1119
paul@44 1120
            # Get attribute and accessor details for each attribute name.
paul@44 1121
paul@44 1122
            for attrname in all_attrnames:
paul@44 1123
                access_location = (location, None, attrname, 0)
paul@44 1124
                self.record_types_for_attribute(access_location, attrname)
paul@44 1125
paul@44 1126
        # References via constant/identified objects.
paul@44 1127
paul@44 1128
        for location, name_accesses in self.importer.all_const_accesses.items():
paul@44 1129
paul@44 1130
            # A mapping from the original name and attributes to resolved access
paul@44 1131
            # details.
paul@44 1132
paul@44 1133
            for original_access, access in name_accesses.items():
paul@44 1134
                original_name, original_attrnames = original_access
paul@44 1135
                objpath, ref, attrnames = access
paul@44 1136
paul@44 1137
                # Build an accessor combining the name and attribute names used.
paul@44 1138
paul@44 1139
                original_accessor = tuple([original_name] + original_attrnames.split("."))
paul@44 1140
paul@44 1141
                # Direct accesses to attributes.
paul@44 1142
paul@44 1143
                if not attrnames:
paul@44 1144
paul@44 1145
                    # Build a descriptive location based on the original
paul@44 1146
                    # details, exposing the final attribute name.
paul@44 1147
paul@44 1148
                    oa, attrname = original_accessor[:-1], original_accessor[-1]
paul@44 1149
                    oa = ".".join(oa)
paul@44 1150
paul@44 1151
                    access_location = (location, oa, attrname, 0)
paul@44 1152
                    accessor_location = (location, oa, None, 0)
paul@44 1153
                    self.access_index[access_location] = [accessor_location]
paul@44 1154
paul@44 1155
                    self.init_access_details(access_location)
paul@44 1156
                    self.init_definition_details(accessor_location)
paul@44 1157
paul@44 1158
                    # Obtain a reference for the accessor in order to properly
paul@44 1159
                    # determine its type.
paul@44 1160
paul@44 1161
                    if ref.get_kind() != "<instance>":
paul@44 1162
                        objpath = ref.get_origin()
paul@44 1163
paul@44 1164
                    objpath = objpath.rsplit(".", 1)[0]
paul@44 1165
paul@44 1166
                    # Where the object name conflicts with the module
paul@44 1167
                    # providing it, obtain the module details.
paul@44 1168
paul@44 1169
                    if objpath in self.importer.modules:
paul@44 1170
                        accessor = Reference("<module>", objpath)
paul@44 1171
                    else:
paul@44 1172
                        accessor = self.importer.get_object(objpath)
paul@44 1173
paul@44 1174
                    self.referenced_attrs[access_location] = [(accessor.get_kind(), accessor.get_origin(), ref)]
paul@44 1175
                    self.access_constrained.add(access_location)
paul@44 1176
paul@57 1177
                    class_types, instance_types, module_types = accessor.get_types()
paul@44 1178
                    self.record_reference_types(accessor_location, class_types, instance_types, module_types, True, True)
paul@64 1179
paul@64 1180
                else:
paul@44 1181
paul@64 1182
                    # Build a descriptive location based on the original
paul@64 1183
                    # details, employing the first remaining attribute name.
paul@64 1184
paul@64 1185
                    l = get_attrnames(attrnames)
paul@64 1186
                    attrname = l[0]
paul@44 1187
paul@64 1188
                    oa = original_accessor[:-len(l)]
paul@64 1189
                    oa = ".".join(oa)
paul@44 1190
paul@64 1191
                    access_location = (location, oa, attrnames, 0)
paul@64 1192
                    accessor_location = (location, oa, None, 0)
paul@64 1193
                    self.access_index[access_location] = [accessor_location]
paul@64 1194
paul@64 1195
                    self.init_access_details(access_location)
paul@64 1196
                    self.init_definition_details(accessor_location)
paul@44 1197
paul@64 1198
                    class_types, instance_types, module_types = ref.get_types()
paul@64 1199
paul@64 1200
                    self.identify_reference_attributes(access_location, attrname, class_types, instance_types, module_types, True)
paul@64 1201
                    self.record_reference_types(accessor_location, class_types, instance_types, module_types, True, True)
paul@64 1202
paul@64 1203
                original_location = (location, original_name, original_attrnames, 0)
paul@64 1204
paul@64 1205
                if original_location != access_location:
paul@64 1206
                    self.const_accesses[original_location] = access_location
paul@67 1207
                    self.const_accesses_rev[access_location] = original_location
paul@44 1208
paul@64 1209
        # Aliased name definitions. All aliases with usage will have been
paul@64 1210
        # defined, but they may be refined according to referenced accesses.
paul@44 1211
paul@64 1212
        for accessor_location in self.alias_index.keys():
paul@64 1213
            self.record_types_for_alias(accessor_location)
paul@44 1214
paul@64 1215
        # Update accesses employing aliases.
paul@64 1216
paul@64 1217
        for access_location in alias_accesses:
paul@64 1218
            self.record_types_for_access(access_location, self.access_index[access_location])
paul@44 1219
paul@44 1220
    def constrain_types(self, path, class_types, instance_types, module_types):
paul@44 1221
paul@44 1222
        """
paul@44 1223
        Using the given 'path' to an object, constrain the given 'class_types',
paul@44 1224
        'instance_types' and 'module_types'.
paul@44 1225
paul@44 1226
        Return the class, instance, module types plus whether the types are
paul@44 1227
        constrained to a specific kind of type.
paul@44 1228
        """
paul@44 1229
paul@44 1230
        ref = self.importer.identify(path)
paul@44 1231
        if ref:
paul@44 1232
paul@44 1233
            # Constrain usage suggestions using the identified object.
paul@44 1234
paul@44 1235
            if ref.has_kind("<class>"):
paul@44 1236
                return (
paul@44 1237
                    set(class_types).intersection([ref.get_origin()]), [], [], True
paul@44 1238
                    )
paul@44 1239
            elif ref.has_kind("<module>"):
paul@44 1240
                return (
paul@44 1241
                    [], [], set(module_types).intersection([ref.get_origin()]), True
paul@44 1242
                    )
paul@44 1243
paul@44 1244
        return class_types, instance_types, module_types, False
paul@44 1245
paul@44 1246
    def get_target_types(self, location, usage):
paul@44 1247
paul@44 1248
        """
paul@44 1249
        Return the class, instance and module types constrained for the name at
paul@44 1250
        the given 'location' exhibiting the given 'usage'. Whether the types
paul@44 1251
        have been constrained using contextual information is also indicated,
paul@44 1252
        plus whether the types have been constrained to a specific kind of type.
paul@44 1253
        """
paul@44 1254
paul@44 1255
        unit_path, name, attrnames, version = location
paul@107 1256
        have_assignments = get_assigned_attributes(usage)
paul@44 1257
paul@44 1258
        # Detect any initialised name for the location.
paul@44 1259
paul@44 1260
        if name:
paul@44 1261
            ref = self.get_initialised_name(location)
paul@44 1262
            if ref:
paul@44 1263
                (class_types, only_instance_types, module_types,
paul@57 1264
                    _function_types, _var_types) = separate_types([ref])
paul@107 1265
                return class_types, only_instance_types, module_types, True, have_assignments
paul@44 1266
paul@44 1267
        # Retrieve the recorded types for the usage.
paul@44 1268
paul@44 1269
        class_types = self.get_class_types_for_usage(usage)
paul@44 1270
        only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types)
paul@44 1271
        module_types = self.get_module_types_for_usage(usage)
paul@44 1272
paul@44 1273
        # Merge usage deductions with observations to obtain reference types
paul@44 1274
        # for names involved with attribute accesses.
paul@44 1275
paul@44 1276
        if not name:
paul@107 1277
            return class_types, only_instance_types, module_types, False, have_assignments
paul@44 1278
paul@44 1279
        # Obtain references to known objects.
paul@44 1280
paul@85 1281
        path = get_name_path(unit_path, name)
paul@44 1282
paul@44 1283
        class_types, only_instance_types, module_types, constrained_specific = \
paul@44 1284
            self.constrain_types(path, class_types, only_instance_types, module_types)
paul@44 1285
paul@44 1286
        if constrained_specific:
paul@107 1287
            return class_types, only_instance_types, module_types, constrained_specific, \
paul@107 1288
                constrained_specific or have_assignments
paul@44 1289
paul@44 1290
        # Constrain "self" references.
paul@44 1291
paul@44 1292
        if name == "self":
paul@44 1293
            t = self.constrain_self_reference(unit_path, class_types, only_instance_types)
paul@44 1294
            if t:
paul@44 1295
                class_types, only_instance_types, module_types, constrained = t
paul@107 1296
                return class_types, only_instance_types, module_types, constrained, have_assignments
paul@107 1297
paul@107 1298
        return class_types, only_instance_types, module_types, False, have_assignments
paul@44 1299
paul@44 1300
    def constrain_self_reference(self, unit_path, class_types, only_instance_types):
paul@44 1301
paul@44 1302
        """
paul@44 1303
        Where the name "self" appears in a method, attempt to constrain the
paul@44 1304
        classes involved.
paul@44 1305
paul@44 1306
        Return the class, instance, module types plus whether the types are
paul@44 1307
        constrained.
paul@44 1308
        """
paul@44 1309
paul@44 1310
        class_name = self.in_method(unit_path)
paul@44 1311
paul@44 1312
        if not class_name:
paul@44 1313
            return None
paul@44 1314
paul@44 1315
        classes = set([class_name])
paul@44 1316
        classes.update(self.get_descendants_for_class(class_name))
paul@44 1317
paul@44 1318
        # Note that only instances will be expected for these references but
paul@44 1319
        # either classes or instances may provide the attributes.
paul@44 1320
paul@44 1321
        return (
paul@44 1322
            set(class_types).intersection(classes),
paul@44 1323
            set(only_instance_types).intersection(classes),
paul@44 1324
            [], True
paul@44 1325
            )
paul@44 1326
paul@44 1327
    def in_method(self, path):
paul@44 1328
paul@44 1329
        "Return whether 'path' refers to a method."
paul@44 1330
paul@44 1331
        class_name, method_name = path.rsplit(".", 1)
paul@44 1332
        return self.importer.classes.has_key(class_name) and class_name
paul@44 1333
paul@44 1334
    def init_reference_details(self, location):
paul@44 1335
paul@44 1336
        "Initialise reference-related details for 'location'."
paul@44 1337
paul@44 1338
        self.init_definition_details(location)
paul@44 1339
        self.init_access_details(location)
paul@44 1340
paul@44 1341
    def init_definition_details(self, location):
paul@44 1342
paul@44 1343
        "Initialise name definition details for 'location'."
paul@44 1344
paul@44 1345
        self.accessor_class_types[location] = set()
paul@44 1346
        self.accessor_instance_types[location] = set()
paul@44 1347
        self.accessor_module_types[location] = set()
paul@44 1348
        self.provider_class_types[location] = set()
paul@44 1349
        self.provider_instance_types[location] = set()
paul@44 1350
        self.provider_module_types[location] = set()
paul@44 1351
paul@44 1352
    def init_access_details(self, location):
paul@44 1353
paul@44 1354
        "Initialise access details at 'location'."
paul@44 1355
paul@44 1356
        self.referenced_attrs[location] = {}
paul@44 1357
paul@44 1358
    def record_types_for_access(self, access_location, accessor_locations, alias_accesses=None):
paul@44 1359
paul@44 1360
        """
paul@44 1361
        Define types for the 'access_location' associated with the given
paul@44 1362
        'accessor_locations'.
paul@44 1363
        """
paul@44 1364
paul@91 1365
        attrname = get_attrname_from_location(access_location)
paul@91 1366
        if not attrname:
paul@44 1367
            return
paul@44 1368
paul@44 1369
        # Collect all suggested types for the accessors. Accesses may
paul@44 1370
        # require accessors from of a subset of the complete set of types.
paul@44 1371
paul@44 1372
        class_types = set()
paul@44 1373
        module_types = set()
paul@44 1374
        instance_types = set()
paul@44 1375
paul@44 1376
        constrained = True
paul@44 1377
paul@44 1378
        for location in accessor_locations:
paul@44 1379
paul@44 1380
            # Remember accesses employing aliases.
paul@44 1381
paul@44 1382
            if alias_accesses is not None and self.alias_index.has_key(location):
paul@44 1383
                alias_accesses.add(access_location)
paul@44 1384
paul@44 1385
            # Use the type information deduced for names from above.
paul@44 1386
paul@44 1387
            if self.accessor_class_types.has_key(location):
paul@44 1388
                class_types.update(self.accessor_class_types[location])
paul@44 1389
                module_types.update(self.accessor_module_types[location])
paul@44 1390
                instance_types.update(self.accessor_instance_types[location])
paul@44 1391
paul@44 1392
            # Where accesses are associated with assignments but where no
paul@44 1393
            # attribute usage observations have caused such an association,
paul@44 1394
            # the attribute name is considered by itself.
paul@44 1395
paul@44 1396
            else:
paul@44 1397
                self.init_definition_details(location)
paul@107 1398
                self.record_types_for_usage(location, [(attrname, False, False)])
paul@44 1399
paul@67 1400
            constrained = location in self.accessor_constrained and constrained
paul@44 1401
paul@44 1402
        self.init_access_details(access_location)
paul@44 1403
        self.identify_reference_attributes(access_location, attrname, class_types, instance_types, module_types, constrained)
paul@44 1404
paul@44 1405
    def record_types_for_usage(self, accessor_location, usage):
paul@44 1406
paul@44 1407
        """
paul@44 1408
        Record types for the given 'accessor_location' according to the given
paul@44 1409
        'usage' observations which may be None to indicate an absence of usage.
paul@44 1410
        """
paul@44 1411
paul@44 1412
        (class_types,
paul@44 1413
         instance_types,
paul@44 1414
         module_types,
paul@44 1415
         constrained,
paul@44 1416
         constrained_specific) = self.get_target_types(accessor_location, usage)
paul@44 1417
paul@90 1418
        invocations = get_invoked_attributes(usage)
paul@90 1419
paul@107 1420
        self.record_reference_types(accessor_location, class_types, instance_types,
paul@107 1421
            module_types, constrained, constrained_specific, invocations)
paul@44 1422
paul@44 1423
    def record_types_for_attribute(self, access_location, attrname):
paul@44 1424
paul@44 1425
        """
paul@44 1426
        Record types for the 'access_location' employing only the given
paul@44 1427
        'attrname' for type deduction.
paul@44 1428
        """
paul@44 1429
paul@102 1430
        (class_types,
paul@102 1431
         only_instance_types,
paul@102 1432
         module_types) = self.get_types_for_attribute(attrname)
paul@102 1433
paul@102 1434
        self.init_reference_details(access_location)
paul@102 1435
paul@102 1436
        self.identify_reference_attributes(access_location, attrname, class_types, only_instance_types, module_types, False)
paul@102 1437
        self.record_reference_types(access_location, class_types, only_instance_types, module_types, False)
paul@102 1438
paul@102 1439
    def get_types_for_attribute(self, attrname):
paul@102 1440
paul@102 1441
        "Return class, instance-only and module types supporting 'attrname'."
paul@102 1442
paul@107 1443
        usage = ((attrname, False, False),)
paul@44 1444
paul@44 1445
        class_types = self.get_class_types_for_usage(usage)
paul@44 1446
        only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types)
paul@44 1447
        module_types = self.get_module_types_for_usage(usage)
paul@44 1448
paul@102 1449
        return class_types, only_instance_types, module_types
paul@44 1450
paul@44 1451
    def record_types_for_alias(self, accessor_location):
paul@44 1452
paul@44 1453
        """
paul@44 1454
        Define types for the 'accessor_location' not having associated usage.
paul@44 1455
        """
paul@44 1456
paul@44 1457
        have_access = self.provider_class_types.has_key(accessor_location)
paul@44 1458
paul@44 1459
        # With an access, attempt to narrow the existing selection of provider
paul@44 1460
        # types.
paul@44 1461
paul@44 1462
        if have_access:
paul@44 1463
            provider_class_types = self.provider_class_types[accessor_location]
paul@44 1464
            provider_instance_types = self.provider_instance_types[accessor_location]
paul@44 1465
            provider_module_types = self.provider_module_types[accessor_location]
paul@44 1466
paul@44 1467
            # Find details for any corresponding access.
paul@44 1468
paul@44 1469
            all_class_types = set()
paul@44 1470
            all_instance_types = set()
paul@44 1471
            all_module_types = set()
paul@44 1472
paul@44 1473
            for access_location in self.alias_index[accessor_location]:
paul@44 1474
                location, name, attrnames, access_number = access_location
paul@44 1475
paul@44 1476
                # Alias references an attribute access.
paul@44 1477
paul@44 1478
                if attrnames:
paul@44 1479
paul@44 1480
                    # Obtain attribute references for the access.
paul@44 1481
paul@44 1482
                    attrs = [attr for _attrtype, object_type, attr in self.referenced_attrs[access_location]]
paul@44 1483
paul@44 1484
                    # Separate the different attribute types.
paul@44 1485
paul@44 1486
                    (class_types, instance_types, module_types,
paul@57 1487
                        function_types, var_types) = separate_types(attrs)
paul@44 1488
paul@44 1489
                    # Where non-accessor types are found, do not attempt to refine
paul@44 1490
                    # the defined accessor types.
paul@44 1491
paul@44 1492
                    if function_types or var_types:
paul@44 1493
                        return
paul@44 1494
paul@44 1495
                    class_types = set(provider_class_types).intersection(class_types)
paul@44 1496
                    instance_types = set(provider_instance_types).intersection(instance_types)
paul@44 1497
                    module_types = set(provider_module_types).intersection(module_types)
paul@44 1498
paul@44 1499
                # Alias references a name, not an access.
paul@44 1500
paul@44 1501
                else:
paul@44 1502
                    # Attempt to refine the types using initialised names.
paul@44 1503
paul@44 1504
                    attr = self.get_initialised_name(access_location)
paul@44 1505
                    if attr:
paul@44 1506
                        (class_types, instance_types, module_types,
paul@57 1507
                            _function_types, _var_types) = separate_types([attr])
paul@44 1508
paul@44 1509
                    # Where no further information is found, do not attempt to
paul@44 1510
                    # refine the defined accessor types.
paul@44 1511
paul@44 1512
                    else:
paul@44 1513
                        return
paul@44 1514
paul@44 1515
                all_class_types.update(class_types)
paul@44 1516
                all_instance_types.update(instance_types)
paul@44 1517
                all_module_types.update(module_types)
paul@44 1518
paul@44 1519
            # Record refined type details for the alias as an accessor.
paul@44 1520
paul@44 1521
            self.init_definition_details(accessor_location)
paul@44 1522
            self.record_reference_types(accessor_location, all_class_types, all_instance_types, all_module_types, False)
paul@44 1523
paul@44 1524
        # Without an access, attempt to identify references for the alias.
paul@44 1525
paul@44 1526
        else:
paul@44 1527
            refs = set()
paul@44 1528
paul@44 1529
            for access_location in self.alias_index[accessor_location]:
paul@64 1530
paul@64 1531
                # Obtain any redefined constant access location.
paul@64 1532
paul@64 1533
                if self.const_accesses.has_key(access_location):
paul@64 1534
                    access_location = self.const_accesses[access_location]
paul@64 1535
paul@44 1536
                location, name, attrnames, access_number = access_location
paul@44 1537
paul@44 1538
                # Alias references an attribute access.
paul@44 1539
paul@44 1540
                if attrnames:
paul@44 1541
                    attrs = [attr for attrtype, object_type, attr in self.referenced_attrs[access_location]]
paul@44 1542
                    refs.update(attrs)
paul@44 1543
paul@44 1544
                # Alias references a name, not an access.
paul@44 1545
paul@44 1546
                else:
paul@44 1547
                    attr = self.get_initialised_name(access_location)
paul@44 1548
                    attrs = attr and [attr] or []
paul@44 1549
                    if not attrs and self.provider_class_types.has_key(access_location):
paul@44 1550
                        class_types = self.provider_class_types[access_location]
paul@44 1551
                        instance_types = self.provider_instance_types[access_location]
paul@44 1552
                        module_types = self.provider_module_types[access_location]
paul@57 1553
                        attrs = combine_types(class_types, instance_types, module_types)
paul@44 1554
                    if attrs:
paul@44 1555
                        refs.update(attrs)
paul@44 1556
paul@44 1557
            # Record reference details for the alias separately from accessors.
paul@44 1558
paul@44 1559
            self.referenced_objects[accessor_location] = refs
paul@44 1560
paul@44 1561
    def get_initialised_name(self, access_location):
paul@44 1562
paul@44 1563
        """
paul@44 1564
        Return references for any initialised names at 'access_location', or
paul@44 1565
        None if no such references exist.
paul@44 1566
        """
paul@44 1567
paul@44 1568
        location, name, attrnames, version = access_location
paul@85 1569
        path = get_name_path(location, name)
paul@44 1570
paul@44 1571
        # Use initialiser information, if available.
paul@44 1572
paul@44 1573
        refs = self.importer.all_initialised_names.get(path)
paul@44 1574
        if refs and refs.has_key(version):
paul@44 1575
            return refs[version]
paul@44 1576
        else:
paul@44 1577
            return None
paul@44 1578
paul@44 1579
    def record_reference_types(self, location, class_types, instance_types,
paul@90 1580
        module_types, constrained, constrained_specific=False, invocations=None):
paul@44 1581
paul@44 1582
        """
paul@44 1583
        Associate attribute provider types with the given 'location', consisting
paul@44 1584
        of the given 'class_types', 'instance_types' and 'module_types'.
paul@44 1585
paul@44 1586
        If 'constrained' is indicated, the constrained nature of the accessor is
paul@44 1587
        recorded for the location.
paul@44 1588
paul@44 1589
        If 'constrained_specific' is indicated using a true value, instance types
paul@44 1590
        will not be added to class types to permit access via instances at the
paul@44 1591
        given location. This is only useful where a specific accessor is known
paul@44 1592
        to be a class.
paul@44 1593
paul@105 1594
        If 'invocations' is given, the given attribute names indicate those
paul@105 1595
        which are involved in invocations. Such invocations, if involving
paul@105 1596
        functions, will employ those functions as bound methods and will
paul@105 1597
        therefore not support classes as accessors, only instances of such
paul@105 1598
        classes.
paul@105 1599
paul@44 1600
        Note that the specified types only indicate the provider types for
paul@44 1601
        attributes, whereas the recorded accessor types indicate the possible
paul@44 1602
        types of the actual objects used to access attributes.
paul@44 1603
        """
paul@44 1604
paul@44 1605
        # Update the type details for the location.
paul@44 1606
paul@44 1607
        self.provider_class_types[location].update(class_types)
paul@44 1608
        self.provider_instance_types[location].update(instance_types)
paul@44 1609
        self.provider_module_types[location].update(module_types)
paul@44 1610
paul@44 1611
        # Class types support classes and instances as accessors.
paul@44 1612
        # Instance-only and module types support only their own kinds as
paul@44 1613
        # accessors.
paul@44 1614
paul@90 1615
        path, name, version, attrnames = location
paul@90 1616
paul@90 1617
        if invocations:
paul@90 1618
            class_only_types = self.filter_for_invocations(class_types, invocations)
paul@90 1619
        else:
paul@90 1620
            class_only_types = class_types
paul@90 1621
paul@44 1622
        # However, the nature of accessors can be further determined.
paul@44 1623
        # Any self variable may only refer to an instance.
paul@44 1624
paul@44 1625
        if name != "self" or not self.in_method(path):
paul@90 1626
            self.accessor_class_types[location].update(class_only_types)
paul@44 1627
paul@44 1628
        if not constrained_specific:
paul@44 1629
            self.accessor_instance_types[location].update(class_types)
paul@44 1630
paul@44 1631
        self.accessor_instance_types[location].update(instance_types)
paul@44 1632
paul@44 1633
        if name != "self" or not self.in_method(path):
paul@44 1634
            self.accessor_module_types[location].update(module_types)
paul@44 1635
paul@44 1636
        if constrained:
paul@67 1637
            self.accessor_constrained.add(location)
paul@44 1638
paul@90 1639
    def filter_for_invocations(self, class_types, attrnames):
paul@90 1640
paul@90 1641
        """
paul@90 1642
        From the given 'class_types', identify methods for the given
paul@90 1643
        'attrnames' that are being invoked, returning a filtered collection of
paul@90 1644
        class types.
paul@90 1645
        """
paul@90 1646
paul@90 1647
        to_filter = set()
paul@90 1648
paul@90 1649
        for class_type in class_types:
paul@90 1650
            for attrname in attrnames:
paul@90 1651
                ref = self.importer.get_class_attribute(class_type, attrname)
paul@90 1652
                parent_class = ref and ref.parent()
paul@90 1653
paul@90 1654
                if ref and ref.has_kind("<function>") and (
paul@90 1655
                   parent_class == class_type or
paul@90 1656
                   class_type in self.descendants[parent_class]):
paul@90 1657
paul@90 1658
                    to_filter.add(class_type)
paul@90 1659
                    break
paul@90 1660
paul@90 1661
        return set(class_types).difference(to_filter)
paul@90 1662
paul@44 1663
    def identify_reference_attributes(self, location, attrname, class_types, instance_types, module_types, constrained):
paul@44 1664
paul@44 1665
        """
paul@44 1666
        Identify reference attributes, associating them with the given
paul@44 1667
        'location', identifying the given 'attrname', employing the given
paul@44 1668
        'class_types', 'instance_types' and 'module_types'.
paul@44 1669
paul@44 1670
        If 'constrained' is indicated, the constrained nature of the access is
paul@44 1671
        recorded for the location.
paul@44 1672
        """
paul@44 1673
paul@44 1674
        # Record the referenced objects.
paul@44 1675
paul@44 1676
        self.referenced_attrs[location] = \
paul@44 1677
            self._identify_reference_attribute(attrname, class_types, instance_types, module_types)
paul@44 1678
paul@44 1679
        if constrained:
paul@44 1680
            self.access_constrained.add(location)
paul@44 1681
paul@44 1682
    def _identify_reference_attribute(self, attrname, class_types, instance_types, module_types):
paul@44 1683
paul@44 1684
        """
paul@44 1685
        Identify the reference attribute with the given 'attrname', employing
paul@44 1686
        the given 'class_types', 'instance_types' and 'module_types'.
paul@44 1687
        """
paul@44 1688
paul@44 1689
        attrs = set()
paul@44 1690
paul@44 1691
        # The class types expose class attributes either directly or via
paul@44 1692
        # instances.
paul@44 1693
paul@44 1694
        for object_type in class_types:
paul@44 1695
            ref = self.importer.get_class_attribute(object_type, attrname)
paul@44 1696
            if ref:
paul@44 1697
                attrs.add(("<class>", object_type, ref))
paul@44 1698
paul@44 1699
            # Add any distinct instance attributes that would be provided
paul@44 1700
            # by instances also providing indirect class attribute access.
paul@44 1701
paul@44 1702
            for ref in self.importer.get_instance_attributes(object_type, attrname):
paul@44 1703
                attrs.add(("<instance>", object_type, ref))
paul@44 1704
paul@44 1705
        # The instance-only types expose instance attributes, but although
paul@44 1706
        # classes are excluded as potential accessors (since they do not provide
paul@44 1707
        # the instance attributes), the class types may still provide some
paul@44 1708
        # attributes.
paul@44 1709
paul@44 1710
        for object_type in instance_types:
paul@44 1711
            instance_attrs = self.importer.get_instance_attributes(object_type, attrname)
paul@44 1712
paul@44 1713
            if instance_attrs:
paul@44 1714
                for ref in instance_attrs:
paul@44 1715
                    attrs.add(("<instance>", object_type, ref))
paul@44 1716
            else:
paul@44 1717
                ref = self.importer.get_class_attribute(object_type, attrname)
paul@44 1718
                if ref:
paul@44 1719
                    attrs.add(("<class>", object_type, ref))
paul@44 1720
paul@44 1721
        # Module types expose module attributes for module accessors.
paul@44 1722
paul@44 1723
        for object_type in module_types:
paul@44 1724
            ref = self.importer.get_module_attribute(object_type, attrname)
paul@44 1725
            if ref:
paul@44 1726
                attrs.add(("<module>", object_type, ref))
paul@44 1727
paul@44 1728
        return attrs
paul@44 1729
paul@70 1730
    constrained_specific_tests = (
paul@70 1731
        "constrained-specific-instance",
paul@70 1732
        "constrained-specific-type",
paul@70 1733
        "constrained-specific-object",
paul@70 1734
        )
paul@70 1735
paul@70 1736
    constrained_common_tests = (
paul@70 1737
        "constrained-common-instance",
paul@70 1738
        "constrained-common-type",
paul@70 1739
        "constrained-common-object",
paul@70 1740
        )
paul@70 1741
paul@67 1742
    guarded_specific_tests = (
paul@67 1743
        "guarded-specific-instance",
paul@67 1744
        "guarded-specific-type",
paul@67 1745
        "guarded-specific-object",
paul@67 1746
        )
paul@67 1747
paul@67 1748
    guarded_common_tests = (
paul@67 1749
        "guarded-common-instance",
paul@67 1750
        "guarded-common-type",
paul@67 1751
        "guarded-common-object",
paul@67 1752
        )
paul@67 1753
paul@67 1754
    specific_tests = (
paul@67 1755
        "specific-instance",
paul@67 1756
        "specific-type",
paul@67 1757
        "specific-object",
paul@67 1758
        )
paul@67 1759
paul@67 1760
    common_tests = (
paul@67 1761
        "common-instance",
paul@67 1762
        "common-type",
paul@67 1763
        "common-object",
paul@67 1764
        )
paul@67 1765
paul@67 1766
    class_tests = (
paul@67 1767
        "guarded-specific-type",
paul@67 1768
        "guarded-common-type",
paul@67 1769
        "specific-type",
paul@67 1770
        "common-type",
paul@67 1771
        )
paul@67 1772
paul@67 1773
    class_or_instance_tests = (
paul@67 1774
        "guarded-specific-object",
paul@67 1775
        "guarded-common-object",
paul@67 1776
        "specific-object",
paul@67 1777
        "common-object",
paul@67 1778
        )
paul@67 1779
paul@67 1780
    def get_access_plan(self, location):
paul@65 1781
paul@77 1782
        """
paul@77 1783
        Return details of the access at the given 'location'. The details are as
paul@77 1784
        follows:
paul@77 1785
paul@77 1786
         * the initial accessor (from which accesses will be performed if no
paul@77 1787
           computed static accessor is found)
paul@77 1788
         * details of any test required on the initial accessor
paul@77 1789
         * details of any type employed by the test
paul@77 1790
         * any static accessor (from which accesses will be performed in
paul@77 1791
           preference to the initial accessor)
paul@77 1792
         * attributes needing to be traversed from the base that yield
paul@77 1793
           unambiguous objects
paul@98 1794
         * access modes for each of the unambiguously-traversed attributes
paul@77 1795
         * remaining attributes needing to be tested and traversed
paul@77 1796
         * details of the context
paul@102 1797
         * any test to apply to the context
paul@77 1798
         * the method of obtaining the final attribute
paul@77 1799
         * any static final attribute
paul@77 1800
        """
paul@65 1801
paul@67 1802
        const_access = self.const_accesses_rev.has_key(location)
paul@65 1803
paul@75 1804
        path, name, attrnames, version = location
paul@75 1805
        remaining = attrnames.split(".")
paul@75 1806
        attrname = remaining[0]
paul@65 1807
paul@67 1808
        # Obtain reference and accessor information, retaining also distinct
paul@67 1809
        # provider kind details.
paul@65 1810
paul@65 1811
        attrs = []
paul@65 1812
        objtypes = []
paul@67 1813
        provider_kinds = set()
paul@67 1814
paul@65 1815
        for attrtype, objtype, attr in self.referenced_attrs[location]:
paul@65 1816
            attrs.append(attr)
paul@65 1817
            objtypes.append(objtype)
paul@67 1818
            provider_kinds.add(attrtype)
paul@67 1819
paul@67 1820
        # Obtain accessor type and kind information.
paul@67 1821
paul@67 1822
        accessor_types = self.reference_all_accessor_types[location]
paul@67 1823
        accessor_general_types = self.reference_all_accessor_general_types[location]
paul@67 1824
        accessor_kinds = get_kinds(accessor_general_types)
paul@67 1825
paul@67 1826
        # Determine any guard or test requirements.
paul@67 1827
paul@67 1828
        constrained = location in self.access_constrained
paul@70 1829
        test = self.reference_test_types[location]
paul@77 1830
        test_type = self.reference_test_accessor_type.get(location)
paul@67 1831
paul@67 1832
        # Determine the accessor and provider properties.
paul@67 1833
paul@67 1834
        class_accessor = "<class>" in accessor_kinds
paul@67 1835
        module_accessor = "<module>" in accessor_kinds
paul@67 1836
        instance_accessor = "<instance>" in accessor_kinds
paul@67 1837
        provided_by_class = "<class>" in provider_kinds
paul@67 1838
        provided_by_instance = "<instance>" in provider_kinds
paul@67 1839
paul@74 1840
        # Determine how attributes may be accessed relative to the accessor.
paul@74 1841
paul@74 1842
        object_relative = class_accessor or module_accessor or provided_by_instance
paul@74 1843
        class_relative = instance_accessor and provided_by_class
paul@74 1844
paul@67 1845
        # Identify the last static attribute for context acquisition.
paul@67 1846
paul@67 1847
        base = None
paul@67 1848
        dynamic_base = None
paul@67 1849
paul@67 1850
        # Constant accesses have static accessors.
paul@65 1851
paul@65 1852
        if const_access:
paul@65 1853
            base = len(objtypes) == 1 and first(objtypes)
paul@67 1854
paul@67 1855
        # Constant accessors are static.
paul@67 1856
paul@65 1857
        else:
paul@65 1858
            ref = self.importer.identify("%s.%s" % (path, name))
paul@67 1859
            if ref:
paul@65 1860
                base = ref.get_origin()
paul@65 1861
paul@70 1862
            # Usage of previously-generated guard and test details.
paul@70 1863
paul@70 1864
            elif test in self.constrained_specific_tests:
paul@67 1865
                ref = first(accessor_types)
paul@67 1866
paul@70 1867
            elif test in self.constrained_common_tests:
paul@67 1868
                ref = first(accessor_general_types)
paul@67 1869
paul@67 1870
            elif test in self.guarded_specific_tests:
paul@67 1871
                ref = first(accessor_types)
paul@67 1872
paul@67 1873
            elif test in self.guarded_common_tests:
paul@67 1874
                ref = first(accessor_general_types)
paul@67 1875
paul@70 1876
            # For attribute-based tests, tentatively identify a dynamic base.
paul@70 1877
            # Such tests allow single or multiple kinds of a type.
paul@70 1878
paul@67 1879
            elif test in self.common_tests or test in self.specific_tests:
paul@77 1880
                dynamic_base = test_type
paul@67 1881
paul@67 1882
            # Static accessors.
paul@67 1883
paul@70 1884
            if not base and test in self.class_tests:
paul@70 1885
                base = ref and ref.get_origin() or dynamic_base
paul@70 1886
paul@70 1887
            # Accessors that are not static but whose nature is determined.
paul@70 1888
paul@70 1889
            elif not base and ref:
paul@67 1890
                dynamic_base = ref.get_origin()
paul@67 1891
paul@102 1892
        # Determine initial accessor details.
paul@102 1893
paul@102 1894
        accessor = base or dynamic_base
paul@102 1895
        accessor_kind = len(accessor_kinds) == 1 and first(accessor_kinds) or None
paul@102 1896
        provider_kind = len(provider_kinds) == 1 and first(provider_kinds) or None
paul@102 1897
paul@102 1898
        # Traverse remaining attributes.
paul@102 1899
paul@65 1900
        traversed = []
paul@96 1901
        traversal_modes = []
paul@65 1902
paul@65 1903
        while len(attrs) == 1:
paul@65 1904
            attr = first(attrs)
paul@65 1905
paul@65 1906
            traversed.append(attrname)
paul@96 1907
            traversal_modes.append(accessor_kind == provider_kind and "object" or "class")
paul@96 1908
paul@102 1909
            # Consume attribute names providing unambiguous attributes.
paul@102 1910
paul@75 1911
            del remaining[0]
paul@75 1912
paul@75 1913
            if not remaining:
paul@65 1914
                break
paul@65 1915
paul@67 1916
            # Update the last static attribute.
paul@67 1917
paul@65 1918
            if attr.static():
paul@65 1919
                base = attr.get_origin()
paul@65 1920
                traversed = []
paul@96 1921
                traversal_modes = []
paul@65 1922
paul@102 1923
            # Get the access details.
paul@67 1924
paul@75 1925
            attrname = remaining[0]
paul@102 1926
            accessor = attr.get_origin()
paul@102 1927
            accessor_kind = attr.get_kind()
paul@102 1928
            provider_kind = self.importer.get_attribute_provider(attr, attrname)
paul@102 1929
            accessor_kinds = [accessor_kind]
paul@102 1930
            provider_kinds = [provider_kind]
paul@102 1931
paul@102 1932
            # Get the next attribute.
paul@102 1933
paul@65 1934
            attrs = self.importer.get_attributes(attr, attrname)
paul@67 1935
paul@67 1936
        # Where many attributes are suggested, no single attribute identity can
paul@67 1937
        # be loaded.
paul@67 1938
paul@65 1939
        else:
paul@65 1940
            attr = None
paul@65 1941
paul@67 1942
        # Determine the method of access.
paul@67 1943
paul@98 1944
        is_assignment = location in self.reference_assignments
paul@98 1945
paul@71 1946
        # Identified attribute that must be accessed via its parent.
paul@71 1947
paul@98 1948
        if attr and attr.get_name() and is_assignment:
paul@98 1949
            final_method = "static-assign"; origin = attr.get_name()
paul@71 1950
paul@67 1951
        # Static, identified attribute.
paul@67 1952
paul@71 1953
        elif attr and attr.static():
paul@98 1954
            final_method = is_assignment and "static-assign" or "static"
paul@98 1955
            origin = attr.final()
paul@94 1956
paul@94 1957
        # All other methods of access involve traversal.
paul@94 1958
paul@94 1959
        else:
paul@98 1960
            final_method = is_assignment and "assign" or "access"
paul@98 1961
            origin = None
paul@67 1962
paul@93 1963
        # First attribute accessed at a known position via the accessor.
paul@67 1964
paul@94 1965
        if base or dynamic_base:
paul@94 1966
            first_method = "relative" + (object_relative and "-object" or "") + \
paul@94 1967
                                        (class_relative and "-class" or "")
paul@67 1968
paul@67 1969
        # The fallback case is always run-time testing and access.
paul@67 1970
paul@67 1971
        else:
paul@94 1972
            first_method = "check" + (object_relative and "-object" or "") + \
paul@94 1973
                                     (class_relative and "-class" or "")
paul@67 1974
paul@102 1975
        # Determine whether an unbound method is being accessed via an instance,
paul@102 1976
        # requiring a context test.
paul@102 1977
paul@102 1978
        context_test = "ignore"
paul@102 1979
paul@102 1980
        # Assignments do not employ the context.
paul@102 1981
paul@102 1982
        if is_assignment:
paul@102 1983
            pass
paul@102 1984
paul@102 1985
        # Obtain a selection of possible attributes if no unambiguous attribute
paul@102 1986
        # was identified.
paul@102 1987
paul@102 1988
        elif not attr:
paul@102 1989
paul@102 1990
            # Use previously-deduced attributes for a simple ambiguous access.
paul@102 1991
            # Otherwise, use the final attribute name to obtain possible
paul@102 1992
            # attributes.
paul@102 1993
paul@102 1994
            if len(remaining) > 1:
paul@102 1995
                attrname = remaining[-1]
paul@102 1996
paul@102 1997
                (class_types,
paul@102 1998
                 only_instance_types,
paul@102 1999
                 module_types) = self.get_types_for_attribute(attrname)
paul@102 2000
paul@102 2001
                all_accessor_kinds = set()
paul@102 2002
                all_provider_kinds = set()
paul@102 2003
paul@102 2004
                if class_types:
paul@102 2005
                    all_accessor_kinds.add("<class>")
paul@102 2006
                    all_accessor_kinds.add("<instance>")
paul@102 2007
                    all_provider_kinds.add("<class>")
paul@102 2008
                if only_instance_types:
paul@102 2009
                    all_accessor_kinds.add("<instance>")
paul@102 2010
                    all_provider_kinds.add("<instance>")
paul@102 2011
                if module_types:
paul@102 2012
                    all_accessor_kinds.add("<module>")
paul@102 2013
                    all_provider_kinds.add("<module>")
paul@102 2014
paul@102 2015
                attrs = set()
paul@102 2016
                for type in combine_types(class_types, only_instance_types, module_types):
paul@102 2017
                    attrs.update(self.importer.get_attributes(type, attrname))
paul@102 2018
paul@102 2019
            always_unbound = True
paul@102 2020
            have_function = False
paul@102 2021
            have_var = False
paul@102 2022
paul@102 2023
            # Determine whether all attributes are unbound methods and whether
paul@102 2024
            # functions or unidentified attributes occur.
paul@102 2025
paul@102 2026
            for attr in attrs:
paul@102 2027
                always_unbound = always_unbound and attr.has_kind("<function>") and attr.name_parent() == attr.parent()
paul@102 2028
                have_function = have_function or attr.has_kind("<function>")
paul@102 2029
                have_var = have_var or attr.has_kind("<var>")
paul@102 2030
paul@102 2031
            # Test for class-via-instance accesses.
paul@102 2032
paul@102 2033
            if accessor_kind == "<instance>" and \
paul@102 2034
               provider_kind == "<class>":
paul@102 2035
paul@102 2036
                if always_unbound:
paul@102 2037
                    context_test = "replace"
paul@102 2038
                else:
paul@102 2039
                    context_test = "test"
paul@102 2040
paul@102 2041
            # Test for the presence of class-via-instance accesses.
paul@102 2042
paul@102 2043
            elif "<instance>" in accessor_kinds and \
paul@102 2044
                 "<class>" in provider_kinds and \
paul@102 2045
                 (have_function or have_var):
paul@102 2046
paul@102 2047
                context_test = "test"
paul@102 2048
paul@102 2049
        # With an unambiguous attribute, determine whether a test is needed.
paul@102 2050
paul@102 2051
        elif accessor_kind == "<instance>" and \
paul@102 2052
             provider_kind == "<class>" and \
paul@102 2053
             (attr.has_kind("<var>") or
paul@102 2054
              attr.has_kind("<function>") and
paul@102 2055
              attr.name_parent() == attr.parent()):
paul@102 2056
paul@102 2057
            if attr.has_kind("<var>"):
paul@102 2058
                context_test = "test"
paul@102 2059
            else:
paul@102 2060
                context_test = "replace"
paul@102 2061
paul@102 2062
        # With an unambiguous attribute with ambiguity in the access method,
paul@102 2063
        # generate a test.
paul@102 2064
paul@102 2065
        elif "<instance>" in accessor_kinds and \
paul@102 2066
             "<class>" in provider_kinds and \
paul@102 2067
             (attr.has_kind("<var>") or
paul@102 2068
              attr.has_kind("<function>") and
paul@102 2069
              attr.name_parent() == attr.parent()):
paul@102 2070
paul@102 2071
            context_test = "test"
paul@102 2072
paul@75 2073
        # Determine the nature of the context.
paul@75 2074
paul@102 2075
        context = context_test == "ignore" and "unset" or \
paul@100 2076
                  len(traversed + remaining) == 1 and \
paul@100 2077
                      (base and "base" or "original-accessor") or \
paul@100 2078
                  "final-accessor"
paul@77 2079
paul@102 2080
        return name, test, test_type, base, traversed, traversal_modes, remaining, context, context_test, first_method, final_method, origin
paul@65 2081
paul@44 2082
# vim: tabstop=4 expandtab shiftwidth=4