1.1 --- a/common.py Thu Jan 24 19:12:29 2019 +0100
1.2 +++ b/common.py Thu Jan 24 19:16:30 2019 +0100
1.3 @@ -461,8 +461,11 @@
1.4
1.5 for i, node in enumerate(n.nodes):
1.6 statements.append(
1.7 - compiler.ast.Assign([node], compiler.ast.Subscript(
1.8 - compiler.ast.Name(temp), "OP_APPLY", [compiler.ast.Const(i, str(i))]))
1.9 + compiler.ast.Assign([node], compiler.ast.CallFunc(
1.10 + compiler.ast.Getattr(compiler.ast.Name(temp),
1.11 + "__get_single_item_unchecked__",
1.12 + privileged=True),
1.13 + [compiler.ast.Const(i, str(i))]))
1.14 )
1.15
1.16 return self.process_structure_node(compiler.ast.Stmt(statements))
1.17 @@ -1597,6 +1600,10 @@
1.18
1.19 predefined_constants = "False", "None", "NotImplemented", "True"
1.20
1.21 +privileged_attributes = [
1.22 + "__get_single_item_unchecked__",
1.23 + ]
1.24 +
1.25 unary_operator_functions = {
1.26
1.27 # Unary operations.
2.1 --- a/compiler/ast.py Thu Jan 24 19:12:29 2019 +0100
2.2 +++ b/compiler/ast.py Thu Jan 24 19:16:30 2019 +0100
2.3 @@ -868,11 +868,15 @@
2.4 return "%s %s" % (self.expr, " ".join(map(str, self.quals)))
2.5
2.6 class Getattr(Node):
2.7 - def __init__(self, expr, attrname, lineno=None):
2.8 + def __init__(self, expr, attrname, lineno=None, privileged=False):
2.9 self.expr = expr
2.10 self.attrname = attrname
2.11 self.lineno = lineno
2.12
2.13 + # Support privileged internal accesses.
2.14 +
2.15 + self.privileged = privileged
2.16 +
2.17 def getChildren(self):
2.18 return self.expr, self.attrname
2.19
3.1 --- a/inspector.py Thu Jan 24 19:12:29 2019 +0100
3.2 +++ b/inspector.py Thu Jan 24 19:16:30 2019 +0100
3.3 @@ -21,7 +21,8 @@
3.4 """
3.5
3.6 from branching import BranchTracker
3.7 -from common import CommonModule, get_argnames, init_item, predefined_constants
3.8 +from common import CommonModule, get_argnames, init_item, \
3.9 + predefined_constants, privileged_attributes
3.10 from modules import BasicModule, CacheWritingModule, InspectionNaming
3.11 from errors import InspectError
3.12 from referencing import Reference
3.13 @@ -358,6 +359,16 @@
3.14
3.15 "Process the given attribute access node 'n'."
3.16
3.17 + path = self.get_namespace_path()
3.18 +
3.19 + # Test for access to special privileged attributes.
3.20 +
3.21 + if isinstance(n, compiler.ast.Getattr) and \
3.22 + n.attrname in privileged_attributes and not n.privileged:
3.23 +
3.24 + raise InspectError("Attribute %s is accessed by an unprivileged operation." %
3.25 + n.attrname, path, n)
3.26 +
3.27 # Obtain any completed chain and return the reference to it.
3.28
3.29 name_ref = self.process_attribute_chain(n)
3.30 @@ -372,8 +383,6 @@
3.31 # either being name-based and thus an access rooted on a name, or being
3.32 # based on some other node and thus an anonymous access of some kind.
3.33
3.34 - path = self.get_namespace_path()
3.35 -
3.36 # Start with the the full attribute chain.
3.37
3.38 remaining = self.attrs
4.1 --- a/lib/__builtins__/list.py Thu Jan 24 19:12:29 2019 +0100
4.2 +++ b/lib/__builtins__/list.py Thu Jan 24 19:16:30 2019 +0100
4.3 @@ -3,7 +3,7 @@
4.4 """
4.5 List objects.
4.6
4.7 -Copyright (C) 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk>
4.8 +Copyright (C) 2015, 2016, 2017, 2018 Paul Boddie <paul@boddie.org.uk>
4.9
4.10 This program is free software; you can redistribute it and/or modify it under
4.11 the terms of the GNU General Public License as published by the Free Software
4.12 @@ -20,11 +20,11 @@
4.13 """
4.14
4.15 from __builtins__.iteration.iterator import itemiterator
4.16 -from __builtins__.sequence import sequence, _get_absolute_index
4.17 +from __builtins__.sequence import unpackable, _get_absolute_index
4.18 from native import list_append, list_concat, list_element, list_init, \
4.19 list_len, list_nonempty, list_setelement, list_setsize
4.20
4.21 -class list(sequence):
4.22 +class list(unpackable):
4.23
4.24 "Implementation of list."
4.25
5.1 --- a/lib/__builtins__/sequence.py Thu Jan 24 19:12:29 2019 +0100
5.2 +++ b/lib/__builtins__/sequence.py Thu Jan 24 19:16:30 2019 +0100
5.3 @@ -20,7 +20,7 @@
5.4 """
5.5
5.6 from __builtins__.int import maxint
5.7 -from native import isinstance as _isinstance, is_int
5.8 +from native import isinstance as _isinstance, is_int, list_element
5.9
5.10 class itemaccess:
5.11
5.12 @@ -255,6 +255,22 @@
5.13
5.14 # __iter__(self)
5.15
5.16 +class unpackable(sequence):
5.17 +
5.18 + "Class for list and tuple unpacking."
5.19 +
5.20 + def __get_single_item_unchecked__(self, index):
5.21 +
5.22 + """
5.23 + This method is provided by a privileged attribute recorded in the common
5.24 + module in the toolchain. Normal programs should not be able to access
5.25 + it.
5.26 + """
5.27 +
5.28 + # NOTE: This uses implementation-specific access.
5.29 +
5.30 + return list_element(self.__data__, index)
5.31 +
5.32 def _get_absolute_index(index, length):
5.33
5.34 """
6.1 --- a/lib/__builtins__/tuple.py Thu Jan 24 19:12:29 2019 +0100
6.2 +++ b/lib/__builtins__/tuple.py Thu Jan 24 19:16:30 2019 +0100
6.3 @@ -20,12 +20,12 @@
6.4 """
6.5
6.6 from __builtins__.iteration.iterator import itemiterator
6.7 -from __builtins__.sequence import hashable, sequence
6.8 +from __builtins__.sequence import hashable, unpackable
6.9 from native import tuple_init, \
6.10 list_element, list_len, list_setsize, list_setelement, \
6.11 isinstance as _isinstance
6.12
6.13 -class tuple(sequence, hashable):
6.14 +class tuple(unpackable, hashable):
6.15
6.16 "Implementation of tuple."
6.17
6.18 @@ -66,7 +66,7 @@
6.19 'step'.
6.20 """
6.21
6.22 - return tuple(get_using(sequence.__getslice__, self)(start, end, step))
6.23 + return tuple(get_using(unpackable.__getslice__, self)(start, end, step))
6.24
6.25 def __len__(self):
6.26
7.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
7.2 +++ b/tests/tuple_unpack_bad.py Thu Jan 24 19:16:30 2019 +0100
7.3 @@ -0,0 +1,9 @@
7.4 +def good(t):
7.5 + a, b, c = t
7.6 +
7.7 +def bad(t):
7.8 + a = t.__get_single_item_unchecked__(0)
7.9 +
7.10 +t = 1, 2, 3
7.11 +good(t)
7.12 +bad(t)