1. Tarek Ziadé
  2. distribute

Source

distribute / _markerlib / markers.py

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Daniel Holth 587e21e 













Daniel Holth b62968c 
Daniel Holth 587e21e 



Arfrever Frehtes… db387a6 
Daniel Holth 587e21e 

























Arfrever Frehtes… db387a6 
Daniel Holth 587e21e 

Arfrever Frehtes… db387a6 






Daniel Holth 587e21e 



Arfrever Frehtes… db387a6 
Daniel Holth 587e21e 
Arfrever Frehtes… db387a6 

Daniel Holth 587e21e 

Arfrever Frehtes… db387a6 

Daniel Holth 587e21e 

Arfrever Frehtes… db387a6 
Daniel Holth 587e21e 

































# -*- coding: utf-8 -*-
"""Interpret PEP 345 environment markers.

EXPR [in|==|!=|not in] EXPR [or|and] ...

where EXPR belongs to any of those:

    python_version = '%s.%s' % (sys.version_info[0], sys.version_info[1])
    python_full_version = sys.version.split()[0]
    os.name = os.name
    sys.platform = sys.platform
    platform.version = platform.version()
    platform.machine = platform.machine()
    platform.python_implementation = platform.python_implementation()
    a free string, like '2.6', or 'win32'
"""

__all__ = ['default_environment', 'compile', 'interpret']

import ast
import os
import platform
import sys
import weakref

_builtin_compile = compile

from platform import python_implementation

# restricted set of variables
_VARS = {'sys.platform': sys.platform,
         'python_version': '%s.%s' % sys.version_info[:2],
         # FIXME parsing sys.platform is not reliable, but there is no other
         # way to get e.g. 2.7.2+, and the PEP is defined with sys.version
         'python_full_version': sys.version.split(' ', 1)[0],
         'os.name': os.name,
         'platform.version': platform.version(),
         'platform.machine': platform.machine(),
         'platform.python_implementation': python_implementation(),
         'extra': None # wheel extension
        }

def default_environment():
    """Return copy of default PEP 385 globals dictionary."""
    return dict(_VARS)

class ASTWhitelist(ast.NodeTransformer):
    def __init__(self, statement):
        self.statement = statement # for error messages

    ALLOWED = (ast.Compare, ast.BoolOp, ast.Attribute, ast.Name, ast.Load, ast.Str)
    # Bool operations
    ALLOWED += (ast.And, ast.Or)
    # Comparison operations
    ALLOWED += (ast.Eq, ast.Gt, ast.GtE, ast.In, ast.Is, ast.IsNot, ast.Lt, ast.LtE, ast.NotEq, ast.NotIn)

    def visit(self, node):
        """Ensure statement only contains allowed nodes."""
        if not isinstance(node, self.ALLOWED):
            raise SyntaxError('Not allowed in environment markers.\n%s\n%s' %
                               (self.statement,
                               (' ' * node.col_offset) + '^'))
        return ast.NodeTransformer.visit(self, node)

    def visit_Attribute(self, node):
        """Flatten one level of attribute access."""
        new_node = ast.Name("%s.%s" % (node.value.id, node.attr), node.ctx)
        return ast.copy_location(new_node, node)

def parse_marker(marker):
    tree = ast.parse(marker, mode='eval')
    new_tree = ASTWhitelist(marker).generic_visit(tree)
    return new_tree

def compile_marker(parsed_marker):
    return _builtin_compile(parsed_marker, '<environment marker>', 'eval',
                   dont_inherit=True)

_cache = weakref.WeakValueDictionary()

def compile(marker):
    """Return compiled marker as a function accepting an environment dict."""
    try:
        return _cache[marker]
    except KeyError:
        pass
    if not marker.strip():
        def marker_fn(environment=None, override=None):
            """"""
            return True
    else:
        compiled_marker = compile_marker(parse_marker(marker))
        def marker_fn(environment=None, override=None):
            """override updates environment"""
            if override is None:
                override = {}
            if environment is None:
                environment = default_environment()
            environment.update(override)
            return eval(compiled_marker, environment)
    marker_fn.__doc__ = marker
    _cache[marker] = marker_fn
    return _cache[marker]

def interpret(marker, environment=None):
    return compile(marker)(environment)