187 lines
6.5 KiB
Python
187 lines
6.5 KiB
Python
# Copyright 2006 Google, Inc. All Rights Reserved.
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# Licensed to PSF under a Contributor Agreement.
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"""Base class for fixers (optional, but recommended)."""
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# Python imports
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import logging
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import itertools
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# Local imports
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from .patcomp import PatternCompiler
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from . import pygram
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from .fixer_util import does_tree_import
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class BaseFix(object):
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"""Optional base class for fixers.
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The subclass name must be FixFooBar where FooBar is the result of
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removing underscores and capitalizing the words of the fix name.
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For example, the class name for a fixer named 'has_key' should be
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FixHasKey.
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"""
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PATTERN = None # Most subclasses should override with a string literal
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pattern = None # Compiled pattern, set by compile_pattern()
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pattern_tree = None # Tree representation of the pattern
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options = None # Options object passed to initializer
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filename = None # The filename (set by set_filename)
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numbers = itertools.count(1) # For new_name()
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used_names = set() # A set of all used NAMEs
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order = "post" # Does the fixer prefer pre- or post-order traversal
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explicit = False # Is this ignored by refactor.py -f all?
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run_order = 5 # Fixers will be sorted by run order before execution
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# Lower numbers will be run first.
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_accept_type = None # [Advanced and not public] This tells RefactoringTool
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# which node type to accept when there's not a pattern.
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keep_line_order = False # For the bottom matcher: match with the
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# original line order
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BM_compatible = False # Compatibility with the bottom matching
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# module; every fixer should set this
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# manually
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# Shortcut for access to Python grammar symbols
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syms = pygram.python_symbols
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def __init__(self, options, log):
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"""Initializer. Subclass may override.
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Args:
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options: an dict containing the options passed to RefactoringTool
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that could be used to customize the fixer through the command line.
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log: a list to append warnings and other messages to.
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"""
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self.options = options
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self.log = log
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self.compile_pattern()
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def compile_pattern(self):
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"""Compiles self.PATTERN into self.pattern.
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Subclass may override if it doesn't want to use
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self.{pattern,PATTERN} in .match().
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"""
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if self.PATTERN is not None:
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PC = PatternCompiler()
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self.pattern, self.pattern_tree = PC.compile_pattern(self.PATTERN,
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with_tree=True)
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def set_filename(self, filename):
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"""Set the filename.
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The main refactoring tool should call this.
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"""
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self.filename = filename
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def match(self, node):
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"""Returns match for a given parse tree node.
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Should return a true or false object (not necessarily a bool).
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It may return a non-empty dict of matching sub-nodes as
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returned by a matching pattern.
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Subclass may override.
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"""
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results = {"node": node}
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return self.pattern.match(node, results) and results
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def transform(self, node, results):
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"""Returns the transformation for a given parse tree node.
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Args:
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node: the root of the parse tree that matched the fixer.
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results: a dict mapping symbolic names to part of the match.
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Returns:
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None, or a node that is a modified copy of the
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argument node. The node argument may also be modified in-place to
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effect the same change.
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Subclass *must* override.
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"""
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raise NotImplementedError()
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def new_name(self, template="xxx_todo_changeme"):
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"""Return a string suitable for use as an identifier
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The new name is guaranteed not to conflict with other identifiers.
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"""
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name = template
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while name in self.used_names:
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name = template + str(next(self.numbers))
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self.used_names.add(name)
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return name
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def log_message(self, message):
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if self.first_log:
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self.first_log = False
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self.log.append("### In file %s ###" % self.filename)
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self.log.append(message)
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def cannot_convert(self, node, reason=None):
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"""Warn the user that a given chunk of code is not valid Python 3,
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but that it cannot be converted automatically.
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First argument is the top-level node for the code in question.
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Optional second argument is why it can't be converted.
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"""
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lineno = node.get_lineno()
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for_output = node.clone()
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for_output.prefix = ""
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msg = "Line %d: could not convert: %s"
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self.log_message(msg % (lineno, for_output))
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if reason:
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self.log_message(reason)
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def warning(self, node, reason):
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"""Used for warning the user about possible uncertainty in the
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translation.
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First argument is the top-level node for the code in question.
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Optional second argument is why it can't be converted.
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"""
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lineno = node.get_lineno()
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self.log_message("Line %d: %s" % (lineno, reason))
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def start_tree(self, tree, filename):
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"""Some fixers need to maintain tree-wide state.
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This method is called once, at the start of tree fix-up.
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tree - the root node of the tree to be processed.
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filename - the name of the file the tree came from.
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"""
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self.used_names = tree.used_names
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self.set_filename(filename)
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self.numbers = itertools.count(1)
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self.first_log = True
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def finish_tree(self, tree, filename):
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"""Some fixers need to maintain tree-wide state.
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This method is called once, at the conclusion of tree fix-up.
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tree - the root node of the tree to be processed.
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filename - the name of the file the tree came from.
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"""
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pass
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class ConditionalFix(BaseFix):
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""" Base class for fixers which not execute if an import is found. """
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# This is the name of the import which, if found, will cause the test to be skipped
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skip_on = None
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def start_tree(self, *args):
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super(ConditionalFix, self).start_tree(*args)
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self._should_skip = None
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def should_skip(self, node):
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if self._should_skip is not None:
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return self._should_skip
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pkg = self.skip_on.split(".")
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name = pkg[-1]
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pkg = ".".join(pkg[:-1])
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self._should_skip = does_tree_import(pkg, name, node)
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return self._should_skip
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