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refactor.py
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# Copyright 2006 Google, Inc. All Rights Reserved. # Licensed to PSF under a Contributor Agreement. """Refactoring framework. Used as a main program, this can refactor any number of files and/or recursively descend down directories. Imported as a module, this provides infrastructure to write your own refactoring tool. """ __author__ = "Guido van Rossum <guido@python.org>" # Python imports import os import sys import logging import operator import collections import io from itertools import chain # Local imports from .pgen2 import driver, tokenize, token from .fixer_util import find_root from . import pytree, pygram from . import btm_matcher as bm def get_all_fix_names(fixer_pkg, remove_prefix=True): """Return a sorted list of all available fix names in the given package.""" pkg = __import__(fixer_pkg, [], [], ["*"]) fixer_dir = os.path.dirname(pkg.__file__) fix_names = [] for name in sorted(os.listdir(fixer_dir)): if name.startswith("fix_") and name.endswith(".py"): if remove_prefix: name = name[4:] fix_names.append(name[:-3]) return fix_names class _EveryNode(Exception): pass def _get_head_types(pat): """ Accepts a pytree Pattern Node and returns a set of the pattern types which will match first. """ if isinstance(pat, (pytree.NodePattern, pytree.LeafPattern)): # NodePatters must either have no type and no content # or a type and content -- so they don't get any farther # Always return leafs if pat.type is None: raise _EveryNode return {pat.type} if isinstance(pat, pytree.NegatedPattern): if pat.content: return _get_head_types(pat.content) raise _EveryNode # Negated Patterns don't have a type if isinstance(pat, pytree.WildcardPattern): # Recurse on each node in content r = set() for p in pat.content: for x in p: r.update(_get_head_types(x)) return r raise Exception("Oh no! I don't understand pattern %s" %(pat)) def _get_headnode_dict(fixer_list): """ Accepts a list of fixers and returns a dictionary of head node type --> fixer list. """ head_nodes = collections.defaultdict(list) every = [] for fixer in fixer_list: if fixer.pattern: try: heads = _get_head_types(fixer.pattern) except _EveryNode: every.append(fixer) else: for node_type in heads: head_nodes[node_type].append(fixer) else: if fixer._accept_type is not None: head_nodes[fixer._accept_type].append(fixer) else: every.append(fixer) for node_type in chain(pygram.python_grammar.symbol2number.values(), pygram.python_grammar.tokens): head_nodes[node_type].extend(every) return dict(head_nodes) def get_fixers_from_package(pkg_name): """ Return the fully qualified names for fixers in the package pkg_name. """ return [pkg_name + "." + fix_name for fix_name in get_all_fix_names(pkg_name, False)] def _identity(obj): return obj if sys.version_info < (3, 0): import codecs _open_with_encoding = codecs.open # codecs.open doesn't translate newlines sadly. def _from_system_newlines(input): return input.replace("\r\n", "\n") def _to_system_newlines(input): if os.linesep != "\n": return input.replace("\n", os.linesep) else: return input else: _open_with_encoding = open _from_system_newlines = _identity _to_system_newlines = _identity def _detect_future_features(source): have_docstring = False gen = tokenize.generate_tokens(io.StringIO(source).readline) def advance(): tok = next(gen) return tok[0], tok[1] ignore = frozenset({token.NEWLINE, tokenize.NL, token.COMMENT}) features = set() try: while True: tp, value = advance() if tp in ignore: continue elif tp == token.STRING: if have_docstring: break have_docstring = True elif tp == token.NAME and value == "from": tp, value = advance() if tp != token.NAME or value != "__future__": break tp, value = advance() if tp != token.NAME or value != "import": break tp, value = advance() if tp == token.OP and value == "(": tp, value = advance() while tp == token.NAME: features.add(value) tp, value = advance() if tp != token.OP or value != ",": break tp, value = advance() else: break except StopIteration: pass return frozenset(features) class FixerError(Exception): """A fixer could not be loaded.""" class RefactoringTool(object): _default_options = {"print_function" : False, "write_unchanged_files" : False} CLASS_PREFIX = "Fix" # The prefix for fixer classes FILE_PREFIX = "fix_" # The prefix for modules with a fixer within def __init__(self, fixer_names, options=None, explicit=None): """Initializer. Args: fixer_names: a list of fixers to import options: a dict with configuration. explicit: a list of fixers to run even if they are explicit. """ self.fixers = fixer_names self.explicit = explicit or [] self.options = self._default_options.copy() if options is not None: self.options.update(options) if self.options["print_function"]: self.grammar = pygram.python_grammar_no_print_statement else: self.grammar = pygram.python_grammar # When this is True, the refactor*() methods will call write_file() for # files processed even if they were not changed during refactoring. If # and only if the refactor method's write parameter was True. self.write_unchanged_files = self.options.get("write_unchanged_files") self.errors = [] self.logger = logging.getLogger("RefactoringTool") self.fixer_log = [] self.wrote = False self.driver = driver.Driver(self.grammar, convert=pytree.convert, logger=self.logger) self.pre_order, self.post_order = self.get_fixers() self.files = [] # List of files that were or should be modified self.BM = bm.BottomMatcher() self.bmi_pre_order = [] # Bottom Matcher incompatible fixers self.bmi_post_order = [] for fixer in chain(self.post_order, self.pre_order): if fixer.BM_compatible: self.BM.add_fixer(fixer) # remove fixers that will be handled by the bottom-up # matcher elif fixer in self.pre_order: self.bmi_pre_order.append(fixer) elif fixer in self.post_order: self.bmi_post_order.append(fixer) self.bmi_pre_order_heads = _get_headnode_dict(self.bmi_pre_order) self.bmi_post_order_heads = _get_headnode_dict(self.bmi_post_order) def get_fixers(self): """Inspects the options to load the requested patterns and handlers. Returns: (pre_order, post_order), where pre_order is the list of fixers that want a pre-order AST traversal, and post_order is the list that want post-order traversal. """ pre_order_fixers = [] post_order_fixers = [] for fix_mod_path in self.fixers: mod = __import__(fix_mod_path, {}, {}, ["*"]) fix_name = fix_mod_path.rsplit(".", 1)[-1] if fix_name.startswith(self.FILE_PREFIX): fix_name = fix_name[len(self.FILE_PREFIX):] parts = fix_name.split("_") class_name = self.CLASS_PREFIX + "".join([p.title() for p in parts]) try: fix_class = getattr(mod, class_name) except AttributeError: raise FixerError("Can't find %s.%s" % (fix_name, class_name)) fixer = fix_class(self.options, self.fixer_log) if fixer.explicit and self.explicit is not True and \ fix_mod_path not in self.explicit: self.log_message("Skipping optional fixer: %s", fix_name) continue self.log_debug("Adding transformation: %s", fix_name) if fixer.order == "pre": pre_order_fixers.append(fixer) elif fixer.order == "post": post_order_fixers.append(fixer) else: raise FixerError("Illegal fixer order: %r" % fixer.order) key_func = operator.attrgetter("run_order") pre_order_fixers.sort(key=key_func) post_order_fixers.sort(key=key_func) return (pre_order_fixers, post_order_fixers) def log_error(self, msg, *args, **kwds): """Called when an error occurs.""" raise def log_message(self, msg, *args): """Hook to log a message.""" if args: msg = msg % args self.logger.info(msg) def log_debug(self, msg, *args): if args: msg = msg % args self.logger.debug(msg) def print_output(self, old_text, new_text, filename, equal): """Called with the old version, new version, and filename of a refactored file.""" pass def refactor(self, items, write=False, doctests_only=False): """Refactor a list of files and directories.""" for dir_or_file in items: if os.path.isdir(dir_or_file): self.refactor_dir(dir_or_file, write, doctests_only) else: self.refactor_file(dir_or_file, write, doctests_only) def refactor_dir(self, dir_name, write=False, doctests_only=False): """Descends down a directory and refactor every Python file found. Python files are assumed to have a .py extension. Files and subdirectories starting with '.' are skipped. """ py_ext = os.extsep + "py" for dirpath, dirnames, filenames in os.walk(dir_name): self.log_debug("Descending into %s", dirpath) dirnames.sort() filenames.sort() for name in filenames: if (not name.startswith(".") and os.path.splitext(name)[1] == py_ext): fullname = os.path.join(dirpath, name) self.refactor_file(fullname, write, doctests_only) # Modify dirnames in-place to remove subdirs with leading dots dirnames[:] = [dn for dn in dirnames if not dn.startswith(".")] def _read_python_source(self, filename): """ Do our best to decode a Python source file correctly. """ try: f = open(filename, "rb") except OSError as err: self.log_error("Can't open %s: %s", filename, err) return None, None try: encoding = tokenize.detect_encoding(f.readline)[0] finally: f.close() with _open_with_encoding(filename, "r", encoding=encoding) as f: return _from_system_newlines(f.read()), encoding def refactor_file(self, filename, write=False, doctests_only=False): """Refactors a file.""" input, encoding = self._read_python_source(filename) if input is None: # Reading the file failed. return input += "\n" # Silence certain parse errors if doctests_only: self.log_debug("Refactoring doctests in %s", filename) output = self.refactor_docstring(input, filename) if self.write_unchanged_files or output != input: self.processed_file(output, filename, input, write, encoding) else: self.log_debug("No doctest changes in %s", filename) else: tree = self.refactor_string(input, filename) if self.write_unchanged_files or (tree and tree.was_changed): # The [:-1] is to take off the \n we added earlier self.processed_file(str(tree)[:-1], filename, write=write, encoding=encoding) else: self.log_debug("No changes in %s", filename) def refactor_string(self, data, name): """Refactor a given input string. Args: data: a string holding the code to be refactored. name: a human-readable name for use in error/log messages. Returns: An AST corresponding to the refactored input stream; None if there were errors during the parse. """ features = _detect_future_features(data) if "print_function" in features: self.driver.grammar = pygram.python_grammar_no_print_statement try: tree = self.driver.parse_string(data) except Exception as err: self.log_error("Can't parse %s: %s: %s", name, err.__class__.__name__, err) return finally: self.driver.grammar = self.grammar tree.future_features = features self.log_debug("Refactoring %s", name) self.refactor_tree(tree, name) return tree def refactor_stdin(self, doctests_only=False): input = sys.stdin.read() if doctests_only: self.log_debug("Refactoring doctests in stdin") output = self.refactor_docstring(input, "<stdin>") if self.write_unchanged_files or output != input: self.processed_file(output, "<stdin>", input) else: self.log_debug("No doctest changes in stdin") else: tree = self.refactor_string(input, "<stdin>") if self.write_unchanged_files or (tree and tree.was_changed): self.processed_file(str(tree), "<stdin>", input) else: self.log_debug("No changes in stdin") def refactor_tree(self, tree, name): """Refactors a parse tree (modifying the tree in place). For compatible patterns the bottom matcher module is used. Otherwise the tree is traversed node-to-node for matches. Args: tree: a pytree.Node instance representing the root of the tree to be refactored. name: a human-readable name for this tree. Returns: True if the tree was modified, False otherwise. """ for fixer in chain(self.pre_order, self.post_order): fixer.start_tree(tree, name) #use traditional matching for the incompatible fixers self.traverse_by(self.bmi_pre_order_heads, tree.pre_order()) self.traverse_by(self.bmi_post_order_heads, tree.post_order()) # obtain a set of candidate nodes match_set = self.BM.run(tree.leaves()) while any(match_set.values()): for fixer in self.BM.fixers: if fixer in match_set and match_set[fixer]: #sort by depth; apply fixers from bottom(of the AST) to top match_set[fixer].sort(key=pytree.Base.depth, reverse=True) if fixer.keep_line_order: #some fixers(eg fix_imports) must be applied #with the original file's line order match_set[fixer].sort(key=pytree.Base.get_lineno) for node in list(match_set[fixer]): if node in match_set[fixer]: match_set[fixer].remove(node) try: find_root(node) except ValueError: # this node has been cut off from a # previous transformation ; skip continue if node.fixers_applied and fixer in node.fixers_applied: # do not apply the same fixer again continue results = fixer.match(node) if results: new = fixer.transform(node, results) if new is not None: node.replace(new) #new.fixers_applied.append(fixer) for node in new.post_order(): # do not apply the fixer again to # this or any subnode if not node.fixers_applied: node.fixers_applied = [] node.fixers_applied.append(fixer) # update the original match set for # the added code new_matches = self.BM.run(new.leaves()) for fxr in new_matches: if not fxr in match_set: match_set[fxr]=[] match_set[fxr].extend(new_matches[fxr]) for fixer in chain(self.pre_order, self.post_order): fixer.finish_tree(tree, name) return tree.was_changed def traverse_by(self, fixers, traversal): """Traverse an AST, applying a set of fixers to each node. This is a helper method for refactor_tree(). Args: fixers: a list of fixer instances. traversal: a generator that yields AST nodes. Returns: None """ if not fixers: return for node in traversal: for fixer in fixers[node.type]: results = fixer.match(node) if results: new = fixer.transform(node, results) if new is not None: node.replace(new) node = new def processed_file(self, new_text, filename, old_text=None, write=False, encoding=None): """ Called when a file has been refactored and there may be changes. """ self.files.append(filename) if old_text is None: old_text = self._read_python_source(filename)[0] if old_text is None: return equal = old_text == new_text self.print_output(old_text, new_text, filename, equal) if equal: self.log_debug("No changes to %s", filename) if not self.write_unchanged_files: return if write: self.write_file(new_text, filename, old_text, encoding) else: self.log_debug("Not writing changes to %s", filename) def write_file(self, new_text, filename, old_text, encoding=None): """Writes a string to a file. It first shows a unified diff between the old text and the new text, and then rewrites the file; the latter is only done if the write option is set. """ try: f = _open_with_encoding(filename, "w", encoding=encoding) except OSError as err: self.log_error("Can't create %s: %s", filename, err) return try: f.write(_to_system_newlines(new_text)) except OSError as err: self.log_error("Can't write %s: %s", filename, err) finally: f.close() self.log_debug("Wrote changes to %s", filename) self.wrote = True PS1 = ">>> " PS2 = "... " def refactor_docstring(self, input, filename): """Refactors a docstring, looking for doctests. This returns a modified version of the input string. It looks for doctests, which start with a ">>>" prompt, and may be continued with "..." prompts, as long as the "..." is indented the same as the ">>>". (Unfortunately we can't use the doctest module's parser, since, like most parsers, it is not geared towards preserving the original source.) """ result = [] block = None block_lineno = None indent = None lineno = 0 for line in input.splitlines(keepends=True): lineno += 1 if line.lstrip().startswith(self.PS1): if block is not None: result.extend(self.refactor_doctest(block, block_lineno, indent, filename)) block_lineno = lineno block = [line] i = line.find(self.PS1) indent = line[:i] elif (indent is not None and (line.startswith(indent + self.PS2) or line == indent + self.PS2.rstrip() + "\n")): block.append(line) else: if block is not None: result.extend(self.refactor_doctest(block, block_lineno, indent, filename)) block = None indent = None result.append(line) if block is not None: result.extend(self.refactor_doctest(block, block_lineno, indent, filename)) return "".join(result) def refactor_doctest(self, block, lineno, indent, filename): """Refactors one doctest. A doctest is given as a block of lines, the first of which starts with ">>>" (possibly indented), while the remaining lines start with "..." (identically indented). """ try: tree = self.parse_block(block, lineno, indent) except Exception as err: if self.logger.isEnabledFor(logging.DEBUG): for line in block: self.log_debug("Source: %s", line.rstrip("\n")) self.log_error("Can't parse docstring in %s line %s: %s: %s", filename, lineno, err.__class__.__name__, err) return block if self.refactor_tree(tree, filename): new = str(tree).splitlines(keepends=True) # Undo the adjustment of the line numbers in wrap_toks() below. clipped, new = new[:lineno-1], new[lineno-1:] assert clipped == ["\n"] * (lineno-1), clipped if not new[-1].endswith("\n"): new[-1] += "\n" block = [indent + self.PS1 + new.pop(0)] if new: block += [indent + self.PS2 + line for line in new] return block def summarize(self): if self.wrote: were = "were" else: were = "need to be" if not self.files: self.log_message("No files %s modified.", were) else: self.log_message("Files that %s modified:", were) for file in self.files: self.log_message(file) if self.fixer_log: self.log_message("Warnings/messages while refactoring:") for message in self.fixer_log: self.log_message(message) if self.errors: if len(self.errors) == 1: self.log_message("There was 1 error:") else: self.log_message("There were %d errors:", len(self.errors)) for msg, args, kwds in self.errors: self.log_message(msg, *args, **kwds) def parse_block(self, block, lineno, indent): """Parses a block into a tree. This is necessary to get correct line number / offset information in the parser diagnostics and embedded into the parse tree. """ tree = self.driver.parse_tokens(self.wrap_toks(block, lineno, indent)) tree.future_features = frozenset() return tree def wrap_toks(self, block, lineno, indent): """Wraps a tokenize stream to systematically modify start/end.""" tokens = tokenize.generate_tokens(self.gen_lines(block, indent).__next__) for type, value, (line0, col0), (line1, col1), line_text in tokens: line0 += lineno - 1 line1 += lineno - 1 # Don't bother updating the columns; this is too complicated # since line_text would also have to be updated and it would # still break for tokens spanning lines. Let the user guess # that the column numbers for doctests are relative to the # end of the prompt string (PS1 or PS2). yield type, value, (line0, col0), (line1, col1), line_text def gen_lines(self, block, indent): """Generates lines as expected by tokenize from a list of lines. This strips the first len(indent + self.PS1) characters off each line. """ prefix1 = indent + self.PS1 prefix2 = indent + self.PS2 prefix = prefix1 for line in block: if line.startswith(prefix): yield line[len(prefix):] elif line == prefix.rstrip() + "\n": yield "\n" else: raise AssertionError("line=%r, prefix=%r" % (line, prefix)) prefix = prefix2 while True: yield "" class MultiprocessingUnsupported(Exception): pass class MultiprocessRefactoringTool(RefactoringTool): def __init__(self, *args, **kwargs): super(MultiprocessRefactoringTool, self).__init__(*args, **kwargs) self.queue = None self.output_lock = None def refactor(self, items, write=False, doctests_only=False, num_processes=1): if num_processes == 1: return super(MultiprocessRefactoringTool, self).refactor( items, write, doctests_only) try: import multiprocessing except ImportError: raise MultiprocessingUnsupported if self.queue is not None: raise RuntimeError("already doing multiple processes") self.queue = multiprocessing.JoinableQueue() self.output_lock = multiprocessing.Lock() processes = [multiprocessing.Process(target=self._child) for i in range(num_processes)] try: for p in processes: p.start() super(MultiprocessRefactoringTool, self).refactor(items, write, doctests_only) finally: self.queue.join() for i in range(num_processes): self.queue.put(None) for p in processes: if p.is_alive(): p.join() self.queue = None def _child(self): task = self.queue.get() while task is not None: args, kwargs = task try: super(MultiprocessRefactoringTool, self).refactor_file( *args, **kwargs) finally: self.queue.task_done() task = self.queue.get() def refactor_file(self, *args, **kwargs): if self.queue is not None: self.queue.put((args, kwargs)) else: return super(MultiprocessRefactoringTool, self).refactor_file( *args, **kwargs)
