128 lines
3.6 KiB
Python
128 lines
3.6 KiB
Python
# Copyright 2009 The Closure Library Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS-IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Scans a source JS file for its provided and required namespaces.
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Simple class to scan a JavaScript file and express its dependencies.
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"""
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__author__ = 'nnaze@google.com'
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import re
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_BASE_REGEX_STRING = r'^\s*goog\.%s\(\s*[\'"](.+)[\'"]\s*\)'
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_MODULE_REGEX = re.compile(_BASE_REGEX_STRING % 'module')
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_PROVIDE_REGEX = re.compile(_BASE_REGEX_STRING % 'provide')
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_REQUIRE_REGEX_STRING = (r'^\s*(?:(?:var|let|const)\s+[a-zA-Z_$][a-zA-Z0-9$_]*'
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r'\s*=\s*)?goog\.require\(\s*[\'"](.+)[\'"]\s*\)')
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_REQUIRES_REGEX = re.compile(_REQUIRE_REGEX_STRING)
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class Source(object):
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"""Scans a JavaScript source for its provided and required namespaces."""
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# Matches a "/* ... */" comment.
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# Note: We can't definitively distinguish a "/*" in a string literal without a
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# state machine tokenizer. We'll assume that a line starting with whitespace
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# and "/*" is a comment.
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_COMMENT_REGEX = re.compile(
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r"""
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^\s* # Start of a new line and whitespace
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/\* # Opening "/*"
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.*? # Non greedy match of any characters (including newlines)
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\*/ # Closing "*/""",
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re.MULTILINE | re.DOTALL | re.VERBOSE)
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def __init__(self, source):
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"""Initialize a source.
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Args:
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source: str, The JavaScript source.
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"""
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self.provides = set()
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self.requires = set()
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self.is_goog_module = False
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self._source = source
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self._ScanSource()
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def GetSource(self):
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"""Get the source as a string."""
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return self._source
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@classmethod
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def _StripComments(cls, source):
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return cls._COMMENT_REGEX.sub('', source)
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@classmethod
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def _HasProvideGoogFlag(cls, source):
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"""Determines whether the @provideGoog flag is in a comment."""
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for comment_content in cls._COMMENT_REGEX.findall(source):
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if '@provideGoog' in comment_content:
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return True
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return False
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def _ScanSource(self):
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"""Fill in provides and requires by scanning the source."""
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stripped_source = self._StripComments(self.GetSource())
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source_lines = stripped_source.splitlines()
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for line in source_lines:
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match = _PROVIDE_REGEX.match(line)
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if match:
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self.provides.add(match.group(1))
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match = _MODULE_REGEX.match(line)
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if match:
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self.provides.add(match.group(1))
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self.is_goog_module = True
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match = _REQUIRES_REGEX.match(line)
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if match:
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self.requires.add(match.group(1))
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# Closure's base file implicitly provides 'goog'.
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# This is indicated with the @provideGoog flag.
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if self._HasProvideGoogFlag(self.GetSource()):
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if len(self.provides) or len(self.requires):
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raise Exception(
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'Base file should not provide or require namespaces.')
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self.provides.add('goog')
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def GetFileContents(path):
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"""Get a file's contents as a string.
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Args:
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path: str, Path to file.
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Returns:
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str, Contents of file.
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Raises:
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IOError: An error occurred opening or reading the file.
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"""
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fileobj = open(path)
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try:
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return fileobj.read()
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finally:
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fileobj.close()
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