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scripts/i18n/src/mytracks/history.py

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+'''
+Module which brings history information about files from Mercurial.
+
+@author: Rodrigo Damazio
+'''
+
+import re
+import subprocess
+
+REVISION_REGEX = re.compile(r'(?P<hash>[0-9a-f]{12}):.*')
+
+def _GetOutputLines(args):
+  '''
+  Runs an external process and returns its output as a list of lines.
+
+  @param args: the arguments to run
+  '''
+  process = subprocess.Popen(args,
+                             stdout=subprocess.PIPE,
+                             universal_newlines = True,
+                             shell = False)
+  output = process.communicate()[0]
+  return output.splitlines()
+
+
+def FillMercurialRevisions(filename, parsed_file):
+  '''
+  Fills the revs attribute of all strings in the given parsed file with
+  a list of revisions that touched the lines corresponding to that string.
+  
+  @param filename: the name of the file to get history for
+  @param parsed_file: the parsed file to modify
+  '''
+  # Take output of hg annotate to get revision of each line
+  output_lines = _GetOutputLines(['hg', 'annotate', '-c', filename])
+
+  # Create a map of line -> revision (key is list index, line 0 doesn't exist)
+  line_revs = ['dummy']
+  for line in output_lines:
+    rev_match = REVISION_REGEX.match(line)
+    if not rev_match:
+      raise 'Unexpected line of output from hg: %s' % line
+    rev_hash = rev_match.group('hash')
+    line_revs.append(rev_hash)
+
+  for str in parsed_file.itervalues():
+    # Get the lines that correspond to each string
+    start_line = str['startLine']
+    end_line = str['endLine']
+
+    # Get the revisions that touched those lines
+    revs = []
+    for line_number in range(start_line, end_line + 1):
+      revs.append(line_revs[line_number])
+
+    # Merge with any revisions that were already there
+    # (for explict revision specification)
+    if 'revs' in str:
+      revs += str['revs']
+
+    # Assign the revisions to the string
+    str['revs'] = frozenset(revs)
+
+def DoesRevisionSuperceed(filename, rev1, rev2):
+  '''
+  Tells whether a revision superceeds another.
+  This essentially means that the older revision is an ancestor of the newer
+  one.
+  This also returns True if the two revisions are the same.
+
+  @param rev1: the revision that may be superceeding the other
+  @param rev2: the revision that may be superceeded
+  @return: True if rev1 superceeds rev2 or they're the same
+  '''
+  if rev1 == rev2:
+    return True
+
+  # TODO: Add filename
+  args = ['hg', 'log', '-r', 'ancestors(%s)' % rev1, '--template', '{node|short}\n', filename]
+  output_lines = _GetOutputLines(args)
+
+  return rev2 in output_lines
+
+def NewestRevision(filename, rev1, rev2):
+  '''
+  Returns which of two revisions is closest to the head of the repository.
+  If none of them is the ancestor of the other, then we return either one.
+
+  @param rev1: the first revision
+  @param rev2: the second revision
+  '''
+  if DoesRevisionSuperceed(filename, rev1, rev2):
+    return rev1
+  return rev2