Remove the review bot app.

reviewbot/handlers/policy_checklist/parser.py

-# Copyright (c) 2013 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import re
-
-import util
-
-
-CONTEXT_THRESHOLD = 12
-PROPERTY_NAME_RE = re.compile(r"^\s*'(\w+)'\s*:")
-
-
-def nmin(*args):
-  """Calculates the minimum of |args|, ignoring None entries."""
-  values = [v for v in args if v is not None]
-  return None if len(values) == 0 else min(values)
-
-
-def nmax(*args):
-  """Calculates the maximum of |args|, ignoring None entries."""
-  values = [v for v in args if v is not None]
-  return None if len(values) == 0 else max(values)
-
-
-def nadd(a, b):
-  """Calculates a + b, returning None if either a or b is None"""
-  return None if (a is None or b is None) else a + b
-
-
-def nsub(a, b):
-  """Calculates a - b, returning None if either a or b is None"""
-  return None if (a is None or b is None) else a - b
-
-
-def get_indentation_level(line):
-  """Returns the indentation level (number of leading spaces) for |line|."""
-  nspaces = len(line) - len(line.lstrip(' '))
-  return None if nspaces == 0 else nspaces
-
-
-class PolicyChangeParser(object):
-  """Parses a policy_templates.json diff to identify logical changes.
-
-  This takes a list of triples of the form (old_line, new_line, text) as
-  returned by patching.ParsePatchToLines and produces a list of dictionaries
-  describing the logical changes that have been made. The dictionaries contain
-  these keys:
-    * start: A pair (old_line, new_line) indicating where the change starts.
-    * end: A pair (old_line, new_line) indicating where the change ends.
-    * comment_pos: A pair (old_line, new_line), indicating a suitable place to
-                   put an inline comment. This is typically the line where the
-                   policy name is found in the diff.
-    * additions: Whether there have been line additions.
-    * removals: Whether there have been line removals.
-  """
-
-  def __init__(self, lines):
-    self.lines = lines
-    self.chunks_list = []
-    self.reset()
-
-  def run(self):
-    """Main parsing function.
-
-    The code goes over the diff line by line, keeping track of the current line.
-    It keeps track of the current line numbers, and where the last changes
-    happened in the old and new version of the file.
-
-    Certain events trigger start of a new logical change. These are
-    discontinuities in the cursor position and decreases of the indentation
-    level. Once a block closes, the information for that block is recorded in
-    the result list.
-    """
-    self.chunks_list = []
-    self.last_change = [None, None]
-    cursor = [None, None]
-    self.reset()
-    for (a_line, b_line, line) in self.lines:
-      # Skip comment lines.
-      if line.startswith('#'):
-        continue
-
-      # See whether the current line has a JSON property.
-      keyword = None
-      match = PROPERTY_NAME_RE.match(line)
-      if match:
-        keyword = match.group(1).lower()
-
-
-      # Check whether the current block closes.
-      line_indent = get_indentation_level(line)
-      if (self.block_indent is not None and
-            line_indent is not None and
-            line_indent < self.block_indent):
-        self.block_closed = True
-
-      # Update various cursors.
-      cursor = [nmax(a_line, cursor[0]), nmax(b_line, cursor[1])]
-      offset = nmin(nsub(cursor[0], self.last_change[0]),
-                    nsub(cursor[1], self.last_change[1]))
-
-      # Update change tracking state.
-      if a_line is not None and b_line is None:
-        self.removals = True
-        self.last_change[0] = a_line
-        self.text_changed |= any([c.isalnum() for c in line])
-      elif a_line is None and b_line is not None:
-        self.additions = True
-        self.last_change[1] = b_line
-        self.text_changed |= any([c.isalnum() for c in line])
-
-      # If the indentation block closes or the last chunk is too far away,
-      # assume a new one starts.
-      if (self.block_closed or
-          (offset is not None and (offset > CONTEXT_THRESHOLD))):
-        self.flush_chunk()
-
-      # Try to figure out block indent from properties exclusively used for
-      # policy definitions.
-      if (self.block_indent is None and
-          keyword in ('id', 'schema', 'future', 'features', 'supported_on',
-                      'example_value', 'deprecated')):
-        self.block_indent = line_indent
-
-      # Put the comment on the policy name property if we see it fly by.
-      if keyword == 'name':
-        # Filter out name labels on enum items and schemas.
-        if self.block_indent is not None and self.block_indent != line_indent:
-          pass
-        elif a_line is not None and b_line is None:
-          self.comment_pos[0] = a_line
-        elif a_line is None and b_line is not None:
-          self.comment_pos[1] = b_line
-
-      self.chunk_start = [nmin(self.last_change[0], self.chunk_start[0]),
-                          nmin(self.last_change[1], self.chunk_start[1])]
-
-    # Flush the last chunk.
-    if self.chunk_start != [None, None]:
-      self.flush_chunk()
-
-  def flush_chunk(self):
-    if self.text_changed:
-      comment_pos = [nmax(self.chunk_start[0], self.comment_pos[0]),
-                     nmax(self.chunk_start[1], self.comment_pos[1])]
-      self.chunks_list.append(
-          util.ObjectDict(
-              { 'start': self.chunk_start,
-                'end': [nadd(self.last_change[0], 1),
-                        nadd(self.last_change[1], 1)],
-                'comment_pos': comment_pos,
-                'additions': self.additions,
-                'removals': self.removals }))
-    self.reset()
-
-  def reset(self):
-    # This is called from __init__.
-    # pylint: disable=W0201
-    self.chunk_start = [None, None]
-    self.last_change = [None, None]
-    self.comment_pos = [None, None]
-    self.block_indent = None
-    self.block_closed = False
-    self.additions = False
-    self.removals = False
-    self.text_changed = False
-
-
-def parse(lines):
-  """Helper function to parse lines to a list of chunks directly."""
-  parser = PolicyChangeParser(lines)
-  parser.run()
-  return parser.chunks_list