Index: reviewbot/handlers/policy_checklist/parser.py |
=================================================================== |
--- reviewbot/handlers/policy_checklist/parser.py (revision 221173) |
+++ reviewbot/handlers/policy_checklist/parser.py (working copy) |
@@ -1,174 +0,0 @@ |
-# 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 |