Remove contents of grit's SVN repository.

grit/gather/chrome_scaled_image.py

-#!/usr/bin/env python
-# Copyright (c) 2012 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.
-
-'''Gatherer for <structure type="chrome_scaled_image">.
-'''
-
-import os
-import struct
-
-from grit import exception
-from grit import lazy_re
-from grit import util
-from grit.gather import interface
-
-
-_PNG_SCALE_CHUNK = '\0\0\0\0csCl\xc1\x30\x60\x4d'
-
-
-def _RescaleImage(data, from_scale, to_scale):
-  if from_scale != to_scale:
-    assert from_scale == 100
-    # Rather than rescaling the image we add a custom chunk directing Chrome to
-    # rescale it on load. Just append it to the PNG data since
-    # _MoveSpecialChunksToFront will move it later anyway.
-    data += _PNG_SCALE_CHUNK
-  return data
-
-
-_PNG_MAGIC = '\x89PNG\r\n\x1a\n'
-
-'''Mandatory first chunk in order for the png to be valid.'''
-_FIRST_CHUNK = 'IHDR'
-
-'''Special chunks to move immediately after the IHDR chunk. (so that the PNG
-remains valid.)
-'''
-_SPECIAL_CHUNKS = frozenset('csCl npTc'.split())
-
-'''Any ancillary chunk not in this list is deleted from the PNG.'''
-_ANCILLARY_CHUNKS_TO_LEAVE = frozenset(
-    'bKGD cHRM gAMA iCCP pHYs sBIT sRGB tRNS'.split())
-
-
-def _MoveSpecialChunksToFront(data):
-  '''Move special chunks immediately after the IHDR chunk (so that the PNG
-  remains valid). Also delete ancillary chunks that are not on our whitelist.
-  '''
-  first = [_PNG_MAGIC]
-  special_chunks = []
-  rest = []
-  for chunk in _ChunkifyPNG(data):
-    type = chunk[4:8]
-    critical = type < 'a'
-    if type == _FIRST_CHUNK:
-      first.append(chunk)
-    elif type in _SPECIAL_CHUNKS:
-      special_chunks.append(chunk)
-    elif critical or type in _ANCILLARY_CHUNKS_TO_LEAVE:
-      rest.append(chunk)
-  return ''.join(first + special_chunks + rest)
-
-
-def _ChunkifyPNG(data):
-  '''Given a PNG image, yield its chunks in order.'''
-  assert data.startswith(_PNG_MAGIC)
-  pos = 8
-  while pos != len(data):
-    length = 12 + struct.unpack_from('>I', data, pos)[0]
-    assert 12 <= length <= len(data) - pos
-    yield data[pos:pos+length]
-    pos += length
-
-
-def _MakeBraceGlob(strings):
-  '''Given ['foo', 'bar'], return '{foo,bar}', for error reporting.
-  '''
-  if len(strings) == 1:
-    return strings[0]
-  else:
-    return '{' + ','.join(strings) + '}'
-
-
-class ChromeScaledImage(interface.GathererBase):
-  '''Represents an image that exists in multiple layout variants
-  (e.g. "default", "touch") and multiple scale variants
-  (e.g. "100_percent", "200_percent").
-  '''
-
-  split_context_re_ = lazy_re.compile(r'(.+)_(\d+)_percent\Z')
-
-  def _FindInputFile(self):
-    output_context = self.grd_node.GetRoot().output_context
-    match = self.split_context_re_.match(output_context)
-    if not match:
-      raise exception.MissingMandatoryAttribute(
-          'All <output> nodes must have an appropriate context attribute'
-          ' (e.g. context="touch_200_percent")')
-    req_layout, req_scale = match.group(1), int(match.group(2))
-
-    layouts = [req_layout]
-    try_default_layout = self.grd_node.GetRoot().fallback_to_default_layout
-    if try_default_layout and 'default' not in layouts:
-      layouts.append('default')
-
-    # TODO(tdanderson): Search in descending order of all image scales
-    #                   instead of immediately falling back to 100.
-    #                   See crbug.com/503643.
-    scales = [req_scale]
-    try_low_res = self.grd_node.FindBooleanAttribute(
-        'fallback_to_low_resolution', default=False, skip_self=False)
-    if try_low_res and 100 not in scales:
-      scales.append(100)
-
-    for layout in layouts:
-      for scale in scales:
-        dir = '%s_%s_percent' % (layout, scale)
-        path = os.path.join(dir, self.rc_file)
-        if os.path.exists(self.grd_node.ToRealPath(path)):
-          return path, scale, req_scale
-
-    if not try_default_layout:
-      # The file was not found in the specified output context and it was
-      # explicitly indicated that the default context should not be searched
-      # as a fallback, so return an empty path.
-      return None, 100, req_scale
-
-    # The file was found in neither the specified context nor the default
-    # context, so raise an exception.
-    dir = "%s_%s_percent" % (_MakeBraceGlob(layouts),
-                             _MakeBraceGlob(map(str, scales)))
-    raise exception.FileNotFound(
-        'Tried ' + self.grd_node.ToRealPath(os.path.join(dir, self.rc_file)))
-
-  def GetInputPath(self):
-    path, scale, req_scale = self._FindInputFile()
-    return path
-
-  def Parse(self):
-    pass
-
-  def GetTextualIds(self):
-    return [self.extkey]
-
-  def GetData(self, *args):
-    path, scale, req_scale = self._FindInputFile()
-    if path is None:
-      return None
-
-    data = util.ReadFile(self.grd_node.ToRealPath(path), util.BINARY)
-    data = _RescaleImage(data, scale, req_scale)
-    data = _MoveSpecialChunksToFront(data)
-    return data
-
-  def Translate(self, *args, **kwargs):
-    return self.GetData()