Initial source commit to grit-i18n project.

grit/format/data_pack.py

+#!/usr/bin/python2.4
+# Copyright (c) 2011 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.
+
+'''Support for formatting a data pack file used for platform agnostic resource
+files.
+'''
+
+import exceptions
+import os
+import struct
+import sys
+
+sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..'))
+from grit.format import interface
+from grit.node import include
+from grit.node import message
+from grit.node import misc
+
+
+PACK_FILE_VERSION = 4
+HEADER_LENGTH = 2 * 4 + 1  # Two uint32s. (file version, number of entries) and
+                           # one uint8 (encoding of text resources)
+BINARY, UTF8, UTF16 = range(3)
+
+class WrongFileVersion(Exception):
+  pass
+
+class DataPackContents:
+  def __init__(self, resources, encoding):
+    self.resources = resources
+    self.encoding = encoding
+
+class DataPack(interface.ItemFormatter):
+  '''Writes out the data pack file format (platform agnostic resource file).'''
+  def Format(self, item, lang='en', begin_item=True, output_dir='.'):
+    if not begin_item:
+      return ''
+
+    assert isinstance(item, misc.ReleaseNode)
+
+    nodes = DataPack.GetDataNodes(item)
+    data = {}
+    for node in nodes:
+      id, value = node.GetDataPackPair(lang, UTF8)
+      data[id] = value
+    return DataPack.WriteDataPackToString(data, UTF8)
+
+  @staticmethod
+  def GetDataNodes(item):
+    '''Returns a list of nodes that can be packed into the data pack file.'''
+    nodes = []
+    if (isinstance(item, misc.IfNode) and not item.IsConditionSatisfied()):
+      return nodes
+    if (isinstance(item, include.IncludeNode) or
+        isinstance(item, message.MessageNode)):
+      # Include this node if it wasn't marked as skipped by a whitelist.
+      if not item.WhitelistMarkedAsSkip():
+        return [item]
+      return nodes
+    for child in item.children:
+      nodes.extend(DataPack.GetDataNodes(child))
+    return nodes
+
+  @staticmethod
+  def ReadDataPack(input_file):
+    """Reads a data pack file and returns a dictionary."""
+    data = open(input_file, "rb").read()
+    original_data = data
+
+    # Read the header.
+    version, num_entries, encoding = struct.unpack("<IIB",
+                                                   data[:HEADER_LENGTH])
+    if version != PACK_FILE_VERSION:
+      print "Wrong file version in ", input_file
+      raise WrongFileVersion
+
+    resources = {}
+    if num_entries == 0:
+      return DataPackContents(resources, encoding)
+
+    # Read the index and data.
+    data = data[HEADER_LENGTH:]
+    kIndexEntrySize = 2 + 4  # Each entry is a uint16 and a uint32.
+    for _ in range(num_entries):
+      id, offset = struct.unpack("<HI", data[:kIndexEntrySize])
+      data = data[kIndexEntrySize:]
+      next_id, next_offset = struct.unpack("<HI", data[:kIndexEntrySize])
+      resources[id] = original_data[offset:next_offset]
+
+    return DataPackContents(resources, encoding)
+
+  @staticmethod
+  def WriteDataPackToString(resources, encoding):
+    """Write a map of id=>data into a string in the data pack format and return
+    it."""
+    ids = sorted(resources.keys())
+    ret = []
+
+    # Write file header.
+    ret.append(struct.pack("<IIB", PACK_FILE_VERSION, len(ids), encoding))
+    HEADER_LENGTH = 2 * 4 + 1            # Two uint32s and one uint8.
+
+    # Each entry is a uint16 + a uint32s. We have one extra entry for the last
+    # item.
+    index_length = (len(ids) + 1) * (2 + 4)
+
+    # Write index.
+    data_offset = HEADER_LENGTH + index_length
+    for id in ids:
+      ret.append(struct.pack("<HI", id, data_offset))
+      data_offset += len(resources[id])
+
+    ret.append(struct.pack("<HI", 0, data_offset))
+
+    # Write data.
+    for id in ids:
+      ret.append(resources[id])
+    return ''.join(ret)
+
+  @staticmethod
+  def WriteDataPack(resources, output_file, encoding):
+    """Write a map of id=>data into output_file as a data pack."""
+    file = open(output_file, "wb")
+    content = DataPack.WriteDataPackToString(resources, encoding)
+    file.write(content)
+
+  @staticmethod
+  def RePack(output_file, input_files):
+    """Write a new data pack to |output_file| based on a list of filenames
+    (|input_files|)"""
+    resources = {}
+    encoding = None
+    for filename in input_files:
+      new_content = DataPack.ReadDataPack(filename)
+
+      # Make sure we have no dups.
+      duplicate_keys = set(new_content.resources.keys()) & set(resources.keys())
+      if len(duplicate_keys) != 0:
+        raise exceptions.KeyError("Duplicate keys: " +
+                                  str(list(duplicate_keys)))
+
+      # Make sure encoding is consistent.
+      if encoding in (None, BINARY):
+        encoding = new_content.encoding
+      elif new_content.encoding not in (BINARY, encoding):
+          raise exceptions.KeyError("Inconsistent encodings: " +
+                                    str(encoding) + " vs " +
+                                    str(new_content.encoding))
+
+      resources.update(new_content.resources)
+
+    # Encoding is 0 for BINARY, 1 for UTF8 and 2 for UTF16
+    if encoding is None:
+      encoding = BINARY
+    DataPack.WriteDataPack(resources, output_file, encoding)
+
+def main():
+  # Just write a simple file.
+  data = { 1: "", 4: "this is id 4", 6: "this is id 6", 10: "" }
+  DataPack.WriteDataPack(data, "datapack1.pak", UTF8)
+  data2 = { 1000: "test", 5: "five" }
+  DataPack.WriteDataPack(data2, "datapack2.pak", UTF8)
+  print "wrote datapack1 and datapack2 to current directory."
+
+if __name__ == '__main__':
+  main()