# Copyright 2012 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
'''Fast and efficient parser for XTB files.
'''
import sys
import xml.sax
import xml.sax.handler
import grit.node.base
class XtbContentHandler(xml.sax.handler.ContentHandler):
'''A content handler that calls a given callback function for each
translation in the XTB file.
'''
def __init__(self, callback, defs=None, debug=False, target_platform=None):
self.callback = callback
self.debug = debug
# 0 if we are not currently parsing a translation, otherwise the message
# ID of that translation.
self.current_id = 0
# Empty if we are not currently parsing a translation, otherwise the
# parts we have for that translation - a list of tuples
# (is_placeholder, text)
self.current_structure = []
# Set to the language ID when we see the <translationbundle> node.
self.language = ''
# Keep track of the if block we're inside. We can't nest ifs.
self.if_expr = None
# Root defines to be used with if expr.
if defs:
self.defines = defs
else:
self.defines = {}
# Target platform for build.
if target_platform:
self.target_platform = target_platform
else:
self.target_platform = sys.platform
def startElement(self, name, attrs):
if name == 'translation':
assert self.current_id == 0 and len(self.current_structure) == 0, (
"Didn't expect a <translation> element here.")
self.current_id = attrs.getValue('id')
elif name == 'ph':
assert self.current_id != 0, "Didn't expect a <ph> element here."
self.current_structure.append((True, attrs.getValue('name')))
elif name == 'translationbundle':
self.language = attrs.getValue('lang')
elif name in ('if', 'then', 'else'):
assert self.if_expr is None, "Can't nest <if> or use <else> in xtb files"
self.if_expr = attrs.getValue('expr')
def endElement(self, name):
if name == 'translation':
assert self.current_id != 0
defs = self.defines
def pp_ifdef(define):
return define in defs
def pp_if(define):
return define in defs and defs[define]
# If we're in an if block, only call the callback (add the translation)
# if the expression is True.
should_run_callback = True
if self.if_expr:
should_run_callback = grit.node.base.Node.EvaluateExpression(
self.if_expr, self.defines, self.target_platform)
if should_run_callback:
self.callback(self.current_id, self.current_structure)
self.current_id = 0
self.current_structure = []
elif name == 'if':
assert self.if_expr is not None
self.if_expr = None
def characters(self, content):
if self.current_id != 0:
# We are inside a <translation> node so just add the characters to our
# structure.
#
# This naive way of handling characters is OK because in the XTB format,
# <ph> nodes are always empty (always <ph name="XXX"/>) and whitespace
# inside the <translation> node should be preserved.
self.current_structure.append((False, content))
class XtbErrorHandler(xml.sax.handler.ErrorHandler):
def error(self, exception):
pass
def fatalError(self, exception):
raise exception
def warning(self, exception):
pass
def Parse(xtb_file, callback_function, defs=None, debug=False,
target_platform=None):
'''Parse xtb_file, making a call to callback_function for every translation
in the XTB file.
The callback function must have the signature as described below. The 'parts'
parameter is a list of tuples (is_placeholder, text). The 'text' part is
either the raw text (if is_placeholder is False) or the name of the placeholder
(if is_placeholder is True).
Args:
xtb_file: open('fr.xtb', 'rb')
callback_function: def Callback(msg_id, parts): pass
defs: None, or a dictionary of preprocessor definitions.
debug: Default False. Set True for verbose debug output.
target_platform: None, or a sys.platform-like identifier of the build
target platform.
Return:
The language of the XTB, e.g. 'fr'
'''
# Start by advancing the file pointer past the DOCTYPE thing, as the TC
# uses a path to the DTD that only works in Unix.
# TODO(joi) Remove this ugly hack by getting the TC gang to change the
# XTB files somehow?
front_of_file = xtb_file.read(1024)
xtb_file.seek(front_of_file.find(b'<translationbundle'))
handler = XtbContentHandler(callback=callback_function, defs=defs,
debug=debug, target_platform=target_platform)
xml.sax.parse(xtb_file, handler)
assert handler.language != ''
return handler.language
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