[MD settings] i18n source stream filtering

content/browser/webui/web_ui_data_source_impl.cc

 // 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.
 
 #include "content/browser/webui/web_ui_data_source_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
@@ skipping 194 matching lines @@
 }
 
 void WebUIDataSourceImpl::DisableDenyXFrameOptions() {
   deny_xframe_options_ = false;
 }
 
 void WebUIDataSourceImpl::DisableI18nAndUseGzipForAllPaths() {
   use_gzip_for_all_paths_ = true;
 }
 
+void WebUIDataSourceImpl::FinalizeReplacements() {

[Dan Beam, 2016/12/03 02:25:28]

nit: EnsureLoadTimeDataDefaultsAdded() ?

[dschuyler, 2016/12/03 02:44:57]

Done.

+  // After this function is called, make no further changes to |replacements_|.
+  if (!add_load_time_data_defaults_)
+    return;
+
+  add_load_time_data_defaults_ = false;
+  std::string locale = GetContentClient()->browser()->GetApplicationLocale();
+  base::DictionaryValue defaults;
+  webui::SetLoadTimeDataDefaults(locale, &defaults);
+  AddLocalizedStrings(defaults);
+}
+
+const ui::TemplateReplacements* WebUIDataSourceImpl::GetReplacements() const {
+  return &replacements_;
+}
+
 std::string WebUIDataSourceImpl::GetSource() const {
   return source_name_;
 }
 
 std::string WebUIDataSourceImpl::GetMimeType(const std::string& path) const {
   // Remove the query string for to determine the mime type.
   std::string file_path = path.substr(0, path.find_first_of('?'));
 
   if (base::EndsWith(file_path, ".css", base::CompareCase::INSENSITIVE_ASCII))
     return "text/css";
@@ skipping 15 matching lines @@
 
 void WebUIDataSourceImpl::StartDataRequest(
     const std::string& path,
     const ResourceRequestInfo::WebContentsGetter& wc_getter,
     const URLDataSource::GotDataCallback& callback) {
   if (!filter_callback_.is_null() &&
       filter_callback_.Run(path, callback)) {
     return;
   }
 
-  if (add_load_time_data_defaults_) {
-    std::string locale = GetContentClient()->browser()->GetApplicationLocale();
-    base::DictionaryValue defaults;
-    webui::SetLoadTimeDataDefaults(locale, &defaults);
-    AddLocalizedStrings(defaults);
-    add_load_time_data_defaults_ = false;
-  }
+  // The replacements are initiallized in the main thread and then used in the
+  // IO thread. The map is safe to read from multiple threads as long as no
+  // futher changes are made to it.
+  FinalizeReplacements();
 
   if (!json_path_.empty() && path == json_path_) {
     SendLocalizedStringsAsJSON(callback);
     return;
   }
 
   int resource_id = default_resource_;
   std::map<std::string, int>::iterator result;
   // Remove the query string for named resource lookups.
   std::string file_path = path.substr(0, path.find_first_of('?'));
   result = path_to_idr_map_.find(file_path);
   if (result != path_to_idr_map_.end())
     resource_id = result->second;
   DCHECK_NE(resource_id, -1);
   scoped_refptr<base::RefCountedMemory> response(
       GetContentClient()->GetDataResourceBytes(resource_id));
-
-  // TODO(dschuyler): improve filtering of which resource to run template
-  // expansion upon. TODO(dbeam): make a streaming filter that works on gzipped
-  // content.
-  if (response.get() && GetMimeType(path) == "text/html" &&
-      !source()->IsGzipped(path)) {
-    std::string replaced = ui::ReplaceTemplateExpressions(
-        base::StringPiece(response->front_as<char>(), response->size()),
-        replacements_);
-    response = base::RefCountedString::TakeString(&replaced);
-  }
-
   callback.Run(response.get());
 }
 
 void WebUIDataSourceImpl::SendLocalizedStringsAsJSON(
     const URLDataSource::GotDataCallback& callback) {
   std::string template_data;
   webui::AppendJsonJS(&localized_strings_, &template_data);
   callback.Run(base::RefCountedString::TakeString(&template_data));
 }
 
 }  // namespace content