libaddressinput: Add fallback data for US address validation.

third_party/libaddressinput/chromium/cpp/src/retriever.cc

 // Copyright (C) 2013 Google Inc.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #include "retriever.h"
 
 #include <libaddressinput/callback.h>
 #include <libaddressinput/downloader.h>
 #include <libaddressinput/storage.h>
 #include <libaddressinput/util/basictypes.h>
 #include <libaddressinput/util/scoped_ptr.h>
 
 #include <cassert>
 #include <cstddef>
 #include <map>
 #include <string>
 #include <utility>
 
+#include "fallback_data_store.h"
 #include "lookup_key_util.h"
 #include "util/stl_util.h"
 
 namespace i18n {
 namespace addressinput {
 
 Retriever::Retriever(const std::string& validation_data_url,
                      scoped_ptr<Downloader> downloader,
                      scoped_ptr<Storage> storage)
     : lookup_key_util_(validation_data_url),
@@ skipping 17 matching lines @@
     requests_.erase(request_it);
   }
 
   requests_[key] = retrieved.release();
   storage_->Get(key,
                 BuildCallback(this, &Retriever::OnDataRetrievedFromStorage));
 }
 
 void Retriever::OnDataRetrievedFromStorage(bool success,
                                            const std::string& key,
-                                           const std::string& data) {
+                                           const std::string& stored_data) {
   // TODO(rouslan): Add validation for data integrity and freshness. If a
   // download fails, then it's OK to use stale data.
   if (success) {
     scoped_ptr<Callback> retrieved = GetCallbackForKey(key);
     if (retrieved != NULL) {
-      (*retrieved)(success, key, data);
+      (*retrieved)(success, key, stored_data);
     }
   } else {
     downloader_->Download(lookup_key_util_.GetUrlForKey(key),
                           BuildCallback(this, &Retriever::OnDownloaded));
   }
 }
 
 void Retriever::OnDownloaded(bool success,
                              const std::string& url,
-                             const std::string& data) {
+                             const std::string& downloaded_data) {
+  std::string response;
   const std::string& key = lookup_key_util_.GetKeyForUrl(url);
   if (success) {
-    storage_->Put(key, data);
+    storage_->Put(key, downloaded_data);
+    response = downloaded_data;
+  } else {
+    success = FallbackDataStore::Get(key, &response);
   }
+
   scoped_ptr<Callback> retrieved = GetCallbackForKey(key);
   if (retrieved != NULL) {
-    (*retrieved)(success, key, success ? data : std::string());
+    (*retrieved)(success, key, response);
   }
 }
 
 scoped_ptr<Retriever::Callback> Retriever::GetCallbackForKey(
     const std::string& key) {
   std::map<std::string, Callback*>::iterator iter =
       requests_.find(key);
   if (iter == requests_.end()) {
     // An abandonened request.
     return scoped_ptr<Callback>();
   }
   scoped_ptr<Callback> callback(iter->second);
   requests_.erase(iter);
   return callback.Pass();
 }
 
 }  // namespace addressinput
 }  // namespace i18n