[rac] Use stale libaddressinput data if download fails

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

Index: third_party/libaddressinput/chromium/cpp/src/retriever.cc
diff --git a/third_party/libaddressinput/chromium/cpp/src/retriever.cc b/third_party/libaddressinput/chromium/cpp/src/retriever.cc
index eebba3eb2d78b9b5d590f6aa8a4ba2819d39d7c1..e4b3c2c6e6ece050f9569436962266c4e22ef1ef 100644
--- a/third_party/libaddressinput/chromium/cpp/src/retriever.cc
+++ b/third_party/libaddressinput/chromium/cpp/src/retriever.cc
@@ -28,16 +28,30 @@
 
 #include "fallback_data_store.h"
 #include "util/stl_util.h"
+#include "wrapper.h"
 
 namespace i18n {
 namespace addressinput {
 
+namespace {
+
+// The number of seconds after which data is considered stale. The staleness
+// threshold is 30 days:
+//    30 days *
+//    24 hours per day *
+//    60 minutes per hour *
+//    60 seconds per minute.
+static const double kStaleDataAgeInSeconds = 30.0 * 24.0 * 60.0 * 60.0;
+
+}  // namespace
+
 Retriever::Retriever(const std::string& validation_data_url,
                      scoped_ptr<Downloader> downloader,
                      scoped_ptr<Storage> storage)
     : validation_data_url_(validation_data_url),
       downloader_(downloader.Pass()),
-      storage_(storage.Pass()) {
+      storage_(storage.Pass()),
+      stale_data_() {
   assert(validation_data_url_.length() > 0);
   assert(validation_data_url_[validation_data_url_.length() - 1] == '/');
   assert(storage_ != NULL);
@@ -66,14 +80,18 @@ void Retriever::Retrieve(const std::string& key,
 void Retriever::OnDataRetrievedFromStorage(bool success,
                                            const std::string& key,
                                            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) {
+  std::string unwrapped = stored_data;
+  double age_in_seconds = 0.0;
+  bool valid_format = Wrapper::Unwrap(&unwrapped, &age_in_seconds);
+  if (success && valid_format && age_in_seconds < kStaleDataAgeInSeconds) {
     scoped_ptr<Callback> retrieved = GetCallbackForKey(key);
     if (retrieved != NULL) {
-      (*retrieved)(success, key, stored_data);
+      (*retrieved)(success, key, unwrapped);
     }
   } else {
+    if (success && valid_format) {
+      stale_data_[key] = unwrapped;
+    }
     downloader_->Download(GetUrlForKey(key),
                           BuildCallback(this, &Retriever::OnDownloaded));
   }
@@ -84,13 +102,23 @@ void Retriever::OnDownloaded(bool success,
                              const std::string& downloaded_data) {
   const std::string& key = GetKeyForUrl(url);
   std::string response;
+  std::map<std::string, std::string>::iterator stale_data_it =
+      stale_data_.find(key);
+
   if (success) {
-    storage_->Put(key, downloaded_data);
+    storage_->Put(key, Wrapper::Wrap(downloaded_data));
     response = downloaded_data;
+  } else if (stale_data_it != stale_data_.end()) {
+    success = true;
+    response = stale_data_it->second;
   } else {
     success = FallbackDataStore::Get(key, &response);
   }
 
+  if (stale_data_it != stale_data_.end()) {
+    stale_data_.erase(stale_data_it);
+  }
+
   scoped_ptr<Callback> retrieved = GetCallbackForKey(key);
   if (retrieved != NULL) {
     (*retrieved)(success, key, response);