Translate: language list smart updater

chrome/browser/translate/translate_language_list.cc

 // Copyright 2013 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 "chrome/browser/translate/translate_language_list.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
@@ skipping 85 matching lines @@
 
 // Constant URL string to fetch server supporting language list.
 const char kLanguageListFetchURL[] =
     "https://translate.googleapis.com/translate_a/l?client=chrome&cb=sl";
 
 // Used in kTranslateScriptURL to request supporting languages list including
 // "alpha languages".
 const char kAlphaLanguageQueryName[] = "alpha";
 const char kAlphaLanguageQueryValue[] = "1";
 
-// Retry parameter for fetching supporting language list.
-const int kMaxRetryLanguageListFetch = 5;
-
 // Assign following IDs to URLFetchers so that tests can distinguish each
 // request in order to simiulate respectively.
 const int kFetcherIdForLanguageList = 1;
 const int kFetcherIdForAlphaLanguageList = 2;
 
+// Represent if the language list updater is disabled.
+bool update_is_disabled = false;
+
 // Show a message in chrome:://translate-internals Event Logs.
 void NotifyEvent(int line, const std::string& message) {
   TranslateManager* manager = TranslateManager::GetInstance();
   DCHECK(manager);
 
   TranslateEventDetails details(__FILE__, line, message);
   manager->NotifyTranslateEvent(details);
 }
 
 // Parses |language_list| containing the list of languages that the translate
@@ skipping 82 matching lines @@
 const char TranslateLanguageList::kTargetLanguagesKey[] = "tl";
 
 TranslateLanguageList::TranslateLanguageList() {
   // We default to our hard coded list of languages in
   // |kDefaultSupportedLanguages|. This list will be overriden by a server
   // providing supported langauges list.
   for (size_t i = 0; i < arraysize(kDefaultSupportedLanguages); ++i)
     supported_languages_.insert(kDefaultSupportedLanguages[i]);
   UpdateSupportedLanguages();
 
+  if (update_is_disabled)
+    return;
+
   language_list_fetcher_.reset(
       new TranslateURLFetcher(kFetcherIdForLanguageList));
   alpha_language_list_fetcher_.reset(
       new TranslateURLFetcher(kFetcherIdForAlphaLanguageList));
 }
 
 TranslateLanguageList::~TranslateLanguageList() {
 }
 
 void TranslateLanguageList::GetSupportedLanguages(
     std::vector<std::string>* languages) {
   DCHECK(languages && languages->empty());
   std::set<std::string>::const_iterator iter = all_supported_languages_.begin();
   for (; iter != all_supported_languages_.end(); ++iter)
     languages->push_back(*iter);
+
+  // Update language lists if they are not updated after Chrome was launched
+  // for later requests.
+  if (language_list_fetcher_.get() || alpha_language_list_fetcher_.get())
+    RequestLanguageList();
 }
 
 std::string TranslateLanguageList::GetLanguageCode(
     const std::string& chrome_locale) {
   // Only remove the country code for country specific languages we don't
   // support specifically yet.
   if (IsSupportedLanguage(chrome_locale))
     return chrome_locale;
 
   size_t hypen_index = chrome_locale.find('-');
   if (hypen_index == std::string::npos)
     return chrome_locale;
   return chrome_locale.substr(0, hypen_index);
 }
 
 bool TranslateLanguageList::IsSupportedLanguage(const std::string& language) {
   return all_supported_languages_.count(language) != 0;
 }
 
 bool TranslateLanguageList::IsAlphaLanguage(const std::string& language) {
   // |language| should exist only in the alpha language list.
   return supported_alpha_languages_.count(language) != 0 &&
          supported_languages_.count(language) == 0;
 }
 
 void TranslateLanguageList::RequestLanguageList() {
+  // If resource requests are not allowed, we'll get a callback when they are.
+  if (resource_request_allowed_notifier_.ResourceRequestsAllowed())
+    OnResourceRequestsAllowed();
+}
+
+void TranslateLanguageList::OnResourceRequestsAllowed() {
   if (language_list_fetcher_.get() &&
       (language_list_fetcher_->state() == TranslateURLFetcher::IDLE ||
        language_list_fetcher_->state() == TranslateURLFetcher::FAILED)) {
     GURL url = GetLanguageListFetchURL(false);
 
     std::string message = base::StringPrintf(
         "Language list fetch starts (URL: %s)",
         url.spec().c_str());
     NotifyEvent(__LINE__, message);
 
-    language_list_fetcher_->Request(
+    bool result = language_list_fetcher_->Request(
         url,
         base::Bind(&TranslateLanguageList::OnLanguageListFetchComplete,
                    base::Unretained(this)));
+    if (!result)
+      NotifyEvent(__LINE__, "Request is omitted due to retry limit");
   }
 
   if (alpha_language_list_fetcher_.get() &&
       (alpha_language_list_fetcher_->state() == TranslateURLFetcher::IDLE ||
        alpha_language_list_fetcher_->state() == TranslateURLFetcher::FAILED)) {
     GURL url = GetLanguageListFetchURL(true);
 
     std::string message = base::StringPrintf(
         "Alpha language list fetch starts (URL: %s)",
         url.spec().c_str());
     NotifyEvent(__LINE__, message);
 
-    alpha_language_list_fetcher_->Request(
+    bool result = alpha_language_list_fetcher_->Request(
         url,
         base::Bind(&TranslateLanguageList::OnLanguageListFetchComplete,
                    base::Unretained(this)));
+    if (!result)
+      NotifyEvent(__LINE__, "Request is omitted due to retry limit");
   }
 }
 
+// static
+void TranslateLanguageList::DisableUpdate() {
+  update_is_disabled = true;
+}
+
 void TranslateLanguageList::OnLanguageListFetchComplete(
     int id,
     bool success,
     const std::string& data) {
   if (!success) {
+    // Since it fails just now, omit to schedule resource requests if
+    // ResourceRequestAllowedNotifier think it's ready. Otherwise, a callback
+    // will be invoked later to request resources again.
+    // The TranslateURLFetcher has a limit for retried requests and aborts
+    // re-try not to invoke OnLanguageListFetchComplete anymore if it's asked to
+    // re-try too many times.
     GURL url = GetLanguageListFetchURL(id == kFetcherIdForAlphaLanguageList);
     std::string message = base::StringPrintf(
         "Failed to Fetch languages from: %s", url.spec().c_str());
     NotifyEvent(__LINE__, message);
     return;
   }
 
   std::string message = base::StringPrintf(
       "%s list is updated",
       id == kFetcherIdForLanguageList ? "Language" : "Alpha language");
@@ skipping 24 matching lines @@
        iter != supported_languages_.end();
        ++iter) {
     all_supported_languages_.insert(*iter);
   }
   for (iter = supported_alpha_languages_.begin();
        iter != supported_alpha_languages_.end();
        ++iter) {
     all_supported_languages_.insert(*iter);
   }
 }