Translate: split supporting language list handling to TranslateLanguageList

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/command_line.h"
+#include "base/json/json_reader.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "base/values.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/translate/translate_url_util.h"
+#include "chrome/common/chrome_switches.h"
+#include "googleurl/src/gurl.h"
+#include "net/base/load_flags.h"
+#include "net/base/url_util.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_request_status.h"
+
+namespace {
+
+// The default list of languages the Google translation server supports.
+// We use this list until we receive the list that the server exposes.
+// For information, here is the list of languages that Chrome can be run in
+// but that the translation server does not support:
+// am Amharic
+// bn Bengali
+// gu Gujarati
+// kn Kannada
+// ml Malayalam
+// mr Marathi
+// ta Tamil
+// te Telugu
+const char* const kDefaultSupportedLanguages[] = {
+  "af",     // Afrikaans
+  "sq",     // Albanian
+  "ar",     // Arabic
+  "be",     // Belarusian
+  "bg",     // Bulgarian
+  "ca",     // Catalan
+  "zh-CN",  // Chinese (Simplified)
+  "zh-TW",  // Chinese (Traditional)
+  "hr",     // Croatian
+  "cs",     // Czech
+  "da",     // Danish
+  "nl",     // Dutch
+  "en",     // English
+  "eo",     // Esperanto
+  "et",     // Estonian
+  "tl",     // Filipino
+  "fi",     // Finnish
+  "fr",     // French
+  "gl",     // Galician
+  "de",     // German
+  "el",     // Greek
+  "ht",     // Haitian Creole
+  "iw",     // Hebrew
+  "hi",     // Hindi
+  "hu",     // Hungarian
+  "is",     // Icelandic
+  "id",     // Indonesian
+  "ga",     // Irish
+  "it",     // Italian
+  "ja",     // Japanese
+  "ko",     // Korean
+  "lv",     // Latvian
+  "lt",     // Lithuanian
+  "mk",     // Macedonian
+  "ms",     // Malay
+  "mt",     // Maltese
+  "no",     // Norwegian
+  "fa",     // Persian
+  "pl",     // Polish
+  "pt",     // Portuguese
+  "ro",     // Romanian
+  "ru",     // Russian
+  "sr",     // Serbian
+  "sk",     // Slovak
+  "sl",     // Slovenian
+  "es",     // Spanish
+  "sw",     // Swahili
+  "sv",     // Swedish
+  "th",     // Thai
+  "tr",     // Turkish
+  "uk",     // Ukrainian
+  "vi",     // Vietnamese
+  "cy",     // Welsh
+  "yi",     // Yiddish
+};
+
+// 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;
+
+}  // namespace
+
+// This must be kept in sync with the &cb= value in the kLanguageListFetchURL.
+const char TranslateLanguageList::kLanguageListCallbackName[] = "sl(";
+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]);
+}
+
+TranslateLanguageList::~TranslateLanguageList() {}
+
+void TranslateLanguageList::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK(url_fetcher_.get() == source);
+  scoped_ptr<const net::URLFetcher> delete_ptr(url_fetcher_.release());
+
+  if (source->GetStatus().status() == net::URLRequestStatus::SUCCESS &&
+      source->GetResponseCode() == net::HTTP_OK) {
+    std::string data;
+    source->GetResponseAsString(&data);
+    SetSupportedLanguages(data);
+  } else {
+    // TODO(toyoshim): Try again. http://crbug.com/244202 .
+    VLOG(9) << "Failed to Fetch languages from: " << kLanguageListFetchURL;
+  }
+}
+
+void TranslateLanguageList::GetSupportedLanguages(
+    std::vector<std::string>* languages) {
+  DCHECK(languages && languages->empty());
+  std::set<std::string>::const_iterator iter = supported_languages_.begin();
+  for (; iter != supported_languages_.end(); ++iter)
+    languages->push_back(*iter);
+}
+
+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& page_language) {
+  return supported_languages_.count(page_language) != 0;
+}
+
+void TranslateLanguageList::RequestLanguageList() {
+  if (url_fetcher_.get())
+    return;
+
+  GURL language_list_fetch_url = GURL(kLanguageListFetchURL);
+  language_list_fetch_url =
+      TranslateURLUtil::AddHostLocaleToUrl(language_list_fetch_url);
+  language_list_fetch_url =
+      TranslateURLUtil::AddApiKeyToUrl(language_list_fetch_url);
+
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(switches::kEnableTranslateAlphaLanguages)) {
+    language_list_fetch_url = net::AppendQueryParameter(
+        language_list_fetch_url,
+        kAlphaLanguageQueryName,
+        kAlphaLanguageQueryValue);
+  }
+
+  VLOG(9) << "Fetch supporting language list from: "
+          << language_list_fetch_url.spec().c_str();
+
+  url_fetcher_.reset(net::URLFetcher::Create(1,
+                                             language_list_fetch_url,
+                                             net::URLFetcher::GET,
+                                             this));
+  url_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
+                             net::LOAD_DO_NOT_SAVE_COOKIES);
+  url_fetcher_->SetRequestContext(g_browser_process->system_request_context());
+  url_fetcher_->SetMaxRetriesOn5xx(kMaxRetryLanguageListFetch);
+  url_fetcher_->Start();
+}
+
+void TranslateLanguageList::SetSupportedLanguages(
+    const std::string& language_list) {
+  // The format is:
+  // sl({"sl": {"XX": "LanguageName", ...}, "tl": {"XX": "LanguageName", ...}})
+  // Where "sl(" is set in kLanguageListCallbackName
+  // and "tl" is kTargetLanguagesKey
+  if (!StartsWithASCII(language_list,
+                       TranslateLanguageList::kLanguageListCallbackName,
+                       false) ||
+      !EndsWith(language_list, ")", false)) {
+    // We don't have a NOTREACHED here since this can happen in ui_tests, even
+    // though the the BrowserMain function won't call us with parameters.ui_task
+    // is NULL some tests don't set it, so we must bail here.
+    return;
+  }
+  static const size_t kLanguageListCallbackNameLength =
+      strlen(TranslateLanguageList::kLanguageListCallbackName);
+  std::string languages_json = language_list.substr(
+      kLanguageListCallbackNameLength,
+      language_list.size() - kLanguageListCallbackNameLength - 1);
+  scoped_ptr<Value> json_value(
+      base::JSONReader::Read(languages_json, base::JSON_ALLOW_TRAILING_COMMAS));
+  if (json_value == NULL || !json_value->IsType(Value::TYPE_DICTIONARY)) {
+    NOTREACHED();
+    return;
+  }
+  // The first level dictionary contains two sub-dict, one for source languages
+  // and the other for target languages, we want to use the target languages.
+  DictionaryValue* language_dict =
+      static_cast<DictionaryValue*>(json_value.get());
+  DictionaryValue* target_languages = NULL;
+  if (!language_dict->GetDictionary(TranslateLanguageList::kTargetLanguagesKey,
+                                    &target_languages) ||
+      target_languages == NULL) {
+    NOTREACHED();
+    return;
+  }
+  // Now we can clear our current state...
+  supported_languages_.clear();
+  // ... and replace it with the values we just fetched from the server.
+  for (DictionaryValue::Iterator iter(*target_languages);
+       !iter.IsAtEnd();
+       iter.Advance()) {
+    supported_languages_.insert(iter.key());
+  }
+}