Move TranslateURLFetcher to the translate component

This CL introduces the TranslateDelegate to inject the required
dependencies in the translate component.
TranslateDelegate is a singleton for now, but this will need to be
revisited once the ownership model of TranslateManager is improved.

BUG=331509

Review URL: https://codereview.chromium.org/131463002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244199 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 198 insertions, 0 deletions

diff --git a/components/translate.gypi b/components/translate.gypi
index 474b529..f07beae 100644
--- a/components/translate.gypi
+++ b/components/translate.gypi
@@ -20,9 +20,12 @@
         'translate/core/browser/page_translated_details.h',
         'translate/core/browser/translate_browser_metrics.cc',
         'translate/core/browser/translate_browser_metrics.h',
+        'translate/core/browser/translate_delegate.h',
         'translate/core/browser/translate_error_details.h',
         'translate/core/browser/translate_event_details.cc',
         'translate/core/browser/translate_event_details.h',
+        'translate/core/browser/translate_url_fetcher.cc',
+        'translate/core/browser/translate_url_fetcher.h',
        ],
     },
     {
diff --git a/components/translate/DEPS b/components/translate/DEPS
index c2106de..fe13494 100644
--- a/components/translate/DEPS
+++ b/components/translate/DEPS
@@ -1,5 +1,6 @@
 include_rules = [
   "+components/language_usage_metrics",
+  "+net",
 
   # Translate is a layered component; subdirectories must explicitly introduce
   # the ability to use the content layer as appropriate.
diff --git a/components/translate/core/browser/translate_delegate.h b/components/translate/core/browser/translate_delegate.h
new file mode 100644
index 0000000..2e5735c
--- /dev/null
+++ b/components/translate/core/browser/translate_delegate.h
@@ -0,0 +1,21 @@
+// Copyright 2014 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.
+
+#ifndef COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_DELEGATE_H_
+#define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_DELEGATE_H_
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+// A concrete instance of TranslateDelegate has to be provided by the embedder
+// of the Translate component.
+class TranslateDelegate {
+ public:
+  //Returns the URL request context in which the Translate component should make
+  //requests.
+  virtual net::URLRequestContextGetter* GetURLRequestContext() = 0;
+};
+
+#endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_DELEGATE_H_
diff --git a/components/translate/core/browser/translate_url_fetcher.cc b/components/translate/core/browser/translate_url_fetcher.cc
new file mode 100644
index 0000000..a029369
--- /dev/null
+++ b/components/translate/core/browser/translate_url_fetcher.cc
@@ -0,0 +1,83 @@
+// Copyright 2014 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 "components/translate/core/browser/translate_url_fetcher.h"
+
+#include "components/translate/core/browser/translate_delegate.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_request_status.h"
+
+namespace {
+
+// Retry parameter for fetching.
+const int kMaxRetry = 16;
+
+}  // namespace
+
+TranslateURLFetcher::TranslateURLFetcher(int id, TranslateDelegate* delegate)
+    : id_(id),
+      translate_delegate_(delegate),
+      state_(IDLE),
+      retry_count_(0) {
+}
+
+TranslateURLFetcher::~TranslateURLFetcher() {
+}
+
+bool TranslateURLFetcher::Request(
+    const GURL& url,
+    const TranslateURLFetcher::Callback& callback) {
+  // This function is not supposed to be called before previous operaion is not
+  // finished.
+  if (state_ == REQUESTING) {
+    NOTREACHED();
+    return false;
+  }
+
+  if (retry_count_ >= kMaxRetry)
+    return false;
+  retry_count_++;
+
+  state_ = REQUESTING;
+  url_ = url;
+  callback_ = callback;
+
+  fetcher_.reset(net::URLFetcher::Create(
+      id_,
+      url_,
+      net::URLFetcher::GET,
+      this));
+  fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
+                         net::LOAD_DO_NOT_SAVE_COOKIES);
+  fetcher_->SetRequestContext(translate_delegate_->GetURLRequestContext());
+  // Set retry parameter for HTTP status code 5xx. This doesn't work against
+  // 106 (net::ERR_INTERNET_DISCONNECTED) and so on.
+  // TranslateLanguageList handles network status, and implements retry.
+  fetcher_->SetMaxRetriesOn5xx(max_retry_on_5xx_);
+  if (!extra_request_header_.empty())
+    fetcher_->SetExtraRequestHeaders(extra_request_header_);
+
+  fetcher_->Start();
+
+  return true;
+}
+
+void TranslateURLFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK(fetcher_.get() == source);
+
+  std::string data;
+  if (source->GetStatus().status() == net::URLRequestStatus::SUCCESS &&
+      source->GetResponseCode() == net::HTTP_OK) {
+    state_ = COMPLETED;
+    source->GetResponseAsString(&data);
+  } else {
+    state_ = FAILED;
+  }
+
+  // Transfer URLFetcher's ownership before invoking a callback.
+  scoped_ptr<const net::URLFetcher> delete_ptr(fetcher_.release());
+  callback_.Run(id_, state_ == COMPLETED, data);
+}
diff --git a/components/translate/core/browser/translate_url_fetcher.h b/components/translate/core/browser/translate_url_fetcher.h
new file mode 100644
index 0000000..a702e33
--- /dev/null
+++ b/components/translate/core/browser/translate_url_fetcher.h
@@ -0,0 +1,90 @@
+// Copyright 2014 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.
+
+#ifndef COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_URL_FETCHER_H_
+#define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_URL_FETCHER_H_
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "url/gurl.h"
+
+class TranslateDelegate;
+
+class TranslateURLFetcher : public net::URLFetcherDelegate {
+ public:
+  // Callback type for Request().
+  typedef base::Callback<void(int, bool, const std::string&)> Callback;
+
+  // Represents internal state if the fetch is completed successfully.
+  enum State {
+    IDLE,        // No fetch request was issued.
+    REQUESTING,  // A fetch request was issued, but not finished yet.
+    COMPLETED,   // The last fetch request was finished successfully.
+    FAILED,      // The last fetch request was finished with a failure.
+  };
+
+  // |delegate| is expected to outlive the TranslateURLFetcher.
+  explicit TranslateURLFetcher(int id, TranslateDelegate* delegate);
+  virtual ~TranslateURLFetcher();
+
+  int max_retry_on_5xx() {
+    return max_retry_on_5xx_;
+  }
+  void set_max_retry_on_5xx(int count) {
+    max_retry_on_5xx_ = count;
+  }
+
+  const std::string& extra_request_header() {
+    return extra_request_header_;
+  }
+  void set_extra_request_header(const std::string& header) {
+    extra_request_header_ = header;
+  }
+
+  // Requests to |url|. |callback| will be invoked when the function returns
+  // true, and the request is finished asynchronously.
+  // Returns false if the previous request is not finished, or the request
+  // is omitted due to retry limitation.
+  bool Request(const GURL& url, const Callback& callback);
+
+  // Gets internal state.
+  State state() { return state_; }
+
+  // net::URLFetcherDelegate implementation:
+  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
+
+ private:
+  // URL to send the request.
+  GURL url_;
+
+  // ID which is assigned to the URLFetcher.
+  const int id_;
+
+  // Used to get information from the embedder of Translate.
+  TranslateDelegate* translate_delegate_;
+
+  // Internal state.
+  enum State state_;
+
+  // URLFetcher instance.
+  scoped_ptr<net::URLFetcher> fetcher_;
+
+  // Callback passed at Request(). It will be invoked when an asynchronous
+  // fetch operation is finished.
+  Callback callback_;
+
+  // Counts how many times did it try to fetch the language list.
+  int retry_count_;
+
+  // Max number how many times to retry on the server error
+  int max_retry_on_5xx_;
+
+  // An extra HTTP request header
+  std::string extra_request_header_;
+
+  DISALLOW_COPY_AND_ASSIGN(TranslateURLFetcher);
+};
+
+#endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_URL_FETCHER_H_