[Suggestions] Adding a Thumbnail Manager for the Suggestions Service

chrome/browser/search/suggestions/thumbnail_manager.cc

+// 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 "chrome/browser/search/suggestions/thumbnail_manager.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/search/suggestions/proto/suggestions.pb.h"
+#include "net/base/load_flags.h"
+
+namespace suggestions {
+
+ThumbnailManager::ThumbnailManager(Profile* profile)
+    : url_request_context_(profile->GetRequestContext()) {}
+
+ThumbnailManager::~ThumbnailManager() {}
+
+ThumbnailManager::Session::Session() {}

[huangs, 2014/05/22 18:08:22]

Can erase these, per. comment in .h file.

[Mathieu, 2014/05/22 19:46:32]

I don't think so :/

+
+ThumbnailManager::Session::~Session() {}
+
+void ThumbnailManager::InitializeThumbnailMap(
+    const SuggestionsProfile& suggestions) {
+  thumbnail_map_.clear();
+  for (int i = 0; i < suggestions.suggestions_size(); ++i) {
+    const ChromeSuggestion& suggestion = suggestions.suggestions(i);
+    if (suggestion.has_thumbnail()) {
+      thumbnail_map_[GURL(suggestion.url())] = GURL(suggestion.thumbnail());
+    }
+  }
+}
+
+void ThumbnailManager::GetPageThumbnail(const GURL& url,
+                                        BitmapResponseCallback callback) {

[huangs, 2014/05/22 18:08:22]

#include "content/public/browser/browser_thread.h"

...

  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[Mathieu, 2014/05/22 19:46:32]

Done.

+  // If the |url| is not in the |thumbnail_map_|, there is no associated

[huangs, 2014/05/22 18:08:22]

Perhaps:

// If |url| is not found in |thumbnail_map_|, then invoke |callback| with NULL
since there is no associated thumbnail.

[Mathieu, 2014/05/22 19:46:32]

Done.

+  // thumbnail for it. Will callback with an empty bitmap.
+  GURL thumbnail_url;
+  if (!GetThumbnailURL(url, &thumbnail_url)) {
+    callback.Run(url, NULL);
+    return;
+  }
+
+  // Get or create the ThumbnailManagerSession. In the case of a creation,

[huangs, 2014/05/22 18:08:22]

// Look for a fetch in progress for |thumbnail_url|.

[Mathieu, 2014/05/22 19:46:32]

Done.

+  // set the website URL.
+  ThumbnailSessionMap::iterator it = session_map_.find(thumbnail_url);
+  if (it == session_map_.end()) {
+    // There are no fetches in progress for |thumbnail_url|. Create a session

[huangs, 2014/05/22 18:08:22]

// |thumbnail_url| is not being fetched, so create a session and initiate the
fetch.

[Mathieu, 2014/05/22 19:46:32]

Done.

+    // and initiate the fetch.
+    Session* session = &session_map_[thumbnail_url];
+    session->url_ = url;
+    session->callbacks_.push(callback);
+    session->fetcher_ = new chrome::BitmapFetcher(thumbnail_url, this);

[huangs, 2014/05/22 18:08:22]

// This is deallocated in OnFetchComplete().

[Mathieu, 2014/05/22 19:46:32]

Done.

+    session->fetcher_->Start(
+        url_request_context_, std::string(),
+        net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE,
+        net::LOAD_NORMAL);
+  } else {
+    // Fetch in progress. Register as an interested callback.
+    it->second.callbacks_.push(callback);
+  }
+}
+
+void ThumbnailManager::OnFetchComplete(const GURL thumbnail_url,
+                                       const SkBitmap* bitmap) {
+  ThumbnailSessionMap::iterator it = session_map_.find(thumbnail_url);
+  DCHECK(it != session_map_.end());
+
+  Session* session = &it->second;
+
+  // Make sure the |fetcher| is deallocated.
+  scoped_ptr<chrome::BitmapFetcher> fetcher_destructor(session->fetcher_);
+
+  // Here |bitmap| could be NULL or a pointer to a bitmap which is owned by the
+  // BitmapFetcher and which ceases to exist after this function. Pass the
+  // un-owned pointer to the registered callbacks.
+  std::queue<BitmapResponseCallback> callbacks;
+  callbacks.swap(session->callbacks_);
+  while (!callbacks.empty()) {
+    callbacks.front().Run(session->url_, bitmap);
+    callbacks.pop();
+  }
+  session_map_.erase(it);
+}
+
+bool ThumbnailManager::GetThumbnailURL(const GURL& url, GURL* thumbnail_url) {
+  std::map<GURL, GURL>::iterator it = thumbnail_map_.find(url);
+  if (it == thumbnail_map_.end()) {
+    // Not found.

[huangs, 2014/05/22 18:08:22]

NIT: can be shortened to 2 liens:

if (it == thumbnail_map_.end())
  return false;  // Not found.

[Mathieu, 2014/05/22 19:46:32]

Done.

+    return false;
+  }
+  *thumbnail_url = it->second;
+  return true;
+}
+
+}  // namespace suggestions