Bring up of ImageService.

components/enhanced_bookmarks/bookmark_image_service.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 "components/enhanced_bookmarks/bookmark_image_service.h"
+
+#include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "components/bookmarks/browser/bookmark_model.h"
+#include "components/bookmarks/browser/bookmark_model_observer.h"
+#include "components/enhanced_bookmarks/enhanced_bookmark_utils.h"
+#include "components/enhanced_bookmarks/metadata_accessor.h"
+#include "components/enhanced_bookmarks/persistent_image_store.h"
+
+namespace {
+
+const char kSequenceToken[] = "BookmarkImagesSequenceToken";
+
+void ConstructPersistentImageStore(PersistentImageStore* store,
+                                   const base::FilePath& path) {
+  DCHECK(store);
+  new (store) PersistentImageStore(path);
+}
+
+void DeleteImageStore(ImageStore* store) {
+  DCHECK(store);
+  delete store;
+}
+
+void RetrieveImageFromStoreRelay(
+    ImageStore* store,
+    const GURL& page_url,
+    enhanced_bookmarks::BookmarkImageService::Callback callback,
+    scoped_refptr<base::SingleThreadTaskRunner> origin_loop) {
+  std::pair<gfx::Image, GURL> image_data = store->Get(page_url);
+  origin_loop->PostTask(
+      FROM_HERE, base::Bind(callback, image_data.first, image_data.second));
+}
+
+}  // namespace
+
+namespace enhanced_bookmarks {
+BookmarkImageService::BookmarkImageService(
+    scoped_ptr<ImageStore> store,
+    BookmarkModel* bookmark_model,
+    scoped_refptr<base::SequencedWorkerPool> pool)
+    : bookmark_model_(bookmark_model), store_(store.Pass()), pool_(pool) {
+  DCHECK(CalledOnValidThread());
+  bookmark_model_->AddObserver(this);
+}
+
+BookmarkImageService::BookmarkImageService(
+    const base::FilePath& path,
+    BookmarkModel* bookmark_model,
+    scoped_refptr<base::SequencedWorkerPool> pool)
+    : bookmark_model_(bookmark_model), pool_(pool) {
+  DCHECK(CalledOnValidThread());
+  // PersistentImageStore has to be constructed in the thread it will be used,
+  // so we are posting the construction to the thread.  However, we first
+  // allocate memory and keep here. The reason is that, before
+  // PersistentImageStore construction is done, it's possible that
+  // another member function, that posts store_ to the thread, is called.
+  // Although the construction might not be finished yet, we still want to post
+  // the task since it's guaranteed to be constructed by the time it is used, by
+  // the sequential thread task pool.
+  //
+  // Other alternatives:
+  // - Using a lock or WaitableEvent for PersistentImageStore construction.
+  //   But waiting on UI thread is discouraged.
+  // - Posting the current BookmarkImageService instance instead of store_.
+  //   But this will require using a weak pointer and can potentially block
+  //   destroying BookmarkImageService.
+  PersistentImageStore* store =
+      (PersistentImageStore*)::operator new(sizeof(PersistentImageStore));
+  store_.reset(store);
+  pool_->PostNamedSequencedWorkerTask(
+      kSequenceToken,
+      FROM_HERE,
+      base::Bind(&ConstructPersistentImageStore, store, path));
+}
+
+BookmarkImageService::~BookmarkImageService() {
+  DCHECK(CalledOnValidThread());
+  bookmark_model_->RemoveObserver(this);
+  pool_->PostNamedSequencedWorkerTask(
+      kSequenceToken,
+      FROM_HERE,
+      base::Bind(&DeleteImageStore, store_.release()));
+}
+
+void BookmarkImageService::SalientImageForUrl(const GURL& page_url,
+                                              Callback callback) {
+  DCHECK(CalledOnValidThread());
+  SalientImageForUrl(page_url, true, callback);
+}
+
+void BookmarkImageService::RetrieveImageFromStore(
+    const GURL& page_url,
+    BookmarkImageService::Callback callback) {
+  DCHECK(CalledOnValidThread());
+  pool_->PostSequencedWorkerTaskWithShutdownBehavior(
+      pool_->GetNamedSequenceToken(kSequenceToken),
+      FROM_HERE,
+      base::Bind(&RetrieveImageFromStoreRelay,
+                 base::Unretained(store_.get()),
+                 page_url,
+                 callback,
+                 base::ThreadTaskRunnerHandle::Get()),
+      base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+}
+
+void BookmarkImageService::RetrieveSalientImageForPageUrl(
+    const GURL& page_url) {
+  DCHECK(CalledOnValidThread());
+  if (IsPageUrlInProgress(page_url))
+    return;  // A request for this URL is already in progress.
+
+  in_progress_page_urls_.insert(page_url);
+
+  const BookmarkNode* bookmark =
+      bookmark_model_->GetMostRecentlyAddedUserNodeForURL(page_url);
+  GURL image_url;
+  if (bookmark) {
+    int width;
+    int height;
+    enhanced_bookmarks::ThumbnailImageFromBookmark(
+        bookmark, &image_url, &width, &height);
+  }
+
+  RetrieveSalientImage(
+      page_url,
+      image_url,
+      "",
+      net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE,

[wtc, 2014/08/28 23:45:50]

If we're passing a hardcoded value here, does RetrieveSalientImage really need
the 'referrer_policy' parameter?

[noyau (Ping after 24h), 2014/08/29 08:44:01]

RetrieveSalientImage() is protected and also called by the iOS specific subclass
(not yet in Chromium, the web layer has to land first) with the proper referrer
policy. RetrieveSalientImageForPageUrl() is called when the URL for the image
has been gatherer via sync, so the request is out of the blue, so this default
referrer policy is the proper one. The other way to get a URL is to extract it
from the page you just bookmarked or visited. As  there is no access to WebKit
in iOS the only way to retrieve the image then is to do a request, which is done
with RetrieveSalientImage() and in that case the referrer information is derived
from the page itself.

+      false);
+}
+
+void BookmarkImageService::FetchCallback(const GURL& page_url,
+                                         Callback original_callback,
+                                         const gfx::Image& image,
+                                         const GURL& image_url) {
+  DCHECK(CalledOnValidThread());
+  if (!image.IsEmpty() || !image_url.is_empty()) {
+    // Either the image was in the store or there is no image in the store, but
+    // an URL for an image is present, indicating that a previous attempt to
+    // download the image failed. Just return the image.
+    original_callback.Run(image, image_url);
+  } else {
+    // There is no image in the store, and no previous attempts to retrieve
+    // one. Start a request to retrieve a salient image if there is an image
+    // url set on a bookmark, and then enqueue the request for the image to
+    // be triggered when the retrieval is finished.
+    RetrieveSalientImageForPageUrl(page_url);
+    SalientImageForUrl(page_url, false, original_callback);
+  }
+}
+
+void BookmarkImageService::SalientImageForUrl(const GURL& page_url,
+                                              bool fetch_from_bookmark,
+                                              Callback callback) {
+  DCHECK(CalledOnValidThread());
+
+  // If the request is done while the image is currently being retrieved, just
+  // store the appropriate callbacks to call once the image is retrieved.
+  if (IsPageUrlInProgress(page_url)) {
+    callbacks_[page_url].push_back(callback);
+    return;
+  }
+
+  if (!fetch_from_bookmark) {
+    RetrieveImageFromStore(page_url, callback);
+  } else {
+    RetrieveImageFromStore(page_url,
+                           base::Bind(&BookmarkImageService::FetchCallback,
+                                      base::Unretained(this),
+                                      page_url,
+                                      callback));
+  }
+}
+
+void BookmarkImageService::ProcessNewImage(const GURL& page_url,
+                                           bool update_bookmarks,
+                                           const gfx::Image& image,
+                                           const GURL& image_url) {
+  DCHECK(CalledOnValidThread());
+  StoreImage(image, image_url, page_url);
+  in_progress_page_urls_.erase(page_url);
+  ProcessRequests(page_url, image, image_url);
+  if (update_bookmarks && image_url.is_valid()) {
+    const BookmarkNode* bookmark =
+        bookmark_model_->GetMostRecentlyAddedUserNodeForURL(page_url);
+    if (bookmark) {
+      const gfx::Size& size = image.Size();
+      bool result = enhanced_bookmarks::SetOriginalImageForBookmark(
+          bookmark_model_, bookmark, image_url, size.width(), size.height());
+      DCHECK(result);
+    }
+  }
+}
+
+bool BookmarkImageService::IsPageUrlInProgress(const GURL& page_url) {
+  DCHECK(CalledOnValidThread());
+  return in_progress_page_urls_.find(page_url) != in_progress_page_urls_.end();
+}
+
+void BookmarkImageService::StoreImage(const gfx::Image& image,
+                                      const GURL& image_url,
+                                      const GURL& page_url) {
+  DCHECK(CalledOnValidThread());
+  if (!image.IsEmpty()) {
+    pool_->PostNamedSequencedWorkerTask(
+        kSequenceToken,
+        FROM_HERE,
+        base::Bind(&ImageStore::Insert,
+                   base::Unretained(store_.get()),
+                   page_url,
+                   image_url,
+                   image));
+  }
+}
+
+void BookmarkImageService::RemoveImageForUrl(const GURL& page_url) {
+  DCHECK(CalledOnValidThread());
+  pool_->PostNamedSequencedWorkerTask(
+      kSequenceToken,
+      FROM_HERE,
+      base::Bind(&ImageStore::Erase, base::Unretained(store_.get()), page_url));
+  in_progress_page_urls_.erase(page_url);
+  ProcessRequests(page_url, gfx::Image(), GURL());
+}
+
+void BookmarkImageService::ChangeImageURL(const GURL& from, const GURL& to) {
+  DCHECK(CalledOnValidThread());
+  pool_->PostNamedSequencedWorkerTask(kSequenceToken,
+                                      FROM_HERE,
+                                      base::Bind(&ImageStore::ChangeImageURL,
+                                                 base::Unretained(store_.get()),
+                                                 from,
+                                                 to));
+  in_progress_page_urls_.erase(from);
+  ProcessRequests(from, gfx::Image(), GURL());
+}
+
+void BookmarkImageService::ClearAll() {
+  DCHECK(CalledOnValidThread());
+  // Clears and executes callbacks.
+  pool_->PostNamedSequencedWorkerTask(
+      kSequenceToken,
+      FROM_HERE,
+      base::Bind(&ImageStore::ClearAll, base::Unretained(store_.get())));
+
+  for (std::map<const GURL, std::vector<Callback> >::const_iterator it =
+           callbacks_.begin();
+       it != callbacks_.end();
+       ++it) {
+    ProcessRequests(it->first, gfx::Image(), GURL());
+  }
+
+  in_progress_page_urls_.erase(in_progress_page_urls_.begin(),
+                               in_progress_page_urls_.end());
+}
+
+void BookmarkImageService::ProcessRequests(const GURL& page_url,
+                                           const gfx::Image& image,
+                                           const GURL& image_url) {
+  DCHECK(CalledOnValidThread());
+
+  std::vector<Callback> callbacks = callbacks_[page_url];
+  for (std::vector<Callback>::const_iterator it = callbacks.begin();
+       it != callbacks.end();
+       ++it) {
+    it->Run(image, image_url);
+  }
+
+  callbacks_.erase(page_url);
+}
+
+// BookmarkModelObserver methods.
+
+void BookmarkImageService::BookmarkNodeRemoved(
+    BookmarkModel* model,
+    const BookmarkNode* parent,
+    int old_index,
+    const BookmarkNode* node,
+    const std::set<GURL>& removed_urls) {
+  DCHECK(CalledOnValidThread());
+  for (std::set<GURL>::const_iterator iter = removed_urls.begin();
+       iter != removed_urls.end();
+       ++iter) {
+    RemoveImageForUrl(*iter);
+  }
+}
+
+void BookmarkImageService::BookmarkModelLoaded(BookmarkModel* model,
+                                               bool ids_reassigned) {
+}
+
+void BookmarkImageService::BookmarkNodeMoved(BookmarkModel* model,
+                                             const BookmarkNode* old_parent,
+                                             int old_index,
+                                             const BookmarkNode* new_parent,
+                                             int new_index) {
+}
+
+void BookmarkImageService::BookmarkNodeAdded(BookmarkModel* model,
+                                             const BookmarkNode* parent,
+                                             int index) {
+}
+
+void BookmarkImageService::OnWillChangeBookmarkNode(BookmarkModel* model,
+                                                    const BookmarkNode* node) {
+  DCHECK(CalledOnValidThread());
+  if (node->is_url())
+    previous_url_ = node->url();
+}
+
+void BookmarkImageService::BookmarkNodeChanged(BookmarkModel* model,
+                                               const BookmarkNode* node) {
+  DCHECK(CalledOnValidThread());
+  if (node->is_url() && previous_url_ != node->url())
+    ChangeImageURL(previous_url_, node->url());
+}
+
+void BookmarkImageService::BookmarkNodeFaviconChanged(
+    BookmarkModel* model,
+    const BookmarkNode* node) {
+}
+
+void BookmarkImageService::BookmarkNodeChildrenReordered(
+    BookmarkModel* model,
+    const BookmarkNode* node) {
+}
+
+void BookmarkImageService::BookmarkAllUserNodesRemoved(
+    BookmarkModel* model,
+    const std::set<GURL>& removed_urls) {
+  ClearAll();
+}
+
+}  // namespace enhanced_bookmarks