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// 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 CHROME_BROWSER_BITMAP_FETCHER_BITMAP_FETCHER_SERVICE_H_
#define CHROME_BROWSER_BITMAP_FETCHER_BITMAP_FETCHER_SERVICE_H_
#include "base/compiler_specific.h"
#include "base/containers/mru_cache.h"
#include "base/containers/scoped_ptr_hash_map.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/scoped_vector.h"
#include "chrome/browser/bitmap_fetcher/bitmap_fetcher_delegate.h"
#include "components/keyed_service/core/keyed_service.h"
namespace content {
class BrowserContext;
} // namespace content
namespace chrome {
class BitmapFetcher;
} // namespace chrome
class BitmapFetcherRequest;
class GURL;
class SkBitmap;
// Service to retrieve images for Answers in Suggest.
class BitmapFetcherService : public KeyedService,
public chrome::BitmapFetcherDelegate {
public:
typedef int RequestId;
static const RequestId REQUEST_ID_INVALID = 0;
class Observer {
public:
virtual ~Observer() {}
// Called whenever the image changes. Called with an empty image if the
// fetch failed or the request ended for any reason.
// TODO(dschuyler) The comment differs from what the code does, follow-up.
virtual void OnImageChanged(RequestId request_id,
const SkBitmap& answers_image) = 0;
};
explicit BitmapFetcherService(content::BrowserContext* context);
~BitmapFetcherService() override;
// Cancels a request, if it is still in-flight.
void CancelRequest(RequestId requestId);
// Requests a new image. Will either trigger download or satisfy from cache.
// Takes ownership of |observer|. If there are too many outstanding requests,
// the request will fail and |observer| will be called to signal failure.
// Otherwise, |observer| will be called with either the cached image or the
// downloaded one.
// NOTE: The observer might be called back synchronously from RequestImage if
// the image is already in the cache.
RequestId RequestImage(const GURL& url, Observer* observer);
// Start fetching the image at the given |url|.
void Prefetch(const GURL& url);
protected:
// Create a bitmap fetcher for the given |url| and start it. Virtual method
// so tests can override this for different behavior.
virtual chrome::BitmapFetcher* CreateFetcher(const GURL& url);
private:
friend class BitmapFetcherServiceTest;
typedef ScopedVector<chrome::BitmapFetcher> BitmapFetchers;
// Gets the existing fetcher for |url| or constructs a new one if it doesn't
// exist.
const chrome::BitmapFetcher* EnsureFetcherForUrl(const GURL& url);
// Find a fetcher with a given |url|. Return NULL if none is found.
const chrome::BitmapFetcher* FindFetcherForUrl(const GURL& url);
// Remove |fetcher| from list of active fetchers. |fetcher| MUST be part of
// the list.
void RemoveFetcher(const chrome::BitmapFetcher* fetcher);
// BitmapFetcherDelegate implementation.
void OnFetchComplete(const GURL& url, const SkBitmap* bitmap) override;
// Currently active image fetchers.
BitmapFetchers active_fetchers_;
// Currently active requests.
ScopedVector<BitmapFetcherRequest> requests_;
// Cache of retrieved images.
struct CacheEntry {
CacheEntry();
~CacheEntry();
scoped_ptr<const SkBitmap> bitmap;
};
base::OwningMRUCache<GURL, CacheEntry*> cache_;
// Current request ID to be used.
int current_request_id_;
// Browser context this service is active for.
content::BrowserContext* context_;
DISALLOW_COPY_AND_ASSIGN(BitmapFetcherService);
};
#endif // CHROME_BROWSER_BITMAP_FETCHER_BITMAP_FETCHER_SERVICE_H_
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