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// Copyright 2011 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 IOS_CHROME_BROWSER_NET_IMAGE_FETCHER_H_
#define IOS_CHROME_BROWSER_NET_IMAGE_FETCHER_H_
#include <map>
#include "base/mac/scoped_block.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "net/url_request/url_fetcher_delegate.h"
#include "net/url_request/url_request.h"
class GURL;
@class NSData;
namespace base {
class TaskRunner;
}
namespace net {
class URLRequestContextGetter;
}
namespace image_fetcher {
// Callback that informs of the download of an image encoded in |data|,
// downloaded from |url|, and with the http status |http_response_code|. If the
// url is a data URL, |http_response_code| is always 200.
using ImageFetchedCallback =
void (^)(const GURL& url, int http_response_code, NSData* data);
// Utility class that will retrieve an image from an URL. The image is returned
// as NSData which can be used with +[UIImage imageWithData:]. This class
// usually returns the raw bytes retrieved from the network without any
// processing, with the exception of WebP encoded images. Those are decoded and
// then reencoded in a format suitable for UIImage.
// An instance of this class can download a number of images at the same time.
class ImageFetcher : public net::URLFetcherDelegate {
public:
// The TaskRunner is used to eventually decode the image.
explicit ImageFetcher(const scoped_refptr<base::TaskRunner>& task_runner);
~ImageFetcher() override;
// Start downloading the image at the given |url|. The |callback| will be
// called with the downloaded image, or nil if any error happened. The
// |referrer| and |referrer_policy| will be passed on to the underlying
// URLFetcher.
// This method assumes the request context getter has been set.
// (virtual for testing)
virtual void StartDownload(const GURL& url,
ImageFetchedCallback callback,
const std::string& referrer,
net::URLRequest::ReferrerPolicy referrer_policy);
// Helper method to call StartDownload without a referrer.
// (virtual for testing)
virtual void StartDownload(const GURL& url, ImageFetchedCallback callback);
// A valid request context getter is required before starting the download.
// (virtual for testing)
virtual void SetRequestContextGetter(const scoped_refptr<
net::URLRequestContextGetter>& request_context_getter);
// net::URLFetcherDelegate:
void OnURLFetchComplete(const net::URLFetcher* source) override;
private:
// Runs the callback with the given arguments.
void RunCallback(const base::mac::ScopedBlock<ImageFetchedCallback>& callback,
const GURL& url,
const int http_response_code,
NSData* data);
// Tracks open download requests. The key is the URLFetcher object doing the
// fetch; the value is the callback to use when the download request
// completes. When a download request completes, the URLFetcher must be
// deleted and the callback called and released.
std::map<const net::URLFetcher*, ImageFetchedCallback> downloads_in_progress_;
scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
// The task runner used to decode images if necessary.
const scoped_refptr<base::TaskRunner> task_runner_;
// The WeakPtrFactory is used to cancel callbacks if ImageFetcher is destroyed
// during WebP decoding.
base::WeakPtrFactory<ImageFetcher> weak_factory_;
};
} // namespace image_fetcher
#endif // IOS_CHROME_BROWSER_NET_IMAGE_FETCHER_H_
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