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// Copyright 2015 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 MEDIA_BLINK_URL_INDEX_H_
#define MEDIA_BLINK_URL_INDEX_H_
#include <stddef.h>
#include <stdint.h>
#include <map>
#include <vector>
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/thread_checker.h"
#include "media/blink/lru.h"
#include "media/blink/media_blink_export.h"
#include "media/blink/multibuffer.h"
#include "third_party/WebKit/public/web/WebFrame.h"
#include "url/gurl.h"
namespace media {
const int64_t kPositionNotSpecified = -1;
class UrlData;
// A multibuffer for loading media resources which knows
// how to create MultiBufferDataProviders to load data
// into the cache.
class MEDIA_BLINK_EXPORT ResourceMultiBuffer
: NON_EXPORTED_BASE(public MultiBuffer) {
public:
ResourceMultiBuffer(UrlData* url_data_, int block_shift);
~ResourceMultiBuffer() override;
// MultiBuffer implementation.
std::unique_ptr<MultiBuffer::DataProvider> CreateWriter(
const BlockId& pos) override;
bool RangeSupported() const override;
void OnEmpty() override;
protected:
// Do not access from destructor, it is a pointer to the
// object that contains us.
UrlData* url_data_;
};
class UrlIndex;
// All the data & metadata for a single resource.
// Data is cached using a MultiBuffer instance.
class MEDIA_BLINK_EXPORT UrlData : public base::RefCounted<UrlData> {
public:
// Keep in sync with WebMediaPlayer::CORSMode.
enum CORSMode { CORS_UNSPECIFIED, CORS_ANONYMOUS, CORS_USE_CREDENTIALS };
typedef std::pair<GURL, CORSMode> KeyType;
// Accessors
const GURL& url() const { return url_; }
// Cross-origin access mode
CORSMode cors_mode() const { return cors_mode_; }
// Are HTTP range requests supported?
bool range_supported() const { return range_supported_; }
// True if we found a reason why this URL won't be stored in the
// HTTP disk cache.
bool cacheable() const { return cacheable_; }
// Last used time.
base::Time last_used() const { return last_used_; }
// Last modified time.
base::Time last_modified() const { return last_modified_; }
// Expiration time.
base::Time valid_until() const { return valid_until_; }
// The key used by UrlIndex to find this UrlData.
KeyType key() const;
// Length of data associated with url or |kPositionNotSpecified|
int64_t length() const { return length_; }
// Returns the number of blocks cached for this resource.
size_t CachedSize();
// Returns our url_index, or nullptr if it's been destroyed.
UrlIndex* url_index() const { return url_index_.get(); }
// Notifies the url index that this is currently used.
// The url <-> URLData mapping will be eventually be invalidated if
// this is not called regularly.
void Use();
// Setters.
void set_length(int64_t length);
void set_cacheable(bool cacheable);
void set_valid_until(base::Time valid_until);
void set_range_supported();
void set_last_modified(base::Time last_modified);
// A redirect has occured (or we've found a better UrlData for the same
// resource).
void RedirectTo(const scoped_refptr<UrlData>& to);
// Fail, tell all clients that a failure has occured.
void Fail();
// Callback for receving notifications when a redirect occurs.
typedef base::Callback<void(const scoped_refptr<UrlData>&)> RedirectCB;
// Register a callback to be called when a redirect occurs.
// Callbacks are cleared when a redirect occurs, so clients must call
// OnRedirect again if they wish to continue receiving callbacks.
void OnRedirect(const RedirectCB& cb);
// Returns true it is valid to keep using this to access cached data.
// A single media player instance may choose to ignore this for resources
// that have already been opened.
bool Valid() const;
// Virtual so we can override it for testing.
virtual ResourceMultiBuffer* multibuffer();
// Accessor
blink::WebFrame* frame() const { return frame_; }
protected:
UrlData(const GURL& url,
CORSMode cors_mode,
const base::WeakPtr<UrlIndex>& url_index);
virtual ~UrlData();
private:
friend class ResourceMultiBuffer;
friend class UrlIndex;
friend class base::RefCounted<UrlData>;
void OnEmpty();
void MergeFrom(const scoped_refptr<UrlData>& other);
// Url we represent, note that there may be multiple UrlData for
// the same url.
const GURL url_;
// Cross-origin access mode.
const CORSMode cors_mode_;
base::WeakPtr<UrlIndex> url_index_;
// Length of resource this url points to. (in bytes)
int64_t length_;
// Does the server support ranges?
bool range_supported_;
// Set to false if we have reason to beleive the chrome disk cache
// will not cache this url.
bool cacheable_;
// Last time some media time used this resource.
// Note that we use base::Time rather than base::TimeTicks because
// TimeTicks will stop advancing when a machine goes to sleep.
// base::Time can go backwards, jump hours at a time and be generally
// unpredictable, but it doesn't stop, which is preferable here.
// (False negatives are better than false positivies.)
base::Time last_used_;
// Expiration time according to http headers.
base::Time valid_until_;
// Last modification time according to http headers.
base::Time last_modified_;
ResourceMultiBuffer multibuffer_;
std::vector<RedirectCB> redirect_callbacks_;
blink::WebFrame* frame_;
base::ThreadChecker thread_checker_;
DISALLOW_COPY_AND_ASSIGN(UrlData);
};
// The UrlIndex lets you look up UrlData instances by url.
class MEDIA_BLINK_EXPORT UrlIndex {
public:
explicit UrlIndex(blink::WebFrame*);
UrlIndex(blink::WebFrame*, int block_shift);
virtual ~UrlIndex();
// Look up an UrlData in the index and return it. If none is found,
// create a new one. Note that newly created UrlData entries are NOT
// added to the index, instead you must call TryInsert on them after
// initializing relevant parameters, like whether it support
// ranges and it's last modified time.
scoped_refptr<UrlData> GetByUrl(const GURL& gurl,
UrlData::CORSMode cors_mode);
// Add the given UrlData to the index if possible. If a better UrlData
// is already present in the index, return it instead. (If not, we just
// return the given UrlData.) Please make sure to initialize all the data
// that can be gathered from HTTP headers in |url_data| before calling this.
// In particular, the following fields are important:
// o range_supported: Entries which do not support ranges cannot be
// shared and are not added to the index.
// o valid_until, last_used: Entries have to be valid to be inserted
// into the index, this means that they have to have been recently
// used or have an Expires: header that says when they stop being valid.
// o last_modified: Expired cache entries can be re-used if last_modified
// matches.
// TODO(hubbe): Add etag support.
scoped_refptr<UrlData> TryInsert(const scoped_refptr<UrlData>& url_data);
blink::WebFrame* frame() const { return frame_; }
int block_shift() const { return block_shift_; }
private:
friend class UrlData;
friend class ResourceMultiBuffer;
void RemoveUrlDataIfEmpty(const scoped_refptr<UrlData>& url_data);
// Virtual so we can override it in tests.
virtual scoped_refptr<UrlData> NewUrlData(const GURL& url,
UrlData::CORSMode cors_mode);
std::map<UrlData::KeyType, scoped_refptr<UrlData>> by_url_;
blink::WebFrame* frame_;
scoped_refptr<MultiBuffer::GlobalLRU> lru_;
// log2 of block size in multibuffer cache. Defaults to kBlockSizeShift.
// Currently only changed for testing purposes.
const int block_shift_;
protected:
base::WeakPtrFactory<UrlIndex> weak_factory_;
};
} // namespace media
#endif // MEDIA_BLINK_URL_INDEX_H_