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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_DATA_SOURCE_H_
#define MEDIA_BASE_DATA_SOURCE_H_
#include <stdint.h>
#include "base/containers/span.h"
#include "base/functional/callback_forward.h"
#include "media/base/media_export.h"
#include "url/gurl.h"
namespace media {
class CrossOriginDataSource;
// Abstracting informational methods into DataSourceInfo allows
// "meta-datasource" objects like HlsDataSourceProvider to query it's entire
// set of dependent data sources when calculating the data here.
class MEDIA_EXPORT DataSourceInfo {
public:
virtual ~DataSourceInfo();
// The total memory size used.
virtual int64_t GetMemoryUsage() = 0;
// DataSource implementations that might make requests must ensure the value
// is accurate for cross origin resources.
virtual bool WouldTaintOrigin() = 0;
// Returns true if we are performing streaming. In this case seeking is
// not possible.
virtual bool IsStreaming() = 0;
};
class MEDIA_EXPORT DataSource : public DataSourceInfo {
public:
using ReadCB = base::OnceCallback<void(int)>;
enum { kReadError = -1, kAborted = -2 };
// Used to specify video preload states. They are "hints" to the browser about
// how aggressively the browser should load and buffer data.
// Please see the HTML5 spec for the descriptions of these values:
// http://www.w3.org/TR/html5/video.html#attr-media-preload
//
// Enum values must match the values in WebMediaPlayer::Preload and
// there will be assertions at compile time if they do not match.
enum Preload {
NONE,
METADATA,
AUTO,
};
DataSource();
DataSource(const DataSource&) = delete;
DataSource& operator=(const DataSource&) = delete;
~DataSource() override;
// Reads `data.size()` bytes from `position` into `data`. And when the read
// is done or failed, `read_cb` is called with the number of bytes read or
// kReadError in case of error.
virtual void Read(int64_t position,
base::span<uint8_t> data,
DataSource::ReadCB read_cb) = 0;
// Stops the DataSource. Once this is called all future Read() calls will
// return an error. This is a synchronous call and may be called from any
// thread. Once called, the DataSource may no longer be used and should be
// destructed shortly thereafter.
virtual void Stop() = 0;
// Similar to Stop(), but only aborts current reads and not future reads.
virtual void Abort() = 0;
// Returns true and the file size, false if the file size could not be
// retrieved.
[[nodiscard]] virtual bool GetSize(int64_t* size_out) = 0;
// Notify the DataSource of the bitrate of the media.
// Values of |bitrate| <= 0 are invalid and should be ignored.
virtual void SetBitrate(int bitrate) = 0;
// If there is a MultiBuffer associated with this data source, then defer to
// it. This will return false if any HTTP response so far has failed the TAO
// check.
virtual bool PassedTimingAllowOriginCheck() = 0;
// Assume fully buffered by default.
virtual bool AssumeFullyBuffered() const;
// By default this just returns GetSize().
int64_t GetMemoryUsage() override;
// Adjusts the buffering algorithm (if there is one) based on the given
// preload value.
virtual void SetPreload(media::DataSource::Preload preload);
// Gets the url for this data source, if it exists. By default this returns
// an empty GURL.
virtual GURL GetUrlAfterRedirects() const;
// Stops any outstanding speculative loading. Active and future Read() calls
// will not be stopped. OnMediaIsPlaying() or OnMediaPlaybackRateChanged()
// with a rate > 0 will reset this flag.
virtual void StopPreloading();
// Allows a holder to notify certain events to the data source. Most data
// sources won't care too much about these events though.
virtual void OnMediaPlaybackRateChanged(double playback_rate);
virtual void OnMediaIsPlaying();
// Gets a CrossOriginDataSource version of |this|, or nullptr if it isn't one.
virtual CrossOriginDataSource* GetAsCrossOriginDataSource();
};
} // namespace media
#endif // MEDIA_BASE_DATA_SOURCE_H_
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