gecko-dev/dom/media/MediaResource.h
Gerald Squelart f17dd305d6 Bug 1331289 - Use MediaContainerType in MediaResource, SourceBuffer, TrackBuffersManager, and dependencies - r=jya
Continuing the work of replacing MIME strings with MediaContainerType, starting
from MediaResource and following the dependencies.

Most changes are mechanical: Just change ns*String into MediaContainerType, and
MIME string literals into MEDIAMIMETYPE("a/b").
Some checks for empty/invalid strings and lowercase comparisons can go, thanks
to the always-valid always-lowercase-MIME invariants of MediaContainerType.

One special case in is MediaSourceResource, which used to have an empty string
as its type (because its own type is not relevant, but its SourceBuffers carry
types). Because the inherited GetContentType *must* be overridden, and must
return a MediaContainerType, we needed a valid type even though it should not
be seen in the real world. I've chosen "application/x.mediasource" for that.

MozReview-Commit-ID: 1aCH75Kh2e6

--HG--
extra : rebase_source : 0d9cd9b69c264e5dcfc3845f80ee107f4bcbcd9a
2016-12-28 18:59:02 +11:00

819 lines
31 KiB
C++

/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#if !defined(MediaResource_h_)
#define MediaResource_h_
#include "mozilla/Mutex.h"
#include "nsIChannel.h"
#include "nsIURI.h"
#include "nsISeekableStream.h"
#include "nsIStreamingProtocolController.h"
#include "nsIStreamListener.h"
#include "nsIChannelEventSink.h"
#include "nsIInterfaceRequestor.h"
#include "Intervals.h"
#include "MediaCache.h"
#include "MediaContainerType.h"
#include "MediaData.h"
#include "MediaResourceCallback.h"
#include "mozilla/Atomics.h"
#include "mozilla/Attributes.h"
#include "mozilla/TimeStamp.h"
#include "nsThreadUtils.h"
#include <algorithm>
// For HTTP seeking, if number of bytes needing to be
// seeked forward is less than this value then a read is
// done rather than a byte range request.
//
// If we assume a 100Mbit connection, and assume reissuing an HTTP seek causes
// a delay of 200ms, then in that 200ms we could have simply read ahead 2MB. So
// setting SEEK_VS_READ_THRESHOLD to 1MB sounds reasonable.
static const int64_t SEEK_VS_READ_THRESHOLD = 1 * 1024 * 1024;
static const uint32_t HTTP_REQUESTED_RANGE_NOT_SATISFIABLE_CODE = 416;
// Number of bytes we have accumulated before we assume the connection download
// rate can be reliably calculated. 57 Segments at IW=3 allows slow start to
// reach a CWND of 30 (See bug 831998)
static const int64_t RELIABLE_DATA_THRESHOLD = 57 * 1460;
class nsIHttpChannel;
class nsIPrincipal;
namespace mozilla {
class MediaChannelStatistics;
/**
* This class is useful for estimating rates of data passing through
* some channel. The idea is that activity on the channel "starts"
* and "stops" over time. At certain times data passes through the
* channel (usually while the channel is active; data passing through
* an inactive channel is ignored). The GetRate() function computes
* an estimate of the "current rate" of the channel, which is some
* kind of average of the data passing through over the time the
* channel is active.
*
* All methods take "now" as a parameter so the user of this class can
* control the timeline used.
*/
class MediaChannelStatistics {
public:
MediaChannelStatistics()
: mAccumulatedBytes(0)
, mIsStarted(false)
{
Reset();
}
explicit MediaChannelStatistics(MediaChannelStatistics * aCopyFrom)
{
MOZ_ASSERT(aCopyFrom);
mAccumulatedBytes = aCopyFrom->mAccumulatedBytes;
mAccumulatedTime = aCopyFrom->mAccumulatedTime;
mLastStartTime = aCopyFrom->mLastStartTime;
mIsStarted = aCopyFrom->mIsStarted;
}
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaChannelStatistics)
void Reset() {
mLastStartTime = TimeStamp();
mAccumulatedTime = TimeDuration(0);
mAccumulatedBytes = 0;
mIsStarted = false;
}
void Start() {
if (mIsStarted)
return;
mLastStartTime = TimeStamp::Now();
mIsStarted = true;
}
void Stop() {
if (!mIsStarted)
return;
mAccumulatedTime += TimeStamp::Now() - mLastStartTime;
mIsStarted = false;
}
void AddBytes(int64_t aBytes) {
if (!mIsStarted) {
// ignore this data, it may be related to seeking or some other
// operation we don't care about
return;
}
mAccumulatedBytes += aBytes;
}
double GetRateAtLastStop(bool* aReliable) {
double seconds = mAccumulatedTime.ToSeconds();
*aReliable = (seconds >= 1.0) ||
(mAccumulatedBytes >= RELIABLE_DATA_THRESHOLD);
if (seconds <= 0.0)
return 0.0;
return static_cast<double>(mAccumulatedBytes)/seconds;
}
double GetRate(bool* aReliable) {
TimeDuration time = mAccumulatedTime;
if (mIsStarted) {
time += TimeStamp::Now() - mLastStartTime;
}
double seconds = time.ToSeconds();
*aReliable = (seconds >= 3.0) ||
(mAccumulatedBytes >= RELIABLE_DATA_THRESHOLD);
if (seconds <= 0.0)
return 0.0;
return static_cast<double>(mAccumulatedBytes)/seconds;
}
private:
~MediaChannelStatistics() {}
int64_t mAccumulatedBytes;
TimeDuration mAccumulatedTime;
TimeStamp mLastStartTime;
bool mIsStarted;
};
// Represents a section of contiguous media, with a start and end offset.
// Used to denote ranges of data which are cached.
typedef media::Interval<int64_t> MediaByteRange;
typedef media::IntervalSet<int64_t> MediaByteRangeSet;
/**
* Provides a thread-safe, seek/read interface to resources
* loaded from a URI. Uses MediaCache to cache data received over
* Necko's async channel API, thus resolving the mismatch between clients
* that need efficient random access to the data and protocols that do not
* support efficient random access, such as HTTP.
*
* Instances of this class must be created on the main thread.
* Most methods must be called on the main thread only. Read, Seek and
* Tell must only be called on non-main threads. In the case of the Ogg
* Decoder they are called on the Decode thread for example. You must
* ensure that no threads are calling these methods once Close is called.
*
* Instances of this class are reference counted. Use nsRefPtr for
* managing the lifetime of instances of this class.
*
* The generic implementation of this class is ChannelMediaResource, which can
* handle any URI for which Necko supports AsyncOpen.
* The 'file:' protocol can be implemented efficiently with direct random
* access, so the FileMediaResource implementation class bypasses the cache.
* MediaResource::Create automatically chooses the best implementation class.
*/
class MediaResource : public nsISupports
{
public:
// Our refcounting is threadsafe, and when our refcount drops to zero
// we dispatch an event to the main thread to delete the MediaResource.
// Note that this means it's safe for references to this object to be
// released on a non main thread, but the destructor will always run on
// the main thread.
NS_DECL_THREADSAFE_ISUPPORTS
// The following can be called on the main thread only:
// Get the URI
virtual nsIURI* URI() const { return nullptr; }
// Close the resource, stop any listeners, channels, etc.
// Cancels any currently blocking Read request and forces that request to
// return an error.
virtual nsresult Close() = 0;
// Suspend any downloads that are in progress.
// If aCloseImmediately is set, resources should be released immediately
// since we don't expect to resume again any time soon. Otherwise we
// may resume again soon so resources should be held for a little
// while.
virtual void Suspend(bool aCloseImmediately) = 0;
// Resume any downloads that have been suspended.
virtual void Resume() = 0;
// Get the current principal for the channel
virtual already_AddRefed<nsIPrincipal> GetCurrentPrincipal() = 0;
// If this returns false, then we shouldn't try to clone this MediaResource
// because its underlying resources are not suitable for reuse (e.g.
// because the underlying connection has been lost, or this resource
// just can't be safely cloned). If this returns true, CloneData could
// still fail. If this returns false, CloneData should not be called.
virtual bool CanClone() { return false; }
// Create a new stream of the same type that refers to the same URI
// with a new channel. Any cached data associated with the original
// stream should be accessible in the new stream too.
virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback* aCallback) = 0;
// Set statistics to be recorded to the object passed in.
virtual void RecordStatisticsTo(MediaChannelStatistics *aStatistics) { }
// These methods are called off the main thread.
// The mode is initially MODE_PLAYBACK.
virtual void SetReadMode(MediaCacheStream::ReadMode aMode) = 0;
// This is the client's estimate of the playback rate assuming
// the media plays continuously. The cache can't guess this itself
// because it doesn't know when the decoder was paused, buffering, etc.
virtual void SetPlaybackRate(uint32_t aBytesPerSecond) = 0;
// Read up to aCount bytes from the stream. The read starts at
// aOffset in the stream, seeking to that location initially if
// it is not the current stream offset. The remaining arguments,
// results and requirements are the same as per the Read method.
virtual nsresult ReadAt(int64_t aOffset, char* aBuffer,
uint32_t aCount, uint32_t* aBytes) = 0;
// This method returns nullptr if anything fails.
// Otherwise, it returns an owned buffer.
// MediaReadAt may return fewer bytes than requested if end of stream is
// encountered. There is no need to call it again to get more data.
virtual already_AddRefed<MediaByteBuffer> MediaReadAt(int64_t aOffset, uint32_t aCount)
{
RefPtr<MediaByteBuffer> bytes = new MediaByteBuffer();
bool ok = bytes->SetLength(aCount, fallible);
NS_ENSURE_TRUE(ok, nullptr);
char* curr = reinterpret_cast<char*>(bytes->Elements());
const char* start = curr;
while (aCount > 0) {
uint32_t bytesRead;
nsresult rv = ReadAt(aOffset, curr, aCount, &bytesRead);
NS_ENSURE_SUCCESS(rv, nullptr);
if (!bytesRead) {
break;
}
aOffset += bytesRead;
aCount -= bytesRead;
curr += bytesRead;
}
bytes->SetLength(curr - start);
return bytes.forget();
}
// Report the current offset in bytes from the start of the stream.
// This is used to approximate where we currently are in the playback of a
// media.
// A call to ReadAt will update this position.
virtual int64_t Tell() = 0;
// Moves any existing channel loads into or out of background. Background
// loads don't block the load event. This also determines whether or not any
// new loads initiated (for example to seek) will be in the background.
virtual void SetLoadInBackground(bool aLoadInBackground) {}
// Ensures that the value returned by IsSuspendedByCache below is up to date
// (i.e. the cache has examined this stream at least once).
virtual void EnsureCacheUpToDate() {}
// These can be called on any thread.
// Cached blocks associated with this stream will not be evicted
// while the stream is pinned.
virtual void Pin() = 0;
virtual void Unpin() = 0;
// Get the estimated download rate in bytes per second (assuming no
// pausing of the channel is requested by Gecko).
// *aIsReliable is set to true if we think the estimate is useful.
virtual double GetDownloadRate(bool* aIsReliable) = 0;
// Get the length of the stream in bytes. Returns -1 if not known.
// This can change over time; after a seek operation, a misbehaving
// server may give us a resource of a different length to what it had
// reported previously --- or it may just lie in its Content-Length
// header and give us more or less data than it reported. We will adjust
// the result of GetLength to reflect the data that's actually arriving.
virtual int64_t GetLength() = 0;
// Returns the offset of the first byte of cached data at or after aOffset,
// or -1 if there is no such cached data.
virtual int64_t GetNextCachedData(int64_t aOffset) = 0;
// Returns the end of the bytes starting at the given offset
// which are in cache.
virtual int64_t GetCachedDataEnd(int64_t aOffset) = 0;
// Returns true if all the data from aOffset to the end of the stream
// is in cache. If the end of the stream is not known, we return false.
virtual bool IsDataCachedToEndOfResource(int64_t aOffset) = 0;
// Returns true if we are expecting any more data to arrive
// sometime in the not-too-distant future, either from the network or from
// an appendBuffer call on a MediaSource element.
virtual bool IsExpectingMoreData()
{
// MediaDecoder::mDecoderPosition is roughly the same as Tell() which
// returns a position updated by latest Read() or ReadAt().
return !IsDataCachedToEndOfResource(Tell()) && !IsSuspended();
}
// Returns true if this stream is suspended by the cache because the
// cache is full. If true then the decoder should try to start consuming
// data, otherwise we may not be able to make progress.
// MediaDecoder::NotifySuspendedStatusChanged is called when this
// changes.
// For resources using the media cache, this returns true only when all
// streams for the same resource are all suspended.
virtual bool IsSuspendedByCache() = 0;
// Returns true if this stream has been suspended.
virtual bool IsSuspended() = 0;
// Reads only data which is cached in the media cache. If you try to read
// any data which overlaps uncached data, or if aCount bytes otherwise can't
// be read, this function will return failure. This function be called from
// any thread, and it is the only read operation which is safe to call on
// the main thread, since it's guaranteed to be non blocking.
virtual nsresult ReadFromCache(char* aBuffer,
int64_t aOffset,
uint32_t aCount) = 0;
// Returns true if the resource can be seeked to unbuffered ranges, i.e.
// for an HTTP network stream this returns true if HTTP1.1 Byte Range
// requests are supported by the connection/server.
virtual bool IsTransportSeekable() = 0;
/**
* Create a resource, reading data from the channel. Call on main thread only.
* The caller must follow up by calling resource->Open().
*/
static already_AddRefed<MediaResource> Create(MediaResourceCallback* aCallback, nsIChannel* aChannel);
/**
* Open the stream. This creates a stream listener and returns it in
* aStreamListener; this listener needs to be notified of incoming data.
*/
virtual nsresult Open(nsIStreamListener** aStreamListener) = 0;
/**
* Fills aRanges with MediaByteRanges representing the data which is cached
* in the media cache. Stream should be pinned during call and while
* aRanges is being used.
*/
virtual nsresult GetCachedRanges(MediaByteRangeSet& aRanges) = 0;
// Ensure that the media cache writes any data held in its partial block.
// Called on the main thread only.
virtual void FlushCache() { }
// Notify that the last data byte range was loaded.
virtual void NotifyLastByteRange() { }
// Returns the container content type of the resource. This is copied from the
// nsIChannel when the MediaResource is created. Safe to call from
// any thread.
virtual const MediaContainerType& GetContentType() const = 0;
// Return true if the stream is a live stream
virtual bool IsRealTime() {
return false;
}
// Returns true if the resource is a live stream.
virtual bool IsLiveStream()
{
return GetLength() == -1;
}
virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
return 0;
}
virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
const nsCString& GetContentURL() const { return EmptyCString(); }
protected:
virtual ~MediaResource() {};
private:
void Destroy();
};
class BaseMediaResource : public MediaResource {
public:
nsIURI* URI() const override { return mURI; }
void SetLoadInBackground(bool aLoadInBackground) override;
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
{
// Might be useful to track in the future:
// - mChannel
// - mURI (possibly owned, looks like just a ref from mChannel)
// Not owned:
// - mCallback
size_t size = MediaResource::SizeOfExcludingThis(aMallocSizeOf);
size += mContainerType.SizeOfExcludingThis(aMallocSizeOf);
return size;
}
size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
{
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
// Returns the url of the resource. Safe to call from any thread?
const nsCString& GetContentURL() const
{
return mContentURL;
}
protected:
BaseMediaResource(MediaResourceCallback* aCallback,
nsIChannel* aChannel,
nsIURI* aURI,
const MediaContainerType& aContainerType) :
mCallback(aCallback),
mChannel(aChannel),
mURI(aURI),
mContainerType(aContainerType),
mLoadInBackground(false)
{
mURI->GetSpec(mContentURL);
}
virtual ~BaseMediaResource()
{
}
const MediaContainerType& GetContentType() const override
{
return mContainerType;
}
// Set the request's load flags to aFlags. If the request is part of a
// load group, the request is removed from the group, the flags are set, and
// then the request is added back to the load group.
void ModifyLoadFlags(nsLoadFlags aFlags);
// Dispatches an event to call MediaDecoder::NotifyBytesConsumed(aNumBytes, aOffset)
// on the main thread. This is called automatically after every read.
void DispatchBytesConsumed(int64_t aNumBytes, int64_t aOffset);
RefPtr<MediaResourceCallback> mCallback;
// Channel used to download the media data. Must be accessed
// from the main thread only.
nsCOMPtr<nsIChannel> mChannel;
// URI in case the stream needs to be re-opened. Access from
// main thread only.
nsCOMPtr<nsIURI> mURI;
// Content-Type of the channel. This is copied from the nsIChannel when the
// MediaResource is created. This is constant, so accessing from any thread
// is safe.
const MediaContainerType mContainerType;
// Copy of the url of the channel resource.
nsCString mContentURL;
// True if SetLoadInBackground() has been called with
// aLoadInBackground = true, i.e. when the document load event is not
// blocked by this resource, and all channel loads will be in the
// background.
bool mLoadInBackground;
};
/**
* This class is responsible for managing the suspend count and report suspend
* status of channel.
**/
class ChannelSuspendAgent {
public:
explicit ChannelSuspendAgent(nsIChannel* aChannel)
: mChannel(aChannel),
mSuspendCount(0),
mIsChannelSuspended(false)
{}
// True when the channel has been suspended or needs to be suspended.
bool IsSuspended();
// Return true when the channel is logically suspended, i.e. the suspend
// count goes from 0 to 1.
bool Suspend();
// Return true only when the suspend count is equal to zero.
bool Resume();
// Call after opening channel, set channel and check whether the channel
// needs to be suspended.
void NotifyChannelOpened(nsIChannel* aChannel);
// Call before closing channel, reset the channel internal status if needed.
void NotifyChannelClosing();
// Check whether we need to suspend the channel.
void UpdateSuspendedStatusIfNeeded();
private:
// Only suspends channel but not changes the suspend count.
void SuspendInternal();
nsIChannel* mChannel;
Atomic<uint32_t> mSuspendCount;
bool mIsChannelSuspended;
};
/**
* This is the MediaResource implementation that wraps Necko channels.
* Much of its functionality is actually delegated to MediaCache via
* an underlying MediaCacheStream.
*
* All synchronization is performed by MediaCacheStream; all off-main-
* thread operations are delegated directly to that object.
*/
class ChannelMediaResource : public BaseMediaResource
{
public:
ChannelMediaResource(MediaResourceCallback* aDecoder,
nsIChannel* aChannel,
nsIURI* aURI,
const MediaContainerType& aContainerType);
~ChannelMediaResource();
// These are called on the main thread by MediaCache. These must
// not block or grab locks, because the media cache is holding its lock.
// Notify that data is available from the cache. This can happen even
// if this stream didn't read any data, since another stream might have
// received data for the same resource.
void CacheClientNotifyDataReceived();
// Notify that we reached the end of the stream. This can happen even
// if this stream didn't read any data, since another stream might have
// received data for the same resource.
void CacheClientNotifyDataEnded(nsresult aStatus);
// Notify that the principal for the cached resource changed.
void CacheClientNotifyPrincipalChanged();
// Notify the decoder that the cache suspended status changed.
void CacheClientNotifySuspendedStatusChanged();
// These are called on the main thread by MediaCache. These shouldn't block,
// but they may grab locks --- the media cache is not holding its lock
// when these are called.
// Start a new load at the given aOffset. The old load is cancelled
// and no more data from the old load will be notified via
// MediaCacheStream::NotifyDataReceived/Ended.
// This can fail.
nsresult CacheClientSeek(int64_t aOffset, bool aResume);
// Suspend the current load since data is currently not wanted
nsresult CacheClientSuspend();
// Resume the current load since data is wanted again
nsresult CacheClientResume();
// Ensure that the media cache writes any data held in its partial block.
// Called on the main thread.
void FlushCache() override;
// Notify that the last data byte range was loaded.
void NotifyLastByteRange() override;
// Main thread
nsresult Open(nsIStreamListener** aStreamListener) override;
nsresult Close() override;
void Suspend(bool aCloseImmediately) override;
void Resume() override;
already_AddRefed<nsIPrincipal> GetCurrentPrincipal() override;
// Return true if the stream has been closed.
bool IsClosed() const { return mCacheStream.IsClosed(); }
bool CanClone() override;
already_AddRefed<MediaResource> CloneData(MediaResourceCallback* aDecoder) override;
// Set statistics to be recorded to the object passed in. If not called,
// |ChannelMediaResource| will create it's own statistics objects in |Open|.
void RecordStatisticsTo(MediaChannelStatistics *aStatistics) override {
NS_ASSERTION(aStatistics, "Statistics param cannot be null!");
MutexAutoLock lock(mLock);
if (!mChannelStatistics) {
mChannelStatistics = aStatistics;
}
}
nsresult ReadFromCache(char* aBuffer, int64_t aOffset, uint32_t aCount) override;
void EnsureCacheUpToDate() override;
// Other thread
void SetReadMode(MediaCacheStream::ReadMode aMode) override;
void SetPlaybackRate(uint32_t aBytesPerSecond) override;
nsresult ReadAt(int64_t offset, char* aBuffer,
uint32_t aCount, uint32_t* aBytes) override;
already_AddRefed<MediaByteBuffer> MediaReadAt(int64_t aOffset, uint32_t aCount) override;
int64_t Tell() override;
// Any thread
void Pin() override;
void Unpin() override;
double GetDownloadRate(bool* aIsReliable) override;
int64_t GetLength() override;
int64_t GetNextCachedData(int64_t aOffset) override;
int64_t GetCachedDataEnd(int64_t aOffset) override;
bool IsDataCachedToEndOfResource(int64_t aOffset) override;
bool IsSuspendedByCache() override;
bool IsSuspended() override;
bool IsTransportSeekable() override;
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override {
// Might be useful to track in the future:
// - mListener (seems minor)
// - mChannelStatistics (seems minor)
// owned if RecordStatisticsTo is not called
// - mDataReceivedEvent (seems minor)
size_t size = BaseMediaResource::SizeOfExcludingThis(aMallocSizeOf);
size += mCacheStream.SizeOfExcludingThis(aMallocSizeOf);
return size;
}
size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override {
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
class Listener final : public nsIStreamListener,
public nsIInterfaceRequestor,
public nsIChannelEventSink
{
~Listener() {}
public:
explicit Listener(ChannelMediaResource* aResource) : mResource(aResource) {}
NS_DECL_ISUPPORTS
NS_DECL_NSIREQUESTOBSERVER
NS_DECL_NSISTREAMLISTENER
NS_DECL_NSICHANNELEVENTSINK
NS_DECL_NSIINTERFACEREQUESTOR
void Revoke() { mResource = nullptr; }
private:
RefPtr<ChannelMediaResource> mResource;
};
friend class Listener;
nsresult GetCachedRanges(MediaByteRangeSet& aRanges) override;
protected:
// These are called on the main thread by Listener.
nsresult OnStartRequest(nsIRequest* aRequest);
nsresult OnStopRequest(nsIRequest* aRequest, nsresult aStatus);
nsresult OnDataAvailable(nsIRequest* aRequest,
nsIInputStream* aStream,
uint32_t aCount);
nsresult OnChannelRedirect(nsIChannel* aOld, nsIChannel* aNew, uint32_t aFlags);
// Opens the channel, using an HTTP byte range request to start at mOffset
// if possible. Main thread only.
nsresult OpenChannel(nsIStreamListener** aStreamListener);
nsresult RecreateChannel();
// Add headers to HTTP request. Main thread only.
nsresult SetupChannelHeaders();
// Closes the channel. Main thread only.
void CloseChannel();
// Parses 'Content-Range' header and returns results via parameters.
// Returns error if header is not available, values are not parse-able or
// values are out of range.
nsresult ParseContentRangeHeader(nsIHttpChannel * aHttpChan,
int64_t& aRangeStart,
int64_t& aRangeEnd,
int64_t& aRangeTotal);
void DoNotifyDataReceived();
static nsresult CopySegmentToCache(nsIInputStream *aInStream,
void *aClosure,
const char *aFromSegment,
uint32_t aToOffset,
uint32_t aCount,
uint32_t *aWriteCount);
// Main thread access only
int64_t mOffset;
RefPtr<Listener> mListener;
// A data received event for the decoder that has been dispatched but has
// not yet been processed.
nsRevocableEventPtr<nsRunnableMethod<ChannelMediaResource, void, false> > mDataReceivedEvent;
// When this flag is set, if we get a network error we should silently
// reopen the stream.
bool mReopenOnError;
// When this flag is set, we should not report the next close of the
// channel.
bool mIgnoreClose;
// Any thread access
MediaCacheStream mCacheStream;
// This lock protects mChannelStatistics
Mutex mLock;
RefPtr<MediaChannelStatistics> mChannelStatistics;
// True if we couldn't suspend the stream and we therefore don't want
// to resume later. This is usually due to the channel not being in the
// isPending state at the time of the suspend request.
bool mIgnoreResume;
ChannelSuspendAgent mSuspendAgent;
};
/**
* RAII class that handles pinning and unpinning for MediaResource and derived.
* This should be used when making calculations that involve potentially-cached
* MediaResource data, so that the state of the world can't change out from under
* us.
*/
template<class T>
class MOZ_RAII AutoPinned {
public:
explicit AutoPinned(T* aResource MOZ_GUARD_OBJECT_NOTIFIER_PARAM) : mResource(aResource) {
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
MOZ_ASSERT(mResource);
mResource->Pin();
}
~AutoPinned() {
mResource->Unpin();
}
operator T*() const { return mResource; }
T* operator->() const MOZ_NO_ADDREF_RELEASE_ON_RETURN { return mResource; }
private:
T* mResource;
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};
/*
* MediaResourceIndex provides a way to access MediaResource objects.
* Read, Seek and Tell must only be called on non-main threads.
* In the case of the Ogg Decoder they are called on the Decode thread for
* example. You must ensure that no threads are calling these methods once
* the MediaResource has been Closed.
*/
class MediaResourceIndex
{
public:
explicit MediaResourceIndex(MediaResource* aResource)
: mResource(aResource)
, mOffset(0)
{}
// Read up to aCount bytes from the stream. The buffer must have
// enough room for at least aCount bytes. Stores the number of
// actual bytes read in aBytes (0 on end of file).
// May read less than aCount bytes if the number of
// available bytes is less than aCount. Always check *aBytes after
// read, and call again if necessary.
nsresult Read(char* aBuffer, uint32_t aCount, uint32_t* aBytes);
// Seek to the given bytes offset in the stream. aWhence can be
// one of:
// NS_SEEK_SET
// NS_SEEK_CUR
// NS_SEEK_END
//
// In the Http strategy case the cancel will cause the http
// channel's listener to close the pipe, forcing an i/o error on any
// blocked read. This will allow the decode thread to complete the
// event.
//
// In the case of a seek in progress, the byte range request creates
// a new listener. This is done on the main thread via seek
// synchronously dispatching an event. This avoids the issue of us
// closing the listener but an outstanding byte range request
// creating a new one. They run on the same thread so no explicit
// synchronisation is required. The byte range request checks for
// the cancel flag and does not create a new channel or listener if
// we are cancelling.
//
// The default strategy does not do any seeking - the only issue is
// a blocked read which it handles by causing the listener to close
// the pipe, as per the http case.
//
// The file strategy doesn't block for any great length of time so
// is fine for a no-op cancel.
nsresult Seek(int32_t aWhence, int64_t aOffset);
// Report the current offset in bytes from the start of the stream.
int64_t Tell() const { return mOffset; }
// Return the underlying MediaResource.
MediaResource* GetResource() const { return mResource; }
// Read up to aCount bytes from the stream. The read starts at
// aOffset in the stream, seeking to that location initially if
// it is not the current stream offset.
// Unlike MediaResource::ReadAt, ReadAt only returns fewer bytes than
// requested if end of stream or an error is encountered. There is no need to
// call it again to get more data.
// *aBytes will contain the number of bytes copied, even if an error occurred.
// ReadAt doesn't have an impact on the offset returned by Tell().
nsresult ReadAt(int64_t aOffset, char* aBuffer,
uint32_t aCount, uint32_t* aBytes) const;
// Convenience methods, directly calling the MediaResource method of the same
// name.
// Those functions do not update the MediaResource offset as returned
// by Tell().
// This method returns nullptr if anything fails.
// Otherwise, it returns an owned buffer.
// MediaReadAt may return fewer bytes than requested if end of stream is
// encountered. There is no need to call it again to get more data.
already_AddRefed<MediaByteBuffer> MediaReadAt(int64_t aOffset, uint32_t aCount) const
{
return mResource->MediaReadAt(aOffset, aCount);
}
// Get the length of the stream in bytes. Returns -1 if not known.
// This can change over time; after a seek operation, a misbehaving
// server may give us a resource of a different length to what it had
// reported previously --- or it may just lie in its Content-Length
// header and give us more or less data than it reported. We will adjust
// the result of GetLength to reflect the data that's actually arriving.
int64_t GetLength() const { return mResource->GetLength(); }
private:
RefPtr<MediaResource> mResource;
int64_t mOffset;
};
} // namespace mozilla
#endif