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gecko-dev/dom/media/MediaCache.cpp
Nicholas Nethercote 18fae65f38 Bug 1563139 - Remove StaticPrefs.h. r=glandium 
This requires replacing inclusions of it with inclusions of more specific prefs
files.

The exception is that StaticPrefsAll.h, which is equivalent to StaticPrefs.h,
and is used in `Codegen.py` because doing something smarter is tricky and
suitable for a follow-up. As a result, any change to StaticPrefList.yaml will
still trigger recompilation of all the generated DOM bindings files, but that's
still a big improvement over trigger recompilation of every file that uses
static prefs.

Most of the changes in this commit are very boring. The only changes that are
not boring are modules/libpref/*, Codegen.py, and ServoBindings.toml.

Differential Revision: https://phabricator.services.mozilla.com/D39138

--HG--
extra : moz-landing-system : lando
2019-07-26 01:10:23 +00:00

2795 lines
102 KiB
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include "MediaCache.h"
#include "ChannelMediaResource.h"
#include "FileBlockCache.h"
#include "MediaBlockCacheBase.h"
#include "MediaResource.h"
#include "MemoryBlockCache.h"
#include "mozilla/Attributes.h"
#include "mozilla/ClearOnShutdown.h"
#include "mozilla/ErrorNames.h"
#include "mozilla/Logging.h"
#include "mozilla/Monitor.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/StaticPrefs_media.h"
#include "mozilla/SystemGroup.h"
#include "mozilla/Telemetry.h"
#include "nsContentUtils.h"
#include "nsINetworkLinkService.h"
#include "nsIObserverService.h"
#include "nsIPrincipal.h"
#include "nsPrintfCString.h"
#include "nsProxyRelease.h"
#include "nsThreadUtils.h"
#include "prio.h"
#include "VideoUtils.h"
#include <algorithm>
namespace mozilla {
#undef LOG
#undef LOGI
#undef LOGE
LazyLogModule gMediaCacheLog("MediaCache");
#define LOG(...) MOZ_LOG(gMediaCacheLog, LogLevel::Debug, (__VA_ARGS__))
#define LOGI(...) MOZ_LOG(gMediaCacheLog, LogLevel::Info, (__VA_ARGS__))
#define LOGE(...) \
NS_DebugBreak(NS_DEBUG_WARNING, nsPrintfCString(__VA_ARGS__).get(), nullptr, \
__FILE__, __LINE__)
// 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;
// Readahead blocks for non-seekable streams will be limited to this
// fraction of the cache space. We don't normally evict such blocks
// because replacing them requires a seek, but we need to make sure
// they don't monopolize the cache.
static const double NONSEEKABLE_READAHEAD_MAX = 0.5;
// Data N seconds before the current playback position is given the same
// priority as data REPLAY_PENALTY_FACTOR*N seconds ahead of the current
// playback position. REPLAY_PENALTY_FACTOR is greater than 1 to reflect that
// data in the past is less likely to be played again than data in the future.
// We want to give data just behind the current playback position reasonably
// high priority in case codecs need to retrieve that data (e.g. because
// tracks haven't been muxed well or are being decoded at uneven rates).
// 1/REPLAY_PENALTY_FACTOR as much data will be kept behind the
// current playback position as will be kept ahead of the current playback
// position.
static const uint32_t REPLAY_PENALTY_FACTOR = 3;
// When looking for a reusable block, scan forward this many blocks
// from the desired "best" block location to look for free blocks,
// before we resort to scanning the whole cache. The idea is to try to
// store runs of stream blocks close-to-consecutively in the cache if we
// can.
static const uint32_t FREE_BLOCK_SCAN_LIMIT = 16;
#ifdef DEBUG
// Turn this on to do very expensive cache state validation
// #define DEBUG_VERIFY_CACHE
#endif
class MediaCacheFlusher final : public nsIObserver,
public nsSupportsWeakReference {
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
static void RegisterMediaCache(MediaCache* aMediaCache);
static void UnregisterMediaCache(MediaCache* aMediaCache);
private:
MediaCacheFlusher() {}
~MediaCacheFlusher() {}
// Singleton instance created when a first MediaCache is registered, and
// released when the last MediaCache is unregistered.
// The observer service will keep a weak reference to it, for notifications.
static StaticRefPtr<MediaCacheFlusher> gMediaCacheFlusher;
nsTArray<MediaCache*> mMediaCaches;
};
/* static */
StaticRefPtr<MediaCacheFlusher> MediaCacheFlusher::gMediaCacheFlusher;
NS_IMPL_ISUPPORTS(MediaCacheFlusher, nsIObserver, nsISupportsWeakReference)
/* static */
void MediaCacheFlusher::RegisterMediaCache(MediaCache* aMediaCache) {
NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
if (!gMediaCacheFlusher) {
gMediaCacheFlusher = new MediaCacheFlusher();
nsCOMPtr<nsIObserverService> observerService =
mozilla::services::GetObserverService();
if (observerService) {
observerService->AddObserver(gMediaCacheFlusher, "last-pb-context-exited",
true);
observerService->AddObserver(gMediaCacheFlusher,
"cacheservice:empty-cache", true);
observerService->AddObserver(
gMediaCacheFlusher, "contentchild:network-link-type-changed", true);
observerService->AddObserver(gMediaCacheFlusher,
NS_NETWORK_LINK_TYPE_TOPIC, true);
}
}
gMediaCacheFlusher->mMediaCaches.AppendElement(aMediaCache);
}
/* static */
void MediaCacheFlusher::UnregisterMediaCache(MediaCache* aMediaCache) {
NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
gMediaCacheFlusher->mMediaCaches.RemoveElement(aMediaCache);
if (gMediaCacheFlusher->mMediaCaches.Length() == 0) {
gMediaCacheFlusher = nullptr;
}
}
class MediaCache {
using AutoLock = MonitorAutoLock;
public:
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaCache)
friend class MediaCacheStream::BlockList;
typedef MediaCacheStream::BlockList BlockList;
static const int64_t BLOCK_SIZE = MediaCacheStream::BLOCK_SIZE;
// Get an instance of a MediaCache (or nullptr if initialization failed).
// aContentLength is the content length if known already, otherwise -1.
// If the length is known and considered small enough, a discrete MediaCache
// with memory backing will be given. Otherwise the one MediaCache with
// file backing will be provided.
static RefPtr<MediaCache> GetMediaCache(int64_t aContentLength);
nsIEventTarget* OwnerThread() const { return sThread; }
// Brutally flush the cache contents. Main thread only.
void Flush();
// Close all streams associated with private browsing windows. This will
// also remove the blocks from the cache since we don't want to leave any
// traces when PB is done.
void CloseStreamsForPrivateBrowsing();
// Cache-file access methods. These are the lowest-level cache methods.
// mReentrantMonitor must be held; these can be called on any thread.
// This can return partial reads.
// Note mReentrantMonitor will be dropped while doing IO. The caller need
// to handle changes happening when the monitor is not held.
nsresult ReadCacheFile(AutoLock&, int64_t aOffset, void* aData,
int32_t aLength, int32_t* aBytes);
// The generated IDs are always positive.
int64_t AllocateResourceID(AutoLock&) { return ++mNextResourceID; }
// mReentrantMonitor must be held, called on main thread.
// These methods are used by the stream to set up and tear down streams,
// and to handle reads and writes.
// Add aStream to the list of streams.
void OpenStream(AutoLock&, MediaCacheStream* aStream, bool aIsClone = false);
// Remove aStream from the list of streams.
void ReleaseStream(AutoLock&, MediaCacheStream* aStream);
// Free all blocks belonging to aStream.
void ReleaseStreamBlocks(AutoLock&, MediaCacheStream* aStream);
// Find a cache entry for this data, and write the data into it
void AllocateAndWriteBlock(
AutoLock&, MediaCacheStream* aStream, int32_t aStreamBlockIndex,
MediaCacheStream::ReadMode aMode, Span<const uint8_t> aData1,
Span<const uint8_t> aData2 = Span<const uint8_t>());
// mReentrantMonitor must be held; can be called on any thread
// Notify the cache that a seek has been requested. Some blocks may
// need to change their class between PLAYED_BLOCK and READAHEAD_BLOCK.
// This does not trigger channel seeks directly, the next Update()
// will do that if necessary. The caller will call QueueUpdate().
void NoteSeek(AutoLock&, MediaCacheStream* aStream, int64_t aOldOffset);
// Notify the cache that a block has been read from. This is used
// to update last-use times. The block may not actually have a
// cache entry yet since Read can read data from a stream's
// in-memory mPartialBlockBuffer while the block is only partly full,
// and thus hasn't yet been committed to the cache. The caller will
// call QueueUpdate().
void NoteBlockUsage(AutoLock&, MediaCacheStream* aStream, int32_t aBlockIndex,
int64_t aStreamOffset, MediaCacheStream::ReadMode aMode,
TimeStamp aNow);
// Mark aStream as having the block, adding it as an owner.
void AddBlockOwnerAsReadahead(AutoLock&, int32_t aBlockIndex,
MediaCacheStream* aStream,
int32_t aStreamBlockIndex);
// This queues a call to Update() on the main thread.
void QueueUpdate(AutoLock&);
// Notify all streams for the resource ID that the suspended status changed
// at the end of MediaCache::Update.
void QueueSuspendedStatusUpdate(AutoLock&, int64_t aResourceID);
// Updates the cache state asynchronously on the main thread:
// -- try to trim the cache back to its desired size, if necessary
// -- suspend channels that are going to read data that's lower priority
// than anything currently cached
// -- resume channels that are going to read data that's higher priority
// than something currently cached
// -- seek channels that need to seek to a new location
void Update();
#ifdef DEBUG_VERIFY_CACHE
// Verify invariants, especially block list invariants
void Verify(AutoLock&);
#else
void Verify(AutoLock&) {}
#endif
mozilla::Monitor& Monitor() {
// This method should only be called outside the main thread.
// The MOZ_DIAGNOSTIC_ASSERT(!NS_IsMainThread()) assertion should be
// re-added as part of bug 1464045
return mMonitor;
}
// Polls whether we're on a cellular network connection, and posts a task
// to the MediaCache thread to set the value of MediaCache::sOnCellular.
// Call on main thread only.
static void UpdateOnCellular();
/**
* An iterator that makes it easy to iterate through all streams that
* have a given resource ID and are not closed.
* Must be used while holding the media cache lock.
*/
class ResourceStreamIterator {
public:
ResourceStreamIterator(MediaCache* aMediaCache, int64_t aResourceID)
: mMediaCache(aMediaCache), mResourceID(aResourceID), mNext(0) {
aMediaCache->mMonitor.AssertCurrentThreadOwns();
}
MediaCacheStream* Next(AutoLock& aLock) {
while (mNext < mMediaCache->mStreams.Length()) {
MediaCacheStream* stream = mMediaCache->mStreams[mNext];
++mNext;
if (stream->GetResourceID() == mResourceID && !stream->IsClosed(aLock))
return stream;
}
return nullptr;
}
private:
MediaCache* mMediaCache;
int64_t mResourceID;
uint32_t mNext;
};
protected:
explicit MediaCache(MediaBlockCacheBase* aCache)
: mMonitor("MediaCache.mMonitor"),
mBlockCache(aCache),
mUpdateQueued(false)
#ifdef DEBUG
,
mInUpdate(false)
#endif
{
NS_ASSERTION(NS_IsMainThread(), "Only construct MediaCache on main thread");
MOZ_COUNT_CTOR(MediaCache);
MediaCacheFlusher::RegisterMediaCache(this);
UpdateOnCellular();
}
~MediaCache() {
NS_ASSERTION(NS_IsMainThread(), "Only destroy MediaCache on main thread");
if (this == gMediaCache) {
LOG("~MediaCache(Global file-backed MediaCache)");
// This is the file-backed MediaCache, reset the global pointer.
gMediaCache = nullptr;
// Only gather "MEDIACACHE" telemetry for the file-based cache.
LOG("MediaCache::~MediaCache(this=%p) MEDIACACHE_WATERMARK_KB=%u", this,
unsigned(mIndexWatermark * MediaCache::BLOCK_SIZE / 1024));
Telemetry::Accumulate(
Telemetry::HistogramID::MEDIACACHE_WATERMARK_KB,
uint32_t(mIndexWatermark * MediaCache::BLOCK_SIZE / 1024));
LOG("MediaCache::~MediaCache(this=%p) "
"MEDIACACHE_BLOCKOWNERS_WATERMARK=%u",
this, unsigned(mBlockOwnersWatermark));
Telemetry::Accumulate(
Telemetry::HistogramID::MEDIACACHE_BLOCKOWNERS_WATERMARK,
mBlockOwnersWatermark);
} else {
LOG("~MediaCache(Memory-backed MediaCache %p)", this);
}
MediaCacheFlusher::UnregisterMediaCache(this);
NS_ASSERTION(mStreams.IsEmpty(), "Stream(s) still open!");
Truncate();
NS_ASSERTION(mIndex.Length() == 0, "Blocks leaked?");
MOZ_COUNT_DTOR(MediaCache);
}
static size_t CacheSize() {
MOZ_ASSERT(sThread->IsOnCurrentThread());
return sOnCellular ? StaticPrefs::media_cache_size_cellular()
: StaticPrefs::media_cache_size();
}
static size_t ReadaheadLimit() {
MOZ_ASSERT(sThread->IsOnCurrentThread());
return sOnCellular ? StaticPrefs::media_cache_readahead_limit_cellular()
: StaticPrefs::media_cache_readahead_limit();
}
static size_t ResumeThreshold() {
return sOnCellular ? StaticPrefs::media_cache_resume_threshold_cellular()
: StaticPrefs::media_cache_resume_threshold();
}
// Find a free or reusable block and return its index. If there are no
// free blocks and no reusable blocks, add a new block to the cache
// and return it. Can return -1 on OOM.
int32_t FindBlockForIncomingData(AutoLock&, TimeStamp aNow,
MediaCacheStream* aStream,
int32_t aStreamBlockIndex);
// Find a reusable block --- a free block, if there is one, otherwise
// the reusable block with the latest predicted-next-use, or -1 if
// there aren't any freeable blocks. Only block indices less than
// aMaxSearchBlockIndex are considered. If aForStream is non-null,
// then aForStream and aForStreamBlock indicate what media data will
// be placed; FindReusableBlock will favour returning free blocks
// near other blocks for that point in the stream.
int32_t FindReusableBlock(AutoLock&, TimeStamp aNow,
MediaCacheStream* aForStream,
int32_t aForStreamBlock,
int32_t aMaxSearchBlockIndex);
bool BlockIsReusable(AutoLock&, int32_t aBlockIndex);
// Given a list of blocks sorted with the most reusable blocks at the
// end, find the last block whose stream is not pinned (if any)
// and whose cache entry index is less than aBlockIndexLimit
// and append it to aResult.
void AppendMostReusableBlock(AutoLock&, BlockList* aBlockList,
nsTArray<uint32_t>* aResult,
int32_t aBlockIndexLimit);
enum BlockClass {
// block belongs to mMetadataBlockList because data has been consumed
// from it in "metadata mode" --- in particular blocks read during
// Ogg seeks go into this class. These blocks may have played data
// in them too.
METADATA_BLOCK,
// block belongs to mPlayedBlockList because its offset is
// less than the stream's current reader position
PLAYED_BLOCK,
// block belongs to the stream's mReadaheadBlockList because its
// offset is greater than or equal to the stream's current
// reader position
READAHEAD_BLOCK
};
struct BlockOwner {
constexpr BlockOwner() {}
// The stream that owns this block, or null if the block is free.
MediaCacheStream* mStream = nullptr;
// The block index in the stream. Valid only if mStream is non-null.
// Initialized to an insane value to highlight misuse.
uint32_t mStreamBlock = UINT32_MAX;
// Time at which this block was last used. Valid only if
// mClass is METADATA_BLOCK or PLAYED_BLOCK.
TimeStamp mLastUseTime;
BlockClass mClass = READAHEAD_BLOCK;
};
struct Block {
// Free blocks have an empty mOwners array
nsTArray<BlockOwner> mOwners;
};
// Get the BlockList that the block should belong to given its
// current owner
BlockList* GetListForBlock(AutoLock&, BlockOwner* aBlock);
// Get the BlockOwner for the given block index and owning stream
// (returns null if the stream does not own the block)
BlockOwner* GetBlockOwner(AutoLock&, int32_t aBlockIndex,
MediaCacheStream* aStream);
// Returns true iff the block is free
bool IsBlockFree(int32_t aBlockIndex) {
return mIndex[aBlockIndex].mOwners.IsEmpty();
}
// Add the block to the free list and mark its streams as not having
// the block in cache
void FreeBlock(AutoLock&, int32_t aBlock);
// Mark aStream as not having the block, removing it as an owner. If
// the block has no more owners it's added to the free list.
void RemoveBlockOwner(AutoLock&, int32_t aBlockIndex,
MediaCacheStream* aStream);
// Swap all metadata associated with the two blocks. The caller
// is responsible for swapping up any cache file state.
void SwapBlocks(AutoLock&, int32_t aBlockIndex1, int32_t aBlockIndex2);
// Insert the block into the readahead block list for the stream
// at the right point in the list.
void InsertReadaheadBlock(AutoLock&, BlockOwner* aBlockOwner,
int32_t aBlockIndex);
// Guess the duration until block aBlock will be next used
TimeDuration PredictNextUse(AutoLock&, TimeStamp aNow, int32_t aBlock);
// Guess the duration until the next incoming data on aStream will be used
TimeDuration PredictNextUseForIncomingData(AutoLock&,
MediaCacheStream* aStream);
// Truncate the file and index array if there are free blocks at the
// end
void Truncate();
void FlushInternal(AutoLock&);
// There is at most one file-backed media cache.
// It is owned by all MediaCacheStreams that use it.
// This is a raw pointer set by GetMediaCache(), and reset by ~MediaCache(),
// both on the main thread; and is not accessed anywhere else.
static MediaCache* gMediaCache;
// This member is main-thread only. It's used to allocate unique
// resource IDs to streams.
int64_t mNextResourceID = 0;
// The monitor protects all the data members here. Also, off-main-thread
// readers that need to block will Wait() on this monitor. When new
// data becomes available in the cache, we NotifyAll() on this monitor.
mozilla::Monitor mMonitor;
// This must always be accessed when the monitor is held.
nsTArray<MediaCacheStream*> mStreams;
// The Blocks describing the cache entries.
nsTArray<Block> mIndex;
// Keep track for highest number of blocks used, for telemetry purposes.
int32_t mIndexWatermark = 0;
// Keep track for highest number of blocks owners, for telemetry purposes.
uint32_t mBlockOwnersWatermark = 0;
// Writer which performs IO, asynchronously writing cache blocks.
RefPtr<MediaBlockCacheBase> mBlockCache;
// The list of free blocks; they are not ordered.
BlockList mFreeBlocks;
// True if an event to run Update() has been queued but not processed
bool mUpdateQueued;
#ifdef DEBUG
bool mInUpdate;
#endif
// A list of resource IDs to notify about the change in suspended status.
nsTArray<int64_t> mSuspendedStatusToNotify;
// The thread on which we will run data callbacks from the channels.
// Note this thread is shared among all MediaCache instances.
static StaticRefPtr<nsIThread> sThread;
// True if we've tried to init sThread. Note we try once only so it is safe
// to access sThread on all threads.
static bool sThreadInit;
private:
// MediaCache thread only. True if we're on a cellular network connection.
static bool sOnCellular;
// Used by MediaCacheStream::GetDebugInfo() only for debugging.
// Don't add new callers to this function.
friend void MediaCacheStream::GetDebugInfo(
dom::MediaCacheStreamDebugInfo& aInfo);
mozilla::Monitor& GetMonitorOnTheMainThread() {
MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
return mMonitor;
}
};
// Initialized to nullptr by non-local static initialization.
/* static */
MediaCache* MediaCache::gMediaCache;
/* static */
StaticRefPtr<nsIThread> MediaCache::sThread;
/* static */
bool MediaCache::sThreadInit = false;
/* static */
bool MediaCache::sOnCellular = false;
void MediaCache::UpdateOnCellular() {
NS_ASSERTION(NS_IsMainThread(),
"Only call on main thread"); // JNI required on Android...
bool onCellular = OnCellularConnection();
LOG("MediaCache::UpdateOnCellular() onCellular=%d", onCellular);
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCache::UpdateOnCellular", [=]() { sOnCellular = onCellular; });
sThread->Dispatch(r.forget());
}
NS_IMETHODIMP
MediaCacheFlusher::Observe(nsISupports* aSubject, char const* aTopic,
char16_t const* aData) {
NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
if (strcmp(aTopic, "last-pb-context-exited") == 0) {
for (MediaCache* mc : mMediaCaches) {
mc->CloseStreamsForPrivateBrowsing();
}
return NS_OK;
}
if (strcmp(aTopic, "cacheservice:empty-cache") == 0) {
for (MediaCache* mc : mMediaCaches) {
mc->Flush();
}
return NS_OK;
}
if (strcmp(aTopic, "contentchild:network-link-type-changed") == 0 ||
strcmp(aTopic, NS_NETWORK_LINK_TYPE_TOPIC) == 0) {
MediaCache::UpdateOnCellular();
}
return NS_OK;
}
MediaCacheStream::MediaCacheStream(ChannelMediaResource* aClient,
bool aIsPrivateBrowsing)
: mMediaCache(nullptr),
mClient(aClient),
mIsTransportSeekable(false),
mCacheSuspended(false),
mChannelEnded(false),
mStreamOffset(0),
mPlaybackBytesPerSecond(10000),
mPinCount(0),
mNotifyDataEndedStatus(NS_ERROR_NOT_INITIALIZED),
mMetadataInPartialBlockBuffer(false),
mIsPrivateBrowsing(aIsPrivateBrowsing) {}
size_t MediaCacheStream::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
AutoLock lock(mMediaCache->Monitor());
// Looks like these are not owned:
// - mClient
size_t size = mBlocks.ShallowSizeOfExcludingThis(aMallocSizeOf);
size += mReadaheadBlocks.SizeOfExcludingThis(aMallocSizeOf);
size += mMetadataBlocks.SizeOfExcludingThis(aMallocSizeOf);
size += mPlayedBlocks.SizeOfExcludingThis(aMallocSizeOf);
size += aMallocSizeOf(mPartialBlockBuffer.get());
return size;
}
size_t MediaCacheStream::BlockList::SizeOfExcludingThis(
MallocSizeOf aMallocSizeOf) const {
return mEntries.ShallowSizeOfExcludingThis(aMallocSizeOf);
}
void MediaCacheStream::BlockList::AddFirstBlock(int32_t aBlock) {
NS_ASSERTION(!mEntries.GetEntry(aBlock), "Block already in list");
Entry* entry = mEntries.PutEntry(aBlock);
if (mFirstBlock < 0) {
entry->mNextBlock = entry->mPrevBlock = aBlock;
} else {
entry->mNextBlock = mFirstBlock;
entry->mPrevBlock = mEntries.GetEntry(mFirstBlock)->mPrevBlock;
mEntries.GetEntry(entry->mNextBlock)->mPrevBlock = aBlock;
mEntries.GetEntry(entry->mPrevBlock)->mNextBlock = aBlock;
}
mFirstBlock = aBlock;
++mCount;
}
void MediaCacheStream::BlockList::AddAfter(int32_t aBlock, int32_t aBefore) {
NS_ASSERTION(!mEntries.GetEntry(aBlock), "Block already in list");
Entry* entry = mEntries.PutEntry(aBlock);
Entry* addAfter = mEntries.GetEntry(aBefore);
NS_ASSERTION(addAfter, "aBefore not in list");
entry->mNextBlock = addAfter->mNextBlock;
entry->mPrevBlock = aBefore;
mEntries.GetEntry(entry->mNextBlock)->mPrevBlock = aBlock;
mEntries.GetEntry(entry->mPrevBlock)->mNextBlock = aBlock;
++mCount;
}
void MediaCacheStream::BlockList::RemoveBlock(int32_t aBlock) {
Entry* entry = mEntries.GetEntry(aBlock);
MOZ_DIAGNOSTIC_ASSERT(entry, "Block not in list");
if (entry->mNextBlock == aBlock) {
MOZ_DIAGNOSTIC_ASSERT(entry->mPrevBlock == aBlock,
"Linked list inconsistency");
MOZ_DIAGNOSTIC_ASSERT(mFirstBlock == aBlock, "Linked list inconsistency");
mFirstBlock = -1;
} else {
if (mFirstBlock == aBlock) {
mFirstBlock = entry->mNextBlock;
}
mEntries.GetEntry(entry->mNextBlock)->mPrevBlock = entry->mPrevBlock;
mEntries.GetEntry(entry->mPrevBlock)->mNextBlock = entry->mNextBlock;
}
mEntries.RemoveEntry(entry);
--mCount;
}
int32_t MediaCacheStream::BlockList::GetLastBlock() const {
if (mFirstBlock < 0) return -1;
return mEntries.GetEntry(mFirstBlock)->mPrevBlock;
}
int32_t MediaCacheStream::BlockList::GetNextBlock(int32_t aBlock) const {
int32_t block = mEntries.GetEntry(aBlock)->mNextBlock;
if (block == mFirstBlock) return -1;
return block;
}
int32_t MediaCacheStream::BlockList::GetPrevBlock(int32_t aBlock) const {
if (aBlock == mFirstBlock) return -1;
return mEntries.GetEntry(aBlock)->mPrevBlock;
}
#ifdef DEBUG
void MediaCacheStream::BlockList::Verify() {
int32_t count = 0;
if (mFirstBlock >= 0) {
int32_t block = mFirstBlock;
do {
Entry* entry = mEntries.GetEntry(block);
NS_ASSERTION(mEntries.GetEntry(entry->mNextBlock)->mPrevBlock == block,
"Bad prev link");
NS_ASSERTION(mEntries.GetEntry(entry->mPrevBlock)->mNextBlock == block,
"Bad next link");
block = entry->mNextBlock;
++count;
} while (block != mFirstBlock);
}
NS_ASSERTION(count == mCount, "Bad count");
}
#endif
static void UpdateSwappedBlockIndex(int32_t* aBlockIndex, int32_t aBlock1Index,
int32_t aBlock2Index) {
int32_t index = *aBlockIndex;
if (index == aBlock1Index) {
*aBlockIndex = aBlock2Index;
} else if (index == aBlock2Index) {
*aBlockIndex = aBlock1Index;
}
}
void MediaCacheStream::BlockList::NotifyBlockSwapped(int32_t aBlockIndex1,
int32_t aBlockIndex2) {
Entry* e1 = mEntries.GetEntry(aBlockIndex1);
Entry* e2 = mEntries.GetEntry(aBlockIndex2);
int32_t e1Prev = -1, e1Next = -1, e2Prev = -1, e2Next = -1;
// Fix mFirstBlock
UpdateSwappedBlockIndex(&mFirstBlock, aBlockIndex1, aBlockIndex2);
// Fix mNextBlock/mPrevBlock links. First capture previous/next links
// so we don't get confused due to aliasing.
if (e1) {
e1Prev = e1->mPrevBlock;
e1Next = e1->mNextBlock;
}
if (e2) {
e2Prev = e2->mPrevBlock;
e2Next = e2->mNextBlock;
}
// Update the entries.
if (e1) {
mEntries.GetEntry(e1Prev)->mNextBlock = aBlockIndex2;
mEntries.GetEntry(e1Next)->mPrevBlock = aBlockIndex2;
}
if (e2) {
mEntries.GetEntry(e2Prev)->mNextBlock = aBlockIndex1;
mEntries.GetEntry(e2Next)->mPrevBlock = aBlockIndex1;
}
// Fix hashtable keys. First remove stale entries.
if (e1) {
e1Prev = e1->mPrevBlock;
e1Next = e1->mNextBlock;
mEntries.RemoveEntry(e1);
// Refresh pointer after hashtable mutation.
e2 = mEntries.GetEntry(aBlockIndex2);
}
if (e2) {
e2Prev = e2->mPrevBlock;
e2Next = e2->mNextBlock;
mEntries.RemoveEntry(e2);
}
// Put new entries back.
if (e1) {
e1 = mEntries.PutEntry(aBlockIndex2);
e1->mNextBlock = e1Next;
e1->mPrevBlock = e1Prev;
}
if (e2) {
e2 = mEntries.PutEntry(aBlockIndex1);
e2->mNextBlock = e2Next;
e2->mPrevBlock = e2Prev;
}
}
void MediaCache::FlushInternal(AutoLock& aLock) {
for (uint32_t blockIndex = 0; blockIndex < mIndex.Length(); ++blockIndex) {
FreeBlock(aLock, blockIndex);
}
// Truncate index array.
Truncate();
NS_ASSERTION(mIndex.Length() == 0, "Blocks leaked?");
// Reset block cache to its pristine state.
mBlockCache->Flush();
}
void MediaCache::Flush() {
MOZ_ASSERT(NS_IsMainThread());
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCache::Flush", [self = RefPtr<MediaCache>(this)]() {
AutoLock lock(self->mMonitor);
self->FlushInternal(lock);
});
sThread->Dispatch(r.forget());
}
void MediaCache::CloseStreamsForPrivateBrowsing() {
MOZ_ASSERT(NS_IsMainThread());
sThread->Dispatch(NS_NewRunnableFunction(
"MediaCache::CloseStreamsForPrivateBrowsing",
[self = RefPtr<MediaCache>(this)]() {
AutoLock lock(self->mMonitor);
// Copy mStreams since CloseInternal() will change the array.
nsTArray<MediaCacheStream*> streams(self->mStreams);
for (MediaCacheStream* s : streams) {
if (s->mIsPrivateBrowsing) {
s->CloseInternal(lock);
}
}
}));
}
/* static */
RefPtr<MediaCache> MediaCache::GetMediaCache(int64_t aContentLength) {
NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
if (!sThreadInit) {
sThreadInit = true;
nsCOMPtr<nsIThread> thread;
nsresult rv = NS_NewNamedThread("MediaCache", getter_AddRefs(thread));
if (NS_FAILED(rv)) {
NS_WARNING("Failed to create a thread for MediaCache.");
return nullptr;
}
sThread = thread.forget();
static struct ClearThread {
// Called during shutdown to clear sThread.
void operator=(std::nullptr_t) {
nsCOMPtr<nsIThread> thread = sThread.forget();
MOZ_ASSERT(thread);
thread->Shutdown();
}
} sClearThread;
ClearOnShutdown(&sClearThread, ShutdownPhase::ShutdownThreads);
}
if (!sThread) {
return nullptr;
}
if (aContentLength > 0 &&
aContentLength <=
int64_t(StaticPrefs::media_memory_cache_max_size()) * 1024) {
// Small-enough resource, use a new memory-backed MediaCache.
RefPtr<MediaBlockCacheBase> bc = new MemoryBlockCache(aContentLength);
nsresult rv = bc->Init();
if (NS_SUCCEEDED(rv)) {
RefPtr<MediaCache> mc = new MediaCache(bc);
LOG("GetMediaCache(%" PRIi64 ") -> Memory MediaCache %p", aContentLength,
mc.get());
return mc;
}
// MemoryBlockCache initialization failed, clean up and try for a
// file-backed MediaCache below.
}
if (gMediaCache) {
LOG("GetMediaCache(%" PRIi64 ") -> Existing file-backed MediaCache",
aContentLength);
return gMediaCache;
}
RefPtr<MediaBlockCacheBase> bc = new FileBlockCache();
nsresult rv = bc->Init();
if (NS_SUCCEEDED(rv)) {
gMediaCache = new MediaCache(bc);
LOG("GetMediaCache(%" PRIi64 ") -> Created file-backed MediaCache",
aContentLength);
} else {
LOG("GetMediaCache(%" PRIi64 ") -> Failed to create file-backed MediaCache",
aContentLength);
}
return gMediaCache;
}
nsresult MediaCache::ReadCacheFile(AutoLock&, int64_t aOffset, void* aData,
int32_t aLength, int32_t* aBytes) {
if (!mBlockCache) {
return NS_ERROR_FAILURE;
}
return mBlockCache->Read(aOffset, reinterpret_cast<uint8_t*>(aData), aLength,
aBytes);
}
// Allowed range is whatever can be accessed with an int32_t block index.
static bool IsOffsetAllowed(int64_t aOffset) {
return aOffset < (int64_t(INT32_MAX) + 1) * MediaCache::BLOCK_SIZE &&
aOffset >= 0;
}
// Convert 64-bit offset to 32-bit block index.
// Assumes offset range-check was already done.
static int32_t OffsetToBlockIndexUnchecked(int64_t aOffset) {
// Still check for allowed range in debug builds, to catch out-of-range
// issues early during development.
MOZ_ASSERT(IsOffsetAllowed(aOffset));
return int32_t(aOffset / MediaCache::BLOCK_SIZE);
}
// Convert 64-bit offset to 32-bit block index. -1 if out of allowed range.
static int32_t OffsetToBlockIndex(int64_t aOffset) {
return IsOffsetAllowed(aOffset) ? OffsetToBlockIndexUnchecked(aOffset) : -1;
}
// Convert 64-bit offset to 32-bit offset inside a block.
// Will not fail (even if offset is outside allowed range), so there is no
// need to check for errors.
static int32_t OffsetInBlock(int64_t aOffset) {
// Still check for allowed range in debug builds, to catch out-of-range
// issues early during development.
MOZ_ASSERT(IsOffsetAllowed(aOffset));
return int32_t(aOffset % MediaCache::BLOCK_SIZE);
}
int32_t MediaCache::FindBlockForIncomingData(AutoLock& aLock, TimeStamp aNow,
MediaCacheStream* aStream,
int32_t aStreamBlockIndex) {
MOZ_ASSERT(sThread->IsOnCurrentThread());
int32_t blockIndex =
FindReusableBlock(aLock, aNow, aStream, aStreamBlockIndex, INT32_MAX);
if (blockIndex < 0 || !IsBlockFree(blockIndex)) {
// The block returned is already allocated.
// Don't reuse it if a) there's room to expand the cache or
// b) the data we're going to store in the free block is not higher
// priority than the data already stored in the free block.
// The latter can lead us to go over the cache limit a bit.
if ((mIndex.Length() <
uint32_t(mBlockCache->GetMaxBlocks(MediaCache::CacheSize())) ||
blockIndex < 0 ||
PredictNextUseForIncomingData(aLock, aStream) >=
PredictNextUse(aLock, aNow, blockIndex))) {
blockIndex = mIndex.Length();
if (!mIndex.AppendElement()) return -1;
mIndexWatermark = std::max(mIndexWatermark, blockIndex + 1);
mFreeBlocks.AddFirstBlock(blockIndex);
return blockIndex;
}
}
return blockIndex;
}
bool MediaCache::BlockIsReusable(AutoLock&, int32_t aBlockIndex) {
Block* block = &mIndex[aBlockIndex];
for (uint32_t i = 0; i < block->mOwners.Length(); ++i) {
MediaCacheStream* stream = block->mOwners[i].mStream;
if (stream->mPinCount > 0 ||
uint32_t(OffsetToBlockIndex(stream->mStreamOffset)) ==
block->mOwners[i].mStreamBlock) {
return false;
}
}
return true;
}
void MediaCache::AppendMostReusableBlock(AutoLock& aLock, BlockList* aBlockList,
nsTArray<uint32_t>* aResult,
int32_t aBlockIndexLimit) {
int32_t blockIndex = aBlockList->GetLastBlock();
if (blockIndex < 0) return;
do {
// Don't consider blocks for pinned streams, or blocks that are
// beyond the specified limit, or a block that contains a stream's
// current read position (such a block contains both played data
// and readahead data)
if (blockIndex < aBlockIndexLimit && BlockIsReusable(aLock, blockIndex)) {
aResult->AppendElement(blockIndex);
return;
}
blockIndex = aBlockList->GetPrevBlock(blockIndex);
} while (blockIndex >= 0);
}
int32_t MediaCache::FindReusableBlock(AutoLock& aLock, TimeStamp aNow,
MediaCacheStream* aForStream,
int32_t aForStreamBlock,
int32_t aMaxSearchBlockIndex) {
MOZ_ASSERT(sThread->IsOnCurrentThread());
uint32_t length =
std::min(uint32_t(aMaxSearchBlockIndex), uint32_t(mIndex.Length()));
if (aForStream && aForStreamBlock > 0 &&
uint32_t(aForStreamBlock) <= aForStream->mBlocks.Length()) {
int32_t prevCacheBlock = aForStream->mBlocks[aForStreamBlock - 1];
if (prevCacheBlock >= 0) {
uint32_t freeBlockScanEnd =
std::min(length, prevCacheBlock + FREE_BLOCK_SCAN_LIMIT);
for (uint32_t i = prevCacheBlock; i < freeBlockScanEnd; ++i) {
if (IsBlockFree(i)) return i;
}
}
}
if (!mFreeBlocks.IsEmpty()) {
int32_t blockIndex = mFreeBlocks.GetFirstBlock();
do {
if (blockIndex < aMaxSearchBlockIndex) return blockIndex;
blockIndex = mFreeBlocks.GetNextBlock(blockIndex);
} while (blockIndex >= 0);
}
// Build a list of the blocks we should consider for the "latest
// predicted time of next use". We can exploit the fact that the block
// linked lists are ordered by increasing time of next use. This is
// actually the whole point of having the linked lists.
AutoTArray<uint32_t, 8> candidates;
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
MediaCacheStream* stream = mStreams[i];
if (stream->mPinCount > 0) {
// No point in even looking at this stream's blocks
continue;
}
AppendMostReusableBlock(aLock, &stream->mMetadataBlocks, &candidates,
length);
AppendMostReusableBlock(aLock, &stream->mPlayedBlocks, &candidates, length);
// Don't consider readahead blocks in non-seekable streams. If we
// remove the block we won't be able to seek back to read it later.
if (stream->mIsTransportSeekable) {
AppendMostReusableBlock(aLock, &stream->mReadaheadBlocks, &candidates,
length);
}
}
TimeDuration latestUse;
int32_t latestUseBlock = -1;
for (uint32_t i = 0; i < candidates.Length(); ++i) {
TimeDuration nextUse = PredictNextUse(aLock, aNow, candidates[i]);
if (nextUse > latestUse) {
latestUse = nextUse;
latestUseBlock = candidates[i];
}
}
return latestUseBlock;
}
MediaCache::BlockList* MediaCache::GetListForBlock(AutoLock&,
BlockOwner* aBlock) {
switch (aBlock->mClass) {
case METADATA_BLOCK:
NS_ASSERTION(aBlock->mStream, "Metadata block has no stream?");
return &aBlock->mStream->mMetadataBlocks;
case PLAYED_BLOCK:
NS_ASSERTION(aBlock->mStream, "Metadata block has no stream?");
return &aBlock->mStream->mPlayedBlocks;
case READAHEAD_BLOCK:
NS_ASSERTION(aBlock->mStream, "Readahead block has no stream?");
return &aBlock->mStream->mReadaheadBlocks;
default:
NS_ERROR("Invalid block class");
return nullptr;
}
}
MediaCache::BlockOwner* MediaCache::GetBlockOwner(AutoLock&,
int32_t aBlockIndex,
MediaCacheStream* aStream) {
Block* block = &mIndex[aBlockIndex];
for (uint32_t i = 0; i < block->mOwners.Length(); ++i) {
if (block->mOwners[i].mStream == aStream) return &block->mOwners[i];
}
return nullptr;
}
void MediaCache::SwapBlocks(AutoLock& aLock, int32_t aBlockIndex1,
int32_t aBlockIndex2) {
Block* block1 = &mIndex[aBlockIndex1];
Block* block2 = &mIndex[aBlockIndex2];
block1->mOwners.SwapElements(block2->mOwners);
// Now all references to block1 have to be replaced with block2 and
// vice versa.
// First update stream references to blocks via mBlocks.
const Block* blocks[] = {block1, block2};
int32_t blockIndices[] = {aBlockIndex1, aBlockIndex2};
for (int32_t i = 0; i < 2; ++i) {
for (uint32_t j = 0; j < blocks[i]->mOwners.Length(); ++j) {
const BlockOwner* b = &blocks[i]->mOwners[j];
b->mStream->mBlocks[b->mStreamBlock] = blockIndices[i];
}
}
// Now update references to blocks in block lists.
mFreeBlocks.NotifyBlockSwapped(aBlockIndex1, aBlockIndex2);
nsTHashtable<nsPtrHashKey<MediaCacheStream> > visitedStreams;
for (int32_t i = 0; i < 2; ++i) {
for (uint32_t j = 0; j < blocks[i]->mOwners.Length(); ++j) {
MediaCacheStream* stream = blocks[i]->mOwners[j].mStream;
// Make sure that we don't update the same stream twice --- that
// would result in swapping the block references back again!
if (visitedStreams.GetEntry(stream)) continue;
visitedStreams.PutEntry(stream);
stream->mReadaheadBlocks.NotifyBlockSwapped(aBlockIndex1, aBlockIndex2);
stream->mPlayedBlocks.NotifyBlockSwapped(aBlockIndex1, aBlockIndex2);
stream->mMetadataBlocks.NotifyBlockSwapped(aBlockIndex1, aBlockIndex2);
}
}
Verify(aLock);
}
void MediaCache::RemoveBlockOwner(AutoLock& aLock, int32_t aBlockIndex,
MediaCacheStream* aStream) {
Block* block = &mIndex[aBlockIndex];
for (uint32_t i = 0; i < block->mOwners.Length(); ++i) {
BlockOwner* bo = &block->mOwners[i];
if (bo->mStream == aStream) {
GetListForBlock(aLock, bo)->RemoveBlock(aBlockIndex);
bo->mStream->mBlocks[bo->mStreamBlock] = -1;
block->mOwners.RemoveElementAt(i);
if (block->mOwners.IsEmpty()) {
mFreeBlocks.AddFirstBlock(aBlockIndex);
}
return;
}
}
}
void MediaCache::AddBlockOwnerAsReadahead(AutoLock& aLock, int32_t aBlockIndex,
MediaCacheStream* aStream,
int32_t aStreamBlockIndex) {
Block* block = &mIndex[aBlockIndex];
if (block->mOwners.IsEmpty()) {
mFreeBlocks.RemoveBlock(aBlockIndex);
}
BlockOwner* bo = block->mOwners.AppendElement();
mBlockOwnersWatermark =
std::max(mBlockOwnersWatermark, uint32_t(block->mOwners.Length()));
bo->mStream = aStream;
bo->mStreamBlock = aStreamBlockIndex;
aStream->mBlocks[aStreamBlockIndex] = aBlockIndex;
bo->mClass = READAHEAD_BLOCK;
InsertReadaheadBlock(aLock, bo, aBlockIndex);
}
void MediaCache::FreeBlock(AutoLock& aLock, int32_t aBlock) {
Block* block = &mIndex[aBlock];
if (block->mOwners.IsEmpty()) {
// already free
return;
}
LOG("Released block %d", aBlock);
for (uint32_t i = 0; i < block->mOwners.Length(); ++i) {
BlockOwner* bo = &block->mOwners[i];
GetListForBlock(aLock, bo)->RemoveBlock(aBlock);
bo->mStream->mBlocks[bo->mStreamBlock] = -1;
}
block->mOwners.Clear();
mFreeBlocks.AddFirstBlock(aBlock);
Verify(aLock);
}
TimeDuration MediaCache::PredictNextUse(AutoLock&, TimeStamp aNow,
int32_t aBlock) {
MOZ_ASSERT(sThread->IsOnCurrentThread());
NS_ASSERTION(!IsBlockFree(aBlock), "aBlock is free");
Block* block = &mIndex[aBlock];
// Blocks can be belong to multiple streams. The predicted next use
// time is the earliest time predicted by any of the streams.
TimeDuration result;
for (uint32_t i = 0; i < block->mOwners.Length(); ++i) {
BlockOwner* bo = &block->mOwners[i];
TimeDuration prediction;
switch (bo->mClass) {
case METADATA_BLOCK:
// This block should be managed in LRU mode. For metadata we predict
// that the time until the next use is the time since the last use.
prediction = aNow - bo->mLastUseTime;
break;
case PLAYED_BLOCK: {
// This block should be managed in LRU mode, and we should impose
// a "replay delay" to reflect the likelihood of replay happening
NS_ASSERTION(static_cast<int64_t>(bo->mStreamBlock) * BLOCK_SIZE <
bo->mStream->mStreamOffset,
"Played block after the current stream position?");
int64_t bytesBehind =
bo->mStream->mStreamOffset -
static_cast<int64_t>(bo->mStreamBlock) * BLOCK_SIZE;
int64_t millisecondsBehind =
bytesBehind * 1000 / bo->mStream->mPlaybackBytesPerSecond;
prediction = TimeDuration::FromMilliseconds(std::min<int64_t>(
millisecondsBehind * REPLAY_PENALTY_FACTOR, INT32_MAX));
break;
}
case READAHEAD_BLOCK: {
int64_t bytesAhead =
static_cast<int64_t>(bo->mStreamBlock) * BLOCK_SIZE -
bo->mStream->mStreamOffset;
NS_ASSERTION(bytesAhead >= 0,
"Readahead block before the current stream position?");
int64_t millisecondsAhead =
bytesAhead * 1000 / bo->mStream->mPlaybackBytesPerSecond;
prediction = TimeDuration::FromMilliseconds(
std::min<int64_t>(millisecondsAhead, INT32_MAX));
break;
}
default:
NS_ERROR("Invalid class for predicting next use");
return TimeDuration(0);
}
if (i == 0 || prediction < result) {
result = prediction;
}
}
return result;
}
TimeDuration MediaCache::PredictNextUseForIncomingData(
AutoLock&, MediaCacheStream* aStream) {
MOZ_ASSERT(sThread->IsOnCurrentThread());
int64_t bytesAhead = aStream->mChannelOffset - aStream->mStreamOffset;
if (bytesAhead <= -BLOCK_SIZE) {
// Hmm, no idea when data behind us will be used. Guess 24 hours.
return TimeDuration::FromSeconds(24 * 60 * 60);
}
if (bytesAhead <= 0) return TimeDuration(0);
int64_t millisecondsAhead =
bytesAhead * 1000 / aStream->mPlaybackBytesPerSecond;
return TimeDuration::FromMilliseconds(
std::min<int64_t>(millisecondsAhead, INT32_MAX));
}
void MediaCache::Update() {
MOZ_ASSERT(sThread->IsOnCurrentThread());
AutoLock lock(mMonitor);
struct StreamAction {
enum { NONE, SEEK, RESUME, SUSPEND } mTag = NONE;
// Members for 'SEEK' only.
bool mResume = false;
int64_t mSeekTarget = -1;
};
// The action to use for each stream. We store these so we can make
// decisions while holding the cache lock but implement those decisions
// without holding the cache lock, since we need to call out to
// stream, decoder and element code.
AutoTArray<StreamAction, 10> actions;
mUpdateQueued = false;
#ifdef DEBUG
mInUpdate = true;
#endif
int32_t maxBlocks = mBlockCache->GetMaxBlocks(MediaCache::CacheSize());
TimeStamp now = TimeStamp::Now();
int32_t freeBlockCount = mFreeBlocks.GetCount();
TimeDuration latestPredictedUseForOverflow = 0;
if (mIndex.Length() > uint32_t(maxBlocks)) {
// Try to trim back the cache to its desired maximum size. The cache may
// have overflowed simply due to data being received when we have
// no blocks in the main part of the cache that are free or lower
// priority than the new data. The cache can also be overflowing because
// the media.cache_size preference was reduced.
// First, figure out what the least valuable block in the cache overflow
// is. We don't want to replace any blocks in the main part of the
// cache whose expected time of next use is earlier or equal to that.
// If we allow that, we can effectively end up discarding overflowing
// blocks (by moving an overflowing block to the main part of the cache,
// and then overwriting it with another overflowing block), and we try
// to avoid that since it requires HTTP seeks.
// We also use this loop to eliminate overflowing blocks from
// freeBlockCount.
for (int32_t blockIndex = mIndex.Length() - 1; blockIndex >= maxBlocks;
--blockIndex) {
if (IsBlockFree(blockIndex)) {
// Don't count overflowing free blocks in our free block count
--freeBlockCount;
continue;
}
TimeDuration predictedUse = PredictNextUse(lock, now, blockIndex);
latestPredictedUseForOverflow =
std::max(latestPredictedUseForOverflow, predictedUse);
}
} else {
freeBlockCount += maxBlocks - mIndex.Length();
}
// Now try to move overflowing blocks to the main part of the cache.
for (int32_t blockIndex = mIndex.Length() - 1; blockIndex >= maxBlocks;
--blockIndex) {
if (IsBlockFree(blockIndex)) continue;
Block* block = &mIndex[blockIndex];
// Try to relocate the block close to other blocks for the first stream.
// There is no point in trying to make it close to other blocks in
// *all* the streams it might belong to.
int32_t destinationBlockIndex =
FindReusableBlock(lock, now, block->mOwners[0].mStream,
block->mOwners[0].mStreamBlock, maxBlocks);
if (destinationBlockIndex < 0) {
// Nowhere to place this overflow block. We won't be able to
// place any more overflow blocks.
break;
}
// Don't evict |destinationBlockIndex| if it is within [cur, end) otherwise
// a new channel will be opened to download this block again which is bad.
bool inCurrentCachedRange = false;
for (BlockOwner& owner : mIndex[destinationBlockIndex].mOwners) {
MediaCacheStream* stream = owner.mStream;
int64_t end = OffsetToBlockIndexUnchecked(
stream->GetCachedDataEndInternal(lock, stream->mStreamOffset));
int64_t cur = OffsetToBlockIndexUnchecked(stream->mStreamOffset);
if (cur <= owner.mStreamBlock && owner.mStreamBlock < end) {
inCurrentCachedRange = true;
break;
}
}
if (inCurrentCachedRange) {
continue;
}
if (IsBlockFree(destinationBlockIndex) ||
PredictNextUse(lock, now, destinationBlockIndex) >
latestPredictedUseForOverflow) {
// Reuse blocks in the main part of the cache that are less useful than
// the least useful overflow blocks
nsresult rv = mBlockCache->MoveBlock(blockIndex, destinationBlockIndex);
if (NS_SUCCEEDED(rv)) {
// We successfully copied the file data.
LOG("Swapping blocks %d and %d (trimming cache)", blockIndex,
destinationBlockIndex);
// Swapping the block metadata here lets us maintain the
// correct positions in the linked lists
SwapBlocks(lock, blockIndex, destinationBlockIndex);
// Free the overflowing block even if the copy failed.
LOG("Released block %d (trimming cache)", blockIndex);
FreeBlock(lock, blockIndex);
}
} else {
LOG("Could not trim cache block %d (destination %d, "
"predicted next use %f, latest predicted use for overflow %f",
blockIndex, destinationBlockIndex,
PredictNextUse(lock, now, destinationBlockIndex).ToSeconds(),
latestPredictedUseForOverflow.ToSeconds());
}
}
// Try chopping back the array of cache entries and the cache file.
Truncate();
// Count the blocks allocated for readahead of non-seekable streams
// (these blocks can't be freed but we don't want them to monopolize the
// cache)
int32_t nonSeekableReadaheadBlockCount = 0;
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
MediaCacheStream* stream = mStreams[i];
if (!stream->mIsTransportSeekable) {
nonSeekableReadaheadBlockCount += stream->mReadaheadBlocks.GetCount();
}
}
// If freeBlockCount is zero, then compute the latest of
// the predicted next-uses for all blocks
TimeDuration latestNextUse;
if (freeBlockCount == 0) {
int32_t reusableBlock = FindReusableBlock(lock, now, nullptr, 0, maxBlocks);
if (reusableBlock >= 0) {
latestNextUse = PredictNextUse(lock, now, reusableBlock);
}
}
int32_t resumeThreshold = MediaCache::ResumeThreshold();
int32_t readaheadLimit = MediaCache::ReadaheadLimit();
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
actions.AppendElement(StreamAction{});
MediaCacheStream* stream = mStreams[i];
if (stream->mClosed) {
LOG("Stream %p closed", stream);
continue;
}
// We make decisions based on mSeekTarget when there is a pending seek.
// Otherwise we will keep issuing seek requests until mChannelOffset
// is changed by NotifyDataStarted() which is bad.
int64_t channelOffset = stream->mSeekTarget != -1 ? stream->mSeekTarget
: stream->mChannelOffset;
// Figure out where we should be reading from. It's the first
// uncached byte after the current mStreamOffset.
int64_t dataOffset =
stream->GetCachedDataEndInternal(lock, stream->mStreamOffset);
MOZ_ASSERT(dataOffset >= 0);
// Compute where we'd actually seek to to read at readOffset
int64_t desiredOffset = dataOffset;
if (stream->mIsTransportSeekable) {
if (desiredOffset > channelOffset &&
desiredOffset <= channelOffset + SEEK_VS_READ_THRESHOLD) {
// Assume it's more efficient to just keep reading up to the
// desired position instead of trying to seek
desiredOffset = channelOffset;
}
} else {
// We can't seek directly to the desired offset...
if (channelOffset > desiredOffset) {
// Reading forward won't get us anywhere, we need to go backwards.
// Seek back to 0 (the client will reopen the stream) and then
// read forward.
NS_WARNING("Can't seek backwards, so seeking to 0");
desiredOffset = 0;
// Flush cached blocks out, since if this is a live stream
// the cached data may be completely different next time we
// read it. We have to assume that live streams don't
// advertise themselves as being seekable...
ReleaseStreamBlocks(lock, stream);
} else {
// otherwise reading forward is looking good, so just stay where we
// are and don't trigger a channel seek!
desiredOffset = channelOffset;
}
}
// Figure out if we should be reading data now or not. It's amazing
// how complex this is, but each decision is simple enough.
bool enableReading;
if (stream->mStreamLength >= 0 && dataOffset >= stream->mStreamLength) {
// We want data at the end of the stream, where there's nothing to
// read. We don't want to try to read if we're suspended, because that
// might create a new channel and seek unnecessarily (and incorrectly,
// since HTTP doesn't allow seeking to the actual EOF), and we don't want
// to suspend if we're not suspended and already reading at the end of
// the stream, since there just might be more data than the server
// advertised with Content-Length, and we may as well keep reading.
// But we don't want to seek to the end of the stream if we're not
// already there.
LOG("Stream %p at end of stream", stream);
enableReading =
!stream->mCacheSuspended && stream->mStreamLength == channelOffset;
} else if (desiredOffset < stream->mStreamOffset) {
// We're reading to try to catch up to where the current stream
// reader wants to be. Better not stop.
LOG("Stream %p catching up", stream);
enableReading = true;
} else if (desiredOffset < stream->mStreamOffset + BLOCK_SIZE) {
// The stream reader is waiting for us, or nearly so. Better feed it.
LOG("Stream %p feeding reader", stream);
enableReading = true;
} else if (!stream->mIsTransportSeekable &&
nonSeekableReadaheadBlockCount >=
maxBlocks * NONSEEKABLE_READAHEAD_MAX) {
// This stream is not seekable and there are already too many blocks
// being cached for readahead for nonseekable streams (which we can't
// free). So stop reading ahead now.
LOG("Stream %p throttling non-seekable readahead", stream);
enableReading = false;
} else if (mIndex.Length() > uint32_t(maxBlocks)) {
// We're in the process of bringing the cache size back to the
// desired limit, so don't bring in more data yet
LOG("Stream %p throttling to reduce cache size", stream);
enableReading = false;
} else {
TimeDuration predictedNewDataUse =
PredictNextUseForIncomingData(lock, stream);
if (stream->mThrottleReadahead && stream->mCacheSuspended &&
predictedNewDataUse.ToSeconds() > resumeThreshold) {
// Don't need data for a while, so don't bother waking up the stream
LOG("Stream %p avoiding wakeup since more data is not needed", stream);
enableReading = false;
} else if (stream->mThrottleReadahead &&
predictedNewDataUse.ToSeconds() > readaheadLimit) {
// Don't read ahead more than this much
LOG("Stream %p throttling to avoid reading ahead too far", stream);
enableReading = false;
} else if (freeBlockCount > 0) {
// Free blocks in the cache, so keep reading
LOG("Stream %p reading since there are free blocks", stream);
enableReading = true;
} else if (latestNextUse <= TimeDuration(0)) {
// No reusable blocks, so can't read anything
LOG("Stream %p throttling due to no reusable blocks", stream);
enableReading = false;
} else {
// Read ahead if the data we expect to read is more valuable than
// the least valuable block in the main part of the cache
LOG("Stream %p predict next data in %f, current worst block is %f",
stream, predictedNewDataUse.ToSeconds(), latestNextUse.ToSeconds());
enableReading = predictedNewDataUse < latestNextUse;
}
}
if (enableReading) {
for (uint32_t j = 0; j < i; ++j) {
MediaCacheStream* other = mStreams[j];
if (other->mResourceID == stream->mResourceID && !other->mClosed &&
!other->mClientSuspended && !other->mChannelEnded &&
OffsetToBlockIndexUnchecked(other->mSeekTarget != -1
? other->mSeekTarget
: other->mChannelOffset) ==
OffsetToBlockIndexUnchecked(desiredOffset)) {
// This block is already going to be read by the other stream.
// So don't try to read it from this stream as well.
enableReading = false;
LOG("Stream %p waiting on same block (%" PRId32 ") from stream %p",
stream, OffsetToBlockIndexUnchecked(desiredOffset), other);
break;
}
}
}
if (channelOffset != desiredOffset && enableReading) {
// We need to seek now.
NS_ASSERTION(stream->mIsTransportSeekable || desiredOffset == 0,
"Trying to seek in a non-seekable stream!");
// Round seek offset down to the start of the block. This is essential
// because we don't want to think we have part of a block already
// in mPartialBlockBuffer.
stream->mSeekTarget =
OffsetToBlockIndexUnchecked(desiredOffset) * BLOCK_SIZE;
actions[i].mTag = StreamAction::SEEK;
actions[i].mResume = stream->mCacheSuspended;
actions[i].mSeekTarget = stream->mSeekTarget;
} else if (enableReading && stream->mCacheSuspended) {
actions[i].mTag = StreamAction::RESUME;
} else if (!enableReading && !stream->mCacheSuspended) {
actions[i].mTag = StreamAction::SUSPEND;
}
}
#ifdef DEBUG
mInUpdate = false;
#endif
// First, update the mCacheSuspended/mCacheEnded flags so that they're all
// correct when we fire our CacheClient commands below. Those commands can
// rely on these flags being set correctly for all streams.
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
MediaCacheStream* stream = mStreams[i];
switch (actions[i].mTag) {
case StreamAction::SEEK:
stream->mCacheSuspended = false;
stream->mChannelEnded = false;
break;
case StreamAction::RESUME:
stream->mCacheSuspended = false;
break;
case StreamAction::SUSPEND:
stream->mCacheSuspended = true;
break;
default:
break;
}
}
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
MediaCacheStream* stream = mStreams[i];
switch (actions[i].mTag) {
case StreamAction::SEEK:
LOG("Stream %p CacheSeek to %" PRId64 " (resume=%d)", stream,
actions[i].mSeekTarget, actions[i].mResume);
stream->mClient->CacheClientSeek(actions[i].mSeekTarget,
actions[i].mResume);
break;
case StreamAction::RESUME:
LOG("Stream %p Resumed", stream);
stream->mClient->CacheClientResume();
QueueSuspendedStatusUpdate(lock, stream->mResourceID);
break;
case StreamAction::SUSPEND:
LOG("Stream %p Suspended", stream);
stream->mClient->CacheClientSuspend();
QueueSuspendedStatusUpdate(lock, stream->mResourceID);
break;
default:
break;
}
}
// Notify streams about the suspended status changes.
for (uint32_t i = 0; i < mSuspendedStatusToNotify.Length(); ++i) {
MediaCache::ResourceStreamIterator iter(this, mSuspendedStatusToNotify[i]);
while (MediaCacheStream* stream = iter.Next(lock)) {
stream->mClient->CacheClientNotifySuspendedStatusChanged(
stream->AreAllStreamsForResourceSuspended(lock));
}
}
mSuspendedStatusToNotify.Clear();
}
class UpdateEvent : public Runnable {
public:
explicit UpdateEvent(MediaCache* aMediaCache)
: Runnable("MediaCache::UpdateEvent"), mMediaCache(aMediaCache) {}
NS_IMETHOD Run() override {
mMediaCache->Update();
// Ensure MediaCache is deleted on the main thread.
NS_ProxyRelease("UpdateEvent::mMediaCache",
SystemGroup::EventTargetFor(mozilla::TaskCategory::Other),
mMediaCache.forget());
return NS_OK;
}
private:
RefPtr<MediaCache> mMediaCache;
};
void MediaCache::QueueUpdate(AutoLock&) {
// Queuing an update while we're in an update raises a high risk of
// triggering endless events
NS_ASSERTION(!mInUpdate, "Queuing an update while we're in an update");
if (mUpdateQueued) return;
mUpdateQueued = true;
// XXX MediaCache does updates when decoders are still running at
// shutdown and get freed in the final cycle-collector cleanup. So
// don't leak a runnable in that case.
nsCOMPtr<nsIRunnable> event = new UpdateEvent(this);
sThread->Dispatch(event.forget());
}
void MediaCache::QueueSuspendedStatusUpdate(AutoLock&, int64_t aResourceID) {
if (!mSuspendedStatusToNotify.Contains(aResourceID)) {
mSuspendedStatusToNotify.AppendElement(aResourceID);
}
}
#ifdef DEBUG_VERIFY_CACHE
void MediaCache::Verify(AutoLock&) {
mFreeBlocks.Verify();
for (uint32_t i = 0; i < mStreams.Length(); ++i) {
MediaCacheStream* stream = mStreams[i];
stream->mReadaheadBlocks.Verify();
stream->mPlayedBlocks.Verify();
stream->mMetadataBlocks.Verify();
// Verify that the readahead blocks are listed in stream block order
int32_t block = stream->mReadaheadBlocks.GetFirstBlock();
int32_t lastStreamBlock = -1;
while (block >= 0) {
uint32_t j = 0;
while (mIndex[block].mOwners[j].mStream != stream) {
++j;
}
int32_t nextStreamBlock = int32_t(mIndex[block].mOwners[j].mStreamBlock);
NS_ASSERTION(lastStreamBlock < nextStreamBlock,
"Blocks not increasing in readahead stream");
lastStreamBlock = nextStreamBlock;
block = stream->mReadaheadBlocks.GetNextBlock(block);
}
}
}
#endif
void MediaCache::InsertReadaheadBlock(AutoLock& aLock, BlockOwner* aBlockOwner,
int32_t aBlockIndex) {
// Find the last block whose stream block is before aBlockIndex's
// stream block, and insert after it
MediaCacheStream* stream = aBlockOwner->mStream;
int32_t readaheadIndex = stream->mReadaheadBlocks.GetLastBlock();
while (readaheadIndex >= 0) {
BlockOwner* bo = GetBlockOwner(aLock, readaheadIndex, stream);
NS_ASSERTION(bo, "stream must own its blocks");
if (bo->mStreamBlock < aBlockOwner->mStreamBlock) {
stream->mReadaheadBlocks.AddAfter(aBlockIndex, readaheadIndex);
return;
}
NS_ASSERTION(bo->mStreamBlock > aBlockOwner->mStreamBlock,
"Duplicated blocks??");
readaheadIndex = stream->mReadaheadBlocks.GetPrevBlock(readaheadIndex);
}
stream->mReadaheadBlocks.AddFirstBlock(aBlockIndex);
Verify(aLock);
}
void MediaCache::AllocateAndWriteBlock(AutoLock& aLock,
MediaCacheStream* aStream,
int32_t aStreamBlockIndex,
MediaCacheStream::ReadMode aMode,
Span<const uint8_t> aData1,
Span<const uint8_t> aData2) {
MOZ_ASSERT(sThread->IsOnCurrentThread());
// Remove all cached copies of this block
ResourceStreamIterator iter(this, aStream->mResourceID);
while (MediaCacheStream* stream = iter.Next(aLock)) {
while (aStreamBlockIndex >= int32_t(stream->mBlocks.Length())) {
stream->mBlocks.AppendElement(-1);
}
if (stream->mBlocks[aStreamBlockIndex] >= 0) {
// We no longer want to own this block
int32_t globalBlockIndex = stream->mBlocks[aStreamBlockIndex];
LOG("Released block %d from stream %p block %d(%" PRId64 ")",
globalBlockIndex, stream, aStreamBlockIndex,
aStreamBlockIndex * BLOCK_SIZE);
RemoveBlockOwner(aLock, globalBlockIndex, stream);
}
}
// Extend the mBlocks array as necessary
TimeStamp now = TimeStamp::Now();
int32_t blockIndex =
FindBlockForIncomingData(aLock, now, aStream, aStreamBlockIndex);
if (blockIndex >= 0) {
FreeBlock(aLock, blockIndex);
Block* block = &mIndex[blockIndex];
LOG("Allocated block %d to stream %p block %d(%" PRId64 ")", blockIndex,
aStream, aStreamBlockIndex, aStreamBlockIndex * BLOCK_SIZE);
ResourceStreamIterator iter(this, aStream->mResourceID);
while (MediaCacheStream* stream = iter.Next(aLock)) {
BlockOwner* bo = block->mOwners.AppendElement();
if (!bo) {
// Roll back mOwners if any allocation fails.
block->mOwners.Clear();
return;
}
mBlockOwnersWatermark =
std::max(mBlockOwnersWatermark, uint32_t(block->mOwners.Length()));
bo->mStream = stream;
}
if (block->mOwners.IsEmpty()) {
// This happens when all streams with the resource id are closed. We can
// just return here now and discard the data.
return;
}
// Tell each stream using this resource about the new block.
for (auto& bo : block->mOwners) {
bo.mStreamBlock = aStreamBlockIndex;
bo.mLastUseTime = now;
bo.mStream->mBlocks[aStreamBlockIndex] = blockIndex;
if (aStreamBlockIndex * BLOCK_SIZE < bo.mStream->mStreamOffset) {
bo.mClass = aMode == MediaCacheStream::MODE_PLAYBACK ? PLAYED_BLOCK
: METADATA_BLOCK;
// This must be the most-recently-used block, since we
// marked it as used now (which may be slightly bogus, but we'll
// treat it as used for simplicity).
GetListForBlock(aLock, &bo)->AddFirstBlock(blockIndex);
Verify(aLock);
} else {
// This may not be the latest readahead block, although it usually
// will be. We may have to scan for the right place to insert
// the block in the list.
bo.mClass = READAHEAD_BLOCK;
InsertReadaheadBlock(aLock, &bo, blockIndex);
}
}
// Invariant: block->mOwners.IsEmpty() iff we can find an entry
// in mFreeBlocks for a given blockIndex.
MOZ_DIAGNOSTIC_ASSERT(!block->mOwners.IsEmpty());
mFreeBlocks.RemoveBlock(blockIndex);
nsresult rv = mBlockCache->WriteBlock(blockIndex, aData1, aData2);
if (NS_FAILED(rv)) {
LOG("Released block %d from stream %p block %d(%" PRId64 ")", blockIndex,
aStream, aStreamBlockIndex, aStreamBlockIndex * BLOCK_SIZE);
FreeBlock(aLock, blockIndex);
}
}
// Queue an Update since the cache state has changed (for example
// we might want to stop loading because the cache is full)
QueueUpdate(aLock);
}
void MediaCache::OpenStream(AutoLock& aLock, MediaCacheStream* aStream,
bool aIsClone) {
LOG("Stream %p opened", aStream);
mStreams.AppendElement(aStream);
// A cloned stream should've got the ID from its original.
if (!aIsClone) {
MOZ_ASSERT(aStream->mResourceID == 0, "mResourceID has been initialized.");
aStream->mResourceID = AllocateResourceID(aLock);
}
// We should have a valid ID now no matter it is cloned or not.
MOZ_ASSERT(aStream->mResourceID > 0, "mResourceID is invalid");
// Queue an update since a new stream has been opened.
QueueUpdate(aLock);
}
void MediaCache::ReleaseStream(AutoLock&, MediaCacheStream* aStream) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
LOG("Stream %p closed", aStream);
mStreams.RemoveElement(aStream);
// The caller needs to call QueueUpdate() to re-run Update().
}
void MediaCache::ReleaseStreamBlocks(AutoLock& aLock,
MediaCacheStream* aStream) {
// XXX scanning the entire stream doesn't seem great, if not much of it
// is cached, but the only easy alternative is to scan the entire cache
// which isn't better
uint32_t length = aStream->mBlocks.Length();
for (uint32_t i = 0; i < length; ++i) {
int32_t blockIndex = aStream->mBlocks[i];
if (blockIndex >= 0) {
LOG("Released block %d from stream %p block %d(%" PRId64 ")", blockIndex,
aStream, i, i * BLOCK_SIZE);
RemoveBlockOwner(aLock, blockIndex, aStream);
}
}
}
void MediaCache::Truncate() {
uint32_t end;
for (end = mIndex.Length(); end > 0; --end) {
if (!IsBlockFree(end - 1)) break;
mFreeBlocks.RemoveBlock(end - 1);
}
if (end < mIndex.Length()) {
mIndex.TruncateLength(end);
// XXX We could truncate the cache file here, but we don't seem
// to have a cross-platform API for doing that. At least when all
// streams are closed we shut down the cache, which erases the
// file at that point.
}
}
void MediaCache::NoteBlockUsage(AutoLock& aLock, MediaCacheStream* aStream,
int32_t aBlockIndex, int64_t aStreamOffset,
MediaCacheStream::ReadMode aMode,
TimeStamp aNow) {
if (aBlockIndex < 0) {
// this block is not in the cache yet
return;
}
BlockOwner* bo = GetBlockOwner(aLock, aBlockIndex, aStream);
if (!bo) {
// this block is not in the cache yet
return;
}
// The following check has to be <= because the stream offset has
// not yet been updated for the data read from this block
NS_ASSERTION(bo->mStreamBlock * BLOCK_SIZE <= aStreamOffset,
"Using a block that's behind the read position?");
GetListForBlock(aLock, bo)->RemoveBlock(aBlockIndex);
bo->mClass =
(aMode == MediaCacheStream::MODE_METADATA || bo->mClass == METADATA_BLOCK)
? METADATA_BLOCK
: PLAYED_BLOCK;
// Since this is just being used now, it can definitely be at the front
// of mMetadataBlocks or mPlayedBlocks
GetListForBlock(aLock, bo)->AddFirstBlock(aBlockIndex);
bo->mLastUseTime = aNow;
Verify(aLock);
}
void MediaCache::NoteSeek(AutoLock& aLock, MediaCacheStream* aStream,
int64_t aOldOffset) {
if (aOldOffset < aStream->mStreamOffset) {
// We seeked forward. Convert blocks from readahead to played.
// Any readahead block that intersects the seeked-over range must
// be converted.
int32_t blockIndex = OffsetToBlockIndex(aOldOffset);
if (blockIndex < 0) {
return;
}
int32_t endIndex =
std::min(OffsetToBlockIndex(aStream->mStreamOffset + (BLOCK_SIZE - 1)),
int32_t(aStream->mBlocks.Length()));
if (endIndex < 0) {
return;
}
TimeStamp now = TimeStamp::Now();
while (blockIndex < endIndex) {
int32_t cacheBlockIndex = aStream->mBlocks[blockIndex];
if (cacheBlockIndex >= 0) {
// Marking the block used may not be exactly what we want but
// it's simple
NoteBlockUsage(aLock, aStream, cacheBlockIndex, aStream->mStreamOffset,
MediaCacheStream::MODE_PLAYBACK, now);
}
++blockIndex;
}
} else {
// We seeked backward. Convert from played to readahead.
// Any played block that is entirely after the start of the seeked-over
// range must be converted.
int32_t blockIndex =
OffsetToBlockIndex(aStream->mStreamOffset + (BLOCK_SIZE - 1));
if (blockIndex < 0) {
return;
}
int32_t endIndex =
std::min(OffsetToBlockIndex(aOldOffset + (BLOCK_SIZE - 1)),
int32_t(aStream->mBlocks.Length()));
if (endIndex < 0) {
return;
}
while (blockIndex < endIndex) {
MOZ_ASSERT(endIndex > 0);
int32_t cacheBlockIndex = aStream->mBlocks[endIndex - 1];
if (cacheBlockIndex >= 0) {
BlockOwner* bo = GetBlockOwner(aLock, cacheBlockIndex, aStream);
NS_ASSERTION(bo, "Stream doesn't own its blocks?");
if (bo->mClass == PLAYED_BLOCK) {
aStream->mPlayedBlocks.RemoveBlock(cacheBlockIndex);
bo->mClass = READAHEAD_BLOCK;
// Adding this as the first block is sure to be OK since
// this must currently be the earliest readahead block
// (that's why we're proceeding backwards from the end of
// the seeked range to the start)
aStream->mReadaheadBlocks.AddFirstBlock(cacheBlockIndex);
Verify(aLock);
}
}
--endIndex;
}
}
}
void MediaCacheStream::NotifyLoadID(uint32_t aLoadID) {
MOZ_ASSERT(aLoadID > 0);
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::NotifyLoadID",
[client = RefPtr<ChannelMediaResource>(mClient), this, aLoadID]() {
AutoLock lock(mMediaCache->Monitor());
mLoadID = aLoadID;
});
OwnerThread()->Dispatch(r.forget());
}
void MediaCacheStream::NotifyDataStartedInternal(uint32_t aLoadID,
int64_t aOffset,
bool aSeekable,
int64_t aLength) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
MOZ_ASSERT(aLoadID > 0);
LOG("Stream %p DataStarted: %" PRId64 " aLoadID=%u aLength=%" PRId64, this,
aOffset, aLoadID, aLength);
AutoLock lock(mMediaCache->Monitor());
NS_WARNING_ASSERTION(aOffset == mSeekTarget || aOffset == mChannelOffset,
"Server is giving us unexpected offset");
MOZ_ASSERT(aOffset >= 0);
if (aLength >= 0) {
mStreamLength = aLength;
}
mChannelOffset = aOffset;
if (mStreamLength >= 0) {
// If we started reading at a certain offset, then for sure
// the stream is at least that long.
mStreamLength = std::max(mStreamLength, mChannelOffset);
}
mLoadID = aLoadID;
MOZ_ASSERT(aOffset == 0 || aSeekable,
"channel offset must be zero when we become non-seekable");
mIsTransportSeekable = aSeekable;
// Queue an Update since we may change our strategy for dealing
// with this stream
mMediaCache->QueueUpdate(lock);
// Reset mSeekTarget since the seek is completed so MediaCache::Update() will
// make decisions based on mChannelOffset instead of mSeekTarget.
mSeekTarget = -1;
// Reset these flags since a new load has begun.
mChannelEnded = false;
mDidNotifyDataEnded = false;
UpdateDownloadStatistics(lock);
}
void MediaCacheStream::NotifyDataStarted(uint32_t aLoadID, int64_t aOffset,
bool aSeekable, int64_t aLength) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(aLoadID > 0);
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::NotifyDataStarted",
[=, client = RefPtr<ChannelMediaResource>(mClient)]() {
NotifyDataStartedInternal(aLoadID, aOffset, aSeekable, aLength);
});
OwnerThread()->Dispatch(r.forget());
}
void MediaCacheStream::NotifyDataReceived(uint32_t aLoadID, uint32_t aCount,
const uint8_t* aData) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
MOZ_ASSERT(aLoadID > 0);
AutoLock lock(mMediaCache->Monitor());
if (mClosed) {
// Nothing to do if the stream is closed.
return;
}
LOG("Stream %p DataReceived at %" PRId64 " count=%u aLoadID=%u", this,
mChannelOffset, aCount, aLoadID);
if (mLoadID != aLoadID) {
// mChannelOffset is updated to a new position when loading a new channel.
// We should discard the data coming from the old channel so it won't be
// stored to the wrong positoin.
return;
}
mDownloadStatistics.AddBytes(aCount);
// True if we commit any blocks to the cache.
bool cacheUpdated = false;
auto source = MakeSpan<const uint8_t>(aData, aCount);
// We process the data one block (or part of a block) at a time
while (!source.IsEmpty()) {
// The data we've collected so far in the partial block.
auto partial = MakeSpan<const uint8_t>(mPartialBlockBuffer.get(),
OffsetInBlock(mChannelOffset));
if (partial.IsEmpty()) {
// We've just started filling this buffer so now is a good time
// to clear this flag.
mMetadataInPartialBlockBuffer = false;
}
// The number of bytes needed to complete the partial block.
size_t remaining = BLOCK_SIZE - partial.Length();
if (source.Length() >= remaining) {
// We have a whole block now to write it out.
mMediaCache->AllocateAndWriteBlock(
lock, this, OffsetToBlockIndexUnchecked(mChannelOffset),
mMetadataInPartialBlockBuffer ? MODE_METADATA : MODE_PLAYBACK,
partial, source.First(remaining));
source = source.From(remaining);
mChannelOffset += remaining;
cacheUpdated = true;
} else {
// The buffer to be filled in the partial block.
auto buf = MakeSpan<uint8_t>(mPartialBlockBuffer.get() + partial.Length(),
remaining);
memcpy(buf.Elements(), source.Elements(), source.Length());
mChannelOffset += source.Length();
break;
}
}
MediaCache::ResourceStreamIterator iter(mMediaCache, mResourceID);
while (MediaCacheStream* stream = iter.Next(lock)) {
if (stream->mStreamLength >= 0) {
// The stream is at least as long as what we've read
stream->mStreamLength = std::max(stream->mStreamLength, mChannelOffset);
}
stream->mClient->CacheClientNotifyDataReceived();
}
// XXX it would be fairly easy to optimize things a lot more to
// avoid waking up reader threads unnecessarily
if (cacheUpdated) {
// Wake up the reader who is waiting for the committed blocks.
lock.NotifyAll();
}
}
void MediaCacheStream::FlushPartialBlockInternal(AutoLock& aLock,
bool aNotifyAll) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
int32_t blockIndex = OffsetToBlockIndexUnchecked(mChannelOffset);
int32_t blockOffset = OffsetInBlock(mChannelOffset);
if (blockOffset > 0) {
LOG("Stream %p writing partial block: [%d] bytes; "
"mStreamOffset [%" PRId64 "] mChannelOffset[%" PRId64
"] mStreamLength [%" PRId64 "] notifying: [%s]",
this, blockOffset, mStreamOffset, mChannelOffset, mStreamLength,
aNotifyAll ? "yes" : "no");
// Write back the partial block
memset(mPartialBlockBuffer.get() + blockOffset, 0,
BLOCK_SIZE - blockOffset);
auto data = MakeSpan<const uint8_t>(mPartialBlockBuffer.get(), BLOCK_SIZE);
mMediaCache->AllocateAndWriteBlock(
aLock, this, blockIndex,
mMetadataInPartialBlockBuffer ? MODE_METADATA : MODE_PLAYBACK, data);
}
// |mChannelOffset == 0| means download ends with no bytes received.
// We should also wake up those readers who are waiting for data
// that will never come.
if ((blockOffset > 0 || mChannelOffset == 0) && aNotifyAll) {
// Wake up readers who may be waiting for this data
aLock.NotifyAll();
}
}
void MediaCacheStream::UpdateDownloadStatistics(AutoLock&) {
if (mChannelEnded || mClientSuspended) {
mDownloadStatistics.Stop();
} else {
mDownloadStatistics.Start();
}
}
void MediaCacheStream::NotifyDataEndedInternal(uint32_t aLoadID,
nsresult aStatus) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
AutoLock lock(mMediaCache->Monitor());
if (mClosed || aLoadID != mLoadID) {
// Nothing to do if the stream is closed or a new load has begun.
return;
}
// It is prudent to update channel/cache status before calling
// CacheClientNotifyDataEnded() which will read |mChannelEnded|.
mChannelEnded = true;
mMediaCache->QueueUpdate(lock);
UpdateDownloadStatistics(lock);
if (NS_FAILED(aStatus)) {
// Notify the client about this network error.
mDidNotifyDataEnded = true;
mNotifyDataEndedStatus = aStatus;
mClient->CacheClientNotifyDataEnded(aStatus);
// Wake up the readers so they can fail gracefully.
lock.NotifyAll();
return;
}
// Note we don't flush the partial block when download ends abnormally for
// the padding zeros will give wrong data to other streams.
FlushPartialBlockInternal(lock, true);
MediaCache::ResourceStreamIterator iter(mMediaCache, mResourceID);
while (MediaCacheStream* stream = iter.Next(lock)) {
// We read the whole stream, so remember the true length
stream->mStreamLength = mChannelOffset;
if (!stream->mDidNotifyDataEnded) {
stream->mDidNotifyDataEnded = true;
stream->mNotifyDataEndedStatus = aStatus;
stream->mClient->CacheClientNotifyDataEnded(aStatus);
}
}
}
void MediaCacheStream::NotifyDataEnded(uint32_t aLoadID, nsresult aStatus) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(aLoadID > 0);
RefPtr<ChannelMediaResource> client = mClient;
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::NotifyDataEnded", [client, this, aLoadID, aStatus]() {
NotifyDataEndedInternal(aLoadID, aStatus);
});
OwnerThread()->Dispatch(r.forget());
}
void MediaCacheStream::NotifyClientSuspended(bool aSuspended) {
MOZ_ASSERT(NS_IsMainThread());
RefPtr<ChannelMediaResource> client = mClient;
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::NotifyClientSuspended", [client, this, aSuspended]() {
AutoLock lock(mMediaCache->Monitor());
if (!mClosed && mClientSuspended != aSuspended) {
mClientSuspended = aSuspended;
// mClientSuspended changes the decision of reading streams.
mMediaCache->QueueUpdate(lock);
UpdateDownloadStatistics(lock);
if (mClientSuspended) {
// Download is suspended. Wake up the readers that might be able to
// get data from the partial block.
lock.NotifyAll();
}
}
});
OwnerThread()->Dispatch(r.forget());
}
void MediaCacheStream::NotifyResume() {
MOZ_ASSERT(NS_IsMainThread());
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::NotifyResume",
[this, client = RefPtr<ChannelMediaResource>(mClient)]() {
AutoLock lock(mMediaCache->Monitor());
if (mClosed) {
return;
}
// Don't resume download if we are already at the end of the stream for
// seek will fail and be wasted anyway.
int64_t offset = mSeekTarget != -1 ? mSeekTarget : mChannelOffset;
if (mStreamLength < 0 || offset < mStreamLength) {
mClient->CacheClientSeek(offset, false);
// DownloadResumed() will be notified when a new channel is opened.
}
// The channel remains dead. If we want to read some other data in the
// future, CacheClientSeek() will be called to reopen the channel.
});
OwnerThread()->Dispatch(r.forget());
}
MediaCacheStream::~MediaCacheStream() {
MOZ_ASSERT(NS_IsMainThread(), "Only call on main thread");
MOZ_ASSERT(!mPinCount, "Unbalanced Pin");
MOZ_ASSERT(!mMediaCache || mClosed);
uint32_t lengthKb = uint32_t(std::min(
std::max(mStreamLength, int64_t(0)) / 1024, int64_t(UINT32_MAX)));
LOG("MediaCacheStream::~MediaCacheStream(this=%p) "
"MEDIACACHESTREAM_LENGTH_KB=%" PRIu32,
this, lengthKb);
Telemetry::Accumulate(Telemetry::HistogramID::MEDIACACHESTREAM_LENGTH_KB,
lengthKb);
}
bool MediaCacheStream::AreAllStreamsForResourceSuspended(AutoLock& aLock) {
MOZ_ASSERT(!NS_IsMainThread());
MediaCache::ResourceStreamIterator iter(mMediaCache, mResourceID);
// Look for a stream that's able to read the data we need
int64_t dataOffset = -1;
while (MediaCacheStream* stream = iter.Next(aLock)) {
if (stream->mCacheSuspended || stream->mChannelEnded || stream->mClosed) {
continue;
}
if (dataOffset < 0) {
dataOffset = GetCachedDataEndInternal(aLock, mStreamOffset);
}
// Ignore streams that are reading beyond the data we need
if (stream->mChannelOffset > dataOffset) {
continue;
}
return false;
}
return true;
}
void MediaCacheStream::Close() {
MOZ_ASSERT(NS_IsMainThread());
if (!mMediaCache) {
return;
}
OwnerThread()->Dispatch(NS_NewRunnableFunction(
"MediaCacheStream::Close",
[this, client = RefPtr<ChannelMediaResource>(mClient)]() {
AutoLock lock(mMediaCache->Monitor());
CloseInternal(lock);
}));
}
void MediaCacheStream::CloseInternal(AutoLock& aLock) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
if (mClosed) {
return;
}
// Closing a stream will change the return value of
// MediaCacheStream::AreAllStreamsForResourceSuspended as well as
// ChannelMediaResource::IsSuspendedByCache. Let's notify it.
mMediaCache->QueueSuspendedStatusUpdate(aLock, mResourceID);
mClosed = true;
mMediaCache->ReleaseStreamBlocks(aLock, this);
mMediaCache->ReleaseStream(aLock, this);
// Wake up any blocked readers
aLock.NotifyAll();
// Queue an Update since we may have created more free space.
mMediaCache->QueueUpdate(aLock);
}
void MediaCacheStream::Pin() {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
++mPinCount;
// Queue an Update since we may no longer want to read more into the
// cache, if this stream's block have become non-evictable
mMediaCache->QueueUpdate(lock);
}
void MediaCacheStream::Unpin() {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
NS_ASSERTION(mPinCount > 0, "Unbalanced Unpin");
--mPinCount;
// Queue an Update since we may be able to read more into the
// cache, if this stream's block have become evictable
mMediaCache->QueueUpdate(lock);
}
int64_t MediaCacheStream::GetLength() const {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
return mStreamLength;
}
MediaCacheStream::LengthAndOffset MediaCacheStream::GetLengthAndOffset() const {
MOZ_ASSERT(NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
return {mStreamLength, mChannelOffset};
}
int64_t MediaCacheStream::GetNextCachedData(int64_t aOffset) {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
return GetNextCachedDataInternal(lock, aOffset);
}
int64_t MediaCacheStream::GetCachedDataEnd(int64_t aOffset) {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
return GetCachedDataEndInternal(lock, aOffset);
}
bool MediaCacheStream::IsDataCachedToEndOfStream(int64_t aOffset) {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
if (mStreamLength < 0) return false;
return GetCachedDataEndInternal(lock, aOffset) >= mStreamLength;
}
int64_t MediaCacheStream::GetCachedDataEndInternal(AutoLock&, int64_t aOffset) {
int32_t blockIndex = OffsetToBlockIndex(aOffset);
if (blockIndex < 0) {
return aOffset;
}
while (size_t(blockIndex) < mBlocks.Length() && mBlocks[blockIndex] != -1) {
++blockIndex;
}
int64_t result = blockIndex * BLOCK_SIZE;
if (blockIndex == OffsetToBlockIndexUnchecked(mChannelOffset)) {
// The block containing mChannelOffset may be partially read but not
// yet committed to the main cache
result = mChannelOffset;
}
if (mStreamLength >= 0) {
// The last block in the cache may only be partially valid, so limit
// the cached range to the stream length
result = std::min(result, mStreamLength);
}
return std::max(result, aOffset);
}
int64_t MediaCacheStream::GetNextCachedDataInternal(AutoLock&,
int64_t aOffset) {
if (aOffset == mStreamLength) return -1;
int32_t startBlockIndex = OffsetToBlockIndex(aOffset);
if (startBlockIndex < 0) {
return -1;
}
int32_t channelBlockIndex = OffsetToBlockIndexUnchecked(mChannelOffset);
if (startBlockIndex == channelBlockIndex && aOffset < mChannelOffset) {
// The block containing mChannelOffset is partially read, but not
// yet committed to the main cache. aOffset lies in the partially
// read portion, thus it is effectively cached.
return aOffset;
}
if (size_t(startBlockIndex) >= mBlocks.Length()) return -1;
// Is the current block cached?
if (mBlocks[startBlockIndex] != -1) return aOffset;
// Count the number of uncached blocks
bool hasPartialBlock = OffsetInBlock(mChannelOffset) != 0;
int32_t blockIndex = startBlockIndex + 1;
while (true) {
if ((hasPartialBlock && blockIndex == channelBlockIndex) ||
(size_t(blockIndex) < mBlocks.Length() && mBlocks[blockIndex] != -1)) {
// We at the incoming channel block, which has has data in it,
// or are we at a cached block. Return index of block start.
return blockIndex * BLOCK_SIZE;
}
// No more cached blocks?
if (size_t(blockIndex) >= mBlocks.Length()) return -1;
++blockIndex;
}
MOZ_ASSERT_UNREACHABLE("Should return in loop");
return -1;
}
void MediaCacheStream::SetReadMode(ReadMode aMode) {
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::SetReadMode",
[this, client = RefPtr<ChannelMediaResource>(mClient), aMode]() {
AutoLock lock(mMediaCache->Monitor());
if (!mClosed && mCurrentMode != aMode) {
mCurrentMode = aMode;
mMediaCache->QueueUpdate(lock);
}
});
OwnerThread()->Dispatch(r.forget());
}
void MediaCacheStream::SetPlaybackRate(uint32_t aBytesPerSecond) {
MOZ_ASSERT(!NS_IsMainThread());
MOZ_ASSERT(aBytesPerSecond > 0, "Zero playback rate not allowed");
AutoLock lock(mMediaCache->Monitor());
if (!mClosed && mPlaybackBytesPerSecond != aBytesPerSecond) {
mPlaybackBytesPerSecond = aBytesPerSecond;
mMediaCache->QueueUpdate(lock);
}
}
nsresult MediaCacheStream::Seek(AutoLock& aLock, int64_t aOffset) {
MOZ_ASSERT(!NS_IsMainThread());
if (!IsOffsetAllowed(aOffset)) {
return NS_ERROR_ILLEGAL_VALUE;
}
if (mClosed) {
return NS_ERROR_ABORT;
}
int64_t oldOffset = mStreamOffset;
mStreamOffset = aOffset;
LOG("Stream %p Seek to %" PRId64, this, mStreamOffset);
mMediaCache->NoteSeek(aLock, this, oldOffset);
mMediaCache->QueueUpdate(aLock);
return NS_OK;
}
void MediaCacheStream::ThrottleReadahead(bool bThrottle) {
MOZ_ASSERT(NS_IsMainThread());
nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
"MediaCacheStream::ThrottleReadahead",
[client = RefPtr<ChannelMediaResource>(mClient), this, bThrottle]() {
AutoLock lock(mMediaCache->Monitor());
if (!mClosed && mThrottleReadahead != bThrottle) {
LOGI("Stream %p ThrottleReadahead %d", this, bThrottle);
mThrottleReadahead = bThrottle;
mMediaCache->QueueUpdate(lock);
}
});
OwnerThread()->Dispatch(r.forget());
}
uint32_t MediaCacheStream::ReadPartialBlock(AutoLock&, int64_t aOffset,
Span<char> aBuffer) {
MOZ_ASSERT(IsOffsetAllowed(aOffset));
if (OffsetToBlockIndexUnchecked(mChannelOffset) !=
OffsetToBlockIndexUnchecked(aOffset) ||
aOffset >= mChannelOffset) {
// Not in the partial block or no data to read.
return 0;
}
auto source = MakeSpan<const uint8_t>(
mPartialBlockBuffer.get() + OffsetInBlock(aOffset),
OffsetInBlock(mChannelOffset) - OffsetInBlock(aOffset));
// We have |source.Length() <= BLOCK_SIZE < INT32_MAX| to guarantee
// that |bytesToRead| can fit into a uint32_t.
uint32_t bytesToRead = std::min(aBuffer.Length(), source.Length());
memcpy(aBuffer.Elements(), source.Elements(), bytesToRead);
return bytesToRead;
}
Result<uint32_t, nsresult> MediaCacheStream::ReadBlockFromCache(
AutoLock& aLock, int64_t aOffset, Span<char> aBuffer,
bool aNoteBlockUsage) {
MOZ_ASSERT(IsOffsetAllowed(aOffset));
// OffsetToBlockIndexUnchecked() is always non-negative.
uint32_t index = OffsetToBlockIndexUnchecked(aOffset);
int32_t cacheBlock = index < mBlocks.Length() ? mBlocks[index] : -1;
if (cacheBlock < 0 || (mStreamLength >= 0 && aOffset >= mStreamLength)) {
// Not in the cache.
return 0;
}
if (aBuffer.Length() > size_t(BLOCK_SIZE)) {
// Clamp the buffer to avoid overflow below since we will read at most
// BLOCK_SIZE bytes.
aBuffer = aBuffer.First(BLOCK_SIZE);
}
if (mStreamLength >= 0 &&
int64_t(aBuffer.Length()) > mStreamLength - aOffset) {
// Clamp reads to stream's length
aBuffer = aBuffer.First(mStreamLength - aOffset);
}
// |BLOCK_SIZE - OffsetInBlock(aOffset)| <= BLOCK_SIZE
int32_t bytesToRead =
std::min<int32_t>(BLOCK_SIZE - OffsetInBlock(aOffset), aBuffer.Length());
int32_t bytesRead = 0;
nsresult rv = mMediaCache->ReadCacheFile(
aLock, cacheBlock * BLOCK_SIZE + OffsetInBlock(aOffset),
aBuffer.Elements(), bytesToRead, &bytesRead);
// Ensure |cacheBlock * BLOCK_SIZE + OffsetInBlock(aOffset)| won't overflow.
static_assert(INT64_MAX >= BLOCK_SIZE * (uint32_t(INT32_MAX) + 1),
"BLOCK_SIZE too large!");
if (NS_FAILED(rv)) {
nsCString name;
GetErrorName(rv, name);
LOGE("Stream %p ReadCacheFile failed, rv=%s", this, name.Data());
return mozilla::Err(rv);
}
if (aNoteBlockUsage) {
mMediaCache->NoteBlockUsage(aLock, this, cacheBlock, aOffset, mCurrentMode,
TimeStamp::Now());
}
return bytesRead;
}
nsresult MediaCacheStream::Read(AutoLock& aLock, char* aBuffer, uint32_t aCount,
uint32_t* aBytes) {
MOZ_ASSERT(!NS_IsMainThread());
// Cache the offset in case it is changed again when we are waiting for the
// monitor to be notified to avoid reading at the wrong position.
auto streamOffset = mStreamOffset;
// The buffer we are about to fill.
auto buffer = MakeSpan<char>(aBuffer, aCount);
// Read one block (or part of a block) at a time
while (!buffer.IsEmpty()) {
if (mClosed) {
return NS_ERROR_ABORT;
}
if (!IsOffsetAllowed(streamOffset)) {
LOGE("Stream %p invalid offset=%" PRId64, this, streamOffset);
return NS_ERROR_ILLEGAL_VALUE;
}
if (mStreamLength >= 0 && streamOffset >= mStreamLength) {
// Don't try to read beyond the end of the stream
break;
}
Result<uint32_t, nsresult> rv = ReadBlockFromCache(
aLock, streamOffset, buffer, true /* aNoteBlockUsage */);
if (rv.isErr()) {
return rv.unwrapErr();
}
uint32_t bytes = rv.unwrap();
if (bytes > 0) {
// Got data from the cache successfully. Read next block.
streamOffset += bytes;
buffer = buffer.From(bytes);
continue;
}
// See if we can use the data in the partial block of any stream reading
// this resource. Note we use the partial block only when it is completed,
// that is reaching EOS.
bool foundDataInPartialBlock = false;
MediaCache::ResourceStreamIterator iter(mMediaCache, mResourceID);
while (MediaCacheStream* stream = iter.Next(aLock)) {
if (OffsetToBlockIndexUnchecked(stream->mChannelOffset) ==
OffsetToBlockIndexUnchecked(streamOffset) &&
stream->mChannelOffset == stream->mStreamLength) {
uint32_t bytes = stream->ReadPartialBlock(aLock, streamOffset, buffer);
streamOffset += bytes;
buffer = buffer.From(bytes);
foundDataInPartialBlock = true;
break;
}
}
if (foundDataInPartialBlock) {
// Break for we've reached EOS.
break;
}
if (mDidNotifyDataEnded && NS_FAILED(mNotifyDataEndedStatus)) {
// Since download ends abnormally, there is no point in waiting for new
// data to come. We will check the partial block to read as many bytes as
// possible before exiting this function.
bytes = ReadPartialBlock(aLock, streamOffset, buffer);
streamOffset += bytes;
buffer = buffer.From(bytes);
break;
}
if (mStreamOffset != streamOffset) {
// Update mStreamOffset before we drop the lock. We need to run
// Update() again since stream reading strategy might have changed.
mStreamOffset = streamOffset;
mMediaCache->QueueUpdate(aLock);
}
// No data to read, so block
aLock.Wait();
continue;
}
uint32_t count = buffer.Elements() - aBuffer;
*aBytes = count;
if (count == 0) {
return NS_OK;
}
// Some data was read, so queue an update since block priorities may
// have changed
mMediaCache->QueueUpdate(aLock);
LOG("Stream %p Read at %" PRId64 " count=%d", this, streamOffset - count,
count);
mStreamOffset = streamOffset;
return NS_OK;
}
nsresult MediaCacheStream::ReadAt(int64_t aOffset, char* aBuffer,
uint32_t aCount, uint32_t* aBytes) {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
nsresult rv = Seek(lock, aOffset);
if (NS_FAILED(rv)) return rv;
return Read(lock, aBuffer, aCount, aBytes);
}
nsresult MediaCacheStream::ReadFromCache(char* aBuffer, int64_t aOffset,
uint32_t aCount) {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
// The buffer we are about to fill.
auto buffer = MakeSpan<char>(aBuffer, aCount);
// Read one block (or part of a block) at a time
int64_t streamOffset = aOffset;
while (!buffer.IsEmpty()) {
if (mClosed) {
// We need to check |mClosed| in each iteration which might be changed
// after calling |mMediaCache->ReadCacheFile|.
return NS_ERROR_FAILURE;
}
if (!IsOffsetAllowed(streamOffset)) {
LOGE("Stream %p invalid offset=%" PRId64, this, streamOffset);
return NS_ERROR_ILLEGAL_VALUE;
}
Result<uint32_t, nsresult> rv =
ReadBlockFromCache(lock, streamOffset, buffer);
if (rv.isErr()) {
return rv.unwrapErr();
}
uint32_t bytes = rv.unwrap();
if (bytes > 0) {
// Read data from the cache successfully. Let's try next block.
streamOffset += bytes;
buffer = buffer.From(bytes);
continue;
}
// The partial block is our last chance to get data.
bytes = ReadPartialBlock(lock, streamOffset, buffer);
if (bytes < buffer.Length()) {
// Not enough data to read.
return NS_ERROR_FAILURE;
}
// Return for we've got all the requested bytes.
return NS_OK;
}
return NS_OK;
}
nsresult MediaCacheStream::Init(int64_t aContentLength) {
NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
MOZ_ASSERT(!mMediaCache, "Has been initialized.");
if (aContentLength > 0) {
uint32_t length = uint32_t(std::min(aContentLength, int64_t(UINT32_MAX)));
LOG("MediaCacheStream::Init(this=%p) "
"MEDIACACHESTREAM_NOTIFIED_LENGTH=%" PRIu32,
this, length);
Telemetry::Accumulate(
Telemetry::HistogramID::MEDIACACHESTREAM_NOTIFIED_LENGTH, length);
mStreamLength = aContentLength;
}
mMediaCache = MediaCache::GetMediaCache(aContentLength);
if (!mMediaCache) {
return NS_ERROR_FAILURE;
}
OwnerThread()->Dispatch(NS_NewRunnableFunction(
"MediaCacheStream::Init",
[this, res = RefPtr<ChannelMediaResource>(mClient)]() {
AutoLock lock(mMediaCache->Monitor());
mMediaCache->OpenStream(lock, this);
}));
return NS_OK;
}
void MediaCacheStream::InitAsClone(MediaCacheStream* aOriginal) {
MOZ_ASSERT(!mMediaCache, "Has been initialized.");
MOZ_ASSERT(aOriginal->mMediaCache, "Don't clone an uninitialized stream.");
// Use the same MediaCache as our clone.
mMediaCache = aOriginal->mMediaCache;
OwnerThread()->Dispatch(NS_NewRunnableFunction(
"MediaCacheStream::InitAsClone",
[this, aOriginal, r1 = RefPtr<ChannelMediaResource>(mClient),
r2 = RefPtr<ChannelMediaResource>(aOriginal->mClient)]() {
InitAsCloneInternal(aOriginal);
}));
}
void MediaCacheStream::InitAsCloneInternal(MediaCacheStream* aOriginal) {
MOZ_ASSERT(OwnerThread()->IsOnCurrentThread());
AutoLock lock(mMediaCache->Monitor());
// Download data and notify events if necessary. Note the order is important
// in order to mimic the behavior of data being downloaded from the channel.
// Step 1: copy/download data from the original stream.
mResourceID = aOriginal->mResourceID;
mStreamLength = aOriginal->mStreamLength;
mIsTransportSeekable = aOriginal->mIsTransportSeekable;
mDownloadStatistics = aOriginal->mDownloadStatistics;
mDownloadStatistics.Stop();
// Grab cache blocks from aOriginal as readahead blocks for our stream
for (uint32_t i = 0; i < aOriginal->mBlocks.Length(); ++i) {
int32_t cacheBlockIndex = aOriginal->mBlocks[i];
if (cacheBlockIndex < 0) continue;
while (i >= mBlocks.Length()) {
mBlocks.AppendElement(-1);
}
// Every block is a readahead block for the clone because the clone's
// initial stream offset is zero
mMediaCache->AddBlockOwnerAsReadahead(lock, cacheBlockIndex, this, i);
}
// Copy the partial block.
mChannelOffset = aOriginal->mChannelOffset;
memcpy(mPartialBlockBuffer.get(), aOriginal->mPartialBlockBuffer.get(),
BLOCK_SIZE);
// Step 2: notify the client that we have new data so the decoder has a chance
// to compute 'canplaythrough' and buffer ranges.
mClient->CacheClientNotifyDataReceived();
// Step 3: notify download ended if necessary.
if (aOriginal->mDidNotifyDataEnded &&
NS_SUCCEEDED(aOriginal->mNotifyDataEndedStatus)) {
mNotifyDataEndedStatus = aOriginal->mNotifyDataEndedStatus;
mDidNotifyDataEnded = true;
mClient->CacheClientNotifyDataEnded(mNotifyDataEndedStatus);
}
// Step 4: notify download is suspended by the cache.
mClientSuspended = true;
mCacheSuspended = true;
mChannelEnded = true;
mClient->CacheClientSuspend();
// Step 5: add the stream to be managed by the cache.
mMediaCache->OpenStream(lock, this, true /* aIsClone */);
// Wake up the reader which is waiting for the cloned data.
lock.NotifyAll();
}
nsIEventTarget* MediaCacheStream::OwnerThread() const {
return mMediaCache->OwnerThread();
}
nsresult MediaCacheStream::GetCachedRanges(MediaByteRangeSet& aRanges) {
MOZ_ASSERT(!NS_IsMainThread());
// Take the monitor, so that the cached data ranges can't grow while we're
// trying to loop over them.
AutoLock lock(mMediaCache->Monitor());
// We must be pinned while running this, otherwise the cached data ranges may
// shrink while we're trying to loop over them.
NS_ASSERTION(mPinCount > 0, "Must be pinned");
int64_t startOffset = GetNextCachedDataInternal(lock, 0);
while (startOffset >= 0) {
int64_t endOffset = GetCachedDataEndInternal(lock, startOffset);
NS_ASSERTION(startOffset < endOffset,
"Buffered range must end after its start");
// Bytes [startOffset..endOffset] are cached.
aRanges += MediaByteRange(startOffset, endOffset);
startOffset = GetNextCachedDataInternal(lock, endOffset);
NS_ASSERTION(
startOffset == -1 || startOffset > endOffset,
"Must have advanced to start of next range, or hit end of stream");
}
return NS_OK;
}
double MediaCacheStream::GetDownloadRate(bool* aIsReliable) {
MOZ_ASSERT(!NS_IsMainThread());
AutoLock lock(mMediaCache->Monitor());
return mDownloadStatistics.GetRate(aIsReliable);
}
void MediaCacheStream::GetDebugInfo(dom::MediaCacheStreamDebugInfo& aInfo) {
AutoLock lock(mMediaCache->GetMonitorOnTheMainThread());
aInfo.mStreamLength = mStreamLength;
aInfo.mChannelOffset = mChannelOffset;
aInfo.mCacheSuspended = mCacheSuspended;
aInfo.mChannelEnded = mChannelEnded;
aInfo.mLoadID = mLoadID;
}
} // namespace mozilla
// avoid redefined macro in unified build
#undef LOG
#undef LOGI
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