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diff --git a/dom/media/MediaSegment.h b/dom/media/MediaSegment.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef MOZILLA_MEDIASEGMENT_H_
+#define MOZILLA_MEDIASEGMENT_H_
+
+#include "PrincipalHandle.h"
+#include "nsTArray.h"
+#ifdef MOZILLA_INTERNAL_API
+# include "mozilla/TimeStamp.h"
+#endif
+#include <algorithm>
+
+namespace mozilla {
+
+/**
+ * Track or graph rate in Hz. Maximum 1 << TRACK_RATE_MAX_BITS Hz. This
+ * maximum avoids overflow in conversions between track rates and conversions
+ * from seconds.
+ */
+typedef int32_t TrackRate;
+const int64_t TRACK_RATE_MAX_BITS = 20;
+const TrackRate TRACK_RATE_MAX = 1 << TRACK_RATE_MAX_BITS;
+
+/**
+ * A number of ticks at a rate determined by some underlying track (e.g., audio
+ * sample rate). We want to make sure that multiplying TrackTicks by a TrackRate
+ * doesn't overflow, so we set its max accordingly.
+ * TrackTime should be used instead when we're working with MediaTrackGraph's
+ * rate, but TrackTicks can be used outside MediaTracks when we have data at a
+ * different rate.
+ */
+typedef int64_t TrackTicks;
+const int64_t TRACK_TICKS_MAX = INT64_MAX >> TRACK_RATE_MAX_BITS;
+
+/**
+ * We represent media times in 64-bit audio frame counts or ticks.
+ * All tracks in a MediaTrackGraph have the same rate.
+ */
+typedef int64_t MediaTime;
+const int64_t MEDIA_TIME_MAX = TRACK_TICKS_MAX;
+
+/**
+ * Media time relative to the start of a MediaTrack.
+ */
+typedef MediaTime TrackTime;
+const TrackTime TRACK_TIME_MAX = MEDIA_TIME_MAX;
+
+/**
+ * Media time relative to the start of the graph timeline.
+ */
+typedef MediaTime GraphTime;
+const GraphTime GRAPH_TIME_MAX = MEDIA_TIME_MAX;
+
+/* Time conversion helper functions */
+inline TrackTicks RateConvertTicksRoundDown(TrackRate aOutRate,
+ TrackRate aInRate,
+ TrackTicks aTicks) {
+ MOZ_ASSERT(0 < aOutRate && aOutRate <= TRACK_RATE_MAX, "Bad out rate");
+ MOZ_ASSERT(0 < aInRate && aInRate <= TRACK_RATE_MAX, "Bad in rate");
+ MOZ_ASSERT(0 <= aTicks && aTicks <= TRACK_TICKS_MAX, "Bad ticks");
+ return (aTicks * aOutRate) / aInRate;
+}
+
+inline TrackTicks RateConvertTicksRoundUp(TrackRate aOutRate, TrackRate aInRate,
+ TrackTicks aTicks) {
+ MOZ_ASSERT(0 < aOutRate && aOutRate <= TRACK_RATE_MAX, "Bad out rate");
+ MOZ_ASSERT(0 < aInRate && aInRate <= TRACK_RATE_MAX, "Bad in rate");
+ MOZ_ASSERT(0 <= aTicks && aTicks <= TRACK_TICKS_MAX, "Bad ticks");
+ return (aTicks * aOutRate + aInRate - 1) / aInRate;
+}
+
+/**
+ * The number of chunks allocated by default for a MediaSegment.
+ * Appending more chunks than this will cause further allocations.
+ *
+ * 16 is an arbitrary number intended to cover the most common cases in the
+ * MediaTrackGraph (1 with silence and 1-2 with data for a realtime track)
+ * with some margin.
+ */
+const size_t DEFAULT_SEGMENT_CAPACITY = 16;
+
+/**
+ * A MediaSegment is a chunk of media data sequential in time. Different
+ * types of data have different subclasses of MediaSegment, all inheriting
+ * from MediaSegmentBase.
+ * All MediaSegment data is timed using TrackTime. The actual tick rate
+ * is defined on a per-track basis. For some track types, this can be
+ * a fixed constant for all tracks of that type (e.g. 1MHz for video).
+ *
+ * Each media segment defines a concept of "null media data" (e.g. silence
+ * for audio or "no video frame" for video), which can be efficiently
+ * represented. This is used for padding.
+ */
+class MediaSegment {
+ public:
+ MediaSegment(const MediaSegment&) = delete;
+ MediaSegment& operator=(const MediaSegment&) = delete;
+
+ MOZ_COUNTED_DTOR_VIRTUAL(MediaSegment)
+
+ enum Type { AUDIO, VIDEO, TYPE_COUNT };
+
+ /**
+ * Gets the total duration of the segment.
+ */
+ TrackTime GetDuration() const { return mDuration; }
+ Type GetType() const { return mType; }
+
+ /**
+ * Gets the last principal id that was appended to this segment.
+ */
+ const PrincipalHandle& GetLastPrincipalHandle() const {
+ return mLastPrincipalHandle;
+ }
+ /**
+ * Called by the MediaTrackGraph as it appends a chunk with a different
+ * principal id than the current one.
+ */
+ void SetLastPrincipalHandle(PrincipalHandle aLastPrincipalHandle) {
+ mLastPrincipalHandle = std::forward<PrincipalHandle>(aLastPrincipalHandle);
+ }
+
+ /**
+ * Returns true if all chunks in this segment are null.
+ */
+ virtual bool IsNull() const = 0;
+
+ /**
+ * Returns true if this segment contains no chunks.
+ */
+ virtual bool IsEmpty() const = 0;
+
+ /**
+ * Create a MediaSegment of the same type.
+ */
+ virtual MediaSegment* CreateEmptyClone() const = 0;
+ /**
+ * Moves contents of aSource to the end of this segment.
+ */
+ virtual void AppendFrom(MediaSegment* aSource) = 0;
+ /**
+ * Append a slice of aSource to this segment.
+ */
+ virtual void AppendSlice(const MediaSegment& aSource, TrackTime aStart,
+ TrackTime aEnd) = 0;
+ /**
+ * Replace all contents up to aDuration with null data.
+ */
+ virtual void ForgetUpTo(TrackTime aDuration) = 0;
+ /**
+ * Forget all data buffered after a given point
+ */
+ virtual void FlushAfter(TrackTime aNewEnd) = 0;
+ /**
+ * Insert aDuration of null data at the start of the segment.
+ */
+ virtual void InsertNullDataAtStart(TrackTime aDuration) = 0;
+ /**
+ * Insert aDuration of null data at the end of the segment.
+ */
+ virtual void AppendNullData(TrackTime aDuration) = 0;
+ /**
+ * Replace contents with disabled (silence/black) data of the same duration
+ */
+ virtual void ReplaceWithDisabled() = 0;
+ /**
+ * Replace contents with null data of the same duration
+ */
+ virtual void ReplaceWithNull() = 0;
+ /**
+ * Remove all contents, setting duration to 0.
+ */
+ virtual void Clear() = 0;
+
+ virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+ return 0;
+ }
+
+ virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ protected:
+ explicit MediaSegment(Type aType)
+ : mDuration(0),
+ mType(aType),
+ mLastPrincipalHandle(PRINCIPAL_HANDLE_NONE) {
+ MOZ_COUNT_CTOR(MediaSegment);
+ }
+
+ MediaSegment(MediaSegment&& aSegment)
+ : mDuration(std::move(aSegment.mDuration)),
+ mType(std::move(aSegment.mType)),
+ mLastPrincipalHandle(std::move(aSegment.mLastPrincipalHandle)) {
+ MOZ_COUNT_CTOR(MediaSegment);
+ }
+
+ TrackTime mDuration; // total of mDurations of all chunks
+ Type mType;
+
+ // The latest principal handle that the MediaTrackGraph has processed for
+ // this segment.
+ PrincipalHandle mLastPrincipalHandle;
+};
+
+/**
+ * C is the implementation class subclassed from MediaSegmentBase.
+ * C must contain a Chunk class.
+ */
+template <class C, class Chunk>
+class MediaSegmentBase : public MediaSegment {
+ public:
+ bool IsNull() const override {
+ for (typename C::ConstChunkIterator iter(*this); !iter.IsEnded();
+ iter.Next()) {
+ if (!iter->IsNull()) {
+ return false;
+ }
+ }
+ return true;
+ }
+ bool IsEmpty() const override { return mChunks.IsEmpty(); }
+ MediaSegment* CreateEmptyClone() const override { return new C(); }
+ void AppendFrom(MediaSegment* aSource) override {
+ NS_ASSERTION(aSource->GetType() == C::StaticType(), "Wrong type");
+ AppendFromInternal(static_cast<C*>(aSource));
+ }
+ void AppendFrom(C* aSource) { AppendFromInternal(aSource); }
+ void AppendSlice(const MediaSegment& aSource, TrackTime aStart,
+ TrackTime aEnd) override {
+ NS_ASSERTION(aSource.GetType() == C::StaticType(), "Wrong type");
+ AppendSliceInternal(static_cast<const C&>(aSource), aStart, aEnd);
+ }
+ void AppendSlice(const C& aOther, TrackTime aStart, TrackTime aEnd) {
+ AppendSliceInternal(aOther, aStart, aEnd);
+ }
+ /**
+ * Replace the first aDuration ticks with null media data, because the data
+ * will not be required again.
+ */
+ void ForgetUpTo(TrackTime aDuration) override {
+ if (mChunks.IsEmpty() || aDuration <= 0) {
+ return;
+ }
+ if (mChunks[0].IsNull()) {
+ TrackTime extraToForget =
+ std::min(aDuration, mDuration) - mChunks[0].GetDuration();
+ if (extraToForget > 0) {
+ RemoveLeading(extraToForget, 1);
+ mChunks[0].mDuration += extraToForget;
+ mDuration += extraToForget;
+ }
+ return;
+ }
+ RemoveLeading(aDuration, 0);
+ mChunks.InsertElementAt(0)->SetNull(aDuration);
+ mDuration += aDuration;
+ }
+ void FlushAfter(TrackTime aNewEnd) override {
+ if (mChunks.IsEmpty()) {
+ return;
+ }
+
+ if (!aNewEnd) {
+ Clear();
+ } else if (mChunks[0].IsNull()) {
+ TrackTime extraToKeep = aNewEnd - mChunks[0].GetDuration();
+ if (extraToKeep < 0) {
+ // reduce the size of the Null, get rid of everthing else
+ mChunks[0].SetNull(aNewEnd);
+ extraToKeep = 0;
+ }
+ RemoveTrailing(extraToKeep, 1);
+ } else {
+ if (aNewEnd > mDuration) {
+ NS_ASSERTION(aNewEnd <= mDuration, "can't add data in FlushAfter");
+ return;
+ }
+ RemoveTrailing(aNewEnd, 0);
+ }
+ mDuration = aNewEnd;
+ }
+ void InsertNullDataAtStart(TrackTime aDuration) override {
+ if (aDuration <= 0) {
+ return;
+ }
+ if (!mChunks.IsEmpty() && mChunks[0].IsNull()) {
+ mChunks[0].mDuration += aDuration;
+ } else {
+ mChunks.InsertElementAt(0)->SetNull(aDuration);
+ }
+ mDuration += aDuration;
+ }
+ void AppendNullData(TrackTime aDuration) override {
+ if (aDuration <= 0) {
+ return;
+ }
+ if (!mChunks.IsEmpty() && mChunks[mChunks.Length() - 1].IsNull()) {
+ mChunks[mChunks.Length() - 1].mDuration += aDuration;
+ } else {
+ mChunks.AppendElement()->SetNull(aDuration);
+ }
+ mDuration += aDuration;
+ }
+ void ReplaceWithDisabled() override {
+ if (GetType() != AUDIO) {
+ MOZ_CRASH("Disabling unknown segment type");
+ }
+ ReplaceWithNull();
+ }
+ void ReplaceWithNull() override {
+ TrackTime duration = GetDuration();
+ Clear();
+ AppendNullData(duration);
+ }
+ void Clear() override {
+ mDuration = 0;
+ mChunks.ClearAndRetainStorage();
+ mChunks.SetCapacity(DEFAULT_SEGMENT_CAPACITY);
+ }
+
+ class ChunkIterator {
+ public:
+ explicit ChunkIterator(MediaSegmentBase<C, Chunk>& aSegment)
+ : mSegment(aSegment), mIndex(0) {}
+ bool IsEnded() { return mIndex >= mSegment.mChunks.Length(); }
+ void Next() { ++mIndex; }
+ Chunk& operator*() { return mSegment.mChunks[mIndex]; }
+ Chunk* operator->() { return &mSegment.mChunks[mIndex]; }
+
+ private:
+ MediaSegmentBase<C, Chunk>& mSegment;
+ uint32_t mIndex;
+ };
+ class ConstChunkIterator {
+ public:
+ explicit ConstChunkIterator(const MediaSegmentBase<C, Chunk>& aSegment)
+ : mSegment(aSegment), mIndex(0) {}
+ bool IsEnded() { return mIndex >= mSegment.mChunks.Length(); }
+ void Next() { ++mIndex; }
+ const Chunk& operator*() { return mSegment.mChunks[mIndex]; }
+ const Chunk* operator->() { return &mSegment.mChunks[mIndex]; }
+
+ private:
+ const MediaSegmentBase<C, Chunk>& mSegment;
+ uint32_t mIndex;
+ };
+
+ void RemoveLeading(TrackTime aDuration) { RemoveLeading(aDuration, 0); }
+
+ size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override {
+ size_t amount = mChunks.ShallowSizeOfExcludingThis(aMallocSizeOf);
+ for (size_t i = 0; i < mChunks.Length(); i++) {
+ amount += mChunks[i].SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+ }
+ return amount;
+ }
+
+ size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override {
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ Chunk* GetLastChunk() {
+ if (mChunks.IsEmpty()) {
+ return nullptr;
+ }
+ return &mChunks[mChunks.Length() - 1];
+ }
+
+ const Chunk* GetLastChunk() const {
+ if (mChunks.IsEmpty()) {
+ return nullptr;
+ }
+ return &mChunks[mChunks.Length() - 1];
+ }
+
+ protected:
+ explicit MediaSegmentBase(Type aType) : MediaSegment(aType), mChunks() {}
+
+ MediaSegmentBase(MediaSegmentBase&& aSegment)
+ : MediaSegment(std::move(aSegment)),
+ mChunks(std::move(aSegment.mChunks)) {
+ MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
+ "Capacity must be retained in self after swap");
+ MOZ_ASSERT(aSegment.mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
+ "Capacity must be retained in other after swap");
+ }
+
+ /**
+ * Appends the contents of aSource to this segment, clearing aSource.
+ */
+ void AppendFromInternal(MediaSegmentBase<C, Chunk>* aSource) {
+ MOZ_ASSERT(aSource->mDuration >= 0);
+ mDuration += aSource->mDuration;
+ aSource->mDuration = 0;
+ size_t offset = 0;
+ if (!mChunks.IsEmpty() && !aSource->mChunks.IsEmpty() &&
+ mChunks[mChunks.Length() - 1].CanCombineWithFollowing(
+ aSource->mChunks[0])) {
+ mChunks[mChunks.Length() - 1].mDuration += aSource->mChunks[0].mDuration;
+ offset = 1;
+ }
+
+ for (; offset < aSource->mChunks.Length(); ++offset) {
+ mChunks.AppendElement(std::move(aSource->mChunks[offset]));
+ }
+
+ aSource->mChunks.ClearAndRetainStorage();
+ MOZ_ASSERT(aSource->mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
+ "Capacity must be retained after appending from aSource");
+ }
+
+ void AppendSliceInternal(const MediaSegmentBase<C, Chunk>& aSource,
+ TrackTime aStart, TrackTime aEnd) {
+ MOZ_ASSERT(aStart <= aEnd, "Endpoints inverted");
+ NS_ASSERTION(aStart >= 0 && aEnd <= aSource.mDuration,
+ "Slice out of range");
+ mDuration += aEnd - aStart;
+ TrackTime offset = 0;
+ for (uint32_t i = 0; i < aSource.mChunks.Length() && offset < aEnd; ++i) {
+ const Chunk& c = aSource.mChunks[i];
+ TrackTime start = std::max(aStart, offset);
+ TrackTime nextOffset = offset + c.GetDuration();
+ TrackTime end = std::min(aEnd, nextOffset);
+ if (start < end) {
+ if (!mChunks.IsEmpty() &&
+ mChunks[mChunks.Length() - 1].CanCombineWithFollowing(c)) {
+ MOZ_ASSERT(start - offset >= 0 && end - offset <= aSource.mDuration,
+ "Slice out of bounds");
+ mChunks[mChunks.Length() - 1].mDuration += end - start;
+ } else {
+ mChunks.AppendElement(c)->SliceTo(start - offset, end - offset);
+ }
+ }
+ offset = nextOffset;
+ }
+ }
+
+ Chunk* AppendChunk(TrackTime aDuration) {
+ MOZ_ASSERT(aDuration >= 0);
+ Chunk* c = mChunks.AppendElement();
+ c->mDuration = aDuration;
+ mDuration += aDuration;
+ return c;
+ }
+
+ void RemoveLeading(TrackTime aDuration, uint32_t aStartIndex) {
+ NS_ASSERTION(aDuration >= 0, "Can't remove negative duration");
+ TrackTime t = aDuration;
+ uint32_t chunksToRemove = 0;
+ for (uint32_t i = aStartIndex; i < mChunks.Length() && t > 0; ++i) {
+ Chunk* c = &mChunks[i];
+ if (c->GetDuration() > t) {
+ c->SliceTo(t, c->GetDuration());
+ t = 0;
+ break;
+ }
+ t -= c->GetDuration();
+ chunksToRemove = i + 1 - aStartIndex;
+ }
+ if (aStartIndex == 0 && chunksToRemove == mChunks.Length()) {
+ mChunks.ClearAndRetainStorage();
+ } else {
+ mChunks.RemoveElementsAt(aStartIndex, chunksToRemove);
+ }
+ mDuration -= aDuration - t;
+
+ MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
+ "Capacity must be retained after removing chunks");
+ }
+
+ void RemoveTrailing(TrackTime aKeep, uint32_t aStartIndex) {
+ NS_ASSERTION(aKeep >= 0, "Can't keep negative duration");
+ TrackTime t = aKeep;
+ uint32_t i;
+ for (i = aStartIndex; i < mChunks.Length() && t; ++i) {
+ Chunk* c = &mChunks[i];
+ if (c->GetDuration() > t) {
+ c->SliceTo(0, t);
+ break;
+ }
+ t -= c->GetDuration();
+ }
+ // At this point `i` is already advanced due to last check in the loop.
+ if (i < mChunks.Length()) {
+ mChunks.RemoveLastElements(mChunks.Length() - i);
+ }
+ MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
+ "Capacity must be retained after removing chunks");
+ // Caller must adjust mDuration
+ }
+
+ AutoTArray<Chunk, DEFAULT_SEGMENT_CAPACITY> mChunks;
+};
+
+} // namespace mozilla
+
+#endif /* MOZILLA_MEDIASEGMENT_H_ */