fune/dom/media/webcodecs/WebCodecsUtils.h

/* -*- 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/. */

#ifndef MOZILLA_DOM_WEBCODECS_WEBCODECSUTILS_H
#define MOZILLA_DOM_WEBCODECS_WEBCODECSUTILS_H

#include "ErrorList.h"
#include "js/TypeDecls.h"
#include "mozilla/Maybe.h"
#include "mozilla/MozPromise.h"
#include "mozilla/Result.h"
#include "mozilla/TaskQueue.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "mozilla/dom/Nullable.h"
#include "mozilla/dom/UnionTypes.h"
#include "mozilla/dom/VideoEncoderBinding.h"
#include "mozilla/dom/VideoFrameBinding.h"
#include "PlatformEncoderModule.h"

namespace mozilla {

namespace gfx {
enum class ColorRange : uint8_t;
enum class ColorSpace2 : uint8_t;
enum class SurfaceFormat : int8_t;
enum class TransferFunction : uint8_t;
enum class YUVColorSpace : uint8_t;
}  // namespace gfx

using WebCodecsId = size_t;

extern std::atomic<WebCodecsId> sNextId;

struct EncoderConfigurationChangeList;

namespace dom {

/*
 * The followings are helpers for WebCodecs methods.
 */

nsTArray<nsCString> GuessContainers(const nsAString& aCodec);

Maybe<nsString> ParseCodecString(const nsAString& aCodec);

/*
 * Below are helpers for conversion among Maybe, Optional, and Nullable.
 */

template <typename T>
Maybe<T> OptionalToMaybe(const Optional<T>& aOptional) {
  if (aOptional.WasPassed()) {
    return Some(aOptional.Value());
  }
  return Nothing();
}

template <typename T>
const T* OptionalToPointer(const Optional<T>& aOptional) {
  return aOptional.WasPassed() ? &aOptional.Value() : nullptr;
}

template <typename T>
Maybe<T> NullableToMaybe(const Nullable<T>& aNullable) {
  if (!aNullable.IsNull()) {
    return Some(aNullable.Value());
  }
  return Nothing();
}

template <typename T>
Nullable<T> MaybeToNullable(const Maybe<T>& aOptional) {
  if (aOptional.isSome()) {
    return Nullable<T>(aOptional.value());
  }
  return Nullable<T>();
}

/*
 * Below are helpers to operate ArrayBuffer or ArrayBufferView.
 */

Result<Ok, nsresult> CloneBuffer(
    JSContext* aCx,
    OwningMaybeSharedArrayBufferViewOrMaybeSharedArrayBuffer& aDest,
    const OwningMaybeSharedArrayBufferViewOrMaybeSharedArrayBuffer& aSrc);

/*
 * The following are utilities to convert between VideoColorSpace values to
 * gfx's values.
 */

enum class VideoColorPrimaries : uint8_t;
enum class VideoMatrixCoefficients : uint8_t;
enum class VideoTransferCharacteristics : uint8_t;

gfx::ColorRange ToColorRange(bool aIsFullRange);

gfx::YUVColorSpace ToColorSpace(VideoMatrixCoefficients aMatrix);

gfx::TransferFunction ToTransferFunction(
    VideoTransferCharacteristics aTransfer);

gfx::ColorSpace2 ToPrimaries(VideoColorPrimaries aPrimaries);

bool ToFullRange(const gfx::ColorRange& aColorRange);

Maybe<VideoMatrixCoefficients> ToMatrixCoefficients(
    const gfx::YUVColorSpace& aColorSpace);

Maybe<VideoTransferCharacteristics> ToTransferCharacteristics(
    const gfx::TransferFunction& aTransferFunction);

Maybe<VideoColorPrimaries> ToPrimaries(const gfx::ColorSpace2& aColorSpace);

/*
 * The following are utilities to convert from gfx's formats to
 * VideoPixelFormats.
 */

enum class ImageBitmapFormat : uint8_t;
enum class VideoPixelFormat : uint8_t;

Maybe<VideoPixelFormat> SurfaceFormatToVideoPixelFormat(
    gfx::SurfaceFormat aFormat);

Maybe<VideoPixelFormat> ImageBitmapFormatToVideoPixelFormat(
    ImageBitmapFormat aFormat);

template <typename T>
class MessageRequestHolder {
 public:
  MessageRequestHolder() = default;
  ~MessageRequestHolder() = default;

  MozPromiseRequestHolder<T>& Request() { return mRequest; }
  void Disconnect() { mRequest.DisconnectIfExists(); }
  void Complete() { mRequest.Complete(); }
  bool Exists() const { return mRequest.Exists(); }

 protected:
  MozPromiseRequestHolder<T> mRequest{};
};

enum class MessageProcessedResult { NotProcessed, Processed };

bool IsOnAndroid();
bool IsOnMacOS();
bool IsOnLinux();

// Wrap a type to make it unique. This allows using ergonomically in the Variant
// below. Simply aliasing with `using` isn't enough, because typedefs in C++
// don't produce strong types, so two integer variants result in
// the same type, making it ambiguous to the Variant code.
// T is the type to be wrapped. Phantom is a type that is only used to
// disambiguate and should be unique in the program.
template <typename T, typename Phantom>
class StrongTypedef {
 public:
  explicit StrongTypedef(T const& value) : mValue(value) {}
  explicit StrongTypedef(T&& value) : mValue(std::move(value)) {}
  T& get() { return mValue; }
  T const& get() const { return mValue; }

 private:
  T mValue;
};

using CodecChange = StrongTypedef<nsString, struct CodecChangeTypeWebCodecs>;
using DimensionsChange =
    StrongTypedef<gfx::IntSize, struct DimensionsChangeTypeWebCodecs>;
using DisplayDimensionsChange =
    StrongTypedef<Maybe<gfx::IntSize>,
                  struct DisplayDimensionsChangeTypeWebCodecs>;
using BitrateChange =
    StrongTypedef<Maybe<uint32_t>, struct BitrateChangeTypeWebCodecs>;
using FramerateChange =
    StrongTypedef<Maybe<double>, struct FramerateChangeTypeWebCodecs>;
using HardwareAccelerationChange =
    StrongTypedef<dom::HardwareAcceleration,
                  struct HardwareAccelerationChangeTypeWebCodecs>;
using AlphaChange =
    StrongTypedef<dom::AlphaOption, struct AlphaChangeTypeWebCodecs>;
using ScalabilityModeChange =
    StrongTypedef<Maybe<nsString>, struct ScalabilityModeChangeTypeWebCodecs>;
using BitrateModeChange = StrongTypedef<dom::VideoEncoderBitrateMode,
                                        struct BitrateModeChangeTypeWebCodecs>;
using LatencyModeChange =
    StrongTypedef<dom::LatencyMode, struct LatencyModeTypeChangeTypeWebCodecs>;
using ContentHintChange =
    StrongTypedef<Maybe<nsString>, struct ContentHintTypeTypeWebCodecs>;

using WebCodecsEncoderConfigurationItem =
    Variant<CodecChange, DimensionsChange, DisplayDimensionsChange,
            BitrateModeChange, BitrateChange, FramerateChange,
            HardwareAccelerationChange, AlphaChange, ScalabilityModeChange,
            LatencyModeChange, ContentHintChange>;

struct WebCodecsConfigurationChangeList {
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WebCodecsConfigurationChangeList)
  bool Empty() const { return mChanges.IsEmpty(); }
  template <typename T>
  void Push(const T& aItem) {
    mChanges.AppendElement(aItem);
  }
  // This returns true if it should be possible to attempt to reconfigure the
  // encoder on the fly. It can fail, in which case the encoder will be flushed
  // and a new one will be created with the new set of parameters.
  bool CanAttemptReconfigure() const;

  // Convert this to the format the underlying PEM can understand
  RefPtr<EncoderConfigurationChangeList> ToPEMChangeList() const;
  nsString ToString() const;

  nsTArray<WebCodecsEncoderConfigurationItem> mChanges;

 private:
  ~WebCodecsConfigurationChangeList() = default;
};

nsCString ColorSpaceInitToString(
    const dom::VideoColorSpaceInit& aColorSpaceInit);

RefPtr<TaskQueue> GetWebCodecsEncoderTaskQueue();
VideoColorSpaceInit FallbackColorSpaceForVideoContent();
VideoColorSpaceInit FallbackColorSpaceForWebContent();

Maybe<CodecType> CodecStringToCodecType(const nsAString& aCodecString);

nsString ConfigToString(const VideoDecoderConfig& aConfig);

}  // namespace dom

}  // namespace mozilla

#endif  // MOZILLA_DOM_WEBCODECS_WEBCODECSUTILS_H