gecko-dev/gfx/layers/ipc/PLayers.ipdl

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=8 et :
 */
/* 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 LayersSurfaces;
include protocol PCompositor;
include protocol PGrallocBuffer;
include protocol PLayer;
include protocol PRenderFrame;

include "gfxipc/ShadowLayerUtils.h";

/**
 * The layers protocol is spoken between thread contexts that manage
 * layer (sub)trees.  The protocol comprises atomically publishing
 * layer subtrees to a "shadow" thread context (which grafts the
 * subtree into its own tree), and atomically updating a published
 * subtree.  ("Atomic" in this sense is wrt painting.)
 */

namespace mozilla {
namespace layers {

// Create a shadow layer for |layer|
struct OpCreateThebesLayer     { PLayer layer; };
struct OpCreateContainerLayer  { PLayer layer; };
struct OpCreateImageLayer      { PLayer layer; };
struct OpCreateColorLayer      { PLayer layer; };
struct OpCreateCanvasLayer     { PLayer layer; };

struct ThebesBuffer {
  SurfaceDescriptor buffer;
  nsIntRect rect;
  nsIntPoint rotation; 
};
union OptionalThebesBuffer { ThebesBuffer; null_t; };

union CanvasSurface {
  SurfaceDescriptor;
  null_t;
};

// Change a layer's attributes
struct CommonLayerAttributes {
  nsIntRegion visibleRegion;
  gfx3DMatrix transform;
  PRUint32 contentFlags;
  float opacity;
  bool useClipRect;
  nsIntRect clipRect;
  bool isFixedPosition;
  gfxPoint fixedPositionAnchor;
  nullable PLayer maskLayer;
};

struct ThebesLayerAttributes {
  nsIntRegion validRegion;
};
struct ContainerLayerAttributes{ FrameMetrics metrics; };
struct ColorLayerAttributes    { gfxRGBA color; };
struct CanvasLayerAttributes   { GraphicsFilterType filter; };
struct ImageLayerAttributes    {
  GraphicsFilterType filter;
  bool forceSingleTile;
};

union SpecificLayerAttributes {
  null_t;
  ThebesLayerAttributes;
  ContainerLayerAttributes;
  ColorLayerAttributes;
  CanvasLayerAttributes;
  ImageLayerAttributes;
};

struct LayerAttributes {
  CommonLayerAttributes common;
  SpecificLayerAttributes specific;
};

struct OpSetLayerAttributes {
  PLayer layer;
  LayerAttributes attrs;
};


// Monkey with the tree structure
struct OpSetRoot      { PLayer root; };
struct OpInsertAfter  { PLayer container; PLayer childLayer; PLayer after; };
struct OpAppendChild  { PLayer container; PLayer childLayer; };
struct OpRemoveChild  { PLayer container; PLayer childLayer; };


// Paint (buffer update)
struct OpPaintThebesBuffer {
  PLayer layer;
  ThebesBuffer newFrontBuffer;
  nsIntRegion updatedRegion;
};

struct OpPaintTiledLayerBuffer {
  PLayer layer;
  // Bug 747811
  // FIXME: We need to support sharing tile across process.
  uintptr_t tiledLayerBuffer;
};

struct OpPaintCanvas  {
  PLayer layer;
  CanvasSurface newFrontBuffer;
  bool needYFlip;
};

struct OpPaintImage  {
  PLayer layer;
  SharedImage newFrontBuffer;
};


// A unit of a changeset; a set of these comprise a changeset
union Edit {
  OpCreateThebesLayer;
  OpCreateContainerLayer;
  OpCreateImageLayer;
  OpCreateColorLayer;
  OpCreateCanvasLayer;

  OpSetLayerAttributes;

  OpSetRoot;
  OpInsertAfter;
  OpAppendChild;
  OpRemoveChild;

  OpPaintThebesBuffer;
  OpPaintTiledLayerBuffer;
  OpPaintCanvas;
  OpPaintImage;
};


// Replies to operations
struct OpBufferSwap   { PLayer layer; CanvasSurface newBackBuffer; };

struct OpImageSwap { PLayer layer; SharedImage newBackImage; };

struct OpThebesBufferSwap {
  PLayer layer;
  OptionalThebesBuffer newBackBuffer;
  nsIntRegion newValidRegion;
  // If the parent took the child's old back buffer and returned its
  // old front buffer, |readOnlyFrontBuffer| may (if non-null) contain
  // the child's old back buffer (parent's new front buffer).  This
  // buffer can be used to read back the newly updated region into the
  // child's new back buffer.  This buffer must be considered
  // read-only, but sadly that's not enforced.
  OptionalThebesBuffer readOnlyFrontBuffer;
  nsIntRegion frontUpdatedRegion;
};

// Unit of a "changeset reply".  This is a weird abstraction, probably
// only to be used for buffer swapping.
union EditReply {
  OpBufferSwap;
  OpThebesBufferSwap;
  OpImageSwap;
};


sync protocol PLayers {
  manager PRenderFrame or PCompositor;
  manages PGrallocBuffer;
  manages PLayer;

parent:
  /**
   * Only the parent side has privileges to allocate the buffer.
   * Allocation may fail (pmem is a scarce resource), and if so null_t
   * is returned.
   */
  sync PGrallocBuffer(gfxIntSize size, gfxContentType content)
    returns (MaybeMagicGrallocBufferHandle handle);
  async PLayer();

  // The isFirstPaint flag can be used to indicate that this is the first update
  // for a particular document.
  sync Update(Edit[] cset, bool isFirstPaint)
    returns (EditReply[] reply);

  // Composite the layer tree to the given surface, and return the surface.
  sync DrawToSurface(SurfaceDescriptor surfaceIn)
    returns (SurfaceDescriptor surfaceOut);

  // We don't need to send a sync transaction if
  // no transaction operate require a swap.
  async UpdateNoSwap(Edit[] cset, bool isFirstPaint);

  async __delete__();
};

} // namespace layers
} // namespace mozilla