chrome-devtools-frontend/front_end/layers/LayerTreeModel.ts

Chrome DevTools UI

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* eslint-disable rulesdir/no_underscored_properties */

import * as Common from '../common/common.js';
import * as SDK from '../sdk/sdk.js';
import * as UI from '../ui/ui.js';

export class LayerTreeModel extends SDK.SDKModel.SDKModel {
  _layerTreeAgent: ProtocolProxyApi.LayerTreeApi;
  _paintProfilerModel: SDK.PaintProfiler.PaintProfilerModel;
  _layerTree: SDK.LayerTreeBase.LayerTreeBase|null;
  _throttler: Common.Throttler.Throttler;
  _enabled?: boolean;
  _lastPaintRectByLayerId?: Map<string, Protocol.DOM.Rect>;

  constructor(target: SDK.SDKModel.Target) {
    super(target);
    this._layerTreeAgent = target.layerTreeAgent();
    target.registerLayerTreeDispatcher(new LayerTreeDispatcher(this));
    this._paintProfilerModel =
        target.model(SDK.PaintProfiler.PaintProfilerModel) as SDK.PaintProfiler.PaintProfilerModel;
    const resourceTreeModel = target.model(SDK.ResourceTreeModel.ResourceTreeModel);
    if (resourceTreeModel) {
      resourceTreeModel.addEventListener(
          SDK.ResourceTreeModel.Events.MainFrameNavigated, this._onMainFrameNavigated, this);
    }
    this._layerTree = null;
    this._throttler = new Common.Throttler.Throttler(20);
  }

  async disable(): Promise<void> {
    if (!this._enabled) {
      return;
    }
    this._enabled = false;
    await this._layerTreeAgent.invoke_disable();
  }

  enable(): void {
    if (this._enabled) {
      return;
    }
    this._enabled = true;
    this._forceEnable();
  }

  async _forceEnable(): Promise<void> {
    this._lastPaintRectByLayerId = new Map();
    if (!this._layerTree) {
      this._layerTree = new AgentLayerTree(this);
    }
    await this._layerTreeAgent.invoke_enable();
  }

  layerTree(): SDK.LayerTreeBase.LayerTreeBase|null {
    return this._layerTree;
  }

  async _layerTreeChanged(layers: Protocol.LayerTree.Layer[]|null): Promise<void> {
    if (!this._enabled) {
      return;
    }
    this._throttler.schedule(this._innerSetLayers.bind(this, layers));
  }

  async _innerSetLayers(layers: Protocol.LayerTree.Layer[]|null): Promise<void> {
    const layerTree = this._layerTree as AgentLayerTree;

    await layerTree.setLayers(layers);

    if (!this._lastPaintRectByLayerId) {
      this._lastPaintRectByLayerId = new Map();
    }

    for (const layerId of this._lastPaintRectByLayerId.keys()) {
      const lastPaintRect = this._lastPaintRectByLayerId.get(layerId);
      const layer = layerTree.layerById(layerId);
      if (layer) {
        (layer as AgentLayer)._lastPaintRect = lastPaintRect;
      }
    }

    this._lastPaintRectByLayerId = new Map();

    this.dispatchEventToListeners(Events.LayerTreeChanged);
  }

  _layerPainted(layerId: string, clipRect: Protocol.DOM.Rect): void {
    if (!this._enabled) {
      return;
    }
    const layerTree = this._layerTree as AgentLayerTree;
    const layer = layerTree.layerById(layerId) as AgentLayer;
    if (!layer) {
      if (!this._lastPaintRectByLayerId) {
        this._lastPaintRectByLayerId = new Map();
      }

      this._lastPaintRectByLayerId.set(layerId, clipRect);
      return;
    }
    layer._didPaint(clipRect);
    this.dispatchEventToListeners(Events.LayerPainted, layer);
  }

  _onMainFrameNavigated(): void {
    this._layerTree = null;
    if (this._enabled) {
      this._forceEnable();
    }
  }
}

SDK.SDKModel.SDKModel.register(LayerTreeModel, SDK.SDKModel.Capability.DOM, false);

// TODO(crbug.com/1167717): Make this a const enum again
// eslint-disable-next-line rulesdir/const_enum
export enum Events {
  LayerTreeChanged = 'LayerTreeChanged',
  LayerPainted = 'LayerPainted',
}

export class AgentLayerTree extends SDK.LayerTreeBase.LayerTreeBase {
  _layerTreeModel: LayerTreeModel;

  constructor(layerTreeModel: LayerTreeModel) {
    super(layerTreeModel.target());
    this._layerTreeModel = layerTreeModel;
  }

  async setLayers(payload: Protocol.LayerTree.Layer[]|null): Promise<void> {
    if (!payload) {
      this._innerSetLayers(payload);
      return;
    }
    const idsToResolve = new Set<number>();
    for (let i = 0; i < payload.length; ++i) {
      const backendNodeId = payload[i].backendNodeId;
      if (!backendNodeId || this.backendNodeIdToNode().has(backendNodeId)) {
        continue;
      }
      idsToResolve.add(backendNodeId);
    }
    await this.resolveBackendNodeIds(idsToResolve);
    this._innerSetLayers(payload);
  }

  _innerSetLayers(layers: Protocol.LayerTree.Layer[]|null): void {
    this.setRoot(null);
    this.setContentRoot(null);
    // Payload will be null when not in the composited mode.
    if (!layers) {
      return;
    }
    let root;
    const oldLayersById = this.layersById;
    this.layersById = new Map();
    for (let i = 0; i < layers.length; ++i) {
      const layerId = layers[i].layerId;
      let layer: AgentLayer|(AgentLayer | null) = oldLayersById.get(layerId) as AgentLayer | null;
      if (layer) {
        layer._reset(layers[i]);
      } else {
        layer = new AgentLayer(this._layerTreeModel, layers[i]);
      }
      this.layersById.set(layerId, layer);
      const backendNodeId = layers[i].backendNodeId;
      if (backendNodeId) {
        layer._setNode(this.backendNodeIdToNode().get(backendNodeId) || null);
      }
      if (!this.contentRoot() && layer.drawsContent()) {
        this.setContentRoot(layer);
      }
      const parentId = layer.parentId();
      if (parentId) {
        const parent = this.layersById.get(parentId);
        if (!parent) {
          throw new Error(`Missing parent ${parentId} for layer ${layerId}`);
        }
        parent.addChild(layer);
      } else {
        if (root) {
          console.assert(false, 'Multiple root layers');
        }
        root = layer;
      }
    }
    if (root) {
      this.setRoot(root);
      root._calculateQuad(new WebKitCSSMatrix());
    }
  }
}

export class AgentLayer implements SDK.LayerTreeBase.Layer {
  _scrollRects!: Protocol.LayerTree.ScrollRect[];
  _quad!: number[];
  _children!: AgentLayer[];
  _image!: HTMLImageElement|null;
  _parent!: AgentLayer|null;
  _layerPayload!: Protocol.LayerTree.Layer;
  _layerTreeModel: LayerTreeModel;
  _node?: SDK.DOMModel.DOMNode|null;
  _lastPaintRect?: Protocol.DOM.Rect;
  _paintCount?: number;
  _stickyPositionConstraint?: SDK.LayerTreeBase.StickyPositionConstraint|null;
  constructor(layerTreeModel: LayerTreeModel, layerPayload: Protocol.LayerTree.Layer) {
    this._layerTreeModel = layerTreeModel;
    this._reset(layerPayload);
  }

  id(): string {
    return this._layerPayload.layerId;
  }

  parentId(): string|null {
    return this._layerPayload.parentLayerId || null;
  }

  parent(): SDK.LayerTreeBase.Layer|null {
    return this._parent;
  }

  isRoot(): boolean {
    return !this.parentId();
  }

  children(): SDK.LayerTreeBase.Layer[] {
    return this._children;
  }

  addChild(childParam: SDK.LayerTreeBase.Layer): void {
    const child = childParam as AgentLayer;
    if (child._parent) {
      console.assert(false, 'Child already has a parent');
    }
    this._children.push(child);
    child._parent = this;
  }

  _setNode(node: SDK.DOMModel.DOMNode|null): void {
    this._node = node;
  }

  node(): SDK.DOMModel.DOMNode|null {
    return this._node || null;
  }

  nodeForSelfOrAncestor(): SDK.DOMModel.DOMNode|null {
    let layer: (AgentLayer|null)|this = this;
    for (; layer; layer = layer._parent) {
      if (layer._node) {
        return layer._node;
      }
    }
    return null;
  }

  offsetX(): number {
    return this._layerPayload.offsetX;
  }

  offsetY(): number {
    return this._layerPayload.offsetY;
  }

  width(): number {
    return this._layerPayload.width;
  }

  height(): number {
    return this._layerPayload.height;
  }

  transform(): number[]|null {
    return this._layerPayload.transform || null;
  }

  quad(): number[] {
    return this._quad;
  }

  anchorPoint(): number[] {
    return [
      this._layerPayload.anchorX || 0,
      this._layerPayload.anchorY || 0,
      this._layerPayload.anchorZ || 0,
    ];
  }

  invisible(): boolean {
    return this._layerPayload.invisible || false;
  }

  paintCount(): number {
    return this._paintCount || this._layerPayload.paintCount;
  }

  lastPaintRect(): Protocol.DOM.Rect|null {
    return this._lastPaintRect || null;
  }

  scrollRects(): Protocol.LayerTree.ScrollRect[] {
    return this._scrollRects;
  }

  stickyPositionConstraint(): SDK.LayerTreeBase.StickyPositionConstraint|null {
    return this._stickyPositionConstraint || null;
  }

  async requestCompositingReasonIds(): Promise<string[]> {
    const reasons = await this._layerTreeModel._layerTreeAgent.invoke_compositingReasons({layerId: this.id()});
    return reasons.compositingReasonIds || [];
  }

  drawsContent(): boolean {
    return this._layerPayload.drawsContent;
  }

  gpuMemoryUsage(): number {
    /**
     * @const
     */
    const bytesPerPixel = 4;
    return this.drawsContent() ? this.width() * this.height() * bytesPerPixel : 0;
  }

  snapshots(): Promise<SDK.PaintProfiler.SnapshotWithRect|null>[] {
    const promise = this._layerTreeModel._paintProfilerModel.makeSnapshot(this.id()).then(snapshot => {
      if (!snapshot) {
        return null;
      }
      return {rect: {x: 0, y: 0, width: this.width(), height: this.height()}, snapshot: snapshot};
    });
    return [promise];
  }

  _didPaint(rect: Protocol.DOM.Rect): void {
    this._lastPaintRect = rect;
    this._paintCount = this.paintCount() + 1;
    this._image = null;
  }

  _reset(layerPayload: Protocol.LayerTree.Layer): void {
    /** @type {?SDK.DOMModel.DOMNode} */
    this._node = null;
    this._children = [];
    this._parent = null;
    this._paintCount = 0;
    this._layerPayload = layerPayload;
    this._image = null;
    this._scrollRects = this._layerPayload.scrollRects || [];
    this._stickyPositionConstraint = this._layerPayload.stickyPositionConstraint ?
        new SDK.LayerTreeBase.StickyPositionConstraint(
            this._layerTreeModel.layerTree(), this._layerPayload.stickyPositionConstraint) :
        null;
  }

  _matrixFromArray(a: number[]): DOMMatrix {
    function toFixed9(x: number): string {
      return x.toFixed(9);
    }
    return new WebKitCSSMatrix('matrix3d(' + a.map(toFixed9).join(',') + ')');
  }

  _calculateTransformToViewport(parentTransform: DOMMatrix): DOMMatrix {
    const offsetMatrix = new WebKitCSSMatrix().translate(this._layerPayload.offsetX, this._layerPayload.offsetY);
    let matrix: DOMMatrix = offsetMatrix;

    if (this._layerPayload.transform) {
      const transformMatrix = this._matrixFromArray(this._layerPayload.transform);
      const anchorVector = new UI.Geometry.Vector(
          this._layerPayload.width * this.anchorPoint()[0], this._layerPayload.height * this.anchorPoint()[1],
          this.anchorPoint()[2]);
      const anchorPoint = UI.Geometry.multiplyVectorByMatrixAndNormalize(anchorVector, matrix);
      const anchorMatrix = new WebKitCSSMatrix().translate(-anchorPoint.x, -anchorPoint.y, -anchorPoint.z);
      matrix = anchorMatrix.inverse().multiply(transformMatrix.multiply(anchorMatrix.multiply(matrix)));
    }

    matrix = parentTransform.multiply(matrix);
    return matrix;
  }

  _createVertexArrayForRect(width: number, height: number): number[] {
    return [0, 0, 0, width, 0, 0, width, height, 0, 0, height, 0];
  }

  _calculateQuad(parentTransform: DOMMatrix): void {
    const matrix = this._calculateTransformToViewport(parentTransform);
    this._quad = [];
    const vertices = this._createVertexArrayForRect(this._layerPayload.width, this._layerPayload.height);
    for (let i = 0; i < 4; ++i) {
      const point = UI.Geometry.multiplyVectorByMatrixAndNormalize(
          new UI.Geometry.Vector(vertices[i * 3], vertices[i * 3 + 1], vertices[i * 3 + 2]), matrix);
      this._quad.push(point.x, point.y);
    }

    function calculateQuadForLayer(layer: AgentLayer): void {
      layer._calculateQuad(matrix);
    }

    this._children.forEach(calculateQuadForLayer);
  }
}

class LayerTreeDispatcher implements ProtocolProxyApi.LayerTreeDispatcher {
  _layerTreeModel: LayerTreeModel;
  constructor(layerTreeModel: LayerTreeModel) {
    this._layerTreeModel = layerTreeModel;
  }

  layerTreeDidChange({layers}: Protocol.LayerTree.LayerTreeDidChangeEvent): void {
    this._layerTreeModel._layerTreeChanged(layers || null);
  }

  layerPainted({layerId, clip}: Protocol.LayerTree.LayerPaintedEvent): void {
    this._layerTreeModel._layerPainted(layerId, clip);
  }
}