From 51c6e3da201b9b41e24f02efabd326e015d32b7b Mon Sep 17 00:00:00 2001
From: Vadim Korolik <vkorolik@gmail.com>
Date: Mon, 23 Sep 2024 15:17:11 -0500
Subject: [PATCH] improve canvas serialization performance

---
 packages/rrweb-snapshot/src/snapshot.ts       | 12 +++++--
 .../record/observers/canvas/canvas-manager.ts | 33 ++++++++++++++++---
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/packages/rrweb-snapshot/src/snapshot.ts b/packages/rrweb-snapshot/src/snapshot.ts
index 1f07858f..a665971d 100644
--- a/packages/rrweb-snapshot/src/snapshot.ts
+++ b/packages/rrweb-snapshot/src/snapshot.ts
@@ -518,7 +518,8 @@ function serializeTextNode(
     cssCaptured?: boolean;
   },
 ): serializedNode {
-  const { needsMask, maskTextFn, privacySetting, rootId, cssCaptured } = options;
+  const { needsMask, maskTextFn, privacySetting, rootId, cssCaptured } =
+    options;
   // The parent node may not be a html element which has a tagName attribute.
   // So just let it be undefined which is ok in this use case.
   const parent = dom.parentNode(n);
@@ -551,7 +552,11 @@ function serializeTextNode(
     n.parentElement?.getAttribute('data-hl-record');
   const obfuscateDefaultPrivacy =
     privacySetting === 'default' && shouldObfuscateTextByDefault(textContent);
-  if ((enableStrictPrivacy || obfuscateDefaultPrivacy) && !highlightOverwriteRecord && parentTagName) {
+  if (
+    (enableStrictPrivacy || obfuscateDefaultPrivacy) &&
+    !highlightOverwriteRecord &&
+    parentTagName
+  ) {
     const IGNORE_TAG_NAMES = new Set([
       'HEAD',
       'TITLE',
@@ -704,10 +709,13 @@ function serializeElementNode(
     if ((n as ICanvas).__context === '2d') {
       // only record this on 2d canvas
       if (!is2DCanvasBlank(n as HTMLCanvasElement)) {
+        /** Start of Highlight Code
+         * Avoid capturing non-blank 2d canvas here - defer to canvas-manager.ts for better performance
         attributes.rr_dataURL = (n as HTMLCanvasElement).toDataURL(
           dataURLOptions.type,
           dataURLOptions.quality,
         );
+        End of Highlight Code **/
       }
     } else if (!('__context' in n)) {
       // context is unknown, better not call getContext to trigger it
diff --git a/packages/rrweb/src/record/observers/canvas/canvas-manager.ts b/packages/rrweb/src/record/observers/canvas/canvas-manager.ts
index c2babfcb..33624653 100644
--- a/packages/rrweb/src/record/observers/canvas/canvas-manager.ts
+++ b/packages/rrweb/src/record/observers/canvas/canvas-manager.ts
@@ -142,7 +142,7 @@ export class CanvasManager {
             ],
           },
         ],
-      }
+      };
       this.debug(null, 'canvas worker recording mutation', mutation);
       this.mutationCb(mutation);
     };
@@ -337,9 +337,27 @@ export class CanvasManager {
     let rafId: number;
 
     const elementFoundTime: Map<number, number> = new Map();
+
+    const querySelectorAll = <T extends 'canvas' | 'video'>(
+      node: ParentNode,
+      selector: T,
+    ): (T extends 'canvas' ? HTMLCanvasElement : HTMLVideoElement)[] => {
+      type NodeType = T extends 'canvas' ? HTMLCanvasElement : HTMLVideoElement;
+      const nodes: NodeType[] = [];
+      node.querySelectorAll(selector).forEach((n) => nodes.push(n as NodeType));
+      const nodeIterator = document.createNodeIterator(node, Node.ELEMENT_NODE);
+      let currentNode: Element | null;
+      while ((currentNode = nodeIterator.nextNode() as Element | null)) {
+        if (currentNode?.shadowRoot) {
+          nodes.push(...querySelectorAll(currentNode.shadowRoot, selector));
+        }
+      }
+      return nodes;
+    };
+
     const getCanvas = (timestamp: DOMHighResTimeStamp): HTMLCanvasElement[] => {
       const matchedCanvas: HTMLCanvasElement[] = [];
-      win.document.querySelectorAll('canvas').forEach((canvas) => {
+      querySelectorAll(win.document, 'canvas').forEach((canvas) => {
         if (!isBlocked(canvas, blockClass, blockSelector, true)) {
           this.debug(canvas, 'discovered canvas');
           matchedCanvas.push(canvas);
@@ -355,7 +373,7 @@ export class CanvasManager {
     const getVideos = (timestamp: DOMHighResTimeStamp): HTMLVideoElement[] => {
       const matchedVideos: HTMLVideoElement[] = [];
       if (recordVideos) {
-        win.document.querySelectorAll('video').forEach((video) => {
+        querySelectorAll(win.document, 'video').forEach((video) => {
           if (video.src !== '' && video.src.indexOf('blob:') === -1) return;
           if (!isBlocked(video, blockClass, blockSelector, true)) {
             matchedVideos.push(video);
@@ -428,7 +446,14 @@ export class CanvasManager {
               // video is not yet ready... this retry on the next sampling iteration.
               // we don't want to crash the worker by sending an undefined bitmap
               // if the video is not yet rendered.
-              if (video.width === 0 || video.height === 0 || actualWidth === 0 || actualHeight === 0 || boxWidth === 0 || boxHeight === 0) {
+              if (
+                video.width === 0 ||
+                video.height === 0 ||
+                actualWidth === 0 ||
+                actualHeight === 0 ||
+                boxWidth === 0 ||
+                boxHeight === 0
+              ) {
                 this.debug(video, 'not yet ready', {
                   width: video.width,
                   height: video.height,