feat(vom): discover canvas candidates and resolve visible regions

apps/extension/src/tools/vom/__tests__/facts.test.ts

@@ -80,6 +80,19 @@ describe("document facts", () => {
       boundsSpace: "snapshot-document-layout",
       bounds: [10, 20, 120, 40],
       styles: {
+        rotate: "auto",
+        scale: "auto",
+        perspective: "auto",
+        clip: "auto",
+        contain: "auto",
+        "overflow-clip-margin": "auto",
+        display: "auto",
+        "overflow-x": "auto",
+        "overflow-y": "auto",
+        transform: "auto",
+        zoom: "auto",
+        "clip-path": "auto",
+        "mask-image": "auto",
         position: "static",
         "pointer-events": "auto",
         cursor: "auto",
@@ -125,3 +138,42 @@ describe("document facts", () => {
     expect(reads).toBeLessThanOrEqual(356);
   });
 });
+
+describe("visual ancestry facts", () => {
+  it("distinguishes document roots, malformed roots, missing parents and cycles", async () => {
+    const input = [
+      { ...node(0, null), nodeType: 9 },
+      { ...node(1, 0), nodeType: 1 },
+      { ...node(2, 1), nodeType: 11 },
+      node(3, 2),
+      node(4, 99),
+      node(5, 6),
+      node(6, 5),
+      node(7, 5),
+      { ...node(8, null), nodeType: 1 },
+      { ...node(9, null), nodeType: 9, parentMissing: true },
+    ];
+    const index = await buildDocumentIndex(input.reverse());
+    for (const id of [0, 1, 2, 3]) expect(index.ancestryComplete.get(id)).toBe(true);
+    for (const id of [4, 5, 6, 7, 8, 9]) expect(index.ancestryComplete.get(id)).toBe(false);
+  });
+
+  it("retains client offsets in their source units and does not disguise missing parent indices", async () => {
+    const decoded = await decodeDocument(
+      {
+        nodes: { backendNodeId: [1, 2], nodeType: [1, 1], nodeName: [0, 0], parentIndex: [99] },
+        layout: {
+          nodeIndex: [0],
+          bounds: [[745, 455.625, 97, 59.5]],
+          clientRects: [[5, 5, 68, 38]],
+        },
+      },
+      ["div"],
+    );
+    expect(decoded.nodes[0].layout?.clientRect).toEqual([5, 5, 68, 38]);
+    expect(decoded.nodes[0].layout?.bounds).toEqual([745, 455.625, 97, 59.5]);
+    expect(decoded.nodes.every((node) => node.parentMissing)).toBe(true);
+    const index = await buildDocumentIndex(decoded.nodes);
+    expect([...index.ancestryComplete.values()]).toEqual([false, false]);
+  });
+});