support loading logs through postMessage in logviewer

scripts/logviewer/index.html

@@ -218,5 +218,20 @@
         <main></main>
         <aside></aside>
         <script type="module" src="main.js"></script>
+        <script type="module">
+            import {loadBlob} from "./main.js";
+            window.addEventListener("message", event => {
+                console.log("message", event);
+                if (event.data.type === "open") {
+                    document.getElementById("filename").innerText = "Loading logs from other tab...";
+                    loadBlob(event.data.logs).then(() => {
+                        document.getElementById("filename").innerText = "Logs from other tab at " + new Date();
+                    });
+                } else if (event.data.type === "ping") {
+                    document.getElementById("filename").innerText = "Waiting for logs from other tab...";
+                    event.source.postMessage({type: "pong"});
+                }
+            });
+        </script>
     </body>
 </html>

scripts/logviewer/main.js

@@ -164,7 +164,11 @@ function getRootItemHeader(prevItem, item) {
 async function loadFile() {
     const file = await openFile();
     document.getElementById("filename").innerText = file.name;
-    const json = await readFileAsText(file);
+    await loadBlob(file);
+}
+
+export async function loadBlob(blob) {
+    const json = await readFileAsText(blob);
     const logs = JSON.parse(json);
     logs.items.sort((a, b) => itemStart(a) - itemStart(b));
     rootItem = {c: logs.items};
@@ -181,6 +185,7 @@ async function loadFile() {
         return fragment;
     }, document.createDocumentFragment());
     main.replaceChildren(fragment);
+    main.scrollTop = main.scrollHeight;
 }
 
 // TODO: make this use processRecursively