Implement web install using fastboot.js

This implements the WebUSB-based web installer using fastboot.js to
act as a fastboot client. A bare minimum UI with a plain-text
status/progress caption for each step is included, as well as a plain
button to trigger it and basic error handling.

WebADB has been removed now that we are only using fastboot.js.

Initial features:

- Unlocking and locking the bootloader
- Downloading the latest GrapheneOS release available for the device
- Flashing the factory images zip
- Reusing USB connections

static/js/web-install.js

@@ -1,77 +1,102 @@
 // @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&dn=expat.txt MIT
 
-async function unlockBootloader() {
-    const webusb = await Adb.open("WebUSB");
+import { FastbootDevice } from "./fastboot/fastboot.js";
+import * as Factory from "./fastboot/factory.js";
 
-    if (!webusb.isFastboot()) {
-        console.log("error: not in fastboot mode");
+const RELEASES_URL = "https://releases.grapheneos.org";
+
+let device = new FastbootDevice();
+let lastReleaseZip = null;
+
+async function ensureConnected(setProgress) {
+    console.log(device.device);
+    if (!device.isConnected) {
+        setProgress("Connecting to device...");
+        await device.connect();
     }
-
-    console.log("connecting with fastboot");
-
-    const fastboot = await webusb.connectFastboot();
-    await fastboot.send("flashing unlock");
-    await fastboot.receive();
 }
 
-async function downloadRelease() {
-    const webusb = await Adb.open("WebUSB");
+async function unlockBootloader(setProgress) {
+    await ensureConnected(setProgress);
 
-    if (!webusb.isFastboot()) {
-        console.log("error: not in fastboot mode");
-    }
-
-    console.log("connecting with fastboot");
-
-    const fastboot = await webusb.connectFastboot();
-    await fastboot.send("getvar:product");
-    const response = await fastboot.receive();
-    if (fastboot.get_cmd(response) == "FAIL") {
-        throw new Error("getvar product failed");
-    }
-    const decoder = new TextDecoder();
-    const product = decoder.decode(fastboot.get_payload(response));
-
-    const baseUrl = "https://releases.grapheneos.org/";
-    const metadata = await (await fetch(baseUrl + product + "-stable")).text();
-    const buildNumber = metadata.split(" ")[0];
-    const downloadUrl = baseUrl + product + "-factory-" + buildNumber + ".zip";
-    console.log(downloadUrl);
-
-    // Download factory images
-    //
-    // Need to do this in a way that works well with huge files, particularly since the zip needs
-    // to be extracted. Could potentially split it up on the server if this works out badly.
+    setProgress("Unlocking bootloader...");
+    await device.runCommand("flashing unlock");
+    return "Bootloader unlocked.";
 }
 
-async function lockBootloader() {
-    const webusb = await Adb.open("WebUSB");
+async function downloadRelease(setProgress) {
+    await ensureConnected(setProgress);
 
-    if (!webusb.isFastboot()) {
-        console.log("error: not in fastboot mode");
-    }
+    setProgress("Getting device model...");
+    let product = await device.getVariable("product");
+    setProgress("Finding latest release...");
+    let metadataResp = await fetch(`${RELEASES_URL}/${product}-stable`);
+    let metadata = await metadataResp.text();
+    let releaseId = metadata.split(" ")[0];
 
-    console.log("connecting with fastboot");
-
-    const fastboot = await webusb.connectFastboot();
-    await fastboot.send("flashing lock");
-    await fastboot.receive();
+    // Download and cache the zip as a blob
+    setProgress(`Downloading ${releaseId} release for ${product}...`);
+    lastReleaseZip = `${product}-factory-${releaseId}.zip`;
+    await Factory.downloadZip(`${RELEASES_URL}/${lastReleaseZip}`);
+    return `Downloaded ${releaseId} release for ${product}.`;
 }
 
+async function flashRelease(setProgress) {
+    await ensureConnected(setProgress);
+
+    setProgress("Flashing release...");
+    await Factory.flashZip(device, lastReleaseZip, (action, partition) => {
+        let userPartition = partition == "avb_custom_key" ? "verified boot key" : partition;
+        if (action == "unpack") {
+            setProgress(`Unpacking image: ${userPartition}`);
+        } else {
+            setProgress(`Flashing image: ${userPartition}`);
+        }
+    });
+    return `Flashed ${lastReleaseZip} to device.`;
+}
+
+async function lockBootloader(setProgress) {
+    await ensureConnected(setProgress);
+
+    setProgress("Locking bootloader...");
+    await device.runCommand("flashing lock");
+    return "Bootloader locked.";
+}
+
+function addButtonHook(id, callback) {
+    let statusField = document.getElementById(`${id}-status`);
+    let statusCallback = (status) => {
+        statusField.textContent = status;
+        statusField.className = "";
+    };
+
+    let button = document.getElementById(`${id}-button`);
+    button.disabled = false;
+    button.onclick = async () => {
+        try {
+            let finalStatus = await callback(statusCallback);
+            statusCallback(finalStatus);
+        } catch (error) {
+            statusCallback(`Error: ${error.message}`);
+            statusField.className = "error-text";
+        }
+    };
+}
+
+// zip.js is loaded separately.
+// eslint-disable-next-line no-undef
+zip.configure({
+    workerScriptsPath: "/js/fastboot/libs/",
+});
+
 if ("usb" in navigator) {
     console.log("WebUSB available");
 
-    const unlockBootloaderButton = document.getElementById("unlock-bootloader");
-    unlockBootloaderButton.disabled = false;
-    unlockBootloaderButton.onclick = unlockBootloader;
-
-    const downloadReleaseButton = document.getElementById("download-release");
-    downloadReleaseButton.disabled = false;
-    downloadReleaseButton.onclick = downloadRelease;
-
-    const lockBootloaderButton = document.getElementById("lock-bootloader");
-    lockBootloaderButton.disabled = false;
-    lockBootloaderButton.onclick = lockBootloader;
+    addButtonHook("unlock-bootloader", unlockBootloader);
+    addButtonHook("download-release", downloadRelease);
+    addButtonHook("flash-release", flashRelease);
+    addButtonHook("lock-bootloader", lockBootloader);
 } else {
     console.log("WebUSB unavailable");
 }