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Fix Firefox WASI module loading #8

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Merged
espmaniac merged 1 commit into from
Jul 12, 2026
Merged

Fix Firefox WASI module loading #8

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49 changes: 39 additions & 10 deletions main.js
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Original file line number Diff line number Diff line change
Expand Up @@ -55,17 +55,35 @@ function appendLog(message) {
consoleLog.scrollTop = consoleLog.scrollHeight;
}

function readCString(pointer) {
if (!runtime || !pointer) return '';
const bytes = [];
for (let index = pointer; runtime.HEAPU8[index] !== 0; index += 1) {
bytes.push(runtime.HEAPU8[index]);
}
return new TextDecoder().decode(Uint8Array.from(bytes));
}

function runtimeError() {
if (!runtime) return 'wasm-rtos runtime is not initialized';
const pointer = runtime.ccall('browser_runtime_get_last_error', 'number', [], []);
return pointer ? runtime.UTF8ToString(pointer) : 'unknown runtime error';
return pointer ? readCString(pointer) : 'unknown runtime error';
}

function callRuntime(name, returnType, argumentTypes = [], argumentsList = []) {
if (!runtime) throw new Error('wasm-rtos runtime is not initialized');
return runtime.ccall(name, returnType, argumentTypes, argumentsList);
}

async function detectEntryPoint(wasmBytes) {
const module = await WebAssembly.compile(wasmBytes);
const exports = WebAssembly.Module.exports(module).map((item) => item.name);
for (const candidate of ['app_main', '_start', 'main']) {
if (exports.includes(candidate)) return candidate;
}
throw new Error('No supported entry point found. Expected app_main, _start, or main.');
}

function stateToStatus(taskId) {
const state = callRuntime('browser_task_get_state', 'number', ['number'], [taskId]);
if (state === OS_TASK_READY) return 'Ready';
Expand All @@ -83,18 +101,27 @@ function stateToStatus(taskId) {
}

function createOsTask(task) {
const taskId = callRuntime(
'browser_task_create',
'number',
['array', 'number', 'string', 'string', 'number', 'number'],
[task.wasmBytes, task.wasmBytes.length, 'app_main', task.app, 64 * 1024, task.priority]
);
const wasmPointer = runtime._malloc(task.wasmBytes.length);
if (!wasmPointer) throw new Error('Unable to allocate memory for the guest module');

let taskId = 0;
try {
runtime.HEAPU8.set(task.wasmBytes, wasmPointer);
taskId = callRuntime(
'browser_task_create',
'number',
['number', 'number', 'string', 'string', 'number', 'number'],
[wasmPointer, task.wasmBytes.length, task.entryPoint, task.app, 64 * 1024, task.priority]
);
} finally {
runtime._free(wasmPointer);
}

if (!taskId) throw new Error(runtimeError());
task.osTaskId = taskId;
task.id = `task_${taskId}`;
task.status = 'Ready';
appendLog(`Started ${task.app} as ${task.id}`);
appendLog(`Started ${task.app} as ${task.id} using ${task.entryPoint}`);
}

function actionButtons(task) {
Expand Down Expand Up @@ -209,14 +236,16 @@ async function addFile(file) {
return;
}

const wasmBytes = new Uint8Array(await file.arrayBuffer());
const task = {
localId: crypto.randomUUID(),
id: 'pending',
app: file.name,
status: 'Ready',
priority: 5,
osTaskId: 0,
wasmBytes: new Uint8Array(await file.arrayBuffer())
wasmBytes,
entryPoint: await detectEntryPoint(wasmBytes)
};

try {
Expand All @@ -232,7 +261,7 @@ async function addFile(file) {
}

function handleFiles(files) {
Array.from(files).forEach((file) => addFile(file));
Array.from(files).forEach((file) => addFile(file).catch((error) => appendLog(`${file.name}: ${error.message}`)));
}

['click', 'keydown'].forEach((type) => {
Expand Down
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