add tracing feature

Author: kateinoigakukun

examples/main.js

@@ -1,10 +1,10 @@
-import { WASI, useAll } from "uwasi";
+import { WASI, useAll, useTrace } from "uwasi";
 import fs from "node:fs/promises";
 
 async function main() {
     const wasi = new WASI({
         args: process.argv.slice(2),
-        features: [useAll()],
+        features: [useTrace([useAll()])],
     });
     const bytes = await fs.readFile(process.argv[2]);
     const { instance } = await WebAssembly.instantiate(bytes, {

src/features/tracing.ts

@@ -0,0 +1,23 @@
+import { WASIFeatureProvider } from "../options";
+
+export function useTrace(features: WASIFeatureProvider[]): WASIFeatureProvider {
+    return (options, abi, memoryView) => {
+        let wasiImport: WebAssembly.ModuleImports = {};
+        for (const useFeature of features) {
+            const imports = useFeature(options, abi, memoryView);
+            wasiImport = { ...wasiImport, ...imports };
+        }
+        for (const key in wasiImport) {
+            const original = wasiImport[key];
+            if (typeof original !== 'function') {
+                continue;
+            }
+            wasiImport[key] = (...args: any[]) => {
+                const result = original(...args);
+                console.log(`[uwasi-tracing] ${key}(${args.map(a => JSON.stringify(a)).join(', ')}) => ${result}`);
+                return result;
+            }
+        }
+        return wasiImport;
+    }
+}

src/index.ts

@@ -8,6 +8,7 @@ export * from "./features/environ";
 export * from "./features/fd";
 export * from "./features/proc";
 export * from "./features/random";
+export * from "./features/tracing";
 
 export class WASI {
     /**