pass wasi instance directly to circom_runtime (#8)

Author: martyall

Diff for: app/Prover/Prove.js

@@ -1,38 +1,77 @@
 import { WASI, PreopenDirectory, File, OpenFile, ConsoleStdout } from "@bjorn3/browser_wasi_shim/dist";
-import { groth16, wtns } from "snarkjs";
+import { groth16 } from "snarkjs";
 
-async function load_external_file(path) {
-  const response = await fetch(path);
-  const buffer = await response.arrayBuffer();
-  return new File(buffer);
-}
+import * as fastFile from "fastfile";
+import { WitnessCalculatorBuilder } from "circom_runtime";
 
 async function _fullProve(input) {
-  const wasmFile = "circuit.wasm";
   const zkeyFile = "circuit_final.zkey";
-  let fds = [
+  let instance = await createWASMInstance();
+  const w = {
+    type: "mem"
+  };
+  await wtnsCalculate(input, instance, w);
+  const { proof, publicSignals } = await groth16.prove(zkeyFile, w);
+  return { proof, inputs: publicSignals };
+}
+
+export const fullProveImpl = input => () => _fullProve(input);
+
+async function createWASMInstance() {
+  let memorySize = 32767;
+  let memory;
+  let memoryAllocated = false;
+  while (!memoryAllocated) {
+    try {
+      memory = new WebAssembly.Memory({ initial: memorySize });
+      memoryAllocated = true;
+    } catch (err) {
+      if (memorySize === 1) {
+        throw err;
+      }
+      console.warn("Could not allocate " + memorySize * 1024 * 64 + " bytes. This may cause severe instability. Trying with " + memorySize * 1024 * 64 / 2 + " bytes");
+      memorySize = Math.floor(memorySize / 2);
+    }
+  }
+
+  const fds = [
     new OpenFile(new File([])), // stdin
     ConsoleStdout.lineBuffered(msg => console.log(`[WASI stdout] ${msg}`)),
     ConsoleStdout.lineBuffered(msg => console.warn(`[WASI stderr] ${msg}`)),
     new PreopenDirectory("/", [
       ["circuit.bin", await load_external_file("circuit.bin")]
     ])
   ];
+
   const wasi = new WASI([], [], fds, { debug: true });
-  let options = {
-    initializeWasiReactorModuleInstance: (instance) => {
-      wasi.initialize(instance);
-    },
-    additionalWASMImports: {
-      wasi_snapshot_preview1: wasi.wasiImport
-    }
-  };
-  const w = {
-        type: "mem"
-    };
-  await wtns.calculate(input, wasmFile, w, options);
-  const {proof, publicSignals} = await groth16.prove(zkeyFile, w);
-  return {proof, inputs: publicSignals};
-}
 
-export const fullProveImpl = input => () => _fullProve(input);
+  const fdWasm = await fastFile.readExisting("circuit.wasm");
+  const code = await fdWasm.read(fdWasm.totalSize);
+  await fdWasm.close();
+
+  const wasmModule = await WebAssembly.compile(code);
+
+  const instance = await WebAssembly.instantiate(wasmModule, { wasi_snapshot_preview1: wasi.wasiImport });
+
+  wasi.initialize(instance);
+
+  return instance;
+
+};
+
+async function wtnsCalculate(input, wasm, wtnsFileName) {
+
+  const wc = await WitnessCalculatorBuilder(wasm);
+  const fdWtns = await fastFile.createOverride(wtnsFileName);
+
+  const w = await wc.calculateWTNSBin(input);
+
+  await fdWtns.write(w);
+  await fdWtns.close();
+};
+
+async function load_external_file(path) {
+  const response = await fetch(path);
+  const buffer = await response.arrayBuffer();
+  return new File(buffer);
+};

Diff for: package-lock.json

@@ -37,10 +37,10 @@
     "keccak": "^3.0.0",
     "secp256k1": "^5.0.0",
     "snarkjs": "github:l-adic/snarkjs#actually-use-wasm-options",
-    "circom_runtime": "github:l-adic/circom_runtime#bbfe3eeb68e18dfcb4d5e24668e536b030741e31"
+    "circom_runtime": "github:l-adic/circom_runtime#968aaa5c7cf9f22dba72d939632778d78e57c56f"
   },
   "overrides": {
-    "circom_runtime": "github:l-adic/circom_runtime#bbfe3eeb68e18dfcb4d5e24668e536b030741e31"
+    "circom_runtime": "github:l-adic/circom_runtime#968aaa5c7cf9f22dba72d939632778d78e57c56f"
   },
   "parcel": {
     "aliases": {