Go wasm

commit fc6fc03dbc2c4c1abd058bd31fec4906ecc95bc7 Author: Vincent Batts Date: Fri Dec 13 21:19:16 2024 +0000 Initial commit Signed-off-by: Vincent Batts diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..6cae566 --- /dev/null +++ b/LICENSE @@ -0,0 +1,9 @@ +MIT License + +Copyright (c) 2024 vbatts + +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..54c5651 --- /dev/null +++ b/Makefile @@ -0,0 +1,12 @@ + +default: assets/json.wasm + +assets/json.wasm: cmd/wasm/main.go + GOOS=js GOARCH=wasm go build -o $@ $< + +run: server + ./server + +server: cmd/server/main.go assets/json.wasm + go build -o server ./cmd/server/ + diff --git a/README.md b/README.md new file mode 100644 index 0000000..6704c26 --- /dev/null +++ b/README.md @@ -0,0 +1,5 @@ +playing with wasm again + +* https://developer.mozilla.org/en-US/docs/WebAssembly +* https://go.dev/wiki/WebAssembly +* https://golangbot.com/webassembly-using-go/ diff --git a/assets/index.html b/assets/index.html new file mode 100644 index 0000000..d5b0c2a --- /dev/null +++ b/assets/index.html @@ -0,0 +1,14 @@ + + + + + + + + + diff --git a/assets/json.wasm b/assets/json.wasm new file mode 100755 index 0000000..485bb23 Binary files /dev/null and b/assets/json.wasm differ diff --git a/assets/wasm_exec.html b/assets/wasm_exec.html new file mode 100644 index 0000000..6d38f61 --- /dev/null +++ b/assets/wasm_exec.html @@ -0,0 +1,49 @@ + + + + + + + Go wasm + + + + + + + + + + + diff --git a/assets/wasm_exec.js b/assets/wasm_exec.js new file mode 100644 index 0000000..bc6f210 --- /dev/null +++ b/assets/wasm_exec.js @@ -0,0 +1,561 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +"use strict"; + +(() => { + const enosys = () => { + const err = new Error("not implemented"); + err.code = "ENOSYS"; + return err; + }; + + if (!globalThis.fs) { + let outputBuf = ""; + globalThis.fs = { + constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused + writeSync(fd, buf) { + outputBuf += decoder.decode(buf); + const nl = outputBuf.lastIndexOf("\n"); + if (nl != -1) { + console.log(outputBuf.substring(0, nl)); + outputBuf = outputBuf.substring(nl + 1); + } + return buf.length; + }, + write(fd, buf, offset, length, position, callback) { + if (offset !== 0 || length !== buf.length || position !== null) { + callback(enosys()); + return; + } + const n = this.writeSync(fd, buf); + callback(null, n); + }, + chmod(path, mode, callback) { callback(enosys()); }, + chown(path, uid, gid, callback) { callback(enosys()); }, + close(fd, callback) { callback(enosys()); }, + fchmod(fd, mode, callback) { callback(enosys()); }, + fchown(fd, uid, gid, callback) { callback(enosys()); }, + fstat(fd, callback) { callback(enosys()); }, + fsync(fd, callback) { callback(null); }, + ftruncate(fd, length, callback) { callback(enosys()); }, + lchown(path, uid, gid, callback) { callback(enosys()); }, + link(path, link, callback) { callback(enosys()); }, + lstat(path, callback) { callback(enosys()); }, + mkdir(path, perm, callback) { callback(enosys()); }, + open(path, flags, mode, callback) { callback(enosys()); }, + read(fd, buffer, offset, length, position, callback) { callback(enosys()); }, + readdir(path, callback) { callback(enosys()); }, + readlink(path, callback) { callback(enosys()); }, + rename(from, to, callback) { callback(enosys()); }, + rmdir(path, callback) { callback(enosys()); }, + stat(path, callback) { callback(enosys()); }, + symlink(path, link, callback) { callback(enosys()); }, + truncate(path, length, callback) { callback(enosys()); }, + unlink(path, callback) { callback(enosys()); }, + utimes(path, atime, mtime, callback) { callback(enosys()); }, + }; + } + + if (!globalThis.process) { + globalThis.process = { + getuid() { return -1; }, + getgid() { return -1; }, + geteuid() { return -1; }, + getegid() { return -1; }, + getgroups() { throw enosys(); }, + pid: -1, + ppid: -1, + umask() { throw enosys(); }, + cwd() { throw enosys(); }, + chdir() { throw enosys(); }, + } + } + + if (!globalThis.crypto) { + throw new Error("globalThis.crypto is not available, polyfill required (crypto.getRandomValues only)"); + } + + if (!globalThis.performance) { + throw new Error("globalThis.performance is not available, polyfill required (performance.now only)"); + } + + if (!globalThis.TextEncoder) { + throw new Error("globalThis.TextEncoder is not available, polyfill required"); + } + + if (!globalThis.TextDecoder) { + throw new Error("globalThis.TextDecoder is not available, polyfill required"); + } + + const encoder = new TextEncoder("utf-8"); + const decoder = new TextDecoder("utf-8"); + + globalThis.Go = class { + constructor() { + this.argv = ["js"]; + this.env = {}; + this.exit = (code) => { + if (code !== 0) { + console.warn("exit code:", code); + } + }; + this._exitPromise = new Promise((resolve) => { + this._resolveExitPromise = resolve; + }); + this._pendingEvent = null; + this._scheduledTimeouts = new Map(); + this._nextCallbackTimeoutID = 1; + + const setInt64 = (addr, v) => { + this.mem.setUint32(addr + 0, v, true); + this.mem.setUint32(addr + 4, Math.floor(v / 4294967296), true); + } + + const setInt32 = (addr, v) => { + this.mem.setUint32(addr + 0, v, true); + } + + const getInt64 = (addr) => { + const low = this.mem.getUint32(addr + 0, true); + const high = this.mem.getInt32(addr + 4, true); + return low + high * 4294967296; + } + + const loadValue = (addr) => { + const f = this.mem.getFloat64(addr, true); + if (f === 0) { + return undefined; + } + if (!isNaN(f)) { + return f; + } + + const id = this.mem.getUint32(addr, true); + return this._values[id]; + } + + const storeValue = (addr, v) => { + const nanHead = 0x7FF80000; + + if (typeof v === "number" && v !== 0) { + if (isNaN(v)) { + this.mem.setUint32(addr + 4, nanHead, true); + this.mem.setUint32(addr, 0, true); + return; + } + this.mem.setFloat64(addr, v, true); + return; + } + + if (v === undefined) { + this.mem.setFloat64(addr, 0, true); + return; + } + + let id = this._ids.get(v); + if (id === undefined) { + id = this._idPool.pop(); + if (id === undefined) { + id = this._values.length; + } + this._values[id] = v; + this._goRefCounts[id] = 0; + this._ids.set(v, id); + } + this._goRefCounts[id]++; + let typeFlag = 0; + switch (typeof v) { + case "object": + if (v !== null) { + typeFlag = 1; + } + break; + case "string": + typeFlag = 2; + break; + case "symbol": + typeFlag = 3; + break; + case "function": + typeFlag = 4; + break; + } + this.mem.setUint32(addr + 4, nanHead | typeFlag, true); + this.mem.setUint32(addr, id, true); + } + + const loadSlice = (addr) => { + const array = getInt64(addr + 0); + const len = getInt64(addr + 8); + return new Uint8Array(this._inst.exports.mem.buffer, array, len); + } + + const loadSliceOfValues = (addr) => { + const array = getInt64(addr + 0); + const len = getInt64(addr + 8); + const a = new Array(len); + for (let i = 0; i < len; i++) { + a[i] = loadValue(array + i * 8); + } + return a; + } + + const loadString = (addr) => { + const saddr = getInt64(addr + 0); + const len = getInt64(addr + 8); + return decoder.decode(new DataView(this._inst.exports.mem.buffer, saddr, len)); + } + + const timeOrigin = Date.now() - performance.now(); + this.importObject = { + _gotest: { + add: (a, b) => a + b, + }, + gojs: { + // Go's SP does not change as long as no Go code is running. Some operations (e.g. calls, getters and setters) + // may synchronously trigger a Go event handler. This makes Go code get executed in the middle of the imported + // function. A goroutine can switch to a new stack if the current stack is too small (see morestack function). + // This changes the SP, thus we have to update the SP used by the imported function. + + // func wasmExit(code int32) + "runtime.wasmExit": (sp) => { + sp >>>= 0; + const code = this.mem.getInt32(sp + 8, true); + this.exited = true; + delete this._inst; + delete this._values; + delete this._goRefCounts; + delete this._ids; + delete this._idPool; + this.exit(code); + }, + + // func wasmWrite(fd uintptr, p unsafe.Pointer, n int32) + "runtime.wasmWrite": (sp) => { + sp >>>= 0; + const fd = getInt64(sp + 8); + const p = getInt64(sp + 16); + const n = this.mem.getInt32(sp + 24, true); + fs.writeSync(fd, new Uint8Array(this._inst.exports.mem.buffer, p, n)); + }, + + // func resetMemoryDataView() + "runtime.resetMemoryDataView": (sp) => { + sp >>>= 0; + this.mem = new DataView(this._inst.exports.mem.buffer); + }, + + // func nanotime1() int64 + "runtime.nanotime1": (sp) => { + sp >>>= 0; + setInt64(sp + 8, (timeOrigin + performance.now()) * 1000000); + }, + + // func walltime() (sec int64, nsec int32) + "runtime.walltime": (sp) => { + sp >>>= 0; + const msec = (new Date).getTime(); + setInt64(sp + 8, msec / 1000); + this.mem.setInt32(sp + 16, (msec % 1000) * 1000000, true); + }, + + // func scheduleTimeoutEvent(delay int64) int32 + "runtime.scheduleTimeoutEvent": (sp) => { + sp >>>= 0; + const id = this._nextCallbackTimeoutID; + this._nextCallbackTimeoutID++; + this._scheduledTimeouts.set(id, setTimeout( + () => { + this._resume(); + while (this._scheduledTimeouts.has(id)) { + // for some reason Go failed to register the timeout event, log and try again + // (temporary workaround for https://github.com/golang/go/issues/28975) + console.warn("scheduleTimeoutEvent: missed timeout event"); + this._resume(); + } + }, + getInt64(sp + 8), + )); + this.mem.setInt32(sp + 16, id, true); + }, + + // func clearTimeoutEvent(id int32) + "runtime.clearTimeoutEvent": (sp) => { + sp >>>= 0; + const id = this.mem.getInt32(sp + 8, true); + clearTimeout(this._scheduledTimeouts.get(id)); + this._scheduledTimeouts.delete(id); + }, + + // func getRandomData(r []byte) + "runtime.getRandomData": (sp) => { + sp >>>= 0; + crypto.getRandomValues(loadSlice(sp + 8)); + }, + + // func finalizeRef(v ref) + "syscall/js.finalizeRef": (sp) => { + sp >>>= 0; + const id = this.mem.getUint32(sp + 8, true); + this._goRefCounts[id]--; + if (this._goRefCounts[id] === 0) { + const v = this._values[id]; + this._values[id] = null; + this._ids.delete(v); + this._idPool.push(id); + } + }, + + // func stringVal(value string) ref + "syscall/js.stringVal": (sp) => { + sp >>>= 0; + storeValue(sp + 24, loadString(sp + 8)); + }, + + // func valueGet(v ref, p string) ref + "syscall/js.valueGet": (sp) => { + sp >>>= 0; + const result = Reflect.get(loadValue(sp + 8), loadString(sp + 16)); + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 32, result); + }, + + // func valueSet(v ref, p string, x ref) + "syscall/js.valueSet": (sp) => { + sp >>>= 0; + Reflect.set(loadValue(sp + 8), loadString(sp + 16), loadValue(sp + 32)); + }, + + // func valueDelete(v ref, p string) + "syscall/js.valueDelete": (sp) => { + sp >>>= 0; + Reflect.deleteProperty(loadValue(sp + 8), loadString(sp + 16)); + }, + + // func valueIndex(v ref, i int) ref + "syscall/js.valueIndex": (sp) => { + sp >>>= 0; + storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16))); + }, + + // valueSetIndex(v ref, i int, x ref) + "syscall/js.valueSetIndex": (sp) => { + sp >>>= 0; + Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24)); + }, + + // func valueCall(v ref, m string, args []ref) (ref, bool) + "syscall/js.valueCall": (sp) => { + sp >>>= 0; + try { + const v = loadValue(sp + 8); + const m = Reflect.get(v, loadString(sp + 16)); + const args = loadSliceOfValues(sp + 32); + const result = Reflect.apply(m, v, args); + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 56, result); + this.mem.setUint8(sp + 64, 1); + } catch (err) { + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 56, err); + this.mem.setUint8(sp + 64, 0); + } + }, + + // func valueInvoke(v ref, args []ref) (ref, bool) + "syscall/js.valueInvoke": (sp) => { + sp >>>= 0; + try { + const v = loadValue(sp + 8); + const args = loadSliceOfValues(sp + 16); + const result = Reflect.apply(v, undefined, args); + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 40, result); + this.mem.setUint8(sp + 48, 1); + } catch (err) { + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 40, err); + this.mem.setUint8(sp + 48, 0); + } + }, + + // func valueNew(v ref, args []ref) (ref, bool) + "syscall/js.valueNew": (sp) => { + sp >>>= 0; + try { + const v = loadValue(sp + 8); + const args = loadSliceOfValues(sp + 16); + const result = Reflect.construct(v, args); + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 40, result); + this.mem.setUint8(sp + 48, 1); + } catch (err) { + sp = this._inst.exports.getsp() >>> 0; // see comment above + storeValue(sp + 40, err); + this.mem.setUint8(sp + 48, 0); + } + }, + + // func valueLength(v ref) int + "syscall/js.valueLength": (sp) => { + sp >>>= 0; + setInt64(sp + 16, parseInt(loadValue(sp + 8).length)); + }, + + // valuePrepareString(v ref) (ref, int) + "syscall/js.valuePrepareString": (sp) => { + sp >>>= 0; + const str = encoder.encode(String(loadValue(sp + 8))); + storeValue(sp + 16, str); + setInt64(sp + 24, str.length); + }, + + // valueLoadString(v ref, b []byte) + "syscall/js.valueLoadString": (sp) => { + sp >>>= 0; + const str = loadValue(sp + 8); + loadSlice(sp + 16).set(str); + }, + + // func valueInstanceOf(v ref, t ref) bool + "syscall/js.valueInstanceOf": (sp) => { + sp >>>= 0; + this.mem.setUint8(sp + 24, (loadValue(sp + 8) instanceof loadValue(sp + 16)) ? 1 : 0); + }, + + // func copyBytesToGo(dst []byte, src ref) (int, bool) + "syscall/js.copyBytesToGo": (sp) => { + sp >>>= 0; + const dst = loadSlice(sp + 8); + const src = loadValue(sp + 32); + if (!(src instanceof Uint8Array || src instanceof Uint8ClampedArray)) { + this.mem.setUint8(sp + 48, 0); + return; + } + const toCopy = src.subarray(0, dst.length); + dst.set(toCopy); + setInt64(sp + 40, toCopy.length); + this.mem.setUint8(sp + 48, 1); + }, + + // func copyBytesToJS(dst ref, src []byte) (int, bool) + "syscall/js.copyBytesToJS": (sp) => { + sp >>>= 0; + const dst = loadValue(sp + 8); + const src = loadSlice(sp + 16); + if (!(dst instanceof Uint8Array || dst instanceof Uint8ClampedArray)) { + this.mem.setUint8(sp + 48, 0); + return; + } + const toCopy = src.subarray(0, dst.length); + dst.set(toCopy); + setInt64(sp + 40, toCopy.length); + this.mem.setUint8(sp + 48, 1); + }, + + "debug": (value) => { + console.log(value); + }, + } + }; + } + + async run(instance) { + if (!(instance instanceof WebAssembly.Instance)) { + throw new Error("Go.run: WebAssembly.Instance expected"); + } + this._inst = instance; + this.mem = new DataView(this._inst.exports.mem.buffer); + this._values = [ // JS values that Go currently has references to, indexed by reference id + NaN, + 0, + null, + true, + false, + globalThis, + this, + ]; + this._goRefCounts = new Array(this._values.length).fill(Infinity); // number of references that Go has to a JS value, indexed by reference id + this._ids = new Map([ // mapping from JS values to reference ids + [0, 1], + [null, 2], + [true, 3], + [false, 4], + [globalThis, 5], + [this, 6], + ]); + this._idPool = []; // unused ids that have been garbage collected + this.exited = false; // whether the Go program has exited + + // Pass command line arguments and environment variables to WebAssembly by writing them to the linear memory. + let offset = 4096; + + const strPtr = (str) => { + const ptr = offset; + const bytes = encoder.encode(str + "\0"); + new Uint8Array(this.mem.buffer, offset, bytes.length).set(bytes); + offset += bytes.length; + if (offset % 8 !== 0) { + offset += 8 - (offset % 8); + } + return ptr; + }; + + const argc = this.argv.length; + + const argvPtrs = []; + this.argv.forEach((arg) => { + argvPtrs.push(strPtr(arg)); + }); + argvPtrs.push(0); + + const keys = Object.keys(this.env).sort(); + keys.forEach((key) => { + argvPtrs.push(strPtr(`${key}=${this.env[key]}`)); + }); + argvPtrs.push(0); + + const argv = offset; + argvPtrs.forEach((ptr) => { + this.mem.setUint32(offset, ptr, true); + this.mem.setUint32(offset + 4, 0, true); + offset += 8; + }); + + // The linker guarantees global data starts from at least wasmMinDataAddr. + // Keep in sync with cmd/link/internal/ld/data.go:wasmMinDataAddr. + const wasmMinDataAddr = 4096 + 8192; + if (offset >= wasmMinDataAddr) { + throw new Error("total length of command line and environment variables exceeds limit"); + } + + this._inst.exports.run(argc, argv); + if (this.exited) { + this._resolveExitPromise(); + } + await this._exitPromise; + } + + _resume() { + if (this.exited) { + throw new Error("Go program has already exited"); + } + this._inst.exports.resume(); + if (this.exited) { + this._resolveExitPromise(); + } + } + + _makeFuncWrapper(id) { + const go = this; + return function () { + const event = { id: id, this: this, args: arguments }; + go._pendingEvent = event; + go._resume(); + return event.result; + }; + } + } +})(); diff --git a/cmd/server/main.go b/cmd/server/main.go new file mode 100644 index 0000000..ecfd29c --- /dev/null +++ b/cmd/server/main.go @@ -0,0 +1,15 @@ +package main + +import ( + "fmt" + "net/http" +) + +func main() { + fmt.Println("listening on http://localhost:9090/") + err := http.ListenAndServe(":9090", http.FileServer(http.Dir("./assets"))) + if err != nil { + fmt.Println("Failed to start server", err) + return + } +} diff --git a/cmd/wasm/main.go b/cmd/wasm/main.go new file mode 100644 index 0000000..113cf08 --- /dev/null +++ b/cmd/wasm/main.go @@ -0,0 +1,46 @@ +//go:build js && wasm + +package main + +import ( + "encoding/json" + "fmt" + "syscall/js" +) + +func main() { + js.Global().Set("formatJSON", jsonWrapper()) + fmt.Println("loaded golang wasm") + <-make(chan struct{}) +} + +func prettyJson(input string) (string, error) { + var raw any + if err := json.Unmarshal([]byte(input), &raw); err != nil { + return "", err + } + + pretty, err := json.MarshalIndent(raw, "", " ") + if err != nil { + return "", err + } + + return string(pretty), nil +} + +func jsonWrapper() js.Func { + jsonFunc := js.FuncOf(func(this js.Value, args []js.Value) any { + if len(args) != 1 { + return "Invalid no of arguments passed" + } + inputJSON := args[0].String() + fmt.Printf("input %s\n", inputJSON) + pretty, err := prettyJson(inputJSON) + if err != nil { + fmt.Printf("unable to convert to json %s\n", err) + return err.Error() + } + return pretty + }) + return jsonFunc +} diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..685df08 --- /dev/null +++ b/go.mod @@ -0,0 +1,3 @@ +module git.batts.cloud/vbatts/webassembly + +go 1.22.5