Initial commit

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
This commit is contained in:
Vincent Batts 2024-12-13 21:19:16 +00:00
commit fc6fc03dbc
Signed by: vbatts
GPG key ID: E30EFAA812C6E5ED
10 changed files with 714 additions and 0 deletions

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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.

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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/

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playing with wasm again
* https://developer.mozilla.org/en-US/docs/WebAssembly
* https://go.dev/wiki/WebAssembly
* https://golangbot.com/webassembly-using-go/

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<!doctype html>
<html>
<head>
<meta charset="utf-8"/>
<script src="wasm_exec.js"></script>
<script>
const go = new Go();
WebAssembly.instantiateStreaming(fetch("json.wasm"), go.importObject).then((result) => {
go.run(result.instance);
});
</script>
</head>
<body></body>
</html>

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assets/json.wasm Executable file

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<!doctype html>
<!--
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.
-->
<html>
<head>
<meta charset="utf-8">
<title>Go wasm</title>
</head>
<body>
<!--
Add the following polyfill for Microsoft Edge 17/18 support:
<script src="https://cdn.jsdelivr.net/npm/text-encoding@0.7.0/lib/encoding.min.js"></script>
(see https://caniuse.com/#feat=textencoder)
-->
<script src="wasm_exec.js"></script>
<script>
if (!WebAssembly.instantiateStreaming) { // polyfill
WebAssembly.instantiateStreaming = async (resp, importObject) => {
const source = await (await resp).arrayBuffer();
return await WebAssembly.instantiate(source, importObject);
};
}
const go = new Go();
let mod, inst;
WebAssembly.instantiateStreaming(fetch("json.wasm"), go.importObject).then((result) => {
mod = result.module;
inst = result.instance;
document.getElementById("runButton").disabled = false;
}).catch((err) => {
console.error(err);
});
async function run() {
console.clear();
await go.run(inst);
inst = await WebAssembly.instantiate(mod, go.importObject); // reset instance
}
</script>
<button onClick="run();" id="runButton" disabled>Run</button>
</body>
</html>

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// 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;
};
}
}
})();

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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
}
}

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//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
}

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module git.batts.cloud/vbatts/webassembly
go 1.22.5