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Simplify WebAssembly logging and buffer handling #21

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Merged
ikskuh merged 1 commit into from
Jan 4, 2026
Merged

Simplify WebAssembly logging and buffer handling #21

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15 changes: 15 additions & 0 deletions build.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@ pub fn build(b: *std.Build) void {
// Targets:
const run_step = b.step("run", "Run the app");
const test_step = b.step("test", "Run unit tests");
const wasm_target = b.resolveTargetQuery(.{ .cpu_arch = .wasm32, .os_tag = .freestanding });

// Build:
const hyperdoc = b.addModule("hyperdoc", .{
Expand All @@ -60,6 +61,20 @@ pub fn build(b: *std.Build) void {
});
b.installArtifact(exe);

const wasm_exe = b.addExecutable(.{
.name = "hyperdoc_wasm",
.root_module = b.createModule(.{
.root_source_file = b.path("src/wasm.zig"),
.target = wasm_target,
.optimize = optimize,
.single_threaded = true,
.imports = &.{
.{ .name = "hyperdoc", .module = hyperdoc },
},
}),
});
b.installArtifact(wasm_exe);

const run_cmd = b.addRunArtifact(exe);
run_cmd.step.dependOn(b.getInstallStep());
if (b.args) |arg| {
Expand Down
284 changes: 284 additions & 0 deletions src/playground.html
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@@ -0,0 +1,284 @@
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>HyperDoc Playground</title>
<style>
:root {
color-scheme: light dark;
font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

body {
margin: 0;
height: 100vh;
display: flex;
flex-direction: column;
background: #f8f9fb;
}

header {
padding: 12px 16px;
font-size: 18px;
font-weight: 600;
border-bottom: 1px solid #d8dde6;
background: #ffffff;
}

.layout {
flex: 1;
display: grid;
grid-template-columns: 1fr 1fr;
gap: 12px;
padding: 12px;
box-sizing: border-box;
}

.pane {
display: flex;
flex-direction: column;
border: 1px solid #d8dde6;
border-radius: 8px;
background: #ffffff;
overflow: hidden;
}

.pane-header {
padding: 10px 12px;
font-weight: 600;
border-bottom: 1px solid #e4e7ed;
display: flex;
align-items: center;
justify-content: space-between;
gap: 8px;
}

textarea {
flex: 1;
width: 100%;
border: none;
padding: 12px;
resize: none;
font-family: "JetBrains Mono", Consolas, "Courier New", monospace;
font-size: 14px;
box-sizing: border-box;
outline: none;
}

.preview {
flex: 1;
padding: 12px;
overflow: auto;
box-sizing: border-box;
}

.diagnostics {
list-style: none;
margin: 0;
padding: 12px;
border-top: 1px solid #e4e7ed;
max-height: 180px;
overflow: auto;
display: none;
gap: 8px;
flex-direction: column;
background: #fff6f6;
}

.diagnostics.visible {
display: flex;
}

.diagnostics li {
margin: 0;
padding: 8px 10px;
background: #ffe3e3;
border: 1px solid #ffc2c2;
border-radius: 6px;
font-family: "JetBrains Mono", Consolas, "Courier New", monospace;
font-size: 13px;
}

.status {
font-size: 13px;
color: #4a5568;
}

.status.error {
color: #c53030;
font-weight: 600;
}

.status.ok {
color: #2f855a;
font-weight: 600;
}
</style>
</head>
<body>
<header>HyperDoc Playground</header>
<div class="layout">
<section class="pane">
<div class="pane-header">
<span>HyperDoc Source</span>
<span class="status" id="left-status">Waiting for WASM…</span>
</div>
<textarea id="source" aria-label="HyperDoc source"></textarea>
</section>
<section class="pane">
<div class="pane-header">
<span>Preview</span>
<span class="status" id="render-status"></span>
</div>
<div class="preview" id="preview"></div>
<ul class="diagnostics" id="diagnostics"></ul>
</section>
</div>
<script type="module">
const sourceField = document.getElementById("source");
const preview = document.getElementById("preview");
const diagnosticsList = document.getElementById("diagnostics");
const renderStatus = document.getElementById("render-status");
const leftStatus = document.getElementById("left-status");

const encoder = new TextEncoder();
const decoder = new TextDecoder();
const wasmUrl = "./hyperdoc_wasm.wasm";

const initialText = `hdoc(version="2.0", lang="en");
title {
HyperDoc Playground
}

paragraph {
Type HyperDoc content on the left to render HTML here.
}`;

sourceField.value = initialText;

function setStatus(text, className) {
renderStatus.textContent = text;
renderStatus.className = `status ${className ?? ""}`.trim();
}

function setDiagnostics(items) {
diagnosticsList.replaceChildren();
if (items.length === 0) {
diagnosticsList.classList.remove("visible");
return;
}

items.forEach((item) => {
const li = document.createElement("li");
li.textContent = `Line ${item.line}, Column ${item.column}: ${item.message}`;
diagnosticsList.append(li);
});
diagnosticsList.classList.add("visible");
}

async function bootstrap() {
try {
const logs = {
buffer: "",
reset() {
this.buffer = "";
},
append(ptr, len, memory) {
if (len === 0 || ptr === 0 || !memory) return;
const chunk = new Uint8Array(memory.buffer, ptr, len);
this.buffer += decoder.decode(chunk);
},
flush(level) {
const msg = this.buffer;
this.reset();
const method = ["error", "warn", "info", "debug"][level] ?? "log";
console[method](msg);
},
};

const importObject = {
env: {
reset_log() {
logs.reset();
},
append_log(ptr, len) {
logs.append(ptr, len, wasmMemory);
},
flush_log(level) {
logs.flush(level);
},
},
};

const response = await fetch(wasmUrl);
const bytes = await response.arrayBuffer();
const { instance } = await WebAssembly.instantiate(bytes, importObject);
const wasm = instance.exports;
let wasmMemory = wasm.memory;

leftStatus.textContent = "WASM ready";

function getMemory() {
wasmMemory = wasm.memory || wasmMemory;
return wasmMemory;
}

function process() {
const text = sourceField.value;
const data = encoder.encode(text);
if (!wasm.hdoc_set_document_len(data.length)) {
setStatus("Allocation failed", "error");
setDiagnostics([]);
preview.textContent = "";
return;
}

const ptr = wasm.hdoc_document_ptr();

const memory = getMemory();
if (data.length > 0 && memory && ptr !== 0) {
new Uint8Array(memory.buffer, ptr, data.length).set(data);
}

const ok = wasm.hdoc_process() !== 0;

if (ok) {
const htmlPtr = wasm.hdoc_html_ptr();
const htmlLen = wasm.hdoc_html_len();
const htmlBytes = htmlLen === 0 ? new Uint8Array() : new Uint8Array(getMemory().buffer, htmlPtr, htmlLen);
preview.innerHTML = decoder.decode(htmlBytes);
setStatus("Rendered", "ok");
setDiagnostics([]);
} else {
preview.innerHTML = "";
const count = wasm.hdoc_diagnostic_count();
const entries = [];
for (let i = 0; i < count; i += 1) {
const msgPtr = wasm.hdoc_diagnostic_message_ptr(i);
const msgLen = wasm.hdoc_diagnostic_message_len(i);
const message = msgLen === 0 ? "" : decoder.decode(new Uint8Array(getMemory().buffer, msgPtr, msgLen));
entries.push({
line: wasm.hdoc_diagnostic_line(i),
column: wasm.hdoc_diagnostic_column(i),
message,
});
}
setStatus("Diagnostics found", "error");
setDiagnostics(entries);
}
}

sourceField.addEventListener("input", process);
process();
} catch (error) {
leftStatus.textContent = "Failed to load WASM";
setStatus("Unable to start playground", "error");
diagnosticsList.classList.add("visible");
diagnosticsList.textContent = String(error);
}
}

bootstrap();
</script>
</body>
</html>
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