John Dvorak
109 lines
3.9 KiB
JavaScript
109 lines
3.9 KiB
JavaScript
// index.js — Greenshades native N-API loader (lazy).
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//
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// The Zig backend's napi_register_module_v1 entry point performs a
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// ServiceCellPool.init that forks 4 child processes. On non-Linux, in
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// containers without seccomp, or in test runners that don't intend to
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// exercise the native code, this fork sequence can corrupt glibc's heap
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// or simply block for ~4 seconds (one blocked read per cell).
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//
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// To avoid loading the binary on import (which would run that init at
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// unpredictable times), the binary is loaded LAZILY — only when a
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// caller actually accesses an export. Detection at module-load time
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// uses a synchronous fs stat call to confirm the prebuild exists.
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//
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// Env vars:
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// GREENSHADES_ZIG_NATIVE=1 — prefer a freshly-built zig-out/ binary
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// over the bundled prebuild
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// GREENSHADES_ZIG_SKIP=1 — disable native loading entirely (use
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// synthetic JS-only stubs for tests)
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'use strict';
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const os = require('os');
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const fs = require('fs');
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const path = require('path');
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function platformArch() {
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const p = os.platform();
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const a = os.arch();
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if (p === 'linux' && a === 'x64') return 'x86_64-linux';
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if (p === 'linux' && a === 'arm64') return 'aarch64-linux';
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return null;
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}
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const platformKey = platformArch();
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const useBuilt = process.env.GREENSHADES_ZIG_NATIVE === '1';
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const skipNative = process.env.GREENSHADES_ZIG_SKIP === '1';
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function candidatePath() {
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if (useBuilt) {
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const built = path.join(__dirname, '..', 'zig-out', 'greenshades_backend.node');
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if (fs.existsSync(built)) return built;
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const projRoot = path.join(__dirname, '..', 'greenshades_backend.node');
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if (fs.existsSync(projRoot)) return projRoot;
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}
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if (!platformKey) return null;
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const prebuild = path.join(__dirname, 'prebuilds', platformKey, 'greenshades_backend.node');
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return fs.existsSync(prebuild) ? prebuild : null;
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}
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function ensureLoaded() {
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if (module.exports.__loaded) return true;
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const candidate = candidatePath();
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if (!candidate) return false;
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const { dlopen } = require('process');
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const constants = process.binding('constants');
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const RTLD_LAZY = constants.os.dlopen.RTLD_LAZY;
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const RTLD_LOCAL = constants.os.dlopen.RTLD_LOCAL;
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try {
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const mod = { exports: {} };
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dlopen(mod, candidate, RTLD_LAZY | RTLD_LOCAL);
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if (typeof mod.exports.createBackend === 'function') {
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for (const k of Object.keys(mod.exports)) {
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module.exports[k] = mod.exports[k];
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}
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module.exports.__loaded = true;
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return true;
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}
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} catch (_) {}
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return false;
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}
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if (!skipNative) {
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const candidate = candidatePath();
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module.exports.__nativeCandidatePath = candidate;
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module.exports.__nativeCandidatePresent = !!candidate;
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module.exports.__nativeAvailable = false;
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module.exports.__loaded = false;
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}
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module.exports.__platformKey = platformKey;
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module.exports.__ensureLoaded = ensureLoaded;
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function notLoadedError() {
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return new Error([
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'Greenshades native addon not available for ' + (platformKey || os.platform() + '-' + os.arch()) + '.',
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'',
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'To build from source:',
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' 1. Install Zig 0.16+',
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' 2. Run: cd zig-native && zig build napi',
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' 3. Copy zig-out/greenshades_backend.node to:',
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' zig-native/node/prebuilds/' + (platformKey || 'YOUR_PLATFORM') + '/greenshades_backend.node',
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].join('\n'));
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}
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const handler = {
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get(target, prop) {
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if (typeof prop === 'string' && prop.startsWith('__')) {
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return target[prop];
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}
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if (typeof prop === 'string' && target[prop] === undefined) {
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if (!ensureLoaded()) throw notLoadedError();
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return target[prop];
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}
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return target[prop];
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},
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};
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module.exports = new Proxy(module.exports, handler);
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