Add wasm backend (#150)

.github/workflows/release.yml

@@ -97,11 +97,31 @@ jobs:
           name: prebuilds
           path: prebuilds
 
+  build-wasm:
+    runs-on: ubuntu-latest
+    container:
+      image: emscripten/emsdk
+    steps:
+      - uses: actions/checkout@v3
+      - run: corepack enable
+      - uses: actions/setup-node@v3
+        with:
+          cache: yarn
+          node-version: 18
+      - run: yarn --frozen-lockfile
+      - run: make wasm
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v3
+        with:
+          name: wasm
+          path: build/Release/watcher.wasm
+
   release:
     runs-on: ubuntu-latest
     needs:
       - build
       - build-freebsd
+      - build-wasm
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
@@ -111,7 +131,9 @@ jobs:
       - name: Download artifacts
         uses: actions/download-artifact@v3
       - name: Build npm packages
-        run: node scripts/build-npm.js
+        run: |
+          node scripts/build-npm.js
+          node scripts/build-wasm.js
       - name: Publish to npm
         env:
           NPM_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/test.yml

@@ -3,7 +3,6 @@ on:
   push:
     branches: [master]
   pull_request:
-    branches: [master]
 
 jobs:
   test:
@@ -51,6 +50,7 @@ jobs:
           watchman -v
       - run: yarn --frozen-lockfile
       - run: yarn test
+
   test-freebsd:
     runs-on: macos-latest
     steps:
@@ -68,3 +68,18 @@ jobs:
           run: |
             yarn --frozen-lockfile
             yarn test
+
+  test-wasm:
+    runs-on: ubuntu-latest
+    container:
+      image: emscripten/emsdk
+    steps:
+      - uses: actions/checkout@v3
+      - run: corepack enable
+      - uses: actions/setup-node@v3
+        with:
+          cache: yarn
+          node-version: 18
+      - run: yarn --frozen-lockfile
+      - run: make wasm-debug
+      - run: TEST_WASM=1 yarn test

Makefile

@@ -0,0 +1,37 @@
+NODE_PATH := $(dir $(shell which node))
+HEADERS_URL := $(shell node -p "process.release.headersUrl")
+NODE_VERSION := $(shell node -p "process.version")
+
+INCS_Debug := \
+	-Ibuild/node-$(NODE_VERSION)/include/node \
+	-I$(shell node -p "require('node-addon-api').include_dir")
+
+SRC := src/binding.cc src/Watcher.cc src/Backend.cc src/DirTree.cc src/Glob.cc src/Debounce.cc src/shared/BruteForceBackend.cc src/unix/legacy.cc src/wasm/WasmBackend.cc
+FLAGS := $(INCS_Debug) \
+	-Oz \
+	-flto \
+	-fwasm-exceptions \
+	-DNAPI_HAS_THREADS=1 \
+	-sEXPORTED_FUNCTIONS="['_napi_register_wasm_v1', '_wasm_backend_event_handler', '_malloc', '_free', '_on_timeout']" \
+	-sERROR_ON_UNDEFINED_SYMBOLS=0 \
+	-s INITIAL_MEMORY=524288000
+
+build/node-headers.tar.gz:
+	curl $(HEADERS_URL) -o build/node-headers.tar.gz
+
+build/node-$(NODE_VERSION): build/node-headers.tar.gz
+	tar -xvf build/node-headers.tar.gz -C build
+	touch build/node-$(NODE_VERSION)
+
+build/Release/watcher.wasm: build/node-$(NODE_VERSION) $(SRC)
+	mkdir -p build/Release
+	em++ $(FLAGS) -sDECLARE_ASM_MODULE_EXPORTS=0 -o build/Release/watcher.js $(SRC)
+
+build/Debug/watcher.wasm: build/node-$(NODE_VERSION) $(SRC)
+	mkdir -p build/Debug
+	em++ -g $(FLAGS) -o build/Debug/watcher.js $(SRC)
+
+wasm: build/Release/watcher.wasm
+wasm-debug: build/Debug/watcher.wasm
+
+.PHONY: wasm wasm-debug

binding.gyp

@@ -3,7 +3,7 @@
     {
       "target_name": "watcher",
       "defines": [ "NAPI_DISABLE_CPP_EXCEPTIONS" ],
-      "sources": [ "src/binding.cc", "src/Watcher.cc", "src/Backend.cc", "src/DirTree.cc", "src/Glob.cc" ],
+      "sources": [ "src/binding.cc", "src/Watcher.cc", "src/Backend.cc", "src/DirTree.cc", "src/Glob.cc", "src/Debounce.cc" ],
       "include_dirs" : ["<!(node -p \"require('node-addon-api').include_dir\")"],
       'cflags!': [ '-fno-exceptions' ],
       'cflags_cc!': [ '-fno-exceptions' ],

index.js

@@ -1,6 +1,4 @@
-const path = require('path');
-const micromatch = require('micromatch');
-const isGlob = require('is-glob');
+const {createWrapper} = require('./wrapper');
 
 let name = `@parcel/watcher-${process.platform}-${process.arch}`;
 if (process.platform === 'linux') {
@@ -64,38 +62,8 @@ function normalizeOptions(dir, opts = {}) {
   return opts;
 }
 
-exports.writeSnapshot = (dir, snapshot, opts) => {
-  return binding.writeSnapshot(
-    path.resolve(dir),
-    path.resolve(snapshot),
-    normalizeOptions(dir, opts),
-  );
-};
-
-exports.getEventsSince = (dir, snapshot, opts) => {
-  return binding.getEventsSince(
-    path.resolve(dir),
-    path.resolve(snapshot),
-    normalizeOptions(dir, opts),
-  );
-};
-
-exports.subscribe = async (dir, fn, opts) => {
-  dir = path.resolve(dir);
-  opts = normalizeOptions(dir, opts);
-  await binding.subscribe(dir, fn, opts);
-
-  return {
-    unsubscribe() {
-      return binding.unsubscribe(dir, fn, opts);
-    },
-  };
-};
-
-exports.unsubscribe = (dir, fn, opts) => {
-  return binding.unsubscribe(
-    path.resolve(dir),
-    fn,
-    normalizeOptions(dir, opts),
-  );
-};
+const wrapper = createWrapper(binding);
+exports.writeSnapshot = wrapper.writeSnapshot;
+exports.getEventsSince = wrapper.getEventsSince;
+exports.subscribe = wrapper.subscribe;
+exports.unsubscribe = wrapper.unsubscribe;

package.json

@@ -54,6 +54,7 @@
     "husky": "^7.0.2",
     "lint-staged": "^11.1.2",
     "mocha": "^9.1.1",
+    "napi-wasm": "^1.1.0",
     "prebuildify": "^5.0.1",
     "prettier": "^2.3.2"
   },

scripts/build-wasm.js

@@ -0,0 +1,49 @@
+const exec = require('child_process').execSync;
+const fs = require('fs');
+const pkg = require('../package.json');
+
+const dir = `${__dirname}/..`;
+try {
+  fs.mkdirSync(dir + '/npm/wasm');
+} catch (err) { }
+
+let dts = fs.readFileSync(`${dir}/index.d.ts`, 'utf8');
+dts += `
+/** Initializes the web assembly module. */
+export default function init(input?: string | URL | Request): Promise<void>;
+`;
+fs.writeFileSync(`${dir}/npm/wasm/index.d.ts`, dts);
+
+let readme = fs.readFileSync(`${dir}/README.md`, 'utf8');
+readme = readme.replace('# ⚡️ Lightning CSS', '# ⚡️ lightningcss-wasm');
+fs.writeFileSync(`${dir}/npm/wasm/README.md`, readme);
+
+let js = fs.readFileSync(`${dir}/wasm/index.mjs`, 'utf8');
+js = js.replace('../build/Debug/watcher.wasm', 'watcher.wasm');
+js = js.replace('../wrapper.js', './wrapper.js');
+fs.writeFileSync(`${dir}/npm/wasm/index.mjs`, js);
+
+fs.copyFileSync(`${dir}/wrapper.js`, `${dir}/npm/wasm/wrapper.js`);
+fs.copyFileSync(`${dir}/wasm/watcher.wasm`, `${dir}/npm/wasm/watcher.wasm`);
+
+let wasmPkg = { ...pkg };
+wasmPkg.name = '@parcel/watcher-wasm';
+wasmPkg.main = 'index.mjs';
+wasmPkg.module = 'index.mjs';
+wasmPkg.types = 'index.d.ts';
+wasmPkg.sideEffects = false;
+wasmPkg.files = ['*.js', '*.mjs', '*.d.ts', '*.wasm'];
+wasmPkg.dependencies = {
+  'napi-wasm': pkg.devDependencies['napi-wasm'],
+  'is-glob': pkg.dependencies['is-glob'],
+  'micromatch': pkg.dependencies['micromatch']
+};
+delete wasmPkg.exports;
+delete wasmPkg.binary;
+delete wasmPkg['lint-staged'];
+delete wasmPkg.husky;
+delete wasmPkg.devDependencies;
+delete wasmPkg.optionalDependencies;
+delete wasmPkg.targets;
+delete wasmPkg.scripts;
+fs.writeFileSync(`${dir}/npm/wasm/package.json`, JSON.stringify(wasmPkg, false, 2) + '\n');

src/Backend.cc

@@ -13,6 +13,9 @@
 #ifdef KQUEUE
 #include "kqueue/KqueueBackend.hh"
 #endif
+#ifdef __wasm32__
+#include "wasm/WasmBackend.hh"
+#endif
 #include "shared/BruteForceBackend.hh"
 
 #include "Backend.hh"
@@ -49,6 +52,11 @@ std::shared_ptr<Backend> getBackend(std::string backend) {
       return std::make_shared<KqueueBackend>();
     }
   #endif
+  #ifdef __wasm32__
+    if (backend == "wasm" || backend == "default") {
+      return std::make_shared<WasmBackend>();
+    }
+  #endif
   if (backend == "brute-force" || backend == "default") {
     return std::make_shared<BruteForceBackend>();
   }
@@ -79,20 +87,33 @@ void removeShared(Backend *backend) {
       break;
     }
   }
+
+  // Free up memory.
+  if (sharedBackends.size() == 0) {
+    sharedBackends.rehash(0);
+  }
 }
 
 void Backend::run() {
-  mThread = std::thread([this] () {
+  #ifndef __wasm32__
+    mThread = std::thread([this] () {
+      try {
+        start();
+      } catch (std::exception &err) {
+        handleError(err);
+      }
+    });
+
+    if (mThread.joinable()) {
+      mStartedSignal.wait();
+    }
+  #else
     try {
       start();
     } catch (std::exception &err) {
       handleError(err);
     }
-  });
-
-  if (mThread.joinable()) {
-    mStartedSignal.wait();
-  }
+  #endif
 }
 
 void Backend::notifyStarted() {
@@ -104,15 +125,17 @@ void Backend::start() {
 }
 
 Backend::~Backend() {
-  // Wait for thread to stop
-  if (mThread.joinable()) {
-    // If the backend is being destroyed from the thread itself, detach, otherwise join.
-    if (mThread.get_id() == std::this_thread::get_id()) {
-      mThread.detach();
-    } else {
-      mThread.join();
+  #ifndef __wasm32__
+    // Wait for thread to stop
+    if (mThread.joinable()) {
+      // If the backend is being destroyed from the thread itself, detach, otherwise join.
+      if (mThread.get_id() == std::this_thread::get_id()) {
+        mThread.detach();
+      } else {
+        mThread.join();
+      }
     }
-  }
+  #endif
 }
 
 void Backend::watch(Watcher &watcher) {