Merge pull request #136 from gadget-inc/watcher

Switch to watcher from chokidar for better performance

package.json

@@ -41,14 +41,14 @@
   "dependencies": {
     "@swc/core": "^1.7.28",
     "@swc/helpers": "^0.5.13",
-    "chokidar": "^3.6.0",
     "find-root": "^1.1.0",
     "find-yarn-workspace-root": "^2.0.0",
     "fs-extra": "^11.2.0",
     "globby": "^11.1.0",
     "lodash": "^4.17.20",
     "oxc-resolver": "^1.12.0",
     "pkg-dir": "^5.0.0",
+    "watcher": "^2.3.1",
     "write-file-atomic": "^6.0.0",
     "yargs": "^16.2.0"
   },

spec/PathTrie.spec.ts

@@ -0,0 +1,24 @@
+import { describe, expect, it } from "vitest";
+import { PathTrie } from "../src/PathTrie.js";
+
+describe("PathTrie", () => {
+  it("should insert and search for paths", () => {
+    const trie = new PathTrie();
+    trie.insert("foo/bar");
+    expect(trie.contains("foo/bar")).toBe(true);
+    expect(trie.contains("foo/baz")).toBe(false);
+  });
+
+  it("should check if any paths in the trie start with a given prefix", () => {
+    const trie = new PathTrie();
+    trie.insert("foo/bar");
+    trie.insert("foo/baz");
+    trie.insert("foo/qux/corge");
+    expect(trie.anyStartsWith("foo")).toBe(true);
+    expect(trie.anyStartsWith("foo/bar")).toBe(true);
+    expect(trie.anyStartsWith("foo/corge")).toBe(false);
+    expect(trie.anyStartsWith("qux")).toBe(false);
+    expect(trie.anyStartsWith("foo/qux")).toBe(true);
+    expect(trie.anyStartsWith("foo/qux/corge")).toBe(true);
+  });
+});

src/PathTrie.ts

@@ -0,0 +1,58 @@
+class TrieNode {
+  children: Record<string, TrieNode> = {};
+  isEndOfWord = false;
+}
+
+/**
+ * Prefix matching datastructure for holding paths and seeing if any match a given incoming path
+ **/
+export class PathTrie {
+  root = new TrieNode();
+  seen = new Set<string>();
+
+  insert(path: string) {
+    if (this.seen.has(path)) {
+      return;
+    }
+    let node = this.root;
+    const segments = path.split("/");
+    for (const segment of segments) {
+      if (!node.children[segment]) {
+        node.children[segment] = new TrieNode();
+      }
+      node = node.children[segment];
+    }
+    this.seen.add(path);
+    node.isEndOfWord = true;
+  }
+
+  /**
+   * Has the incoming path been inserted into the trie?
+   */
+  contains(path: string) {
+    let node = this.root;
+    const segments = path.split("/");
+    for (const segment of segments) {
+      if (!node.children[segment]) {
+        return false;
+      }
+      node = node.children[segment];
+    }
+    return node.isEndOfWord;
+  }
+
+  /**
+   * Do any paths in the trie start with the given prefix?
+   */
+  anyStartsWith(prefix: string) {
+    let node = this.root;
+    const segments = prefix.split("/");
+    for (const segment of segments) {
+      if (!node.children[segment]) {
+        return false;
+      }
+      node = node.children[segment];
+    }
+    return true;
+  }
+}

src/Project.ts

@@ -1,7 +1,7 @@
-import type { FSWatcher } from "chokidar";
 import _ from "lodash";
 import type { Compiler } from "./Compiler.js";
 import type { ProjectConfig } from "./Options.js";
+import { PathTrie } from "./PathTrie.js";
 import type { Supervisor } from "./Supervisor.js";
 import { log } from "./utils.js";
 
@@ -15,7 +15,7 @@ export class Project {
   cleanups: (() => void)[] = [];
   currentBatch: ReloadBatch = { paths: [], invalidate: false };
   supervisor!: Supervisor;
-  watcher?: FSWatcher;
+  watched = new PathTrie();
 
   constructor(readonly workspaceRoot: string, readonly config: ProjectConfig, readonly compiler: Compiler) {}
 
@@ -24,10 +24,13 @@ export class Project {
   }
 
   enqueueReload(path: string, requiresInvalidation = false) {
-    this.compiler.invalidate(path);
-    this.currentBatch.paths.push(path);
-    this.currentBatch.invalidate = this.currentBatch.invalidate || requiresInvalidation;
-    this.debouncedReload();
+    log.debug({ path }, "watch event");
+    if (this.watched.contains(path)) {
+      this.compiler.invalidate(path);
+      this.currentBatch.paths.push(path);
+      this.currentBatch.invalidate = this.currentBatch.invalidate || requiresInvalidation;
+      this.debouncedReload();
+    }
   }
 
   debouncedReload = _.debounce(() => {
@@ -65,4 +68,8 @@ export class Project {
     }
     process.exit(code);
   }
+
+  watchFile(path: string) {
+    this.watched.insert(path);
+  }
 }