update

ts/watcher_poller.ts

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+
+/* IMPORT */
+
+import {FileType, TargetEvent} from './enums.js';
+import LazyMapSet from './lazy_map_set.js';
+import Utils from './utils.js';
+import WatcherStats from './watcher_stats.js';
+import type {INO, Path} from './types.js';
+
+/* MAIN */
+
+class WatcherPoller {
+
+  /* VARIABLES */
+
+  inos: Partial<Record<TargetEvent, Record<Path, [INO, FileType]>>> = {};
+  paths: LazyMapSet<INO, Path> = new LazyMapSet ();
+  stats: Map<Path, WatcherStats> = new Map ();
+
+  /* API */
+
+  getIno ( targetPath: Path, event: TargetEvent, type?: FileType ): INO | undefined {
+
+    const inos = this.inos[event];
+
+    if ( !inos ) return;
+
+    const ino = inos[targetPath];
+
+    if ( !ino ) return;
+
+    if ( type && ino[1] !== type ) return;
+
+    return ino[0];
+
+  }
+
+  getStats ( targetPath: Path ): WatcherStats | undefined {
+
+    return this.stats.get ( targetPath );
+
+  }
+
+  async poll ( targetPath: Path, timeout?: number ): Promise<WatcherStats | undefined> {
+
+    const stats = await Utils.fs.poll ( targetPath, timeout );
+
+    if ( !stats ) return;
+
+    const isSupported = stats.isFile () || stats.isDirectory ();
+
+    if ( !isSupported ) return;
+
+    return new WatcherStats ( stats );
+
+  }
+
+  reset (): void {
+
+    this.inos = {};
+    this.paths = new LazyMapSet ();
+    this.stats = new Map ();
+
+  }
+
+  async update ( targetPath: Path, timeout?: number ): Promise<TargetEvent[]> {
+
+    const prev = this.getStats ( targetPath );
+    const next = await this.poll ( targetPath, timeout );
+
+    this.updateStats ( targetPath, next );
+
+    if ( !prev && next ) {
+
+      if ( next.isFile () ) {
+
+        this.updateIno ( targetPath, TargetEvent.ADD, next );
+
+        return [TargetEvent.ADD];
+
+      }
+
+      if ( next.isDirectory () ) {
+
+        this.updateIno ( targetPath, TargetEvent.ADD_DIR, next );
+
+        return [TargetEvent.ADD_DIR];
+
+      }
+
+    } else if ( prev && !next ) {
+
+      if ( prev.isFile () ) {
+
+        this.updateIno ( targetPath, TargetEvent.UNLINK, prev );
+
+        return [TargetEvent.UNLINK];
+
+      }
+
+      if ( prev.isDirectory () ) {
+
+        this.updateIno ( targetPath, TargetEvent.UNLINK_DIR, prev );
+
+        return [TargetEvent.UNLINK_DIR];
+
+      }
+
+    } else if ( prev && next ) {
+
+      if ( prev.isFile () ) {
+
+        if ( next.isFile () ) {
+
+          if ( prev.ino === next.ino && !prev.size && !next.size ) return []; // Same path, same content and same file, nothing actually changed
+
+          this.updateIno ( targetPath, TargetEvent.CHANGE, next );
+
+          return [TargetEvent.CHANGE];
+
+        }
+
+        if ( next.isDirectory () ) {
+
+          this.updateIno ( targetPath, TargetEvent.UNLINK, prev );
+          this.updateIno ( targetPath, TargetEvent.ADD_DIR, next );
+
+          return [TargetEvent.UNLINK, TargetEvent.ADD_DIR];
+
+        }
+
+      } else if ( prev.isDirectory () ) {
+
+        if ( next.isFile () ) {
+
+          this.updateIno ( targetPath, TargetEvent.UNLINK_DIR, prev );
+          this.updateIno ( targetPath, TargetEvent.ADD, next );
+
+          return [TargetEvent.UNLINK_DIR, TargetEvent.ADD];
+
+        }
+
+        if ( next.isDirectory () ) {
+
+          if ( prev.ino === next.ino ) return []; // Same path and same directory, nothing actually changed
+
+          this.updateIno ( targetPath, TargetEvent.UNLINK_DIR, prev );
+          this.updateIno ( targetPath, TargetEvent.ADD_DIR, next );
+
+          return [TargetEvent.UNLINK_DIR, TargetEvent.ADD_DIR];
+
+        }
+
+      }
+
+    }
+
+    return [];
+
+  }
+
+  updateIno ( targetPath: Path, event: TargetEvent, stats: WatcherStats ): void {
+
+    const inos = this.inos[event] = this.inos[event] || ( this.inos[event] = {} );
+    const type = stats.isFile () ? FileType.FILE : FileType.DIR;
+
+    inos[targetPath] = [stats.ino, type];
+
+  }
+
+  updateStats ( targetPath: Path, stats?: WatcherStats ): void {
+
+    if ( stats ) {
+
+      this.paths.set ( stats.ino, targetPath );
+      this.stats.set ( targetPath, stats );
+
+    } else {
+
+      const ino = this.stats.get ( targetPath )?.ino || -1;
+
+      this.paths.delete ( ino, targetPath );
+      this.stats.delete ( targetPath );
+
+    }
+
+  }
+
+}
+
+/* EXPORT */
+
+export default WatcherPoller;