build(broccoli): add tree-differ for diffing broccoli trees

tools/broccoli/tree-differ.ts

@@ -0,0 +1,110 @@
+/// <reference path="../typings/node/node.d.ts" />
+
+import fs = require('fs');
+import path = require('path');
+
+
+export = TreeDiffer;
+
+class TreeDiffer {
+  private fingerprints: {[key: string]: string} = Object.create(null);
+  private nextFingerprints: {[key: string]: string} = Object.create(null);
+  private rootDirName: string;
+
+  constructor(private rootPath: string) { this.rootDirName = path.basename(rootPath); }
+
+
+  public diffTree(): DiffResult {
+    let result = new DiffResult(this.rootDirName);
+    this.dirtyCheckPath(this.rootPath, result);
+    this.detectDeletionsAndUpdateFingerprints(result);
+    result.endTime = Date.now();
+    return result;
+  }
+
+
+  private dirtyCheckPath(rootDir: string, result: DiffResult) {
+    fs.readdirSync(rootDir).forEach((segment) => {
+      let absolutePath = path.join(rootDir, segment);
+      let pathStat = fs.statSync(absolutePath);
+
+      if (pathStat.isDirectory()) {
+        result.directoriesChecked++;
+        this.dirtyCheckPath(absolutePath, result);
+      } else {
+        result.filesChecked++;
+        if (this.isFileDirty(absolutePath, pathStat)) {
+          result.changedPaths.push(path.relative(this.rootPath, absolutePath));
+        }
+      }
+    });
+
+    return result;
+  }
+
+
+  private isFileDirty(path: string, stat: fs.Stats): boolean {
+    let oldFingerprint = this.fingerprints[path];
+    let newFingerprint = `${stat.mtime.getTime()} # ${stat.size}`;
+
+    this.nextFingerprints[path] = newFingerprint;
+
+    if (oldFingerprint) {
+      this.fingerprints[path] = null;
+
+      if (oldFingerprint === newFingerprint) {
+        // nothing changed
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+
+  private detectDeletionsAndUpdateFingerprints(result: DiffResult) {
+    for (let absolutePath in this.fingerprints) {
+      if (this.fingerprints[absolutePath] !== null) {
+        let relativePath = path.relative(this.rootPath, absolutePath);
+        result.removedPaths.push(relativePath);
+      }
+    }
+
+    this.fingerprints = this.nextFingerprints;
+    this.nextFingerprints = Object.create(null);
+  }
+}
+
+
+class DiffResult {
+  public filesChecked: number = 0;
+  public directoriesChecked: number = 0;
+  public changedPaths: string[] = [];
+  public removedPaths: string[] = [];
+  public startTime: number = Date.now();
+  public endTime: number = null;
+
+  constructor(public name: string) {}
+
+  toString() {
+    return `${pad(this.name, 40)}, ` +
+           `duration: ${pad(this.endTime - this.startTime, 5)}ms, ` +
+           `${pad(this.changedPaths.length + this.removedPaths.length, 5)} changes detected ` +
+           `(files: ${pad(this.filesChecked, 5)}, directories: ${pad(this.directoriesChecked, 4)})`;
+  }
+
+  log(verbose) {
+    let prefixedPaths =
+        this.changedPaths.map((p) => `* ${p}`).concat(this.removedPaths.map((p) => `- ${p}`));
+    console.log(`Tree diff: ${this}` +
+                ((verbose && prefixedPaths.length) ? ` [\n  ${prefixedPaths.join('\n  ')}\n]` :  ''));
+  }
+}
+
+
+function pad(value, length) {
+  value = '' + value;
+  let whitespaceLength = (value.length < length) ? length - value.length : 0;
+  whitespaceLength = whitespaceLength + 1;
+  return new Array(whitespaceLength).join(' ') + value;
+}