Media Galleries: Initial media scanner implementation.

chrome/browser/media_galleries/fileapi/media_scanner.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MEDIA_SCANNER_H_

[vandebo (ex-Chrome), 2014/01/29 18:41:45]

I wouldn't put this in fileapi - it's not really part of the fileapi

[Lei Zhang, 2014/01/30 00:29:50]

Done.

+#define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MEDIA_SCANNER_H_
+
+#include <map>
+#include <stack>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/media_galleries/media_scan_types.h"
+
+// MediaScanner scans local hard drives and look for folders that contain
+// media files.
+class MediaScanner {

[vandebo (ex-Chrome), 2014/01/29 18:41:45]

MediaDirectoryFinder ?

[Lei Zhang, 2014/01/30 00:29:50]

Done.

+ public:
+  typedef std::map<base::FilePath, MediaGalleryScanResult> MediaScannerResults;
+  typedef base::Callback<void(bool /*success*/,
+                              const MediaScannerResults& /*results*/)>
+      MediaScannerResultsCallback;
+  typedef base::Callback<MediaGalleryScanFileType(const base::FilePath&)>

[vandebo (ex-Chrome), 2014/01/29 18:41:45]

private ?

[Lei Zhang, 2014/01/30 00:10:49]

Used in (anonymous)::DoScanOnBlockingPool()

+      FilterCallback;
+
+  // Set up a scan with a given set of |roots| as starting points.
+  // The elements of |roots| should not overlap and should be absolute.
+  // Unless the scan gets cancelled, it will call |callback| when the scan
+  // finishes.
+  MediaScanner(const std::vector<base::FilePath>& roots,
+               const MediaScannerResultsCallback& callback);
+  ~MediaScanner();
+
+
+  // Start the scan.
+  void StartScan();
+
+  // Cancel the scan. The MediaScanner should be deleted afterwards.

[vandebo (ex-Chrome), 2014/01/29 18:41:45]

afterwards -> after the callback is called?

[Lei Zhang, 2014/01/30 00:10:49]

CancelScan() does not return until the callback finishes.

Actually, I'll just get rid of CancelScan() altogether. Just delete the object
instead.

+  void CancelScan();
+
+ private:
+  void DoScan();
+  void GotScanResults(const base::FilePath& path,
+                      const std::vector<base::FilePath>* new_folders,

[vandebo (ex-Chrome), 2014/01/29 18:41:45]

nit: arg order, keep path and scan_result together

[Lei Zhang, 2014/01/30 00:10:49]

I don't see why it even matters, but sure.

+                      const MediaGalleryScanResult* scan_result);
+
+  const MediaScannerResultsCallback callback_;
+  MediaScannerResults results_;
+
+  std::stack<base::FilePath> folders_to_scan_;
+  bool started_scan_;
+
+  base::SequencedWorkerPool::SequenceToken token_;
+
+  FilterCallback filter_callback_;
+
+  base::WeakPtrFactory<MediaScanner> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaScanner);
+};
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MEDIA_SCANNER_H_