Media Galleries: Prune uninteresting folders when scanning.

chrome/browser/media_galleries/media_folder_finder.cc

 // 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.
 
 #include "chrome/browser/media_galleries/media_folder_finder.h"
 
 #include <algorithm>
 #include <set>
 
 #include "base/files/file_enumerator.h"
 #include "base/path_service.h"
 #include "base/sequence_checker.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/task_runner_util.h"
 #include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "chrome/browser/media_galleries/fileapi/media_path_filter.h"
 #include "components/storage_monitor/storage_monitor.h"
 #include "content/public/browser/browser_thread.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/common/chrome_paths.h"
 #include "chromeos/dbus/cros_disks_client.h"
 #endif
 
 typedef base::Callback<void(const std::vector<base::FilePath>& /*roots*/)>
     DefaultScanRootsCallback;
 using content::BrowserThread;
 
 namespace {
 
 const int64 kMinimumImageSize = 200 * 1024;    // 200 KB
 const int64 kMinimumAudioSize = 500 * 1024;    // 500 KB
 const int64 kMinimumVideoSize = 1024 * 1024;   // 1 MB
 
+const int kPrunedPaths[] = {
+  base::DIR_CACHE,
+  base::DIR_TEMP,

[vandebo (ex-Chrome), 2014/02/20 23:00:23]

It's not clear that we want to prune the temp dir... probably, but not clear. 
What do you think?

[Lei Zhang, 2014/02/20 23:04:52]

On Windows, it's buried and not easily accessible for the average user. I doubt
there's anything of value in there. Though it does tend to get crufty with lots
of old temp files.

+#if defined(OS_WIN)
+  base::DIR_IE_INTERNET_CACHE,
+  base::DIR_PROGRAM_FILES,
+  base::DIR_PROGRAM_FILESX86,
+  base::DIR_WINDOWS,
+#endif
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  DIR_USER_LIBRARY,
+#endif
+};
+
 bool IsValidScanPath(const base::FilePath& path) {
   return !path.empty() && path.IsAbsolute();
 }
 
 void CountScanResult(MediaGalleryScanFileType type,
                      MediaGalleryScanResult* scan_result) {
   if (type & MEDIA_GALLERY_SCAN_FILE_TYPE_IMAGE)
     scan_result->image_count += 1;
   if (type & MEDIA_GALLERY_SCAN_FILE_TYPE_AUDIO)
     scan_result->audio_count += 1;
@@ skipping 93 matching lines @@
 }  // namespace
 
 MediaFolderFinder::WorkerReply::WorkerReply() {}
 
 MediaFolderFinder::WorkerReply::~WorkerReply() {}
 
 // The Worker is created on the UI thread, but does all its work on a blocking
 // SequencedTaskRunner.
 class MediaFolderFinder::Worker {
  public:
-  Worker();
+  explicit Worker(const std::vector<base::FilePath>& graylisted_folders);
   ~Worker();
 
   // Scans |path| and return the results.
   WorkerReply ScanFolder(const base::FilePath& path);
 
  private:
+  const std::vector<base::FilePath> graylisted_folders_;
+  std::vector<base::FilePath> pruned_folders_;
+
   scoped_ptr<MediaPathFilter> filter_;
 
   base::SequenceChecker sequence_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(Worker);
 };
 
-MediaFolderFinder::Worker::Worker() {
+MediaFolderFinder::Worker::Worker(
+    const std::vector<base::FilePath>& graylisted_folders)
+    : graylisted_folders_(graylisted_folders),
+      filter_(new MediaPathFilter) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  filter_.reset(new MediaPathFilter);
+
+  for (size_t i = 0; i < arraysize(kPrunedPaths); ++i) {
+    base::FilePath path;
+    if (PathService::Get(kPrunedPaths[i], &path))
+      pruned_folders_.push_back(path);
+  }
+
   sequence_checker_.DetachFromSequence();
 }
 
 MediaFolderFinder::Worker::~Worker() {
   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
 }
 
 MediaFolderFinder::WorkerReply MediaFolderFinder::Worker::ScanFolder(
     const base::FilePath& path) {
   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
   CHECK(IsValidScanPath(path));
 
   WorkerReply reply;
   bool folder_meets_size_requirement = false;
+  bool is_graylisted_folder = false;
+  for (size_t i = 0; i < graylisted_folders_.size(); ++i) {
+    if (path == graylisted_folders_[i] ||
+        path.IsParent(graylisted_folders_[i])) {
+      is_graylisted_folder = true;
+      break;
+    }
+  }
+
   base::FileEnumerator enumerator(
       path,
       false, /* recursive? */
       base::FileEnumerator::FILES | base::FileEnumerator::DIRECTORIES
 #if defined(OS_POSIX)
       | base::FileEnumerator::SHOW_SYM_LINKS  // show symlinks, not follow.
 #endif
-      );
+      );  // NOLINT
   while (!enumerator.Next().empty()) {
     base::FileEnumerator::FileInfo file_info = enumerator.GetInfo();
     base::FilePath full_path = path.Append(file_info.GetName());
     if (MediaPathFilter::ShouldSkip(full_path))
       continue;
 
+    // * Enumerating a directory.

[vandebo (ex-Chrome), 2014/02/20 23:00:23]

nit: remove *

     if (file_info.IsDirectory()) {
-      reply.new_folders.push_back(full_path);
+      bool is_pruned_folder = false;
+      for (size_t i = 0; i < pruned_folders_.size(); ++i) {
+        if (full_path == pruned_folders_[i]) {
+          is_pruned_folder = true;
+          break;
+        }
+      }
+
+      if (!is_pruned_folder)
+        reply.new_folders.push_back(full_path);
       continue;
     }
+
+    // * Enumerating a file.

[vandebo (ex-Chrome), 2014/02/20 23:00:23]

ditto

+    // Do not include scan results for graylisted folders.
+    if (is_graylisted_folder)
+      continue;
+
     MediaGalleryScanFileType type = filter_->GetType(full_path);
     if (type == MEDIA_GALLERY_SCAN_FILE_TYPE_UNKNOWN)
       continue;
 
     CountScanResult(type, &reply.scan_result);
     if (!folder_meets_size_requirement) {
       folder_meets_size_requirement =
           FileMeetsSizeRequirement(type, file_info.GetSize());
     }
   }
   // Make sure there is at least 1 file above a size threshold.
   if (!folder_meets_size_requirement)
     reply.scan_result = MediaGalleryScanResult();
   return reply;
 }
 
 MediaFolderFinder::MediaFolderFinder(
     const MediaFolderFinderResultsCallback& callback)
     : results_callback_(callback),
+      graylisted_folders_(
+          extensions::file_system_api::GetGrayListedDirectories()),
       scan_state_(SCAN_STATE_NOT_STARTED),
-      worker_(new Worker()),
+      worker_(new Worker(graylisted_folders_)),
       has_roots_for_testing_(false),
       weak_factory_(this) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   base::SequencedWorkerPool* pool = BrowserThread::GetBlockingPool();
   worker_task_runner_ = pool->GetSequencedTaskRunner(pool->GetSequenceToken());
 }
 
 MediaFolderFinder::~MediaFolderFinder() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   worker_task_runner_->DeleteSoon(FROM_HERE, worker_);
 
   if (scan_state_ == SCAN_STATE_FINISHED)
     return;
 
   MediaFolderFinderResults empty_results;
-  results_callback_.Run(false /* success? */, empty_results);
+  std::vector<base::FilePath> empty_sensitive_locations;
+  results_callback_.Run(false /* success? */,
+                        empty_results,
+                        empty_sensitive_locations);
 }
 
 void MediaFolderFinder::StartScan() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   if (scan_state_ != SCAN_STATE_NOT_STARTED)
     return;
 
   scan_state_ = SCAN_STATE_STARTED;
   GetDefaultScanRoots(
@@ skipping 50 matching lines @@
             std::back_inserter(folders_to_scan_));
   ScanFolder();
 }
 
 void MediaFolderFinder::ScanFolder() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK_EQ(SCAN_STATE_STARTED, scan_state_);
 
   if (folders_to_scan_.empty()) {
     scan_state_ = SCAN_STATE_FINISHED;
-    results_callback_.Run(true /* success? */, results_);
+    results_callback_.Run(true /* success? */, results_, graylisted_folders_);
     return;
   }
 
   base::FilePath folder_to_scan = folders_to_scan_.back();
   folders_to_scan_.pop_back();
   base::PostTaskAndReplyWithResult(
       worker_task_runner_, FROM_HERE,
       base::Bind(&Worker::ScanFolder,
                  base::Unretained(worker_),
                  folder_to_scan),
@@ skipping 11 matching lines @@
 
   if (!IsEmptyScanResult(reply.scan_result))
     results_[path] = reply.scan_result;
 
   // Push new folders to the |folders_to_scan_| in reverse order.
   std::copy(reply.new_folders.rbegin(), reply.new_folders.rend(),
             std::back_inserter(folders_to_scan_));
 
   ScanFolder();
 }