Media Galleries Partial Deprecation: Remove scan functionality.

chrome/browser/media_galleries/media_scan_manager.cc

Index: chrome/browser/media_galleries/media_scan_manager.cc
diff --git a/chrome/browser/media_galleries/media_scan_manager.cc b/chrome/browser/media_galleries/media_scan_manager.cc
deleted file mode 100644
index 0201cad855b3f4eca470fe215f24266df7b82b8d..0000000000000000000000000000000000000000
--- a/chrome/browser/media_galleries/media_scan_manager.cc
+++ /dev/null
@@ -1,556 +0,0 @@
-// 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_scan_manager.h"
-
-#include <stddef.h>
-
-#include "base/files/file_enumerator.h"
-#include "base/files/file_util.h"
-#include "base/logging.h"
-#include "base/metrics/histogram.h"
-#include "base/time/time.h"
-#include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/media_galleries/media_galleries_preferences.h"
-#include "chrome/browser/media_galleries/media_galleries_preferences_factory.h"
-#include "chrome/browser/media_galleries/media_scan_manager_observer.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/common/extensions/api/media_galleries.h"
-#include "content/public/browser/browser_thread.h"
-#include "extensions/browser/extension_registry.h"
-#include "extensions/browser/extension_system.h"
-#include "extensions/common/extension.h"
-
-using extensions::ExtensionRegistry;
-
-namespace media_galleries = extensions::api::media_galleries;
-
-namespace {
-
-typedef std::set<std::string /*extension id*/> ScanningExtensionIdSet;
-
-// When multiple scan results have the same parent, sometimes it makes sense
-// to combine them into a single scan result at the parent. This constant
-// governs when that happens; kContainerDirectoryMinimumPercent percent of the
-// directories in the parent directory must be scan results.
-const int kContainerDirectoryMinimumPercent = 80;
-
-// How long after a completed media scan can we provide the cached results.
-const int kScanResultsExpiryTimeInHours = 24;
-
-struct LocationInfo {
-  LocationInfo()
-      : pref_id(kInvalidMediaGalleryPrefId),
-        type(MediaGalleryPrefInfo::kInvalidType) {}
-  LocationInfo(MediaGalleryPrefId pref_id, MediaGalleryPrefInfo::Type type,
-               base::FilePath path)
-      : pref_id(pref_id), type(type), path(path) {}
-  // Highest priority comparison by path, next by type (scan result last),
-  // then by pref id (invalid last).
-  bool operator<(const LocationInfo& rhs) const {
-    if (path.value() == rhs.path.value()) {
-      if (type == rhs.type) {
-        return pref_id > rhs.pref_id;
-      }
-      return rhs.type == MediaGalleryPrefInfo::kScanResult;
-    }
-    return path.value() < rhs.path.value();
-  }
-
-  MediaGalleryPrefId pref_id;
-  MediaGalleryPrefInfo::Type type;
-  base::FilePath path;
-  MediaGalleryScanResult file_counts;
-};
-
-// Finds new scan results that are shadowed (the same location, or a child) by
-// existing locations and moves them from |found_folders| to |child_folders|.
-// Also moves new scan results that are shadowed by other new scan results
-// to |child_folders|.
-void PartitionChildScanResults(
-    MediaGalleriesPreferences* preferences,
-    MediaFolderFinder::MediaFolderFinderResults* found_folders,
-    MediaFolderFinder::MediaFolderFinderResults* child_folders) {
-  // Construct a list with everything in it.
-  std::vector<LocationInfo> all_locations;
-  for (MediaFolderFinder::MediaFolderFinderResults::const_iterator it =
-           found_folders->begin(); it != found_folders->end(); ++it) {
-    all_locations.push_back(LocationInfo(kInvalidMediaGalleryPrefId,
-                                         MediaGalleryPrefInfo::kScanResult,
-                                         it->first));
-    all_locations.back().file_counts = it->second;
-  }
-  const MediaGalleriesPrefInfoMap& known_galleries =
-      preferences->known_galleries();
-  for (MediaGalleriesPrefInfoMap::const_iterator it = known_galleries.begin();
-       it != known_galleries.end();
-       ++it) {
-    all_locations.push_back(LocationInfo(it->second.pref_id, it->second.type,
-                                         it->second.AbsolutePath()));
-  }
-  // Sorting on path should put all paths that are prefixes of other paths
-  // next to each other, with the shortest one first.
-  std::sort(all_locations.begin(), all_locations.end());
-
-  size_t previous_parent_index = 0;
-  for (size_t i = 1; i < all_locations.size(); i++) {
-    const LocationInfo& current = all_locations[i];
-    const LocationInfo& previous_parent = all_locations[previous_parent_index];
-    bool is_child = previous_parent.path.IsParent(current.path);
-    if (current.type == MediaGalleryPrefInfo::kScanResult &&
-        current.pref_id == kInvalidMediaGalleryPrefId &&
-        (is_child || previous_parent.path == current.path)) {
-      // Move new scan results that are shadowed.
-      (*child_folders)[current.path] = current.file_counts;
-      found_folders->erase(current.path);
-    } else if (!is_child) {
-      previous_parent_index = i;
-    }
-  }
-}
-
-MediaGalleryScanResult SumFilesUnderPath(
-    const base::FilePath& path,
-    const MediaFolderFinder::MediaFolderFinderResults& candidates) {
-  MediaGalleryScanResult results;
-  for (MediaFolderFinder::MediaFolderFinderResults::const_iterator it =
-           candidates.begin(); it != candidates.end(); ++it) {
-    if (it->first == path || path.IsParent(it->first)) {
-      results.audio_count += it->second.audio_count;
-      results.image_count += it->second.image_count;
-      results.video_count += it->second.video_count;
-    }
-  }
-  return results;
-}
-
-void AddScanResultsForProfile(
-    MediaGalleriesPreferences* preferences,
-    const MediaFolderFinder::MediaFolderFinderResults& found_folders) {
-  // First, remove any existing scan results where no app has been granted
-  // permission - either it is gone, or is already in the new scan results.
-  // This burns some pref ids, but not at an appreciable rate.
-  MediaGalleryPrefIdSet to_remove;
-  const MediaGalleriesPrefInfoMap& known_galleries =
-      preferences->known_galleries();
-  for (MediaGalleriesPrefInfoMap::const_iterator it = known_galleries.begin();
-       it != known_galleries.end();
-       ++it) {
-    if (it->second.type == MediaGalleryPrefInfo::kScanResult &&
-        !preferences->NonAutoGalleryHasPermission(it->first)) {
-      to_remove.insert(it->first);
-    }
-  }
-  for (MediaGalleryPrefIdSet::const_iterator it = to_remove.begin();
-       it != to_remove.end();
-       ++it) {
-    preferences->EraseGalleryById(*it);
-  }
-
-  MediaFolderFinder::MediaFolderFinderResults child_folders;
-  MediaFolderFinder::MediaFolderFinderResults
-      unique_found_folders(found_folders);
-  PartitionChildScanResults(preferences, &unique_found_folders, &child_folders);
-
-  // Updating prefs while iterating them will invalidate the pointer, so
-  // calculate the changes first and then apply them.
-  std::map<MediaGalleryPrefId, MediaGalleryScanResult> to_update;
-  for (MediaGalleriesPrefInfoMap::const_iterator it = known_galleries.begin();
-       it != known_galleries.end();
-       ++it) {
-    const MediaGalleryPrefInfo& gallery = it->second;
-    if (!gallery.IsBlackListedType()) {
-      MediaGalleryScanResult file_counts =
-          SumFilesUnderPath(gallery.AbsolutePath(), child_folders);
-      if (gallery.audio_count != file_counts.audio_count ||
-          gallery.image_count != file_counts.image_count ||
-          gallery.video_count != file_counts.video_count) {
-        to_update[it->first] = file_counts;
-      }
-    }
-  }
-
-  for (std::map<MediaGalleryPrefId,
-                MediaGalleryScanResult>::const_iterator it = to_update.begin();
-       it != to_update.end();
-       ++it) {
-    const MediaGalleryPrefInfo& gallery =
-        preferences->known_galleries().find(it->first)->second;
-      preferences->AddGallery(gallery.device_id, gallery.path, gallery.type,
-                              gallery.volume_label, gallery.vendor_name,
-                              gallery.model_name, gallery.total_size_in_bytes,
-                              gallery.last_attach_time,
-                              it->second.audio_count,
-                              it->second.image_count,
-                              it->second.video_count);
-  }
-
-  // Add new scan results.
-  for (MediaFolderFinder::MediaFolderFinderResults::const_iterator it =
-           unique_found_folders.begin();
-       it != unique_found_folders.end();
-       ++it) {
-    MediaGalleryScanResult file_counts =
-        SumFilesUnderPath(it->first, child_folders);
-    // The top level scan result is not in |child_folders|. Add it in as well.
-    file_counts.audio_count += it->second.audio_count;
-    file_counts.image_count += it->second.image_count;
-    file_counts.video_count += it->second.video_count;
-
-    MediaGalleryPrefInfo gallery;
-    bool existing = preferences->LookUpGalleryByPath(it->first, &gallery);
-    DCHECK(!existing);
-    preferences->AddGallery(gallery.device_id, gallery.path,
-                            MediaGalleryPrefInfo::kScanResult,
-                            gallery.volume_label, gallery.vendor_name,
-                            gallery.model_name, gallery.total_size_in_bytes,
-                            gallery.last_attach_time, file_counts.audio_count,
-                            file_counts.image_count, file_counts.video_count);
-  }
-  UMA_HISTOGRAM_COUNTS_10000("MediaGalleries.ScanGalleriesPopulated",
-                             unique_found_folders.size() + to_update.size());
-}
-
-int CountScanResultsForExtension(MediaGalleriesPreferences* preferences,
-                                 const extensions::Extension* extension,
-                                 MediaGalleryScanResult* file_counts) {
-  int gallery_count = 0;
-
-  MediaGalleryPrefIdSet permitted_galleries =
-      preferences->GalleriesForExtension(*extension);
-  const MediaGalleriesPrefInfoMap& known_galleries =
-      preferences->known_galleries();
-  for (MediaGalleriesPrefInfoMap::const_iterator it = known_galleries.begin();
-       it != known_galleries.end();
-       ++it) {
-    if (it->second.type == MediaGalleryPrefInfo::kScanResult &&
-        !ContainsKey(permitted_galleries, it->first)) {
-      gallery_count++;
-      file_counts->audio_count += it->second.audio_count;
-      file_counts->image_count += it->second.image_count;
-      file_counts->video_count += it->second.video_count;
-    }
-  }
-  return gallery_count;
-}
-
-int CountDirectoryEntries(const base::FilePath& path) {
-  base::FileEnumerator dir_counter(
-      path, false /*recursive*/, base::FileEnumerator::DIRECTORIES);
-  int count = 0;
-  base::FileEnumerator::FileInfo info;
-  for (base::FilePath name = dir_counter.Next(); !name.empty();
-       name = dir_counter.Next()) {
-    if (!base::IsLink(name))
-      ++count;
-  }
-  return count;
-}
-
-struct ContainerCount {
-  int seen_count, entries_count;
-  bool is_qualified;
-
-  ContainerCount() : seen_count(0), entries_count(-1), is_qualified(false) {}
-};
-
-typedef std::map<base::FilePath, ContainerCount> ContainerCandidates;
-
-}  // namespace
-
-MediaScanManager::MediaScanManager()
-    : scoped_extension_registry_observer_(this),
-      weak_factory_(this) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-}
-
-MediaScanManager::~MediaScanManager() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-}
-
-void MediaScanManager::AddObserver(Profile* profile,
-                                   MediaScanManagerObserver* observer) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  DCHECK(!ContainsKey(observers_, profile));
-  observers_[profile].observer = observer;
-}
-
-void MediaScanManager::RemoveObserver(Profile* profile) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  bool scan_in_progress = ScanInProgress();
-  observers_.erase(profile);
-  DCHECK_EQ(scan_in_progress, ScanInProgress());
-}
-
-void MediaScanManager::CancelScansForProfile(Profile* profile) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  observers_[profile].scanning_extensions.clear();
-
-  if (!ScanInProgress())
-    folder_finder_.reset();
-}
-
-void MediaScanManager::StartScan(Profile* profile,
-                                 const extensions::Extension* extension,
-                                 bool user_gesture) {
-  DCHECK(extension);
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-
-  ScanObserverMap::iterator scans_for_profile = observers_.find(profile);
-  // We expect that an MediaScanManagerObserver has already been registered.
-  DCHECK(scans_for_profile != observers_.end());
-  bool scan_in_progress = ScanInProgress();
-  // Ignore requests for extensions that are already scanning.
-  ScanningExtensionIdSet* scanning_extensions;
-  scanning_extensions = &scans_for_profile->second.scanning_extensions;
-  if (scan_in_progress && ContainsKey(*scanning_extensions, extension->id()))
-    return;
-
-  // Provide cached result if there is not already a scan in progress,
-  // there is no user gesture, and the previous results are unexpired.
-  MediaGalleriesPreferences* preferences =
-      MediaGalleriesPreferencesFactory::GetForProfile(profile);
-  base::TimeDelta time_since_last_scan =
-      base::Time::Now() - preferences->GetLastScanCompletionTime();
-  if (!scan_in_progress && !user_gesture && time_since_last_scan <
-          base::TimeDelta::FromHours(kScanResultsExpiryTimeInHours)) {
-    MediaGalleryScanResult file_counts;
-    int gallery_count =
-        CountScanResultsForExtension(preferences, extension, &file_counts);
-    scans_for_profile->second.observer->OnScanStarted(extension->id());
-    scans_for_profile->second.observer->OnScanFinished(extension->id(),
-                                                       gallery_count,
-                                                       file_counts);
-    return;
-  }
-
-  // On first scan for the |profile|, register to listen for extension unload.
-  if (scanning_extensions->empty())
-    scoped_extension_registry_observer_.Add(ExtensionRegistry::Get(profile));
-
-  scanning_extensions->insert(extension->id());
-  scans_for_profile->second.observer->OnScanStarted(extension->id());
-
-  if (folder_finder_)
-    return;
-
-  MediaFolderFinder::MediaFolderFinderResultsCallback callback =
-      base::Bind(&MediaScanManager::OnScanCompleted,
-                 weak_factory_.GetWeakPtr());
-  if (testing_folder_finder_factory_.is_null()) {
-    folder_finder_.reset(new MediaFolderFinder(callback));
-  } else {
-    folder_finder_.reset(testing_folder_finder_factory_.Run(callback));
-  }
-  scan_start_time_ = base::Time::Now();
-  folder_finder_->StartScan();
-}
-
-void MediaScanManager::CancelScan(Profile* profile,
-                                  const extensions::Extension* extension) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-
-  // Erases the logical scan if found, early exit otherwise.
-  ScanObserverMap::iterator scans_for_profile = observers_.find(profile);
-  if (scans_for_profile == observers_.end() ||
-      !scans_for_profile->second.scanning_extensions.erase(extension->id())) {
-    return;
-  }
-
-  scans_for_profile->second.observer->OnScanCancelled(extension->id());
-
-  // No more scanning extensions for |profile|, so stop listening for unloads.
-  if (scans_for_profile->second.scanning_extensions.empty())
-    scoped_extension_registry_observer_.Remove(ExtensionRegistry::Get(profile));
-
-  if (!ScanInProgress()) {
-    folder_finder_.reset();
-    DCHECK(!scan_start_time_.is_null());
-    UMA_HISTOGRAM_LONG_TIMES("MediaGalleries.ScanCancelTime",
-                             base::Time::Now() - scan_start_time_);
-    scan_start_time_ = base::Time();
-  }
-}
-
-void MediaScanManager::SetMediaFolderFinderFactory(
-    const MediaFolderFinderFactory& factory) {
-  testing_folder_finder_factory_ = factory;
-}
-
-// A single directory may contain many folders with media in them, without
-// containing any media itself. In fact, the primary purpose of that directory
-// may be to contain media directories. This function tries to find those
-// container directories.
-MediaFolderFinder::MediaFolderFinderResults
-MediaScanManager::FindContainerScanResults(
-    const MediaFolderFinder::MediaFolderFinderResults& found_folders,
-    const std::vector<base::FilePath>& sensitive_locations) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
-  std::vector<base::FilePath> abs_sensitive_locations;
-  for (size_t i = 0; i < sensitive_locations.size(); ++i) {
-    base::FilePath path = base::MakeAbsoluteFilePath(sensitive_locations[i]);
-    if (!path.empty())
-      abs_sensitive_locations.push_back(path);
-  }
-  // Recursively find parent directories with majority of media directories,
-  // or container directories.
-  // |candidates| keeps track of directories which might have enough
-  // such directories to have us return them.
-  typedef std::map<base::FilePath, ContainerCount> ContainerCandidates;
-  ContainerCandidates candidates;
-  for (MediaFolderFinder::MediaFolderFinderResults::const_iterator it =
-           found_folders.begin();
-       it != found_folders.end();
-       ++it) {
-    base::FilePath child_directory = it->first;
-    base::FilePath parent_directory = child_directory.DirName();
-
-    // Parent of root is root.
-    while (!parent_directory.empty() && child_directory != parent_directory) {
-      // Skip sensitive folders and their ancestors.
-      base::FilePath abs_parent_directory =
-          base::MakeAbsoluteFilePath(parent_directory);
-      if (abs_parent_directory.empty())
-        break;
-      bool is_sensitive = false;
-      for (size_t i = 0; i < abs_sensitive_locations.size(); ++i) {
-        if (abs_parent_directory == abs_sensitive_locations[i] ||
-            abs_parent_directory.IsParent(abs_sensitive_locations[i])) {
-          is_sensitive = true;
-          break;
-        }
-      }
-      if (is_sensitive)
-        break;
-
-      // Don't bother with ones we already have.
-      if (found_folders.find(parent_directory) != found_folders.end())
-        continue;
-
-      ContainerCandidates::iterator parent_it =
-          candidates.find(parent_directory);
-      if (parent_it == candidates.end()) {
-        ContainerCount count;
-        count.seen_count = 1;
-        count.entries_count = CountDirectoryEntries(parent_directory);
-        parent_it =
-            candidates.insert(std::make_pair(parent_directory, count)).first;
-      } else {
-        ++candidates[parent_directory].seen_count;
-      }
-      // If previously sufficient, or not sufficient, bail.
-      if (parent_it->second.is_qualified ||
-          parent_it->second.seen_count * 100 / parent_it->second.entries_count <
-              kContainerDirectoryMinimumPercent) {
-        break;
-      }
-      // Otherwise, mark qualified and check parent.
-      parent_it->second.is_qualified = true;
-      child_directory = parent_directory;
-      parent_directory = child_directory.DirName();
-    }
-  }
-  MediaFolderFinder::MediaFolderFinderResults result;
-  // Copy and return worthy results.
-  for (ContainerCandidates::const_iterator it = candidates.begin();
-       it != candidates.end();
-       ++it) {
-    if (it->second.is_qualified && it->second.seen_count >= 2)
-      result[it->first] = MediaGalleryScanResult();
-  }
-  return result;
-}
-
-MediaScanManager::ScanObservers::ScanObservers() : observer(NULL) {}
-MediaScanManager::ScanObservers::~ScanObservers() {}
-
-void MediaScanManager::OnExtensionUnloaded(
-    content::BrowserContext* browser_context,
-    const extensions::Extension* extension,
-    extensions::UnloadedExtensionInfo::Reason reason) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  CancelScan(Profile::FromBrowserContext(browser_context), extension);
-}
-
-bool MediaScanManager::ScanInProgress() const {
-  for (ScanObserverMap::const_iterator it = observers_.begin();
-       it != observers_.end();
-       ++it) {
-    if (!it->second.scanning_extensions.empty())
-      return true;
-  }
-  return false;
-}
-
-void MediaScanManager::OnScanCompleted(
-    bool success,
-    const MediaFolderFinder::MediaFolderFinderResults& found_folders) {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  if (!folder_finder_ || !success) {
-    folder_finder_.reset();
-    return;
-  }
-
-  UMA_HISTOGRAM_COUNTS_10000("MediaGalleries.ScanDirectoriesFound",
-                             found_folders.size());
-  DCHECK(!scan_start_time_.is_null());
-  UMA_HISTOGRAM_LONG_TIMES("MediaGalleries.ScanFinishedTime",
-                           base::Time::Now() - scan_start_time_);
-  scan_start_time_ = base::Time();
-
-  content::BrowserThread::PostTaskAndReplyWithResult(
-      content::BrowserThread::FILE, FROM_HERE,
-      base::Bind(FindContainerScanResults,
-                 found_folders,
-                 folder_finder_->graylisted_folders()),
-      base::Bind(&MediaScanManager::OnFoundContainerDirectories,
-                 weak_factory_.GetWeakPtr(),
-                 found_folders));
-}
-
-void MediaScanManager::OnFoundContainerDirectories(
-    const MediaFolderFinder::MediaFolderFinderResults& found_folders,
-    const MediaFolderFinder::MediaFolderFinderResults& container_folders) {
-  MediaFolderFinder::MediaFolderFinderResults folders;
-  folders.insert(found_folders.begin(), found_folders.end());
-  folders.insert(container_folders.begin(), container_folders.end());
-
-  for (ScanObserverMap::iterator scans_for_profile = observers_.begin();
-       scans_for_profile != observers_.end();
-       ++scans_for_profile) {
-    if (scans_for_profile->second.scanning_extensions.empty())
-      continue;
-    Profile* profile = scans_for_profile->first;
-    MediaGalleriesPreferences* preferences =
-        MediaGalleriesPreferencesFactory::GetForProfile(profile);
-    ExtensionService* extension_service =
-        extensions::ExtensionSystem::Get(profile)->extension_service();
-    if (!extension_service)
-      continue;
-
-    AddScanResultsForProfile(preferences, folders);
-
-    ScanningExtensionIdSet* scanning_extensions =
-        &scans_for_profile->second.scanning_extensions;
-    for (ScanningExtensionIdSet::const_iterator extension_id_it =
-             scanning_extensions->begin();
-         extension_id_it != scanning_extensions->end();
-         ++extension_id_it) {
-      const extensions::Extension* extension =
-          extension_service->GetExtensionById(*extension_id_it, false);
-      if (extension) {
-        MediaGalleryScanResult file_counts;
-        int gallery_count = CountScanResultsForExtension(preferences, extension,
-                                                         &file_counts);
-        scans_for_profile->second.observer->OnScanFinished(*extension_id_it,
-                                                           gallery_count,
-                                                           file_counts);
-      }
-    }
-    scanning_extensions->clear();
-    preferences->SetLastScanCompletionTime(base::Time::Now());
-  }
-  scoped_extension_registry_observer_.RemoveAll();
-  folder_finder_.reset();
-}