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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "apps/saved_files_service.h"
      6 
      7 #include <algorithm>
      8 
      9 #include "apps/saved_files_service_factory.h"
     10 #include "base/basictypes.h"
     11 #include "base/containers/hash_tables.h"
     12 #include "base/value_conversions.h"
     13 #include "chrome/browser/chrome_notification_types.h"
     14 #include "chrome/browser/extensions/extension_host.h"
     15 #include "chrome/browser/extensions/extension_prefs.h"
     16 #include "chrome/browser/extensions/extension_service.h"
     17 #include "chrome/browser/extensions/extension_system.h"
     18 #include "chrome/browser/profiles/profile.h"
     19 #include "content/public/browser/notification_service.h"
     20 #include "extensions/common/permissions/api_permission.h"
     21 #include "extensions/common/permissions/permission_set.h"
     22 
     23 namespace apps {
     24 
     25 using extensions::APIPermission;
     26 using extensions::Extension;
     27 using extensions::ExtensionHost;
     28 using extensions::ExtensionPrefs;
     29 
     30 namespace {
     31 
     32 // Preference keys
     33 
     34 // The file entries that the app has permission to access.
     35 const char kFileEntries[] = "file_entries";
     36 
     37 // The path to a file entry that the app had permission to access.
     38 const char kFileEntryPath[] = "path";
     39 
     40 // Whether or not the the entry refers to a directory.
     41 const char kFileEntryIsDirectory[] = "is_directory";
     42 
     43 // The sequence number in the LRU of the file entry.
     44 const char kFileEntrySequenceNumber[] = "sequence_number";
     45 
     46 const size_t kMaxSavedFileEntries = 500;
     47 const int kMaxSequenceNumber = kint32max;
     48 
     49 // These might be different to the constant values in tests.
     50 size_t g_max_saved_file_entries = kMaxSavedFileEntries;
     51 int g_max_sequence_number = kMaxSequenceNumber;
     52 
     53 // Persists a SavedFileEntry in ExtensionPrefs.
     54 void AddSavedFileEntry(ExtensionPrefs* prefs,
     55                        const std::string& extension_id,
     56                        const SavedFileEntry& file_entry) {
     57   ExtensionPrefs::ScopedDictionaryUpdate update(
     58       prefs, extension_id, kFileEntries);
     59   DictionaryValue* file_entries = update.Get();
     60   if (!file_entries)
     61     file_entries = update.Create();
     62   DCHECK(!file_entries->GetDictionaryWithoutPathExpansion(file_entry.id, NULL));
     63 
     64   DictionaryValue* file_entry_dict = new DictionaryValue();
     65   file_entry_dict->Set(kFileEntryPath, CreateFilePathValue(file_entry.path));
     66   file_entry_dict->SetBoolean(kFileEntryIsDirectory, file_entry.is_directory);
     67   file_entry_dict->SetInteger(kFileEntrySequenceNumber,
     68                               file_entry.sequence_number);
     69   file_entries->SetWithoutPathExpansion(file_entry.id, file_entry_dict);
     70 }
     71 
     72 // Updates the sequence_number of a SavedFileEntry persisted in ExtensionPrefs.
     73 void UpdateSavedFileEntry(ExtensionPrefs* prefs,
     74                           const std::string& extension_id,
     75                           const SavedFileEntry& file_entry) {
     76   ExtensionPrefs::ScopedDictionaryUpdate update(
     77       prefs, extension_id, kFileEntries);
     78   DictionaryValue* file_entries = update.Get();
     79   DCHECK(file_entries);
     80   DictionaryValue* file_entry_dict = NULL;
     81   file_entries->GetDictionaryWithoutPathExpansion(file_entry.id,
     82                                                   &file_entry_dict);
     83   DCHECK(file_entry_dict);
     84   file_entry_dict->SetInteger(kFileEntrySequenceNumber,
     85                               file_entry.sequence_number);
     86 }
     87 
     88 // Removes a SavedFileEntry from ExtensionPrefs.
     89 void RemoveSavedFileEntry(ExtensionPrefs* prefs,
     90                           const std::string& extension_id,
     91                           const std::string& file_entry_id) {
     92   ExtensionPrefs::ScopedDictionaryUpdate update(
     93       prefs, extension_id, kFileEntries);
     94   DictionaryValue* file_entries = update.Get();
     95   if (!file_entries)
     96     file_entries = update.Create();
     97   file_entries->RemoveWithoutPathExpansion(file_entry_id, NULL);
     98 }
     99 
    100 // Clears all SavedFileEntry for the app from ExtensionPrefs.
    101 void ClearSavedFileEntries(ExtensionPrefs* prefs,
    102                            const std::string& extension_id) {
    103   prefs->UpdateExtensionPref(extension_id, kFileEntries, NULL);
    104 }
    105 
    106 // Returns all SavedFileEntries for the app.
    107 std::vector<SavedFileEntry> GetSavedFileEntries(
    108     ExtensionPrefs* prefs,
    109     const std::string& extension_id) {
    110   std::vector<SavedFileEntry> result;
    111   const DictionaryValue* file_entries = NULL;
    112   if (!prefs->ReadPrefAsDictionary(extension_id, kFileEntries, &file_entries))
    113     return result;
    114 
    115   for (DictionaryValue::Iterator it(*file_entries); !it.IsAtEnd();
    116        it.Advance()) {
    117     const DictionaryValue* file_entry = NULL;
    118     if (!it.value().GetAsDictionary(&file_entry))
    119       continue;
    120     const base::Value* path_value;
    121     if (!file_entry->Get(kFileEntryPath, &path_value))
    122       continue;
    123     base::FilePath file_path;
    124     if (!GetValueAsFilePath(*path_value, &file_path))
    125       continue;
    126     bool is_directory = false;
    127     file_entry->GetBoolean(kFileEntryIsDirectory, &is_directory);
    128     int sequence_number = 0;
    129     if (!file_entry->GetInteger(kFileEntrySequenceNumber, &sequence_number))
    130       continue;
    131     if (!sequence_number)
    132       continue;
    133     result.push_back(
    134         SavedFileEntry(it.key(), file_path, is_directory, sequence_number));
    135   }
    136   return result;
    137 }
    138 
    139 }  // namespace
    140 
    141 SavedFileEntry::SavedFileEntry() : is_directory(false), sequence_number(0) {}
    142 
    143 SavedFileEntry::SavedFileEntry(const std::string& id,
    144                                const base::FilePath& path,
    145                                bool is_directory,
    146                                int sequence_number)
    147     : id(id),
    148       path(path),
    149       is_directory(is_directory),
    150       sequence_number(sequence_number) {}
    151 
    152 class SavedFilesService::SavedFiles {
    153  public:
    154   SavedFiles(Profile* profile, const std::string& extension_id);
    155   ~SavedFiles();
    156 
    157   void RegisterFileEntry(const std::string& id,
    158                          const base::FilePath& file_path,
    159                          bool is_directory);
    160   void EnqueueFileEntry(const std::string& id);
    161   bool IsRegistered(const std::string& id) const;
    162   const SavedFileEntry* GetFileEntry(const std::string& id) const;
    163   std::vector<SavedFileEntry> GetAllFileEntries() const;
    164 
    165  private:
    166   // Compacts sequence numbers if the largest sequence number is
    167   // g_max_sequence_number. Outside of testing, it is set to kint32max, so this
    168   // will almost never do any real work.
    169   void MaybeCompactSequenceNumbers();
    170 
    171   void LoadSavedFileEntriesFromPreferences();
    172 
    173   Profile* profile_;
    174   const std::string extension_id_;
    175 
    176   // Contains all file entries that have been registered, keyed by ID. Owns
    177   // values.
    178   base::hash_map<std::string, SavedFileEntry*> registered_file_entries_;
    179   STLValueDeleter<base::hash_map<std::string, SavedFileEntry*> >
    180       registered_file_entries_deleter_;
    181 
    182   // The queue of file entries that have been retained, keyed by
    183   // sequence_number. Values are a subset of values in registered_file_entries_.
    184   // This should be kept in sync with file entries stored in extension prefs.
    185   std::map<int, SavedFileEntry*> saved_file_lru_;
    186 
    187   DISALLOW_COPY_AND_ASSIGN(SavedFiles);
    188 };
    189 
    190 // static
    191 SavedFilesService* SavedFilesService::Get(Profile* profile) {
    192   return SavedFilesServiceFactory::GetForProfile(profile);
    193 }
    194 
    195 SavedFilesService::SavedFilesService(Profile* profile)
    196     : extension_id_to_saved_files_deleter_(&extension_id_to_saved_files_),
    197       profile_(profile) {
    198   registrar_.Add(this,
    199                  chrome::NOTIFICATION_EXTENSION_HOST_DESTROYED,
    200                  content::NotificationService::AllSources());
    201   registrar_.Add(this,
    202                  chrome::NOTIFICATION_APP_TERMINATING,
    203                  content::NotificationService::AllSources());
    204 }
    205 
    206 SavedFilesService::~SavedFilesService() {}
    207 
    208 void SavedFilesService::Observe(int type,
    209                                 const content::NotificationSource& source,
    210                                 const content::NotificationDetails& details) {
    211   switch (type) {
    212     case chrome::NOTIFICATION_EXTENSION_HOST_DESTROYED: {
    213       ExtensionHost* host = content::Details<ExtensionHost>(details).ptr();
    214       const Extension* extension = host->extension();
    215       if (extension) {
    216         ClearQueueIfNoRetainPermission(extension);
    217         Clear(extension->id());
    218       }
    219       break;
    220     }
    221 
    222     case chrome::NOTIFICATION_APP_TERMINATING: {
    223       // Stop listening to NOTIFICATION_EXTENSION_HOST_DESTROYED in particular
    224       // as all extension hosts will be destroyed as a result of shutdown.
    225       registrar_.RemoveAll();
    226       break;
    227     }
    228   }
    229 }
    230 
    231 void SavedFilesService::RegisterFileEntry(const std::string& extension_id,
    232                                           const std::string& id,
    233                                           const base::FilePath& file_path,
    234                                           bool is_directory) {
    235   GetOrInsert(extension_id)->RegisterFileEntry(id, file_path, is_directory);
    236 }
    237 
    238 void SavedFilesService::EnqueueFileEntry(const std::string& extension_id,
    239                                          const std::string& id) {
    240   GetOrInsert(extension_id)->EnqueueFileEntry(id);
    241 }
    242 
    243 std::vector<SavedFileEntry> SavedFilesService::GetAllFileEntries(
    244     const std::string& extension_id) {
    245   SavedFiles* saved_files = Get(extension_id);
    246   if (saved_files)
    247     return saved_files->GetAllFileEntries();
    248   return GetSavedFileEntries(ExtensionPrefs::Get(profile_), extension_id);
    249 }
    250 
    251 bool SavedFilesService::IsRegistered(const std::string& extension_id,
    252                                      const std::string& id) {
    253   return GetOrInsert(extension_id)->IsRegistered(id);
    254 }
    255 
    256 const SavedFileEntry* SavedFilesService::GetFileEntry(
    257     const std::string& extension_id,
    258     const std::string& id) {
    259   return GetOrInsert(extension_id)->GetFileEntry(id);
    260 }
    261 
    262 void SavedFilesService::ClearQueueIfNoRetainPermission(
    263     const Extension* extension) {
    264   if (!extension->GetActivePermissions()->HasAPIPermission(
    265           APIPermission::kFileSystemRetainEntries)) {
    266     ClearQueue(extension);
    267   }
    268 }
    269 
    270 void SavedFilesService::ClearQueue(const extensions::Extension* extension) {
    271   ClearSavedFileEntries(ExtensionPrefs::Get(profile_), extension->id());
    272   Clear(extension->id());
    273 }
    274 
    275 SavedFilesService::SavedFiles* SavedFilesService::Get(
    276     const std::string& extension_id) const {
    277   std::map<std::string, SavedFiles*>::const_iterator it =
    278       extension_id_to_saved_files_.find(extension_id);
    279   if (it != extension_id_to_saved_files_.end())
    280     return it->second;
    281 
    282   return NULL;
    283 }
    284 
    285 SavedFilesService::SavedFiles* SavedFilesService::GetOrInsert(
    286     const std::string& extension_id) {
    287   SavedFiles* saved_files = Get(extension_id);
    288   if (saved_files)
    289     return saved_files;
    290 
    291   saved_files = new SavedFiles(profile_, extension_id);
    292   extension_id_to_saved_files_.insert(
    293       std::make_pair(extension_id, saved_files));
    294   return saved_files;
    295 }
    296 
    297 void SavedFilesService::Clear(const std::string& extension_id) {
    298   std::map<std::string, SavedFiles*>::iterator it =
    299       extension_id_to_saved_files_.find(extension_id);
    300   if (it != extension_id_to_saved_files_.end()) {
    301     delete it->second;
    302     extension_id_to_saved_files_.erase(it);
    303   }
    304 }
    305 
    306 SavedFilesService::SavedFiles::SavedFiles(Profile* profile,
    307                                           const std::string& extension_id)
    308     : profile_(profile),
    309       extension_id_(extension_id),
    310       registered_file_entries_deleter_(&registered_file_entries_) {
    311   LoadSavedFileEntriesFromPreferences();
    312 }
    313 
    314 SavedFilesService::SavedFiles::~SavedFiles() {}
    315 
    316 void SavedFilesService::SavedFiles::RegisterFileEntry(
    317     const std::string& id,
    318     const base::FilePath& file_path,
    319     bool is_directory) {
    320   if (ContainsKey(registered_file_entries_, id))
    321     return;
    322 
    323   registered_file_entries_.insert(
    324       std::make_pair(id, new SavedFileEntry(id, file_path, is_directory, 0)));
    325 }
    326 
    327 void SavedFilesService::SavedFiles::EnqueueFileEntry(const std::string& id) {
    328   base::hash_map<std::string, SavedFileEntry*>::iterator it =
    329       registered_file_entries_.find(id);
    330   DCHECK(it != registered_file_entries_.end());
    331 
    332   SavedFileEntry* file_entry = it->second;
    333   int old_sequence_number = file_entry->sequence_number;
    334   if (!saved_file_lru_.empty()) {
    335     // Get the sequence number after the last file entry in the LRU.
    336     std::map<int, SavedFileEntry*>::reverse_iterator it =
    337         saved_file_lru_.rbegin();
    338     if (it->second == file_entry)
    339       return;
    340 
    341     file_entry->sequence_number = it->first + 1;
    342   } else {
    343     // The first sequence number is 1, as 0 means the entry is not in the LRU.
    344     file_entry->sequence_number = 1;
    345   }
    346   saved_file_lru_.insert(
    347       std::make_pair(file_entry->sequence_number, file_entry));
    348   ExtensionPrefs* prefs = ExtensionPrefs::Get(profile_);
    349   if (old_sequence_number) {
    350     saved_file_lru_.erase(old_sequence_number);
    351     UpdateSavedFileEntry(prefs, extension_id_, *file_entry);
    352   } else {
    353     AddSavedFileEntry(prefs, extension_id_, *file_entry);
    354     if (saved_file_lru_.size() > g_max_saved_file_entries) {
    355       std::map<int, SavedFileEntry*>::iterator it = saved_file_lru_.begin();
    356       it->second->sequence_number = 0;
    357       RemoveSavedFileEntry(prefs, extension_id_, it->second->id);
    358       saved_file_lru_.erase(it);
    359     }
    360   }
    361   MaybeCompactSequenceNumbers();
    362 }
    363 
    364 bool SavedFilesService::SavedFiles::IsRegistered(const std::string& id) const {
    365   return ContainsKey(registered_file_entries_, id);
    366 }
    367 
    368 const SavedFileEntry* SavedFilesService::SavedFiles::GetFileEntry(
    369     const std::string& id) const {
    370   base::hash_map<std::string, SavedFileEntry*>::const_iterator it =
    371       registered_file_entries_.find(id);
    372   if (it == registered_file_entries_.end())
    373     return NULL;
    374 
    375   return it->second;
    376 }
    377 
    378 std::vector<SavedFileEntry> SavedFilesService::SavedFiles::GetAllFileEntries()
    379     const {
    380   std::vector<SavedFileEntry> result;
    381   for (base::hash_map<std::string, SavedFileEntry*>::const_iterator it =
    382            registered_file_entries_.begin();
    383        it != registered_file_entries_.end();
    384        ++it) {
    385     result.push_back(*it->second);
    386   }
    387   return result;
    388 }
    389 
    390 void SavedFilesService::SavedFiles::MaybeCompactSequenceNumbers() {
    391   DCHECK_GE(g_max_sequence_number, 0);
    392   DCHECK_GE(static_cast<size_t>(g_max_sequence_number),
    393             g_max_saved_file_entries);
    394   std::map<int, SavedFileEntry*>::reverse_iterator it =
    395       saved_file_lru_.rbegin();
    396   if (it == saved_file_lru_.rend())
    397     return;
    398 
    399   // Only compact sequence numbers if the last entry's sequence number is the
    400   // maximum value.  This should almost never be the case.
    401   if (it->first < g_max_sequence_number)
    402     return;
    403 
    404   int sequence_number = 0;
    405   ExtensionPrefs* prefs = ExtensionPrefs::Get(profile_);
    406   for (std::map<int, SavedFileEntry*>::iterator it = saved_file_lru_.begin();
    407        it != saved_file_lru_.end();
    408        ++it) {
    409     sequence_number++;
    410     if (it->second->sequence_number == sequence_number)
    411       continue;
    412 
    413     SavedFileEntry* file_entry = it->second;
    414     file_entry->sequence_number = sequence_number;
    415     UpdateSavedFileEntry(prefs, extension_id_, *file_entry);
    416     saved_file_lru_.erase(it++);
    417     // Provide the following element as an insert hint. While optimized
    418     // insertion time with the following element as a hint is only supported by
    419     // the spec in C++11, the implementations do support this.
    420     it = saved_file_lru_.insert(
    421         it, std::make_pair(file_entry->sequence_number, file_entry));
    422   }
    423 }
    424 
    425 void SavedFilesService::SavedFiles::LoadSavedFileEntriesFromPreferences() {
    426   ExtensionPrefs* prefs = ExtensionPrefs::Get(profile_);
    427   std::vector<SavedFileEntry> saved_entries =
    428       GetSavedFileEntries(prefs, extension_id_);
    429   for (std::vector<SavedFileEntry>::iterator it = saved_entries.begin();
    430        it != saved_entries.end();
    431        ++it) {
    432     SavedFileEntry* file_entry = new SavedFileEntry(*it);
    433     registered_file_entries_.insert(std::make_pair(file_entry->id, file_entry));
    434     saved_file_lru_.insert(
    435         std::make_pair(file_entry->sequence_number, file_entry));
    436   }
    437 }
    438 
    439 // static
    440 void SavedFilesService::SetMaxSequenceNumberForTest(int max_value) {
    441   g_max_sequence_number = max_value;
    442 }
    443 
    444 // static
    445 void SavedFilesService::ClearMaxSequenceNumberForTest() {
    446   g_max_sequence_number = kMaxSequenceNumber;
    447 }
    448 
    449 // static
    450 void SavedFilesService::SetLruSizeForTest(int size) {
    451   g_max_saved_file_entries = size;
    452 }
    453 
    454 // static
    455 void SavedFilesService::ClearLruSizeForTest() {
    456   g_max_saved_file_entries = kMaxSavedFileEntries;
    457 }
    458 
    459 }  // namespace apps
    460