[fsp] Store mounted file systems in preferences.

chrome/browser/chromeos/file_system_provider/service.cc

Index: chrome/browser/chromeos/file_system_provider/service.cc
diff --git a/chrome/browser/chromeos/file_system_provider/service.cc b/chrome/browser/chromeos/file_system_provider/service.cc
index c989766f166c9add902e3a2614e5dde7a879fce8..281a3d3fa69431741eabf95d7714d3f4d10112bc 100644
--- a/chrome/browser/chromeos/file_system_provider/service.cc
+++ b/chrome/browser/chromeos/file_system_provider/service.cc
@@ -5,6 +5,8 @@
 #include "chrome/browser/chromeos/file_system_provider/service.h"
 
 #include "base/files/file_path.h"
+#include "base/prefs/pref_service.h"
+#include "base/prefs/scoped_user_pref_update.h"
 #include "base/stl_util.h"
 #include "chrome/browser/chromeos/file_system_provider/mount_path_util.h"
 #include "chrome/browser/chromeos/file_system_provider/observer.h"
@@ -12,6 +14,8 @@
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_info.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_interface.h"
 #include "chrome/browser/chromeos/file_system_provider/service_factory.h"
+#include "chrome/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/extension_registry.h"
@@ -38,6 +42,12 @@ ProvidedFileSystemInterface* CreateProvidedFileSystem(
 
 }  // namespace
 
+void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterDictionaryPref(
+      prefs::kFSPMountedFileSystems,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+}
+
 Service::Service(Profile* profile,
                  extensions::ExtensionRegistry* extension_registry)
     : profile_(profile),
@@ -49,6 +59,7 @@ Service::Service(Profile* profile,
 
 Service::~Service() {
   extension_registry_->RemoveObserver(this);
+  RememberFileSystems();
 
   ProvidedFileSystemMap::iterator it = file_system_map_.begin();
   while (it != file_system_map_.end()) {
@@ -251,6 +262,11 @@ void Service::OnExtensionUnloaded(
     content::BrowserContext* browser_context,
     const extensions::Extension* extension,
     extensions::UnloadedExtensionInfo::Reason reason) {
+  // If the reason is not a profile shutdown, then forget the mounted file
+  // systems from preferences.
+  if (reason != extensions::UnloadedExtensionInfo::REASON_PROFILE_SHUTDOWN)
+    ForgetFileSystems(extension->id());
+
   // Unmount all of the provided file systems associated with this extension.
   ProvidedFileSystemMap::iterator it = file_system_map_.begin();
   while (it != file_system_map_.end()) {
@@ -267,6 +283,11 @@ void Service::OnExtensionUnloaded(
   }
 }
 
+void Service::OnExtensionLoaded(content::BrowserContext* browser_context,
+                                const extensions::Extension* extension) {
+  RestoreFileSystems(extension->id());
+}
+
 ProvidedFileSystemInterface* Service::GetProvidedFileSystem(
     const std::string& mount_point_name) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
@@ -297,5 +318,82 @@ void Service::OnRequestUnmountStatus(
   }
 }
 
+void Service::RememberFileSystems() {
+  base::DictionaryValue extensions;
+  const std::vector<ProvidedFileSystemInfo> file_system_info_list =
+      GetProvidedFileSystemInfoList();
+
+  for (std::vector<ProvidedFileSystemInfo>::const_iterator it =
+           file_system_info_list.begin();
+       it != file_system_info_list.end();
+       ++it) {
+    base::ListValue* file_systems = NULL;
+    if (!extensions.GetList(it->extension_id(), &file_systems)) {
+      file_systems = new base::ListValue();
+      extensions.Set(it->extension_id(), file_systems);
+    }
+
+    base::DictionaryValue* file_system = new base::DictionaryValue();
+    file_system->SetString("file_system_id", it->file_system_id());
+    file_system->SetString("file_system_name", it->file_system_name());

[hashimoto, 2014/05/26 08:35:38]

These keys should be constants.

[mtomasz, 2014/05/27 02:10:27]

Done.

+    file_systems->Append(file_system);
+  }
+
+  PrefService* pref_service = profile_->GetPrefs();
+  DCHECK(pref_service);
+  pref_service->Set(prefs::kFSPMountedFileSystems, extensions);

[hashimoto, 2014/05/26 08:35:38]

This overwrites the previously saved data.
Doesn't this result in erasing the mounted file systems when the device is
restarted twice, without loading the extension?

[mtomasz, 2014/05/27 02:10:27]

Yes, this basically remembers all *currently mounted* file systems, overriding
previous values. We don't want to remember file systems which failed to remount.

Shutdown can't happen before loading is finished, so there should be no
situation that RememberFileSystems() is called, before all installed extensions
are loaded.

[mtomasz, 2014/05/27 02:13:43]

This is because loading is synchronous. All installed extensions are loaded
synchronously in a loop. Hence, shutdown can't happen before all of them are
loaded.

+  pref_service->CommitPendingWrite();
+}
+
+void Service::ForgetFileSystems(const std::string& extension_id) {
+  PrefService* pref_service = profile_->GetPrefs();
+  DCHECK(pref_service);
+
+  DictionaryPrefUpdate update(pref_service, prefs::kFSPMountedFileSystems);
+  base::DictionaryValue* extensions = update.Get();
+  DCHECK(extensions);
+
+  extensions->Remove(extension_id, NULL);
+}
+
+void Service::RestoreFileSystems(const std::string& extension_id) {
+  PrefService* pref_service = profile_->GetPrefs();
+  DCHECK(pref_service);
+
+  const base::DictionaryValue* extensions =
+      pref_service->GetDictionary(prefs::kFSPMountedFileSystems);
+  DCHECK(extensions);
+
+  const base::ListValue* file_systems;

[hashimoto, 2014/05/26 08:35:38]

nit: Initialize this with NULL.

[mtomasz, 2014/05/27 02:10:27]

Done.

+
+  if (!extensions->GetList(extension_id, &file_systems))

[hashimoto, 2014/05/26 08:35:38]

Why other GetXXX calls are only DCHECKing the results while this line and L.385
abort on errors?

[mtomasz, 2014/05/27 01:13:14]

Extension doesn't need to be in preferences, eg. if it just got installed. In
such situation, we shouldn't crash, since it is not an error.

However, #374, #379 catch malformed preferences, so we should crash.

[hashimoto, 2014/05/27 11:29:24]

Then maybe we should emit LOG for empty file_system_id and file_system_name too?

[mtomasz, 2014/05/28 02:02:19]

Done.

+    return;
+
+  for (size_t i = 0; i < file_systems->GetSize(); ++i) {
+    const base::DictionaryValue* file_system = NULL;
+    file_systems->GetDictionary(i, &file_system);
+    DCHECK(file_system);
+
+    std::string file_system_id;
+    file_system->GetString("file_system_id", &file_system_id);
+    DCHECK(!file_system_id.empty());
+
+    std::string file_system_name;
+    file_system->GetString("file_system_name", &file_system_name);
+    DCHECK(!file_system_name.empty());
+
+    if (file_system_id.empty() || file_system_name.empty())
+      continue;
+
+    const bool result =
+        MountFileSystem(extension_id, file_system_id, file_system_name);
+    if (!result) {
+      LOG(ERROR) << "Failed to restore a provided file system from "
+                 << "preferences: " << extension_id << ", " << file_system_id
+                 << ", " << file_system_name << ".";
+    }
+  }
+}
+
 }  // namespace file_system_provider
 }  // namespace chromeos