Database support for GDataDirectoryService.

chrome/browser/chromeos/gdata/gdata_file_system.cc

Index: chrome/browser/chromeos/gdata/gdata_file_system.cc
===================================================================
--- chrome/browser/chromeos/gdata/gdata_file_system.cc	(revision 149888)
+++ chrome/browser/chromeos/gdata/gdata_file_system.cc	(working copy)
@@ -8,6 +8,7 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/json/json_reader.h"
@@ -27,6 +28,7 @@
 #include "chrome/browser/chromeos/gdata/gdata_util.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
@@ -45,6 +47,8 @@
     FILE_PATH_LITERAL("account_metadata.json");
 const FilePath::CharType kFilesystemProtoFile[] =
     FILE_PATH_LITERAL("file_system.pb");
+const FilePath::CharType kResourceMetadataDBFile[] =
+    FILE_PATH_LITERAL("resource_metadata.db");
 
 const char kEmptyFilePath[] = "/dev/null";
 
@@ -75,28 +79,6 @@
 #endif
 };
 
-// Defines set of parameters sent to callback OnProtoLoaded().
-struct LoadRootFeedParams {
-  LoadRootFeedParams(
-        FilePath search_file_path,
-        bool should_load_from_server,
-        const FindEntryCallback& callback)
-        : search_file_path(search_file_path),
-          should_load_from_server(should_load_from_server),
-          load_error(GDATA_FILE_OK),
-          callback(callback) {
-    }
-  ~LoadRootFeedParams() {
-  }
-
-  FilePath search_file_path;
-  bool should_load_from_server;
-  std::string proto;
-  GDataFileError load_error;
-  base::Time last_modified;
-  const FindEntryCallback callback;
-};
-
 // Returns true if file system is due to be serialized on disk based on it
 // |serialized_size| and |last_serialized| timestamp.
 bool ShouldSerializeFileSystemNow(size_t serialized_size,
@@ -270,6 +252,11 @@
   }
 }
 
+bool UseLevelDB() {
+  return CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kUseLevelDBForGData);
+}
+
 // Gets the file size of |local_file|.
 void GetLocalFileSizeOnBlockingPool(const FilePath& local_file,
                                     GDataFileError* error,
@@ -950,6 +937,9 @@
     const FindEntryCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  DVLOG(1) << "ReloadFeedFromServerIfNeeded local_changestamp="
+           << local_changestamp << ", initial_origin=" << initial_origin;
+
   // First fetch the latest changestamp to see if there were any new changes
   // there at all.
   documents_service_->GetAccountMetadata(
@@ -1112,7 +1102,7 @@
   }
 
   // Save file system metadata to disk.
-  SaveFileSystemAsProto();
+  SaveFileSystem();
 
   // If we had someone to report this too, then this retrieval was done in a
   // context of search... so continue search.
@@ -2878,17 +2868,25 @@
     const FindEntryCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  const FilePath path =
-      cache_->GetCacheDirectoryPath(GDataCache::CACHE_TYPE_META).Append(
-          kFilesystemProtoFile);
   LoadRootFeedParams* params = new LoadRootFeedParams(search_file_path,
                                                       should_load_from_server,
                                                       callback);
-  BrowserThread::GetBlockingPool()->PostTaskAndReply(FROM_HERE,
-      base::Bind(&LoadProtoOnBlockingPool, path, params),
-      base::Bind(&GDataWapiFeedLoader::OnProtoLoaded,
-                 weak_ptr_factory_.GetWeakPtr(),
-                 base::Owned(params)));
+  FilePath path = cache_->GetCacheDirectoryPath(GDataCache::CACHE_TYPE_META);
+  if (UseLevelDB()) {
+    path = path.Append(kResourceMetadataDBFile);
+    directory_service_->InitFromDB(path, blocking_task_runner_,
+        &params->load_error, base::Bind(

[satorux1, 2012/08/03 22:17:26]

I think I was confused about this |load_error| parameter.

Can you check params->load_error before calling InitFromDB? If this is not OK
here, we don't have to call InitFromDB, right?

Then, I think we can get rid of the error parameter from InitFromDB, because 

[achuithb, 2012/08/03 22:25:58]

because? The suspense is killing me ;)

We need to set the error in the case where the db is not found because we use
this as a signal to let the user know we are refreshing drive for the first
time.

error is definitely OK over here since we just created the param. I'll replace
the runtime check with a DCHECK instead.

[satorux1, 2012/08/03 22:33:30]

oops, here's what I was thinking:

Instead of passing GDataFileError* to InitFromDB(), I think the callback should
get the error as a parameter, then modify params->load_error as needed in the
callbck function

[achuithb, 2012/08/03 23:27:35]

Done.

+            &GDataWapiFeedLoader::ContinueWithInitializedDirectoryService,
+            weak_ptr_factory_.GetWeakPtr(),
+            base::Owned(params)));
+  } else {
+    path = path.Append(kFilesystemProtoFile);
+    BrowserThread::GetBlockingPool()->PostTaskAndReply(FROM_HERE,
+        base::Bind(&LoadProtoOnBlockingPool, path, params),
+        base::Bind(&GDataWapiFeedLoader::OnProtoLoaded,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   base::Owned(params)));
+  }
 }
 
 void GDataFileSystem::OnDirectoryChanged(const FilePath& directory_path) {
@@ -2940,7 +2938,6 @@
   if (directory_service_->origin() == FROM_SERVER)
     return;
 
-  int local_changestamp = 0;
   // Update directory structure only if everything is OK and we haven't yet
   // received the feed from the server yet.
   if (params->load_error == GDATA_FILE_OK) {
@@ -2948,13 +2945,23 @@
     if (directory_service_->ParseFromString(params->proto)) {
       directory_service_->set_last_serialized(params->last_modified);
       directory_service_->set_serialized_size(params->proto.size());
-      local_changestamp = directory_service_->largest_changestamp();
     } else {
       params->load_error = GDATA_FILE_ERROR_FAILED;
       LOG(WARNING) << "Parse of cached proto file failed";
     }
   }
 
+  ContinueWithInitializedDirectoryService(params);
+}
+
+void GDataWapiFeedLoader::ContinueWithInitializedDirectoryService(
+    LoadRootFeedParams* params) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  DVLOG(1) << "Time elapsed to load directory service from disk="
+           << (base::Time::Now() - params->load_start_time).InMilliseconds()
+           << " milliseconds";
+
   FindEntryCallback callback = params->callback;
   // If we got feed content from cache, try search over it.
   if (params->load_error == GDATA_FILE_OK && !callback.is_null()) {
@@ -2985,33 +2992,35 @@
   // |reported| to the original callback, then we just need to refresh the
   // content without continuing search upon operation completion.
   ReloadFromServerIfNeeded(initial_origin,
-                           local_changestamp,
+                           directory_service_->largest_changestamp(),
                            params->search_file_path,
                            callback);
 }
 
-void GDataWapiFeedLoader::SaveFileSystemAsProto() {
+void GDataWapiFeedLoader::SaveFileSystem() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  DVLOG(1) << "SaveFileSystemAsProto";
-
   if (!ShouldSerializeFileSystemNow(directory_service_->serialized_size(),
                                     directory_service_->last_serialized())) {
     return;
   }
 
-  const FilePath path =
-      cache_->GetCacheDirectoryPath(GDataCache::CACHE_TYPE_META).Append(
-          kFilesystemProtoFile);
-  scoped_ptr<std::string> serialized_proto(new std::string());
-  directory_service_->SerializeToString(serialized_proto.get());
-  directory_service_->set_last_serialized(base::Time::Now());
-  directory_service_->set_serialized_size(serialized_proto->size());
-  PostBlockingPoolSequencedTask(
-      FROM_HERE,
-      blocking_task_runner_,
-      base::Bind(&SaveProtoOnBlockingPool, path,
-                 base::Passed(serialized_proto.Pass())));
+  if (UseLevelDB()) {
+    directory_service_->SaveToDB();
+  } else {
+    const FilePath path =
+        cache_->GetCacheDirectoryPath(GDataCache::CACHE_TYPE_META).Append(
+            kFilesystemProtoFile);
+    scoped_ptr<std::string> serialized_proto(new std::string());
+    directory_service_->SerializeToString(serialized_proto.get());
+    directory_service_->set_last_serialized(base::Time::Now());
+    directory_service_->set_serialized_size(serialized_proto->size());
+    PostBlockingPoolSequencedTask(
+        FROM_HERE,
+        blocking_task_runner_,
+        base::Bind(&SaveProtoOnBlockingPool, path,
+                   base::Passed(serialized_proto.Pass())));
+  }
 }
 
 void GDataFileSystem::OnFilePathUpdated(const FileOperationCallback& callback,
@@ -3388,10 +3397,11 @@
     GDataEntry* entry) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  DVLOG(1) << "Initial load finished";
   if (!callback.is_null())
     callback.Run(error, entry);
 
+  DVLOG(1) << "RunAndNotifyInitialLoadFinished";
+
   // Notify the observers that root directory has been initialized.
   FOR_EACH_OBSERVER(GDataFileSystemInterface::Observer, observers_,
                     OnInitialLoadFinished());