[SyncFS] Build indexes from FileTracker entries on disk.

It is assumed that no indexes exist before.

BUG=347425
TEST=./unit_tests --gtest_filter="MetadataDatabaseIndexOnDiskTest.*"

Review URL: https://codereview.chromium.org/391623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283759 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync_file_system/drive_backend/metadata_database_index_on_disk.cc

@@ -556,6 +556,27 @@ MetadataDatabaseIndexOnDisk::GetAllMetadataIDs() const {
   return file_ids;
 }
 
+void MetadataDatabaseIndexOnDisk::BuildTrackerIndexes(
+    leveldb::WriteBatch* batch) {
+  scoped_ptr<leveldb::Iterator> itr(db_->NewIterator(leveldb::ReadOptions()));
+  for (itr->Seek(kFileTrackerKeyPrefix); itr->Valid(); itr->Next()) {
+    if (!RemovePrefix(itr->key().ToString(), kFileTrackerKeyPrefix, NULL))
+      break;
+
+    FileTracker tracker;
+    if (!tracker.ParseFromString(itr->value().ToString())) {
+      util::Log(logging::LOG_WARNING, FROM_HERE,
+                "Failed to parse a Tracker");
+      continue;
+    }
+
+    AddToAppIDIndex(tracker, batch);
+    AddToFileIDIndexes(tracker, batch);
+    AddToPathIndexes(tracker, batch);
+    AddToDirtyTrackerIndexes(tracker, batch);
+  }
+}
+
 MetadataDatabaseIndexOnDisk::MetadataDatabaseIndexOnDisk(leveldb::DB* db)
     : db_(db) {
   // TODO(peria): Add UMA to measure the number of FileMetadata, FileTracker,

chrome/browser/sync_file_system/drive_backend/metadata_database_index_on_disk.h

@@ -79,6 +79,9 @@ class MetadataDatabaseIndexOnDisk : public MetadataDatabaseIndexInterface {
   virtual std::vector<int64> GetAllTrackerIDs() const OVERRIDE;
   virtual std::vector<std::string> GetAllMetadataIDs() const OVERRIDE;
 
+  // Builds on-disk indexes from FileTracker entries on disk.
+  void BuildTrackerIndexes(leveldb::WriteBatch* batch);
+
  private:
   enum NumEntries {
     NONE,      // No entries are found.

chrome/browser/sync_file_system/drive_backend/metadata_database_index_on_disk_unittest.cc

@@ -183,6 +183,35 @@ TEST_F(MetadataDatabaseIndexOnDiskTest, SetEntryTest) {
   EXPECT_FALSE(index()->GetFileTracker(tracker_id, NULL));
 }
 
+TEST_F(MetadataDatabaseIndexOnDiskTest, BuildIndexTest) {
+  CreateTestDatabase(false);
+
+  TrackerIDSet tracker_ids;
+  // Before building indexes, no references exist.
+  EXPECT_EQ(kInvalidTrackerID, index()->GetAppRootTracker("app_id"));
+  tracker_ids = index()->GetFileTrackerIDsByFileID("file_id");
+  EXPECT_TRUE(tracker_ids.empty());
+  tracker_ids = index()->GetFileTrackerIDsByParentAndTitle(
+      kAppRootTrackerID, "file");
+  EXPECT_TRUE(tracker_ids.empty());
+  EXPECT_EQ(0U, index()->CountDirtyTracker());
+
+  scoped_ptr<leveldb::WriteBatch> batch(new leveldb::WriteBatch);
+  index()->BuildTrackerIndexes(batch.get());
+  WriteToDB(batch.Pass());
+
+  // After building indexes, we should have correct indexes.
+  EXPECT_EQ(kAppRootTrackerID, index()->GetAppRootTracker("app_id"));
+  tracker_ids = index()->GetFileTrackerIDsByFileID("file_id");
+  EXPECT_EQ(1U, tracker_ids.size());
+  EXPECT_EQ(kFileTrackerID, tracker_ids.active_tracker());
+  tracker_ids = index()->GetFileTrackerIDsByParentAndTitle(
+      kAppRootTrackerID, "file");
+  EXPECT_EQ(1U, tracker_ids.size());
+  EXPECT_EQ(kFileTrackerID, tracker_ids.active_tracker());
+  EXPECT_EQ(1U, index()->CountDirtyTracker());
+}
+
 TEST_F(MetadataDatabaseIndexOnDiskTest, AllEntriesTest) {
   CreateTestDatabase(true);
 
@@ -352,7 +381,7 @@ TEST_F(MetadataDatabaseIndexOnDiskTest, TrackerIDSetByParentIDAndTitleTest) {
 
   tracker_ids = index()->GetFileTrackerIDsByParentAndTitle(
       kAppRootTrackerID, "file2");
-  EXPECT_EQ(0U, tracker_ids.size());
+  EXPECT_TRUE(tracker_ids.empty());
 
   const int64 tracker_id = 72;
   // Testing AddToFileIDIndexes