Speed up IDB by trimming down the BlobChangeMaps. Check to see if we need each

content/browser/indexed_db/indexed_db_backing_store.cc

 // Copyright (c) 2013 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 "content/browser/indexed_db/indexed_db_backing_store.h"
 
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/format_macros.h"
 #include "base/json/json_reader.h"
@@ skipping 1866 matching lines @@
     return s;
   DCHECK_GE(version, 0);
   const std::string object_store_data_key =
       ObjectStoreDataKey::Encode(database_id, object_store_id, key);
 
   std::string v;
   EncodeVarInt(version, &v);
   v.append(value.bits);
 
   leveldb_transaction->Put(object_store_data_key, &v);
-  transaction->PutBlobInfo(database_id,
-                           object_store_id,
-                           object_store_data_key,
-                           &value.blob_info,
-                           handles);
+  s = transaction->PutBlobInfoIfNeeded(database_id,
+                                       object_store_id,
+                                       object_store_data_key,
+                                       &value.blob_info,
+                                       handles);
+  if (!s.ok())
+    return s;
   DCHECK(!handles->size());
 
   const std::string exists_entry_key =
       ExistsEntryKey::Encode(database_id, object_store_id, key);
   std::string version_encoded;
   EncodeInt(version, &version_encoded);
   leveldb_transaction->Put(exists_entry_key, &version_encoded);
 
   std::string key_encoded;
   EncodeIDBKey(key, &key_encoded);
@@ skipping 28 matching lines @@
     int64 object_store_id,
     const RecordIdentifier& record_identifier) {
   IDB_TRACE("IndexedDBBackingStore::DeleteRecord");
   if (!KeyPrefix::ValidIds(database_id, object_store_id))
     return InvalidDBKeyStatus();
   LevelDBTransaction* leveldb_transaction = transaction->transaction();
 
   const std::string object_store_data_key = ObjectStoreDataKey::Encode(
       database_id, object_store_id, record_identifier.primary_key());
   leveldb_transaction->Remove(object_store_data_key);
-  transaction->PutBlobInfo(
+  leveldb::Status s = transaction->PutBlobInfoIfNeeded(
       database_id, object_store_id, object_store_data_key, NULL, NULL);
+  if (!s.ok())
+    return s;
 
   const std::string exists_entry_key = ExistsEntryKey::Encode(
       database_id, object_store_id, record_identifier.primary_key());
   leveldb_transaction->Remove(exists_entry_key);
   return leveldb::Status::OK();
 }
 
 leveldb::Status IndexedDBBackingStore::DeleteRange(
     IndexedDBBackingStore::Transaction* transaction,
     int64 database_id,
@@ skipping 2186 matching lines @@
   scoped_ptr<IndexedDBBackingStore::BlobChangeRecord> record(
       new BlobChangeRecord(key_, object_store_id_));
   record->blob_info_ = blob_info_;
 
   ScopedVector<webkit_blob::BlobDataHandle>::const_iterator iter;
   for (iter = handles_.begin(); iter != handles_.end(); ++iter)
     record->handles_.push_back(new webkit_blob::BlobDataHandle(**iter));
   return record.Pass();
 }
 
+leveldb::Status IndexedDBBackingStore::Transaction::PutBlobInfoIfNeeded(
+    int64 database_id,
+    int64 object_store_id,
+    const std::string& object_store_data_key,
+    std::vector<IndexedDBBlobInfo>* blob_info,
+    ScopedVector<webkit_blob::BlobDataHandle>* handles) {
+  if (!blob_info || blob_info->empty()) {
+    blob_change_map_.erase(object_store_data_key);
+    incognito_blob_map_.erase(object_store_data_key);
+
+    BlobEntryKey blob_entry_key;
+    StringPiece leveldb_key_piece(object_store_data_key);
+    if (!BlobEntryKey::FromObjectStoreDataKey(&leveldb_key_piece,
+                                              &blob_entry_key)) {
+      NOTREACHED();
+      return InternalInconsistencyStatus();
+    }
+    std::string value;
+    bool found = false;
+    leveldb::Status s =
+        transaction()->Get(blob_entry_key.Encode(), &value, &found);
+    if (!s.ok())
+      return s;
+    if (!found)
+      return leveldb::Status::OK();
+  }
+  PutBlobInfo(
+      database_id, object_store_id, object_store_data_key, blob_info, handles);
+  return leveldb::Status::OK();
+}
+
 // This is storing an info, even if empty, even if the previous key had no blob
 // info that we know of.  It duplicates a bunch of information stored in the
 // leveldb transaction, but only w.r.t. the user keys altered--we don't keep the
 // changes to exists or index keys here.
 void IndexedDBBackingStore::Transaction::PutBlobInfo(
     int64 database_id,
     int64 object_store_id,
     const std::string& object_store_data_key,
     std::vector<IndexedDBBlobInfo>* blob_info,
     ScopedVector<webkit_blob::BlobDataHandle>* handles) {
@@ skipping 20 matching lines @@
     const GURL& url,
     int64_t key)
     : is_file_(false), url_(url), key_(key) {}
 
 IndexedDBBackingStore::Transaction::WriteDescriptor::WriteDescriptor(
     const FilePath& file_path,
     int64_t key)
     : is_file_(true), file_path_(file_path), key_(key) {}
 
 }  // namespace content