IndexedDB: Recycle cursor objects when calling continue().

content/renderer/indexed_db_dispatcher.h

Index: content/renderer/indexed_db_dispatcher.h
diff --git a/content/renderer/indexed_db_dispatcher.h b/content/renderer/indexed_db_dispatcher.h
index e30fa95df5003552bab12d521b3746b69229568f..53a2f1801fc95e9443ec680f092fbb29e1899525 100644
--- a/content/renderer/indexed_db_dispatcher.h
+++ b/content/renderer/indexed_db_dispatcher.h
@@ -14,6 +14,7 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebIDBDatabase.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebIDBObjectStore.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebIDBTransactionCallbacks.h"
+#include <map>
 
 class IndexedDBKey;
 
@@ -153,6 +154,11 @@ class IndexedDBDispatcher : public IPC::Channel::Listener {
 
   static int32 TransactionId(const WebKit::WebIDBTransaction& transaction);
 
+  IndexedDBKey getCursorKey(int32 cursor_id);
+  IndexedDBKey getCursorPrimaryKey(int32 cursor_id);
+  content::SerializedScriptValue getCursorValue(int32 cursor_id);
+  void CursorDestroyed(int32 cursor_id);
+
  private:
   // IDBCallback message handlers.
   void OnSuccessNull(int32 response_id);
@@ -163,6 +169,10 @@ class IndexedDBDispatcher : public IPC::Channel::Listener {
                            const IndexedDBKey& key,
                            const IndexedDBKey& primary_key,
                            const content::SerializedScriptValue& value);
+  void OnSuccessCursorContinue(int32 response_id,
+                               const IndexedDBKey& key,
+                               const IndexedDBKey& primary_key,
+                               const content::SerializedScriptValue& value);
   void OnSuccessStringList(int32 response_id,
                            const std::vector<string16>& value);
   void OnSuccessSerializedScriptValue(
@@ -182,6 +192,14 @@ class IndexedDBDispatcher : public IPC::Channel::Listener {
   IDMap<WebKit::WebIDBDatabaseCallbacks, IDMapOwnPointer>
       pending_database_callbacks_;
 
+  // Map from response id to cursor id.
+  std::map<int32,int32> pending_cursor_continues_;
+
+  // FIXME: Double check these are only used on WebKit thread.

[dgrogan, 2011/10/29 00:54:28]

You could use IDMap and AddWithID.  IDMap ensures it's not called on multiple
threads.  But you don't have any threading problems.  Incoming messages are
already on the right thread by the time they get to IndexedDBDispatcher.

[hans, 2011/10/31 16:11:52]

OK, thanks.

+  std::map<int32, IndexedDBKey> cursor_key_; // Map from cursor id to key.
+  std::map<int32, IndexedDBKey> cursor_primary_key_;
+  std::map<int32, content::SerializedScriptValue> cursor_value_;
+
   DISALLOW_COPY_AND_ASSIGN(IndexedDBDispatcher);
 };