Add the backchannel for Blobs to be received into Blink from the database backend.

Source/modules/indexeddb/IDBCursor.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 20 matching lines @@
 #include "bindings/v8/NewScriptState.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/inspector/ScriptCallStack.h"
 #include "modules/indexeddb/IDBAny.h"
 #include "modules/indexeddb/IDBDatabase.h"
 #include "modules/indexeddb/IDBObjectStore.h"
 #include "modules/indexeddb/IDBTracing.h"
 #include "modules/indexeddb/IDBTransaction.h"
 #include "modules/indexeddb/WebIDBCallbacksImpl.h"
+#include "public/platform/WebBlobInfo.h"
 #include "public/platform/WebIDBDatabase.h"
 #include "public/platform/WebIDBKeyRange.h"
 #include <limits>
 
 using blink::WebIDBCursor;
 using blink::WebIDBDatabase;
 
 namespace WebCore {
 
 PassRefPtr<IDBCursor> IDBCursor::create(PassOwnPtr<blink::WebIDBCursor> backend, WebIDBCursor::Direction direction, IDBRequest* request, IDBAny* source, IDBTransaction* transaction)
@@ skipping 38 matching lines @@
 {
     ASSERT(m_backend);
     ASSERT(m_request);
     ASSERT(m_source->type() == IDBAny::IDBObjectStoreType || m_source->type() == IDBAny::IDBIndexType);
     ASSERT(m_transaction);
     ScriptWrappable::init(this);
 }
 
 IDBCursor::~IDBCursor()
 {
+    handleBlobAcks();
 }
 
 PassRefPtr<IDBRequest> IDBCursor::update(ExecutionContext* executionContext, ScriptValue& value, ExceptionState& exceptionState)
 {
     IDB_TRACE("IDBCursor::update");
 
     if (!m_gotValue) {
         exceptionState.throwDOMException(InvalidStateError, IDBDatabase::noValueErrorMessage);
         return nullptr;
     }
@@ skipping 175 matching lines @@
 void IDBCursor::postSuccessHandlerCallback()
 {
     if (m_backend)
         m_backend->postSuccessHandlerCallback();
 }
 
 void IDBCursor::close()
 {
     // The notifier may be the last reference to this cursor.
     RefPtr<IDBCursor> protect(this);
+    handleBlobAcks();
     m_request.clear();
     m_backend.clear();
 }
 
 void IDBCursor::checkForReferenceCycle()
 {
     // If this cursor and its request have the only references
     // to each other, then explicitly break the cycle.
     if (!m_request || m_request->getResultCursor() != this)
         return;
 
     if (!hasOneRef() || !m_request->hasOneRef())
         return;
 
+    handleBlobAcks();
     m_request.clear();
 }
 
 ScriptValue IDBCursor::key(NewScriptState* scriptState)
 {
     m_keyDirty = false;
     return idbKeyToScriptValue(scriptState, m_key);
 }
 
 ScriptValue IDBCursor::primaryKey(NewScriptState* scriptState)
 {
     m_primaryKeyDirty = false;
     return idbKeyToScriptValue(scriptState, m_primaryKey);
 }
 
 ScriptValue IDBCursor::value(NewScriptState* scriptState)
 {
     ASSERT(isCursorWithValue());
 
     RefPtr<IDBObjectStore> objectStore = effectiveObjectStore();
     const IDBObjectStoreMetadata& metadata = objectStore->metadata();
     RefPtr<IDBAny> value;
     if (metadata.autoIncrement && !metadata.keyPath.isNull()) {
-        value = IDBAny::create(m_value, m_primaryKey, metadata.keyPath);
+        value = IDBAny::create(m_value, m_blobInfo.get(), m_primaryKey, metadata.keyPath);
 #ifndef NDEBUG
-        assertPrimaryKeyValidOrInjectable(scriptState, m_value, m_primaryKey, metadata.keyPath);
+        assertPrimaryKeyValidOrInjectable(scriptState, m_value, m_blobInfo.get(), m_primaryKey, metadata.keyPath);
 #endif
     } else {
-        value = IDBAny::create(m_value);
+        value = IDBAny::create(m_value, m_blobInfo.get());
     }
 
     m_valueDirty = false;
-    return idbAnyToScriptValue(scriptState, value);
+    ScriptValue scriptValue = idbAnyToScriptValue(scriptState, value);
+    handleBlobAcks();
+    return scriptValue;
 }
 
 ScriptValue IDBCursor::source(NewScriptState* scriptState) const
 {
     return idbAnyToScriptValue(scriptState, m_source);
 }
 
-void IDBCursor::setValueReady(PassRefPtr<IDBKey> key, PassRefPtr<IDBKey> primaryKey, PassRefPtr<SharedBuffer> value)
+void IDBCursor::setValueReady(PassRefPtr<IDBKey> key, PassRefPtr<IDBKey> primaryKey, PassRefPtr<SharedBuffer> value, PassOwnPtr<Vector<blink::WebBlobInfo> > blobInfo)
 {
     m_key = key;
     m_keyDirty = true;
 
     m_primaryKey = primaryKey;
     m_primaryKeyDirty = true;
 
     if (isCursorWithValue()) {
         m_value = value;
+        m_blobInfo = blobInfo;

[jsbell, 2014/04/17 19:00:33]

If `value` is never accessed, the blobs remain unacked. If the cursor is
iterated, this overwrites m_blobInfo. Doesn't that mean the previous batch of
blobs won't be acked even when the cursor is freed?

[ericu, 2014/04/17 19:30:14]

Right, thanks; I've added a handleBlobAcks() call before the assignment to fix
it.  This does feel a little fragile, though.  It seems like what I want is a
custom destruction action on some kind of a scoped object, and then I just have
to remember to destroy it after creating the ScriptValue too.  But that seems
rather heavyweight to write just for this.

[jsbell, 2014/04/17 20:19:28]

Yeah. See comment on another review about propagating the IndexedDBValue (bits +
blobs) concept around.

         m_valueDirty = true;
     }
 
     m_gotValue = true;
 }
 
 PassRefPtr<IDBObjectStore> IDBCursor::effectiveObjectStore() const
 {
     if (m_source->type() == IDBAny::IDBObjectStoreType)
         return m_source->idbObjectStore();
     RefPtr<IDBIndex> index = m_source->idbIndex();
     return index->objectStore();
 }
 
 bool IDBCursor::isDeleted() const
 {
     if (m_source->type() == IDBAny::IDBObjectStoreType)
         return m_source->idbObjectStore()->isDeleted();
     return m_source->idbIndex()->isDeleted();
 }
 
+void IDBCursor::handleBlobAcks()
+{
+    if (m_blobInfo.get() && m_blobInfo->size()) {
+        ASSERT(m_request);

[jsbell, 2014/04/17 19:00:33]

Can we add a complementary ASSERT (outside the if), that if m_request is NULL
there are no blobs to ack?

[ericu, 2014/04/17 19:30:14]

Done.

+        m_request->transaction()->db()->ackReceivedBlobs(m_blobInfo.get());

[jsbell, 2014/04/17 19:00:33]

Can use m_transaction

[ericu, 2014/04/17 19:30:14]

Done.

+        m_blobInfo.clear();
+    }
+}
+
 WebIDBCursor::Direction IDBCursor::stringToDirection(const String& directionString, ExceptionState& exceptionState)
 {
     if (directionString.isNull() || directionString == IDBCursor::directionNext())
         return WebIDBCursor::Next;
     if (directionString == IDBCursor::directionNextUnique())
         return WebIDBCursor::NextNoDuplicate;
     if (directionString == IDBCursor::directionPrev())
         return WebIDBCursor::Prev;
     if (directionString == IDBCursor::directionPrevUnique())
         return WebIDBCursor::PrevNoDuplicate;
@@ skipping 17 matching lines @@
     case WebIDBCursor::PrevNoDuplicate:
         return IDBCursor::directionPrevUnique();
 
     default:
         ASSERT_NOT_REACHED();
         return IDBCursor::directionNext();
     }
 }
 
 } // namespace WebCore