Chromium Blob hacking

content/child/webblobregistry_impl.cc

Index: content/child/webblobregistry_impl.cc
diff --git a/content/child/webblobregistry_impl.cc b/content/child/webblobregistry_impl.cc
index a51f4ec837b8bbbadf068fe8c0f3ee1c9b22fa8b..d33c6adf71d0060362d123490501588cc0d1cea2 100644
--- a/content/child/webblobregistry_impl.cc
+++ b/content/child/webblobregistry_impl.cc
@@ -5,6 +5,7 @@
 #include "content/child/webblobregistry_impl.h"
 
 #include "base/files/file_path.h"
+#include "base/guid.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory.h"
 #include "base/message_loop/message_loop.h"
@@ -38,42 +39,11 @@ WebBlobRegistryImpl::WebBlobRegistryImpl(ThreadSafeSender* sender)
 WebBlobRegistryImpl::~WebBlobRegistryImpl() {
 }
 
-void WebBlobRegistryImpl::SendDataForBlob(const WebURL& url,
-                                          const WebThreadSafeData& data) {
-
-  if (data.size() == 0)
-    return;
-  if (data.size() < kLargeThresholdBytes) {
-    webkit_blob::BlobData::Item item;
-    item.SetToBytes(data.data(), data.size());
-    sender_->Send(new BlobHostMsg_AppendBlobDataItem(url, item));
-  } else {
-    // We handle larger amounts of data via SharedMemory instead of
-    // writing it directly to the IPC channel.
-    size_t shared_memory_size = std::min(
-        data.size(), kMaxSharedMemoryBytes);
-    scoped_ptr<base::SharedMemory> shared_memory(
-        ChildThread::AllocateSharedMemory(shared_memory_size,
-                                          sender_.get()));
-    CHECK(shared_memory.get());
+void WebBlobRegistryImpl::registerBlobData(
+    const WebKit::WebString& uuid, const WebKit::WebBlobData& data) {
+  const std::string uuid_str(uuid.utf8());
 
-    size_t data_size = data.size();
-    const char* data_ptr = data.data();
-    while (data_size) {
-      size_t chunk_size = std::min(data_size, shared_memory_size);
-      memcpy(shared_memory->memory(), data_ptr, chunk_size);
-      sender_->Send(new BlobHostMsg_SyncAppendSharedMemory(
-          url, shared_memory->handle(), chunk_size));
-      data_size -= chunk_size;
-      data_ptr += chunk_size;
-    }
-  }
-}
-
-void WebBlobRegistryImpl::registerBlobURL(
-    const WebURL& url, WebBlobData& data) {
-  DCHECK(ChildThread::current());

[ericu, 2013/08/21 23:26:09]

Why remove this DCHECK?

[michaeln, 2013/08/27 23:24:06]

Because soon, blink will be invoking these methods on background threads too.

-  sender_->Send(new BlobHostMsg_StartBuilding(url));
+  sender_->Send(new BlobHostMsg_StartBuilding(uuid_str));
   size_t i = 0;
   WebBlobData::Item data_item;
   while (data.itemAt(i++, data_item)) {
@@ -81,7 +51,7 @@ void WebBlobRegistryImpl::registerBlobURL(
       case WebBlobData::Item::TypeData: {
         // WebBlobData does not allow partial data items.
         DCHECK(!data_item.offset && data_item.length == -1);
-        SendDataForBlob(url, data_item.data);
+        SendDataForBlob(uuid_str, data_item.data);
         break;
       }
       case WebBlobData::Item::TypeFile:
@@ -93,7 +63,7 @@ void WebBlobRegistryImpl::registerBlobURL(
               static_cast<uint64>(data_item.length),
               base::Time::FromDoubleT(data_item.expectedModificationTime));
           sender_->Send(
-              new BlobHostMsg_AppendBlobDataItem(url, item));
+              new BlobHostMsg_AppendBlobDataItem(uuid_str, item));
         }
         break;
       case WebBlobData::Item::TypeBlob:
@@ -104,7 +74,7 @@ void WebBlobRegistryImpl::registerBlobURL(
               static_cast<uint64>(data_item.offset),
               static_cast<uint64>(data_item.length));
           sender_->Send(
-              new BlobHostMsg_AppendBlobDataItem(url, item));
+              new BlobHostMsg_AppendBlobDataItem(uuid_str, item));
         }
         break;
       case WebBlobData::Item::TypeURL:
@@ -118,7 +88,7 @@ void WebBlobRegistryImpl::registerBlobURL(
               static_cast<uint64>(data_item.length),
               base::Time::FromDoubleT(data_item.expectedModificationTime));
           sender_->Send(
-              new BlobHostMsg_AppendBlobDataItem(url, item));
+              new BlobHostMsg_AppendBlobDataItem(uuid_str, item));
         }
         break;
       default:
@@ -126,20 +96,87 @@ void WebBlobRegistryImpl::registerBlobURL(
     }
   }
   sender_->Send(new BlobHostMsg_FinishBuilding(
-      url, data.contentType().utf8().data()));
+      uuid_str, data.contentType().utf8().data()));
+}
+
+void WebBlobRegistryImpl::addBlobDataRef(const WebString& uuid) {
+  sender_->Send(new BlobHostMsg_IncrementRefCount(uuid.utf8()));
+}
+
+void WebBlobRegistryImpl::removeBlobDataRef(const WebString& uuid) {
+  sender_->Send(new BlobHostMsg_DecrementRefCount(uuid.utf8()));
+}
+
+void WebBlobRegistryImpl::registerPublicBlobURL(
+    const WebURL& url, const WebString& uuid) {
+  sender_->Send(new BlobHostMsg_RegisterPublicURL(url, uuid.utf8()));
+}
+
+void WebBlobRegistryImpl::revokePublicBlobURL(const WebURL& url) {
+  sender_->Send(new BlobHostMsg_RevokePublicURL(url));
+}
+
+void WebBlobRegistryImpl::SendDataForBlob(const std::string& uuid_str,
+                                          const WebThreadSafeData& data) {
+
+  if (data.size() == 0)
+    return;
+  if (data.size() < kLargeThresholdBytes) {
+    webkit_blob::BlobData::Item item;
+    item.SetToBytes(data.data(), data.size());
+    sender_->Send(new BlobHostMsg_AppendBlobDataItem(uuid_str, item));
+  } else {
+    // We handle larger amounts of data via SharedMemory instead of
+    // writing it directly to the IPC channel.
+    size_t shared_memory_size = std::min(
+        data.size(), kMaxSharedMemoryBytes);
+    scoped_ptr<base::SharedMemory> shared_memory(
+        ChildThread::AllocateSharedMemory(shared_memory_size,
+                                          sender_.get()));
+    CHECK(shared_memory.get());
+
+    size_t data_size = data.size();
+    const char* data_ptr = data.data();
+    while (data_size) {
+      size_t chunk_size = std::min(data_size, shared_memory_size);
+      memcpy(shared_memory->memory(), data_ptr, chunk_size);
+      sender_->Send(new BlobHostMsg_SyncAppendSharedMemory(
+          uuid_str, shared_memory->handle(), chunk_size));
+      data_size -= chunk_size;
+      data_ptr += chunk_size;
+    }
+  }
+}
+
+// DEPRECATED, almost. Until blink is updated, we implement these older methods
+// in terms of our newer blob storage system. We create a uuid for each 'data'
+// we see and construct a mapping from the private blob urls we're given to
+// that uuid. The mapping is maintained in the browser process.
+//
+// Chromium is setup to speak in terms of old-style private blob urls or
+// new-style uuid identifiers. Once blink has been migrated support for
+// the old-style will be deleted. Search for the term deprecated.
+
+void WebBlobRegistryImpl::registerBlobURL(
+    const WebURL& url, WebBlobData& data) {
+  std::string uuid = base::GenerateGUID();
+  registerBlobData(WebKit::WebString::fromUTF8(uuid), data);
+  sender_->Send(new BlobHostMsg_DeprecatedRegisterBlobURL(url, uuid));
+  sender_->Send(new BlobHostMsg_DecrementRefCount(uuid));

[ericu, 2013/08/21 23:26:09]

Why decrement the refcount here?

[michaeln, 2013/08/27 23:24:06]

BlobHostMsg_DeprecatedRegisterBlobURL implicitly adds a ref. That ref is
balanced with the eventual BlobHostMsg_DeprecatedRevokeBlobURL two methods down.

 }
 
 void WebBlobRegistryImpl::registerBlobURL(
     const WebURL& url, const WebURL& src_url) {
-  DCHECK(ChildThread::current());
-  sender_->Send(new BlobHostMsg_Clone(url, src_url));
+  sender_->Send(new BlobHostMsg_DeprecatedCloneBlobURL(url, src_url));
 }
 
 void WebBlobRegistryImpl::unregisterBlobURL(const WebURL& url) {
-  DCHECK(ChildThread::current());
-  sender_->Send(new BlobHostMsg_Remove(url));
+  sender_->Send(new BlobHostMsg_DeprecatedRevokeBlobURL(url));
 }
 
+
+// ------ streams stuff -----
+
 void WebBlobRegistryImpl::registerStreamURL(
     const WebURL& url, const WebString& content_type) {
   DCHECK(ChildThread::current());