Blobs: Mechanism for creating Blobs in browser process, then transferring to renderer.

content/browser/fileapi/chrome_blob_storage_context.cc

 // Copyright (c) 2012 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/fileapi/chrome_blob_storage_context.h"
 
 #include "base/bind.h"
+#include "base/guid.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
+#include "webkit/browser/blob/blob_data_handle.h"
 #include "webkit/browser/blob/blob_storage_context.h"
 
 using base::UserDataAdapter;
 using webkit_blob::BlobStorageContext;
 
 namespace content {
 
+namespace {
+
+class BlobHandleImpl : public BlobHandle {
+ public:
+  BlobHandleImpl(scoped_ptr<webkit_blob::BlobDataHandle> handle)
+      : handle_(handle.Pass()) {
+  }
+
+  virtual ~BlobHandleImpl() {}
+
+  virtual std::string uuid() OVERRIDE {
+    return handle_->uuid();
+  }
+
+ private:
+  scoped_ptr<webkit_blob::BlobDataHandle> handle_;
+};
+
+}  // namespace
+
 static const char* kBlobStorageContextKeyName = "content_blob_storage_context";
 
 ChromeBlobStorageContext::ChromeBlobStorageContext() {}
 
 ChromeBlobStorageContext* ChromeBlobStorageContext::GetFor(
     BrowserContext* context) {
   if (!context->GetUserData(kBlobStorageContextKeyName)) {
     scoped_refptr<ChromeBlobStorageContext> blob =
         new ChromeBlobStorageContext();
     context->SetUserData(
         kBlobStorageContextKeyName,
         new UserDataAdapter<ChromeBlobStorageContext>(blob.get()));
     // Check first to avoid memory leak in unittests.
     if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
       BrowserThread::PostTask(
           BrowserThread::IO, FROM_HERE,
           base::Bind(&ChromeBlobStorageContext::InitializeOnIOThread, blob));
     }
   }
 
   return UserDataAdapter<ChromeBlobStorageContext>::Get(
       context, kBlobStorageContextKeyName);
 }
 
 void ChromeBlobStorageContext::InitializeOnIOThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   context_.reset(new BlobStorageContext());
 }
 
+void ChromeBlobStorageContext::CreateMemoryBackedBlob(
+    const char* data, size_t length, const BlobCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  BrowserThread::PostTaskAndReplyWithResult(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&ChromeBlobStorageContext::CreateMemoryBackedBlobOnIOThread,
+                 this, data, length, callback),
+      callback);
+}
+
 ChromeBlobStorageContext::~ChromeBlobStorageContext() {}
 
+scoped_ptr<BlobHandle>
+ChromeBlobStorageContext::CreateMemoryBackedBlobOnIOThread(
+    const char* data, size_t length, const BlobCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  std::string uuid(base::GenerateGUID());
+  scoped_refptr<webkit_blob::BlobData> blob_data =
+      new webkit_blob::BlobData(uuid);
+  blob_data->AppendData(data, length);
+  scoped_ptr<BlobHandle> blob_handle(
+      new BlobHandleImpl(context_->AddFinishedBlob(blob_data.get()).Pass()));

[michaeln, 2014/05/12 22:43:17]

AddFinishedBlob can return NULL is some cases, i think the public content API
method probably should when that happens as case well.

[tommycli, 2014/05/12 23:35:05]

Done.

+  return blob_handle.Pass();
+}
+
 void ChromeBlobStorageContext::DeleteOnCorrectThread() const {
   if (BrowserThread::IsMessageLoopValid(BrowserThread::IO) &&
       !BrowserThread::CurrentlyOn(BrowserThread::IO)) {
     BrowserThread::DeleteSoon(BrowserThread::IO, FROM_HERE, this);
     return;
   }
   delete this;
 }
 
 }  // namespace content