src/cobalt/loader/blob_fetcher.h

// Copyright 2016 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COBALT_LOADER_BLOB_FETCHER_H_
#define COBALT_LOADER_BLOB_FETCHER_H_

#include "base/memory/weak_ptr.h"
#include "cobalt/loader/fetcher.h"

namespace cobalt {
namespace loader {

// For fetching the 'blob:' scheme.
class BlobFetcher : public Fetcher {
 public:
  // This callback avoids a dependency from the fetcher to the actual blob
  // implementation.
  // If the blob is successfully fetched:
  //   1. Writes the size of its buffer to |size|.
  //   2. If |size| > 0, then it also writes the address of the non-empty buffer
  //      to |data|, otherwise writes NULL to |data|.
  //   3. Returns true.
  // If the fetch fails:
  //   1. Writes 0 to |size|
  //   2. Writes NULL to |data|
  //   3. Returns false.
  typedef base::Callback<bool(const GURL& url, const char** data, size_t* size)>
      ResolverCallback;

  explicit BlobFetcher(const GURL& url, Handler* handler,
                       const ResolverCallback& resolver_callback);

  void Fetch();

  ~BlobFetcher() override;

 private:
  void GetData();

  GURL url_;
  ResolverCallback resolver_callback_;
  base::WeakPtrFactory<BlobFetcher> weak_ptr_factory_;
};

}  // namespace loader
}  // namespace cobalt

#endif  // COBALT_LOADER_BLOB_FETCHER_H_