blimp/engine/mojo/blob_channel.mojom

// Copyright 2016 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.

module blimp.engine.mojom;

// Exposes BlobChannel data producer methods to the renderer processes.
// The renderer can use this service to push bulk data such as images to
// the client.
interface BlobChannel {
  // Gets the list of cached BlobIDs and their replication status in the
  // browser process' BlobCache. The replication status is represented
  // as a boolean which, when true, indicates that the blob has been
  // sent to the client.
  // TODO(kmarshall): Add a delegate receiver to process cache invalidation
  // events from the browser as they occur.
  GetCachedBlobIds() => (map<string, bool> cache_state);

  // Stores the blob |id| in the BlobCache.
  // Because the IPC channel is a shared resource and payloads can be quite
  // large, we use shared memory to reduce channel contention and associated
  // latency with other components/features.
  //
  // The buffer is released when the callee discards the handle for |data|.
  PutBlob(string id, handle<shared_buffer> data, uint32 size);

  // Requests that the BlobChannel push the blob |id| over the wire.
  // The request will be ignored if the BlobChannel knows that
  // the client already has the data.
  DeliverBlob(string id);
};