[BlobAsync] Patch 2: Common Constants

storage/common/blob_storage/blob_item_bytes_request.h

+// Copyright 2015 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.
+
+#ifndef STORAGE_COMMON_BLOB_STORAGE_BLOB_ITEM_BYTES_REQUEST_H_
+#define STORAGE_COMMON_BLOB_STORAGE_BLOB_ITEM_BYTES_REQUEST_H_
+
+#include <stdint.h>
+#include <ostream>
+
+#include "base/basictypes.h"
+#include "storage/common/blob_storage/blob_storage_constants.h"
+#include "storage/common/storage_common_export.h"
+
+namespace storage {
+
+// This class is serialized over IPC to request bytes from a blob item.
+struct STORAGE_COMMON_EXPORT BlobItemBytesRequest {
+  // Not using std::numeric_limits<T>::max() because of non-C++11 builds.
+  static const size_t kInvalidIndex = SIZE_MAX;
+  static const uint64_t kInvalidSize = kuint64max;
+
+  static BlobItemBytesRequest CreateIPCRequest(size_t request_number,
+                                               size_t renderer_item_index,
+                                               size_t renderer_item_offset,
+                                               size_t size);
+
+  static BlobItemBytesRequest CreateSharedMemoryRequest(
+      size_t request_number,
+      size_t renderer_item_index,
+      size_t renderer_item_offset,
+      size_t size,
+      size_t handle_index,
+      uint64_t handle_offset);
+
+  static BlobItemBytesRequest CreateFileRequest(size_t request_number,
+                                                size_t renderer_item_index,
+                                                uint64_t renderer_item_offset,
+                                                uint64_t size,
+                                                size_t handle_index,
+                                                uint64_t handle_offset);
+
+  BlobItemBytesRequest();
+  BlobItemBytesRequest(size_t request_number,
+                       IPCBlobItemRequestStrategy transport_strategy,
+                       size_t renderer_item_index,
+                       uint64_t renderer_item_offset,
+                       uint64_t size,
+                       size_t handle_index,
+                       uint64_t handle_offset);
+  ~BlobItemBytesRequest();
+
+  // The request number uniquely identifies the memory request. We can't use
+  // the renderer item index or browser item index as there can be multiple
+  // requests for both (as segmentation boundaries can exist in both).
+  size_t request_number;
+  IPCBlobItemRequestStrategy transport_strategy;
+  size_t renderer_item_index;
+  uint64_t renderer_item_offset;
+  uint64_t size;
+  size_t handle_index;
+  uint64_t handle_offset;
+};
+
+STORAGE_COMMON_EXPORT void PrintTo(const BlobItemBytesRequest& request,
+                                   std::ostream* os);
+
+#if defined(UNIT_TEST)
+STORAGE_COMMON_EXPORT inline bool operator==(const BlobItemBytesRequest& a,
+                                             const BlobItemBytesRequest& b) {
+  return a.request_number == b.request_number &&
+         a.transport_strategy == b.transport_strategy &&
+         a.renderer_item_index == b.renderer_item_index &&
+         a.renderer_item_offset == b.renderer_item_offset && a.size == b.size &&
+         a.handle_index == b.handle_index && a.handle_offset == b.handle_offset;
+}
+
+STORAGE_COMMON_EXPORT inline bool operator!=(const BlobItemBytesRequest& a,
+                                             const BlobItemBytesRequest& b) {
+  return !(a == b);
+}
+#endif  // defined(UNIT_TEST)
+
+}  // namespace storage
+
+#endif  // STORAGE_COMMON_BLOB_STORAGE_BLOB_ITEM_BYTES_REQUEST_H_