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// Copyright 2018 The Fuchsia 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 <lib/fidl/cpp/builder.h>
#include <lib/fidl/cpp/message.h>
#include <lib/fidl/cpp/message_buffer.h>
#include <stdint.h>
#include <zircon/fidl.h>
#include <zircon/types.h>
namespace fidl {
// A builder for FIDL messages that owns the memory for the message.
// A |MessageBuilder| is a |Builder| that uses the heap to back the memory for
// the message. If you wish to manage the memory yourself, you can use |Builder|
// and |Message| directly.
// Upon creation, the |MessageBuilder| creates a FIDL message header, which you
// can modify using |header()|.
class MessageBuilder : public Builder {
// Creates a |MessageBuilder| for the given |type| that allocates buffers
// for message of the given capacities.
// The bytes buffer is initialied by adding a |fidl_message_header_t|
// header.
// The buffers are freed when the |MessageBuilder| is destructed.
explicit MessageBuilder(const fidl_type_t* type,
uint32_t bytes_capacity = ZX_CHANNEL_MAX_MSG_BYTES,
uint32_t handles_capacity = ZX_CHANNEL_MAX_MSG_HANDLES);
// The memory that backs the message is freed by this destructor.
// The type of the message payload this object is building.
const fidl_type_t* type() const { return type_; }
// The header for the message.
// The message header is allocated by the |MessageBuilder| itself.
fidl_message_header_t* header() const {
return reinterpret_cast<fidl_message_header_t*>(buffer());
// Encodes a message of the given |type|.
// The memory that backs the message returned by this function is owned by
// the |MessageBuilder|, which means the |MessageBuilder| must remain alive
// as long as the |Message| object is in use.
// The |message| parameter might be modified even if this method returns an
// error.
zx_status_t Encode(Message* message_out, const char** error_msg_out);
// Resets all the data in the |MessageBuffer|.
// The underlying buffer is retained and reused. The next object will be
// allocated at the start of the buffer.
void Reset();
const fidl_type_t* type_;
MessageBuffer buffer_;
} // namespace fidl