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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.
#ifndef SRC_DEVICES_BIN_DRIVER_HOST_FIDL_TXN_H_
#define SRC_DEVICES_BIN_DRIVER_HOST_FIDL_TXN_H_
#include <lib/fidl/epitaph.h>
#include <lib/fidl/llcpp/message.h>
#include <lib/fidl/llcpp/transaction.h>
#include <lib/zx/channel.h>
#include <zircon/fidl.h>
// Manages state of a FIDL transaction for the DevMgr so we can reply to the correct message.
// DevmgrFidlTxn must not outlive the channel it is given
class DevmgrFidlTxn : public fidl::Transaction {
public:
DevmgrFidlTxn(zx::unowned_channel channel, uint32_t txid)
: channel_(channel), txid_(txid), status_called_(false) {}
DevmgrFidlTxn(const zx::channel& channel, uint32_t txid)
: channel_(channel), txid_(txid), status_called_(false) {}
~DevmgrFidlTxn() {
ZX_ASSERT_MSG(status_called_,
"DevmgrFidlTxn must have it's Status() method used. \
This provides Devmgr with the correct status value.\n");
}
zx_status_t Reply(fidl::OutgoingMessage* message) override {
ZX_ASSERT_MSG(txid_, "DevmgrFidlTxn must have its transaction id set.\n");
auto hdr = reinterpret_cast<fidl_message_header_t*>(message->bytes());
hdr->txid = txid_;
message->Write(channel_->get());
return message->status();
}
void Close(zx_status_t close_status) override {
// no-op for devmgr
}
std::unique_ptr<Transaction> TakeOwnership() override {
// status isn't called, but not relevant in a Async context
status_called_ = true;
return std::make_unique<DevmgrFidlTxn>(std::move(*this));
}
zx_status_t Status() __WARN_UNUSED_RESULT {
status_called_ = true;
return status_;
}
private:
// Reply channel
const zx::unowned_channel channel_;
// Transaction id of the message we're replying to
const uint32_t txid_;
// Has the Status method been called?
bool status_called_;
// Status is OK by default since not all functions call Reply
zx_status_t status_ = ZX_OK;
};
// Manages state of a FIDL transaction so we can reply to the correct message.
// FidlTxn must not outlive the channel it is given
class FidlTxn {
public:
FidlTxn(zx::unowned_channel channel, uint32_t txid) : channel_(channel), txid_(txid) {}
FidlTxn(const zx::channel& channel, uint32_t txid) : channel_(channel), txid_(txid) {}
FidlTxn& operator=(const FidlTxn&) = delete;
FidlTxn(const FidlTxn&) = delete;
FidlTxn& operator=(FidlTxn&&) = delete;
FidlTxn(FidlTxn&&) = delete;
zx_status_t Reply(const fidl_outgoing_msg_t* msg) {
auto hdr = static_cast<fidl_message_header_t*>(msg->bytes);
hdr->txid = txid_;
return channel_->write(0, msg->bytes, msg->num_bytes, msg->handles, msg->num_handles);
}
static zx_status_t FidlReply(fidl_txn_t* reply, const fidl_outgoing_msg_t* msg) {
static_assert(offsetof(FidlTxn, txn_) == 0);
return reinterpret_cast<FidlTxn*>(reply)->Reply(msg);
}
fidl_txn_t* fidl_txn() { return &txn_; }
private:
// Due to the implementation of FidlReply, it is important that this be the
// first member variable.
fidl_txn_t txn_ = {.reply = FidlTxn::FidlReply};
// Reply channel
const zx::unowned_channel channel_;
// Transaction id of the message we're replying to
const uint32_t txid_;
};
#endif // SRC_DEVICES_BIN_DRIVER_HOST_FIDL_TXN_H_