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/*
* Copyright (C) 2010 The Android Open Source Project
*
* 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.
*/
#pragma once
#include <android-base/unique_fd.h>
#include <binder/Parcelable.h>
#include <utils/Errors.h>
namespace android {
class Parcel;
namespace gui {
class BitTube : public Parcelable {
public:
// creates an uninitialized BitTube (to unparcel into)
BitTube() = default;
// creates a BitTube with a a specified send and receive buffer size
explicit BitTube(size_t bufsize);
// creates a BitTube with a default (4KB) send buffer
struct DefaultSizeType {};
static constexpr DefaultSizeType DefaultSize{};
explicit BitTube(DefaultSizeType);
explicit BitTube(const Parcel& data);
virtual ~BitTube() = default;
// check state after construction
status_t initCheck() const;
// get receive file-descriptor
int getFd() const;
// get the send file-descriptor.
int getSendFd() const;
// moves the receive file descriptor out of this BitTube
base::unique_fd moveReceiveFd();
// resets this BitTube's receive file descriptor to receiveFd
void setReceiveFd(base::unique_fd&& receiveFd);
// resets this BitTube's send file descriptor to sendFd
void setSendFd(base::unique_fd&& sendFd);
// send objects (sized blobs). All objects are guaranteed to be written or the call fails.
template <typename T>
static ssize_t sendObjects(BitTube* tube, T const* events, size_t count) {
return sendObjects(tube, events, count, sizeof(T));
}
// receive objects (sized blobs). If the receiving buffer isn't large enough, excess messages
// are silently discarded.
template <typename T>
static ssize_t recvObjects(BitTube* tube, T* events, size_t count) {
return recvObjects(tube, events, count, sizeof(T));
}
// implement the Parcelable protocol. Only parcels the receive file descriptor
status_t writeToParcel(Parcel* reply) const;
status_t readFromParcel(const Parcel* parcel);
private:
void init(size_t rcvbuf, size_t sndbuf);
// send a message. The write is guaranteed to send the whole message or fail.
ssize_t write(void const* vaddr, size_t size);
// receive a message. the passed buffer must be at least as large as the write call used to send
// the message, excess data is silently discarded.
ssize_t read(void* vaddr, size_t size);
mutable base::unique_fd mSendFd;
mutable base::unique_fd mReceiveFd;
static ssize_t sendObjects(BitTube* tube, void const* events, size_t count, size_t objSize);
static ssize_t recvObjects(BitTube* tube, void* events, size_t count, size_t objSize);
};
} // namespace gui
} // namespace android
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