1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <android-base/unique_fd.h> 20 #include <binder/Parcelable.h> 21 #include <utils/Errors.h> 22 23 namespace android { 24 25 class Parcel; 26 27 namespace gui { 28 29 class BitTube : public Parcelable { 30 public: 31 // creates an uninitialized BitTube (to unparcel into) 32 BitTube() = default; 33 34 // creates a BitTube with a a specified send and receive buffer size 35 explicit BitTube(size_t bufsize); 36 37 // creates a BitTube with a default (4KB) send buffer 38 struct DefaultSizeType {}; 39 static constexpr DefaultSizeType DefaultSize{}; 40 explicit BitTube(DefaultSizeType); 41 42 explicit BitTube(const Parcel& data); 43 44 virtual ~BitTube() = default; 45 46 // check state after construction 47 status_t initCheck() const; 48 49 // get receive file-descriptor 50 int getFd() const; 51 52 // get the send file-descriptor. 53 int getSendFd() const; 54 55 // moves the receive file descriptor out of this BitTube 56 base::unique_fd moveReceiveFd(); 57 58 // resets this BitTube's receive file descriptor to receiveFd 59 void setReceiveFd(base::unique_fd&& receiveFd); 60 61 // send objects (sized blobs). All objects are guaranteed to be written or the call fails. 62 template <typename T> 63 static ssize_t sendObjects(BitTube* tube, T const* events, size_t count) { 64 return sendObjects(tube, events, count, sizeof(T)); 65 } 66 67 // receive objects (sized blobs). If the receiving buffer isn't large enough, excess messages 68 // are silently discarded. 69 template <typename T> 70 static ssize_t recvObjects(BitTube* tube, T* events, size_t count) { 71 return recvObjects(tube, events, count, sizeof(T)); 72 } 73 74 // implement the Parcelable protocol. Only parcels the receive file descriptor 75 status_t writeToParcel(Parcel* reply) const; 76 status_t readFromParcel(const Parcel* parcel); 77 78 private: 79 void init(size_t rcvbuf, size_t sndbuf); 80 81 // send a message. The write is guaranteed to send the whole message or fail. 82 ssize_t write(void const* vaddr, size_t size); 83 84 // receive a message. the passed buffer must be at least as large as the write call used to send 85 // the message, excess data is silently discarded. 86 ssize_t read(void* vaddr, size_t size); 87 88 base::unique_fd mSendFd; 89 mutable base::unique_fd mReceiveFd; 90 91 static ssize_t sendObjects(BitTube* tube, void const* events, size_t count, size_t objSize); 92 93 static ssize_t recvObjects(BitTube* tube, void* events, size_t count, size_t objSize); 94 }; 95 96 } // namespace gui 97 } // namespace android 98
