BitTube.h revision 90ed3e8d7883d9c80fb8bf11b1c593bd8b2b39d0
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#ifndef ANDROID_GUI_SENSOR_CHANNEL_H
18#define ANDROID_GUI_SENSOR_CHANNEL_H
19
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <utils/Errors.h>
24#include <utils/RefBase.h>
25#include <cutils/log.h>
26
27
28namespace android {
29// ----------------------------------------------------------------------------
30class Parcel;
31
32class BitTube : public RefBase
33{
34public:
35
36    // creates a BitTube with a default (4KB) send buffer
37    BitTube();
38
39    // creates a BitTube with a a specified send and receive buffer size
40    explicit BitTube(size_t bufsize);
41
42    explicit BitTube(const Parcel& data);
43    virtual ~BitTube();
44
45    // check state after construction
46    status_t initCheck() const;
47
48    // get receive file-descriptor
49    int getFd() const;
50
51    // send objects (sized blobs). All objects are guaranteed to be written or the call fails.
52    template <typename T>
53    static ssize_t sendObjects(const sp<BitTube>& tube,
54            T const* events, size_t count) {
55        return sendObjects(tube, events, count, sizeof(T));
56    }
57
58    // receive objects (sized blobs). If the receiving buffer isn't large enough,
59    // excess messages are silently discarded.
60    template <typename T>
61    static ssize_t recvObjects(const sp<BitTube>& tube,
62            T* events, size_t count) {
63        return recvObjects(tube, events, count, sizeof(T));
64    }
65
66    // parcels this BitTube
67    status_t writeToParcel(Parcel* reply) const;
68
69private:
70    void init(size_t rcvbuf, size_t sndbuf);
71
72    // send a message. The write is guaranteed to send the whole message or fail.
73    ssize_t write(void const* vaddr, size_t size);
74
75    // receive a message. the passed buffer must be at least as large as the
76    // write call used to send the message, excess data is silently discarded.
77    ssize_t read(void* vaddr, size_t size);
78
79    int mSendFd;
80    mutable int mReceiveFd;
81
82    static ssize_t sendObjects(const sp<BitTube>& tube,
83            void const* events, size_t count, size_t objSize);
84
85    static ssize_t recvObjects(const sp<BitTube>& tube,
86            void* events, size_t count, size_t objSize);
87};
88
89// ----------------------------------------------------------------------------
90}; // namespace android
91
92#endif // ANDROID_GUI_SENSOR_CHANNEL_H
93