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    // get the send file-descriptor.
52    int getSendFd() const;
53
54    // send objects (sized blobs). All objects are guaranteed to be written or the call fails.
55    template <typename T>
56    static ssize_t sendObjects(const sp<BitTube>& tube,
57            T const* events, size_t count) {
58        return sendObjects(tube, events, count, sizeof(T));
59    }
60
61    // receive objects (sized blobs). If the receiving buffer isn't large enough,
62    // excess messages are silently discarded.
63    template <typename T>
64    static ssize_t recvObjects(const sp<BitTube>& tube,
65            T* events, size_t count) {
66        return recvObjects(tube, events, count, sizeof(T));
67    }
68
69    // parcels this BitTube
70    status_t writeToParcel(Parcel* reply) const;
71
72private:
73    void init(size_t rcvbuf, size_t sndbuf);
74
75    // send a message. The write is guaranteed to send the whole message or fail.
76    ssize_t write(void const* vaddr, size_t size);
77
78    // receive a message. the passed buffer must be at least as large as the
79    // write call used to send the message, excess data is silently discarded.
80    ssize_t read(void* vaddr, size_t size);
81
82    int mSendFd;
83    mutable int mReceiveFd;
84
85    static ssize_t sendObjects(const sp<BitTube>& tube,
86            void const* events, size_t count, size_t objSize);
87
88    static ssize_t recvObjects(const sp<BitTube>& tube,
89            void* events, size_t count, size_t objSize);
90};
91
92// ----------------------------------------------------------------------------
93}; // namespace android
94
95#endif // ANDROID_GUI_SENSOR_CHANNEL_H
96