aboutsummaryrefslogtreecommitdiff
path: root/singleapplication.cpp
blob: 8dd94a8366c5eb005d09beb5eb0542a9846bf044 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
// The MIT License (MIT)
//
// Copyright (c) Itay Grudev 2015 - 2018
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include <QtCore/QTime>
#include <QtCore/QThread>
#include <QtCore/QDateTime>
#include <QtCore/QByteArray>
#include <QtCore/QSharedMemory>

#include "singleapplication.h"
#include "singleapplication_p.h"

/**
 * @brief Constructor. Checks and fires up LocalServer or closes the program
 * if another instance already exists
 * @param argc
 * @param argv
 * @param {bool} allowSecondaryInstances
 */
SingleApplication::SingleApplication( int &argc, char *argv[], bool allowSecondary, Options options, int timeout )
    : app_t( argc, argv ), d_ptr( new SingleApplicationPrivate( this ) )
{
    Q_D(SingleApplication);

    // Store the current mode of the program
    d->options = options;

    // Generating an application ID used for identifying the shared memory
    // block and QLocalServer
    d->genBlockServerName();

#ifdef Q_OS_UNIX
    // By explicitly attaching it and then deleting it we make sure that the
    // memory is deleted even after the process has crashed on Unix.
    d->memory = new QSharedMemory( d->blockServerName );
    d->memory->attach();
    delete d->memory;
#endif
    // Guarantee thread safe behaviour with a shared memory block.
    d->memory = new QSharedMemory( d->blockServerName );

    // Create a shared memory block
    if( d->memory->create( sizeof( InstancesInfo ) ) ) {
        // Initialize the shared memory block
        d->memory->lock();
        d->initializeMemoryBlock();
        d->memory->unlock();
    } else {
        // Attempt to attach to the memory segment
        if( ! d->memory->attach() ) {
            qCritical() << "SingleApplication: Unable to attach to shared memory block.";
            qCritical() << d->memory->errorString();
            delete d;
            ::exit( EXIT_FAILURE );
        }
    }

    InstancesInfo* inst = static_cast<InstancesInfo*>( d->memory->data() );
    QTime time;
    time.start();

    // Make sure the shared memory block is initialised and in consistent state
    while( true ) {
        d->memory->lock();

        if( d->blockChecksum() == inst->checksum ) break;

        if( time.elapsed() > 5000 ) {
            qWarning() << "SingleApplication: Shared memory block has been in an inconsistent state from more than 5s. Assuming primary instance failure.";
            d->initializeMemoryBlock();
        }

        d->memory->unlock();

        // Random sleep here limits the probability of a colision between two racing apps
        qsrand( QDateTime::currentMSecsSinceEpoch() % std::numeric_limits<uint>::max() );
        QThread::sleep( 8 + static_cast <unsigned long>( static_cast <float>( qrand() ) / RAND_MAX * 10 ) );
    }

    if( inst->primary == false) {
        d->startPrimary();
        d->memory->unlock();
        return;
    }

    // Check if another instance can be started
    if( allowSecondary ) {
        inst->secondary += 1;
        inst->checksum = d->blockChecksum();
        d->instanceNumber = inst->secondary;
        d->startSecondary();
        if( d->options & Mode::SecondaryNotification ) {
            d->connectToPrimary( timeout, SingleApplicationPrivate::SecondaryInstance );
        }
        d->memory->unlock();
        return;
    }

    d->memory->unlock();

    d->connectToPrimary( timeout, SingleApplicationPrivate::NewInstance );

    delete d;

    ::exit( EXIT_SUCCESS );
}

/**
 * @brief Destructor
 */
SingleApplication::~SingleApplication()
{
    Q_D(SingleApplication);
    delete d;
}

bool SingleApplication::isPrimary()
{
    Q_D(SingleApplication);
    return d->server != nullptr;
}

bool SingleApplication::isSecondary()
{
    Q_D(SingleApplication);
    return d->server == nullptr;
}

quint32 SingleApplication::instanceId()
{
    Q_D(SingleApplication);
    return d->instanceNumber;
}

qint64 SingleApplication::primaryPid()
{
    Q_D(SingleApplication);
    return d->primaryPid();
}

bool SingleApplication::sendMessage( QByteArray message, int timeout )
{
    Q_D(SingleApplication);

    // Nobody to connect to
    if( isPrimary() ) return false;

    // Make sure the socket is connected
    d->connectToPrimary( timeout,  SingleApplicationPrivate::Reconnect );

    d->socket->write( message );
    bool dataWritten = d->socket->flush();
    d->socket->waitForBytesWritten( timeout );
    return dataWritten;
}