QGC源码分析笔记一之main.cc

前言

一切的起源来自main()函数。

正文

main.cc源码如下

​

/****************************************************************************
 *
 *   (c) 2009-2016 QGROUNDCONTROL PROJECT 
 *
 * QGroundControl is licensed according to the terms in the file
 * COPYING.md in the root of the source code directory.
 *
 ****************************************************************************/


/**
 * @file
 *   @brief Main executable
 *   @author Lorenz Meier 
 *
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "QGCApplication.h"
#include "AppMessages.h"

#ifndef __mobile__
    #include "QGCSerialPortInfo.h"
    #include "RunGuard.h"
#endif

#ifdef UNITTEST_BUILD
    #include "UnitTest.h"
#endif

#ifdef QT_DEBUG
    #include "CmdLineOptParser.h"
    #ifdef Q_OS_WIN
        #include 
    #endif
#endif

#ifdef QGC_ENABLE_BLUETOOTH
#include 
#endif

#include 
#include "QGCMapEngine.h"

/* SDL does ugly things to main() */
#ifdef main
#undef main
#endif

#ifndef __mobile__
    Q_DECLARE_METATYPE(QGCSerialPortInfo)
#endif

#ifdef Q_OS_WIN

#include 

/// @brief CRT Report Hook installed using _CrtSetReportHook. We install this hook when
/// we don't want asserts to pop a dialog on windows.
int WindowsCrtReportHook(int reportType, char* message, int* returnValue)
{
    Q_UNUSED(reportType);

    std::cerr << message << std::endl;  // Output message to stderr
    *returnValue = 0;                   // Don't break into debugger
    return true;                        // We handled this fully ourselves
}

#endif

#if defined(__android__) && !defined(NO_SERIAL_LINK)
#include 
#include "qserialport.h"

jint JNI_OnLoad(JavaVM* vm, void* reserved)
{
    Q_UNUSED(reserved);

    JNIEnv* env;
    if (vm->GetEnv(reinterpret_cast(&env), JNI_VERSION_1_6) != JNI_OK) {
        return -1;
    }

    QSerialPort::setNativeMethods();

    return JNI_VERSION_1_6;
}
#endif

/**
 * @brief Starts the application
 *
 * @param argc Number of commandline arguments
 * @param argv Commandline arguments
 * @return exit code, 0 for normal exit and !=0 for error cases
 */

int main(int argc, char *argv[])
{
#ifndef __mobile__
    RunGuard guard("QGroundControlRunGuardKey");
    if (!guard.tryToRun()) {
        return 0;
    }
#endif

#ifdef Q_OS_UNIX
    //Force writing to the console on UNIX/BSD devices
    if (!qEnvironmentVariableIsSet("QT_LOGGING_TO_CONSOLE"))
        qputenv("QT_LOGGING_TO_CONSOLE", "1");
#endif

    // install the message handler
    AppMessages::installHandler();

#ifdef Q_OS_MAC
#ifndef __ios__
    // Prevent Apple's app nap from screwing us over
    // tip: the domain can be cross-checked on the command line with 
    QProcess::execute("defaults write org.qgroundcontrol.qgroundcontrol NSAppSleepDisabled -bool YES");
#endif
#endif

#ifdef Q_OS_WIN
    // Set our own OpenGL buglist
    qputenv("QT_OPENGL_BUGLIST", ":/opengl/resources/opengl/buglist.json");

    // Allow for command line override of renderer
    for (int i = 0; i < argc; i++) {
        const QString arg(argv[i]);
        if (arg == QStringLiteral("-angle")) {
            QCoreApplication::setAttribute(Qt::AA_UseOpenGLES);
            break;
        } else if (arg == QStringLiteral("-swrast")) {
            QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);
            break;
        }
    }
#endif

    // The following calls to qRegisterMetaType are done to silence debug output which warns
    // that we use these types in signals, and without calling qRegisterMetaType we can't queue
    // these signals. In general we don't queue these signals, but we do what the warning says
    // anyway to silence the debug output.
#ifndef NO_SERIAL_LINK
    qRegisterMetaType();
#endif
#ifdef QGC_ENABLE_BLUETOOTH
    qRegisterMetaType();
    qRegisterMetaType();
#endif
    qRegisterMetaType();
#ifndef __mobile__
    qRegisterMetaType();
#endif

    // We statically link our own QtLocation plugin

#ifdef Q_OS_WIN
    // In Windows, the compiler doesn't see the use of the class created by Q_IMPORT_PLUGIN
#pragma warning( disable : 4930 4101 )
#endif

    Q_IMPORT_PLUGIN(QGeoServiceProviderFactoryQGC)

    bool runUnitTests = false;          // Run unit tests

#ifdef QT_DEBUG
    // We parse a small set of command line options here prior to QGCApplication in order to handle the ones
    // which need to be handled before a QApplication object is started.

    bool stressUnitTests = false;       // Stress test unit tests
    bool quietWindowsAsserts = false;   // Don't let asserts pop dialog boxes

    QString unitTestOptions;
    CmdLineOpt_t rgCmdLineOptions[] = {
        { "--unittest",             &runUnitTests,          &unitTestOptions },
        { "--unittest-stress",      &stressUnitTests,       &unitTestOptions },
        { "--no-windows-assert-ui", &quietWindowsAsserts,   NULL },
        // Add additional command line option flags here
    };

    ParseCmdLineOptions(argc, argv, rgCmdLineOptions, sizeof(rgCmdLineOptions)/sizeof(rgCmdLineOptions[0]), false);
    if (stressUnitTests) {
        runUnitTests = true;
    }

    if (quietWindowsAsserts) {
#ifdef Q_OS_WIN
        _CrtSetReportHook(WindowsCrtReportHook);
#endif
    }

#ifdef Q_OS_WIN
    if (runUnitTests) {
        // Don't pop up Windows Error Reporting dialog when app crashes. This prevents TeamCity from
        // hanging.
        DWORD dwMode = SetErrorMode(SEM_NOGPFAULTERRORBOX);
        SetErrorMode(dwMode | SEM_NOGPFAULTERRORBOX);
    }
#endif
#endif // QT_DEBUG

    QGCApplication* app = new QGCApplication(argc, argv, runUnitTests);
    Q_CHECK_PTR(app);

#ifdef Q_OS_LINUX
    QApplication::setWindowIcon(QIcon(":/res/resources/icons/qgroundcontrol.ico"));
#endif /* Q_OS_LINUX */

    // There appears to be a threading issue in qRegisterMetaType which can cause it to throw a qWarning
    // about duplicate type converters. This is caused by a race condition in the Qt code. Still working
    // with them on tracking down the bug. For now we register the type which is giving us problems here
    // while we only have the main thread. That should prevent it from hitting the race condition later
    // on in the code.
    qRegisterMetaType > >();

    app->_initCommon();
    //-- Initialize Cache System
    getQGCMapEngine()->init();

    int exitCode = 0;

#ifdef UNITTEST_BUILD
    if (runUnitTests) {
        for (int i=0; i < (stressUnitTests ? 20 : 1); i++) {
            if (!app->_initForUnitTests()) {
                return -1;
            }

            // Run the test
            int failures = UnitTest::run(unitTestOptions);
            if (failures == 0) {
                qDebug() << "ALL TESTS PASSED";
                exitCode = 0;
            } else {
                qDebug() << failures << " TESTS FAILED!";
                exitCode = -failures;
                break;
            }
        }
    } else
#endif
    {
        if (!app->_initForNormalAppBoot()) {
            return -1;
        }
        exitCode = app->exec();
    }

    app->_shutdown();
    delete app;
    //-- Shutdown Cache System
    destroyMapEngine();

    qDebug() << "After app delete";

    return exitCode;
}


main.cc源码剖析如下：
/****************************************************************************
 *
 *   (c) 2009-2016 QGROUNDCONTROL PROJECT 
 *
 * QGroundControl is licensed according to the terms in the file
 * COPYING.md in the root of the source code directory.
 *
 ****************************************************************************/


/**
 * @file
 *   @brief Main executable
 *   @author Lorenz Meier 
 *
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "QGCApplication.h"
#include "AppMessages.h"

#ifndef __mobile__
    #include "QGCSerialPortInfo.h"
    #include "RunGuard.h"
#endif

#ifdef UNITTEST_BUILD
    #include "UnitTest.h"
#endif

#ifdef QT_DEBUG
    #include "CmdLineOptParser.h"
    #ifdef Q_OS_WIN
        #include 
    #endif
#endif

#ifdef QGC_ENABLE_BLUETOOTH
#include 
#endif

#include 
#include "QGCMapEngine.h"

/* SDL does ugly things to main() */
#ifdef main
#undef main
#endif

#ifndef __mobile__
    Q_DECLARE_METATYPE(QGCSerialPortInfo)
#endif

#ifdef Q_OS_WIN

#include 

/// @brief CRT Report Hook installed using _CrtSetReportHook. We install this hook when
/// we don't want asserts to pop a dialog on windows.
int WindowsCrtReportHook(int reportType, char* message, int* returnValue)
{
    Q_UNUSED(reportType);

    std::cerr << message << std::endl;  // Output message to stderr
    *returnValue = 0;                   // Don't break into debugger
    return true;                        // We handled this fully ourselves
}

#endif

#if defined(__android__) && !defined(NO_SERIAL_LINK)
#include 
#include "qserialport.h"

jint JNI_OnLoad(JavaVM* vm, void* reserved)
{
    Q_UNUSED(reserved);

    JNIEnv* env;
    if (vm->GetEnv(reinterpret_cast(&env), JNI_VERSION_1_6) != JNI_OK) {
        return -1;
    }

    QSerialPort::setNativeMethods();

    return JNI_VERSION_1_6;
}
#endif

[点击并拖拽以移动]
​

main.cc源码剖析如下：

/****************************************************************************
 *
 *   (c) 2009-2016 QGROUNDCONTROL PROJECT 
 *
 * QGroundControl is licensed according to the terms in the file
 * COPYING.md in the root of the source code directory.
 *
 ****************************************************************************/


/**
 * @file
 *   @brief Main executable
 *   @author Lorenz Meier 
 *
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "QGCApplication.h"
#include "AppMessages.h"

#ifndef __mobile__
    #include "QGCSerialPortInfo.h"
    #include "RunGuard.h"
#endif

#ifdef UNITTEST_BUILD
    #include "UnitTest.h"
#endif

#ifdef QT_DEBUG
    #include "CmdLineOptParser.h"
    #ifdef Q_OS_WIN
        #include 
    #endif
#endif

#ifdef QGC_ENABLE_BLUETOOTH
#include 
#endif

#include 
#include "QGCMapEngine.h"

/* SDL does ugly things to main() */
#ifdef main
#undef main
#endif

#ifndef __mobile__
    Q_DECLARE_METATYPE(QGCSerialPortInfo)
#endif

#ifdef Q_OS_WIN

#include 

/// @brief CRT Report Hook installed using _CrtSetReportHook. We install this hook when
/// we don't want asserts to pop a dialog on windows.
int WindowsCrtReportHook(int reportType, char* message, int* returnValue)
{
    Q_UNUSED(reportType);

    std::cerr << message << std::endl;  // Output message to stderr
    *returnValue = 0;                   // Don't break into debugger
    return true;                        // We handled this fully ourselves
}

#endif

#if defined(__android__) && !defined(NO_SERIAL_LINK)
#include 
#include "qserialport.h"

jint JNI_OnLoad(JavaVM* vm, void* reserved)
{
    Q_UNUSED(reserved);

    JNIEnv* env;
    if (vm->GetEnv(reinterpret_cast(&env), JNI_VERSION_1_6) != JNI_OK) {
        return -1;
    }

    QSerialPort::setNativeMethods();

    return JNI_VERSION_1_6;
}
#endif

【以上都是跨平台相关处理】

 

/**
 * @brief Starts the application
 *
 * @param argc Number of commandline arguments
 * @param argv Commandline arguments
 * @return exit code, 0 for normal exit and !=0 for error cases
 */

【进入正题 main】

 

int main(int argc, char *argv[]) 
{

【移动平台运行互斥管理 ：通过共享内存方式来进行程序互斥操作 】

【相关类如下：】

【共享内存：QSharedMemory 】

【信号量：QSystemSemaphore 】

#ifndef __mobile__
    RunGuard guard("QGroundControlRunGuardKey");
    if (!guard.tryToRun()) {
        return 0;
    }
#endif

【对于unix平台强制写入console控制台】

#ifdef Q_OS_UNIX
    //Force writing to the console on UNIX/BSD devices
    if (!qEnvironmentVariableIsSet("QT_LOGGING_TO_CONSOLE"))
        qputenv("QT_LOGGING_TO_CONSOLE", "1");
#endif

【注册消息处理程序】

    // install the message handler
    AppMessages::installHandler();

【MAC系统进行的特殊命令输入 NSAppSleepDisabled相关】

#ifdef Q_OS_MAC
#ifndef __ios__
    // Prevent Apple's app nap from screwing us over
    // tip: the domain can be cross-checked on the command line with 
    QProcess::execute("defaults write org.qgroundcontrol.qgroundcontrol NSAppSleepDisabled -bool YES");
#endif
#endif

【windows系统中OpenGLbuglist设置和OpenGL类型设置】

#ifdef Q_OS_WIN
    // Set our own OpenGL buglist
    qputenv("QT_OPENGL_BUGLIST", ":/opengl/resources/opengl/buglist.json");

    // Allow for command line override of renderer
    for (int i = 0; i < argc; i++) {
        const QString arg(argv[i]);
        if (arg == QStringLiteral("-angle")) {
            QCoreApplication::setAttribute(Qt::AA_UseOpenGLES);
            break;
        } else if (arg == QStringLiteral("-swrast")) {
            QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);
            break;
        }
    }
#endif

【以下是注册一些类型 枚举之类的到QML中使用】
 

    // The following calls to qRegisterMetaType are done to silence debug output which warns
    // that we use these types in signals, and without calling qRegisterMetaType we can't queue
    // these signals. In general we don't queue these signals, but we do what the warning says
    // anyway to silence the debug output.
#ifndef NO_SERIAL_LINK
    qRegisterMetaType();
#endif
#ifdef QGC_ENABLE_BLUETOOTH
    qRegisterMetaType();
    qRegisterMetaType();
#endif
    qRegisterMetaType();
#ifndef __mobile__
    qRegisterMetaType();
#endif

// We statically link our own QtLocation plugin

【去除windows警告 4930 4101】

#ifdef Q_OS_WIN
    // In Windows, the compiler doesn't see the use of the class created by Q_IMPORT_PLUGIN
#pragma warning( disable : 4930 4101 )
#endif

【引入静态插件 QGeoServiceProviderFactoryQGC】

Q_IMPORT_PLUGIN(QGeoServiceProviderFactoryQGC)

【是否运行单元测试】

【可以学习下ParseCmdLineOptions解析arg参数】

【_CrtSetReportHook进行hook】

bool runUnitTests = false; // Run unit tests

【DEBUG模式下进行的一些参数设置】

#ifdef QT_DEBUG
    // We parse a small set of command line options here prior to QGCApplication in order to handle the ones
    // which need to be handled before a QApplication object is started.

    bool stressUnitTests = false;       // Stress test unit tests
    bool quietWindowsAsserts = false;   // Don't let asserts pop dialog boxes

    QString unitTestOptions;
    CmdLineOpt_t rgCmdLineOptions[] = {
        { "--unittest",             &runUnitTests,          &unitTestOptions },
        { "--unittest-stress",      &stressUnitTests,       &unitTestOptions },
        { "--no-windows-assert-ui", &quietWindowsAsserts,   NULL },
        // Add additional command line option flags here
    };

    ParseCmdLineOptions(argc, argv, rgCmdLineOptions, sizeof(rgCmdLineOptions)/sizeof(rgCmdLineOptions[0]), false);
    if (stressUnitTests) {
        runUnitTests = true;
    }

    if (quietWindowsAsserts) {
#ifdef Q_OS_WIN
        _CrtSetReportHook(WindowsCrtReportHook);
#endif
    }

#ifdef Q_OS_WIN
    if (runUnitTests) {
        // Don't pop up Windows Error Reporting dialog when app crashes. This prevents TeamCity from
        // hanging.
        DWORD dwMode = SetErrorMode(SEM_NOGPFAULTERRORBOX);
        SetErrorMode(dwMode | SEM_NOGPFAULTERRORBOX);
    }
#endif
#endif // QT_DEBUG

【QGC App程序真正的入口地方 后面详谈】

【Q_CHECK_PTR宏 做了一个指针合法校验 很常用】

QGCApplication* app = new QGCApplication(argc, argv, runUnitTests); Q_CHECK_PTR(app);

【linux系统中app图标设置】

#ifdef Q_OS_LINUX
    QApplication::setWindowIcon(QIcon(":/res/resources/icons/qgroundcontrol.ico"));
#endif /* Q_OS_LINUX */

【防止qRegisterMetaType注册线程抛出异常特殊操作】

    // There appears to be a threading issue in qRegisterMetaType which can cause it to throw a qWarning
    // about duplicate type converters. This is caused by a race condition in the Qt code. Still working
    // with them on tracking down the bug. For now we register the type which is giving us problems here
    // while we only have the main thread. That should prevent it from hitting the race condition later
    // on in the code.
    qRegisterMetaType > >();

【QGC app 注册C++类到QML元对象中给QML使用】

app->_initCommon();

【初始化QGC地图引擎】

【就是个全局函数： extern QGCMapEngine* getQGCMapEngine();】

 //-- Initialize Cache System
    getQGCMapEngine()->init();

【退出返回code定义和最上面main开头注释呼应】

int exitCode = 0;

【单元测试参数设置】

#ifdef UNITTEST_BUILD
    if (runUnitTests) {
        for (int i=0; i < (stressUnitTests ? 20 : 1); i++) {
            if (!app->_initForUnitTests()) {
                return -1;
            }

            // Run the test
            int failures = UnitTest::run(unitTestOptions);
            if (failures == 0) {
                qDebug() << "ALL TESTS PASSED";
                exitCode = 0;
            } else {
                qDebug() << failures << " TESTS FAILED!";
                exitCode = -failures;
                break;
            }
        }
    } else
#endif

【_initForNormalAppBoot 初始化MainWindow主界面以及相关硬件设备 遥感之类的 最后同步Settings配置文件】

【剩下的都是些收尾工作 最后返回 exitCode】

【后续详细分析 _initForNormalAppBoot 】

【整个程序就运行起来了~】

【接下来就开始分析内部原理】

{
        if (!app->_initForNormalAppBoot()) {
            return -1;
        }
        exitCode = app->exec();
    }

    app->_shutdown();
    delete app;
    //-- Shutdown Cache System
    destroyMapEngine();

    qDebug() << "After app delete";

    return exitCode;
}

 

总结

直接分析main.cc结构还是很清晰的 基本流程如下图 （省去部分配置设置）