log4cplus 1.2.1 源码解析

log4cplus是C++轻量日志库，支持多个平台。

源码可从以下地址下载：

https://sourceforge.net/projects/log4cplus/

GitHub - log4cplus/log4cplus: log4cplus is a simple to use C++ logging API providing thread-safe, flexible, and arbitrarily granular control over log management and configuration. It is modelled after the Java log4j API.

DllMain

log4cplus::thread_callback DLL_PROCESS_ATTACH

queueLog4cplusInitializationThroughAPC

QueueUserAPC (initializeLog4cplusApcProc, GetCurrentThread (), 0)

initializeLog4cplusApcProc 异步调用

1.1 initializeLog4cplus (); 1.2 threadSetup ();

initializeLog4cplus+

internal::tls_storage_key = thread::impl::tls_init (ptd_cleanup_func) 获取tls索引

threadSetup ()+

internal::get_ptd (true) 获取TLS槽中的值，如果为空

alloc_ptd () 创建per_thread_data，并将其指针传入到tls索引对应的槽中

threadSetup ()-

DefaultContext * dc = get_dc (true)

如果default_context为空，

alloc_dc ()创建DefaultContext，设置default_context_state的值为DC_INITIALIZED

dc->TTCCLayout_time_base 设置时间

Logger::getRoot()

getDefaultHierarchy ().getRoot () default_context->hierarchy.root

initializeFactoryRegistry()+

reg = default_context->appender_factory_registry

DisableFactoryLockingspi::AppenderFactoryRegistry dfl_reg (reg) 传入reg._enableLocking false

LOG4CPLUS_REG_APPENDER (reg, ConsoleAppender) 宏展开：

reg.put(std::auto_ptr<log4cplus::spi::AppenderFactory>(new log4cplus::spi::FactoryTempl<log4cplus::ConsoleAppender, log4cplus::spi::AppenderFactory> (L"log4cplus::" L"ConsoleAppender")))

类似的，向default_context->appender_factory_registry中依次注册NullAppender，FileAppender，RollingFileAppender，DailyRollingFileAppender，TimeBasedRollingFileAppender，SocketAppender，NTEventLogAppender，Win32ConsoleAppender，Win32DebugAppender，SysLogAppender，AsyncAppender，Log4jUdpAppender

reg2 = default_context->layout_factory_registry`
​
LOG4CPLUS_REG_LAYOUT (reg2, SimpleLayout);`
​
    reg2.put(std::auto_ptr<log4cplus::spi::LayoutFactory>(new log4cplus::spi::FactoryTempl<log4cplus::SimpleLayout, log4cplus::spi::LayoutFactory>(L"log4cplus::" L"SimpleLayout")))

类似的，向default_context->layout_factory_registry中依次注册TTCCLayout，PatternLayout

reg3 = default_context->filter_factory_registry
​
LOG4CPLUS_REG_FILTER (reg3, DenyAllFilter);
​
    reg3.put(std::auto_ptr<log4cplus::spi::FilterFactory>(new log4cplus::spi::FactoryTempl<log4cplus::spi::DenyAllFilter, log4cplus::spi::FilterFactory>(L"log4cplus::spi::" L"DenyAllFilter")))

类似的，向 default_context->filter_factory_registry中注册LogLevelMatchFilter，LogLevelRangeFilter，StringMatchFilter

reg4 = default_context->locale_factory_registry
​
LOG4CPLUS_REG_LOCALE (reg4, LOG4CPLUS_TEXT("GLOBAL"), spi::GlobalLocale);
​
    reg4.put(std::auto_ptr<log4cplus::spi::LocaleFactory>(new spi::GlobalLocale(L"GLOBAL")))

类似的，向 default_context->filter_factory_registry中注册UserLocale,ClassicLocale

initializeFactoryRegistry()-

initializeLog4cplus-

propertyconfig_test.exe

log4cplus::initialize ()

initializeLog4cplus()

LogLog::getLogLog()->setInternalDebugging(true);

default_context->loglog.debugEnabled=TriTrue

Logger root = Logger::getRoot(); default_context->hierarchy.root

PropertyConfigurator::doConfigure(L"log4cplus.properties")+

PropertyConfigurator tmp(file, h, flags) L"log4cplus.properties",default_context->hierarchy,0 +

properties(propertyFile, pcflag_to_pflags_encoding (f))+

pcflag_to_pflags_encoding(0) 获取utf8等编码方式，0表示未定义的编码

imbue_file_from_flags (file, flags) 处理编码方式，实际未处理

file.open(LOG4CPLUS_FSTREAM_PREFERED_FILE_NAME(inputFile).c_str(), std::ios::binary) 以二进制方式打开文件

init(file) 解析文件，将key和value存放到map中.如果文件中包含“include”字符，嵌套解析

properties(propertyFile, pcflag_to_pflags_encoding (f))-

init()+

replaceEnvironVariables() 将配置文件中的key val中有环境变量的字符，进行环境变量替换

properties = properties.getPropertySubset( LOG4CPLUS_TEXT("log4cplus.") ) 获取log4cplus.的子属性的key和val

init()-

PropertyConfigurator tmp(file, h, flags) L"log4cplus.properties",default_context->hierarchy,0 -

tmp.configure() +

查找配置是否包含configDebug，有则设置default_context->loglog.debugEnabled为true

查找配置是否包含quietMode，有则设置default_context->loglog.quietMode为true

查找配置是否包含quietMode，有则设置disable_override为true

initializeLog4cplus()

configureAppenders() +

helpers::Properties appenderProperties = properties.getPropertySubset(LOG4CPLUS_TEXT("appender.")) 查找配置中的appender子属性，保存到appenderProperties中

遍历子属性

if子属性不包含“.”,获取对应的值factoryName

spi::AppenderFactory* factory = spi::getAppenderFactoryRegistry().get(factoryName) 从default_context->appender_factory_registry中获取factoryName对应的对象指针

helpers::Properties props_subset = appenderProperties.getPropertySubset((*it) + LOG4CPLUS_TEXT(".")); 获取下一级子集属性

SharedAppenderPtr appender = factory->createObject(props_subset)

appender设置Name，存放到appenders[属性]中

configureAppenders() -

configureLoggers() +

configureLoggers(root,properties.getProperty(LOG4CPLUS_TEXT("rootLogger"))) 向PropertyConfigurator.h.root中添加"rootLogger"配置对应的appender
​
helpers::Properties loggerProperties = properties.getPropertySubset(LOG4CPLUS_TEXT("logger."));
std::vector<tstring> loggers = loggerProperties.propertyNames();`

it=loggers：遍历

Logger log = getLogger(*it); PropertyConfigurator.h. ***TODO细节待确认

configureLogger(log, loggerProperties.getProperty(*it))

configureLoggers() -

configureAdditivity()

appenders.clear () ??

PropertyConfigurator::doConfigure(L"log4cplus.properties")-

Logger fileCat = Logger::getInstance(LOG4CPLUS_TEXT("filelogger")); default_context->hierarchy.getInstance("filelogger")

LOG4CPLUS_WARN(root, LOG4CPLUS_TEXT("Testing....")) 宏展开：

__pragma (warning(push)) pragma (warning(disable:4127))
​
do {
    log4cplus::Logger const& _l = log4cplus::detail::macros_get_logger(root);   //_l <=>default_context->hierarchy.root
​
    if ((!!(_l.isEnabledFor(log4cplus::WARN_LOG_LEVEL)))) {
​
        log4cplus::tostringstream& _log4cplus_buf = log4cplus::detail::get_macro_body_oss(); //internal::get_ptd ()->macros_oss;clear_tostringstream (oss); 
​
        _log4cplus_buf << L"Testing...."; 
​
        log4cplus::detail::macro_forced_log(l, log4cplus::WARN_LOG_LEVEL, _log4cplus_buf.str(), "D:\\Work\\03_Doc\\Library\\log4cplus\\log4cplus-1.2.1\\tests\\propertyconfig_test\\main.cxx", 42, __FUNCSIG__);
​
    }
​
} while (0) 
​
__pragma (warning(pop))

clear_tostringstream (oss)

os.clear ();
os.str (internal::empty_str);
os.setf (default_flags);
os.fill (default_fill);
os.precision (default_precision);
os.width (default_width);
​
#if defined (LOG4CPLUS_WORKING_LOCALE)
    std::locale glocale = std::locale ();
    if (os.getloc () != glocale)
        os.imbue (glocale);
#endif // defined (LOG4CPLUS_WORKING_LOCALE)

macro_forced_log

macro_forced_log (log4cplus::Logger const & logger,
    log4cplus::LogLevel log_level, log4cplus::tstring const & msg,
    char const * filename, int line, char const * func)
{
    log4cplus::spi::InternalLoggingEvent & ev
        = internal::get_ptd ()->forced_log_ev;
    ev.setLoggingEvent (logger.getName (), log_level, msg, filename, line,
        func);
    logger.forcedLog (ev);
}

Logger::forcedLog =>LoggerImpl::forcedLog=>LoggerImpl::callAppenders

 int writes = 0;
 for(const LoggerImpl* c = this; c != NULL; c=c->parent.get()) {
     writes += c->appendLoopOnAppenders(event);
     if(!c->additive) {
         break;
     }
 }

AppenderAttachableImpl::appendLoopOnAppenders

thread::MutexGuard guard (appender_list_mutex);
​
for(ListType::const_iterator it=appenderList.begin();
    it!=appenderList.end();
    ++it)
{
    ++count;
    (*it)->doAppend(event);
}

控制台输出：

ConsoleAppender::append

thread::MutexGuard guard (getOutputMutex ());
​
tostream& output = (logToStdErr ? tcerr : tcout);
layout->formatAndAppend(output, event);
if(immediateFlush) {
    output.flush();
}

PatternLayout::formatAndAppend

for(PatternConverterList::iterator it=parsedPattern.begin();
    it!=parsedPattern.end();
    ++it)
{
    (*it)->formatAndAppend(output, event);
}

文件输出：

RollingFileAppender::append

if (useLockFile)
    out.seekp (0, std::ios_base::end);
​
// Rotate log file if needed before appending to it.
if (out.tellp() > maxFileSize)
    rollover(true);
​
FileAppender::append(event);
​
// Rotate log file if needed after appending to it.
if (out.tellp() > maxFileSize)
    rollover(true);

FileAppenderBase::append

if(!out.good()) {
    if(!reopen()) {
        getErrorHandler()->error(  LOG4CPLUS_TEXT("file is not open: ")
                                 + filename);
        return;
    }
    // Resets the error handler to make it
    // ready to handle a future append error.
    else
        getErrorHandler()->reset();
}
​
if (useLockFile)
    out.seekp (0, std::ios_base::end);
​
layout->formatAndAppend(out, event);
​
if(immediateFlush || useLockFile)
    out.flush();

PatternLayout::formatAndAppend

for(PatternConverterList::iterator it=parsedPattern.begin();
    it!=parsedPattern.end();
    ++it)
{
    (*it)->formatAndAppend(output, event);
}

对于使用Unicode编译，有中文输出的情况下，需要设置local

log4cplus.appender.rootLogger.Locale=chs

使用VS调试器，且log4cplus.appender.rootLogger.File中存在相对路径的情况下

log4cplus.appender.rootLogger.CreateDirs=true