比特币源码研读(8)-main函数(7)steemCreated with Sketch.

in #btc7 years ago

2)读取配置文件:读取配置文件,如果配置文件出错,则弹出错误提示框,并且程序退出

try

{

 gArgs.ReadConfigFile(gArgs.GetArg("-conf",BITCOIN_CONF_FILENAME));

}
catch (const std::exception&e)

{

 fprintf(stderr,"Error reading configuration file: %s\n",e.what());

 returnfalse;

}
该函数流程图如下:

1.png

分析1:BITCOIN_CONF_FILENAME,宏定义在util.cpp文件中,定义如下:

const char * const

BITCOIN_CONF_FILENAME = "bitcoin.conf";
bitcoin.conf是客户端的配置文件,位置是bitcoin/contrib/init,该文件定义了很多env,如下

env BITCOIND_BIN="/usr/bin/bitcoind"

env BITCOIND_USER="bitcoin"

env BITCOIND_GROUP="bitcoin"

env BITCOIND_PIDDIR="/var/run/bitcoind"

envBITCOIND_PIDFILE="/var/run/bitcoind/bitcoind.pid"

envBITCOIND_CONFIGFILE="/etc/bitcoin/bitcoin.conf"

env BITCOIND_DATADIR="/var/lib/bitcoind"

分析2:GetArg函数

2.png

由函数可以看出,如果找到conf文件,则用这个conf文件,如果没有找到,则用默认文件。

分析3:ReadConfigFile

voidArgsManager::ReadConfigFile(const std::string& confPath)

{

 fs::ifstream streamConfig(GetConfigFile(confPath));

 if (!streamConfig.good())

return; // No bitcoin.conf file is OK

{

LOCK(cs_args);

std::set setOptions;

setOptions.insert("*");

for(boost::program_options::detail::config_file_iterator it(streamConfig,setOptions), end; it != end; ++it)

{

// Don't overwrite existingsettings so command line settings override bitcoin.conf

std::string strKey =std::string("-") + it->string_key;

std::string strValue =it->value[0];

InterpretNegativeSetting(strKey,strValue);

if (mapArgs.count(strKey) == 0)

mapArgs[strKey] = strValue;

mapMultiArgs[strKey].push_back(strValue);

}
}
// If datadir is changed in .conf file:

ClearDatadirCache();

}
fs::ifstream把硬盘上的文件读取到内存中,定义一个文件流streamConfig

ifstream的详细解释见:http://www.cplusplus.com/reference/fstream/ifstream/

streamConfig读取的文件是GetConfigFile(confPath),我们再看看这个函数:

fs::pathGetConfigFile(const std::string& confPath)

{

fs::path pathConfigFile(confPath);

if (!pathConfigFile.is_complete())

pathConfigFile = GetDataDir(false) /pathConfigFile;

return pathConfigFile;

}
读取confPath,也就是BITCOIN_CONF_FILENAME文件,判断文件是否完整,如果不完整则读取默认的配置文件,GetDataDir函数见 比特币源码研读(7)-main函数(6)

紧接着就开始判断这个文件是否为conf文件,如果不是则直接退出

if(!streamConfig.good())

return; // No bitcoin.conf file is OK
如果判断文件正常,开始执行for循环,读取配置文件的信息,写到mapArgs和mapMultiArgs中。

最后,清空文件路径:函数最后是为防止配置文件中设置了数据目录参数datadir,通过ClearDatadirCache()函数将数据文件路径参数设置为空目录,这样下次进入GetDataDir()时,我们将会根据新的datadir创建数据目录。

// If datadir is changed in .conffile:

ClearDatadirCache();
////////////////////////读取配置文件函数分析完毕////////////////////

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