android /system/vold源码分析(6)

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接着分析CommandListener，FrameworkListener是它的直接父类。
FrameworkListener类的代码：

class FrameworkListener : public SocketListener {public:    static const int CMD_ARGS_MAX = 26;    /* 1 out of errorRate will be dropped */    int errorRate;private:    int mCommandCount;    bool mWithSeq;    FrameworkCommandCollection *mCommands;public:    FrameworkListener(const char *socketName);    FrameworkListener(const char *socketName, bool withSeq);    virtual ~FrameworkListener() {}protected:    void registerCmd(FrameworkCommand *cmd);    virtual bool onDataAvailable(SocketClient *c);private:    void dispatchCommand(SocketClient *c, char *data);    void init(const char *socketName, bool withSeq);};

前面分析过了，当有数据到来时会调用onDataAvailalbe()方法：

bool FrameworkListener::onDataAvailable(SocketClient *c) {    char buffer[CMD_BUF_SIZE];    int len;    len = TEMP_FAILURE_RETRY(read(c->getSocket(), buffer, sizeof(buffer)));    if (len < 0) {        SLOGE("read() failed (%s)", strerror(errno));        return false;    } else if (!len)        return false;   if(buffer[len-1] != '\0')        SLOGW("String is not zero-terminated");    int offset = 0;    int i;    for (i = 0; i < len; i++) {        if (buffer[i] == '\0') { //可以有多条命令，它们之间使用\0分隔。            /* IMPORTANT: dispatchCommand() expects a zero-terminated string */            dispatchCommand(c, buffer + offset);            offset = i + 1;        }    }    return true;}

调用dispatchCommand:

void FrameworkListener::dispatchCommand(SocketClient *cli, char *data) {分析命令的代码略，最终得到argv    for (i = mCommands->begin(); i != mCommands->end(); ++i) {        FrameworkCommand *c = *i;        if (!strcmp(argv[0], c->getCommand())) {            if (c->runCommand(cli, argc, argv)) {                SLOGW("Handler '%s' error (%s)", c->getCommand(), strerror(errno));            }            goto out;        }    }    cli->sendMsg(500, "Command not recognized", false);

FrameworkCommand即是执行的命令。实际上在CommandListener的构造函数中即注册了多个命令：

CommandListener::CommandListener() :                 FrameworkListener("vold", true) {    registerCmd(new DumpCmd());    registerCmd(new VolumeCmd());    registerCmd(new AsecCmd());    registerCmd(new ObbCmd());    registerCmd(new StorageCmd());    registerCmd(new XwarpCmd());    registerCmd(new CryptfsCmd());    registerCmd(new FstrimCmd());}

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