Analysis Redis source (b) redis-cli.c

1. int main ()

int main(int argc, char **argv) {
    int firstarg, j;
    char **argvcopy;
    struct redisCommand *rc;

    config.hostip = "127.0.0.1";
    config.hostport = 6379;

    firstarg = parseOptions(argc,argv);
    argc -= firstarg;
    argv += firstarg;
    
    /* Turn the plain C strings into Sds strings */
    argvcopy = zmalloc(sizeof(char*)*argc+1);
    for(j = 0; j < argc; j++)
        argvcopy[j] = sdsnew(argv[j]);

    if (argc < 1) {
        fprintf(stderr, "usage: redis-cli [-h host] [-p port] cmd arg1 arg2 arg3 ... argN\n");
        fprintf(stderr, "usage: echo \"argN\" | redis-cli [-h host] [-p port] cmd arg1 arg2 ... arg(N-1)\n");
        fprintf(stderr, "\nIf a pipe from standard input is detected this data is used as last argument.\n\n");
        fprintf(stderr, "example: cat /etc/passwd | redis-cli set my_passwd\n");
        fprintf(stderr, "example: redis-cli get my_passwd\n");
        exit(1);
    }

    /* Read the last argument from stdandard input if needed */
    if ((rc = lookupCommand(argv[0])) != NULL) {
        if (rc->arity > 0 && argc == rc->arity-1) {
            sds lastarg = readArgFromStdin();
            argvcopy[argc] = lastarg;
            argc++;
        }
    }

    return cliSendCommand(argc, argvcopy);
}

2. parseOptions (int argc, char ** argv) that changes the ip and port

static int parseOptions(int argc, char **argv) {
    int i;

    for (i = 1; i < argc; i++) {
        int lastarg = i==argc-1;
        
        if (!strcmp(argv[i],"-h") && !lastarg) {
            char *ip = zmalloc(32);
            if (anetResolve(NULL,argv[i+1],ip) == ANET_ERR) {
                printf("Can't resolve %s\n", argv[i]);
                exit(1);
            }
            config.hostip = ip;
            i++;
        } else if (!strcmp(argv[i],"-p") && !lastarg) {
            config.hostport = atoi(argv[i+1]);
            i++;
        } else {
            break;
        }
    }
    return i;
}

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "anet.h"
#include "sds.h"
#include "adlist.h"
#include "zmalloc.h"

#define REDIS_CMD_INLINE 1
#define REDIS_CMD_BULK 2

#define REDIS_NOTUSED(V) ((void) V)

static struct config {
    char *hostip;
    int hostport;
} config;

struct redisCommand {
    char *name;
    int arity;
    int flags;
};

3. lookupCommand (char * name) Find command, the command lawful judge

static struct redisCommand *lookupCommand(char *name) {
    int j = 0;
    while(cmdTable[j].name != NULL) {
        if (!strcasecmp(name,cmdTable[j].name)) return &cmdTable[j];
        j++;
    }
    return NULL;
}

3.2 strcasecmp(name,cmdTable[j].name)

后面的版本把这个比较进行了处理，如SeT，GET等

3.1 redisCommand cmdTable[]

static struct redisCommand cmdTable[] = {
    {"get",2,REDIS_CMD_INLINE},
    {"set",3,REDIS_CMD_BULK},
    {"setnx",3,REDIS_CMD_BULK},
    {"del",-2,REDIS_CMD_INLINE},
    {"exists",2,REDIS_CMD_INLINE},
    {"incr",2,REDIS_CMD_INLINE},
    {"decr",2,REDIS_CMD_INLINE},
    {"rpush",3,REDIS_CMD_BULK},
    {"lpush",3,REDIS_CMD_BULK},
    {"rpop",2,REDIS_CMD_INLINE},
    {"lpop",2,REDIS_CMD_INLINE},
    {"llen",2,REDIS_CMD_INLINE},
    {"lindex",3,REDIS_CMD_INLINE},
    {"lset",4,REDIS_CMD_BULK},
    {"lrange",4,REDIS_CMD_INLINE},
    {"ltrim",4,REDIS_CMD_INLINE},
    {"lrem",4,REDIS_CMD_BULK},
    {"sadd",3,REDIS_CMD_BULK},
    {"srem",3,REDIS_CMD_BULK},
    {"smove",4,REDIS_CMD_BULK},
    {"sismember",3,REDIS_CMD_BULK},
    {"scard",2,REDIS_CMD_INLINE},
    {"spop",2,REDIS_CMD_INLINE},
    {"sinter",-2,REDIS_CMD_INLINE},
    {"sinterstore",-3,REDIS_CMD_INLINE},
    {"sunion",-2,REDIS_CMD_INLINE},
    {"sunionstore",-3,REDIS_CMD_INLINE},
    {"sdiff",-2,REDIS_CMD_INLINE},
    {"sdiffstore",-3,REDIS_CMD_INLINE},
    {"smembers",2,REDIS_CMD_INLINE},
    {"incrby",3,REDIS_CMD_INLINE},
    {"decrby",3,REDIS_CMD_INLINE},
    {"getset",3,REDIS_CMD_BULK},
    {"randomkey",1,REDIS_CMD_INLINE},
    {"select",2,REDIS_CMD_INLINE},
    {"move",3,REDIS_CMD_INLINE},
    {"rename",3,REDIS_CMD_INLINE},
    {"renamenx",3,REDIS_CMD_INLINE},
    {"keys",2,REDIS_CMD_INLINE},
    {"dbsize",1,REDIS_CMD_INLINE},
    {"ping",1,REDIS_CMD_INLINE},
    {"echo",2,REDIS_CMD_BULK},
    {"save",1,REDIS_CMD_INLINE},
    {"bgsave",1,REDIS_CMD_INLINE},
    {"shutdown",1,REDIS_CMD_INLINE},
    {"lastsave",1,REDIS_CMD_INLINE},
    {"type",2,REDIS_CMD_INLINE},
    {"flushdb",1,REDIS_CMD_INLINE},
    {"flushall",1,REDIS_CMD_INLINE},
    {"sort",-2,REDIS_CMD_INLINE},
    {"info",1,REDIS_CMD_INLINE},
    {"mget",-2,REDIS_CMD_INLINE},
    {"expire",3,REDIS_CMD_INLINE},
    {"ttl",2,REDIS_CMD_INLINE},
    {"slaveof",3,REDIS_CMD_INLINE},
    {"debug",-2,REDIS_CMD_INLINE},
    {NULL,0,0}
};

static int cliReadReply(int fd);

4. cliSendCommand(int argc, char **argv)

static int cliSendCommand(int argc, char **argv) {
    struct redisCommand *rc = lookupCommand(argv[0]);
    int fd, j, retval = 0;
    sds cmd = sdsempty();

    if (!rc) {
        fprintf(stderr,"Unknown command '%s'\n",argv[0]);
        return 1;
    }

    if ((rc->arity > 0 && argc != rc->arity) ||
        (rc->arity < 0 && argc < -rc->arity)) {
            fprintf(stderr,"Wrong cliConnect of arguments for '%s'\n",rc->name);
            return 1;
    }
    if ((fd = cliConnect()) == -1) return 1;

    /* Build the command to send */
    for (j = 0; j < argc; j++) {
        if (j != 0) cmd = sdscat(cmd," ");
        if (j == argc-1 && rc->flags & REDIS_CMD_BULK) {
            cmd = sdscatprintf(cmd,"%d",sdslen(argv[j]));
        } else {
            cmd = sdscatlen(cmd,argv[j],sdslen(argv[j]));
        }
    }
    cmd = sdscat(cmd,"\r\n");
    if (rc->flags & REDIS_CMD_BULK) {
        cmd = sdscatlen(cmd,argv[argc-1],sdslen(argv[argc-1]));
        cmd = sdscat(cmd,"\r\n");
    }
    anetWrite(fd,cmd,sdslen(cmd));
    retval = cliReadReply(fd);
    if (retval) {
        close(fd);
        return retval;
    }
    close(fd);
    return 0;
}

4.1 cliConnect(void)

static int cliConnect(void) {
    char err[ANET_ERR_LEN];
    int fd;

    fd = anetTcpConnect(err,config.hostip,config.hostport);
    if (fd == ANET_ERR) {
        fprintf(stderr,"Connect: %s\n",err);
        return -1;
    }
    anetTcpNoDelay(NULL,fd);
    return fd;
}

8.1 9.1 cliReadLine(int fd)

static sds cliReadLine(int fd) {
    sds line = sdsempty();

    while(1) {
        char c;
        ssize_t ret;

        ret = read(fd,&c,1);
        if (ret == -1) {
            sdsfree(line);
            return NULL;
        } else if ((ret == 0) || (c == '\n')) {
            break;
        } else {
            line = sdscatlen(line,&c,1);
        }
    }
    return sdstrim(line,"\r\n");
}

8 cliReadSingleLineReply(int fd)

static int cliReadSingleLineReply(int fd) {
    sds reply = cliReadLine(fd);

    if (reply == NULL) return 1;
    printf("%s\n", reply);
    return 0;
}

9 cliReadBulkReply(int fd)

static int cliReadBulkReply(int fd) {
    sds replylen = cliReadLine(fd);
    char *reply, crlf[2];
    int bulklen;

    if (replylen == NULL) return 1;
    bulklen = atoi(replylen);
    if (bulklen == -1) {
        sdsfree(replylen);
        printf("(nil)");
        return 0;
    }
    reply = zmalloc(bulklen);
    anetRead(fd,reply,bulklen);
    anetRead(fd,crlf,2);
    if (bulklen && fwrite(reply,bulklen,1,stdout) == 0) {
        zfree(reply);
        return 1;
    }
    if (isatty(fileno(stdout)) && reply[bulklen-1] != '\n')
        printf("\n");
    zfree(reply);
    return 0;
}

cliReadMultiBulkReply(int fd)

static int cliReadMultiBulkReply(int fd) {
    sds replylen = cliReadLine(fd);
    int elements, c = 1;

    if (replylen == NULL) return 1;
    elements = atoi(replylen);
    if (elements == -1) {
        sdsfree(replylen);
        printf("(nil)\n");
        return 0;
    }
    if (elements == 0) {
        printf("(empty list or set)\n");
    }
    while(elements--) {
        printf("%d. ", c);
        if (cliReadReply(fd)) return 1;
        c++;
    }
    return 0;
}

cliReadReply(int fd)

static int cliReadReply(int fd) {
    char type;

    if (anetRead(fd,&type,1) <= 0) exit(1);
    switch(type) {
    case '-':
        printf("(error) ");
        cliReadSingleLineReply(fd);
        return 1;
    case '+':
    case ':':
        return cliReadSingleLineReply(fd);
    case '$':
        return cliReadBulkReply(fd);
    case '*':
        return cliReadMultiBulkReply(fd);
    default:
        printf("protocol error, got '%c' as reply type byte\n", type);
        return 1;
    }
}

readArgFromStdin(void)

static sds readArgFromStdin(void) {
    char buf[1024];
    sds arg = sdsempty();

    while(1) {
        int nread = read(fileno(stdin),buf,1024);

        if (nread == 0) break;
        else if (nread == -1) {
            perror("Reading from standard input");
            exit(1);
        }
        arg = sdscatlen(arg,buf,nread);
    }
    return arg;
}