linenoise

linenoise 用于创建交互式命令行界面，简化了用户输入的处理和历史记录的管理

https://github.com/antirez/linenoise

示例

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include "linenoise.h"

int main(int argc, char **argv)
{
    char *line;

    while (true)
    {
        line = linenoise("app> ");

        if (line == NULL || line[0] == 'q')
        {
            break;
        }

        printf("echo: '%s'\n", line);
        free(line);
    }
    return 0;
}

运行结果

gcc -o client mini-client.c linenoise.c && ./client

app> hello
echo: 'hello'
app> hi
echo: 'hi'
app> q

更复杂的示例

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include "linenoise.h"

void completion(const char *buf, linenoiseCompletions *lc)
{
    if (buf[0] == 'h')
    {
        linenoiseAddCompletion(lc, "hello");
        linenoiseAddCompletion(lc, "hello World");
    }
}

char *hints(const char *buf, int *color, int *bold)
{
    if (!strcasecmp(buf, "hello"))
    {
        *color = 35;
        *bold = 0;
        return " World";
    }
    return NULL;
}

int main(int argc, char **argv)
{
    char *line;
    char *prgname = argv[0];
    int async = 0;

    /* Parse options, with --multiline we enable multi line editing. */
    while (argc > 1)
    {
        argc--;
        argv++;
        if (!strcmp(*argv, "--multiline"))
        {
            linenoiseSetMultiLine(1);
            printf("Multi-line mode enabled.\n");
        }
        else if (!strcmp(*argv, "--keycodes"))
        {
            linenoisePrintKeyCodes();
            exit(0);
        }
        else if (!strcmp(*argv, "--async"))
        {
            async = 1;
        }
        else
        {
            fprintf(stderr, "Usage: %s [--multiline] [--keycodes] [--async]\n", prgname);
            exit(1);
        }
    }

    /* Set the completion callback. This will be called every time the
     * user uses the <tab> key. */
    linenoiseSetCompletionCallback(completion);
    linenoiseSetHintsCallback(hints);

    /* Load history from file. The history file is just a plain text file
     * where entries are separated by newlines. */
    linenoiseHistoryLoad("history.txt"); /* Load the history at startup */

    /* Now this is the main loop of the typical linenoise-based application.
     * The call to linenoise() will block as long as the user types something
     * and presses enter.
     *
     * The typed string is returned as a malloc() allocated string by
     * linenoise, so the user needs to free() it. */

    while (1)
    {
        if (!async)
        {
            line = linenoise("hello> ");
            if (line == NULL)
                break;
        }
        else
        {
            /* Asynchronous mode using the multiplexing API: wait for
             * data on stdin, and simulate async data coming from some source
             * using the select(2) timeout. */
            struct linenoiseState ls;
            char buf[1024];
            linenoiseEditStart(&ls, -1, -1, buf, sizeof(buf), "hello> ");
            while (1)
            {
                fd_set readfds;
                struct timeval tv;
                int retval;

                FD_ZERO(&readfds);
                FD_SET(ls.ifd, &readfds);
                tv.tv_sec = 1; // 1 sec timeout
                tv.tv_usec = 0;

                retval = select(ls.ifd + 1, &readfds, NULL, NULL, &tv);
                if (retval == -1)
                {
                    perror("select()");
                    exit(1);
                }
                else if (retval)
                {
                    line = linenoiseEditFeed(&ls);
                    /* A NULL return means: line editing is continuing.
                     * Otherwise the user hit enter or stopped editing
                     * (CTRL+C/D). */
                    if (line != linenoiseEditMore)
                        break;
                }
                else
                {
                    // Timeout occurred
                    static int counter = 0;
                    linenoiseHide(&ls);
                    printf("Async output %d.\n", counter++);
                    linenoiseShow(&ls);
                }
            }
            linenoiseEditStop(&ls);
            if (line == NULL)
                exit(0); /* Ctrl+D/C. */
        }

        /* Do something with the string. */
        if (line[0] == 'q')
        {
            printf("exit\n");
            break;
        }
        else if (line[0] != '\0' && line[0] != '/')
        {
            printf("echo: '%s'\n", line);
            linenoiseHistoryAdd(line);           /* Add to the history. */
            linenoiseHistorySave("history.txt"); /* Save the history on disk. */
        }
        else if (!strncmp(line, "/historylen", 11))
        {
            /* The "/historylen" command will change the history len. */
            int len = atoi(line + 11);
            linenoiseHistorySetMaxLen(len);
        }
        else if (!strncmp(line, "/mask", 5))
        {
            linenoiseMaskModeEnable();
        }
        else if (!strncmp(line, "/unmask", 7))
        {
            linenoiseMaskModeDisable();
        }
        else if (line[0] == '/')
        {
            printf("Unreconized command: %s\n", line);
        }
        free(line);
    }
    return 0;
}