prompt.c

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/*
 * psql - the PostgreSQL interactive terminal
 *
 * Copyright (c) 2000-2013, PostgreSQL Global Development Group
 *
 * src/bin/psql/prompt.c
 */
#include "postgres_fe.h"

#ifdef WIN32
#include <io.h>
#include <win32.h>
#endif

#ifdef HAVE_UNIX_SOCKETS
#include <unistd.h>
#include <netdb.h>
#endif

#include "common.h"
#include "input.h"
#include "prompt.h"
#include "settings.h"


/*--------------------------
 * get_prompt
 *
 * Returns a statically allocated prompt made by interpolating certain
 * tcsh style escape sequences into pset.vars "PROMPT1|2|3".
 * (might not be completely multibyte safe)
 *
 * Defined interpolations are:
 * %M - database server "hostname.domainname", "[local]" for AF_UNIX
 *      sockets, "[local:/dir/name]" if not default
 * %m - like %M, but hostname only (before first dot), or always "[local]"
 * %> - database server port number
 * %n - database user name
 * %/ - current database
 * %~ - like %/ but "~" when database name equals user name
 * %# - "#" if superuser, ">" otherwise
 * %R - in prompt1 normally =, or ^ if single line mode,
 *          or a ! if session is not connected to a database;
 *      in prompt2 -, *, ', or ";
 *      in prompt3 nothing
 * %x - transaction status: empty, *, !, ? (unknown or no connection)
 * %? - the error code of the last query (not yet implemented)
 * %% - a percent sign
 *
 * %[0-9]          - the character with the given decimal code
 * %0[0-7]         - the character with the given octal code
 * %0x[0-9A-Fa-f]  - the character with the given hexadecimal code
 *
 * %`command`      - The result of executing command in /bin/sh with trailing
 *                   newline stripped.
 * %:name:         - The value of the psql variable 'name'
 * (those will not be rescanned for more escape sequences!)
 *
 * %[ ... %]       - tell readline that the contained text is invisible
 *
 * If the application-wide prompts become NULL somehow, the returned string
 * will be empty (not NULL!).
 *--------------------------
 */

char *
get_prompt(promptStatus_t status)
{
#define MAX_PROMPT_SIZE 256
    static char destination[MAX_PROMPT_SIZE + 1];
    char        buf[MAX_PROMPT_SIZE + 1];
    bool        esc = false;
    const char *p;
    const char *prompt_string = "? ";

    switch (status)
    {
        case PROMPT_READY:
            prompt_string = pset.prompt1;
            break;

        case PROMPT_CONTINUE:
        case PROMPT_SINGLEQUOTE:
        case PROMPT_DOUBLEQUOTE:
        case PROMPT_DOLLARQUOTE:
        case PROMPT_COMMENT:
        case PROMPT_PAREN:
            prompt_string = pset.prompt2;
            break;

        case PROMPT_COPY:
            prompt_string = pset.prompt3;
            break;
    }

    destination[0] = '\0';

    for (p = prompt_string;
         *p && strlen(destination) < sizeof(destination) - 1;
         p++)
    {
        memset(buf, 0, sizeof(buf));
        if (esc)
        {
            switch (*p)
            {
                    /* Current database */
                case '/':
                    if (pset.db)
                        strlcpy(buf, PQdb(pset.db), sizeof(buf));
                    break;
                case '~':
                    if (pset.db)
                    {
                        const char *var;

                        if (strcmp(PQdb(pset.db), PQuser(pset.db)) == 0 ||
                            ((var = getenv("PGDATABASE")) && strcmp(var, PQdb(pset.db)) == 0))
                            strlcpy(buf, "~", sizeof(buf));
                        else
                            strlcpy(buf, PQdb(pset.db), sizeof(buf));
                    }
                    break;

                    /* DB server hostname (long/short) */
                case 'M':
                case 'm':
                    if (pset.db)
                    {
                        const char *host = PQhost(pset.db);

                        /* INET socket */
                        if (host && host[0] && !is_absolute_path(host))
                        {
                            strlcpy(buf, host, sizeof(buf));
                            if (*p == 'm')
                                buf[strcspn(buf, ".")] = '\0';
                        }
#ifdef HAVE_UNIX_SOCKETS
                        /* UNIX socket */
                        else
                        {
                            if (!host
                                || strcmp(host, DEFAULT_PGSOCKET_DIR) == 0
                                || *p == 'm')
                                strlcpy(buf, "[local]", sizeof(buf));
                            else
                                snprintf(buf, sizeof(buf), "[local:%s]", host);
                        }
#endif
                    }
                    break;
                    /* DB server port number */
                case '>':
                    if (pset.db && PQport(pset.db))
                        strlcpy(buf, PQport(pset.db), sizeof(buf));
                    break;
                    /* DB server user name */
                case 'n':
                    if (pset.db)
                        strlcpy(buf, session_username(), sizeof(buf));
                    break;

                case '0':
                case '1':
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7':
                    *buf = (char) strtol(p, (char **) &p, 8);
                    --p;
                    break;
                case 'R':
                    switch (status)
                    {
                        case PROMPT_READY:
                            if (!pset.db)
                                buf[0] = '!';
                            else if (!pset.singleline)
                                buf[0] = '=';
                            else
                                buf[0] = '^';
                            break;
                        case PROMPT_CONTINUE:
                            buf[0] = '-';
                            break;
                        case PROMPT_SINGLEQUOTE:
                            buf[0] = '\'';
                            break;
                        case PROMPT_DOUBLEQUOTE:
                            buf[0] = '"';
                            break;
                        case PROMPT_DOLLARQUOTE:
                            buf[0] = '$';
                            break;
                        case PROMPT_COMMENT:
                            buf[0] = '*';
                            break;
                        case PROMPT_PAREN:
                            buf[0] = '(';
                            break;
                        default:
                            buf[0] = '\0';
                            break;
                    }
                    break;

                case 'x':
                    if (!pset.db)
                        buf[0] = '?';
                    else
                        switch (PQtransactionStatus(pset.db))
                        {
                            case PQTRANS_IDLE:
                                buf[0] = '\0';
                                break;
                            case PQTRANS_ACTIVE:
                            case PQTRANS_INTRANS:
                                buf[0] = '*';
                                break;
                            case PQTRANS_INERROR:
                                buf[0] = '!';
                                break;
                            default:
                                buf[0] = '?';
                                break;
                        }
                    break;

                case '?':
                    /* not here yet */
                    break;

                case '#':
                    if (is_superuser())
                        buf[0] = '#';
                    else
                        buf[0] = '>';
                    break;

                    /* execute command */
                case '`':
                    {
                        FILE       *fd;
                        char       *file = pg_strdup(p + 1);
                        int         cmdend;

                        cmdend = strcspn(file, "`");
                        file[cmdend] = '\0';
                        fd = popen(file, "r");
                        if (fd)
                        {
                            if (fgets(buf, sizeof(buf), fd) == NULL)
                                buf[0] = '\0';
                            pclose(fd);
                        }
                        if (strlen(buf) > 0 && buf[strlen(buf) - 1] == '\n')
                            buf[strlen(buf) - 1] = '\0';
                        free(file);
                        p += cmdend + 1;
                        break;
                    }

                    /* interpolate variable */
                case ':':
                    {
                        char       *name;
                        const char *val;
                        int         nameend;

                        name = pg_strdup(p + 1);
                        nameend = strcspn(name, ":");
                        name[nameend] = '\0';
                        val = GetVariable(pset.vars, name);
                        if (val)
                            strlcpy(buf, val, sizeof(buf));
                        free(name);
                        p += nameend + 1;
                        break;
                    }

                case '[':
                case ']':
#if defined(USE_READLINE) && defined(RL_PROMPT_START_IGNORE)

                    /*
                     * readline >=4.0 undocumented feature: non-printing
                     * characters in prompt strings must be marked as such, in
                     * order to properly display the line during editing.
                     */
                    buf[0] = (*p == '[') ? RL_PROMPT_START_IGNORE : RL_PROMPT_END_IGNORE;
                    buf[1] = '\0';
#endif   /* USE_READLINE */
                    break;

                default:
                    buf[0] = *p;
                    buf[1] = '\0';
                    break;

            }
            esc = false;
        }
        else if (*p == '%')
            esc = true;
        else
        {
            buf[0] = *p;
            buf[1] = '\0';
            esc = false;
        }

        if (!esc)
            strlcat(destination, buf, sizeof(destination));
    }

    return destination;
}