parser.c

来自「lustre 1.6.5 source code」· C语言 代码 · 共 643 行 · 第 1/2 页

/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 * Copyright (C) 2001 Cluster File Systems, Inc.
 *
 *   This file is part of Lustre, http://www.sf.net/projects/lustre/
 *
 *   Lustre is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Lustre is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Lustre; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stddef.h>
#include <unistd.h>
#include <sys/param.h>
#include <assert.h>
#include <lnet/api-support.h>

#include "parser.h"

static command_t * top_level;      /* Top level of commands, initialized by
                                    * InitParser                            */
static char * parser_prompt = NULL;/* Parser prompt, set by InitParser      */
static int done;		   /* Set to 1 if user types exit or quit   */


/* static functions */
static char *skipwhitespace(char *s);
static char *skiptowhitespace(char *s);
static command_t *find_cmd(char *name, command_t cmds[], char **next);
static int process(char *s, char **next, command_t *lookup, command_t **result,
                   char **prev);
static void print_commands(char *str, command_t *table);

static char * skipwhitespace(char * s)
{
    char * t;
    int    len;

    len = (int)strlen(s);
    for (t = s; t <= s + len && isspace(*t); t++);
    return(t);
}


static char * skiptowhitespace(char * s)
{
    char * t;

    for (t = s; *t && !isspace(*t); t++);
    return(t);
}

static int line2args(char *line, char **argv, int maxargs)
{
    char *arg;
    int i = 0;

    arg = strtok(line, " \t");
    if ( arg ) {
            argv[i] = arg;
	i++;
    } else
	return 0;

    while( (arg = strtok(NULL, " \t")) && (i <= maxargs)) {
	argv[i] = arg;
	i++;
    }
    return i;
}

/* find a command -- return it if unique otherwise print alternatives */
static command_t *Parser_findargcmd(char *name, command_t cmds[])
{
	command_t *cmd;

	for (cmd = cmds; cmd->pc_name; cmd++) {
		if (strcmp(name, cmd->pc_name) == 0)
			return cmd;
	}
	return NULL;
}

int Parser_execarg(int argc, char **argv, command_t cmds[])
{
	command_t *cmd;

        cmd = Parser_findargcmd(argv[0], cmds);
	if ( cmd ) {
                int rc = (cmd->pc_func)(argc, argv);
                if (rc == CMD_HELP)
                        fprintf(stderr, "%s\n", cmd->pc_help);
                return rc;
	} else {
		printf("Try interactive use without arguments or use one of:\n");
		for (cmd = cmds; cmd->pc_name; cmd++)
			printf("\"%s\" ", cmd->pc_name);
		printf("\nas argument.\n");
	}
	return -1;
}

/* returns the command_t * (NULL if not found) corresponding to a
   _partial_ match with the first token in name.  It sets *next to
   point to the following token. Does not modify *name. */
static command_t * find_cmd(char * name, command_t cmds[], char ** next)
{
        int    i, len;
    
        if (!cmds || !name ) 
                return NULL;
    
        /* This sets name to point to the first non-white space character,
           and next to the first whitespace after name, len to the length: do
           this with strtok*/
        name = skipwhitespace(name);
        *next = skiptowhitespace(name);
        len = *next - name;
        if (len == 0) 
                return NULL;

        for (i = 0; cmds[i].pc_name; i++) {
                if (strncasecmp(name, cmds[i].pc_name, len) == 0) {
                        *next = skipwhitespace(*next);
                        return(&cmds[i]);
                }
        }
        return NULL;
}

/* Recursively process a command line string s and find the command
   corresponding to it. This can be ambiguous, full, incomplete,
   non-existent. */
static int process(char *s, char ** next, command_t *lookup,
		   command_t **result, char **prev)
{
    *result = find_cmd(s, lookup, next);
    *prev = s;

        /* non existent */
        if ( ! *result ) 
                return CMD_NONE;

        /* found entry: is it ambigous, i.e. not exact command name and
           more than one command in the list matches.  Note that find_cmd
           points to the first ambiguous entry */
        if ( strncasecmp(s, (*result)->pc_name, strlen((*result)->pc_name)) &&
             find_cmd(s, (*result) + 1, next)) 
                return CMD_AMBIG;

        /* found a unique command: component or full? */
        if ( (*result)->pc_func ) {
                return CMD_COMPLETE;
        } else {
                if ( *next == '\0' ) {
                        return CMD_INCOMPLETE;
                } else {
                        return process(*next, next, (*result)->pc_sub_cmd, result, prev);
                }
        }
}

#ifdef HAVE_LIBREADLINE
static command_t * match_tbl;   /* Command completion against this table */
static char * command_generator(const char * text, int state)
{
        static int index,
                len;
        char       *name;

        /* Do we have a match table? */
        if (!match_tbl)
                return NULL;

        /* If this is the first time called on this word, state is 0 */
        if (!state) {
                index = 0;
                len = (int)strlen(text);
        }

        /* Return next name in the command list that paritally matches test */
        while ( (name = (match_tbl + index)->pc_name) ) {
                index++;

                if (strncasecmp(name, text, len) == 0) {
                        return(strdup(name));
                }
        }

    /* No more matches */
    return NULL;
}

/* probably called by readline */
static char **command_completion(char * text, int start, int end)
{
    command_t	* table;
    char	* pos;

    match_tbl = top_level;
    
    for (table = find_cmd(rl_line_buffer, match_tbl, &pos);
	 table; table = find_cmd(pos, match_tbl, &pos)) 
    {

	if (*(pos - 1) == ' ') match_tbl = table->pc_sub_cmd;
    }

    return completion_matches(text, command_generator);
}
#endif

/* take a string and execute the function or print help */
int execute_line(char * line)
{
        command_t         *cmd, *ambig;
        char *prev;
        char *next, *tmp;
        char *argv[MAXARGS];
        int         i;
        int rc = 0;

        switch( process(line, &next, top_level, &cmd, &prev) ) {
        case CMD_AMBIG:
                fprintf(stderr, "Ambiguous command \'%s\'\nOptions: ", line);
                while( (ambig = find_cmd(prev, cmd, &tmp)) ) {
                        fprintf(stderr, "%s ", ambig->pc_name);
                        cmd = ambig + 1;
                }
                fprintf(stderr, "\n");
                break;
        case CMD_NONE:
                fprintf(stderr, "No such command, type help\n");
                break;
        case CMD_INCOMPLETE:
                fprintf(stderr,
                        "'%s' incomplete command.  Use '%s x' where x is one of:\n",
                        line, line);
                fprintf(stderr, "\t");
                for (i = 0; cmd->pc_sub_cmd[i].pc_name; i++) {
                        fprintf(stderr, "%s ", cmd->pc_sub_cmd[i].pc_name);
                }
                fprintf(stderr, "\n");
                break;
        case CMD_COMPLETE:
                i = line2args(line, argv, MAXARGS);
                rc = (cmd->pc_func)(i, argv);

                if (rc == CMD_HELP)
                        fprintf(stderr, "%s\n", cmd->pc_help);

                break;
        }

        return rc;
}

int
noop_fn ()
{
        return (0);
}

/* just in case you're ever in an airplane and discover you 
   forgot to install readline-dev. :) */
int init_input() 
{
        int   interactive = isatty (fileno (stdin));

#ifdef HAVE_LIBREADLINE
        using_history();
        stifle_history(HISTORY);

        if (!interactive)
        {
                rl_prep_term_function = (rl_vintfunc_t *)noop_fn;
                rl_deprep_term_function = (rl_voidfunc_t *)noop_fn;
        }

        rl_attempted_completion_function = (CPPFunction *)command_completion;
        rl_completion_entry_function = (void *)command_generator;
#endif 
        return interactive;
}

#ifndef HAVE_LIBREADLINE
#define add_history(s)
char * readline(char * prompt) 
{
        char line[2048];
        int n = 0;
        if (prompt)
                printf ("%s", prompt);
        if (fgets(line, sizeof(line), stdin) == NULL)
                return (NULL);
        n = strlen(line);
        if (n && line[n-1] == '\n')
                line[n-1] = '\0';
        return strdup(line);
}
#endif

/* this is the command execution machine */
int Parser_commands(void)
{
        char *line, *s;
        int rc = 0;
        int interactive;