command.c #1

/*
 *	C4 -- CVS like front end to the Perforce p4 SCM tool.
 *
 * Copyright (c) 1997, Neil Russell.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Neil Russell.
 * 4. The name Neil Russell may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY NEIL RUSSELL ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL NEIL RUSSELL BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *	Command execution.
 */

#include	"defs.h"

/**************************************************/
/*
 *	Command invocation.
 */

int		CmdArgs;		/* Number of args seen */
int		CmdExec = 1;		/* '-n' ommand line option */
char *		CmdP4 = "p4";		/* Name of the real p4 command */

static char *	cmd;			/* Command string under construction */
static int	cmd_index;		/* Next available argument */
static int	cmd_base;		/* First argument of xargs list */
static int	cmd_size;		/* Available argument space */
static int	cmd_clobber;		/* Command changes things */
static void	(*cmd_func)(char *);	/* Output processing function */


void
Command(char * c, void (*f)(char *), int clobber)
{
	/*
	 *	Calculate the size of the argument space.
	 */
	if (!cmd)
	{
		char **		ep;
		extern char **	environ;

		cmd_size = NCARGS - 4 * 1024;
		for (ep = environ; *ep; ep++)
			cmd_size -= strlen(*ep) + 1 + sizeof (*ep);
		if (cmd_size > 32768)
			cmd_size = 32768;
		cmd = Alloc(cmd_size);
	}

	/*
	 *	Copy the initial command string into the arg string (we
	 *	assume that the command string will fit in the available
	 *	argument space).
	 */
	strcpy(cmd, CmdP4);
	strcat(cmd, " ");
	strcat(cmd, c);
	cmd_index = strlen(cmd);
	cmd_base = cmd_index;
	cmd_func = f;
	cmd_clobber = clobber;
	CmdArgs = 0;
}


void
CommandDone(void)
{
	FILE *		fd;
	char		line[1024];

	if (Debug >= 1)
		printf("\t%s\n", cmd);

	if (cmd_clobber && !CmdExec)
		return;

	if (!cmd_func)
		system(cmd);
	else
	{
		fd = popen(cmd, "r");
		if (!fd)
		{
			cmd[cmd_base] = '\0';
			Error(1, "Can't popen command (%.40s)", cmd);
		}

		while (fgets(line, sizeof line, fd))
		{
			char *		nl;

			if (nl = strchr(line, '\n'))
				*nl = '\0';
			(*cmd_func)(line);
		}

		pclose(fd);
	}
}


void
CommandArg(char * a)
{
	int		l;

	l = strlen(a);
	if (cmd_index + 1 + l + 1 > cmd_size)
	{
		CommandDone();
		cmd_index = cmd_base;
	}

	strcpy(&cmd[cmd_index++], " ");
	strcpy(&cmd[cmd_index], a);
	cmd_index += l;
	CmdArgs++;
}