cpython/Python/sysmodule.c

/* System module */

/*
Various bits of information used by the interpreter are collected in
module 'sys'.
Function member:
- exit(sts): call (C, POSIX) exit(sts)
Data members:
- stdin, stdout, stderr: standard file objects
- modules: the table of modules (dictionary)
- path: module search path (list of strings)
- argv: script arguments (list of strings)
- ps1, ps2: optional primary and secondary prompts (strings)
*/

#include "allobjects.h"

#include "sysmodule.h"
#include "import.h"
#include "modsupport.h"

/* Define delimiter used in $PYTHONPATH */

#ifdef THINK_C
#define DELIM ' '
#endif

#ifndef DELIM
#define DELIM ':'
#endif

static object *sysdict;

object *
sysget(name)
	char *name;
{
	return dictlookup(sysdict, name);
}

FILE *
sysgetfile(name, def)
	char *name;
	FILE *def;
{
	FILE *fp = NULL;
	object *v = sysget(name);
	if (v != NULL)
		fp = getfilefile(v);
	if (fp == NULL)
		fp = def;
	return fp;
}

int
sysset(name, v)
	char *name;
	object *v;
{
	if (v == NULL)
		return dictremove(sysdict, name);
	else
		return dictinsert(sysdict, name, v);
}

static object *
sys_exit(self, args)
	object *self;
	object *args;
{
	int sts;
	if (!getintarg(args, &sts))
		return NULL;
	goaway(sts);
	exit(sts); /* Just in case */
	/* NOTREACHED */
}

static struct methodlist sys_methods[] = {
	{"exit",	sys_exit},
	{NULL,		NULL}		/* sentinel */
};

static object *sysin, *sysout, *syserr;

void
initsys()
{
	object *m = initmodule("sys", sys_methods);
	sysdict = getmoduledict(m);
	INCREF(sysdict);
	/* NB keep an extra ref to the std files to avoid closing them
	   when the user deletes them */
	/* XXX File objects should have a "don't close" flag instead */
	sysin = newopenfileobject(stdin, "<stdin>", "r");
	sysout = newopenfileobject(stdout, "<stdout>", "w");
	syserr = newopenfileobject(stderr, "<stderr>", "w");
	if (err_occurred())
		fatal("can't create sys.std* file objects");
	dictinsert(sysdict, "stdin", sysin);
	dictinsert(sysdict, "stdout", sysout);
	dictinsert(sysdict, "stderr", syserr);
	dictinsert(sysdict, "modules", get_modules());
	if (err_occurred())
		fatal("can't insert sys.* objects in sys dict");
}

static object *
makepathobject(path, delim)
	char *path;
	int delim;
{
	int i, n;
	char *p;
	object *v, *w;
	
	n = 1;
	p = path;
	while ((p = strchr(p, delim)) != NULL) {
		n++;
		p++;
	}
	v = newlistobject(n);
	if (v == NULL)
		return NULL;
	for (i = 0; ; i++) {
		p = strchr(path, delim);
		if (p == NULL)
			p = strchr(path, '\0'); /* End of string */
		w = newsizedstringobject(path, (int) (p - path));
		if (w == NULL) {
			DECREF(v);
			return NULL;
		}
		setlistitem(v, i, w);
		if (*p == '\0')
			break;
		path = p+1;
	}
	return v;
}

void
setpythonpath(path)
	char *path;
{
	object *v;
	if ((v = makepathobject(path, DELIM)) == NULL)
		fatal("can't create sys.path");
	if (sysset("path", v) != 0)
		fatal("can't assign sys.path");
	DECREF(v);
}

static object *
makeargvobject(argc, argv)
	int argc;
	char **argv;
{
	object *av;
	if (argc < 0 || argv == NULL)
		argc = 0;
	av = newlistobject(argc);
	if (av != NULL) {
		int i;
		for (i = 0; i < argc; i++) {
			object *v = newstringobject(argv[i]);
			if (v == NULL) {
				DECREF(av);
				av = NULL;
				break;
			}
			setlistitem(av, i, v);
		}
	}
	return av;
}

void
setpythonargv(argc, argv)
	int argc;
	char **argv;
{
	object *av = makeargvobject(argc, argv);
	if (av == NULL)
		fatal("no mem for sys.argv");
	if (sysset("argv", av) != 0)
		fatal("can't assign sys.argv");
	DECREF(av);
}