/***********************************************************
Copyright 1991, 1992, 1993 by Stichting Mathematisch Centrum,
Amsterdam, The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the names of Stichting Mathematisch
Centrum or CWI not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior permission.

STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* Module definition and import implementation */

#include "allobjects.h"

#include "node.h"
#include "token.h"
#include "graminit.h"
#include "import.h"
#include "errcode.h"
#include "sysmodule.h"
#include "pythonrun.h"
#include "marshal.h"
#include "compile.h"
#include "eval.h"
#include "osdefs.h"

extern int verbose; /* Defined in pythonmain.c */

extern long getmtime(); /* Defined in posixmodule.c */

#ifdef DEBUG
#define D(x) x
#else
#define D(x)
#endif

#ifdef USE_DL
#ifdef SUN_SHLIB
#include <dlfcn.h>
typedef void (*dl_funcptr)();
#else
#include "dl.h"
#endif /* SUN_SHLIB */

extern char *argv0;
#endif

/* Magic word to reject .pyc files generated by other Python versions */

#define MAGIC 0x999902L /* Increment by one for each incompatible change */

static object *modules;

/* Forward */
static int init_builtin PROTO((char *));

/* Initialization */

void
initimport()
{
	if ((modules = newdictobject()) == NULL)
		fatal("no mem for dictionary of modules");
}

object *
get_modules()
{
	return modules;
}

object *
add_module(name)
	char *name;
{
	object *m;
	if ((m = dictlookup(modules, name)) != NULL && is_moduleobject(m))
		return m;
	m = newmoduleobject(name);
	if (m == NULL)
		return NULL;
	if (dictinsert(modules, name, m) != 0) {
		DECREF(m);
		return NULL;
	}
	DECREF(m); /* Yes, it still exists, in modules! */
	return m;
}

enum filetype {SEARCH_ERROR, PY_SOURCE, PY_COMPILED, C_EXTENSION};

static struct filedescr {
	char *suffix;
	char *mode;
	enum filetype type;
} filetab[] = {
#ifdef USE_DL
#ifdef SUN_SHLIB
	{"module.so", "rb", C_EXTENSION},
#else
	{"module.o", "rb", C_EXTENSION},
#endif /* SUN_SHLIB */
#endif /* USE_DL */
	{".py", "r", PY_SOURCE},
	{".pyc", "rb", PY_COMPILED},
	{0, 0}
};

static object *
get_module(m, name, m_ret)
	/*module*/object *m;
	char *name;
	object **m_ret;
{
	int err, npath, i, len;
	long magic;
	long mtime, pyc_mtime;
	char namebuf[MAXPATHLEN+1];
	struct filedescr *fdp;
	FILE *fp = NULL, *fpc = NULL;
	node *n = NULL;
	object *path, *v, *d;
	codeobject *co = NULL;

	path = sysget("path");
	if (path == NULL || !is_listobject(path)) {
		err_setstr(ImportError,
			   "sys.path must be list of directory names");
		return NULL;
	}
	npath = getlistsize(path);
	for (i = 0; i < npath; i++) {
		v = getlistitem(path, i);
		if (!is_stringobject(v))
			continue;
		strcpy(namebuf, getstringvalue(v));
		len = getstringsize(v);
		if (len > 0 && namebuf[len-1] != SEP)
			namebuf[len++] = SEP;
		strcpy(namebuf+len, name);
		len += strlen(name);
		for (fdp = filetab; fdp->suffix != NULL; fdp++) {
			strcpy(namebuf+len, fdp->suffix);
			if (verbose > 1)
				fprintf(stderr, "# trying %s\n", namebuf);
			fp = fopen(namebuf, fdp->mode);
			if (fp != NULL)
				break;
		}
		if (fp != NULL)
			break;
	}
	if (fp == NULL) {
		sprintf(namebuf, "No module named %s", name);
		err_setstr(ImportError, namebuf);
		return NULL;
	}

	switch (fdp->type) {

	case PY_SOURCE:
		mtime = getmtime(namebuf);
		len = strlen(namebuf);
		strcpy(namebuf + len, "c");
		fpc = fopen(namebuf, "rb");
		if (fpc != NULL) {
			magic = rd_long(fpc);
			if (magic != MAGIC) {
				if (verbose)
					fprintf(stderr,
						"# %s.pyc has bad magic\n",
						name);
			}
			else {
				pyc_mtime = rd_long(fpc);
				if (pyc_mtime != mtime) {
					if (verbose)
						fprintf(stderr,
						  "# %s.pyc has bad mtime\n",
						  name);
				}
				else {
					fclose(fp);
					fp = fpc;
					if (verbose)
					   fprintf(stderr,
					     "# %s.pyc matches %s.py\n",
						   name, name);
					goto use_compiled;
				}
			}
			fclose(fpc);
		}
		namebuf[len] = '\0';
		err = parse_file(fp, namebuf, file_input, &n);
		if (err != E_DONE) {
			err_input(err);
			return NULL;
		}
		co = compile(n, namebuf);
		freetree(n);
		if (co == NULL)
			return NULL;
		if (verbose)
			fprintf(stderr,
				"import %s # from %s\n", name, namebuf);
		/* Now write the code object to the ".pyc" file */
		strcpy(namebuf + len, "c");
		fpc = fopen(namebuf, "wb");
		if (fpc == NULL) {
			if (verbose)
				fprintf(stderr,
					"# can't create %s\n", namebuf);
		}
		else {
			wr_long(MAGIC, fpc);
			/* First write a 0 for mtime */
			wr_long(0L, fpc);
			wr_object((object *)co, fpc);
			if (ferror(fpc)) {
				if (verbose)
					fprintf(stderr,
						"# can't write %s\n", namebuf);
				/* Don't keep partial file */
				fclose(fpc);
				(void) unlink(namebuf);
			}
			else {
				/* Now write the true mtime */
				fseek(fpc, 4L, 0);
				wr_long(mtime, fpc);
				fflush(fpc);
				fclose(fpc);
				if (verbose)
					fprintf(stderr,
						"# wrote %s\n", namebuf);
			}
		}
		break;

	case PY_COMPILED:
		if (verbose)
			fprintf(stderr, "# %s.pyc without %s.py\n",
				name, name);
		magic = rd_long(fp);
		if (magic != MAGIC) {
			err_setstr(ImportError,
				   "Bad magic number in .pyc file");
			return NULL;
		}
		(void) rd_long(fp);
	use_compiled:
		v = rd_object(fp);
		fclose(fp);
		if (v == NULL || !is_codeobject(v)) {
			XDECREF(v);
			err_setstr(ImportError,
				   "Bad code object in .pyc file");
			return NULL;
		}
		co = (codeobject *)v;
		if (verbose)
			fprintf(stderr,
				"import %s # precompiled from %s\n",
				name, namebuf);
		break;

#ifdef USE_DL
	case C_EXTENSION:
	      {
		char funcname[258];
		dl_funcptr p;
		fclose(fp);
		sprintf(funcname, "init%s", name);
#ifdef SUN_SHLIB
		{
		  void *handle = dlopen (namebuf, 1);
		  p = (dl_funcptr) dlsym(handle, funcname);
		}
#else
		p =  dl_loadmod(argv0, namebuf, funcname);
#endif /* SUN_SHLIB */
		if (p == NULL) {
			err_setstr(ImportError,
			   "dynamic module does not define init function");
			return NULL;
		} else {
			(*p)();
			*m_ret = m = dictlookup(modules, name);
			if (m == NULL) {
				err_setstr(SystemError,
				   "dynamic module not initialized properly");
				return NULL;
			} else {
				if (verbose)
					fprintf(stderr,
				"import %s # dynamically loaded from %s\n",
						name, namebuf);
				INCREF(None);
				return None;
			}
		}
		break;
	      }
#endif /* USE_DL */

	default:
		fclose(fp);
		err_setstr(SystemError,
			   "search loop returned unexpected result");
		return NULL;

	}

	/* We get here for either PY_SOURCE or PY_COMPILED */
	if (m == NULL) {
		m = add_module(name);
		if (m == NULL) {
			freetree(n);
			return NULL;
		}
		*m_ret = m;
	}
	d = getmoduledict(m);
	v = eval_code(co, d, d, d, (object *)NULL);
	DECREF(co);
	return v;
}

static object *
load_module(name)
	char *name;
{
	object *m, *v;
	v = get_module((object *)NULL, name, &m);
	if (v == NULL)
		return NULL;
	DECREF(v);
	return m;
}

object *
import_module(name)
	char *name;
{
	object *m;
	int n;
	if ((m = dictlookup(modules, name)) == NULL) {
		if ((n = init_builtin(name)) || (n = init_frozen(name))) {
			if (n < 0)
				return NULL;
			if ((m = dictlookup(modules, name)) == NULL)
				err_setstr(SystemError,
					   "builtin module missing");
		}
		else {
			m = load_module(name);
		}
	}
	return m;
}

object *
reload_module(m)
	object *m;
{
	char *name;
	if (m == NULL || !is_moduleobject(m)) {
		err_setstr(TypeError, "reload() argument must be module");
		return NULL;
	}
	name = getmodulename(m);
	if (name == NULL)
		return NULL;
	/* XXX Ought to check for builtin modules -- can't reload these... */
	return get_module(m, name, (object **)NULL);
}

void
doneimport()
{
	if (modules != NULL) {
		int pos;
		object *modname, *module;
		/* Explicitly erase all modules; this is the safest way
		   to get rid of at least *some* circular dependencies */
		pos = 0;
		while (mappinggetnext(modules, &pos, &modname, &module)) {
			if (is_moduleobject(module)) {
				object *dict;
				dict = getmoduledict(module);
				if (dict != NULL && is_dictobject(dict))
					mappingclear(dict);
			}
		}
		mappingclear(modules);
	}
	DECREF(modules);
	modules = NULL;
}


/* Initialize built-in modules when first imported */

static int
init_builtin(name)
	char *name;
{
	int i;
	for (i = 0; inittab[i].name != NULL; i++) {
		if (strcmp(name, inittab[i].name) == 0) {
			if (verbose)
				fprintf(stderr, "import %s # builtin\n",
					name);
			(*inittab[i].initfunc)();
			return 1;
		}
	}
	return 0;
}

extern struct frozen {
	char *name;
	char *code;
	int size;
} frozen_modules[];

int
init_frozen(name)
	char *name;
{
	struct frozen *p;
	codeobject *co;
	object *m, *d, *v;
	for (p = frozen_modules; ; p++) {
		if (p->name == NULL)
			return 0;
		if (strcmp(p->name, name) == 0)
			break;
	}
	if (verbose)
		fprintf(stderr, "import %s # frozen\n", name);
	co = (codeobject *) rds_object(p->code, p->size);
	if (co == NULL)
		return -1;
	if ((m = add_module(name)) == NULL ||
	    (d = getmoduledict(m)) == NULL ||
	    (v = eval_code(co, d, d, d, (object*)NULL)) == NULL) {
		DECREF(co);
		return -1;
	}
	DECREF(co);
	DECREF(v);
	return 1;
}