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

/*  slibtool: a skinny libtool implementation, written in C        */

/*  Copyright (C) 2016  Z. Gilboa                                  */

/*  Released under the Standard MIT License; see COPYING.SLIBTOOL. */

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

#include <stdint.h>

#include <unistd.h>

#include <stdlib.h>

#include <string.h>

#include <slibtool/slibtool.h>

#define SLBT_ARGV_SPARE_PTRS	16

struct slbt_exec_ctx_impl {

	int			argc;

	char *			args;

	struct slbt_exec_ctx	ctx;

	char *			buffer[];

};

static size_t slbt_parse_comma_separated_flags(

	const char *	str,

	int *		argc)

{

	const char * ch;

	for (ch=str; *ch; ch++)

		if (*ch == ',')

			(*argc)++;

	return ch - str;

}

static char * slbt_source_file(char ** argv)

{

	char **	parg;

	char *	ch;

	for (parg=argv; *parg; parg++)

		if ((ch = strrchr(*parg,'.')))

			if ((!(strcmp(++ch,"s")))

					|| (!(strcmp(ch,"S")))

					|| (!(strcmp(ch,"c")))

					|| (!(strcmp(ch,"cc")))

					|| (!(strcmp(ch,"cxx"))))

				return *parg;

	return 0;

}

static struct slbt_exec_ctx_impl * slbt_exec_ctx_alloc(

	const struct slbt_driver_ctx *	dctx)

{

	struct slbt_exec_ctx_impl *	ictx;

	size_t				size;

	int				argc;

	char *				args;

	char *				csrc;

	char **				parg;

	argc = 0;

	csrc = 0;

	/* clerical buffer size (guard, suffix, version) */

	size  = strlen(".lo") + strlen(".libs/") + 2*sizeof('\0');

	size += 36*strlen(".0000") + 36*sizeof('\0');

	/* buffer size (cargv, -Wc) */

	for (parg=dctx->cctx->cargv; *parg; parg++, argc++)

		if (!(strncmp("-Wc,",*parg,4)))

			size += sizeof('\0') + slbt_parse_comma_separated_flags(

					parg[4],&argc);

		else

			size += sizeof('\0') + strlen(*parg);

	/* buffer size (ldirname, lbasename, lobjname) */

	if (dctx->cctx->output)

		size += 3*strlen(dctx->cctx->output);

	else if ((csrc = slbt_source_file(dctx->cctx->cargv)))

		size += 3*strlen(csrc);

	/* alloc */

	if (!(args = malloc(size)))

		return 0;

	size = sizeof(*ictx) + (argc+SLBT_ARGV_SPARE_PTRS)*sizeof(char *);

	if (!(ictx = calloc(1,size))) {

		free(args);

		return 0;

	}

	ictx->args = args;

	ictx->argc = argc;

	ictx->ctx.csrc = csrc;

	return ictx;

}

int  slbt_get_exec_ctx(

	const struct slbt_driver_ctx *	dctx,

	struct slbt_exec_ctx **		ectx)

{

	struct slbt_exec_ctx_impl *	ictx;

	char **				parg;

	char *				ch;

	char *				slash;

	const char *			ref;

	int				i;

	/* alloc */

	if (!(ictx = slbt_exec_ctx_alloc(dctx)))

		return -1;

	/* init with guard for later .lo check */

	ch                = ictx->args + strlen(".lo");

	ictx->ctx.argv    = ictx->buffer;

	/* <compiler> */

	ictx->ctx.program = dctx->cctx->cargv[0];

	/* ldirname, lbasename */

	ref = (dctx->cctx->output)

		? dctx->cctx->output

		: ictx->ctx.csrc;

	if (ref && !ictx->ctx.csrc && (slash = strrchr(ref,'/'))) {

		ictx->ctx.ldirname = ch;

		strcpy(ch,ref);

		ch += slash - ref;

		ch += sprintf(ch,"%s","/.libs/");

		ch++;

		ictx->ctx.lbasename = ch;

		ch += sprintf(ch,"%s",++slash);

		ch++;

	} else if (ref) {

		ictx->ctx.ldirname = ch;

		ch += sprintf(ch,"%s",".libs/");

		ch++;

		ictx->ctx.lbasename = ch;

		slash = strrchr(ref,'/');

		ch += sprintf(ch,"%s",slash ? ++slash : ref);

		ch++;

	}

	/* lbasename suffix */

	if (ref && (dctx->cctx->mode == SLBT_MODE_COMPILE)) {

		if ((ch[-4] == '.') && (ch[-3] == 'l') && (ch[-2] == 'o')) {

			ch[-3] = 'o';

			ch[-2] = '\0';

			ch--;

		} else if (ictx->ctx.csrc) {

			if ((ch = strrchr(ictx->ctx.lbasename,'.'))) {

				*++ch = 'o';

				*++ch = '\0';

				ch++;

			}

		}

	}

	/* cargv, -Wc */

	for (i=0, parg=dctx->cctx->cargv; *parg; parg++, ch++) {

		if (!(strncmp("-Wc,",*parg,4))) {

			strcpy(ch,parg[4]);

			ictx->ctx.argv[i++] = ch;

			for (; *ch; ch++)

				if (*ch == ',') {

					*ch = '\0';

					ictx->ctx.argv[i++] = ch+1;

				}

		} else {

			ictx->ctx.argv[i++] = ch;

			ch += sprintf(ch,"%s",*parg);

		}

	}

	if (dctx->cctx->mode == SLBT_MODE_COMPILE) {

		if (dctx->cctx->drvflags & SLBT_DRIVER_SHARED) {

			ictx->ctx.argv[i++] = "-DPIC";

			ictx->ctx.argv[i++] = "-fPIC";

		}

		ictx->ctx.argv[i++] = "-c";

	}

	/* output file name */

	if (ref) {

		ictx->ctx.argv[i++] = "-o";

		ictx->ctx.argv[i++] = ch;

		ictx->ctx.lobjname  = ch;

		sprintf(ch,"%s%s",

			ictx->ctx.ldirname,

			ictx->ctx.lbasename);

	}

	*ectx = &ictx->ctx;

	return 0;

}

static int slbt_free_exec_ctx_impl(

	struct slbt_exec_ctx_impl *	ictx,

	int				status)

{

	free(ictx->args);

	free (ictx);

	return status;

}

void slbt_free_exec_ctx(struct slbt_exec_ctx * ctx)

{

	struct slbt_exec_ctx_impl *	ictx;

	uintptr_t			addr;

	if (ctx) {

		addr = (uintptr_t)ctx - offsetof(struct slbt_exec_ctx_impl,ctx);

		ictx = (struct slbt_exec_ctx_impl *)addr;

		slbt_free_exec_ctx_impl(ictx,0);

	}

}