/*-
 * Copyright (c) 2006 Verdens Gang AS
 * Copyright (c) 2006-2011 Varnish Software AS
 * All rights reserved.
 *
 * Author: Poul-Henning Kamp <phk@phk.freebsd.dk>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
 */

#include "config.h"

#include <stdlib.h>
#include <string.h>

#include "vcc_compile.h"

#include "venc.h"
#include "vct.h"

/*--------------------------------------------------------------------*/

void
vcc_ErrToken(const struct vcc *tl, const struct token *t)
{

	if (t->tok == EOI)
		VSB_cat(tl->sb, "end of input");
	else if (t->tok == CSRC)
		VSB_cat(tl->sb, "C{ ... }C");
	else
		VSB_printf(tl->sb, "'%.*s'", PF(t));
}

void
vcc__ErrInternal(struct vcc *tl, const char *func, unsigned line)
{

	VSB_printf(tl->sb, "VCL compiler internal error at %s():%u\n",
	    func, line);
	tl->err = 1;
}

/*--------------------------------------------------------------------
 * Find start of source-line of token
 */

static void
vcc_iline(const struct token *t, const char **ll, int tail)
{
	const char *p, *b, *x;

	b = t->src->b;
	if (ll != NULL)
		*ll = b;
	x = tail ? t->e - 1 : t->b;
	for (p = b; p < x; p++) {
		if (*p == '\n') {
			if (ll != NULL)
				*ll = p + 1;
		}
	}
}

/*--------------------------------------------------------------------
 * Find and print src+line+pos of this token
 */

static void
vcc_icoord(struct vsb *vsb, const struct token *t, int tail)
{
	unsigned lin, pos;
	const char *p, *b, *x;

	lin = 1;
	pos = 0;
	b = t->src->b;
	x = tail ? t->e - 1 : t->b;
	for (p = b; p < x; p++) {
		if (*p == '\n') {
			lin++;
			pos = 0;
		} else if (*p == '\t') {
			pos &= ~7;
			pos += 8;
		} else
			pos++;
	}
	VSB_cat(vsb, "(");
	if (tail < 2)
		VSB_printf(vsb, "'%s' Line %u ", t->src->name, lin);
	VSB_printf(vsb, "Pos %u)", pos + 1);
}

/*--------------------------------------------------------------------*/

void
vcc_Coord(const struct vcc *tl, struct vsb *vsb, const struct token *t)
{

	if (t == NULL)
		t = tl->t;
	vcc_icoord(vsb, t, 0);
}

/*--------------------------------------------------------------------
 * Output one line of source code, starting at 'l' and ending at the
 * first NL or 'le'.
 */

static void
vcc_quoteline(const struct vcc *tl, const char *l, const char *le)
{
	const char *p;
	unsigned x, y;

	x = y = 0;
	for (p = l; p < le && *p != '\n'; p++) {
		if (*p == '\t') {
			y &= ~7;
			y += 8;
			while (x < y) {
				VSB_putc(tl->sb, ' ');
				x++;
			}
		} else {
			x++;
			y++;
			VSB_putc(tl->sb, *p);
		}
	}
	VSB_putc(tl->sb, '\n');
}

/*--------------------------------------------------------------------
 * Output a marker line for a sourceline starting at 'l' and ending at
 * the first NL or 'le'.  Characters between 'b' and 'e' are marked.
 */

static void
vcc_markline(const struct vcc *tl, const char *l, const char *le,
    const char *b, const char *e)
{
	const char *p;
	unsigned x, y;
	char c;

	x = y = 0;
	for (p = l; p < le && *p != '\n'; p++) {
		if (p >= b && p < e)
			c = '#';
		else
			c = '-';

		if (*p == '\t') {
			y &= ~7;
			y += 8;
		} else
			y++;
		while (x < y) {
			VSB_putc(tl->sb, c);
			x++;
		}
	}
	VSB_putc(tl->sb, '\n');
}

void
vcc_Warn(struct vcc *tl)
{

	AN(tl);
	AN(tl->err);
	VSB_cat(tl->sb, "(That was just a warning)\n");
	tl->err = 0;
}

/*--------------------------------------------------------------------*/
/* XXX: should take first+last token */

void
vcc_ErrWhere2(struct vcc *tl, const struct token *t, const struct token *t2)
{
	const char  *l1, *l2, *l3;

	if (t == NULL) {
		vcc_ErrWhere(tl, t2);
		return;
	}
	vcc_iline(t, &l1, 0);
	t2 = VTAILQ_PREV(t2, tokenhead, list);
	vcc_iline(t2, &l2, 1);


	if (l1 == l2) {
		vcc_icoord(tl->sb, t, 0);
		VSB_cat(tl->sb, " -- ");
		vcc_icoord(tl->sb, t2, 2);
		VSB_putc(tl->sb, '\n');
		/* Two tokens on same line */
		vcc_quoteline(tl, l1, t->src->e);
		vcc_markline(tl, l1, t->src->e, t->b, t2->e);
	} else {
		/* Two tokens different lines */
		l3 = strchr(l1, '\n');
		AN(l3);
		/* XXX: t had better be before t2 */
		vcc_icoord(tl->sb, t, 0);
		if (l3 + 1 == l2) {
			VSB_cat(tl->sb, " -- ");
			vcc_icoord(tl->sb, t2, 1);
		}
		VSB_putc(tl->sb, '\n');
		vcc_quoteline(tl, l1, t->src->e);
		vcc_markline(tl, l1, t->src->e, t->b, t2->e);
		if (l3 + 1 != l2) {
			VSB_cat(tl->sb, "[...]\n");
			vcc_icoord(tl->sb, t2, 1);
			VSB_putc(tl->sb, '\n');
		}
		vcc_quoteline(tl, l2, t->src->e);
		vcc_markline(tl, l2, t->src->e, t->b, t2->e);
	}
	VSB_putc(tl->sb, '\n');
	tl->err = 1;
}

void
vcc_ErrWhere(struct vcc *tl, const struct token *t)
{
	const char  *l1;

	vcc_iline(t, &l1, 0);
	vcc_icoord(tl->sb, t, 0);
	VSB_putc(tl->sb, '\n');
	vcc_quoteline(tl, l1, t->src->e);
	vcc_markline(tl, l1, t->src->e, t->b, t->e);
	VSB_putc(tl->sb, '\n');
	tl->err = 1;
}

/*--------------------------------------------------------------------*/

struct token *
vcc_PeekTokenFrom(const struct vcc *tl, const struct token *t)
{
	struct token *t2;

	CHECK_OBJ_NOTNULL(tl, VCC_MAGIC);
	AN(t);
	assert(t->tok != EOI);
	t2 = VTAILQ_NEXT(t, list);
	AN(t2);
	return (t2);
}

struct token *
vcc_PeekToken(const struct vcc *tl)
{

	CHECK_OBJ_NOTNULL(tl, VCC_MAGIC);
	return (vcc_PeekTokenFrom(tl, tl->t));
}

void
vcc_NextToken(struct vcc *tl)
{

	CHECK_OBJ_NOTNULL(tl, VCC_MAGIC);
	tl->t = vcc_PeekTokenFrom(tl, tl->t);
}

void
vcc__Expect(struct vcc *tl, unsigned tok, unsigned line)
{
	if (tl->t->tok == tok)
		return;
	VSB_printf(tl->sb, "Expected %s got ", vcl_tnames[tok]);
	vcc_ErrToken(tl, tl->t);
	VSB_printf(tl->sb, "\n(program line %u), at\n", line);
	vcc_ErrWhere(tl, tl->t);
}

/*--------------------------------------------------------------------
 * Compare ID token to string, return true of match
 */

int
vcc_IdIs(const struct token *t, const char *p)
{
	const char *q;

	assert(t->tok == ID);
	for (q = t->b; q < t->e && *p != '\0'; p++, q++)
		if (*q != *p)
			return (0);
	if (q != t->e || *p != '\0')
		return (0);
	return (1);
}

/*--------------------------------------------------------------------
 * Check that we have a Varnish identifier
 */

void
vcc_PrintTokens(const struct vcc *tl,
    const struct token *tb, const struct token *te)
{

	CHECK_OBJ_NOTNULL(tl, VCC_MAGIC);
	AN(tb);
	AN(te);
	while (tb != te) {
		VSB_printf(tl->sb, "%.*s", PF(tb));
		tb = vcc_PeekTokenFrom(tl, tb);
		AN(tb);
	}
}

void
vcc_ExpectVid(struct vcc *tl, const char *what)
{
	const char *bad = NULL;
	struct token *t2;

	ExpectErr(tl, ID);
	ERRCHK(tl);

	t2 = vcc_PeekToken(tl);
	AN(t2);
	while (t2->tok == '.') {
		bad = ".";
		t2 = vcc_PeekTokenFrom(tl, t2);
		AN(t2);
		if (t2->tok != ID)
			break;
		t2 = vcc_PeekTokenFrom(tl, t2);
		AN(t2);
	}
	if (bad == NULL)
		bad = VCT_invalid_name(tl->t->b, tl->t->e);
	if (bad != NULL) {
		VSB_printf(tl->sb, "Name of %s, '", what);
		vcc_PrintTokens(tl, tl->t, t2);
		VSB_printf(tl->sb,
		    "', contains illegal character '%c'\n", *bad);
		vcc_ErrWhere2(tl, tl->t, t2);
		return;
	}
}

/*--------------------------------------------------------------------
 * Decode a string
 */

static void
vcc_decstr(struct vcc *tl, unsigned sep)
{
	char *q;
	unsigned int l;

	assert(tl->t->tok == CSTR);
	l = pdiff(tl->t->b + sep, tl->t->e - sep);
	tl->t->dec = TlAlloc(tl, l + 1);
	AN(tl->t->dec);
	q = tl->t->dec;
	memcpy(q, tl->t->b + sep, l);
	q[l] = '\0';
}

/*--------------------------------------------------------------------
 * Add a token to the token list.
 */

static void
vcc_addtoken(struct vcc *tl, unsigned tok,
    struct source *sp, const char *b, const char *e)
{
	struct token *t;

	t = TlAlloc(tl, sizeof *t);
	assert(t != NULL);
	t->tok = tok;
	t->b = b;
	t->e = e;
	t->src = sp;
	VTAILQ_INSERT_TAIL(&sp->src_tokens, t, src_list);
	tl->t = t;
}

/*--------------------------------------------------------------------
 * Find a delimited token
 */

static const struct delim_def {
	const char	*name;
	const char	*b;
	const char	*e;
	unsigned	len;	/* NB: must be the same for both delimiters */
	unsigned	crlf;
	unsigned	tok;
} delim_defs[] = {
#define DELIM_DEF(nm, l, r, c, t)		\
	{ nm, l, r, sizeof (l) - 1, c, t }
	DELIM_DEF("long-string", "\"\"\"", "\"\"\"", 1, CSTR),	/* """...""" */
	DELIM_DEF("long-string", "{\"", "\"}", 1, CSTR),	/*  {"..."}  */
	DELIM_DEF("string", "\"", "\"", 0, CSTR),		/*   "..."   */
	DELIM_DEF("inline C source", "C{", "}C", 1, CSRC),	/*  C{...}C  */
#undef DELIM_DEF
	{ NULL }
};

static unsigned
vcc_delim_token(struct vcc *tl, struct source *sp, const char *p,
    const char **qp)
{
	const struct delim_def *dd;
	const char *q, *r;

	for (dd = delim_defs; dd->name != NULL; dd++)
		if (!strncmp(p, dd->b, dd->len))
			break;

	if (dd->name == NULL)
		return (0);

	q = strstr(p + dd->len, dd->e);
	if (q != NULL && !dd->crlf) {
		r = strpbrk(p + dd->len, "\r\n");
		if (r != NULL && r < q)
			q = NULL;
	}

	if (q == NULL) {
		vcc_addtoken(tl, EOI, sp, p, p + dd->len);
		VSB_printf(tl->sb, "Unterminated %s, starting at\n", dd->name);
		vcc_ErrWhere(tl, tl->t);
		return (0);
	}

	assert(q < sp->e);
	vcc_addtoken(tl, dd->tok, sp, p, q + dd->len);
	if (dd->tok == CSTR)
		vcc_decstr(tl, dd->len);
	*qp = q + dd->len;
	return (1);
}

/*--------------------------------------------------------------------
 * Lex a number, either CNUM or FNUM.
 * We enforce the RFC8941 restrictions on number of digits here.
 */

static const char *
vcc_lex_number(struct vcc *tl, struct source *sp, const char *p)
{
	const char *q, *r;
	char *s;

	for (q = p; q < sp->e; q++)
		if (!vct_isdigit(*q))
			break;
	if (*q != '.') {
		vcc_addtoken(tl, CNUM, sp, p, q);
		if (q - p > 15) {
			VSB_cat(tl->sb, "Too many digits for integer.\n");
			vcc_ErrWhere(tl, tl->t);
			return (NULL);
		}
		tl->t->num = strtod(p, &s);
		assert(s == tl->t->e);
		return (q);
	}
	r = ++q;
	for (; r < sp->e; r++)
		if (!vct_isdigit(*r))
			break;
	vcc_addtoken(tl, FNUM, sp, p, r);
	if (q - p > 13 || r - q > 3) {
		VSB_cat(tl->sb, "Too many digits for real.\n");
		vcc_ErrWhere(tl, tl->t);
		return (NULL);
	}
	if (*tl->t->e == 'e' || *tl->t->e == 'E') {
		VSB_printf(tl->sb, "Unexpected character '%c'.\n", *tl->t->e);
		tl->t->e++;
		vcc_ErrWhere(tl, tl->t);
		return (NULL);
	}
	tl->t->num = strtod(p, &s);
	assert(s == tl->t->e);
	return (r);
}

/*--------------------------------------------------------------------
 * Lexical analysis and token generation
 */

void
vcc_Lexer(struct vcc *tl, struct source *sp)
{
	const char *p, *q, *r;
	unsigned u;
	struct vsb *vsb;
	char namebuf[40];

	for (p = sp->b; p < sp->e; ) {

		/* Skip any whitespace */
		if (vct_isspace(*p)) {
			p++;
			continue;
		}

		/* Skip '#.*\n' comments */
		if (*p == '#') {
			while (p < sp->e && *p != '\n')
				p++;
			continue;
		}

		/* Skip C-style comments */
		if (*p == '/' && p[1] == '*') {
			for (q = p + 2; q < sp->e; q++) {
				if (*q == '/' && q[1] == '*') {
					VSB_cat(tl->sb,
					    "/* ... */ comment contains /*\n");
					vcc_addtoken(tl, EOI, sp, p, p + 2);
					vcc_ErrWhere(tl, tl->t);
					vcc_addtoken(tl, EOI, sp, q, q + 2);
					vcc_ErrWhere(tl, tl->t);
					return;
				}
				if (*q == '*' && q[1] == '/') {
					p = q + 2;
					break;
				}
			}
			if (q < sp->e)
				continue;
			vcc_addtoken(tl, EOI, sp, p, p + 2);
			VSB_cat(tl->sb,
			    "Unterminated /* ... */ comment, starting at\n");
			vcc_ErrWhere(tl, tl->t);
			return;
		}

		/* Skip C++-style comments */
		if (*p == '/' && p[1] == '/') {
			while (p < sp->e && *p != '\n')
				p++;
			continue;
		}

		/* Recognize BLOB (= SF-binary) */
		if (*p == ':') {
			vsb = VSB_new_auto();
			AN(vsb);
			q = sp->e;
			q -= (q - (p + 1)) % 4;
			assert(q > p);
			r = VENC_Decode_Base64(vsb, p + 1, q);
			if (r == NULL) {
				vcc_addtoken(tl, CBLOB, sp, p, q + 1);
				VSB_cat(tl->sb,
				    "Missing colon at end of BLOB:\n");
				vcc_ErrWhere(tl, tl->t);
				VSB_destroy(&vsb);
				return;
			}
			vcc_addtoken(tl, CBLOB, sp, p, r + 1);
			if (*r == ':' && ((r - p) % 4) != 1) {
				VSB_cat(tl->sb,
				    "BLOB must have n*4 base64 characters\n");
				vcc_ErrWhere(tl, tl->t);
				VSB_destroy(&vsb);
				return;
			}
			if (*r == '=') {
				VSB_cat(tl->sb,
				    "Wrong padding ('=') in BLOB:\n");
				vcc_ErrWhere(tl, tl->t);
				VSB_destroy(&vsb);
				return;
			}
			if (*r != ':') {
				VSB_cat(tl->sb, "Illegal BLOB character:\n");
				vcc_ErrWhere(tl, tl->t);
				VSB_destroy(&vsb);
				return;
			}
			r++;
			AZ(VSB_finish(vsb));

			bprintf(namebuf, "blob_%u", tl->unique++);
			Fh(tl, 0,
			    "\nstatic const unsigned char %s_data[%zd] = {\n",
			    namebuf, VSB_len(vsb));
			for (u = 0; u < VSB_len(vsb); u++) {
				Fh(tl, 0, "\t0x%02x,", VSB_data(vsb)[u] & 0xff);
				if ((u & 7) == 7)
					Fh(tl, 0, "\n");
			}
			if ((u & 7) != 7)
				Fh(tl, 0, "\n");
			Fh(tl, 0, "};\n");
			Fh(tl, 0,
			    "\nstatic const struct vrt_blob %s[1] = {{\n",
			    namebuf);
			Fh(tl, 0, "\t.len =\t%zd,\n", VSB_len(vsb));
			Fh(tl, 0, "\t.blob =\t%s_data,\n", namebuf);
			Fh(tl, 0, "}};\n");
			REPLACE(tl->t->dec, namebuf);
			VSB_destroy(&vsb);
			p = r;
			continue;
		}

		/* Match delimited tokens */
		if (vcc_delim_token(tl, sp, p, &q) != 0) {
			p = q;
			continue;
		}
		ERRCHK(tl);

		/* Match for the fixed tokens (see generate.py) */
		u = vcl_fixed_token(p, &q);
		if (u != 0) {
			vcc_addtoken(tl, u, sp, p, q);
			p = q;
			continue;
		}

		/* Match Identifiers */
		if (vct_isident1(*p)) {
			for (q = p; q < sp->e; q++)
				if (!vct_isident(*q))
					break;
			vcc_addtoken(tl, ID, sp, p, q);
			p = q;
			continue;
		}

		/* Match numbers { [0-9]+ } */
		if (vct_isdigit(*p)) {
			p = vcc_lex_number(tl, sp, p);
			if (p == NULL)
				return;
			continue;
		}
		vcc_addtoken(tl, EOI, sp, p, p + 1);
		VSB_cat(tl->sb, "Syntax error at\n");
		vcc_ErrWhere(tl, tl->t);
		return;
	}
	vcc_addtoken(tl, EOI, sp, sp->e, sp->e);
}