In HTML output, allow switching the desired font for subsequent

text without printing an opening tag right away, and use that in
the .ft request handler.  While here, garbage collect redundant
enum htmlfont and reduce code duplication in print_text().
Fixing an assertion failure reported by Michael <Stapelberg at Debian>
in pmRegisterDerived(3) from libpcp3-dev.

5 files changed, 39 insertions, 71 deletions

diff --git a/regress/usr.bin/mandoc/roff/ft/badargs.out_html b/regress/usr.bin/mandoc/roff/ft/badargs.out_html
index 5d98e9883a6..0fa4a816460 100644
--- a/regress/usr.bin/mandoc/roff/ft/badargs.out_html
+++ b/regress/usr.bin/mandoc/roff/ft/badargs.out_html
@@ -1,9 +1,8 @@
 BEGINTEST
 <br/>
-default font <i></i><i>italic</i> <b><i></i></b><b><i>bold italic</i></b>
-  <span class="Li"></span><span class="Li">typeqriter</span>
-  <span class="Li"></span> <span class="Li">roman</span> <b></b><b>bold</b>
-  <i></i> <i>italic</i> <b></b><b>bold</b> <b>still bold</b>
-  <i></i><i>italic</i> <i></i><i>back to bold</i> <i></i><i>back to italic</i>
+default font <i>italic</i> <b><i>bold italic</i></b>
+  <span class="Li">typeqriter</span> <span class="Li">roman</span> <b>bold</b>
+  <i>italic</i> <b>bold</b> <b>still bold</b> <i>italic</i> <i>back to bold</i>
+  <i>back to italic</i>
 <br/>
 ENDTEST
diff --git a/usr.bin/mandoc/html.c b/usr.bin/mandoc/html.c
index 1d2e308a55b..b6c1ce12587 100644
--- a/usr.bin/mandoc/html.c
+++ b/usr.bin/mandoc/html.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: html.c,v 1.124 2019/03/03 13:01:47 schwarze Exp $ */
+/*	$OpenBSD: html.c,v 1.125 2019/04/30 15:52:42 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2011-2015, 2017-2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -118,6 +118,7 @@ static	void	 print_ctag(struct html *, struct tag *);
 static	int	 print_escape(struct html *, char);
 static	int	 print_encode(struct html *, const char *, const char *, int);
 static	void	 print_href(struct html *, const char *, const char *, int);
+static	void	 print_metaf(struct html *);
 
 
 void *
@@ -220,55 +221,49 @@ print_gen_head(struct html *h)
 	print_tagq(h, t);
 }
 
-void
-print_metaf(struct html *h, enum mandoc_esc deco)
+int
+html_setfont(struct html *h, enum mandoc_esc font)
 {
-	enum htmlfont	 font;
-
-	switch (deco) {
+	switch (font) {
 	case ESCAPE_FONTPREV:
 		font = h->metal;
 		break;
 	case ESCAPE_FONTITALIC:
-		font = HTMLFONT_ITALIC;
-		break;
 	case ESCAPE_FONTBOLD:
-		font = HTMLFONT_BOLD;
-		break;
 	case ESCAPE_FONTBI:
-		font = HTMLFONT_BI;
-		break;
 	case ESCAPE_FONTCW:
-		font = HTMLFONT_CW;
+	case ESCAPE_FONTROMAN:
 		break;
 	case ESCAPE_FONT:
-	case ESCAPE_FONTROMAN:
-		font = HTMLFONT_NONE;
+		font = ESCAPE_FONTROMAN;
 		break;
 	default:
-		return;
+		return 0;
 	}
+	h->metal = h->metac;
+	h->metac = font;
+	return 1;
+}
 
+static void
+print_metaf(struct html *h)
+{
 	if (h->metaf) {
 		print_tagq(h, h->metaf);
 		h->metaf = NULL;
 	}
-
-	h->metal = h->metac;
-	h->metac = font;
-
-	switch (font) {
-	case HTMLFONT_ITALIC:
+	switch (h->metac) {
+	case ESCAPE_FONTITALIC:
 		h->metaf = print_otag(h, TAG_I, "");
 		break;
-	case HTMLFONT_BOLD:
+	case ESCAPE_FONTBOLD:
 		h->metaf = print_otag(h, TAG_B, "");
 		break;
-	case HTMLFONT_BI:
+	case ESCAPE_FONTBI:
 		h->metaf = print_otag(h, TAG_B, "");
 		print_otag(h, TAG_I, "");
 		break;
-	case HTMLFONT_CW:
+	case ESCAPE_FONTCW:
 		h->metaf = print_otag(h, TAG_SPAN, "c", "Li");
 		break;
 	default:
@@ -477,7 +472,8 @@ print_encode(struct html *h, const char *p, const char *pend, int norecurse)
 		case ESCAPE_FONTROMAN:
 			if (0 == norecurse) {
 				h->flags |= HTML_NOSPACE;
-				print_metaf(h, esc);
+				if (html_setfont(h, esc))
+					print_metaf(h);
 				h->flags &= ~HTML_NOSPACE;
 			}
 			continue;
@@ -804,27 +800,9 @@ print_text(struct html *h, const char *word)
 			print_word(h, "&#x00A0;");
 	}
 
-	assert(NULL == h->metaf);
-	switch (h->metac) {
-	case HTMLFONT_ITALIC:
-		h->metaf = print_otag(h, TAG_I, "");
-		break;
-	case HTMLFONT_BOLD:
-		h->metaf = print_otag(h, TAG_B, "");
-		break;
-	case HTMLFONT_BI:
-		h->metaf = print_otag(h, TAG_B, "");
-		print_otag(h, TAG_I, "");
-		break;
-	case HTMLFONT_CW:
-		h->metaf = print_otag(h, TAG_SPAN, "c", "Li");
-		break;
-	default:
-		print_indent(h);
-		break;
-	}
-
-	assert(word);
+	assert(h->metaf == NULL);
+	print_metaf(h);
+	print_indent(h);
 	if ( ! print_encode(h, word, NULL, 0)) {
 		if ( ! (h->flags & HTML_NONOSPACE))
 			h->flags &= ~HTML_NOSPACE;
@@ -832,7 +810,7 @@ print_text(struct html *h, const char *word)
 	} else
 		h->flags |= HTML_NOSPACE | HTML_NONEWLINE;
 
-	if (h->metaf) {
+	if (h->metaf != NULL) {
 		print_tagq(h, h->metaf);
 		h->metaf = NULL;
 	}
diff --git a/usr.bin/mandoc/html.h b/usr.bin/mandoc/html.h
index 253a2423523..71bcf3b5b03 100644
--- a/usr.bin/mandoc/html.h
+++ b/usr.bin/mandoc/html.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: html.h,v 1.64 2019/03/01 10:48:58 schwarze Exp $ */
+/*	$OpenBSD: html.h,v 1.65 2019/04/30 15:52:42 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2017, 2018, 2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -69,15 +69,6 @@ enum	htmltag {
 	TAG_MAX
 };
 
-enum	htmlfont {
-	HTMLFONT_NONE = 0,
-	HTMLFONT_BOLD,
-	HTMLFONT_ITALIC,
-	HTMLFONT_BI,
-	HTMLFONT_CW,
-	HTMLFONT_MAX
-};
-
 struct	tag {
 	struct tag	 *next;
 	int		  refcnt;
@@ -111,8 +102,8 @@ struct	html {
 	char		 *base_includes; /* base for include href */
 	char		 *style; /* style-sheet URI */
 	struct tag	 *metaf; /* current open font scope */
-	enum htmlfont	  metal; /* last used font */
-	enum htmlfont	  metac; /* current font mode */
+	enum mandoc_esc	  metal; /* last used font */
+	enum mandoc_esc	  metac; /* current font mode */
 	int		  oflags; /* output options */
 #define	HTML_FRAGMENT	 (1 << 0) /* don't emit HTML/HEAD/BODY */
 #define	HTML_TOC	 (1 << 1) /* emit a table of contents */
@@ -128,7 +119,6 @@ void		  roff_html_pre(struct html *, const struct roff_node *);
 void		  print_gen_comment(struct html *, struct roff_node *);
 void		  print_gen_decls(struct html *);
 void		  print_gen_head(struct html *);
-void		  print_metaf(struct html *, enum mandoc_esc);
 struct tag	 *print_otag(struct html *, enum htmltag, const char *, ...);
 void		  print_tagq(struct html *, const struct tag *);
 void		  print_stagq(struct html *, const struct tag *);
@@ -141,3 +131,4 @@ void		  print_endline(struct html *);
 void		  html_close_paragraph(struct html *);
 enum roff_tok	  html_fillmode(struct html *, enum roff_tok);
 char		 *html_make_id(const struct roff_node *, int);
+int		  html_setfont(struct html *, enum mandoc_esc);
diff --git a/usr.bin/mandoc/man_html.c b/usr.bin/mandoc/man_html.c
index 7ce331ecb7e..5c51897edd5 100644
--- a/usr.bin/mandoc/man_html.c
+++ b/usr.bin/mandoc/man_html.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: man_html.c,v 1.126 2019/03/02 16:29:49 schwarze Exp $ */
+/*	$OpenBSD: man_html.c,v 1.127 2019/04/30 15:52:42 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2013-2015, 2017-2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -201,9 +201,9 @@ print_man_node(MAN_ARGS)
 		 * Close out scope of font prior to opening a macro
 		 * scope.
 		 */
-		if (HTMLFONT_NONE != h->metac) {
+		if (h->metac != ESCAPE_FONTROMAN) {
 			h->metal = h->metac;
-			h->metac = HTMLFONT_NONE;
+			h->metac = ESCAPE_FONTROMAN;
 		}
 
 		/*
diff --git a/usr.bin/mandoc/roff_html.c b/usr.bin/mandoc/roff_html.c
index f2f7258245b..ed9639a3aeb 100644
--- a/usr.bin/mandoc/roff_html.c
+++ b/usr.bin/mandoc/roff_html.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: roff_html.c,v 1.19 2019/01/07 06:51:37 schwarze Exp $ */
+/*	$OpenBSD: roff_html.c,v 1.20 2019/04/30 15:52:42 schwarze Exp $ */
 /*
  * Copyright (c) 2010 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2017, 2018, 2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -94,7 +94,7 @@ roff_html_pre_ft(ROFF_HTML_ARGS)
 	const char	*cp;
 
 	cp = n->child->string;
-	print_metaf(h, mandoc_font(cp, (int)strlen(cp)));
+	html_setfont(h, mandoc_font(cp, (int)strlen(cp)));
 }
 
 static void