Support a second argument to -O man,

selecting the format according to local existence of the file.
Suggested by kristaps@ during EuroBSDCon 2018.
Written on the train Frankfurt-Karlsruhe returning from EuroBSDCon.

5 files changed, 26 insertions, 11 deletions

diff --git a/TODO b/TODO
index a66c5bd3..4aded6d4 100644
--- a/TODO
+++ b/TODO
@@ -395,12 +395,6 @@ are mere guesses, and some may be wrong.
   only if the new option -O toc is given
   suggested by Adam Kalisz during EuroBSDCon 2018
 
-- support -O man with two arguments, typically using the first for
-  a local tree (like the release pages on mandoc.bsd.lv) and the
-  second for a remote tree (e.g. man.openbsd.org).
-  Probable syntax: -O man=first;second
-  Suggested by kristaps@ during EuroBSDCon 2018.
-
 - wrap Sh and Ss content into <div>
   Laura Morales <lauretas at mail dot com> 21 Apr 2018 18:10:48 +0200
   (Evaluate whether this is really useful and has no adverse
diff --git a/html.c b/html.c
index 778e7953..d0c2b656 100644
--- a/html.c
+++ b/html.c
@@ -18,6 +18,7 @@
 #include "config.h"
 
 #include <sys/types.h>
+#include <sys/stat.h>
 
 #include <assert.h>
 #include <ctype.h>
@@ -128,7 +129,10 @@ html_alloc(const struct manoutput *outopts)
 
 	h->tag = NULL;
 	h->style = outopts->style;
-	h->base_man = outopts->man;
+	if ((h->base_man1 = outopts->man) == NULL)
+		h->base_man2 = NULL;
+	else if ((h->base_man2 = strchr(h->base_man1, ';')) != NULL)
+		*h->base_man2++ = '\0';
 	h->base_includes = outopts->includes;
 	if (outopts->fragment)
 		h->oflags |= HTML_FRAGMENT;
@@ -467,9 +471,21 @@ print_encode(struct html *h, const char *p, const char *pend, int norecurse)
 static void
 print_href(struct html *h, const char *name, const char *sec, int man)
 {
+	struct stat	 sb;
 	const char	*p, *pp;
+	char		*filename;
+
+	if (man) {
+		pp = h->base_man1;
+		if (h->base_man2 != NULL) {
+			mandoc_asprintf(&filename, "%s.%s", name, sec);
+			if (stat(filename, &sb) == -1)
+				pp = h->base_man2;
+			free(filename);
+		}
+	} else
+		pp = h->base_includes;
 
-	pp = man ? h->base_man : h->base_includes;
 	while ((p = strchr(pp, '%')) != NULL) {
 		print_encode(h, pp, p, 1);
 		if (man && p[1] == 'S') {
diff --git a/html.h b/html.h
index 84d88dc9..4b3e3df1 100644
--- a/html.h
+++ b/html.h
@@ -101,7 +101,8 @@ struct	html {
 	struct tag	 *tag; /* last open tag */
 	struct rofftbl	  tbl; /* current table */
 	struct tag	 *tblt; /* current open table scope */
-	char		 *base_man; /* base for manpage href */
+	char		 *base_man1; /* bases for manpage href */
+	char		 *base_man2;
 	char		 *base_includes; /* base for include href */
 	char		 *style; /* style-sheet URI */
 	struct tag	 *metaf; /* current open font scope */
diff --git a/mandoc.1 b/mandoc.1
index 4cdfe150..afea0a1b 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -345,7 +345,7 @@ Instances of
 are replaced with the include filename.
 The default is not to present a
 hyperlink.
-.It Cm man Ns = Ns Ar fmt
+.It Cm man Ns = Ns Ar fmt Ns Op ; Ns Ar fmt
 The string
 .Ar fmt ,
 for example,
@@ -361,6 +361,10 @@ are replaced with the linked manual's name and section, respectively.
 If no section is included, section 1 is assumed.
 The default is not to
 present a hyperlink.
+If two formats are given and a file
+.Ar %N.%S
+exists in the current directory, the first format is used;
+otherwise, the second format is used.
 .It Cm style Ns = Ns Ar style.css
 The file
 .Ar style.css
diff --git a/mdoc_html.c b/mdoc_html.c
index 7974605e..c66160df 100644
--- a/mdoc_html.c
+++ b/mdoc_html.c
@@ -611,7 +611,7 @@ mdoc_xr_pre(MDOC_ARGS)
 	if (NULL == n->child)
 		return 0;
 
-	if (h->base_man)
+	if (h->base_man1)
 		print_otag(h, TAG_A, "cThM", "Xr",
 		    n->child->string, n->child->next == NULL ?
 		    NULL : n->child->next->string);