Use <pre> and <span> to print diffs

This correctly preserves whitespace in browsers without CSS, as an
alternative to [1].

[1]: https://80x24.org/cgit.git/commit/?id=7c692e6137697de8a8473c4de5c3de4fb03a2989

2 files changed, 21 insertions, 23 deletions

diff --git a/www/git.causal.agency/cgit/cgit.css b/www/git.causal.agency/cgit/cgit.css
index dac791b6..36826b07 100644
--- a/www/git.causal.agency/cgit/cgit.css
+++ b/www/git.causal.agency/cgit/cgit.css
@@ -533,26 +533,20 @@ div#cgit table.diff {
 	width: 100%;
 }
 
-div#cgit table.diff td {
-	font-family: monospace;
-	white-space: pre;
-}
-
-div#cgit table.diff td div.head {
+div#cgit table.diff td span.head {
 	font-weight: bold;
-	margin-top: 1em;
 	color: black;
 }
 
-div#cgit table.diff td div.hunk {
+div#cgit table.diff td span.hunk {
 	color: #009;
 }
 
-div#cgit table.diff td div.add {
+div#cgit table.diff td span.add {
 	color: green;
 }
 
-div#cgit table.diff td div.del {
+div#cgit table.diff td span.del {
 	color: red;
 }
 
diff --git a/www/git.causal.agency/cgit/ui-diff.c b/www/git.causal.agency/cgit/ui-diff.c
index 329c3506..97c1ca02 100644
--- a/www/git.causal.agency/cgit/ui-diff.c
+++ b/www/git.causal.agency/cgit/ui-diff.c
@@ -231,11 +231,11 @@ static void print_line(char *line, int len)
 	else if (line[0] == '@')
 		class = "hunk";
 
-	htmlf("<div class='%s'>", class);
+	htmlf("<span class='%s'>", class);
 	line[len-1] = '\0';
 	html_txt(line);
-	html("</div>");
 	line[len-1] = c;
+	html("</span>\n");
 }
 
 static void header(const struct object_id *oid1, char *path1, int mode1,
@@ -245,22 +245,23 @@ static void header(const struct object_id *oid1, char *path1, int mode1,
 	int subproject;
 
 	subproject = (S_ISGITLINK(mode1) || S_ISGITLINK(mode2));
-	html("<div class='head'>");
+	html("<span class='head'>");
 	html("diff --git a/");
 	html_txt(path1);
 	html(" b/");
 	html_txt(path2);
+	html("\n");
 
 	if (mode1 == 0)
-		htmlf("<br/>new file mode %.6o", mode2);
+		htmlf("new file mode %.6o\n", mode2);
 
 	if (mode2 == 0)
-		htmlf("<br/>deleted file mode %.6o", mode1);
+		htmlf("deleted file mode %.6o\n", mode1);
 
 	if (!subproject) {
 		abbrev1 = xstrdup(find_unique_abbrev(oid1, DEFAULT_ABBREV));
 		abbrev2 = xstrdup(find_unique_abbrev(oid2, DEFAULT_ABBREV));
-		htmlf("<br/>index %s..%s", abbrev1, abbrev2);
+		htmlf("index %s..%s", abbrev1, abbrev2);
 		free(abbrev1);
 		free(abbrev2);
 		if (mode1 != 0 && mode2 != 0) {
@@ -268,28 +269,31 @@ static void header(const struct object_id *oid1, char *path1, int mode1,
 			if (mode2 != mode1)
 				htmlf("..%.6o", mode2);
 		}
+		html("\n");
 		if (is_null_oid(oid1)) {
 			path1 = "dev/null";
-			html("<br/>--- /");
+			html("--- /");
 		} else
-			html("<br/>--- a/");
+			html("--- a/");
 		if (mode1 != 0)
 			cgit_tree_link(path1, NULL, NULL, ctx.qry.head,
 				       oid_to_hex(old_rev_oid), path1);
 		else
 			html_txt(path1);
+		html("\n");
 		if (is_null_oid(oid2)) {
 			path2 = "dev/null";
-			html("<br/>+++ /");
+			html("+++ /");
 		} else
-			html("<br/>+++ b/");
+			html("+++ b/");
 		if (mode2 != 0)
 			cgit_tree_link(path2, NULL, NULL, ctx.qry.head,
 				       oid_to_hex(new_rev_oid), path2);
 		else
 			html_txt(path2);
+		html("\n");
 	}
-	html("</div>");
+	html("</span>");
 }
 
 static void filepair_cb(struct diff_filepair *pair)
@@ -488,12 +492,12 @@ void cgit_print_diff(const char *new_rev, const char *old_rev,
 		html("<table summary='ssdiff' class='ssdiff'>");
 	} else {
 		html("<table summary='diff' class='diff'>");
-		html("<tr><td>");
+		html("<tr><td><pre>");
 	}
 	cgit_diff_tree(old_rev_oid, new_rev_oid, filepair_cb, prefix,
 		       ctx.qry.ignorews);
 	if (!use_ssdiff)
-		html("</td></tr>");
+		html("</pre></td></tr>");
 	html("</table>");
 
 	if (show_ctrls)