[PATCH 3/4] Change "ss" diff flag to an enum

[John Keeping]

This will allow us to introduce a new "stat only" diff mode without
needing an explosion of mutually incompatible flags.

The old "ss" query parameter is still accepted in order to avoid
breaking saved links, but we no longer generate any URIs using it;
instead the new "dt" (diff type) parameter is used.

Signed-off-by: John Keeping <john at keeping.me.uk>
---
 cgit.c      | 12 ++++++++----
 cgit.h      | 10 +++++++---
 ui-diff.c   |  8 +++++---
 ui-shared.c |  8 ++++----
 4 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/cgit.c b/cgit.c
index 8c4517d..db60107 100644
--- a/cgit.c
+++ b/cgit.c
@@ -237,7 +237,7 @@ static void config_cb(const char *name, const char *value)
 	else if (!strcmp(name, "summary-tags"))
 		ctx.cfg.summary_tags = atoi(value);
 	else if (!strcmp(name, "side-by-side-diffs"))
-		ctx.cfg.ssdiff = atoi(value);
+		ctx.cfg.difftype = atoi(value) ? DIFF_SSDIFF : DIFF_UNIFIED;
 	else if (!strcmp(name, "agefile"))
 		ctx.cfg.agefile = xstrdup(value);
 	else if (!strcmp(name, "mimetype-file"))
@@ -312,9 +312,13 @@ static void querystring_cb(const char *name, const char *value)
 		ctx.qry.showmsg = atoi(value);
 	} else if (!strcmp(name, "period")) {
 		ctx.qry.period = xstrdup(value);
+	} else if (!strcmp(name, "dt")) {
+		ctx.qry.difftype = atoi(value);
+		ctx.qry.has_difftype = 1;
 	} else if (!strcmp(name, "ss")) {
-		ctx.qry.ssdiff = atoi(value);
-		ctx.qry.has_ssdiff = 1;
+		/* No longer generated, but there may be links out there. */
+		ctx.qry.difftype = atoi(value) ? DIFF_SSDIFF : DIFF_UNIFIED;
+		ctx.qry.has_difftype = 1;
 	} else if (!strcmp(name, "all")) {
 		ctx.qry.show_all = atoi(value);
 	} else if (!strcmp(name, "context")) {
@@ -372,7 +376,7 @@ static void prepare_context(void)
 	ctx.cfg.summary_log = 10;
 	ctx.cfg.summary_tags = 10;
 	ctx.cfg.max_atom_items = 10;
-	ctx.cfg.ssdiff = 0;
+	ctx.cfg.difftype = DIFF_UNIFIED;
 	ctx.env.cgit_config = getenv("CGIT_CONFIG");
 	ctx.env.http_host = getenv("HTTP_HOST");
 	ctx.env.https = getenv("HTTPS");
diff --git a/cgit.h b/cgit.h
index 0badc64..0eb5ed5 100644
--- a/cgit.h
+++ b/cgit.h
@@ -53,6 +53,10 @@ typedef void (*filepair_fn)(struct diff_filepair *pair);
 typedef void (*linediff_fn)(char *line, int len);
 
 typedef enum {
+	DIFF_UNIFIED, DIFF_SSDIFF
+} diff_type;
+
+typedef enum {
 	ABOUT, COMMIT, SOURCE, EMAIL, AUTH
 } filter_type;
 
@@ -150,7 +154,7 @@ struct reflist {
 struct cgit_query {
 	int has_symref;
 	int has_sha1;
-	int has_ssdiff;
+	int has_difftype;
 	char *raw;
 	char *repo;
 	char *page;
@@ -168,7 +172,7 @@ struct cgit_query {
 	int nohead;
 	char *sort;
 	int showmsg;
-	int ssdiff;
+	diff_type difftype;
 	int show_all;
 	int context;
 	int ignorews;
@@ -245,7 +249,7 @@ struct cgit_config {
 	int summary_branches;
 	int summary_log;
 	int summary_tags;
-	int ssdiff;
+	diff_type difftype;
 	int branch_sort;
 	int commit_sort;
 	struct string_list mimetypes;
diff --git a/ui-diff.c b/ui-diff.c
index 49bd748..a4ade4d 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -345,8 +345,8 @@ void cgit_print_diff_ctrls()
 	html("</tr><tr>");
 	html("<td class='label'>mode:</td>");
 	html("<td class='ctrl'>");
-	html("<select name='ss' onchange='this.form.submit();'>");
-	curr = ctx.qry.has_ssdiff ? ctx.qry.ssdiff : ctx.cfg.ssdiff;
+	html("<select name='dt' onchange='this.form.submit();'>");
+	curr = ctx.qry.has_difftype ? ctx.qry.difftype : ctx.cfg.difftype;
 	html_intoption(0, "unified", curr);
 	html_intoption(1, "ssdiff", curr);
 	html("</select></td></tr>");
@@ -362,6 +362,7 @@ void cgit_print_diff(const char *new_rev, const char *old_rev,
 {
 	struct commit *commit, *commit2;
 	const unsigned char *old_tree_sha1, *new_tree_sha1;
+	diff_type difftype;
 
 	if (!new_rev)
 		new_rev = ctx.qry.head;
@@ -420,7 +421,8 @@ void cgit_print_diff(const char *new_rev, const char *old_rev,
 		return;
 	}
 
-	use_ssdiff = ctx.qry.has_ssdiff ? ctx.qry.ssdiff : ctx.cfg.ssdiff;
+	difftype = ctx.qry.has_difftype ? ctx.qry.difftype : ctx.cfg.difftype;
+	use_ssdiff = difftype == DIFF_SSDIFF;
 
 	if (show_ctrls)
 		cgit_print_diff_ctrls();
diff --git a/ui-shared.c b/ui-shared.c
index 68e0d7c..6243d1b 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -346,9 +346,9 @@ void cgit_commit_link(char *name, const char *title, const char *class,
 		html_url_arg(rev);
 		delim = "&";
 	}
-	if (ctx.qry.ssdiff) {
+	if (ctx.qry.difftype) {
 		html(delim);
-		html("ss=1");
+		htmlf("dt=%d", ctx.qry.difftype);
 		delim = "&";
 	}
 	if (ctx.qry.context > 0 && ctx.qry.context != 3) {
@@ -402,9 +402,9 @@ void cgit_diff_link(const char *name, const char *title, const char *class,
 		html_url_arg(old_rev);
 		delim = "&";
 	}
-	if (ctx.qry.ssdiff) {
+	if (ctx.qry.difftype) {
 		html(delim);
-		html("ss=1");
+		htmlf("dt=%d", ctx.qry.difftype);
 		delim = "&";
 	}
 	if (ctx.qry.context > 0 && ctx.qry.context != 3) {
-- 
2.1.0.374.g390713e