Allow arguments for diff-highlight

This allows users to specify arguments in their ~/.tigrc when using an
alternate `diff-highlight` program.

NEWS.adoc

@@ -1,6 +1,13 @@
 Release notes
 =============
 
+master
+------
+
+Improvements:
+
+ - Allow arguments for `diff-highlight`.
+
 tig-2.5.12
 ----------
 

include/tig/apps.h

@@ -31,7 +31,7 @@ struct app_external {
  * diff-highlight
  */
 
-struct app_external *app_diff_highlight_load(const char *query);
+struct app_external *app_diff_highlight_load(const char **query);
 
 #endif
 

include/tig/options.h

@@ -38,7 +38,7 @@ typedef struct view_column *view_settings;
 	_(diff_context,			int,			VIEW_DIFF_LIKE) \
 	_(diff_noprefix,		bool,			VIEW_NO_FLAGS) \
 	_(diff_options,			const char **,		VIEW_DIFF_LIKE) \
-	_(diff_highlight,		const char *,		VIEW_DIFF_LIKE) \
+	_(diff_highlight,		const char **,		VIEW_DIFF_LIKE) \
 	_(word_diff,			bool,			VIEW_DIFF_LIKE) \
 	_(diff_view,			view_settings,		VIEW_NO_FLAGS) \
 	_(editor_line_number,		bool,			VIEW_NO_FLAGS) \

src/apps.c

@@ -95,7 +95,7 @@ app_diff_highlight_path_search(char *dest, size_t destlen, const char *query)
 }
 
 struct app_external
-*app_diff_highlight_load(const char *query)
+*app_diff_highlight_load(const char **query)
 {
 	static struct app_external dhlt_app = { { NULL }, { "GIT_CONFIG=/dev/null", NULL } };
 	static bool did_search = false;
@@ -104,11 +104,14 @@ struct app_external
 	static char perl_include[SIZEOF_STR];
 
 	if (!did_search
-	    && app_diff_highlight_path_search(dhlt_path, sizeof(dhlt_path), query)
+	    && app_diff_highlight_path_search(dhlt_path, sizeof(dhlt_path), *query)
 	    && *dhlt_path) {
 		if (suffixcmp(dhlt_path, strlen(dhlt_path), "/diff-highlight.perl")) {
+			int i;
 			dhlt_app.argv[0] = dhlt_path;
-			dhlt_app.argv[1] = NULL;
+			for (i = 1; query[i] && i < SIZEOF_ARG; i++)
+				dhlt_app.argv[i] = query[i];
+			dhlt_app.argv[i] = NULL;
 		} else if (path_search(perl_path, sizeof(perl_path), "perl", getenv("PATH"), X_OK)) {
 			/* if the package manager failed to "make install" within the contrib dir, rescue via */
 			/* perl -MDiffHighlight -I/path/containing /path/containing/diff-highlight.perl */

src/diff.c

@@ -62,7 +62,7 @@ diff_init_highlight(struct view *view, struct diff_state *state)
 		app->argv[0] = "";
 
 	if (!io_exec(&io, IO_RP, view->dir, app->env, app->argv, view->io.pipe))
-		return error("Failed to run %s", opt_diff_highlight);
+		return error("Failed to run %s", *opt_diff_highlight);
 
 	state->view_io = view->io;
 	view->io = io;
@@ -521,7 +521,7 @@ diff_read(struct view *view, struct buffer *buf, bool force_stop)
 	if (!buf) {
 		if (!diff_done_highlight(state)) {
 			if (!force_stop)
-				report("Failed to run the diff-highlight program: %s", opt_diff_highlight);
+				report("Failed to run the diff-highlight program: %s", *opt_diff_highlight);
 			return false;
 		}
 

src/options.c

@@ -636,6 +636,18 @@ parse_encoding(struct encoding **encoding_ref, const char *arg, bool priority)
 static enum status_code
 parse_args(const char ***args, const char *argv[])
 {
+	if (args == &opt_diff_highlight && *argv) {
+		bool enabled = false;
+
+		if (parse_bool(&enabled, *argv) == SUCCESS) {
+			if (!enabled) {
+				argv_free(*args);
+				return SUCCESS;
+			}
+			*argv = "diff-highlight";
+		}
+	}
+
 	if (!argv_copy(args, argv))
 		return ERROR_OUT_OF_MEMORY;
 	return SUCCESS;
@@ -733,18 +745,6 @@ parse_option(struct option_info *option, const char *prefix, const char *arg)
 		const char **value = option->value;
 		char *alloc = NULL;
 
-		if (option->value == &opt_diff_highlight) {
-			bool enabled = false;
-
-			if (parse_bool(&enabled, arg) == SUCCESS) {
-				if (!enabled) {
-					*value = NULL;
-					return SUCCESS;
-				}
-				arg = "diff-highlight";
-			}
-		}
-
 		if (strlen(arg)) {
 			if (arg[0] == '"' && arg[strlen(arg) - 1] == '"')
 				alloc = strndup(arg + 1, strlen(arg + 1) - 1);

src/pager.c

@@ -143,7 +143,7 @@ pager_read(struct view *view, struct buffer *buf, bool force_stop)
 	if (!buf) {
 		if (!diff_done_highlight(view->private)) {
 			if (!force_stop)
-				report("Failed to run the diff-highlight program: %s", opt_diff_highlight);
+				report("Failed to run the diff-highlight program: %s", *opt_diff_highlight);
 			return false;
 		}
 

src/stage.c

@@ -799,7 +799,7 @@ stage_read(struct view *view, struct buffer *buf, bool force_stop)
 	if (!buf) {
 		if (!diff_done_highlight(&state->diff)) {
 			if (!force_stop)
-				report("Failed to run the diff-highlight program: %s", opt_diff_highlight);
+				report("Failed to run the diff-highlight program: %s", *opt_diff_highlight);
 			return false;
 		}