diff: mark unused parameters in callbacks

The diff code provides a format_callback interface, but not every
callback needs each parameter (e.g., the "opt" and "data" parameters are
frequently left unused). Likewise for the output_prefix callback, the
low-level change/add_remove interfaces, the callbacks used by
xdi_diff(), etc.

Mark unused arguments in the callback implementations to quiet
-Wunused-parameter.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

add-interactive.c

@@ -724,7 +724,7 @@ static int run_update(struct add_i_state *s, const struct pathspec *ps,
 }
 
 static void revert_from_diff(struct diff_queue_struct *q,
-			     struct diff_options *opt, void *data)
+			     struct diff_options *opt, void *data UNUSED)
 {
 	int i, add_flags = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 

builtin/add.c

@@ -88,7 +88,7 @@ static int fix_unmerged_status(struct diff_filepair *p,
 }
 
 static void update_callback(struct diff_queue_struct *q,
-			    struct diff_options *opt, void *cbdata)
+			    struct diff_options *opt UNUSED, void *cbdata)
 {
 	int i;
 	struct update_callback_data *data = cbdata;

builtin/fast-export.c

@@ -409,7 +409,7 @@ static const char *anonymize_oid(const char *oid_hex)
 }
 
 static void show_filemodify(struct diff_queue_struct *q,
-			    struct diff_options *options, void *data)
+			    struct diff_options *options UNUSED, void *data)
 {
 	int i;
 	struct string_list *changed = data;

builtin/merge-tree.c

@@ -98,7 +98,7 @@ static void *origin(struct merge_list *entry, unsigned long *size)
 	return NULL;
 }
 
-static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf)
+static int show_outf(void *priv UNUSED, mmbuffer_t *mb, int nbuf)
 {
 	int i;
 	for (i = 0; i < nbuf; i++)

builtin/merge.c

@@ -776,7 +776,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 }
 
 static void count_diff_files(struct diff_queue_struct *q,
-			     struct diff_options *opt, void *data)
+			     struct diff_options *opt UNUSED, void *data)
 {
 	int *count = data;
 

builtin/rerere.c

@@ -14,7 +14,7 @@ static const char * const rerere_usage[] = {
 	NULL,
 };
 
-static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
+static int outf(void *dummy UNUSED, mmbuffer_t *ptr, int nbuf)
 {
 	int i;
 	for (i = 0; i < nbuf; i++)

builtin/reset.c

@@ -133,7 +133,8 @@ static void print_new_head_line(struct commit *commit)
 }
 
 static void update_index_from_diff(struct diff_queue_struct *q,
-		struct diff_options *opt, void *data)
+				   struct diff_options *opt UNUSED,
+				   void *data)
 {
 	int i;
 	int intent_to_add = *(int *)data;

builtin/submodule--helper.c

@@ -1043,7 +1043,7 @@ static void prepare_submodule_summary(struct summary_cb *info,
 }
 
 static void submodule_summary_callback(struct diff_queue_struct *q,
-				       struct diff_options *options,
+				       struct diff_options *options UNUSED,
 				       void *data)
 {
 	int i;

combine-diff.c

@@ -372,7 +372,7 @@ struct combine_diff_state {
 static void consume_hunk(void *state_,
 			 long ob, long on,
 			 long nb, long nn,
-			 const char *funcline, long funclen)
+			 const char *func UNUSED, long funclen UNUSED)
 {
 	struct combine_diff_state *state = state_;
 

diff-lib.c

@@ -673,7 +673,7 @@ int index_differs_from(struct repository *r,
 	return (has_changes != 0);
 }
 
-static struct strbuf *idiff_prefix_cb(struct diff_options *opt, void *data)
+static struct strbuf *idiff_prefix_cb(struct diff_options *opt UNUSED, void *data)
 {
 	return data;
 }

diff.c

@@ -1954,7 +1954,7 @@ static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 static void fn_out_diff_words_aux(void *priv,
 				  long minus_first, long minus_len,
 				  long plus_first, long plus_len,
-				  const char *func, long funclen)
+				  const char *func UNUSED, long funclen UNUSED)
 {
 	struct diff_words_data *diff_words = priv;
 	struct diff_words_style *style = diff_words->style;
@@ -3184,8 +3184,9 @@ static int is_conflict_marker(const char *line, int marker_size, unsigned long l
 }
 
 static void checkdiff_consume_hunk(void *priv,
-				   long ob, long on, long nb, long nn,
+				   long ob UNUSED, long on UNUSED,
-				   const char *func, long funclen)
+				   long nb, long nn UNUSED,
+				   const char *func UNUSED, long funclen UNUSED)
 
 {
 	struct checkdiff_t *data = priv;

range-diff.c

@@ -269,14 +269,18 @@ static void find_exact_matches(struct string_list *a, struct string_list *b)
 	hashmap_clear(&map);
 }
 
-static int diffsize_consume(void *data, char *line, unsigned long len)
+static int diffsize_consume(void *data,
+			     char *line UNUSED,
+			     unsigned long len UNUSED)
 {
 	(*(int *)data)++;
 	return 0;
 }
 
-static void diffsize_hunk(void *data, long ob, long on, long nb, long nn,
+static void diffsize_hunk(void *data,
-			  const char *funcline, long funclen)
+			  long ob UNUSED, long on UNUSED,
+			  long nb UNUSED, long nn UNUSED,
+			  const char *func UNUSED, long funclen UNUSED)
 {
 	diffsize_consume(data, NULL, 0);
 }
@@ -461,7 +465,7 @@ static void patch_diff(const char *a, const char *b,
 	diff_flush(diffopt);
 }
 
-static struct strbuf *output_prefix_cb(struct diff_options *opt, void *data)
+static struct strbuf *output_prefix_cb(struct diff_options *opt UNUSED, void *data)
 {
 	return data;
 }

revision.c

@@ -600,10 +600,12 @@ static struct commit *one_relevant_parent(const struct rev_info *revs,
 static int tree_difference = REV_TREE_SAME;
 
 static void file_add_remove(struct diff_options *options,
-		    int addremove, unsigned mode,
+		    int addremove,
-		    const struct object_id *oid,
+		    unsigned mode UNUSED,
-		    int oid_valid,
+		    const struct object_id *oid UNUSED,
-		    const char *fullpath, unsigned dirty_submodule)
+		    int oid_valid UNUSED,
+		    const char *fullpath UNUSED,
+		    unsigned dirty_submodule UNUSED)
 {
 	int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 	struct rev_info *revs = options->change_fn_data;
@@ -614,12 +616,15 @@ static void file_add_remove(struct diff_options *options,
 }
 
 static void file_change(struct diff_options *options,
-		 unsigned old_mode, unsigned new_mode,
+		 unsigned old_mode UNUSED,
-		 const struct object_id *old_oid,
+		 unsigned new_mode UNUSED,
-		 const struct object_id *new_oid,
+		 const struct object_id *old_oid UNUSED,
-		 int old_oid_valid, int new_oid_valid,
+		 const struct object_id *new_oid UNUSED,
-		 const char *fullpath,
+		 int old_oid_valid UNUSED,
-		 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
+		 int new_oid_valid UNUSED,
+		 const char *fullpath UNUSED,
+		 unsigned old_dirty_submodule UNUSED,
+		 unsigned new_dirty_submodule UNUSED)
 {
 	tree_difference = REV_TREE_DIFFERENT;
 	options->flags.has_changes = 1;

submodule.c

@@ -832,7 +832,7 @@ static void changed_submodule_data_clear(struct changed_submodule_data *cs_data)
 }
 
 static void collect_changed_submodules_cb(struct diff_queue_struct *q,
-					  struct diff_options *options,
+					  struct diff_options *options UNUSED,
 					  void *data)
 {
 	struct collect_changed_submodules_cb_data *me = data;

wt-status.c

@@ -438,7 +438,7 @@ static char short_submodule_status(struct wt_status_change_data *d)
 }
 
 static void wt_status_collect_changed_cb(struct diff_queue_struct *q,
-					 struct diff_options *options,
+					 struct diff_options *options UNUSED,
 					 void *data)
 {
 	struct wt_status *s = data;
@@ -525,7 +525,7 @@ static int unmerged_mask(struct index_state *istate, const char *path)
 }
 
 static void wt_status_collect_updated_cb(struct diff_queue_struct *q,
-					 struct diff_options *options,
+					 struct diff_options *options UNUSED,
 					 void *data)
 {
 	struct wt_status *s = data;