Cleanup of unused symcache variable inside diff-lib.c

Commit c40641b, 'Optimize
symlink/directory detection' by Linus Torvalds, removed the 'char
*symcache' parameter to the has_symlink_leading_path() function.  This
made all variables currently named 'symcache' inside diff-lib.c
unnecessary.

This also let us throw away the 'struct oneway_unpack_data', and
instead directly use the 'struct rev_info *revs' member, which
was the only member left after removal of the 'symcache[] array'
member.  The 'struct oneway_unpack_data' was introduced by the
following commit:

  948dd34  "diff-files: careful when inspecting work tree items"

Impact: cleanup
        PATH_MAX bytes less memory stack usage in some cases

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff-lib.c

@@ -61,14 +61,12 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 	int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
 	unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 			      ? CE_MATCH_RACY_IS_DIRTY : 0);
-	char symcache[PATH_MAX];
 
 	diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 
 	if (diff_unmerged_stage < 0)
 		diff_unmerged_stage = 2;
 	entries = active_nr;
-	symcache[0] = '\0';
 	for (i = 0; i < entries; i++) {
 		struct stat st;
 		unsigned int oldmode, newmode;
@@ -198,11 +196,6 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
  * diff-index
  */
 
-struct oneway_unpack_data {
-	struct rev_info *revs;
-	char symcache[PATH_MAX];
-};
-
 /* A file entry went away or appeared */
 static void diff_index_show_file(struct rev_info *revs,
 				 const char *prefix,
@@ -216,8 +209,7 @@ static void diff_index_show_file(struct rev_info *revs,
 static int get_stat_data(struct cache_entry *ce,
 			 const unsigned char **sha1p,
 			 unsigned int *modep,
-			 int cached, int match_missing,
-			 struct oneway_unpack_data *cbdata)
+			 int cached, int match_missing)
 {
 	const unsigned char *sha1 = ce->sha1;
 	unsigned int mode = ce->ce_mode;
@@ -248,35 +240,33 @@ static int get_stat_data(struct cache_entry *ce,
 	return 0;
 }
 
-static void show_new_file(struct oneway_unpack_data *cbdata,
+static void show_new_file(struct rev_info *revs,
 			  struct cache_entry *new,
 			  int cached, int match_missing)
 {
 	const unsigned char *sha1;
 	unsigned int mode;
-	struct rev_info *revs = cbdata->revs;
 
 	/*
 	 * New file in the index: it might actually be different in
 	 * the working copy.
 	 */
-	if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0)
+	if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 		return;
 
 	diff_index_show_file(revs, "+", new, sha1, mode);
 }
 
-static int show_modified(struct oneway_unpack_data *cbdata,
+static int show_modified(struct rev_info *revs,
 			 struct cache_entry *old,
 			 struct cache_entry *new,
 			 int report_missing,
 			 int cached, int match_missing)
 {
 	unsigned int mode, oldmode;
 	const unsigned char *sha1;
-	struct rev_info *revs = cbdata->revs;
 
-	if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0) {
+	if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 		if (report_missing)
 			diff_index_show_file(revs, "-", old,
 					     old->sha1, old->ce_mode);
@@ -344,8 +334,7 @@ static void do_oneway_diff(struct unpack_trees_options *o,
 	struct cache_entry *idx,
 	struct cache_entry *tree)
 {
-	struct oneway_unpack_data *cbdata = o->unpack_data;
-	struct rev_info *revs = cbdata->revs;
+	struct rev_info *revs = o->unpack_data;
 	int match_missing, cached;
 
 	/*
@@ -368,7 +357,7 @@ static void do_oneway_diff(struct unpack_trees_options *o,
 	 * Something added to the tree?
 	 */
 	if (!tree) {
-		show_new_file(cbdata, idx, cached, match_missing);
+		show_new_file(revs, idx, cached, match_missing);
 		return;
 	}
 
@@ -381,7 +370,7 @@ static void do_oneway_diff(struct unpack_trees_options *o,
 	}
 
 	/* Show difference between old and new */
-	show_modified(cbdata, tree, idx, 1, cached, match_missing);
+	show_modified(revs, tree, idx, 1, cached, match_missing);
 }
 
 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
@@ -418,8 +407,7 @@ static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
 {
 	struct cache_entry *idx = src[0];
 	struct cache_entry *tree = src[1];
-	struct oneway_unpack_data *cbdata = o->unpack_data;
-	struct rev_info *revs = cbdata->revs;
+	struct rev_info *revs = o->unpack_data;
 
 	if (idx && ce_stage(idx))
 		skip_same_name(idx, o);
@@ -446,7 +434,6 @@ int run_diff_index(struct rev_info *revs, int cached)
 	const char *tree_name;
 	struct unpack_trees_options opts;
 	struct tree_desc t;
-	struct oneway_unpack_data unpack_cb;
 
 	mark_merge_entries();
 
@@ -456,14 +443,12 @@ int run_diff_index(struct rev_info *revs, int cached)
 	if (!tree)
 		return error("bad tree object %s", tree_name);
 
-	unpack_cb.revs = revs;
-	unpack_cb.symcache[0] = '\0';
 	memset(&opts, 0, sizeof(opts));
 	opts.head_idx = 1;
 	opts.index_only = cached;
 	opts.merge = 1;
 	opts.fn = oneway_diff;
-	opts.unpack_data = &unpack_cb;
+	opts.unpack_data = revs;
 	opts.src_index = &the_index;
 	opts.dst_index = NULL;
 
@@ -486,7 +471,6 @@ int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 	struct cache_entry *last = NULL;
 	struct unpack_trees_options opts;
 	struct tree_desc t;
-	struct oneway_unpack_data unpack_cb;
 
 	/*
 	 * This is used by git-blame to run diff-cache internally;
@@ -515,14 +499,12 @@ int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 	if (!tree)
 		die("bad tree object %s", sha1_to_hex(tree_sha1));
 
-	unpack_cb.revs = &revs;
-	unpack_cb.symcache[0] = '\0';
 	memset(&opts, 0, sizeof(opts));
 	opts.head_idx = 1;
 	opts.index_only = 1;
 	opts.merge = 1;
 	opts.fn = oneway_diff;
-	opts.unpack_data = &unpack_cb;
+	opts.unpack_data = &revs;
 	opts.src_index = &the_index;
 	opts.dst_index = &the_index;