Merge branch 'mh/reflife'

Define memory ownership and lifetime rules for what for-each-ref
feeds to its callbacks (in short, "you do not own it, so make a
copy if you want to keep it").

* mh/reflife: (25 commits)
  refs: document the lifetime of the args passed to each_ref_fn
  register_ref(): make a copy of the bad reference SHA-1
  exclude_existing(): set existing_refs.strdup_strings
  string_list_add_refs_by_glob(): add a comment about memory management
  string_list_add_one_ref(): rename first parameter to "refname"
  show_head_ref(): rename first parameter to "refname"
  show_head_ref(): do not shadow name of argument
  add_existing(): do not retain a reference to sha1
  do_fetch(): clean up existing_refs before exiting
  do_fetch(): reduce scope of peer_item
  object_array_entry: fix memory handling of the name field
  find_first_merges(): remove unnecessary code
  find_first_merges(): initialize merges variable using initializer
  fsck: don't put a void*-shaped peg in a char*-shaped hole
  object_array_remove_duplicates(): rewrite to reduce copying
  revision: use object_array_filter() in implementation of gc_boundary()
  object_array: add function object_array_filter()
  revision: split some overly-long lines
  cmd_diff(): make it obvious which cases are exclusive of each other
  cmd_diff(): rename local variable "list" -> "entry"
  ...

1 files changed, 58 insertions, 12 deletions

diff --git a/object.c b/object.c
index 88d0bece81..cbc7333a7e 100644
--- a/object.c
+++ b/object.c
@@ -270,11 +270,18 @@ void add_object_array(struct object *obj, const char *name, struct object_array
 	add_object_array_with_mode(obj, name, array, S_IFINVALID);
 }
 
+/*
+ * A zero-length string to which object_array_entry::name can be
+ * initialized without requiring a malloc/free.
+ */
+static char object_array_slopbuf[1];
+
 void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode)
 {
 	unsigned nr = array->nr;
 	unsigned alloc = array->alloc;
 	struct object_array_entry *objects = array->objects;
+	struct object_array_entry *entry;
 
 	if (nr >= alloc) {
 		alloc = (alloc + 32) * 2;
@@ -282,28 +289,67 @@ void add_object_array_with_mode(struct object *obj, const char *name, struct obj
 		array->alloc = alloc;
 		array->objects = objects;
 	}
-	objects[nr].item = obj;
-	objects[nr].name = name;
-	objects[nr].mode = mode;
+	entry = &objects[nr];
+	entry->item = obj;
+	if (!name)
+		entry->name = NULL;
+	else if (!*name)
+		/* Use our own empty string instead of allocating one: */
+		entry->name = object_array_slopbuf;
+	else
+		entry->name = xstrdup(name);
+	entry->mode = mode;
 	array->nr = ++nr;
 }
 
-void object_array_remove_duplicates(struct object_array *array)
+void object_array_filter(struct object_array *array,
+			 object_array_each_func_t want, void *cb_data)
 {
-	unsigned int ref, src, dst;
+	unsigned nr = array->nr, src, dst;
 	struct object_array_entry *objects = array->objects;
 
-	for (ref = 0; ref + 1 < array->nr; ref++) {
-		for (src = ref + 1, dst = src;
-		     src < array->nr;
-		     src++) {
-			if (!strcmp(objects[ref].name, objects[src].name))
-				continue;
+	for (src = dst = 0; src < nr; src++) {
+		if (want(&objects[src], cb_data)) {
 			if (src != dst)
 				objects[dst] = objects[src];
 			dst++;
+		} else {
+			if (objects[src].name != object_array_slopbuf)
+				free(objects[src].name);
+		}
+	}
+	array->nr = dst;
+}
+
+/*
+ * Return true iff array already contains an entry with name.
+ */
+static int contains_name(struct object_array *array, const char *name)
+{
+	unsigned nr = array->nr, i;
+	struct object_array_entry *object = array->objects;
+
+	for (i = 0; i < nr; i++, object++)
+		if (!strcmp(object->name, name))
+			return 1;
+	return 0;
+}
+
+void object_array_remove_duplicates(struct object_array *array)
+{
+	unsigned nr = array->nr, src;
+	struct object_array_entry *objects = array->objects;
+
+	array->nr = 0;
+	for (src = 0; src < nr; src++) {
+		if (!contains_name(array, objects[src].name)) {
+			if (src != array->nr)
+				objects[array->nr] = objects[src];
+			array->nr++;
+		} else {
+			if (objects[src].name != object_array_slopbuf)
+				free(objects[src].name);
 		}
-		array->nr = dst;
 	}
 }