Nucleus

/*
 * This file implements the Directory Entry object and associated operations.
 */

#include <string.h>
#include <nucleus/object.h>
#include <nucleus/vfs.h>

/* Information for find callback */
struct FindData {
	const char *name;
	DirEntry *result;
};

static void direntry_delete(Object *);

/* Directory Entry object type */
ObjectType dirEntryType = {
	.size = sizeof(DirEntry),
	.delete = direntry_delete,
};

/* Hash a file name */
static uint32_t
name_hash(const char *name)
{
	uint32_t digest = 5381;
	int c;
	while (c = *name++)
		digest = ((digest << 5) + digest) ^ c;
	return digest;
}

/* Destroy a Directory Entry */
static void
direntry_delete(Object *obj)
{
	DirEntry *entry = (void *) obj;
	if (entry->inode)
		put(entry->inode);
}

/* Callback for finding a directory entry by name */
static int
compare_direntry_name(void *addr, void *data)
{
	DirEntry *entry = (void *) addr;
	struct FindData *find = data;
	uint32_t hash = name_hash(find->name);
	if (entry->hash != hash)
		return 0;
	if (strcmp(entry->name, find->name))
		return 0;
	find->result = get(entry);
	return 1;
}

/* Find a Directory Entry by name in a list */
DirEntry *
find_direntry(ObjectList *list, const char *name)
{
	lock(list);
	struct FindData data = {
		.name = name,
		.result = NULL,
	};
	iterate(list, compare_direntry_name, &data);
	unlock(list);
	return data.result;
}