git/object.c

#include "object.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "cache.h"
#include "tag.h"
#include "delta.h"

struct object **objs;
int nr_objs;
static int obj_allocs;

static int find_object(unsigned char *sha1)
{
	int first = 0, last = nr_objs;

        while (first < last) {
                int next = (first + last) / 2;
                struct object *obj = objs[next];
                int cmp;

                cmp = memcmp(sha1, obj->sha1, 20);
                if (!cmp)
                        return next;
                if (cmp < 0) {
                        last = next;
                        continue;
                }
                first = next+1;
        }
        return -first-1;
}

struct object *lookup_object(unsigned char *sha1)
{
	int pos = find_object(sha1);
	if (pos >= 0)
		return objs[pos];
	return NULL;
}

void created_object(unsigned char *sha1, struct object *obj)
{
	int pos = find_object(sha1);

	obj->parsed = 0;
	memcpy(obj->sha1, sha1, 20);
	obj->type = NULL;
	obj->refs = NULL;
	obj->used = 0;

	if (pos >= 0)
		die("Inserting %s twice\n", sha1_to_hex(sha1));
	pos = -pos-1;

	if (obj_allocs == nr_objs) {
		obj_allocs = alloc_nr(obj_allocs);
		objs = xrealloc(objs, obj_allocs * sizeof(struct object *));
	}

	/* Insert it into the right place */
	memmove(objs + pos + 1, objs + pos, (nr_objs - pos) * 
		sizeof(struct object *));

	objs[pos] = obj;
	nr_objs++;
}

void add_ref(struct object *refer, struct object *target)
{
	struct object_list **pp = &refer->refs;
	struct object_list *p;
	
	while ((p = *pp) != NULL) {
		if (p->item == target)
			return;
		pp = &p->next;
	}

	target->used = 1;
	p = xmalloc(sizeof(*p));
	p->item = target;
	p->next = NULL;
	*pp = p;
}

void mark_reachable(struct object *obj, unsigned int mask)
{
	struct object_list *p = obj->refs;

	/* If we've been here already, don't bother */
	if (obj->flags & mask)
		return;
	obj->flags |= mask;
	while (p) {
		mark_reachable(p->item, mask);
		p = p->next;
	}
}

struct object *parse_object(unsigned char *sha1)
{
	unsigned long mapsize;
	void *map = map_sha1_file(sha1, &mapsize);
	if (map) {
		int is_delta;
		struct object *obj;
		char type[100];
		unsigned long size;
		void *buffer = unpack_sha1_file(map, mapsize, type, &size);
		munmap(map, mapsize);
		if (!buffer)
			return NULL;
		is_delta = !strcmp(type, "delta");
		if (!is_delta && check_sha1_signature(sha1, buffer, size, type) < 0)
			printf("sha1 mismatch %s\n", sha1_to_hex(sha1));
		if (is_delta) {
			struct delta *delta = lookup_delta(sha1);
			parse_delta_buffer(delta, buffer, size);
			obj = (struct object *) delta;
		} else if (!strcmp(type, "blob")) {
			struct blob *blob = lookup_blob(sha1);
			parse_blob_buffer(blob, buffer, size);
			obj = &blob->object;
		} else if (!strcmp(type, "tree")) {
			struct tree *tree = lookup_tree(sha1);
			parse_tree_buffer(tree, buffer, size);
			obj = &tree->object;
		} else if (!strcmp(type, "commit")) {
			struct commit *commit = lookup_commit(sha1);
			parse_commit_buffer(commit, buffer, size);
			obj = &commit->object;
		} else if (!strcmp(type, "tag")) {
			struct tag *tag = lookup_tag(sha1);
			parse_tag_buffer(tag, buffer, size);
			obj = &tag->object;
		} else {
			obj = NULL;
		}
		free(buffer);
		return obj;
	}
	return NULL;
}