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Revision 7d944c3399c4145293d599e1ddc76d1ac0c1e118 authored by Sam Vilain on 19 December 2009, 11:55:13 UTC, committed by Eric Wong on 21 December 2009, 10:32:48 UTC 
git-svn: memoize conversion of SVN merge ticket info to git commit ranges
 
Each time the svn mergeinfo ticket changes, we look it up in the rev_map;
when there are a lot of merged branches, this will result in many repeated
lookups of the same information for subsequent commits.  Arrange the slow
part of the function so that it may be memoized, and memoize it.  The more
expensive revision walking operation can be memoized separately.

[ew: changed "next" to "return" for function exit]

Signed-off-by: Sam Vilain <sam@vilain.net>
Acked-by: Eric Wong <normalperson@yhbt.net>
1 parent 1d144aa
Raw File
tag.c 
#include "cache.h"
#include "tag.h"
#include "commit.h"
#include "tree.h"
#include "blob.h"

const char *tag_type = "tag";

struct object *deref_tag(struct object *o, const char *warn, int warnlen)
{
	while (o && o->type == OBJ_TAG)
		if (((struct tag *)o)->tagged)
			o = parse_object(((struct tag *)o)->tagged->sha1);
		else
			o = NULL;
	if (!o && warn) {
		if (!warnlen)
			warnlen = strlen(warn);
		error("missing object referenced by '%.*s'", warnlen, warn);
	}
	return o;
}

struct tag *lookup_tag(const unsigned char *sha1)
{
	struct object *obj = lookup_object(sha1);
	if (!obj)
		return create_object(sha1, OBJ_TAG, alloc_tag_node());
	if (!obj->type)
		obj->type = OBJ_TAG;
        if (obj->type != OBJ_TAG) {
                error("Object %s is a %s, not a tag",
                      sha1_to_hex(sha1), typename(obj->type));
                return NULL;
        }
        return (struct tag *) obj;
}

int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
{
	int typelen, taglen;
	unsigned char sha1[20];
	const char *type_line, *tag_line, *sig_line;
	char type[20];
	const char *start = data;

        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;

	if (size < 64)
		return -1;
	if (memcmp("object ", data, 7) || get_sha1_hex((char *) data + 7, sha1))
		return -1;

	type_line = (char *) data + 48;
	if (memcmp("\ntype ", type_line-1, 6))
		return -1;

	tag_line = memchr(type_line, '\n', size - (type_line - start));
	if (!tag_line || memcmp("tag ", ++tag_line, 4))
		return -1;

	sig_line = memchr(tag_line, '\n', size - (tag_line - start));
	if (!sig_line)
		return -1;
	sig_line++;

	typelen = tag_line - type_line - strlen("type \n");
	if (typelen >= 20)
		return -1;
	memcpy(type, type_line + 5, typelen);
	type[typelen] = '\0';
	taglen = sig_line - tag_line - strlen("tag \n");
	item->tag = xmemdupz(tag_line + 4, taglen);

	if (!strcmp(type, blob_type)) {
		item->tagged = &lookup_blob(sha1)->object;
	} else if (!strcmp(type, tree_type)) {
		item->tagged = &lookup_tree(sha1)->object;
	} else if (!strcmp(type, commit_type)) {
		item->tagged = &lookup_commit(sha1)->object;
	} else if (!strcmp(type, tag_type)) {
		item->tagged = &lookup_tag(sha1)->object;
	} else {
		error("Unknown type %s", type);
		item->tagged = NULL;
	}

	return 0;
}

int parse_tag(struct tag *item)
{
	enum object_type type;
	void *data;
	unsigned long size;
	int ret;

	if (item->object.parsed)
		return 0;
	data = read_sha1_file(item->object.sha1, &type, &size);
	if (!data)
		return error("Could not read %s",
			     sha1_to_hex(item->object.sha1));
	if (type != OBJ_TAG) {
		free(data);
		return error("Object %s not a tag",
			     sha1_to_hex(item->object.sha1));
	}
	ret = parse_tag_buffer(item, data, size);
	free(data);
	return ret;
}
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