git/tree.c
Nicolas Pitre bd2c39f58f [PATCH] don't load and decompress objects twice with parse_object()
It turns out that parse_object() is loading and decompressing given
object to free it just before calling the specific object parsing
function which does mmap and decompress the same object again. This
patch introduces the ability to parse specific objects directly from a
memory buffer.

Without this patch, running git-fsck-cache on the kernel repositorytake:

	real    0m13.006s
	user    0m11.421s
	sys     0m1.218s

With this patch applied:

	real    0m8.060s
	user    0m7.071s
	sys     0m0.710s

The performance increase is significant, and this is kind of a
prerequisite for sane delta object support with fsck.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-06 11:02:01 -07:00

160 lines
3.8 KiB
C

#include "tree.h"
#include "blob.h"
#include "cache.h"
#include <stdlib.h>
const char *tree_type = "tree";
static int read_one_entry(unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
{
int len = strlen(pathname);
unsigned int size = cache_entry_size(baselen + len);
struct cache_entry *ce = xmalloc(size);
memset(ce, 0, size);
ce->ce_mode = create_ce_mode(mode);
ce->ce_flags = create_ce_flags(baselen + len, stage);
memcpy(ce->name, base, baselen);
memcpy(ce->name + baselen, pathname, len+1);
memcpy(ce->sha1, sha1, 20);
return add_cache_entry(ce, 1);
}
static int read_tree_recursive(void *buffer, unsigned long size,
const char *base, int baselen, int stage)
{
while (size) {
int len = strlen(buffer)+1;
unsigned char *sha1 = buffer + len;
char *path = strchr(buffer, ' ')+1;
unsigned int mode;
if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
return -1;
buffer = sha1 + 20;
size -= len + 20;
if (S_ISDIR(mode)) {
int retval;
int pathlen = strlen(path);
char *newbase = xmalloc(baselen + 1 + pathlen);
void *eltbuf;
char elttype[20];
unsigned long eltsize;
eltbuf = read_sha1_file(sha1, elttype, &eltsize);
if (!eltbuf || strcmp(elttype, "tree"))
return -1;
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, path, pathlen);
newbase[baselen + pathlen] = '/';
retval = read_tree_recursive(eltbuf, eltsize,
newbase,
baselen + pathlen + 1, stage);
free(eltbuf);
free(newbase);
if (retval)
return -1;
continue;
}
if (read_one_entry(sha1, base, baselen, path, mode, stage) < 0)
return -1;
}
return 0;
}
int read_tree(void *buffer, unsigned long size, int stage)
{
return read_tree_recursive(buffer, size, "", 0, stage);
}
struct tree *lookup_tree(unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj) {
struct tree *ret = xmalloc(sizeof(struct tree));
memset(ret, 0, sizeof(struct tree));
created_object(sha1, &ret->object);
ret->object.type = tree_type;
return ret;
}
if (obj->type != tree_type) {
error("Object %s is a %s, not a tree",
sha1_to_hex(sha1), obj->type);
return NULL;
}
return (struct tree *) obj;
}
int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
{
void *bufptr = buffer;
struct tree_entry_list **list_p;
if (item->object.parsed)
return 0;
item->object.parsed = 1;
list_p = &item->entries;
while (size) {
struct object *obj;
struct tree_entry_list *entry;
int len = 1+strlen(bufptr);
unsigned char *file_sha1 = bufptr + len;
char *path = strchr(bufptr, ' ');
unsigned int mode;
if (size < len + 20 || !path ||
sscanf(bufptr, "%o", &mode) != 1)
return -1;
entry = xmalloc(sizeof(struct tree_entry_list));
entry->name = strdup(path + 1);
entry->directory = S_ISDIR(mode) != 0;
entry->executable = (mode & S_IXUSR) != 0;
entry->symlink = S_ISLNK(mode) != 0;
entry->mode = mode;
entry->next = NULL;
bufptr += len + 20;
size -= len + 20;
if (entry->directory) {
entry->item.tree = lookup_tree(file_sha1);
obj = &entry->item.tree->object;
} else {
entry->item.blob = lookup_blob(file_sha1);
obj = &entry->item.blob->object;
}
if (obj)
add_ref(&item->object, obj);
*list_p = entry;
list_p = &entry->next;
}
return 0;
}
int parse_tree(struct tree *item)
{
char type[20];
void *buffer;
unsigned long size;
int ret;
if (item->object.parsed)
return 0;
buffer = read_sha1_file(item->object.sha1, type, &size);
if (!buffer)
return error("Could not read %s",
sha1_to_hex(item->object.sha1));
if (strcmp(type, tree_type)) {
free(buffer);
return error("Object %s not a tree",
sha1_to_hex(item->object.sha1));
}
ret = parse_tree_buffer(item, buffer, size);
free(buffer);
return ret;
}