mirror of
https://github.com/git/git
synced 2024-08-25 02:35:46 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
This is a micro-optimization that grew out of the mailing list discussion about "strlen()" showing up in profiles. We used to pass regular C strings around to the low-level tree walking routines, and while this worked fine, it meant that we needed to call strlen() on strings that the caller always actually knew the size of anyway. So pass the length of the string down wih the string, and avoid unnecessary calls to strlen(). Also, when extracting a pathname from a tree entry, use "tree_entry_len()" instead of strlen(), since the length of the pathname is directly calculable from the decoded tree entry itself without having to actually do another strlen(). This shaves off another ~5-10% from some loads that are very tree intensive (notably doing commit filtering by a pathspec). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>" Signed-off-by: Junio C Hamano <junkio@cox.net>
219 lines
4.4 KiB
C
219 lines
4.4 KiB
C
#include "cache.h"
|
|
#include "tree-walk.h"
|
|
#include "tree.h"
|
|
|
|
void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
|
|
{
|
|
unsigned long size = 0;
|
|
void *buf = NULL;
|
|
|
|
if (sha1) {
|
|
buf = read_object_with_reference(sha1, tree_type, &size, NULL);
|
|
if (!buf)
|
|
die("unable to read tree %s", sha1_to_hex(sha1));
|
|
}
|
|
desc->size = size;
|
|
desc->buf = buf;
|
|
return buf;
|
|
}
|
|
|
|
static int entry_compare(struct name_entry *a, struct name_entry *b)
|
|
{
|
|
return base_name_compare(
|
|
a->path, a->pathlen, a->mode,
|
|
b->path, b->pathlen, b->mode);
|
|
}
|
|
|
|
static void entry_clear(struct name_entry *a)
|
|
{
|
|
memset(a, 0, sizeof(*a));
|
|
}
|
|
|
|
static void entry_extract(struct tree_desc *t, struct name_entry *a)
|
|
{
|
|
a->sha1 = tree_entry_extract(t, &a->path, &a->mode);
|
|
a->pathlen = tree_entry_len(a->path, a->sha1);
|
|
}
|
|
|
|
void update_tree_entry(struct tree_desc *desc)
|
|
{
|
|
const void *buf = desc->buf;
|
|
unsigned long size = desc->size;
|
|
int len = strlen(buf) + 1 + 20;
|
|
|
|
if (size < len)
|
|
die("corrupt tree file");
|
|
desc->buf = (char *) buf + len;
|
|
desc->size = size - len;
|
|
}
|
|
|
|
static const char *get_mode(const char *str, unsigned int *modep)
|
|
{
|
|
unsigned char c;
|
|
unsigned int mode = 0;
|
|
|
|
while ((c = *str++) != ' ') {
|
|
if (c < '0' || c > '7')
|
|
return NULL;
|
|
mode = (mode << 3) + (c - '0');
|
|
}
|
|
*modep = mode;
|
|
return str;
|
|
}
|
|
|
|
const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
|
|
{
|
|
const void *tree = desc->buf;
|
|
unsigned long size = desc->size;
|
|
int len = strlen(tree)+1;
|
|
const unsigned char *sha1 = (unsigned char *) tree + len;
|
|
const char *path;
|
|
unsigned int mode;
|
|
|
|
path = get_mode(tree, &mode);
|
|
if (!path || size < len + 20)
|
|
die("corrupt tree file");
|
|
*pathp = path;
|
|
*modep = canon_mode(mode);
|
|
return sha1;
|
|
}
|
|
|
|
int tree_entry(struct tree_desc *desc, struct name_entry *entry)
|
|
{
|
|
const void *tree = desc->buf;
|
|
const char *path;
|
|
unsigned long len, size = desc->size;
|
|
|
|
if (!size)
|
|
return 0;
|
|
|
|
path = get_mode(tree, &entry->mode);
|
|
if (!path)
|
|
die("corrupt tree file");
|
|
|
|
entry->path = path;
|
|
len = strlen(path);
|
|
entry->pathlen = len;
|
|
|
|
path += len + 1;
|
|
entry->sha1 = (const unsigned char *) path;
|
|
|
|
path += 20;
|
|
len = path - (char *) tree;
|
|
if (len > size)
|
|
die("corrupt tree file");
|
|
|
|
desc->buf = path;
|
|
desc->size = size - len;
|
|
return 1;
|
|
}
|
|
|
|
void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
|
|
{
|
|
struct name_entry *entry = xmalloc(n*sizeof(*entry));
|
|
|
|
for (;;) {
|
|
unsigned long mask = 0;
|
|
int i, last;
|
|
|
|
last = -1;
|
|
for (i = 0; i < n; i++) {
|
|
if (!t[i].size)
|
|
continue;
|
|
entry_extract(t+i, entry+i);
|
|
if (last >= 0) {
|
|
int cmp = entry_compare(entry+i, entry+last);
|
|
|
|
/*
|
|
* Is the new name bigger than the old one?
|
|
* Ignore it
|
|
*/
|
|
if (cmp > 0)
|
|
continue;
|
|
/*
|
|
* Is the new name smaller than the old one?
|
|
* Ignore all old ones
|
|
*/
|
|
if (cmp < 0)
|
|
mask = 0;
|
|
}
|
|
mask |= 1ul << i;
|
|
last = i;
|
|
}
|
|
if (!mask)
|
|
break;
|
|
|
|
/*
|
|
* Update the tree entries we've walked, and clear
|
|
* all the unused name-entries.
|
|
*/
|
|
for (i = 0; i < n; i++) {
|
|
if (mask & (1ul << i)) {
|
|
update_tree_entry(t+i);
|
|
continue;
|
|
}
|
|
entry_clear(entry + i);
|
|
}
|
|
callback(n, mask, entry, base);
|
|
}
|
|
free(entry);
|
|
}
|
|
|
|
static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
|
|
{
|
|
int namelen = strlen(name);
|
|
while (t->size) {
|
|
const char *entry;
|
|
const unsigned char *sha1;
|
|
int entrylen, cmp;
|
|
|
|
sha1 = tree_entry_extract(t, &entry, mode);
|
|
update_tree_entry(t);
|
|
entrylen = tree_entry_len(entry, sha1);
|
|
if (entrylen > namelen)
|
|
continue;
|
|
cmp = memcmp(name, entry, entrylen);
|
|
if (cmp > 0)
|
|
continue;
|
|
if (cmp < 0)
|
|
break;
|
|
if (entrylen == namelen) {
|
|
hashcpy(result, sha1);
|
|
return 0;
|
|
}
|
|
if (name[entrylen] != '/')
|
|
continue;
|
|
if (!S_ISDIR(*mode))
|
|
break;
|
|
if (++entrylen == namelen) {
|
|
hashcpy(result, sha1);
|
|
return 0;
|
|
}
|
|
return get_tree_entry(sha1, name + entrylen, result, mode);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
|
|
{
|
|
int retval;
|
|
void *tree;
|
|
struct tree_desc t;
|
|
unsigned char root[20];
|
|
|
|
tree = read_object_with_reference(tree_sha1, tree_type, &t.size, root);
|
|
if (!tree)
|
|
return -1;
|
|
|
|
if (name[0] == '\0') {
|
|
hashcpy(sha1, root);
|
|
return 0;
|
|
}
|
|
|
|
t.buf = tree;
|
|
retval = find_tree_entry(&t, name, sha1, mode);
|
|
free(tree);
|
|
return retval;
|
|
}
|
|
|