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#include "cache.h"
#include "tree-walk.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", &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 = strlen(a->path);
}
void update_tree_entry(struct tree_desc *desc)
{
void *buf = desc->buf;
unsigned long size = desc->size;
int len = strlen(buf) + 1 + 20;
if (size < len)
die("corrupt tree file");
desc->buf = buf + len;
desc->size = size - len;
}
const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
{
void *tree = desc->buf;
unsigned long size = desc->size;
int len = strlen(tree)+1;
const unsigned char *sha1 = tree + len;
const char *path = strchr(tree, ' ');
unsigned int mode;
if (!path || size < len + 20 || sscanf(tree, "%o", &mode) != 1)
die("corrupt tree file");
*pathp = path+1;
*modep = canon_mode(mode);
return sha1;
}
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 (;;) {
struct name_entry entry[3];
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);
}
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