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#include "cache.h"
struct relationship {
unsigned char sha1[20];
unsigned char parent[20];
};
static struct relationship **rels;
static int nr_rels, rel_allocs;
static int find_relationship(unsigned char *sha1, unsigned char *parent)
{
int first = 0, last = nr_rels;
while (first < last) {
int next = (first + last) / 2;
struct relationship *rel = rels[next];
int cmp;
cmp = memcmp(sha1, rel->sha1, 20);
if (!cmp) {
cmp = memcmp(parent, rel->parent, 20);
if (!cmp)
return next;
}
if (cmp < 0) {
last = next;
continue;
}
first = next+1;
}
return -first-1;
}
static int add_relationship(unsigned char *sha1, unsigned char *parent)
{
struct relationship *n;
int pos;
pos = find_relationship(sha1, parent);
if (pos >= 0)
return 0;
pos = -pos-1;
if (rel_allocs == nr_rels) {
rel_allocs = alloc_nr(rel_allocs);
rels = realloc(rels, rel_allocs * sizeof(struct relationship *));
}
n = malloc(sizeof(struct relationship));
memmove(rels + pos + 1, rels + pos, (nr_rels - pos) * sizeof(struct relationship *));
rels[pos] = n;
nr_rels++;
memcpy(n->sha1, sha1, 20);
memcpy(n->parent, parent, 20);
return 1;
}
static int already_seen(unsigned char *sha1)
{
static char null_sha[20];
int pos = find_relationship(sha1, null_sha);
if (pos < 0)
pos = -pos-1;
if (pos < nr_rels && !memcmp(sha1, rels[pos]->sha1, 20))
return 1;
return 0;
}
static int parse_commit(unsigned char *sha1)
{
if (!already_seen(sha1)) {
void *buffer;
unsigned long size;
char type[20];
unsigned char parent[20];
buffer = read_sha1_file(sha1, type, &size);
if (!buffer || strcmp(type, "commit"))
return -1;
buffer += 46; /* "tree " + "hex sha1" + "\n" */
while (!memcmp(buffer, "parent ", 7) && !get_sha1_hex(buffer+7, parent)) {
add_relationship(sha1, parent);
parse_commit(parent);
buffer += 48; /* "parent " + "hex sha1" + "\n" */
}
}
return 0;
}
static void read_cache_file(const char *path)
{
FILE *file = fopen(path, "r");
char line[100];
while (fgets(line, sizeof(line), file)) {
unsigned char sha1[20], parent[20];
if (get_sha1_hex(line, sha1) || get_sha1_hex(line + 41, parent))
usage("bad rev-tree cache file %s", path);
add_relationship(sha1, parent);
}
fclose(file);
}
/*
* Usage: rev-tree [--cache <cache-file>] <commit-id>
*
* The cache-file can be quite important for big trees. This is an
* expensive operation if you have to walk the whole chain of
* parents in a tree with a long revision history.
*/
int main(int argc, char **argv)
{
int i;
unsigned char sha1[20];
while (argc > 2) {
if (!strcmp(argv[1], "--cache")) {
read_cache_file(argv[2]);
argv += 2;
argc -= 2;
continue;
}
usage("unknown option %s", argv[1]);
}
if (argc != 2 || get_sha1_hex(argv[1], sha1))
usage("rev-tree [--cache <cache-file>] <commit-id>");
parse_commit(sha1);
for (i = 0; i < nr_rels; i++) {
char parent[60];
struct relationship *rel = rels[i];
strcpy(parent, sha1_to_hex(rel->parent));
printf("%s %s\n", sha1_to_hex(rel->sha1), parent);
}
return 0;
}
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