*/
#include "cache.h"
-static int unpack(unsigned char *sha1)
+static int stage = 0;
+
+static int read_one_entry(unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode)
+{
+ int len = strlen(pathname);
+ unsigned int size = cache_entry_size(baselen + len);
+ struct cache_entry *ce = malloc(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(unsigned char *sha1, const char *base, int baselen)
{
void *buffer;
unsigned long size;
buffer = read_sha1_file(sha1, type, &size);
if (!buffer)
- usage("unable to read sha1 file");
+ return -1;
if (strcmp(type, "tree"))
- usage("expected a 'tree' node");
+ return -1;
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)
- usage("corrupt 'tree' file");
+ return -1;
+
buffer = sha1 + 20;
size -= len + 20;
- printf("%o %s (%s)\n", mode, path, sha1_to_hex(sha1));
+
+ if (S_ISDIR(mode)) {
+ int retval;
+ int pathlen = strlen(path);
+ char *newbase = malloc(baselen + 1 + pathlen);
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, path, pathlen);
+ newbase[baselen + pathlen] = '/';
+ retval = read_tree(sha1, newbase, baselen + pathlen + 1);
+ free(newbase);
+ if (retval)
+ return -1;
+ continue;
+ }
+ if (read_one_entry(sha1, base, baselen, path, mode) < 0)
+ return -1;
}
return 0;
}
+static int remove_lock = 0;
+
+static void remove_lock_file(void)
+{
+ if (remove_lock)
+ unlink(".git/index.lock");
+}
+
+static int same(struct cache_entry *a, struct cache_entry *b)
+{
+ return a->ce_mode == b->ce_mode &&
+ !memcmp(a->sha1, b->sha1, 20);
+}
+
+
+/*
+ * This removes all trivial merges that don't change the tree
+ * and collapses them to state 0.
+ *
+ * _Any_ other merge is left to user policy. That includes "both
+ * created the same file", and "both removed the same file" - which are
+ * trivial, but the user might still want to _note_ it.
+ */
+static struct cache_entry *merge_entries(struct cache_entry *a,
+ struct cache_entry *b,
+ struct cache_entry *c)
+{
+ int len = ce_namelen(a);
+
+ /*
+ * Are they all the same filename? We won't do
+ * any name merging
+ */
+ if (ce_namelen(b) != len ||
+ ce_namelen(c) != len ||
+ memcmp(a->name, b->name, len) ||
+ memcmp(a->name, c->name, len))
+ return NULL;
+
+ /*
+ * Ok, all three entries describe the same
+ * filename, but maybe the contents or file
+ * mode have changed?
+ *
+ * The trivial cases end up being the ones where two
+ * out of three files are the same:
+ * - both destinations the same, trivially take either
+ * - one of the destination versions hasn't changed,
+ * take the other.
+ *
+ * The "all entries exactly the same" case falls out as
+ * a special case of any of the "two same" cases.
+ *
+ * Here "a" is "original", and "b" and "c" are the two
+ * trees we are merging.
+ */
+ if (same(b,c))
+ return c;
+ if (same(a,b))
+ return c;
+ if (same(a,c))
+ return b;
+ return NULL;
+}
+
+static void trivially_merge_cache(struct cache_entry **src, int nr)
+{
+ struct cache_entry **dst = src;
+
+ while (nr) {
+ struct cache_entry *ce, *result;
+
+ ce = src[0];
+ if (nr > 2 && (result = merge_entries(ce, src[1], src[2])) != NULL) {
+ ce = result;
+ ce->ce_flags &= ~htons(CE_STAGEMASK);
+ src += 2;
+ nr -= 2;
+ active_nr -= 2;
+ }
+ *dst = ce;
+ src++;
+ dst++;
+ nr--;
+ }
+}
+
int main(int argc, char **argv)
{
- int fd;
+ int i, newfd;
unsigned char sha1[20];
- if (argc != 2)
- usage("read-tree <key>");
- if (get_sha1_hex(argv[1], sha1) < 0)
- usage("read-tree <key>");
- sha1_file_directory = getenv(DB_ENVIRONMENT);
- if (!sha1_file_directory)
- sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
- if (unpack(sha1) < 0)
- usage("unpack failed");
+ newfd = open(".git/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
+ if (newfd < 0)
+ die("unable to create new cachefile");
+ atexit(remove_lock_file);
+ remove_lock = 1;
+
+ for (i = 1; i < argc; i++) {
+ const char *arg = argv[i];
+
+ /* "-m" stands for "merge", meaning we start in stage 1 */
+ if (!strcmp(arg, "-m")) {
+ stage = 1;
+ continue;
+ }
+ if (get_sha1_hex(arg, sha1) < 0)
+ usage("read-tree [-m] <sha1>");
+ if (stage > 3)
+ usage("can't merge more than two trees");
+ if (read_tree(sha1, "", 0) < 0)
+ die("failed to unpack tree object %s", arg);
+ stage++;
+ }
+ if (stage == 4)
+ trivially_merge_cache(active_cache, active_nr);
+ if (write_cache(newfd, active_cache, active_nr) ||
+ rename(".git/index.lock", ".git/index"))
+ die("unable to write new index file");
+ remove_lock = 0;
return 0;
}
projects / git.git / blobdiff