X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=read-tree.c;h=59e6950a4c0e38f41274d95ab9d8cdbf6b540b43;hb=aee461985f52857fa04999b2a988986dd8c84aba;hp=5784802e945e43612cbc5415681e9e08dc1cf1df;hpb=121481abf8d752ef871821d4ab9a3747595d86ae;p=git.git

diff --git a/read-tree.c b/read-tree.c
index 5784802e..59e6950a 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -5,6 +5,8 @@
  */
 #include "cache.h"
 
+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);
@@ -13,8 +15,8 @@ static int read_one_entry(unsigned char *sha1, const char *base, int baselen, co
 
 	memset(ce, 0, size);
 
-	ce->st_mode = mode;
-	ce->namelen = baselen + len;
+	ce->ce_mode = htonl(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);
@@ -63,43 +65,89 @@ static int read_tree(unsigned char *sha1, const char *base, int baselen)
 	return 0;
 }
 
+static int remove_lock = 0;
+
+static void remove_lock_file(void)
+{
+	if (remove_lock)
+		unlink(".git/index.lock");
+}
+
+/*
+ * This removes all identical entries and collapses them to state 0.
+ *
+ * _Any_ other merge (even a trivial one, like both ) 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 int same_entry(struct cache_entry *a,
+			struct cache_entry *b,
+			struct cache_entry *c)
+{
+	int len = ce_namelen(a);
+	return	a->ce_mode == b->ce_mode &&
+		a->ce_mode == c->ce_mode &&
+		ce_namelen(b) == len &&
+		ce_namelen(c) == len &&
+		!memcmp(a->name, b->name, len) &&
+		!memcmp(a->name, c->name, len) &&
+		!memcmp(a->sha1, b->sha1, 20) &&
+		!memcmp(a->sha1, c->sha1, 20);
+}
+
+static void trivially_merge_cache(struct cache_entry **src, int nr)
+{
+	struct cache_entry **dst = src;
+
+	while (nr) {
+		struct cache_entry *ce;
+
+		ce = src[0];
+		if (nr > 2 && same_entry(ce, src[1], src[2])) {
+			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 i, newfd;
 	unsigned char sha1[20];
 
-	newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
+	newfd = open(".git/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
 	if (newfd < 0)
-		usage("unable to create new cachefile");
+		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" current directory cache */
+		/* "-m" stands for "merge", meaning we start in stage 1 */
 		if (!strcmp(arg, "-m")) {
-			if (active_cache) {
-				fprintf(stderr, "read-tree: cannot merge old cache on top of new\n");
-				goto out;
-			}
-			if (read_cache() < 0) {
-				fprintf(stderr, "read-tree: corrupt directory cache\n");
-				goto out;
-			}
+			stage = 1;
 			continue;
 		}
-		if (get_sha1_hex(arg, sha1) < 0) {
-			fprintf(stderr, "read-tree [-m] <sha1>\n");
-			goto out;
-		}
-		if (read_tree(sha1, "", 0) < 0) {
-			fprintf(stderr, "failed to unpack tree object %s\n", arg);
-			goto out;
-		}
+		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 (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
-		return 0;
-
-out:
-	unlink(".dircache/index.lock");
-	exit(1);
+	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;
 }