1 files changed, 164 insertions, 13 deletions

diff --git a/read-tree.c b/read-tree.c
index e16e91b173..a3ada55c15 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -9,6 +9,7 @@
 
 #include "object.h"
 #include "tree.h"
+#include "cache-tree.h"
 #include <sys/time.h>
 #include <signal.h>
 
@@ -21,6 +22,7 @@ static int trivial_merges_only = 0;
 static int aggressive = 0;
 static int verbose_update = 0;
 static volatile int progress_update = 0;
+static const char *prefix = NULL;
 
 static int head_idx = -1;
 static int merge_size = 0;
@@ -369,7 +371,8 @@ static int unpack_trees(merge_fn_t fn)
 			posns[i] = ((struct tree *) posn->item)->entries;
 			posn = posn->next;
 		}
-		if (unpack_trees_rec(posns, len, "", fn, &indpos))
+		if (unpack_trees_rec(posns, len, prefix ? prefix : "",
+				     fn, &indpos))
 			return -1;
 	}
 
@@ -408,7 +411,7 @@ static void verify_uptodate(struct cache_entry *ce)
 {
 	struct stat st;
 
-	if (index_only)
+	if (index_only || reset)
 		return;
 
 	if (!lstat(ce->name, &st)) {
@@ -426,6 +429,27 @@ static void verify_uptodate(struct cache_entry *ce)
 	die("Entry '%s' not uptodate. Cannot merge.", ce->name);
 }
 
+static void invalidate_ce_path(struct cache_entry *ce)
+{
+	if (ce)
+		cache_tree_invalidate_path(active_cache_tree, ce->name);
+}
+
+/*
+ * We do not want to remove or overwrite a working tree file that
+ * is not tracked.
+ */
+static void verify_absent(const char *path, const char *action)
+{
+	struct stat st;
+
+	if (index_only || reset || !update)
+		return;
+	if (!lstat(path, &st))
+		die("Untracked working tree file '%s' "
+		    "would be %s by merge.", path, action);
+}
+
 static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
 {
 	merge->ce_flags |= htons(CE_UPDATE);
@@ -441,8 +465,14 @@ static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
 			*merge = *old;
 		} else {
 			verify_uptodate(old);
+			invalidate_ce_path(old);
 		}
 	}
+	else {
+		verify_absent(merge->name, "overwritten");
+		invalidate_ce_path(merge);
+	}
+
 	merge->ce_flags &= ~htons(CE_STAGEMASK);
 	add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
 	return 1;
@@ -452,8 +482,11 @@ static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
 {
 	if (old)
 		verify_uptodate(old);
+	else
+		verify_absent(ce->name, "removed");
 	ce->ce_mode = 0;
 	add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
+	invalidate_ce_path(ce);
 	return 1;
 }
 
@@ -487,6 +520,7 @@ static int threeway_merge(struct cache_entry **stages)
 	int count;
 	int head_match = 0;
 	int remote_match = 0;
+	const char *path = NULL;
 
 	int df_conflict_head = 0;
 	int df_conflict_remote = 0;
@@ -498,8 +532,11 @@ static int threeway_merge(struct cache_entry **stages)
 	for (i = 1; i < head_idx; i++) {
 		if (!stages[i])
 			any_anc_missing = 1;
-		else
+		else {
+			if (!path)
+				path = stages[i]->name;
 			no_anc_exists = 0;
+		}
 	}
 
 	index = stages[0];
@@ -515,8 +552,15 @@ static int threeway_merge(struct cache_entry **stages)
 		remote = NULL;
 	}
 
+	if (!path && index)
+		path = index->name;
+	if (!path && head)
+		path = head->name;
+	if (!path && remote)
+		path = remote->name;
+
 	/* First, if there's a #16 situation, note that to prevent #13
-	 * and #14. 
+	 * and #14.
 	 */
 	if (!same(remote, head)) {
 		for (i = 1; i < head_idx; i++) {
@@ -575,6 +619,8 @@ static int threeway_merge(struct cache_entry **stages)
 		    (remote_deleted && head && head_match)) {
 			if (index)
 				return deleted_entry(index, index);
+			else if (path)
+				verify_absent(path, "removed");
 			return 0;
 		}
 		/*
@@ -592,6 +638,8 @@ static int threeway_merge(struct cache_entry **stages)
 	if (index) {
 		verify_uptodate(index);
 	}
+	else if (path)
+		verify_absent(path, "overwritten");
 
 	nontrivial_merge = 1;
 
@@ -674,6 +722,28 @@ static int twoway_merge(struct cache_entry **src)
 }
 
 /*
+ * Bind merge.
+ *
+ * Keep the index entries at stage0, collapse stage1 but make sure
+ * stage0 does not have anything there.
+ */
+static int bind_merge(struct cache_entry **src)
+{
+	struct cache_entry *old = src[0];
+	struct cache_entry *a = src[1];
+
+	if (merge_size != 1)
+		return error("Cannot do a bind merge of %d trees\n",
+			     merge_size);
+	if (a && old)
+		die("Entry '%s' overlaps.  Cannot bind.", a->name);
+	if (!a)
+		return keep_entry(old);
+	else
+		return merged_entry(a, NULL);
+}
+
+/*
  * One-way merge.
  *
  * The rule is:
@@ -688,8 +758,10 @@ static int oneway_merge(struct cache_entry **src)
 		return error("Cannot do a oneway merge of %d trees",
 			     merge_size);
 
-	if (!a)
-		return deleted_entry(old, NULL);
+	if (!a) {
+		invalidate_ce_path(old);
+		return deleted_entry(old, old);
+	}
 	if (old && same(old, a)) {
 		if (reset) {
 			struct stat st;
@@ -699,7 +771,7 @@ static int oneway_merge(struct cache_entry **src)
 		}
 		return keep_entry(old);
 	}
-	return merged_entry(a, NULL);
+	return merged_entry(a, old);
 }
 
 static int read_cache_unmerged(void)
@@ -714,6 +786,7 @@ static int read_cache_unmerged(void)
 		struct cache_entry *ce = active_cache[i];
 		if (ce_stage(ce)) {
 			deleted++;
+			invalidate_ce_path(ce);
 			continue;
 		}
 		if (deleted)
@@ -724,7 +797,40 @@ static int read_cache_unmerged(void)
 	return deleted;
 }
 
-static const char read_tree_usage[] = "git-read-tree (<sha> | -m [--aggressive] [-u | -i] <sha1> [<sha2> [<sha3>]])";
+static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
+{
+	struct tree_entry_list *ent;
+	int cnt;
+	
+	memcpy(it->sha1, tree->object.sha1, 20);
+	for (cnt = 0, ent = tree->entries; ent; ent = ent->next) {
+		if (!ent->directory)
+			cnt++;
+		else {
+			struct cache_tree_sub *sub;
+			struct tree *subtree = (struct tree *)ent->item.tree;
+			if (!subtree->object.parsed)
+				parse_tree(subtree);
+			sub = cache_tree_sub(it, ent->name);
+			sub->cache_tree = cache_tree();
+			prime_cache_tree_rec(sub->cache_tree, subtree);
+			cnt += sub->cache_tree->entry_count;
+		}
+	}
+	it->entry_count = cnt;
+}
+
+static void prime_cache_tree(void)
+{
+	struct tree *tree = (struct tree *)trees->item;
+	if (!tree)
+		return;
+	active_cache_tree = cache_tree();
+	prime_cache_tree_rec(active_cache_tree, tree);
+
+}
+
+static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] <sha1> [<sha2> [<sha3>]])";
 
 static struct cache_file cache_file;
 
@@ -769,9 +875,24 @@ int main(int argc, char **argv)
 			continue;
 		}
 
+		/* "--prefix=<subdirectory>/" means keep the current index
+		 *  entries and put the entries from the tree under the
+		 * given subdirectory.
+		 */
+		if (!strncmp(arg, "--prefix=", 9)) {
+			if (stage || merge || prefix)
+				usage(read_tree_usage);
+			prefix = arg + 9;
+			merge = 1;
+			stage = 1;
+			if (read_cache_unmerged())
+				die("you need to resolve your current index first");
+			continue;
+		}
+
 		/* This differs from "-m" in that we'll silently ignore unmerged entries */
 		if (!strcmp(arg, "--reset")) {
-			if (stage || merge)
+			if (stage || merge || prefix)
 				usage(read_tree_usage);
 			reset = 1;
 			merge = 1;
@@ -792,7 +913,7 @@ int main(int argc, char **argv)
 
 		/* "-m" stands for "merge", meaning we start in stage 1 */
 		if (!strcmp(arg, "-m")) {
-			if (stage || merge)
+			if (stage || merge || prefix)
 				usage(read_tree_usage);
 			if (read_cache_unmerged())
 				die("you need to resolve your current index first");
@@ -814,21 +935,39 @@ int main(int argc, char **argv)
 	if ((update||index_only) && !merge)
 		usage(read_tree_usage);
 
+	if (prefix) {
+		int pfxlen = strlen(prefix);
+		int pos;
+		if (prefix[pfxlen-1] != '/')
+			die("prefix must end with /");
+		if (stage != 2)
+			die("binding merge takes only one tree");
+		pos = cache_name_pos(prefix, pfxlen);
+		if (0 <= pos)
+			die("corrupt index file");
+		pos = -pos-1;
+		if (pos < active_nr &&
+		    !strncmp(active_cache[pos]->name, prefix, pfxlen))
+			die("subdirectory '%s' already exists.", prefix);
+		pos = cache_name_pos(prefix, pfxlen-1);
+		if (0 <= pos)
+			die("file '%.*s' already exists.", pfxlen-1, prefix);
+	}
+
 	if (merge) {
 		if (stage < 2)
 			die("just how do you expect me to merge %d trees?", stage-1);
 		switch (stage - 1) {
 		case 1:
-			fn = oneway_merge;
+			fn = prefix ? bind_merge : oneway_merge;
 			break;
 		case 2:
 			fn = twoway_merge;
 			break;
 		case 3:
-			fn = threeway_merge;
-			break;
 		default:
 			fn = threeway_merge;
+			cache_tree_free(&active_cache_tree);
 			break;
 		}
 
@@ -839,6 +978,18 @@ int main(int argc, char **argv)
 	}
 
 	unpack_trees(fn);
+
+	/*
+	 * When reading only one tree (either the most basic form,
+	 * "-m ent" or "--reset ent" form), we can obtain a fully
+	 * valid cache-tree because the index must match exactly
+	 * what came from the tree.
+	 */
+	if (trees && trees->item && (!merge || (stage == 2))) {
+		cache_tree_free(&active_cache_tree);
+		prime_cache_tree();
+	}
+
 	if (write_cache(newfd, active_cache, active_nr) ||
 	    commit_index_file(&cache_file))
 		die("unable to write new index file");