1 files changed, 249 insertions, 281 deletions

diff --git a/unpack-trees.c b/unpack-trees.c
index 3e448d8974..ee9be29374 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -7,270 +7,12 @@
 #include "progress.h"
 #include "refs.h"
 
-#define DBRT_DEBUG 1
-
-struct tree_entry_list {
-	struct tree_entry_list *next;
-	unsigned int mode;
-	const char *name;
-	const unsigned char *sha1;
-};
-
-static struct tree_entry_list *create_tree_entry_list(struct tree_desc *desc)
-{
-	struct name_entry one;
-	struct tree_entry_list *ret = NULL;
-	struct tree_entry_list **list_p = &ret;
-
-	while (tree_entry(desc, &one)) {
-		struct tree_entry_list *entry;
-
-		entry = xmalloc(sizeof(struct tree_entry_list));
-		entry->name = one.path;
-		entry->sha1 = one.sha1;
-		entry->mode = one.mode;
-		entry->next = NULL;
-
-		*list_p = entry;
-		list_p = &entry->next;
-	}
-	return ret;
-}
-
-static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
-{
-	int len1 = strlen(name1);
-	int len2 = strlen(name2);
-	int len = len1 < len2 ? len1 : len2;
-	int ret = memcmp(name1, name2, len);
-	unsigned char c1, c2;
-	if (ret)
-		return ret;
-	c1 = name1[len];
-	c2 = name2[len];
-	if (!c1 && dir1)
-		c1 = '/';
-	if (!c2 && dir2)
-		c2 = '/';
-	ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
-	if (c1 && c2 && !ret)
-		ret = len1 - len2;
-	return ret;
-}
-
 static inline void remove_entry(int remove)
 {
 	if (remove >= 0)
 		remove_cache_entry_at(remove);
 }
 
-static int unpack_trees_rec(struct tree_entry_list **posns, int len,
-			    const char *base, struct unpack_trees_options *o,
-			    struct tree_entry_list *df_conflict_list)
-{
-	int remove;
-	int baselen = strlen(base);
-	int src_size = len + 1;
-	int retval = 0;
-
-	do {
-		int i;
-		const char *first;
-		int firstdir = 0;
-		int pathlen;
-		unsigned ce_size;
-		struct tree_entry_list **subposns;
-		struct cache_entry **src;
-		int any_files = 0;
-		int any_dirs = 0;
-		char *cache_name;
-		int ce_stage;
-		int skip_entry = 0;
-
-		/* Find the first name in the input. */
-
-		first = NULL;
-		cache_name = NULL;
-
-		/* Check the cache */
-		if (o->merge && o->pos < active_nr) {
-			/* This is a bit tricky: */
-			/* If the index has a subdirectory (with
-			 * contents) as the first name, it'll get a
-			 * filename like "foo/bar". But that's after
-			 * "foo", so the entry in trees will get
-			 * handled first, at which point we'll go into
-			 * "foo", and deal with "bar" from the index,
-			 * because the base will be "foo/". The only
-			 * way we can actually have "foo/bar" first of
-			 * all the things is if the trees don't
-			 * contain "foo" at all, in which case we'll
-			 * handle "foo/bar" without going into the
-			 * directory, but that's fine (and will return
-			 * an error anyway, with the added unknown
-			 * file case.
-			 */
-
-			cache_name = active_cache[o->pos]->name;
-			if (strlen(cache_name) > baselen &&
-			    !memcmp(cache_name, base, baselen)) {
-				cache_name += baselen;
-				first = cache_name;
-			} else {
-				cache_name = NULL;
-			}
-		}
-
-#if DBRT_DEBUG > 1
-		if (first)
-			fprintf(stderr, "index %s\n", first);
-#endif
-		for (i = 0; i < len; i++) {
-			if (!posns[i] || posns[i] == df_conflict_list)
-				continue;
-#if DBRT_DEBUG > 1
-			fprintf(stderr, "%d %s\n", i + 1, posns[i]->name);
-#endif
-			if (!first || entcmp(first, firstdir,
-					     posns[i]->name,
-					     S_ISDIR(posns[i]->mode)) > 0) {
-				first = posns[i]->name;
-				firstdir = S_ISDIR(posns[i]->mode);
-			}
-		}
-		/* No name means we're done */
-		if (!first)
-			goto leave_directory;
-
-		pathlen = strlen(first);
-		ce_size = cache_entry_size(baselen + pathlen);
-
-		src = xcalloc(src_size, sizeof(struct cache_entry *));
-
-		subposns = xcalloc(len, sizeof(struct tree_list_entry *));
-
-		remove = -1;
-		if (cache_name && !strcmp(cache_name, first)) {
-			any_files = 1;
-			src[0] = active_cache[o->pos];
-			remove = o->pos;
-			if (o->skip_unmerged && ce_stage(src[0]))
-				skip_entry = 1;
-		}
-
-		for (i = 0; i < len; i++) {
-			struct cache_entry *ce;
-
-			if (!posns[i] ||
-			    (posns[i] != df_conflict_list &&
-			     strcmp(first, posns[i]->name))) {
-				continue;
-			}
-
-			if (posns[i] == df_conflict_list) {
-				src[i + o->merge] = o->df_conflict_entry;
-				continue;
-			}
-
-			if (S_ISDIR(posns[i]->mode)) {
-				struct tree *tree = lookup_tree(posns[i]->sha1);
-				struct tree_desc t;
-				any_dirs = 1;
-				parse_tree(tree);
-				init_tree_desc(&t, tree->buffer, tree->size);
-				subposns[i] = create_tree_entry_list(&t);
-				posns[i] = posns[i]->next;
-				src[i + o->merge] = o->df_conflict_entry;
-				continue;
-			}
-
-			if (skip_entry) {
-				subposns[i] = df_conflict_list;
-				posns[i] = posns[i]->next;
-				continue;
-			}
-
-			if (!o->merge)
-				ce_stage = 0;
-			else if (i + 1 < o->head_idx)
-				ce_stage = 1;
-			else if (i + 1 > o->head_idx)
-				ce_stage = 3;
-			else
-				ce_stage = 2;
-
-			ce = xcalloc(1, ce_size);
-			ce->ce_mode = create_ce_mode(posns[i]->mode);
-			ce->ce_flags = create_ce_flags(baselen + pathlen,
-						       ce_stage);
-			memcpy(ce->name, base, baselen);
-			memcpy(ce->name + baselen, first, pathlen + 1);
-
-			any_files = 1;
-
-			hashcpy(ce->sha1, posns[i]->sha1);
-			src[i + o->merge] = ce;
-			subposns[i] = df_conflict_list;
-			posns[i] = posns[i]->next;
-		}
-		if (any_files) {
-			if (skip_entry) {
-				o->pos++;
-				while (o->pos < active_nr &&
-				       !strcmp(active_cache[o->pos]->name,
-					       src[0]->name))
-					o->pos++;
-			} else if (o->merge) {
-				int ret;
-
-#if DBRT_DEBUG > 1
-				fprintf(stderr, "%s:\n", first);
-				for (i = 0; i < src_size; i++) {
-					fprintf(stderr, " %d ", i);
-					if (src[i])
-						fprintf(stderr, "%06x %s\n", src[i]->ce_mode, sha1_to_hex(src[i]->sha1));
-					else
-						fprintf(stderr, "\n");
-				}
-#endif
-				ret = o->fn(src, o, remove);
-				if (ret < 0)
-					return ret;
-
-#if DBRT_DEBUG > 1
-				fprintf(stderr, "Added %d entries\n", ret);
-#endif
-				o->pos += ret;
-			} else {
-				remove_entry(remove);
-				for (i = 0; i < src_size; i++) {
-					if (src[i]) {
-						add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
-					}
-				}
-			}
-		}
-		if (any_dirs) {
-			char *newbase = xmalloc(baselen + 2 + pathlen);
-			memcpy(newbase, base, baselen);
-			memcpy(newbase + baselen, first, pathlen);
-			newbase[baselen + pathlen] = '/';
-			newbase[baselen + pathlen + 1] = '\0';
-			if (unpack_trees_rec(subposns, len, newbase, o,
-					     df_conflict_list)) {
-				retval = -1;
-				goto leave_directory;
-			}
-			free(newbase);
-		}
-		free(subposns);
-		free(src);
-	} while (1);
-
- leave_directory:
-	return retval;
-}
-
 /* Unlink the last component and attempt to remove leading
  * directories, in case this unlink is the removal of the
  * last entry in the directory -- empty directories are removed.
@@ -346,15 +88,241 @@ static void check_updates(struct unpack_trees_options *o)
 	stop_progress(&progress);
 }
 
-int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
+static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_options *o, int remove)
+{
+	int ret = o->fn(src, o, remove);
+	if (ret > 0) {
+		o->pos += ret;
+		ret = 0;
+	}
+	return ret;
+}
+
+static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+	struct cache_entry *src[5] = { ce, };
+	if (ce_stage(ce)) {
+		if (o->skip_unmerged) {
+			o->pos++;
+		} else {
+			remove_entry(o->pos);
+		}
+		return 0;
+	}
+	return call_unpack_fn(src, o, o->pos);
+}
+
+int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
+{
+	int i;
+	struct tree_desc t[3];
+	struct traverse_info newinfo;
+	struct name_entry *p;
+
+	p = names;
+	while (!p->mode)
+		p++;
+
+	newinfo = *info;
+	newinfo.prev = info;
+	newinfo.name = *p;
+	newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
+	newinfo.conflicts |= df_conflicts;
+
+	for (i = 0; i < n; i++, dirmask >>= 1) {
+		const unsigned char *sha1 = NULL;
+		if (dirmask & 1)
+			sha1 = names[i].sha1;
+		fill_tree_descriptor(t+i, sha1);
+	}
+	traverse_trees(n, t, &newinfo);
+	return 0;
+}
+
+/*
+ * Compare the traverse-path to the cache entry without actually
+ * having to generate the textual representation of the traverse
+ * path.
+ *
+ * NOTE! This *only* compares up to the size of the traverse path
+ * itself - the caller needs to do the final check for the cache
+ * entry having more data at the end!
+ */
+static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
+{
+	int len, pathlen, ce_len;
+	const char *ce_name;
+
+	if (info->prev) {
+		int cmp = do_compare_entry(ce, info->prev, &info->name);
+		if (cmp)
+			return cmp;
+	}
+	pathlen = info->pathlen;
+	ce_len = ce_namelen(ce);
+
+	/* If ce_len < pathlen then we must have previously hit "name == directory" entry */
+	if (ce_len < pathlen)
+		return -1;
+
+	ce_len -= pathlen;
+	ce_name = ce->name + pathlen;
+
+	len = tree_entry_len(n->path, n->sha1);
+	return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
+}
+
+static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
+{
+	int cmp = do_compare_entry(ce, info, n);
+	if (cmp)
+		return cmp;
+
+	/*
+	 * Even if the beginning compared identically, the ce should
+	 * compare as bigger than a directory leading up to it!
+	 */
+	return ce_namelen(ce) > traverse_path_len(info, n);
+}
+
+static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
+{
+	int len = traverse_path_len(info, n);
+	struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
+
+	ce->ce_mode = create_ce_mode(n->mode);
+	ce->ce_flags = create_ce_flags(len, stage);
+	hashcpy(ce->sha1, n->sha1);
+	make_traverse_path(ce->name, info, n);
+
+	return ce;
+}
+
+static int unpack_nondirectories(int n, unsigned long mask, unsigned long dirmask, struct cache_entry *src[5],
+	const struct name_entry *names, const struct traverse_info *info, int remove)
 {
-	struct tree_entry_list **posns;
 	int i;
-	struct tree_entry_list df_conflict_list;
+	struct unpack_trees_options *o = info->data;
+	unsigned long conflicts;
+
+	/* Do we have *only* directories? Nothing to do */
+	if (mask == dirmask && !src[0])
+		return 0;
+
+	conflicts = info->conflicts;
+	if (o->merge)
+		conflicts >>= 1;
+	conflicts |= dirmask;
+
+	/*
+	 * Ok, we've filled in up to any potential index entry in src[0],
+	 * now do the rest.
+	 */
+	for (i = 0; i < n; i++) {
+		int stage;
+		unsigned int bit = 1ul << i;
+		if (conflicts & bit) {
+			src[i + o->merge] = o->df_conflict_entry;
+			continue;
+		}
+		if (!(mask & bit))
+			continue;
+		if (!o->merge)
+			stage = 0;
+		else if (i + 1 < o->head_idx)
+			stage = 1;
+		else if (i + 1 > o->head_idx)
+			stage = 3;
+		else
+			stage = 2;
+		src[i + o->merge] = create_ce_entry(info, names + i, stage);
+	}
+
+	if (o->merge)
+		return call_unpack_fn(src, o, remove);
+
+	n += o->merge;
+	remove_entry(remove);
+	for (i = 0; i < n; i++)
+		add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
+	return 0;
+}
+
+static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
+{
+	struct cache_entry *src[5] = { NULL, };
+	struct unpack_trees_options *o = info->data;
+	int remove = -1;
+	const struct name_entry *p = names;
+
+	/* Find first entry with a real name (we could use "mask" too) */
+	while (!p->mode)
+		p++;
+
+	/* Are we supposed to look at the index too? */
+	if (o->merge) {
+		while (o->pos < active_nr) {
+			struct cache_entry *ce = active_cache[o->pos];
+			int cmp = compare_entry(ce, info, p);
+			if (cmp < 0) {
+				if (unpack_index_entry(ce, o) < 0)
+					return -1;
+				continue;
+			}
+			if (!cmp) {
+				if (ce_stage(ce)) {
+					/*
+					 * If we skip unmerged index entries, we'll skip this
+					 * entry *and* the tree entries associated with it!
+					 */
+					if (o->skip_unmerged)
+						return mask;
+					remove_entry(o->pos);
+					continue;
+				}
+				src[0] = ce;
+				remove = o->pos;
+			}
+			break;
+		}
+	}
+
+	if (unpack_nondirectories(n, mask, dirmask, src, names, info, remove) < 0)
+		return -1;
+
+	/* Now handle any directories.. */
+	if (dirmask) {
+		unsigned long conflicts = mask & ~dirmask;
+		if (o->merge) {
+			conflicts <<= 1;
+			if (src[0])
+				conflicts |= 1;
+		}
+		traverse_trees_recursive(n, dirmask, conflicts, names, info);
+		return mask;
+	}
+
+	return mask;
+}
+
+static int unpack_failed(struct unpack_trees_options *o, const char *message)
+{
+	if (!o->gently) {
+		if (message)
+			return error(message);
+		return -1;
+	}
+	discard_cache();
+	read_cache();
+	return -1;
+}
+
+int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
+{
 	static struct cache_entry *dfc;
 
-	memset(&df_conflict_list, 0, sizeof(df_conflict_list));
-	df_conflict_list.next = &df_conflict_list;
+	if (len > 4)
+		die("unpack_trees takes at most four trees");
 	memset(&state, 0, sizeof(state));
 	state.base_dir = "";
 	state.force = 1;
@@ -368,29 +336,29 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 	o->df_conflict_entry = dfc;
 
 	if (len) {
-		posns = xmalloc(len * sizeof(struct tree_entry_list *));
-		for (i = 0; i < len; i++)
-			posns[i] = create_tree_entry_list(t+i);
-
-		if (unpack_trees_rec(posns, len, o->prefix ? o->prefix : "",
-				     o, &df_conflict_list)) {
-			if (o->gently) {
-				discard_cache();
-				read_cache();
-			}
-			return -1;
-		}
+		const char *prefix = o->prefix ? o->prefix : "";
+		struct traverse_info info;
+
+		setup_traverse_info(&info, prefix);
+		info.fn = unpack_callback;
+		info.data = o;
+
+		if (traverse_trees(len, t, &info) < 0)
+			return unpack_failed(o, NULL);
 	}
 
-	if (o->trivial_merges_only && o->nontrivial_merge) {
-		if (o->gently) {
-			discard_cache();
-			read_cache();
+	/* Any left-over entries in the index? */
+	if (o->merge) {
+		while (o->pos < active_nr) {
+			struct cache_entry *ce = active_cache[o->pos];
+			if (unpack_index_entry(ce, o) < 0)
+				return unpack_failed(o, NULL);
 		}
-		return o->gently ? -1 :
-			error("Merge requires file-level merging");
 	}
 
+	if (o->trivial_merges_only && o->nontrivial_merge)
+		return unpack_failed(o, "Merge requires file-level merging");
+
 	check_updates(o);
 	return 0;
 }