[PATCH v3 4/9] ls-files: refactor away read_tree()

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Refactor away the read_tree() function into its only user,
overlay_tree_on_index().

First, change read_one_entry_opt() to use the strbuf parameter
read_tree_recursive() passes down in place. This finishes up a partial
refactoring started in 6a0b0b6de99 (tree.c: update read_tree_recursive
callback to pass strbuf as base, 2014-11-30).

Moving the rest into overlay_tree_on_index() makes this index juggling
we're doing easier to read.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/ls-files.c | 74 +++++++++++++++++++++-------------------------
 1 file changed, 33 insertions(+), 41 deletions(-)

diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 74d572a3e4a..db53e2c8e6d 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -423,7 +423,7 @@ static int get_common_prefix_len(const char *common_prefix)
 
 static int read_one_entry_opt(struct index_state *istate,
 			      const struct object_id *oid,
-			      const char *base, int baselen,
+			      struct strbuf *base,
 			      const char *pathname,
 			      unsigned mode, int stage, int opt)
 {
@@ -434,13 +434,13 @@ static int read_one_entry_opt(struct index_state *istate,
 		return READ_TREE_RECURSIVE;
 
 	len = strlen(pathname);
-	ce = make_empty_cache_entry(istate, baselen + len);
+	ce = make_empty_cache_entry(istate, base->len + len);
 
 	ce->ce_mode = create_ce_mode(mode);
 	ce->ce_flags = create_ce_flags(stage);
-	ce->ce_namelen = baselen + len;
-	memcpy(ce->name, base, baselen);
-	memcpy(ce->name + baselen, pathname, len+1);
+	ce->ce_namelen = base->len + len;
+	memcpy(ce->name, base->buf, base->len);
+	memcpy(ce->name + base->len, pathname, len+1);
 	oidcpy(&ce->oid, oid);
 	return add_index_entry(istate, ce, opt);
 }
@@ -450,7 +450,7 @@ static int read_one_entry(const struct object_id *oid, struct strbuf *base,
 			  void *context)
 {
 	struct index_state *istate = context;
-	return read_one_entry_opt(istate, oid, base->buf, base->len, pathname,
+	return read_one_entry_opt(istate, oid, base, pathname,
 				  mode, stage,
 				  ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
 }
@@ -464,44 +464,11 @@ static int read_one_entry_quick(const struct object_id *oid, struct strbuf *base
 				void *context)
 {
 	struct index_state *istate = context;
-	return read_one_entry_opt(istate, oid, base->buf, base->len, pathname,
+	return read_one_entry_opt(istate, oid, base, pathname,
 				  mode, stage,
 				  ADD_CACHE_JUST_APPEND);
 }
 
-
-static int read_tree(struct repository *r, struct tree *tree,
-		     struct pathspec *match, struct index_state *istate)
-{
-	read_tree_fn_t fn = NULL;
-	int i, err;
-
-
-	/*
-	 * See if we have cache entry at the stage.  If so,
-	 * do it the original slow way, otherwise, append and then
-	 * sort at the end.
-	 */
-	for (i = 0; !fn && i < istate->cache_nr; i++) {
-		const struct cache_entry *ce = istate->cache[i];
-		if (ce_stage(ce) == 1)
-			fn = read_one_entry;
-	}
-
-	if (!fn)
-		fn = read_one_entry_quick;
-	err = read_tree_recursive(r, tree, "", 0, 1, match, fn, istate);
-	if (fn == read_one_entry || err)
-		return err;
-
-	/*
-	 * Sort the cache entry -- we need to nuke the cache tree, though.
-	 */
-	cache_tree_free(&istate->cache_tree);
-	QSORT(istate->cache, istate->cache_nr, cmp_cache_name_compare);
-	return 0;
-}
-
 /*
  * Read the tree specified with --with-tree option
  * (typically, HEAD) into stage #1 and then
@@ -518,6 +485,8 @@ void overlay_tree_on_index(struct index_state *istate,
 	struct pathspec pathspec;
 	struct cache_entry *last_stage0 = NULL;
 	int i;
+	read_tree_fn_t fn = NULL;
+	int err;
 
 	if (get_oid(tree_name, &oid))
 		die("tree-ish %s not found.", tree_name);
@@ -540,9 +509,32 @@ void overlay_tree_on_index(struct index_state *istate,
 			       PATHSPEC_PREFER_CWD, prefix, matchbuf);
 	} else
 		memset(&pathspec, 0, sizeof(pathspec));
-	if (read_tree(the_repository, tree, &pathspec, istate))
+
+	/*
+	 * See if we have cache entry at the stage.  If so,
+	 * do it the original slow way, otherwise, append and then
+	 * sort at the end.
+	 */
+	for (i = 0; !fn && i < istate->cache_nr; i++) {
+		const struct cache_entry *ce = istate->cache[i];
+		if (ce_stage(ce) == 1)
+			fn = read_one_entry;
+	}
+
+	if (!fn)
+		fn = read_one_entry_quick;
+	err = read_tree_recursive(the_repository, tree, "", 0, 1, &pathspec, fn, istate);
+	if (err)
 		die("unable to read tree entries %s", tree_name);
 
+	/*
+	 * Sort the cache entry -- we need to nuke the cache tree, though.
+	 */
+	if (fn == read_one_entry_quick) {
+		cache_tree_free(&istate->cache_tree);
+		QSORT(istate->cache, istate->cache_nr, cmp_cache_name_compare);
+	}
+
 	for (i = 0; i < istate->cache_nr; i++) {
 		struct cache_entry *ce = istate->cache[i];
 		switch (ce_stage(ce)) {
-- 
2.31.0.rc2.211.g1d0b8788b3