[PATCH 3/4] tree-walk: actually move tree_entry_interesting() to tree-walk.c

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This function can be potentially used in more places than just
tree-diff.c. This patches removes struct diff_options dependency from
the function, and moves it to tree-walk.c.

No functionality change intended.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 tree-diff.c |  121 ++---------------------------------------------------------
 tree-walk.c |   25 +++++-------
 tree-walk.h |    3 +
 3 files changed, 17 insertions(+), 132 deletions(-)

diff --git a/tree-diff.c b/tree-diff.c
index cd659c6..332f0c8 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -82,120 +82,6 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const
 	return 0;
 }
 
-/*
- * Is a tree entry interesting given the pathspec we have?
- *
- * Return:
- *  - 2 for "yes, and all subsequent entries will be"
- *  - 1 for yes
- *  - zero for no
- *  - negative for "no, and no subsequent entries will be either"
- */
-static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
-{
-	const char *path;
-	const unsigned char *sha1;
-	unsigned mode;
-	int i;
-	int pathlen;
-	int never_interesting = -1;
-
-	if (!opt->nr_paths)
-		return 1;
-
-	sha1 = tree_entry_extract(desc, &path, &mode);
-
-	pathlen = tree_entry_len(path, sha1);
-
-	for (i = 0; i < opt->nr_paths; i++) {
-		const char *match = opt->paths[i];
-		int matchlen = opt->pathlens[i];
-		int m = -1; /* signals that we haven't called strncmp() */
-
-		if (baselen >= matchlen) {
-			/* If it doesn't match, move along... */
-			if (strncmp(base, match, matchlen))
-				continue;
-
-			/*
-			 * If the base is a subdirectory of a path which
-			 * was specified, all of them are interesting.
-			 */
-			if (!matchlen ||
-			    base[matchlen] == '/' ||
-			    match[matchlen - 1] == '/')
-				return 2;
-
-			/* Just a random prefix match */
-			continue;
-		}
-
-		/* Does the base match? */
-		if (strncmp(base, match, baselen))
-			continue;
-
-		match += baselen;
-		matchlen -= baselen;
-
-		if (never_interesting) {
-			/*
-			 * We have not seen any match that sorts later
-			 * than the current path.
-			 */
-
-			/*
-			 * Does match sort strictly earlier than path
-			 * with their common parts?
-			 */
-			m = strncmp(match, path,
-				    (matchlen < pathlen) ? matchlen : pathlen);
-			if (m < 0)
-				continue;
-
-			/*
-			 * If we come here even once, that means there is at
-			 * least one pathspec that would sort equal to or
-			 * later than the path we are currently looking at.
-			 * In other words, if we have never reached this point
-			 * after iterating all pathspecs, it means all
-			 * pathspecs are either outside of base, or inside the
-			 * base but sorts strictly earlier than the current
-			 * one.  In either case, they will never match the
-			 * subsequent entries.  In such a case, we initialized
-			 * the variable to -1 and that is what will be
-			 * returned, allowing the caller to terminate early.
-			 */
-			never_interesting = 0;
-		}
-
-		if (pathlen > matchlen)
-			continue;
-
-		if (matchlen > pathlen) {
-			if (match[pathlen] != '/')
-				continue;
-			if (!S_ISDIR(mode))
-				continue;
-		}
-
-		if (m == -1)
-			/*
-			 * we cheated and did not do strncmp(), so we do
-			 * that here.
-			 */
-			m = strncmp(match, path, pathlen);
-
-		/*
-		 * If common part matched earlier then it is a hit,
-		 * because we rejected the case where path is not a
-		 * leading directory and is shorter than match.
-		 */
-		if (!m)
-			return 1;
-	}
-	return never_interesting; /* No matches */
-}
-
 /* A whole sub-tree went away or appeared */
 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
 {
@@ -206,8 +92,8 @@ static void show_tree(struct diff_options *opt, const char *prefix, struct tree_
 		if (all_interesting)
 			show = 1;
 		else {
-			show = tree_entry_interesting(desc, base, baselen,
-						      opt);
+			show = tree_entry_interesting(&desc->entry, base, baselen,
+						      opt->paths, opt->pathlens, opt->nr_paths);
 			if (show == 2)
 				all_interesting = 1;
 		}
@@ -266,7 +152,8 @@ static void skip_uninteresting(struct tree_desc *t, const char *base, int basele
 		if (all_interesting)
 			show = 1;
 		else {
-			show = tree_entry_interesting(t, base, baselen, opt);
+			show = tree_entry_interesting(&t->entry, base, baselen,
+						      opt->paths, opt->pathlens, opt->nr_paths);
 			if (show == 2)
 				all_interesting = 1;
 		}
diff --git a/tree-walk.c b/tree-walk.c
index bc83fa3..c665e35 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -2,7 +2,6 @@
 #include "tree-walk.h"
 #include "unpack-trees.h"
 #include "tree.h"
-#include "diff.h"
 
 static const char *get_mode(const char *str, unsigned int *modep)
 {
@@ -466,25 +465,21 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
  *  - zero for no
  *  - negative for "no, and no subsequent entries will be either"
  */
-static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
+int tree_entry_interesting(const struct name_entry *entry, const char *base, int baselen,
+			   const char **paths, int *pathlens, int nr_paths)
 {
-	const char *path;
-	const unsigned char *sha1;
-	unsigned mode;
 	int i;
 	int pathlen;
 	int never_interesting = -1;
 
-	if (!opt->nr_paths)
+	if (!nr_paths)
 		return 1;
 
-	sha1 = tree_entry_extract(desc, &path, &mode);
-
-	pathlen = tree_entry_len(path, sha1);
+	pathlen = tree_entry_len(entry->path, entry->sha1);
 
-	for (i = 0; i < opt->nr_paths; i++) {
-		const char *match = opt->paths[i];
-		int matchlen = opt->pathlens[i];
+	for (i = 0; i < nr_paths; i++) {
+		const char *match = paths[i];
+		int matchlen = pathlens[i];
 		int m = -1; /* signals that we haven't called strncmp() */
 
 		if (baselen >= matchlen) {
@@ -522,7 +517,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 			 * Does match sort strictly earlier than path
 			 * with their common parts?
 			 */
-			m = strncmp(match, path,
+			m = strncmp(match, entry->path,
 				    (matchlen < pathlen) ? matchlen : pathlen);
 			if (m < 0)
 				continue;
@@ -549,7 +544,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 		if (matchlen > pathlen) {
 			if (match[pathlen] != '/')
 				continue;
-			if (!S_ISDIR(mode))
+			if (!S_ISDIR(entry->mode))
 				continue;
 		}
 
@@ -558,7 +553,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 			 * we cheated and did not do strncmp(), so we do
 			 * that here.
 			 */
-			m = strncmp(match, path, pathlen);
+			m = strncmp(match, entry->path, pathlen);
 
 		/*
 		 * If common part matched earlier then it is a hit,
diff --git a/tree-walk.h b/tree-walk.h
index 88ea7e9..b20f3c4 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -57,4 +57,7 @@ static inline int traverse_path_len(const struct traverse_info *info, const stru
 	return info->pathlen + tree_entry_len(n->path, n->sha1);
 }
 
+extern int tree_entry_interesting(const struct name_entry *entry, const char *base, int baselen,
+				  const char **paths, int *pathlens, int nr_paths);
+
 #endif
-- 
1.7.1.rc1.69.g24c2f7