[PATCH v2 0/4] nd/pathspec-wildcard

[PATCH v2 0/4] nd/pathspec-wildcard

[Nguyễn Thái Ngọc Duy]

The only change (apart from what Junio's made after I sent the series)
is rename GF_* to GFNM_* and PSF_* to PATHSPEC_* with a brief explanation
for each flag.

.gitignore code does not have "foo*oob" bug that the original series has.

Nguyễn Thái Ngọc Duy (4):
  pathspec: save the non-wildcard length part
  pathspec: do exact comparison on the leading non-wildcard part
  pathspec: apply "*.c" optimization from exclude
  tree_entry_interesting: do basedir compare on wildcard patterns when
    possible

 builtin/ls-files.c |  2 +-
 builtin/ls-tree.c  |  2 +-
 cache.h            |  5 +++-
 dir.c              | 36 +++++++++++++++++++++++---
 dir.h              |  9 +++++++
 tree-walk.c        | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 6 files changed, 118 insertions(+), 11 deletions(-)

-- 
1.8.0.rc2.23.g1fb49df

[PATCH v2 1/4] pathspec: save the non-wildcard length part

[Nguyễn Thái Ngọc Duy]

We mark pathspec with wildcards with the field use_wildcard. We
could do better by saving the length of the non-wildcard part, which
can be used for optimizations such as f9f6e2c (exclude: do strcmp as
much as possible before fnmatch - 2012-06-07).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/ls-files.c | 2 +-
 builtin/ls-tree.c  | 2 +-
 cache.h            | 2 +-
 dir.c              | 6 +++---
 tree-walk.c        | 4 ++--
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index b5434af..4a9ee69 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -337,7 +337,7 @@ void overlay_tree_on_cache(const char *tree_name, const char *prefix)
 		matchbuf[0] = prefix;
 		matchbuf[1] = NULL;
 		init_pathspec(&pathspec, matchbuf);
-		pathspec.items[0].use_wildcard = 0;
+		pathspec.items[0].nowildcard_len = pathspec.items[0].len;
 	} else
 		init_pathspec(&pathspec, NULL);
 	if (read_tree(tree, 1, &pathspec))
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index 235c17c..fb76e38 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -168,7 +168,7 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 
 	init_pathspec(&pathspec, get_pathspec(prefix, argv + 1));
 	for (i = 0; i < pathspec.nr; i++)
-		pathspec.items[i].use_wildcard = 0;
+		pathspec.items[i].nowildcard_len = pathspec.items[i].len;
 	pathspec.has_wildcard = 0;
 	tree = parse_tree_indirect(sha1);
 	if (!tree)
diff --git a/cache.h b/cache.h
index dbd8018..bf031f1 100644
--- a/cache.h
+++ b/cache.h
@@ -482,7 +482,7 @@ struct pathspec {
 	struct pathspec_item {
 		const char *match;
 		int len;
-		unsigned int use_wildcard:1;
+		int nowildcard_len;
 	} *items;
 };
 
diff --git a/dir.c b/dir.c
index 5a83aa7..c391d46 100644
--- a/dir.c
+++ b/dir.c
@@ -230,7 +230,7 @@ static int match_pathspec_item(const struct pathspec_item *item, int prefix,
 			return MATCHED_RECURSIVELY;
 	}
 
-	if (item->use_wildcard && !fnmatch(match, name, 0))
+	if (item->nowildcard_len < item->len && !fnmatch(match, name, 0))
 		return MATCHED_FNMATCH;
 
 	return 0;
@@ -1429,8 +1429,8 @@ int init_pathspec(struct pathspec *pathspec, const char **paths)
 
 		item->match = path;
 		item->len = strlen(path);
-		item->use_wildcard = !no_wildcard(path);
-		if (item->use_wildcard)
+		item->nowildcard_len = simple_length(path);
+		if (item->nowildcard_len < item->len)
 			pathspec->has_wildcard = 1;
 	}
 
diff --git a/tree-walk.c b/tree-walk.c
index 3f54c02..af871c5 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -626,7 +626,7 @@ enum interesting tree_entry_interesting(const struct name_entry *entry,
 					&never_interesting))
 				return entry_interesting;
 
-			if (item->use_wildcard) {
+			if (item->nowildcard_len < item->len) {
 				if (!fnmatch(match + baselen, entry->path, 0))
 					return entry_interesting;
 
@@ -642,7 +642,7 @@ enum interesting tree_entry_interesting(const struct name_entry *entry,
 		}
 
 match_wildcards:
-		if (!item->use_wildcard)
+		if (item->nowildcard_len == item->len)
 			continue;
 
 		/*
-- 
1.8.0.rc2.23.g1fb49df

[PATCH v2 2/4] pathspec: do exact comparison on the leading non-wildcard part

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 dir.c       | 18 +++++++++++++++++-
 dir.h       |  8 ++++++++
 tree-walk.c |  6 ++++--
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/dir.c b/dir.c
index c391d46..f81e1d2 100644
--- a/dir.c
+++ b/dir.c
@@ -34,6 +34,21 @@ int fnmatch_icase(const char *pattern, const char *string, int flags)
 	return fnmatch(pattern, string, flags | (ignore_case ? FNM_CASEFOLD : 0));
 }
 
+inline int git_fnmatch(const char *pattern, const char *string,
+		       int flags, int prefix)
+{
+	int fnm_flags = 0;
+	if (flags & GFNM_PATHNAME)
+		fnm_flags |= FNM_PATHNAME;
+	if (prefix > 0) {
+		if (strncmp(pattern, string, prefix))
+			return FNM_NOMATCH;
+		pattern += prefix;
+		string += prefix;
+	}
+	return fnmatch(pattern, string, fnm_flags);
+}
+
 static size_t common_prefix_len(const char **pathspec)
 {
 	const char *n, *first;
@@ -230,7 +245,8 @@ static int match_pathspec_item(const struct pathspec_item *item, int prefix,
 			return MATCHED_RECURSIVELY;
 	}
 
-	if (item->nowildcard_len < item->len && !fnmatch(match, name, 0))
+	if (item->nowildcard_len < item->len &&
+	    !git_fnmatch(match, name, 0, item->nowildcard_len - prefix))
 		return MATCHED_FNMATCH;
 
 	return 0;
diff --git a/dir.h b/dir.h
index f5c89e3..0e8ae84 100644
--- a/dir.h
+++ b/dir.h
@@ -139,4 +139,12 @@ extern int strcmp_icase(const char *a, const char *b);
 extern int strncmp_icase(const char *a, const char *b, size_t count);
 extern int fnmatch_icase(const char *pattern, const char *string, int flags);
 
+/*
+ * The prefix part of pattern must not contains wildcards.
+ */
+#define GFNM_PATHNAME 1		/* similar to FNM_PATHNAME */
+
+extern int git_fnmatch(const char *pattern, const char *string,
+		       int flags, int prefix);
+
 #endif
diff --git a/tree-walk.c b/tree-walk.c
index af871c5..2fcf3c0 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -627,7 +627,8 @@ enum interesting tree_entry_interesting(const struct name_entry *entry,
 				return entry_interesting;
 
 			if (item->nowildcard_len < item->len) {
-				if (!fnmatch(match + baselen, entry->path, 0))
+				if (!git_fnmatch(match + baselen, entry->path,
+						 0, item->nowildcard_len - baselen))
 					return entry_interesting;
 
 				/*
@@ -652,7 +653,8 @@ match_wildcards:
 
 		strbuf_add(base, entry->path, pathlen);
 
-		if (!fnmatch(match, base->buf + base_offset, 0)) {
+		if (!git_fnmatch(match, base->buf + base_offset,
+				 0, item->nowildcard_len)) {
 			strbuf_setlen(base, base_offset + baselen);
 			return entry_interesting;
 		}
-- 
1.8.0.rc2.23.g1fb49df

[PATCH v2 3/4] pathspec: apply "*.c" optimization from exclude

[Nguyễn Thái Ngọc Duy]

When a pattern contains only a single asterisk as wildcard,
e.g. "foo*bar", after literally comparing the leading part "foo" with
the string, we can compare the tail of the string and make sure it
matches "bar", instead of running fnmatch() on "*bar" against the
remainder of the string.

-O2 build on linux-2.6, without the patch:

$ time git rev-list --quiet HEAD -- '*.c'

real    0m40.770s
user    0m40.290s
sys     0m0.256s

With the patch

$ time ~/w/git/git rev-list --quiet HEAD -- '*.c'

real    0m34.288s
user    0m33.997s
sys     0m0.205s

The above command is not supposed to be widely popular. It's chosen
because it exercises pathspec matching a lot. The point is it cuts
down matching time for popular patterns like *.c, which could be used
as pathspec in other places.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 The optimization's condition could be loosen to "only one asterisk"
 (iow, fixed-length wildcards are OK, e.g. "abc[de]gh*.[ch]") when we
 have a custom fnmatch implementation that supports dry-run, so it can
 parse the pattern and determine the actual string length of
 "abc[de]gh" and ".[ch]". We would have something similar to regcomp in
 addition to git_fnmatch().

 cache.h     |  3 +++
 dir.c       | 18 ++++++++++++++++--
 dir.h       |  1 +
 tree-walk.c |  6 ++++--
 4 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/cache.h b/cache.h
index bf031f1..babf9e5 100644
--- a/cache.h
+++ b/cache.h
@@ -473,6 +473,8 @@ extern int index_name_is_other(const struct index_state *, const char *, int);
 extern int ie_match_stat(const struct index_state *, struct cache_entry *, struct stat *, unsigned int);
 extern int ie_modified(const struct index_state *, struct cache_entry *, struct stat *, unsigned int);
 
+#define PATHSPEC_ONESTAR 1	/* the pathspec pattern sastisfies GFNM_ONESTAR */
+
 struct pathspec {
 	const char **raw; /* get_pathspec() result, not freed by free_pathspec() */
 	int nr;
@@ -483,6 +485,7 @@ struct pathspec {
 		const char *match;
 		int len;
 		int nowildcard_len;
+		int flags;
 	} *items;
 };
 
diff --git a/dir.c b/dir.c
index f81e1d2..9afd388 100644
--- a/dir.c
+++ b/dir.c
@@ -46,6 +46,13 @@ inline int git_fnmatch(const char *pattern, const char *string,
 		pattern += prefix;
 		string += prefix;
 	}
+	if (flags & GFNM_ONESTAR) {
+		int pattern_len = strlen(++pattern);
+		int string_len = strlen(string);
+		return string_len < pattern_len ||
+		       strcmp(pattern,
+			      string + string_len - pattern_len);
+	}
 	return fnmatch(pattern, string, fnm_flags);
 }
 
@@ -246,7 +253,9 @@ static int match_pathspec_item(const struct pathspec_item *item, int prefix,
 	}
 
 	if (item->nowildcard_len < item->len &&
-	    !git_fnmatch(match, name, 0, item->nowildcard_len - prefix))
+	    !git_fnmatch(match, name,
+			 item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
+			 item->nowildcard_len - prefix))
 		return MATCHED_FNMATCH;
 
 	return 0;
@@ -1446,8 +1455,13 @@ int init_pathspec(struct pathspec *pathspec, const char **paths)
 		item->match = path;
 		item->len = strlen(path);
 		item->nowildcard_len = simple_length(path);
-		if (item->nowildcard_len < item->len)
+		item->flags = 0;
+		if (item->nowildcard_len < item->len) {
 			pathspec->has_wildcard = 1;
+			if (path[item->nowildcard_len] == '*' &&
+			    no_wildcard(path + item->nowildcard_len + 1))
+				item->flags |= PATHSPEC_ONESTAR;
+		}
 	}
 
 	qsort(pathspec->items, pathspec->nr,
diff --git a/dir.h b/dir.h
index 0e8ae84..ab5af42 100644
--- a/dir.h
+++ b/dir.h
@@ -143,6 +143,7 @@ extern int fnmatch_icase(const char *pattern, const char *string, int flags);
  * The prefix part of pattern must not contains wildcards.
  */
 #define GFNM_PATHNAME 1		/* similar to FNM_PATHNAME */
+#define GFNM_ONESTAR  2		/* there is only _one_ wildcard, a star */
 
 extern int git_fnmatch(const char *pattern, const char *string,
 		       int flags, int prefix);
diff --git a/tree-walk.c b/tree-walk.c
index 2fcf3c0..585899e 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -628,7 +628,8 @@ enum interesting tree_entry_interesting(const struct name_entry *entry,
 
 			if (item->nowildcard_len < item->len) {
 				if (!git_fnmatch(match + baselen, entry->path,
-						 0, item->nowildcard_len - baselen))
+						 item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
+						 item->nowildcard_len - baselen))
 					return entry_interesting;
 
 				/*
@@ -654,7 +655,8 @@ match_wildcards:
 		strbuf_add(base, entry->path, pathlen);
 
 		if (!git_fnmatch(match, base->buf + base_offset,
-				 0, item->nowildcard_len)) {
+				 item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
+				 item->nowildcard_len)) {
 			strbuf_setlen(base, base_offset + baselen);
 			return entry_interesting;
 		}
-- 
1.8.0.rc2.23.g1fb49df

[PATCH v2 4/4] tree_entry_interesting: do basedir compare on wildcard patterns when possible

[Nguyễn Thái Ngọc Duy]

Currently we treat "*.c" and "path/to/*.c" the same way. Which means
we check all possible paths in repo against "path/to/*.c". One could
see that "path/elsewhere/foo.c" obviously cannot match "path/to/*.c"
and we only need to check all paths _inside_ "path/to/" against that
pattern.

This patch checks the leading fixed part of a pathspec against base
directory and exit early if possible. We could even optimize further
in "path/to/something*.c" case (i.e. check the fixed part against
name_entry as well) but that's more complicated and probably does not
gain us much.

-O2 build on linux-2.6, without and with this patch respectively:

$ time git rev-list --quiet HEAD -- 'drivers/*.c'

real    1m9.484s
user    1m9.128s
sys     0m0.181s

$ time ~/w/git/git rev-list --quiet HEAD -- 'drivers/*.c'

real    0m15.710s
user    0m15.564s
sys     0m0.107s

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 tree-walk.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/tree-walk.c b/tree-walk.c
index 585899e..9d6e59b 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -573,6 +573,52 @@ static int match_dir_prefix(const char *base,
 }
 
 /*
+ * Perform matching on the leading non-wildcard part of
+ * pathspec. item->nowildcard_len must be greater than zero. Return
+ * non-zero if base is matched.
+ */
+static int match_wildcard_base(const struct pathspec_item *item,
+			       const char *base, int baselen,
+			       int *matched)
+{
+	const char *match = item->match;
+	/* the wildcard part is not considered in this function */
+	int matchlen = item->nowildcard_len;
+
+	if (baselen) {
+		int dirlen;
+		/*
+		 * Return early if base is longer than the
+		 * non-wildcard part but it does not match.
+		 */
+		if (baselen >= matchlen) {
+			*matched = matchlen;
+			return !strncmp(base, match, matchlen);
+		}
+
+		dirlen = matchlen;
+		while (dirlen && match[dirlen - 1] != '/')
+			dirlen--;
+
+		/* Return early if base is shorter than the
+		   non-wildcard part but it does not match. Note that
+		   base ends with '/' so we are sure it really matches
+		   directory */
+		if (strncmp(base, match, baselen))
+			return 0;
+		*matched = baselen;
+	} else
+		*matched = 0;
+	/*
+	 * we could have checked entry against the non-wildcard part
+	 * that is not in base and does similar never_interesting
+	 * optimization as in match_entry. For now just be happy with
+	 * base comparison.
+	 */
+	return entry_interesting;
+}
+
+/*
  * Is a tree entry interesting given the pathspec we have?
  *
  * Pre-condition: either baselen == base_offset (i.e. empty path)
@@ -602,7 +648,7 @@ enum interesting tree_entry_interesting(const struct name_entry *entry,
 		const struct pathspec_item *item = ps->items+i;
 		const char *match = item->match;
 		const char *base_str = base->buf + base_offset;
-		int matchlen = item->len;
+		int matchlen = item->len, matched = 0;
 
 		if (baselen >= matchlen) {
 			/* If it doesn't match, move along... */
@@ -647,9 +693,24 @@ match_wildcards:
 		if (item->nowildcard_len == item->len)
 			continue;
 
+		if (item->nowildcard_len &&
+		    !match_wildcard_base(item, base_str, baselen, &matched))
+			return entry_not_interesting;
+
 		/*
 		 * Concatenate base and entry->path into one and do
 		 * fnmatch() on it.
+		 *
+		 * While we could avoid concatenation in certain cases
+		 * [1], which saves a memcpy and potentially a
+		 * realloc, it turns out not worth it. Measurement on
+		 * linux-2.6 does not show any clear improvements,
+		 * partly because of the nowildcard_len optimization
+		 * in git_fnmatch(). Avoid micro-optimizations here.
+		 *
+		 * [1] if match_wildcard_base() says the base
+		 * directory is already matched, we only need to match
+		 * the rest, which is shorter so _in theory_ faster.
 		 */
 
 		strbuf_add(base, entry->path, pathlen);
-- 
1.8.0.rc2.23.g1fb49df