Add public API for pathspec matching

This adds a new public API for compiling pathspecs and matching
them against the working directory, the index, or a tree from the
repository.  This also reworks the pathspec internals to allow the
sharing of code between the existing internal usage of pathspec
matching and the new external API.

While this is working and the new API is ready for discussion, I
think there is still an incorrect behavior in which patterns are
always matched against the full path of an entry without taking
the subdirectories into account (so "s*" will match "subdir/file"
even though it wouldn't with core Git).  Further enhancements are
coming, but this was a good place to take a functional snapshot.

1 files changed, 401 insertions, 49 deletions

diff --git a/src/pathspec.c b/src/pathspec.c
index f029836d0..35421dbef 100644
--- a/src/pathspec.c
+++ b/src/pathspec.c
@@ -5,9 +5,13 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
+#include "git2/pathspec.h"
 #include "pathspec.h"
 #include "buf_text.h"
 #include "attr_file.h"
+#include "iterator.h"
+#include "repository.h"
+#include "index.h"
 
 /* what is the common non-wildcard prefix for all items in the pathspec */
 char *git_pathspec_prefix(const git_strarray *pathspec)
@@ -56,7 +60,7 @@ bool git_pathspec_is_empty(const git_strarray *pathspec)
 }
 
 /* build a vector of fnmatch patterns to evaluate efficiently */
-int git_pathspec_init(
+int git_pathspec__vinit(
 	git_vector *vspec, const git_strarray *strspec, git_pool *strpool)
 {
 	size_t i;
@@ -93,7 +97,7 @@ int git_pathspec_init(
 }
 
 /* free data from the pathspec vector */
-void git_pathspec_free(git_vector *vspec)
+void git_pathspec__vfree(git_vector *vspec)
 {
 	git_attr_fnmatch *match;
 	unsigned int i;
@@ -106,88 +110,436 @@ void git_pathspec_free(git_vector *vspec)
 	git_vector_free(vspec);
 }
 
+struct pathspec_match_context {
+	int fnmatch_flags;
+	int (*strcomp)(const char *, const char *);
+	int (*strncomp)(const char *, const char *, size_t);
+};
+
+static void pathspec_match_context_init(
+	struct pathspec_match_context *ctxt,
+	bool disable_fnmatch,
+	bool casefold)
+{
+	if (disable_fnmatch)
+		ctxt->fnmatch_flags = -1;
+	else if (casefold)
+		ctxt->fnmatch_flags = FNM_CASEFOLD;
+	else
+		ctxt->fnmatch_flags = 0;
+
+	if (casefold) {
+		ctxt->strcomp  = git__strcasecmp;
+		ctxt->strncomp = git__strncasecmp;
+	} else {
+		ctxt->strcomp  = git__strcmp;
+		ctxt->strncomp = git__strncmp;
+	}
+}
+
+static int pathspec_match_one(
+	const git_attr_fnmatch *match,
+	struct pathspec_match_context *ctxt,
+	const char *path)
+{
+	int result = (match->flags & GIT_ATTR_FNMATCH_MATCH_ALL) ? 0 : FNM_NOMATCH;
+
+	if (result == FNM_NOMATCH)
+		result = ctxt->strcomp(match->pattern, path) ? FNM_NOMATCH : 0;
+
+	if (ctxt->fnmatch_flags >= 0 && result == FNM_NOMATCH)
+		result = p_fnmatch(match->pattern, path, ctxt->fnmatch_flags);
+
+	/* if we didn't match, look for exact dirname prefix match */
+	if (result == FNM_NOMATCH &&
+		(match->flags & GIT_ATTR_FNMATCH_HASWILD) == 0 &&
+		ctxt->strncomp(path, match->pattern, match->length) == 0 &&
+		path[match->length] == '/')
+		result = 0;
+
+	if (result == 0)
+		return (match->flags & GIT_ATTR_FNMATCH_NEGATIVE) ? 0 : 1;
+	return -1;
+}
+
 /* match a path against the vectorized pathspec */
-bool git_pathspec_match_path(
-	git_vector *vspec,
+bool git_pathspec__match(
+	const git_vector *vspec,
 	const char *path,
 	bool disable_fnmatch,
 	bool casefold,
-	const char **matched_pathspec)
+	const char **matched_pathspec,
+	size_t *matched_at)
 {
 	size_t i;
-	git_attr_fnmatch *match;
-	int fnmatch_flags = 0;
-	int (*use_strcmp)(const char *, const char *);
-	int (*use_strncmp)(const char *, const char *, size_t);
+	const git_attr_fnmatch *match;
+	struct pathspec_match_context ctxt;
 
 	if (matched_pathspec)
 		*matched_pathspec = NULL;
+	if (matched_at)
+		*matched_at = GIT_PATHSPEC_NOMATCH;
 
 	if (!vspec || !vspec->length)
 		return true;
 
-	if (disable_fnmatch)
-		fnmatch_flags = -1;
-	else if (casefold)
-		fnmatch_flags = FNM_CASEFOLD;
+	pathspec_match_context_init(&ctxt, disable_fnmatch, casefold);
 
-	if (casefold) {
-		use_strcmp  = git__strcasecmp;
-		use_strncmp = git__strncasecmp;
-	} else {
-		use_strcmp  = git__strcmp;
-		use_strncmp = git__strncmp;
+	git_vector_foreach(vspec, i, match) {
+		int result = pathspec_match_one(match, &ctxt, path);
+
+		if (result >= 0) {
+			if (matched_pathspec)
+				*matched_pathspec = match->pattern;
+			if (matched_at)
+				*matched_at = i;
+
+			return (result != 0);
+		}
 	}
 
-	git_vector_foreach(vspec, i, match) {
-		int result = (match->flags & GIT_ATTR_FNMATCH_MATCH_ALL) ? 0 : FNM_NOMATCH;
+	return false;
+}
 
-		if (result == FNM_NOMATCH)
-			result = use_strcmp(match->pattern, path) ? FNM_NOMATCH : 0;
 
-		if (fnmatch_flags >= 0 && result == FNM_NOMATCH)
-			result = p_fnmatch(match->pattern, path, fnmatch_flags);
+int git_pathspec__init(git_pathspec *ps, const git_strarray *paths)
+{
+	int error = 0;
 
-		/* if we didn't match, look for exact dirname prefix match */
-		if (result == FNM_NOMATCH &&
-			(match->flags & GIT_ATTR_FNMATCH_HASWILD) == 0 &&
-			use_strncmp(path, match->pattern, match->length) == 0 &&
-			path[match->length] == '/')
-			result = 0;
+	memset(ps, 0, sizeof(*ps));
 
-		if (result == 0) {
-			if (matched_pathspec)
-				*matched_pathspec = match->pattern;
+	ps->prefix = git_pathspec_prefix(paths);
+
+	if ((error = git_pool_init(&ps->pool, 1, 0)) < 0 ||
+		(error = git_pathspec__vinit(&ps->pathspec, paths, &ps->pool)) < 0)
+		git_pathspec__clear(ps);
+
+	return error;
+}
+
+void git_pathspec__clear(git_pathspec *ps)
+{
+	git__free(ps->prefix);
+	git_pathspec__vfree(&ps->pathspec);
+	git_pool_clear(&ps->pool);
+	memset(ps, 0, sizeof(*ps));
+}
+
+int git_pathspec_new(git_pathspec **out, const git_strarray *pathspec)
+{
+	int error = 0;
+	git_pathspec *ps = git__malloc(sizeof(git_pathspec));
+	GITERR_CHECK_ALLOC(ps);
+
+	if ((error = git_pathspec__init(ps, pathspec)) < 0) {
+		git__free(ps);
+		return error;
+	}
+
+	GIT_REFCOUNT_INC(ps);
+	*out = ps;
+	return 0;
+}
+
+static void pathspec_free(git_pathspec *ps)
+{
+	git_pathspec__clear(ps);
+	git__free(ps);
+}
+
+void git_pathspec_free(git_pathspec *ps)
+{
+	if (!ps)
+		return;
+	GIT_REFCOUNT_DEC(ps, pathspec_free);
+}
 
-			return (match->flags & GIT_ATTR_FNMATCH_NEGATIVE) ? false : true;
+int git_pathspec_matches_path(
+	const git_pathspec *ps, uint32_t flags, const char *path)
+{
+	bool no_fnmatch = (flags & GIT_PATHSPEC_NO_GLOB) != 0;
+	bool casefold =  (flags & GIT_PATHSPEC_IGNORE_CASE) != 0;
+
+	assert(ps && path);
+
+	return (0 != git_pathspec__match(
+		&ps->pathspec, path, no_fnmatch, casefold, NULL, NULL));
+}
+
+static void pathspec_match_free(git_pathspec_match_list *m)
+{
+	git_pathspec_free(m->pathspec);
+	m->pathspec = NULL;
+
+	git_array_clear(m->matches);
+	git_array_clear(m->failures);
+	git_pool_clear(&m->pool);
+	git__free(m);
+}
+
+static git_pathspec_match_list *pathspec_match_alloc(git_pathspec *ps)
+{
+	git_pathspec_match_list *m = git__calloc(1, sizeof(git_pathspec_match_list));
+
+	if (m != NULL && git_pool_init(&m->pool, 1, 0) < 0) {
+		pathspec_match_free(m);
+		m = NULL;
+	}
+
+	/* need to keep reference to pathspec and increment refcount because
+	 * failures array stores pointers to the pattern strings of the
+	 * pathspec that had no matches
+	 */
+	GIT_REFCOUNT_INC(ps);
+	m->pathspec = ps;
+
+	return m;
+}
+
+GIT_INLINE(void) pathspec_mark_pattern(uint8_t *used, size_t pos, size_t *ct)
+{
+	if (!used[pos]) {
+		used[pos] = 1;
+		(*ct)++;
+	}
+}
+
+static int pathspec_match_from_iterator(
+	git_pathspec_match_list **out,
+	git_iterator *iter,
+	uint32_t flags,
+	git_pathspec *ps)
+{
+	int error = 0;
+	git_pathspec_match_list *m;
+	const git_index_entry *entry = NULL;
+	struct pathspec_match_context ctxt;
+	git_vector *patterns = &ps->pathspec;
+	bool find_failures = (flags & GIT_PATHSPEC_FIND_FAILURES) != 0;
+	bool failures_only = (flags & GIT_PATHSPEC_FAILURES_ONLY) != 0;
+	size_t pos, used_ct = 0, found_files = 0;
+	git_index *index = NULL;
+	uint8_t *used_patterns = NULL;
+	char **file;
+
+	*out = m = pathspec_match_alloc(ps);
+	GITERR_CHECK_ALLOC(m);
+
+	if ((error = git_iterator_reset(iter, ps->prefix, ps->prefix)) < 0)
+		goto done;
+
+	if (patterns->length > 0) {
+		used_patterns = git__calloc(patterns->length, sizeof(uint8_t));
+		GITERR_CHECK_ALLOC(used_patterns);
+	}
+
+	if (git_iterator_type(iter) == GIT_ITERATOR_TYPE_WORKDIR &&
+		(error = git_repository_index__weakptr(
+			&index, git_iterator_owner(iter))) < 0)
+		goto done;
+
+	pathspec_match_context_init(&ctxt,
+		(flags & GIT_PATHSPEC_NO_GLOB) != 0, git_iterator_ignore_case(iter));
+
+	while (!(error = git_iterator_advance(&entry, iter))) {
+		int result = -1;
+
+		for (pos = 0; pos < patterns->length; ++pos) {
+			const git_attr_fnmatch *pat = git_vector_get(patterns, pos);
+
+			result = pathspec_match_one(pat, &ctxt, entry->path);
+			if (result >= 0)
+				break;
+		}
+
+		/* no matches for this path */
+		if (result < 0)
+			continue;
+
+		/* if result was a negative pattern match, then don't list file */
+		if (!result) {
+			pathspec_mark_pattern(used_patterns, pos, &used_ct);
+			continue;
+		}
+
+		/* check if path is untracked and ignored */
+		if (index != NULL &&
+			git_iterator_current_is_ignored(iter) &&
+			git_index__find(NULL, index, entry->path, GIT_INDEX_STAGE_ANY) < 0)
+			continue;
+
+		/* mark the matched pattern as used */
+		pathspec_mark_pattern(used_patterns, pos, &used_ct);
+		++found_files;
+
+		/* if find_failures is on, check if any later patterns also match */
+		if (find_failures && used_ct < patterns->length) {
+			for (++pos; pos < patterns->length; ++pos) {
+				const git_attr_fnmatch *pat = git_vector_get(patterns, pos);
+				if (used_patterns[pos])
+					continue;
+
+				if (pathspec_match_one(pat, &ctxt, entry->path) > 0)
+					pathspec_mark_pattern(used_patterns, pos, &used_ct);
+			}
+		}
+
+		/* if only looking at failures, exit early or just continue */
+		if (failures_only) {
+			if (used_ct == patterns->length)
+				break;
+			continue;
+		}
+
+		/* insert matched path into matches array */
+		if ((file = git_array_alloc(m->matches)) == NULL ||
+			(*file = git_pool_strdup(&m->pool, entry->path)) == NULL) {
+			error = -1;
+			goto done;
 		}
 	}
 
-	return false;
+	if (error < 0 && error != GIT_ITEROVER)
+		goto done;
+	error = 0;
+
+	/* insert patterns that had no matches into failures array */
+	if (find_failures && used_ct < patterns->length) {
+		for (pos = 0; pos < patterns->length; ++pos) {
+			const git_attr_fnmatch *pat = git_vector_get(patterns, pos);
+			if (used_patterns[pos])
+				continue;
+
+			if ((file = git_array_alloc(m->failures)) == NULL ||
+				(*file = git_pool_strdup(&m->pool, pat->pattern)) == NULL) {
+				error = -1;
+				goto done;
+			}
+		}
+	}
+
+	/* if every pattern failed to match, then we have failed */
+	if ((flags & GIT_PATHSPEC_NO_MATCH_ERROR) != 0 && !found_files) {
+		giterr_set(GITERR_INVALID, "No matching files were found");
+		error = GIT_ENOTFOUND;
+	}
+
+done:
+	git__free(used_patterns);
+
+	if (error < 0) {
+		pathspec_match_free(m);
+		*out = NULL;
+	}
+
+	return error;
 }
 
+static git_iterator_flag_t pathspec_match_iter_flags(uint32_t flags)
+{
+	git_iterator_flag_t f = 0;
+
+	if ((flags & GIT_PATHSPEC_IGNORE_CASE) != 0)
+		f |= GIT_ITERATOR_IGNORE_CASE;
+	else if ((flags & GIT_PATHSPEC_USE_CASE) != 0)
+		f |= GIT_ITERATOR_DONT_IGNORE_CASE;
 
-int git_pathspec_context_init(
-	git_pathspec_context *ctxt, const git_strarray *paths)
+	return f;
+}
+
+int git_pathspec_match_workdir(
+	git_pathspec_match_list **out,
+	git_repository *repo,
+	uint32_t flags,
+	git_pathspec *ps)
 {
 	int error = 0;
+	git_iterator *iter;
+
+	assert(out && repo);
 
-	memset(ctxt, 0, sizeof(*ctxt));
+	if (!(error = git_iterator_for_workdir(
+			&iter, repo, pathspec_match_iter_flags(flags), NULL, NULL))) {
 
-	ctxt->prefix = git_pathspec_prefix(paths);
+		error = pathspec_match_from_iterator(out, iter, flags, ps);
 
-	if ((error = git_pool_init(&ctxt->pool, 1, 0)) < 0 ||
-		(error = git_pathspec_init(&ctxt->pathspec, paths, &ctxt->pool)) < 0)
-		git_pathspec_context_free(ctxt);
+		git_iterator_free(iter);
+	}
 
 	return error;
 }
 
-void git_pathspec_context_free(
-	git_pathspec_context *ctxt)
+int git_pathspec_match_index(
+	git_pathspec_match_list **out,
+	git_index *index,
+	uint32_t flags,
+	git_pathspec *ps)
+{
+	int error = 0;
+	git_iterator *iter;
+
+	assert(out && index);
+
+	if (!(error = git_iterator_for_index(
+			&iter, index, pathspec_match_iter_flags(flags), NULL, NULL))) {
+
+		error = pathspec_match_from_iterator(out, iter, flags, ps);
+
+		git_iterator_free(iter);
+	}
+
+	return error;
+}
+
+int git_pathspec_match_tree(
+	git_pathspec_match_list **out,
+	git_tree *tree,
+	uint32_t flags,
+	git_pathspec *ps)
+{
+	int error = 0;
+	git_iterator *iter;
+
+	assert(out && tree);
+
+	if (!(error = git_iterator_for_tree(
+			&iter, tree, pathspec_match_iter_flags(flags), NULL, NULL))) {
+
+		error = pathspec_match_from_iterator(out, iter, flags, ps);
+
+		git_iterator_free(iter);
+	}
+
+	return error;
+}
+
+void git_pathspec_match_list_free(git_pathspec_match_list *m)
+{
+	pathspec_match_free(m);
+}
+
+size_t git_pathspec_match_list_entrycount(
+	const git_pathspec_match_list *m)
+{
+	return git_array_size(m->matches);
+}
+
+const char *git_pathspec_match_list_entry(
+	const git_pathspec_match_list *m, size_t pos)
+{
+	char **entry = git_array_get(m->matches, pos);
+	return entry ? *entry : NULL;
+}
+
+size_t git_pathspec_match_list_failed_entrycount(
+	const git_pathspec_match_list *m)
+{
+	return git_array_size(m->failures);
+}
+
+const char * git_pathspec_match_list_failed_entry(
+	const git_pathspec_match_list *m, size_t pos)
 {
-	git__free(ctxt->prefix);
-	git_pathspec_free(&ctxt->pathspec);
-	git_pool_clear(&ctxt->pool);
-	memset(ctxt, 0, sizeof(*ctxt));
+	char **entry = git_array_get(m->failures, pos);
+	return entry ? *entry : NULL;
 }