Move pathspec code in separate files

Diff uses a `git_strarray` of path specs to represent a subset
of all files to be processed.  It is useful to be able to reuse
this filtering in other places outside diff, so I've moved it
into a standalone set of utilities.

1 files changed, 151 insertions, 0 deletions

diff --git a/src/pathspec.c b/src/pathspec.c
new file mode 100644
index 000000000..9632f5f13
--- /dev/null
+++ b/src/pathspec.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "pathspec.h"
+#include "attr_file.h"
+
+/* what is the common non-wildcard prefix for all items in the pathspec */
+char *git_pathspec_prefix(const git_strarray *pathspec)
+{
+	git_buf prefix = GIT_BUF_INIT;
+	const char *scan;
+
+	if (!pathspec || !pathspec->count ||
+		git_buf_common_prefix(&prefix, pathspec) < 0)
+		return NULL;
+
+	/* diff prefix will only be leading non-wildcards */
+	for (scan = prefix.ptr; *scan; ++scan) {
+		if (git__iswildcard(*scan) &&
+			(scan == prefix.ptr || (*(scan - 1) != '\\')))
+			break;
+	}
+	git_buf_truncate(&prefix, scan - prefix.ptr);
+
+	if (prefix.size <= 0) {
+		git_buf_free(&prefix);
+		return NULL;
+	}
+
+	git_buf_unescape(&prefix);
+
+	return git_buf_detach(&prefix);
+}
+
+/* is there anything in the spec that needs to be filtered on */
+bool git_pathspec_is_interesting(const git_strarray *pathspec)
+{
+	const char *str;
+
+	if (pathspec == NULL || pathspec->count == 0)
+		return false;
+	if (pathspec->count > 1)
+		return true;
+
+	str = pathspec->strings[0];
+	if (!str || !str[0] || (!str[1] && (str[0] == '*' || str[0] == '.')))
+		return false;
+	return true;
+}
+
+/* build a vector of fnmatch patterns to evaluate efficiently */
+int git_pathspec_init(
+	git_vector *vspec, const git_strarray *strspec, git_pool *strpool)
+{
+	size_t i;
+
+	memset(vspec, 0, sizeof(*vspec));
+
+	if (!git_pathspec_is_interesting(strspec))
+		return 0;
+
+	if (git_vector_init(vspec, strspec->count, NULL) < 0)
+		return -1;
+
+	for (i = 0; i < strspec->count; ++i) {
+		int ret;
+		const char *pattern = strspec->strings[i];
+		git_attr_fnmatch *match = git__calloc(1, sizeof(git_attr_fnmatch));
+		if (!match)
+			return -1;
+
+		match->flags = GIT_ATTR_FNMATCH_ALLOWSPACE;
+
+		ret = git_attr_fnmatch__parse(match, strpool, NULL, &pattern);
+		if (ret == GIT_ENOTFOUND) {
+			git__free(match);
+			continue;
+		} else if (ret < 0)
+			return ret;
+
+		if (git_vector_insert(vspec, match) < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
+/* free data from the pathspec vector */
+void git_pathspec_free(git_vector *vspec)
+{
+	git_attr_fnmatch *match;
+	unsigned int i;
+
+	git_vector_foreach(vspec, i, match) {
+		git__free(match);
+		vspec->contents[i] = NULL;
+	}
+
+	git_vector_free(vspec);
+}
+
+/* match a path against the vectorized pathspec */
+bool git_pathspec_match_path(
+	git_vector *vspec, const char *path, bool disable_fnmatch, bool casefold)
+{
+	unsigned int 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);
+
+	if (!vspec || !vspec->length)
+		return true;
+
+	if (disable_fnmatch)
+		fnmatch_flags = -1;
+	else if (casefold)
+		fnmatch_flags = FNM_CASEFOLD;
+
+	if (casefold) {
+		use_strcmp  = strcasecmp;
+		use_strncmp = strncasecmp;
+	} else {
+		use_strcmp  = strcmp;
+		use_strncmp = strncmp;
+	}
+
+	git_vector_foreach(vspec, i, match) {
+		int result = use_strcmp(match->pattern, path) ? FNM_NOMATCH : 0;
+
+		if (fnmatch_flags >= 0 && result == FNM_NOMATCH)
+			result = p_fnmatch(match->pattern, path, fnmatch_flags);
+
+		/* 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;
+
+		if (result == 0)
+			return (match->flags & GIT_ATTR_FNMATCH_NEGATIVE) ? false : true;
+	}
+
+	return false;
+}
+