Add git_pathspec_match_diff API

This adds an additional pathspec API that will match a pathspec
against a diff object.  This is convenient if you want to handle
renames (so you need the whole diff and can't use the pathspec
constraint built into the diff API) but still want to tell if the
diff had any files that matched the pathspec.

When the pathspec is matched against a diff, instead of keeping
a list of filenames that matched, instead the API keeps the list
of git_diff_deltas that matched and they can be retrieved via a
new API git_pathspec_match_list_diff_entry.

There are a couple of other minor API extensions here that were
mostly for the sake of convenience and to reduce dependencies
on knowing the internal data structure between files inside the
library.

include/git2/diff.h

@@ -798,6 +798,14 @@ GIT_EXTERN(size_t) git_diff_num_deltas_of_type(
 	git_delta_t type);
 
 /**
+ * Check if deltas are sorted case sensitively or insensitively.
+ *
+ * @param diff Diff list to check
+ * @return 0 if case sensitive, 1 if case is ignored
+ */
+GIT_EXTERN(int) git_diff_is_sorted_icase(const git_diff_list *diff);
+
+/**
  * Return the diff delta and patch for an entry in the diff list.
  *
  * The `git_diff_patch` is a newly created object contains the text diffs

include/git2/pathspec.h

@@ -10,6 +10,7 @@
 #include "common.h"
 #include "types.h"
 #include "strarray.h"
+#include "diff.h"
 
 /**
  * Compiled pathspec
@@ -167,6 +168,30 @@ GIT_EXTERN(int) git_pathspec_match_tree(
 	git_pathspec *ps);
 
 /**
+ * Match a pathspec against files in a diff list.
+ *
+ * This matches the pathspec against the files in the given diff list.
+ *
+ * If `out` is not NULL, this returns a `git_patchspec_match_list`.  That
+ * contains the list of all matched filenames (unless you pass the
+ * `GIT_PATHSPEC_FAILURES_ONLY` flag) and may also contain the list of
+ * pathspecs with no match (if you used the `GIT_PATHSPEC_FIND_FAILURES`
+ * flag).  You must call `git_pathspec_match_list_free()` on this object.
+ *
+ * @param out Output list of matches; pass NULL to just get return value
+ * @param diff A generated diff list
+ * @param flags Combination of git_pathspec_flag_t options to control match
+ * @param ps Pathspec to be matched
+ * @return 0 on success, -1 on error, GIT_ENOTFOUND if no matches and
+ *         the GIT_PATHSPEC_NO_MATCH_ERROR flag is used
+ */
+GIT_EXTERN(int) git_pathspec_match_diff(
+	git_pathspec_match_list **out,
+	git_diff_list *diff,
+	uint32_t flags,
+	git_pathspec *ps);
+
+/**
  * Free memory associates with a git_pathspec_match_list
  *
  * @param m The git_pathspec_match_list to be freed
@@ -185,6 +210,9 @@ GIT_EXTERN(size_t) git_pathspec_match_list_entrycount(
 /**
  * Get a matching filename by position.
  *
+ * This routine cannot be used if the match list was generated by
+ * `git_pathspec_match_diff`.  If so, it will always return NULL.
+ *
  * @param m The git_pathspec_match_list object
  * @param pos The index into the list
  * @return The filename of the match
@@ -193,6 +221,19 @@ GIT_EXTERN(const char *) git_pathspec_match_list_entry(
 	const git_pathspec_match_list *m, size_t pos);
 
 /**
+ * Get a matching diff delta by position.
+ *
+ * This routine can only be used if the match list was generated by
+ * `git_pathspec_match_diff`.  Otherwise it will always return NULL.
+ *
+ * @param m The git_pathspec_match_list object
+ * @param pos The index into the list
+ * @return The filename of the match
+ */
+GIT_EXTERN(const git_diff_delta *) git_pathspec_match_list_diff_entry(
+	const git_pathspec_match_list *m, size_t pos);
+
+/**
  * Get the number of pathspec items that did not match.
  *
  * This will be zero unless you passed GIT_PATHSPEC_FIND_FAILURES when

src/array.h

@@ -66,4 +66,6 @@ GIT_INLINE(void *) git_array_grow(git_array_generic_t *a, size_t item_size)
 
 #define git_array_size(a) (a).size
 
+#define git_array_valid_index(a, i) ((i) < (a).size)
+
 #endif

src/diff.c

@@ -247,6 +247,11 @@ GIT_INLINE(const char *) diff_delta__path(const git_diff_delta *delta)
 	return str;
 }
 
+const char *git_diff_delta__path(const git_diff_delta *delta)
+{
+	return diff_delta__path(delta);
+}
+
 int git_diff_delta__cmp(const void *a, const void *b)
 {
 	const git_diff_delta *da = a, *db = b;
@@ -1235,6 +1240,11 @@ size_t git_diff_num_deltas_of_type(git_diff_list *diff, git_delta_t type)
 	return count;
 }
 
+int git_diff_is_sorted_icase(const git_diff_list *diff)
+{
+	return (diff->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0;
+}
+
 int git_diff__paired_foreach(
 	git_diff_list *head2idx,
 	git_diff_list *idx2wd,

src/diff.h

@@ -76,6 +76,8 @@ extern void git_diff_list_addref(git_diff_list *diff);
 extern int git_diff_delta__cmp(const void *a, const void *b);
 extern int git_diff_delta__casecmp(const void *a, const void *b);
 
+extern const char *git_diff_delta__path(const git_diff_delta *delta);
+
 extern bool git_diff_delta__should_skip(
 	const git_diff_options *opts, const git_diff_delta *delta);
 

src/pathspec.h

@@ -22,12 +22,20 @@ struct git_pathspec {
 	git_pool pool;
 };
 
+enum {
+	PATHSPEC_DATATYPE_STRINGS = 0,
+	PATHSPEC_DATATYPE_DIFF = 1,
+};
+
+typedef git_array_t(char *) git_pathspec_string_array_t;
+
 /* public interface to pathspec matching */
 struct git_pathspec_match_list {
 	git_pathspec *pathspec;
-	git_array_t(char *) matches;
-	git_array_t(char *) failures;
+	git_array_t(void *) matches;
+	git_pathspec_string_array_t failures;
 	git_pool pool;
+	int datatype;
 };
 
 /* what is the common non-wildcard prefix for all items in the pathspec */

tests-clar/diff/pathspec.c

+#include "clar_libgit2.h"
+#include "diff_helpers.h"
+
+static git_repository *g_repo = NULL;
+
+void test_diff_pathspec__initialize(void)
+{
+	g_repo = cl_git_sandbox_init("status");
+}
+
+void test_diff_pathspec__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_diff_pathspec__0(void)
+{
+	const char *a_commit = "26a125ee"; /* the current HEAD */
+	const char *b_commit = "0017bd4a"; /* the start */
+	git_tree *a = resolve_commit_oid_to_tree(g_repo, a_commit);
+	git_tree *b = resolve_commit_oid_to_tree(g_repo, b_commit);
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	git_diff_list *diff = NULL;
+	git_strarray paths = { NULL, 1 };
+	char *path;
+	git_pathspec *ps;
+	git_pathspec_match_list *matches;
+
+	cl_assert(a);
+	cl_assert(b);
+
+	path = "*_file";
+	paths.strings = &path;
+	cl_git_pass(git_pathspec_new(&ps, &paths));
+
+	cl_git_pass(git_pathspec_match_tree(&matches, a, GIT_PATHSPEC_DEFAULT, ps));
+	cl_assert_equal_i(7, git_pathspec_match_list_entrycount(matches));
+	cl_assert_equal_s("current_file", git_pathspec_match_list_entry(matches,0));
+	cl_assert(git_pathspec_match_list_diff_entry(matches,0) == NULL);
+	git_pathspec_match_list_free(matches);
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, g_repo, NULL, a, &opts));
+
+	cl_git_pass(git_pathspec_match_diff(
+		&matches, diff, GIT_PATHSPEC_DEFAULT, ps));
+	cl_assert_equal_i(7, git_pathspec_match_list_entrycount(matches));
+	cl_assert(git_pathspec_match_list_diff_entry(matches, 0) != NULL);
+	cl_assert(git_pathspec_match_list_entry(matches, 0) == NULL);
+	cl_assert_equal_s("current_file",
+		git_pathspec_match_list_diff_entry(matches,0)->new_file.path);
+	cl_assert_equal_i(GIT_DELTA_ADDED,
+		git_pathspec_match_list_diff_entry(matches,0)->status);
+	git_pathspec_match_list_free(matches);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, g_repo, a, b, &opts));
+
+	cl_git_pass(git_pathspec_match_diff(
+		&matches, diff, GIT_PATHSPEC_DEFAULT, ps));
+	cl_assert_equal_i(3, git_pathspec_match_list_entrycount(matches));
+	cl_assert(git_pathspec_match_list_diff_entry(matches, 0) != NULL);
+	cl_assert(git_pathspec_match_list_entry(matches, 0) == NULL);
+	cl_assert_equal_s("subdir/current_file",
+		git_pathspec_match_list_diff_entry(matches,0)->new_file.path);
+	cl_assert_equal_i(GIT_DELTA_DELETED,
+		git_pathspec_match_list_diff_entry(matches,0)->status);
+	git_pathspec_match_list_free(matches);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	cl_git_pass(git_diff_tree_to_workdir(&diff, g_repo, a, &opts));
+
+	cl_git_pass(git_pathspec_match_diff(
+		&matches, diff, GIT_PATHSPEC_DEFAULT, ps));
+	cl_assert_equal_i(4, git_pathspec_match_list_entrycount(matches));
+	cl_assert(git_pathspec_match_list_diff_entry(matches, 0) != NULL);
+	cl_assert(git_pathspec_match_list_entry(matches, 0) == NULL);
+	cl_assert_equal_s("modified_file",
+		git_pathspec_match_list_diff_entry(matches,0)->new_file.path);
+	cl_assert_equal_i(GIT_DELTA_MODIFIED,
+		git_pathspec_match_list_diff_entry(matches,0)->status);
+	git_pathspec_match_list_free(matches);
+
+	git_diff_list_free(diff);
+	diff = NULL;
+
+	git_tree_free(a);
+	git_tree_free(b);
+}