merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/attr.h

@@ -0,0 +1,85 @@
+#ifndef ATTR_H
+#define ATTR_H
+
+struct index_state;
+
+/* An attribute is a pointer to this opaque structure */
+struct git_attr;
+
+/* opaque structures used internally for attribute collection */
+struct all_attrs_item;
+struct attr_stack;
+struct index_state;
+
+/*
+ * Given a string, return the gitattribute object that
+ * corresponds to it.
+ */
+const struct git_attr *git_attr(const char *);
+
+/* Internal use */
+extern const char git_attr__true[];
+extern const char git_attr__false[];
+
+/* For public to check git_attr_check results */
+#define ATTR_TRUE(v) ((v) == git_attr__true)
+#define ATTR_FALSE(v) ((v) == git_attr__false)
+#define ATTR_UNSET(v) ((v) == NULL)
+
+/*
+ * Send one or more git_attr_check to git_check_attrs(), and
+ * each 'value' member tells what its value is.
+ * Unset one is returned as NULL.
+ */
+struct attr_check_item {
+	const struct git_attr *attr;
+	const char *value;
+};
+
+struct attr_check {
+	int nr;
+	int alloc;
+	struct attr_check_item *items;
+	int all_attrs_nr;
+	struct all_attrs_item *all_attrs;
+	struct attr_stack *stack;
+};
+
+struct attr_check *attr_check_alloc(void);
+struct attr_check *attr_check_initl(const char *, ...);
+struct attr_check *attr_check_dup(const struct attr_check *check);
+
+struct attr_check_item *attr_check_append(struct attr_check *check,
+					  const struct git_attr *attr);
+
+void attr_check_reset(struct attr_check *check);
+void attr_check_clear(struct attr_check *check);
+void attr_check_free(struct attr_check *check);
+
+/*
+ * Return the name of the attribute represented by the argument.  The
+ * return value is a pointer to a null-delimited string that is part
+ * of the internal data structure; it should not be modified or freed.
+ */
+const char *git_attr_name(const struct git_attr *);
+
+void git_check_attr(const struct index_state *istate,
+		    const char *path, struct attr_check *check);
+
+/*
+ * Retrieve all attributes that apply to the specified path.
+ * check holds the attributes and their values.
+ */
+void git_all_attrs(const struct index_state *istate,
+		   const char *path, struct attr_check *check);
+
+enum git_attr_direction {
+	GIT_ATTR_CHECKIN,
+	GIT_ATTR_CHECKOUT,
+	GIT_ATTR_INDEX
+};
+void git_attr_set_direction(enum git_attr_direction new_direction);
+
+void attr_start(void);
+
+#endif /* ATTR_H */