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Diffstat (limited to 'third_party/git/attr.h')
| -rw-r--r-- | third_party/git/attr.h | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/third_party/git/attr.h b/third_party/git/attr.h new file mode 100644 index 000000000000..404548f028a8 --- /dev/null +++ b/third_party/git/attr.h @@ -0,0 +1,212 @@ +#ifndef ATTR_H +#define ATTR_H + +/** + * gitattributes mechanism gives a uniform way to associate various attributes + * to set of paths. + * + * + * Querying Specific Attributes + * ---------------------------- + * + * - Prepare `struct attr_check` using attr_check_initl() function, enumerating + * the names of attributes whose values you are interested in, terminated with + * a NULL pointer. Alternatively, an empty `struct attr_check` can be + * prepared by calling `attr_check_alloc()` function and then attributes you + * want to ask about can be added to it with `attr_check_append()` function. + * + * - Call `git_check_attr()` to check the attributes for the path. + * + * - Inspect `attr_check` structure to see how each of the attribute in the + * array is defined for the path. + * + * + * Example + * ------- + * + * To see how attributes "crlf" and "ident" are set for different paths. + * + * - Prepare a `struct attr_check` with two elements (because we are checking + * two attributes): + * + * ------------ + * static struct attr_check *check; + * static void setup_check(void) + * { + * if (check) + * return; // already done + * check = attr_check_initl("crlf", "ident", NULL); + * } + * ------------ + * + * - Call `git_check_attr()` with the prepared `struct attr_check`: + * + * ------------ + * const char *path; + * + * setup_check(); + * git_check_attr(path, check); + * ------------ + * + * - Act on `.value` member of the result, left in `check->items[]`: + * + * ------------ + * const char *value = check->items[0].value; + * + * if (ATTR_TRUE(value)) { + * The attribute is Set, by listing only the name of the + * attribute in the gitattributes file for the path. + * } else if (ATTR_FALSE(value)) { + * The attribute is Unset, by listing the name of the + * attribute prefixed with a dash - for the path. + * } else if (ATTR_UNSET(value)) { + * The attribute is neither set nor unset for the path. + * } else if (!strcmp(value, "input")) { + * If none of ATTR_TRUE(), ATTR_FALSE(), or ATTR_UNSET() is + * true, the value is a string set in the gitattributes + * file for the path by saying "attr=value". + * } else if (... other check using value as string ...) { + * ... + * } + * ------------ + * + * To see how attributes in argv[] are set for different paths, only + * the first step in the above would be different. + * + * ------------ + * static struct attr_check *check; + * static void setup_check(const char **argv) + * { + * check = attr_check_alloc(); + * while (*argv) { + * struct git_attr *attr = git_attr(*argv); + * attr_check_append(check, attr); + * argv++; + * } + * } + * ------------ + * + * + * Querying All Attributes + * ----------------------- + * + * To get the values of all attributes associated with a file: + * + * - Prepare an empty `attr_check` structure by calling `attr_check_alloc()`. + * + * - Call `git_all_attrs()`, which populates the `attr_check` with the + * attributes attached to the path. + * + * - Iterate over the `attr_check.items[]` array to examine the attribute + * names and values. The name of the attribute described by an + * `attr_check.items[]` object can be retrieved via + * `git_attr_name(check->items[i].attr)`. (Please note that no items will be + * returned for unset attributes, so `ATTR_UNSET()` will return false for all + * returned `attr_check.items[]` objects.) + * + * - Free the `attr_check` struct by calling `attr_check_free()`. + */ + +struct index_state; + +/** + * An attribute is an opaque object that is identified by its name. Pass the + * name to `git_attr()` function to obtain the object of this type. + * The internal representation of this structure is of no interest to the + * calling programs. The name of the attribute can be retrieved by calling + * `git_attr_name()`. + */ +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[]; + +/** + * Attribute Values + * ---------------- + * + * An attribute for a path can be in one of four states: Set, Unset, Unspecified + * or set to a string, and `.value` member of `struct attr_check_item` records + * it. The three macros check these, if none of them returns true, `.value` + * member points at a string value of the attribute for the path. + */ + +/* Returns true if the attribute is Set for the path. */ +#define ATTR_TRUE(v) ((v) == git_attr__true) + +/* Returns true if the attribute is Unset for the path. */ +#define ATTR_FALSE(v) ((v) == git_attr__false) + +/* Returns true if the attribute is Unspecified for the path. */ +#define ATTR_UNSET(v) ((v) == NULL) + +/* This structure represents one attribute and its value. */ +struct attr_check_item { + const struct git_attr *attr; + const char *value; +}; + +/** + * This structure represents a collection of `attr_check_item`. It is passed to + * `git_check_attr()` function, specifying the attributes to check, and + * receives their values. + */ +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 */ |