diff options
Diffstat (limited to 'attr.h')
| -rw-r--r-- | attr.h | 141 |
1 files changed, 134 insertions, 7 deletions
diff --git a/attr.h b/attr.h index b0378bfe5fea..404548f028a8 100644 --- a/attr.h +++ b/attr.h @@ -1,9 +1,121 @@ #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 a pointer to this opaque structure */ +/** + * 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 */ @@ -21,21 +133,36 @@ const struct git_attr *git_attr(const char *); extern const char git_attr__true[]; extern const char git_attr__false[]; -/* For public to check git_attr_check results */ +/** + * 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) -/* - * 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. - */ +/* 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; |