Revision cbf04937d5b9fcf0a76c28f69e6294e9e3ecd7e6 authored by Johannes Schindelin on 06 February 2023, 08:43:41 UTC, committed by Johannes Schindelin on 06 February 2023, 08:43:41 UTC
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent 3aef76f
attr.h
#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()`.
*/
/**
* The maximum line length for a gitattributes file. If the line exceeds this
* length we will ignore it.
*/
#define ATTR_MAX_LINE_LENGTH 2048
/**
* The maximum size of the giattributes file. If the file exceeds this size we
* will ignore it.
*/
#define ATTR_MAX_FILE_SIZE (100 * 1024 * 1024)
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;
/*
* 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(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(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 */
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