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[git.git] / attr.h
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1 #ifndef ATTR_H
2 #define ATTR_H
4 /**
5 * gitattributes mechanism gives a uniform way to associate various attributes
6 * to set of paths.
9 * Querying Specific Attributes
10 * ----------------------------
12 * - Prepare `struct attr_check` using attr_check_initl() function, enumerating
13 * the names of attributes whose values you are interested in, terminated with
14 * a NULL pointer. Alternatively, an empty `struct attr_check` can be
15 * prepared by calling `attr_check_alloc()` function and then attributes you
16 * want to ask about can be added to it with `attr_check_append()` function.
18 * - Call `git_check_attr()` to check the attributes for the path.
20 * - Inspect `attr_check` structure to see how each of the attribute in the
21 * array is defined for the path.
24 * Example
25 * -------
27 * To see how attributes "crlf" and "ident" are set for different paths.
29 * - Prepare a `struct attr_check` with two elements (because we are checking
30 * two attributes):
32 * ------------
33 * static struct attr_check *check;
34 * static void setup_check(void)
35 * {
36 * if (check)
37 * return; // already done
38 * check = attr_check_initl("crlf", "ident", NULL);
39 * }
40 * ------------
42 * - Call `git_check_attr()` with the prepared `struct attr_check`:
44 * ------------
45 * const char *path;
47 * setup_check();
48 * git_check_attr(path, check);
49 * ------------
51 * - Act on `.value` member of the result, left in `check->items[]`:
53 * ------------
54 * const char *value = check->items[0].value;
56 * if (ATTR_TRUE(value)) {
57 * The attribute is Set, by listing only the name of the
58 * attribute in the gitattributes file for the path.
59 * } else if (ATTR_FALSE(value)) {
60 * The attribute is Unset, by listing the name of the
61 * attribute prefixed with a dash - for the path.
62 * } else if (ATTR_UNSET(value)) {
63 * The attribute is neither set nor unset for the path.
64 * } else if (!strcmp(value, "input")) {
65 * If none of ATTR_TRUE(), ATTR_FALSE(), or ATTR_UNSET() is
66 * true, the value is a string set in the gitattributes
67 * file for the path by saying "attr=value".
68 * } else if (... other check using value as string ...) {
69 * ...
70 * }
71 * ------------
73 * To see how attributes in argv[] are set for different paths, only
74 * the first step in the above would be different.
76 * ------------
77 * static struct attr_check *check;
78 * static void setup_check(const char **argv)
79 * {
80 * check = attr_check_alloc();
81 * while (*argv) {
82 * struct git_attr *attr = git_attr(*argv);
83 * attr_check_append(check, attr);
84 * argv++;
85 * }
86 * }
87 * ------------
90 * Querying All Attributes
91 * -----------------------
93 * To get the values of all attributes associated with a file:
95 * - Prepare an empty `attr_check` structure by calling `attr_check_alloc()`.
97 * - Call `git_all_attrs()`, which populates the `attr_check` with the
98 * attributes attached to the path.
100 * - Iterate over the `attr_check.items[]` array to examine the attribute
101 * names and values. The name of the attribute described by an
102 * `attr_check.items[]` object can be retrieved via
103 * `git_attr_name(check->items[i].attr)`. (Please note that no items will be
104 * returned for unset attributes, so `ATTR_UNSET()` will return false for all
105 * returned `attr_check.items[]` objects.)
107 * - Free the `attr_check` struct by calling `attr_check_free()`.
110 struct index_state;
113 * An attribute is an opaque object that is identified by its name. Pass the
114 * name to `git_attr()` function to obtain the object of this type.
115 * The internal representation of this structure is of no interest to the
116 * calling programs. The name of the attribute can be retrieved by calling
117 * `git_attr_name()`.
119 struct git_attr;
121 /* opaque structures used internally for attribute collection */
122 struct all_attrs_item;
123 struct attr_stack;
124 struct index_state;
127 * Given a string, return the gitattribute object that
128 * corresponds to it.
130 const struct git_attr *git_attr(const char *);
132 /* Internal use */
133 extern const char git_attr__true[];
134 extern const char git_attr__false[];
137 * Attribute Values
138 * ----------------
140 * An attribute for a path can be in one of four states: Set, Unset, Unspecified
141 * or set to a string, and `.value` member of `struct attr_check_item` records
142 * it. The three macros check these, if none of them returns true, `.value`
143 * member points at a string value of the attribute for the path.
146 /* Returns true if the attribute is Set for the path. */
147 #define ATTR_TRUE(v) ((v) == git_attr__true)
149 /* Returns true if the attribute is Unset for the path. */
150 #define ATTR_FALSE(v) ((v) == git_attr__false)
152 /* Returns true if the attribute is Unspecified for the path. */
153 #define ATTR_UNSET(v) ((v) == NULL)
155 /* This structure represents one attribute and its value. */
156 struct attr_check_item {
157 const struct git_attr *attr;
158 const char *value;
162 * This structure represents a collection of `attr_check_item`. It is passed to
163 * `git_check_attr()` function, specifying the attributes to check, and
164 * receives their values.
166 struct attr_check {
167 int nr;
168 int alloc;
169 struct attr_check_item *items;
170 int all_attrs_nr;
171 struct all_attrs_item *all_attrs;
172 struct attr_stack *stack;
175 struct attr_check *attr_check_alloc(void);
176 struct attr_check *attr_check_initl(const char *, ...);
177 struct attr_check *attr_check_dup(const struct attr_check *check);
179 struct attr_check_item *attr_check_append(struct attr_check *check,
180 const struct git_attr *attr);
182 void attr_check_reset(struct attr_check *check);
183 void attr_check_clear(struct attr_check *check);
184 void attr_check_free(struct attr_check *check);
187 * Return the name of the attribute represented by the argument. The
188 * return value is a pointer to a null-delimited string that is part
189 * of the internal data structure; it should not be modified or freed.
191 const char *git_attr_name(const struct git_attr *);
193 void git_check_attr(const struct index_state *istate,
194 const char *path, struct attr_check *check);
197 * Retrieve all attributes that apply to the specified path.
198 * check holds the attributes and their values.
200 void git_all_attrs(const struct index_state *istate,
201 const char *path, struct attr_check *check);
203 enum git_attr_direction {
204 GIT_ATTR_CHECKIN,
205 GIT_ATTR_CHECKOUT,
206 GIT_ATTR_INDEX
208 void git_attr_set_direction(enum git_attr_direction new_direction);
210 void attr_start(void);
212 #endif /* ATTR_H */