d932f4eb9f
Suggested by: Junio Hamano <gitster@pobox.com> Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
129 lines
3.6 KiB
Plaintext
129 lines
3.6 KiB
Plaintext
gitattributes API
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=================
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gitattributes mechanism gives a uniform way to associate various
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attributes to set of paths.
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Data Structure
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--------------
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`struct git_attr`::
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An attribute is an opaque object that is identified by its name.
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Pass the name to `git_attr()` function to obtain the object of
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this type. The internal representation of this structure is
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of no interest to the calling programs. The name of the
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attribute can be retrieved by calling `git_attr_name()`.
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`struct git_attr_check`::
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This structure represents a set of attributes to check in a call
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to `git_check_attr()` function, and receives the results.
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Attribute Values
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----------------
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An attribute for a path can be in one of four states: Set, Unset,
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Unspecified or set to a string, and `.value` member of `struct
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git_attr_check` records it. There are three macros to check these:
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`ATTR_TRUE()`::
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Returns true if the attribute is Set for the path.
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`ATTR_FALSE()`::
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Returns true if the attribute is Unset for the path.
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`ATTR_UNSET()`::
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Returns true if the attribute is Unspecified for the path.
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If none of the above returns true, `.value` member points at a string
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value of the attribute for the path.
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Querying Specific Attributes
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----------------------------
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* Prepare an array of `struct git_attr_check` to define the list of
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attributes you would want to check. To populate this array, you would
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need to define necessary attributes by calling `git_attr()` function.
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* Call `git_check_attr()` to check the attributes for the path.
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* Inspect `git_attr_check` structure to see how each of the attribute in
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the array is defined for the path.
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Example
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-------
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To see how attributes "crlf" and "indent" are set for different paths.
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. Prepare an array of `struct git_attr_check` with two elements (because
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we are checking two attributes). Initialize their `attr` member with
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pointers to `struct git_attr` obtained by calling `git_attr()`:
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------------
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static struct git_attr_check check[2];
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static void setup_check(void)
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{
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if (check[0].attr)
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return; /* already done */
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check[0].attr = git_attr("crlf");
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check[1].attr = git_attr("ident");
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}
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------------
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. Call `git_check_attr()` with the prepared array of `struct git_attr_check`:
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------------
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const char *path;
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setup_check();
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git_check_attr(path, ARRAY_SIZE(check), check);
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------------
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. Act on `.value` member of the result, left in `check[]`:
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------------
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const char *value = check[0].value;
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if (ATTR_TRUE(value)) {
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The attribute is Set, by listing only the name of the
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attribute in the gitattributes file for the path.
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} else if (ATTR_FALSE(value)) {
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The attribute is Unset, by listing the name of the
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attribute prefixed with a dash - for the path.
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} else if (ATTR_UNSET(value)) {
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The attribute is not set nor unset for the path.
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} else if (!strcmp(value, "input")) {
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If none of ATTR_TRUE(), ATTR_FALSE(), or ATTR_UNSET() is
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true, the value is a string set in the gitattributes
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file for the path by saying "attr=value".
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} else if (... other check using value as string ...) {
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...
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}
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------------
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Querying All Attributes
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-----------------------
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To get the values of all attributes associated with a file:
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* Call `git_all_attrs()`, which returns an array of `git_attr_check`
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structures.
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* Iterate over the `git_attr_check` array to examine the attribute
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names and values. The name of the attribute described by a
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`git_attr_check` object can be retrieved via
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`git_attr_name(check[i].attr)`. (Please note that no items will be
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returned for unset attributes, so `ATTR_UNSET()` will return false
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for all returned `git_array_check` objects.)
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* Free the `git_array_check` array.
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