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gitattributes API
=================
gitattributes mechanism gives a uniform way to associate various
attributes to set of paths.
Data Structure
--------------
`struct git_attr`::
An attribute is an opaque object that is identified by its name.
Pass the name and its length 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.
`struct git_attr_check`::
This structure represents a set of attributes to check in a call
to `git_checkattr()` function, and receives the results.
Calling Sequence
----------------
* Prepare an array of `struct git_attr_check` to define the list of
attributes you would want to check. To populate this array, you would
need to define necessary attributes by calling `git_attr()` function.
* Call git_checkattr() to check the attributes for the path.
* Inspect `git_attr_check` structure to see how each of the attribute in
the array is defined for the path.
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
git_attr_check` records it. There are three macros to check these:
`ATTR_TRUE()`::
Returns true if the attribute is Set for the path.
`ATTR_FALSE()`::
Returns true if the attribute is Unset for the path.
`ATTR_UNSET()`::
Returns true if the attribute is Unspecified for the path.
If none of the above returns true, `.value` member points at a string
value of the attribute for the path.
Example
-------
To see how attributes "crlf" and "indent" are set for different paths.
. Prepare an array of `struct git_attr_check` with two elements (because
we are checking two attributes). Initialize their `attr` member with
pointers to `struct git_attr` obtained by calling `git_attr()`:
------------
static struct git_attr_check check[2];
static void setup_check(void)
{
if (check[0].attr)
return; /* already done */
check[0].attr = git_attr("crlf", 4);
check[1].attr = git_attr("ident", 5);
}
------------
. Call `git_checkattr()` with the prepared array of `struct git_attr_check`:
------------
const char *path;
setup_check();
git_checkattr(path, ARRAY_SIZE(check), check);
------------
. Act on `.value` member of the result, left in `check[]`:
------------
const char *value = check[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 not 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 ...) {
...
}
------------
(JC)
|
