| 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 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_check`:: |
| |
| This structure represents a set of attributes to check in a call |
| to `git_check_attr()` function, and receives the 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 |
| 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. |
| |
| |
| Querying Specific Attributes |
| ---------------------------- |
| |
| * 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_check_attr()` 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. |
| |
| |
| 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"); |
| check[1].attr = git_attr("ident"); |
| } |
| ------------ |
| |
| . Call `git_check_attr()` with the prepared array of `struct git_attr_check`: |
| |
| ------------ |
| const char *path; |
| |
| setup_check(); |
| git_check_attr(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 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 ...) { |
| ... |
| } |
| ------------ |
| |
| |
| Querying All Attributes |
| ----------------------- |
| |
| To get the values of all attributes associated with a file: |
| |
| * Call `git_all_attrs()`, which returns an array of `git_attr_check` |
| structures. |
| |
| * Iterate over the `git_attr_check` array to examine the attribute |
| names and values. The name of the attribute described by a |
| `git_attr_check` object can be retrieved via |
| `git_attr_name(check[i].attr)`. (Please note that no items will be |
| returned for unset attributes, so `ATTR_UNSET()` will return false |
| for all returned `git_array_check` objects.) |
| |
| * Free the `git_array_check` array. |