 a58088abe2
			
		
	
	a58088abe2
	
	
	
		
			
			Signed-off-by: Justin Lebar <jlebar@google.com> 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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| 
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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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| 
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| 
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| Data Structure
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| --------------
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| 
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| `struct git_attr`::
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| 
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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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| 
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| `struct git_attr_check`::
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| 
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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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| 
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| 
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| Attribute Values
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| ----------------
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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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| 
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| `ATTR_TRUE()`::
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| 
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| 	Returns true if the attribute is Set for the path.
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| 
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| `ATTR_FALSE()`::
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| 
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| 	Returns true if the attribute is Unset for the path.
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| 
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| `ATTR_UNSET()`::
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| 
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| 	Returns true if the attribute is Unspecified for the path.
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| 
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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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| 
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| 
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| Querying Specific Attributes
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| ----------------------------
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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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| 
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| * Call `git_check_attr()` to check the attributes for the path.
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| 
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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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| 
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| 
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| Example
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| -------
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| 
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| To see how attributes "crlf" and "indent" are set for different paths.
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| 
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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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| ------------
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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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| 
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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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| ------------
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| 	const char *path;
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| 
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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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| 
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| . Act on `.value` member of the result, left in `check[]`:
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| 
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| ------------
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| 	const char *value = check[0].value;
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| 
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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 neither 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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| 
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| 
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| Querying All Attributes
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| -----------------------
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| 
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| To get the values of all attributes associated with a file:
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| 
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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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| 
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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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| 
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| * Free the `git_array_check` array.
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