/*
 * Copyright (C) the libgit2 contributors. All rights reserved.
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */
#ifndef INCLUDE_git_attr_h__
#define INCLUDE_git_attr_h__

#include "common.h"
#include "types.h"

/**
 * @file git2/attr.h
 * @brief Git attribute management routines
 * @defgroup git_attr Git attribute management routines
 * @ingroup Git
 * @{
 */
GIT_BEGIN_DECL

/**
 * GIT_ATTR_TRUE checks if an attribute is set on.  In core git
 * parlance, this the value for "Set" attributes.
 *
 * For example, if the attribute file contains:
 *
 *    *.c foo
 *
 * Then for file `xyz.c` looking up attribute "foo" gives a value for
 * which `GIT_ATTR_TRUE(value)` is true.
 */
#define GIT_ATTR_IS_TRUE(attr)	(git_attr_value(attr) == GIT_ATTR_VALUE_TRUE)

/**
 * GIT_ATTR_FALSE checks if an attribute is set off.  In core git
 * parlance, this is the value for attributes that are "Unset" (not to
 * be confused with values that a "Unspecified").
 *
 * For example, if the attribute file contains:
 *
 *    *.h -foo
 *
 * Then for file `zyx.h` looking up attribute "foo" gives a value for
 * which `GIT_ATTR_FALSE(value)` is true.
 */
#define GIT_ATTR_IS_FALSE(attr) (git_attr_value(attr) == GIT_ATTR_VALUE_FALSE)

/**
 * GIT_ATTR_UNSPECIFIED checks if an attribute is unspecified.  This
 * may be due to the attribute not being mentioned at all or because
 * the attribute was explicitly set unspecified via the `!` operator.
 *
 * For example, if the attribute file contains:
 *
 *    *.c foo
 *    *.h -foo
 *    onefile.c !foo
 *
 * Then for `onefile.c` looking up attribute "foo" yields a value with
 * `GIT_ATTR_UNSPECIFIED(value)` of true.  Also, looking up "foo" on
 * file `onefile.rb` or looking up "bar" on any file will all give
 * `GIT_ATTR_UNSPECIFIED(value)` of true.
 */
#define GIT_ATTR_IS_UNSPECIFIED(attr) (git_attr_value(attr) == GIT_ATTR_VALUE_UNSPECIFIED)

/**
 * GIT_ATTR_HAS_VALUE checks if an attribute is set to a value (as
 * opposed to TRUE, FALSE or UNSPECIFIED).  This would be the case if
 * for a file with something like:
 *
 *    *.txt eol=lf
 *
 * Given this, looking up "eol" for `onefile.txt` will give back the
 * string "lf" and `GIT_ATTR_SET_TO_VALUE(attr)` will return true.
 */
#define GIT_ATTR_HAS_VALUE(attr) (git_attr_value(attr) == GIT_ATTR_VALUE_STRING)

/**
 * Possible states for an attribute
 */
typedef enum {
	GIT_ATTR_VALUE_UNSPECIFIED = 0, /**< The attribute has been left unspecified */
	GIT_ATTR_VALUE_TRUE,   /**< The attribute has been set */
	GIT_ATTR_VALUE_FALSE,  /**< The attribute has been unset */
	GIT_ATTR_VALUE_STRING, /**< This attribute has a value */
} git_attr_value_t;

/**
 * Return the value type for a given attribute.
 *
 * This can be either `TRUE`, `FALSE`, `UNSPECIFIED` (if the attribute
 * was not set at all), or `VALUE`, if the attribute was set to an
 * actual string.
 *
 * If the attribute has a `VALUE` string, it can be accessed normally
 * as a NULL-terminated C string.
 *
 * @param attr The attribute
 * @return the value type for the attribute
 */
GIT_EXTERN(git_attr_value_t) git_attr_value(const char *attr);

/**
 * Check attribute flags: Reading values from index and working directory.
 *
 * When checking attributes, it is possible to check attribute files
 * in both the working directory (if there is one) and the index (if
 * there is one).  You can explicitly choose where to check and in
 * which order using the following flags.
 *
 * Core git usually checks the working directory then the index,
 * except during a checkout when it checks the index first.  It will
 * use index only for creating archives or for a bare repo (if an
 * index has been specified for the bare repo).
 */
#define GIT_ATTR_CHECK_FILE_THEN_INDEX	0
#define GIT_ATTR_CHECK_INDEX_THEN_FILE	1
#define GIT_ATTR_CHECK_INDEX_ONLY		2

/**
 * Check attribute flags: controlling extended attribute behavior.
 *
 * Normally, attribute checks include looking in the /etc (or system
 * equivalent) directory for a `gitattributes` file.  Passing this
 * flag will cause attribute checks to ignore that file.
 * equivalent) directory for a `gitattributes` file.  Passing the
 * `GIT_ATTR_CHECK_NO_SYSTEM` flag will cause attribute checks to
 * ignore that file.
 *
 * Passing the `GIT_ATTR_CHECK_INCLUDE_HEAD` flag will use attributes
 * from a `.gitattributes` file in the repository at the HEAD revision.
 */
#define GIT_ATTR_CHECK_NO_SYSTEM        (1 << 2)
#define GIT_ATTR_CHECK_INCLUDE_HEAD     (1 << 3)

/**
 * Look up the value of one git attribute for path.
 *
 * @param value_out Output of the value of the attribute.  Use the GIT_ATTR_...
 *             macros to test for TRUE, FALSE, UNSPECIFIED, etc. or just
 *             use the string value for attributes set to a value.  You
 *             should NOT modify or free this value.
 * @param repo The repository containing the path.
 * @param flags A combination of GIT_ATTR_CHECK... flags.
 * @param path The path to check for attributes.  Relative paths are
 *             interpreted relative to the repo root.  The file does
 *             not have to exist, but if it does not, then it will be
 *             treated as a plain file (not a directory).
 * @param name The name of the attribute to look up.
 */
GIT_EXTERN(int) git_attr_get(
	const char **value_out,
	git_repository *repo,
	uint32_t flags,
	const char *path,
	const char *name);

/**
 * Look up a list of git attributes for path.
 *
 * Use this if you have a known list of attributes that you want to
 * look up in a single call.  This is somewhat more efficient than
 * calling `git_attr_get()` multiple times.
 *
 * For example, you might write:
 *
 *     const char *attrs[] = { "crlf", "diff", "foo" };
 *     const char **values[3];
 *     git_attr_get_many(values, repo, 0, "my/fun/file.c", 3, attrs);
 *
 * Then you could loop through the 3 values to get the settings for
 * the three attributes you asked about.
 *
 * @param values_out An array of num_attr entries that will have string
 *             pointers written into it for the values of the attributes.
 *             You should not modify or free the values that are written
 *             into this array (although of course, you should free the
 *             array itself if you allocated it).
 * @param repo The repository containing the path.
 * @param flags A combination of GIT_ATTR_CHECK... flags.
 * @param path The path inside the repo to check attributes.  This
 *             does not have to exist, but if it does not, then
 *             it will be treated as a plain file (i.e. not a directory).
 * @param num_attr The number of attributes being looked up
 * @param names An array of num_attr strings containing attribute names.
 */
GIT_EXTERN(int) git_attr_get_many(
	const char **values_out,
	git_repository *repo,
	uint32_t flags,
	const char *path,
	size_t num_attr,
	const char **names);

/**
 * The callback used with git_attr_foreach.
 *
 * This callback will be invoked only once per attribute name, even if there
 * are multiple rules for a given file. The highest priority rule will be
 * used.
 *
 * @see git_attr_foreach.
 *
 * @param name The attribute name.
 * @param value The attribute value. May be NULL if the attribute is explicitly
 *              set to UNSPECIFIED using the '!' sign.
 * @param payload A user-specified pointer.
 * @return 0 to continue looping, non-zero to stop. This value will be returned
 *         from git_attr_foreach.
 */
typedef int GIT_CALLBACK(git_attr_foreach_cb)(const char *name, const char *value, void *payload);

/**
 * Loop over all the git attributes for a path.
 *
 * @param repo The repository containing the path.
 * @param flags A combination of GIT_ATTR_CHECK... flags.
 * @param path Path inside the repo to check attributes.  This does not have
 *             to exist, but if it does not, then it will be treated as a
 *             plain file (i.e. not a directory).
 * @param callback Function to invoke on each attribute name and value.
 *                 See git_attr_foreach_cb.
 * @param payload Passed on as extra parameter to callback function.
 * @return 0 on success, non-zero callback return value, or error code
 */
GIT_EXTERN(int) git_attr_foreach(
	git_repository *repo,
	uint32_t flags,
	const char *path,
	git_attr_foreach_cb callback,
	void *payload);

/**
 * Flush the gitattributes cache.
 *
 * Call this if you have reason to believe that the attributes files on
 * disk no longer match the cached contents of memory.  This will cause
 * the attributes files to be reloaded the next time that an attribute
 * access function is called.
 */
GIT_EXTERN(void) git_attr_cache_flush(
	git_repository *repo);

/**
 * Add a macro definition.
 *
 * Macros will automatically be loaded from the top level `.gitattributes`
 * file of the repository (plus the build-in "binary" macro).  This
 * function allows you to add others.  For example, to add the default
 * macro, you would call:
 *
 *     git_attr_add_macro(repo, "binary", "-diff -crlf");
 */
GIT_EXTERN(int) git_attr_add_macro(
	git_repository *repo,
	const char *name,
	const char *values);

/** @} */
GIT_END_DECL
#endif