include/git2/attr.h

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7 #ifndef INCLUDE_git_attr_h__
   8 #define INCLUDE_git_attr_h__
   9
  10 #include "common.h"
  11 #include "types.h"
  12
  13 /**
  14  * @file git2/attr.h
  15  * @brief Git attribute management routines
  16  * @defgroup git_attr Git attribute management routines
  17  * @ingroup Git
  18  * @{
  19  */
  20 GIT_BEGIN_DECL
  21
  22 /**
  23  * GIT_ATTR_TRUE checks if an attribute is set on.  In core git
  24  * parlance, this the value for "Set" attributes.
  25  *
  26  * For example, if the attribute file contains:
  27  *
  28  *    *.c foo
  29  *
  30  * Then for file `xyz.c` looking up attribute "foo" gives a value for
  31  * which `GIT_ATTR_TRUE(value)` is true.
  32  */
  33 #define GIT_ATTR_IS_TRUE(attr)  (git_attr_value(attr) == GIT_ATTR_VALUE_TRUE)
  34
  35 /**
  36  * GIT_ATTR_FALSE checks if an attribute is set off.  In core git
  37  * parlance, this is the value for attributes that are "Unset" (not to
  38  * be confused with values that a "Unspecified").
  39  *
  40  * For example, if the attribute file contains:
  41  *
  42  *    *.h -foo
  43  *
  44  * Then for file `zyx.h` looking up attribute "foo" gives a value for
  45  * which `GIT_ATTR_FALSE(value)` is true.
  46  */
  47 #define GIT_ATTR_IS_FALSE(attr) (git_attr_value(attr) == GIT_ATTR_VALUE_FALSE)
  48
  49 /**
  50  * GIT_ATTR_UNSPECIFIED checks if an attribute is unspecified.  This
  51  * may be due to the attribute not being mentioned at all or because
  52  * the attribute was explicitly set unspecified via the `!` operator.
  53  *
  54  * For example, if the attribute file contains:
  55  *
  56  *    *.c foo
  57  *    *.h -foo
  58  *    onefile.c !foo
  59  *
  60  * Then for `onefile.c` looking up attribute "foo" yields a value with
  61  * `GIT_ATTR_UNSPECIFIED(value)` of true.  Also, looking up "foo" on
  62  * file `onefile.rb` or looking up "bar" on any file will all give
  63  * `GIT_ATTR_UNSPECIFIED(value)` of true.
  64  */
  65 #define GIT_ATTR_IS_UNSPECIFIED(attr) (git_attr_value(attr) == GIT_ATTR_VALUE_UNSPECIFIED)
  66
  67 /**
  68  * GIT_ATTR_HAS_VALUE checks if an attribute is set to a value (as
  69  * opposed to TRUE, FALSE or UNSPECIFIED).  This would be the case if
  70  * for a file with something like:
  71  *
  72  *    *.txt eol=lf
  73  *
  74  * Given this, looking up "eol" for `onefile.txt` will give back the
  75  * string "lf" and `GIT_ATTR_SET_TO_VALUE(attr)` will return true.
  76  */
  77 #define GIT_ATTR_HAS_VALUE(attr) (git_attr_value(attr) == GIT_ATTR_VALUE_STRING)
  78
  79 /**
  80  * Possible states for an attribute
  81  */
  82 typedef enum {
  83         GIT_ATTR_VALUE_UNSPECIFIED = 0, /**< The attribute has been left unspecified */
  84         GIT_ATTR_VALUE_TRUE,   /**< The attribute has been set */
  85         GIT_ATTR_VALUE_FALSE,  /**< The attribute has been unset */
  86         GIT_ATTR_VALUE_STRING, /**< This attribute has a value */
  87 } git_attr_value_t;
  88
  89 /**
  90  * Return the value type for a given attribute.
  91  *
  92  * This can be either `TRUE`, `FALSE`, `UNSPECIFIED` (if the attribute
  93  * was not set at all), or `VALUE`, if the attribute was set to an
  94  * actual string.
  95  *
  96  * If the attribute has a `VALUE` string, it can be accessed normally
  97  * as a NULL-terminated C string.
  98  *
  99  * @param attr The attribute
 100  * @return the value type for the attribute
 101  */
 102 GIT_EXTERN(git_attr_value_t) git_attr_value(const char *attr);
 103
 104 /**
 105  * Check attribute flags: Reading values from index and working directory.
 106  *
 107  * When checking attributes, it is possible to check attribute files
 108  * in both the working directory (if there is one) and the index (if
 109  * there is one).  You can explicitly choose where to check and in
 110  * which order using the following flags.
 111  *
 112  * Core git usually checks the working directory then the index,
 113  * except during a checkout when it checks the index first.  It will
 114  * use index only for creating archives or for a bare repo (if an
 115  * index has been specified for the bare repo).
 116  */
 117 #define GIT_ATTR_CHECK_FILE_THEN_INDEX  0
 118 #define GIT_ATTR_CHECK_INDEX_THEN_FILE  1
 119 #define GIT_ATTR_CHECK_INDEX_ONLY               2
 120
 121 /**
 122  * Check attribute flags: controlling extended attribute behavior.
 123  *
 124  * Normally, attribute checks include looking in the /etc (or system
 125  * equivalent) directory for a `gitattributes` file.  Passing this
 126  * flag will cause attribute checks to ignore that file.
 127  * equivalent) directory for a `gitattributes` file.  Passing the
 128  * `GIT_ATTR_CHECK_NO_SYSTEM` flag will cause attribute checks to
 129  * ignore that file.
 130  *
 131  * Passing the `GIT_ATTR_CHECK_INCLUDE_HEAD` flag will use attributes
 132  * from a `.gitattributes` file in the repository at the HEAD revision.
 133  */
 134 #define GIT_ATTR_CHECK_NO_SYSTEM        (1 << 2)
 135 #define GIT_ATTR_CHECK_INCLUDE_HEAD     (1 << 3)
 136
 137 /**
 138  * Look up the value of one git attribute for path.
 139  *
 140  * @param value_out Output of the value of the attribute.  Use the GIT_ATTR_...
 141  *             macros to test for TRUE, FALSE, UNSPECIFIED, etc. or just
 142  *             use the string value for attributes set to a value.  You
 143  *             should NOT modify or free this value.
 144  * @param repo The repository containing the path.
 145  * @param flags A combination of GIT_ATTR_CHECK... flags.
 146  * @param path The path to check for attributes.  Relative paths are
 147  *             interpreted relative to the repo root.  The file does
 148  *             not have to exist, but if it does not, then it will be
 149  *             treated as a plain file (not a directory).
 150  * @param name The name of the attribute to look up.
 151  */
 152 GIT_EXTERN(int) git_attr_get(
 153         const char **value_out,
 154         git_repository *repo,
 155         uint32_t flags,
 156         const char *path,
 157         const char *name);
 158
 159 /**
 160  * Look up a list of git attributes for path.
 161  *
 162  * Use this if you have a known list of attributes that you want to
 163  * look up in a single call.  This is somewhat more efficient than
 164  * calling `git_attr_get()` multiple times.
 165  *
 166  * For example, you might write:
 167  *
 168  *     const char *attrs[] = { "crlf", "diff", "foo" };
 169  *     const char **values[3];
 170  *     git_attr_get_many(values, repo, 0, "my/fun/file.c", 3, attrs);
 171  *
 172  * Then you could loop through the 3 values to get the settings for
 173  * the three attributes you asked about.
 174  *
 175  * @param values_out An array of num_attr entries that will have string
 176  *             pointers written into it for the values of the attributes.
 177  *             You should not modify or free the values that are written
 178  *             into this array (although of course, you should free the
 179  *             array itself if you allocated it).
 180  * @param repo The repository containing the path.
 181  * @param flags A combination of GIT_ATTR_CHECK... flags.
 182  * @param path The path inside the repo to check attributes.  This
 183  *             does not have to exist, but if it does not, then
 184  *             it will be treated as a plain file (i.e. not a directory).
 185  * @param num_attr The number of attributes being looked up
 186  * @param names An array of num_attr strings containing attribute names.
 187  */
 188 GIT_EXTERN(int) git_attr_get_many(
 189         const char **values_out,
 190         git_repository *repo,
 191         uint32_t flags,
 192         const char *path,
 193         size_t num_attr,
 194         const char **names);
 195
 196 /**
 197  * The callback used with git_attr_foreach.
 198  *
 199  * This callback will be invoked only once per attribute name, even if there
 200  * are multiple rules for a given file. The highest priority rule will be
 201  * used.
 202  *
 203  * @see git_attr_foreach.
 204  *
 205  * @param name The attribute name.
 206  * @param value The attribute value. May be NULL if the attribute is explicitly
 207  *              set to UNSPECIFIED using the '!' sign.
 208  * @param payload A user-specified pointer.
 209  * @return 0 to continue looping, non-zero to stop. This value will be returned
 210  *         from git_attr_foreach.
 211  */
 212 typedef int GIT_CALLBACK(git_attr_foreach_cb)(const char *name, const char *value, void *payload);
 213
 214 /**
 215  * Loop over all the git attributes for a path.
 216  *
 217  * @param repo The repository containing the path.
 218  * @param flags A combination of GIT_ATTR_CHECK... flags.
 219  * @param path Path inside the repo to check attributes.  This does not have
 220  *             to exist, but if it does not, then it will be treated as a
 221  *             plain file (i.e. not a directory).
 222  * @param callback Function to invoke on each attribute name and value.
 223  *                 See git_attr_foreach_cb.
 224  * @param payload Passed on as extra parameter to callback function.
 225  * @return 0 on success, non-zero callback return value, or error code
 226  */
 227 GIT_EXTERN(int) git_attr_foreach(
 228         git_repository *repo,
 229         uint32_t flags,
 230         const char *path,
 231         git_attr_foreach_cb callback,
 232         void *payload);
 233
 234 /**
 235  * Flush the gitattributes cache.
 236  *
 237  * Call this if you have reason to believe that the attributes files on
 238  * disk no longer match the cached contents of memory.  This will cause
 239  * the attributes files to be reloaded the next time that an attribute
 240  * access function is called.
 241  *
 242  * @param repo The repository containing the gitattributes cache
 243  * @return 0 on success, or an error code
 244  */
 245 GIT_EXTERN(int) git_attr_cache_flush(
 246         git_repository *repo);
 247
 248 /**
 249  * Add a macro definition.
 250  *
 251  * Macros will automatically be loaded from the top level `.gitattributes`
 252  * file of the repository (plus the build-in "binary" macro).  This
 253  * function allows you to add others.  For example, to add the default
 254  * macro, you would call:
 255  *
 256  *     git_attr_add_macro(repo, "binary", "-diff -crlf");
 257  */
 258 GIT_EXTERN(int) git_attr_add_macro(
 259         git_repository *repo,
 260         const char *name,
 261         const char *values);
 262
 263 /** @} */
 264 GIT_END_DECL
 265 #endif
 266