userdiff.c

   1 #include "git-compat-util.h"
   2 #include "config.h"
   3 #include "userdiff.h"
   4 #include "attr.h"
   5 #include "strbuf.h"
   6
   7 static struct userdiff_driver *drivers;
   8 static int ndrivers;
   9 static int drivers_alloc;
  10
  11 #define PATTERNS(lang, rx, wrx) { \
  12         .name = lang, \
  13         .binary = -1, \
  14         .funcname = { \
  15                 .pattern = rx, \
  16                 .cflags = REG_EXTENDED, \
  17         }, \
  18         .word_regex = wrx "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+", \
  19         .word_regex_multi_byte = wrx "|[^[:space:]]", \
  20 }
  21 #define IPATTERN(lang, rx, wrx) { \
  22         .name = lang, \
  23         .binary = -1, \
  24         .funcname = { \
  25                 .pattern = rx, \
  26                 .cflags = REG_EXTENDED | REG_ICASE, \
  27         }, \
  28         .word_regex = wrx "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+", \
  29         .word_regex_multi_byte = wrx "|[^[:space:]]", \
  30 }
  31
  32 /*
  33  * Built-in drivers for various languages, sorted by their names
  34  * (except that the "default" is left at the end).
  35  *
  36  * When writing or updating patterns, assume that the contents these
  37  * patterns are applied to are syntactically correct.  The patterns
  38  * can be simple without implementing all syntactical corner cases, as
  39  * long as they are sufficiently permissive.
  40  */
  41 static struct userdiff_driver builtin_drivers[] = {
  42 IPATTERN("ada",
  43          "!^(.*[ \t])?(is[ \t]+new|renames|is[ \t]+separate)([ \t].*)?$\n"
  44          "!^[ \t]*with[ \t].*$\n"
  45          "^[ \t]*((procedure|function)[ \t]+.*)$\n"
  46          "^[ \t]*((package|protected|task)[ \t]+.*)$",
  47          /* -- */
  48          "[a-zA-Z][a-zA-Z0-9_]*"
  49          "|[-+]?[0-9][0-9#_.aAbBcCdDeEfF]*([eE][+-]?[0-9_]+)?"
  50          "|=>|\\.\\.|\\*\\*|:=|/=|>=|<=|<<|>>|<>"),
  51 PATTERNS("bash",
  52          /* Optional leading indentation */
  53          "^[ \t]*"
  54          /* Start of captured text */
  55          "("
  56          "("
  57              /* POSIX identifier with mandatory parentheses */
  58              "[a-zA-Z_][a-zA-Z0-9_]*[ \t]*\\([ \t]*\\))"
  59          "|"
  60              /* Bashism identifier with optional parentheses */
  61              "(function[ \t]+[a-zA-Z_][a-zA-Z0-9_]*(([ \t]*\\([ \t]*\\))|([ \t]+))"
  62          ")"
  63          /* Optional whitespace */
  64          "[ \t]*"
  65          /* Compound command starting with `{`, `(`, `((` or `[[` */
  66          "(\\{|\\(\\(?|\\[\\[)"
  67          /* End of captured text */
  68          ")",
  69          /* -- */
  70          /* Characters not in the default $IFS value */
  71          "[^ \t]+"),
  72 PATTERNS("bibtex",
  73          "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
  74          /* -- */
  75          "[={}\"]|[^={}\" \t]+"),
  76 PATTERNS("cpp",
  77          /* Jump targets or access declarations */
  78          "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])\n"
  79          /* functions/methods, variables, and compounds at top level */
  80          "^((::[[:space:]]*)?[A-Za-z_].*)$",
  81          /* -- */
  82          /* identifiers and keywords */
  83          "[a-zA-Z_][a-zA-Z0-9_]*"
  84          /* decimal and octal integers as well as floatingpoint numbers */
  85          "|[0-9][0-9.]*([Ee][-+]?[0-9]+)?[fFlLuU]*"
  86          /* hexadecimal and binary integers */
  87          "|0[xXbB][0-9a-fA-F]+[lLuU]*"
  88          /* floatingpoint numbers that begin with a decimal point */
  89          "|\\.[0-9][0-9]*([Ee][-+]?[0-9]+)?[fFlL]?"
  90          "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*|<=>"),
  91 PATTERNS("csharp",
  92          /* Keywords */
  93          "!^[ \t]*(do|while|for|if|else|instanceof|new|return|switch|case|throw|catch|using)\n"
  94          /* Methods and constructors */
  95          "^[ \t]*(((static|public|internal|private|protected|new|virtual|sealed|override|unsafe|async)[ \t]+)*[][<>@.~_[:alnum:]]+[ \t]+[<>@._[:alnum:]]+[ \t]*\\(.*\\))[ \t]*$\n"
  96          /* Properties */
  97          "^[ \t]*(((static|public|internal|private|protected|new|virtual|sealed|override|unsafe)[ \t]+)*[][<>@.~_[:alnum:]]+[ \t]+[@._[:alnum:]]+)[ \t]*$\n"
  98          /* Type definitions */
  99          "^[ \t]*(((static|public|internal|private|protected|new|unsafe|sealed|abstract|partial)[ \t]+)*(class|enum|interface|struct|record)[ \t]+.*)$\n"
 100          /* Namespace */
 101          "^[ \t]*(namespace[ \t]+.*)$",
 102          /* -- */
 103          "[a-zA-Z_][a-zA-Z0-9_]*"
 104          "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
 105          "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
 106 IPATTERN("css",
 107          "![:;][[:space:]]*$\n"
 108          "^[:[@.#]?[_a-z0-9].*$",
 109          /* -- */
 110          /*
 111           * This regex comes from W3C CSS specs. Should theoretically also
 112           * allow ISO 10646 characters U+00A0 and higher,
 113           * but they are not handled in this regex.
 114           */
 115          "-?[_a-zA-Z][-_a-zA-Z0-9]*" /* identifiers */
 116          "|-?[0-9]+|\\#[0-9a-fA-F]+" /* numbers */
 117 ),
 118 PATTERNS("dts",
 119          "!;\n"
 120          "!=\n"
 121          /* lines beginning with a word optionally preceded by '&' or the root */
 122          "^[ \t]*((/[ \t]*\\{|&?[a-zA-Z_]).*)",
 123          /* -- */
 124          /* Property names and math operators */
 125          "[a-zA-Z0-9,._+?#-]+"
 126          "|[-+*/%&^|!~]|>>|<<|&&|\\|\\|"),
 127 PATTERNS("elixir",
 128          "^[ \t]*((def(macro|module|impl|protocol|p)?|test)[ \t].*)$",
 129          /* -- */
 130          /* Atoms, names, and module attributes */
 131          "[@:]?[a-zA-Z0-9@_?!]+"
 132          /* Numbers with specific base */
 133          "|[-+]?0[xob][0-9a-fA-F]+"
 134          /* Numbers */
 135          "|[-+]?[0-9][0-9_.]*([eE][-+]?[0-9_]+)?"
 136          /* Operators and atoms that represent them */
 137          "|:?(\\+\\+|--|\\.\\.|~~~|<>|\\^\\^\\^|<?\\|>|<<<?|>?>>|<<?~|~>?>|<~>|<=|>=|===?|!==?|=~|&&&?|\\|\\|\\|?|=>|<-|\\\\\\\\|->)"
 138          /* Not real operators, but should be grouped */
 139          "|:?%[A-Za-z0-9_.]\\{\\}?"),
 140 IPATTERN("fortran",
 141          /* Don't match comment lines */
 142          "!^([C*]|[ \t]*!)\n"
 143          /* Don't match 'module procedure' lines */
 144          "!^[ \t]*MODULE[ \t]+PROCEDURE[ \t]\n"
 145          /* Program, module, block data */
 146          "^[ \t]*((END[ \t]+)?(PROGRAM|MODULE|BLOCK[ \t]+DATA"
 147                 /* Subroutines and functions */
 148                 "|([^!'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
 149          /* -- */
 150          "[a-zA-Z][a-zA-Z0-9_]*"
 151          "|\\.([Ee][Qq]|[Nn][Ee]|[Gg][TtEe]|[Ll][TtEe]|[Tt][Rr][Uu][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Aa][Nn][Dd]|[Oo][Rr]|[Nn]?[Ee][Qq][Vv]|[Nn][Oo][Tt])\\."
 152          /* numbers and format statements like 2E14.4, or ES12.6, 9X.
 153           * Don't worry about format statements without leading digits since
 154           * they would have been matched above as a variable anyway. */
 155          "|[-+]?[0-9.]+([AaIiDdEeFfLlTtXx][Ss]?[-+]?[0-9.]*)?(_[a-zA-Z0-9][a-zA-Z0-9_]*)?"
 156          "|//|\\*\\*|::|[/<>=]="),
 157 IPATTERN("fountain",
 158          "^((\\.[^.]|(int|ext|est|int\\.?/ext|i/e)[. ]).*)$",
 159          /* -- */
 160          "[^ \t-]+"),
 161 PATTERNS("golang",
 162          /* Functions */
 163          "^[ \t]*(func[ \t]*.*(\\{[ \t]*)?)\n"
 164          /* Structs and interfaces */
 165          "^[ \t]*(type[ \t].*(struct|interface)[ \t]*(\\{[ \t]*)?)",
 166          /* -- */
 167          "[a-zA-Z_][a-zA-Z0-9_]*"
 168          "|[-+0-9.eE]+i?|0[xX]?[0-9a-fA-F]+i?"
 169          "|[-+*/<>%&^|=!:]=|--|\\+\\+|<<=?|>>=?|&\\^=?|&&|\\|\\||<-|\\.{3}"),
 170 PATTERNS("html",
 171          "^[ \t]*(<[Hh][1-6]([ \t].*)?>.*)$",
 172          /* -- */
 173          "[^<>= \t]+"),
 174 PATTERNS("java",
 175          "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
 176          /* Class, enum, interface, and record declarations */
 177          "^[ \t]*(([a-z-]+[ \t]+)*(class|enum|interface|record)[ \t]+.*)$\n"
 178          /* Method definitions; note that constructor signatures are not */
 179          /* matched because they are indistinguishable from method calls. */
 180          "^[ \t]*(([A-Za-z_<>&][][?&<>.,A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
 181          /* -- */
 182          "[a-zA-Z_][a-zA-Z0-9_]*"
 183          "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
 184          "|[-+*/<>%&^|=!]="
 185          "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"),
 186 PATTERNS("kotlin",
 187          "^[ \t]*(([a-z]+[ \t]+)*(fun|class|interface)[ \t]+.*)$",
 188          /* -- */
 189          "[a-zA-Z_][a-zA-Z0-9_]*"
 190          /* hexadecimal and binary numbers */
 191          "|0[xXbB][0-9a-fA-F_]+[lLuU]*"
 192          /* integers and floats */
 193          "|[0-9][0-9_]*([.][0-9_]*)?([Ee][-+]?[0-9]+)?[fFlLuU]*"
 194          /* floating point numbers beginning with decimal point */
 195          "|[.][0-9][0-9_]*([Ee][-+]?[0-9]+)?[fFlLuU]?"
 196          /* unary and binary operators */
 197          "|[-+*/<>%&^|=!]==?|--|\\+\\+|<<=|>>=|&&|\\|\\||->|\\.\\*|!!|[?:.][.:]"),
 198 PATTERNS("markdown",
 199          "^ {0,3}#{1,6}[ \t].*",
 200          /* -- */
 201          "[^<>= \t]+"),
 202 PATTERNS("matlab",
 203          /*
 204           * Octave pattern is mostly the same as matlab, except that '%%%' and
 205           * '##' can also be used to begin code sections, in addition to '%%'
 206           * that is understood by both.
 207           */
 208          "^[[:space:]]*((classdef|function)[[:space:]].*)$|^(%%%?|##)[[:space:]].*$",
 209          /* -- */
 210          "[a-zA-Z_][a-zA-Z0-9_]*|[-+0-9.e]+|[=~<>]=|\\.[*/\\^']|\\|\\||&&"),
 211 PATTERNS("objc",
 212          /* Negate C statements that can look like functions */
 213          "!^[ \t]*(do|for|if|else|return|switch|while)\n"
 214          /* Objective-C methods */
 215          "^[ \t]*([-+][ \t]*\\([ \t]*[A-Za-z_][A-Za-z_0-9* \t]*\\)[ \t]*[A-Za-z_].*)$\n"
 216          /* C functions */
 217          "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$\n"
 218          /* Objective-C class/protocol definitions */
 219          "^(@(implementation|interface|protocol)[ \t].*)$",
 220          /* -- */
 221          "[a-zA-Z_][a-zA-Z0-9_]*"
 222          "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
 223          "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
 224 PATTERNS("pascal",
 225          "^(((class[ \t]+)?(procedure|function)|constructor|destructor|interface"
 226          "|implementation|initialization|finalization)[ \t]*.*)$\n"
 227          "^(.*=[ \t]*(class|record).*)$",
 228          /* -- */
 229          "[a-zA-Z_][a-zA-Z0-9_]*"
 230          "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
 231          "|<>|<=|>=|:=|\\.\\."),
 232 PATTERNS("perl",
 233          "^package .*\n"
 234          "^sub [[:alnum:]_':]+[ \t]*"
 235                 "(\\([^)]*\\)[ \t]*)?" /* prototype */
 236                 /*
 237                  * Attributes.  A regex can't count nested parentheses,
 238                  * so just slurp up whatever we see, taking care not
 239                  * to accept lines like "sub foo; # defined elsewhere".
 240                  *
 241                  * An attribute could contain a semicolon, but at that
 242                  * point it seems reasonable enough to give up.
 243                  */
 244                 "(:[^;#]*)?"
 245                 "(\\{[ \t]*)?" /* brace can come here or on the next line */
 246                 "(#.*)?$\n" /* comment */
 247          "^(BEGIN|END|INIT|CHECK|UNITCHECK|AUTOLOAD|DESTROY)[ \t]*"
 248                 "(\\{[ \t]*)?" /* brace can come here or on the next line */
 249                 "(#.*)?$\n"
 250          "^=head[0-9] .*",      /* POD */
 251          /* -- */
 252          "[[:alpha:]_'][[:alnum:]_']*"
 253          "|0[xb]?[0-9a-fA-F_]*"
 254          /* taking care not to interpret 3..5 as (3.)(.5) */
 255          "|[0-9a-fA-F_]+(\\.[0-9a-fA-F_]+)?([eE][-+]?[0-9_]+)?"
 256          "|=>|-[rwxoRWXOezsfdlpSugkbctTBMAC>]|~~|::"
 257          "|&&=|\\|\\|=|//=|\\*\\*="
 258          "|&&|\\|\\||//|\\+\\+|--|\\*\\*|\\.\\.\\.?"
 259          "|[-+*/%.^&<>=!|]="
 260          "|=~|!~"
 261          "|<<|<>|<=>|>>"),
 262 PATTERNS("php",
 263          "^[\t ]*(((public|protected|private|static|abstract|final)[\t ]+)*function.*)$\n"
 264          "^[\t ]*((((final|abstract)[\t ]+)?class|enum|interface|trait).*)$",
 265          /* -- */
 266          "[a-zA-Z_][a-zA-Z0-9_]*"
 267          "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
 268          "|[-+*/<>%&^|=!.]=|--|\\+\\+|<<=?|>>=?|===|&&|\\|\\||::|->"),
 269 PATTERNS("python",
 270          "^[ \t]*((class|(async[ \t]+)?def)[ \t].*)$",
 271          /* -- */
 272          "[a-zA-Z_][a-zA-Z0-9_]*"
 273          "|[-+0-9.e]+[jJlL]?|0[xX]?[0-9a-fA-F]+[lL]?"
 274          "|[-+*/<>%&^|=!]=|//=?|<<=?|>>=?|\\*\\*=?"),
 275          /* -- */
 276 PATTERNS("ruby",
 277          "^[ \t]*((class|module|def)[ \t].*)$",
 278          /* -- */
 279          "(@|@@|\\$)?[a-zA-Z_][a-zA-Z0-9_]*"
 280          "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+|\\?(\\\\C-)?(\\\\M-)?."
 281          "|//=?|[-+*/<>%&^|=!]=|<<=?|>>=?|===|\\.{1,3}|::|[!=]~"),
 282 PATTERNS("rust",
 283          "^[\t ]*((pub(\\([^\\)]+\\))?[\t ]+)?((async|const|unsafe|extern([\t ]+\"[^\"]+\"))[\t ]+)?(struct|enum|union|mod|trait|fn|impl|macro_rules!)[< \t]+[^;]*)$",
 284          /* -- */
 285          "[a-zA-Z_][a-zA-Z0-9_]*"
 286          "|[0-9][0-9_a-fA-Fiosuxz]*(\\.([0-9]*[eE][+-]?)?[0-9_fF]*)?"
 287          "|[-+*\\/<>%&^|=!:]=|<<=?|>>=?|&&|\\|\\||->|=>|\\.{2}=|\\.{3}|::"),
 288 PATTERNS("scheme",
 289          "^[\t ]*(\\(((define|def(struct|syntax|class|method|rules|record|proto|alias)?)[-*/ \t]|(library|module|struct|class)[*+ \t]).*)$",
 290          /*
 291           * R7RS valid identifiers include any sequence enclosed
 292           * within vertical lines having no backslashes
 293           */
 294          "\\|([^\\\\]*)\\|"
 295          /* All other words should be delimited by spaces or parentheses */
 296          "|([^][)(}{[ \t])+"),
 297 PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
 298          "\\\\[a-zA-Z@]+|\\\\.|([a-zA-Z0-9]|[^\x01-\x7f])+"),
 299 { "default", NULL, NULL, -1, { NULL, 0 } },
 300 };
 301 #undef PATTERNS
 302 #undef IPATTERN
 303
 304 static struct userdiff_driver driver_true = {
 305         .name = "diff=true",
 306         .binary = 0,
 307 };
 308
 309 static struct userdiff_driver driver_false = {
 310         .name = "!diff",
 311         .binary = 1,
 312 };
 313
 314 struct find_by_namelen_data {
 315         const char *name;
 316         size_t len;
 317         struct userdiff_driver *driver;
 318 };
 319
 320 static int userdiff_find_by_namelen_cb(struct userdiff_driver *driver,
 321                                        enum userdiff_driver_type type UNUSED,
 322                                        void *priv)
 323 {
 324         struct find_by_namelen_data *cb_data = priv;
 325
 326         if (!strncmp(driver->name, cb_data->name, cb_data->len) &&
 327             !driver->name[cb_data->len]) {
 328                 cb_data->driver = driver;
 329                 return 1; /* tell the caller to stop iterating */
 330         }
 331         return 0;
 332 }
 333
 334 static int regexec_supports_multi_byte_chars(void)
 335 {
 336         static const char not_space[] = "[^[:space:]]";
 337         static const char utf8_multi_byte_char[] = "\xc2\xa3";
 338         regex_t re;
 339         regmatch_t match;
 340         static int result = -1;
 341
 342         if (result != -1)
 343                 return result;
 344         if (regcomp(&re, not_space, REG_EXTENDED))
 345                 BUG("invalid regular expression: %s", not_space);
 346         result = !regexec(&re, utf8_multi_byte_char, 1, &match, 0) &&
 347                 match.rm_so == 0 &&
 348                 match.rm_eo == strlen(utf8_multi_byte_char);
 349         regfree(&re);
 350         return result;
 351 }
 352
 353 static struct userdiff_driver *userdiff_find_by_namelen(const char *name, size_t len)
 354 {
 355         struct find_by_namelen_data udcbdata = {
 356                 .name = name,
 357                 .len = len,
 358         };
 359         for_each_userdiff_driver(userdiff_find_by_namelen_cb, &udcbdata);
 360         return udcbdata.driver;
 361 }
 362
 363 static int parse_funcname(struct userdiff_funcname *f, const char *k,
 364                 const char *v, int cflags)
 365 {
 366         if (git_config_string(&f->pattern, k, v) < 0)
 367                 return -1;
 368         f->cflags = cflags;
 369         return 0;
 370 }
 371
 372 static int parse_tristate(int *b, const char *k, const char *v)
 373 {
 374         if (v && !strcasecmp(v, "auto"))
 375                 *b = -1;
 376         else
 377                 *b = git_config_bool(k, v);
 378         return 0;
 379 }
 380
 381 static int parse_bool(int *b, const char *k, const char *v)
 382 {
 383         *b = git_config_bool(k, v);
 384         return 0;
 385 }
 386
 387 int userdiff_config(const char *k, const char *v)
 388 {
 389         struct userdiff_driver *drv;
 390         const char *name, *type;
 391         size_t namelen;
 392
 393         if (parse_config_key(k, "diff", &name, &namelen, &type) || !name)
 394                 return 0;
 395
 396         drv = userdiff_find_by_namelen(name, namelen);
 397         if (!drv) {
 398                 ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
 399                 drv = &drivers[ndrivers++];
 400                 memset(drv, 0, sizeof(*drv));
 401                 drv->name = xmemdupz(name, namelen);
 402                 drv->binary = -1;
 403         }
 404
 405         if (!strcmp(type, "funcname"))
 406                 return parse_funcname(&drv->funcname, k, v, 0);
 407         if (!strcmp(type, "xfuncname"))
 408                 return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
 409         if (!strcmp(type, "binary"))
 410                 return parse_tristate(&drv->binary, k, v);
 411         if (!strcmp(type, "command"))
 412                 return git_config_string(&drv->external, k, v);
 413         if (!strcmp(type, "textconv"))
 414                 return git_config_string(&drv->textconv, k, v);
 415         if (!strcmp(type, "cachetextconv"))
 416                 return parse_bool(&drv->textconv_want_cache, k, v);
 417         if (!strcmp(type, "wordregex"))
 418                 return git_config_string(&drv->word_regex, k, v);
 419         if (!strcmp(type, "algorithm"))
 420                 return git_config_string(&drv->algorithm, k, v);
 421
 422         return 0;
 423 }
 424
 425 struct userdiff_driver *userdiff_find_by_name(const char *name)
 426 {
 427         int len = strlen(name);
 428         struct userdiff_driver *driver = userdiff_find_by_namelen(name, len);
 429         if (driver && driver->word_regex_multi_byte) {
 430                 if (regexec_supports_multi_byte_chars())
 431                         driver->word_regex = driver->word_regex_multi_byte;
 432                 driver->word_regex_multi_byte = NULL;
 433         }
 434         return driver;
 435 }
 436
 437 struct userdiff_driver *userdiff_find_by_path(struct index_state *istate,
 438                                               const char *path)
 439 {
 440         static struct attr_check *check;
 441
 442         if (!check)
 443                 check = attr_check_initl("diff", NULL);
 444         if (!path)
 445                 return NULL;
 446         git_check_attr(istate, path, check);
 447
 448         if (ATTR_TRUE(check->items[0].value))
 449                 return &driver_true;
 450         if (ATTR_FALSE(check->items[0].value))
 451                 return &driver_false;
 452         if (ATTR_UNSET(check->items[0].value))
 453                 return NULL;
 454         return userdiff_find_by_name(check->items[0].value);
 455 }
 456
 457 struct userdiff_driver *userdiff_get_textconv(struct repository *r,
 458                                               struct userdiff_driver *driver)
 459 {
 460         if (!driver->textconv)
 461                 return NULL;
 462
 463         if (driver->textconv_want_cache && !driver->textconv_cache) {
 464                 struct notes_cache *c = xmalloc(sizeof(*c));
 465                 struct strbuf name = STRBUF_INIT;
 466
 467                 strbuf_addf(&name, "textconv/%s", driver->name);
 468                 notes_cache_init(r, c, name.buf, driver->textconv);
 469                 driver->textconv_cache = c;
 470                 strbuf_release(&name);
 471         }
 472
 473         return driver;
 474 }
 475
 476 static int for_each_userdiff_driver_list(each_userdiff_driver_fn fn,
 477                                          enum userdiff_driver_type type, void *cb_data,
 478                                          struct userdiff_driver *drv,
 479                                          int drv_size)
 480 {
 481         int i;
 482         int ret;
 483         for (i = 0; i < drv_size; i++) {
 484                 struct userdiff_driver *item = drv + i;
 485                 if ((ret = fn(item, type, cb_data)))
 486                         return ret;
 487         }
 488         return 0;
 489 }
 490
 491 int for_each_userdiff_driver(each_userdiff_driver_fn fn, void *cb_data)
 492 {
 493         int ret;
 494
 495         ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_CUSTOM,
 496                                             cb_data, drivers, ndrivers);
 497         if (ret)
 498                 return ret;
 499
 500         ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_BUILTIN,
 501                                             cb_data, builtin_drivers,
 502                                             ARRAY_SIZE(builtin_drivers));
 503         if (ret)
 504                 return ret;
 505
 506         return 0;
 507 }