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 #include "environment.h"
   7
   8 static struct userdiff_driver *drivers;
   9 static int ndrivers;
  10 static int drivers_alloc;
  11
  12 #define PATTERNS(lang, rx, wrx) { \
  13         .name = lang, \
  14         .binary = -1, \
  15         .funcname = { \
  16                 .pattern = rx, \
  17                 .cflags = REG_EXTENDED, \
  18         }, \
  19         .word_regex = wrx "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+", \
  20         .word_regex_multi_byte = wrx "|[^[:space:]]", \
  21 }
  22 #define IPATTERN(lang, rx, wrx) { \
  23         .name = lang, \
  24         .binary = -1, \
  25         .funcname = { \
  26                 .pattern = rx, \
  27                 .cflags = REG_EXTENDED | REG_ICASE, \
  28         }, \
  29         .word_regex = wrx "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+", \
  30         .word_regex_multi_byte = wrx "|[^[:space:]]", \
  31 }
  32
  33 /*
  34  * Built-in drivers for various languages, sorted by their names
  35  * (except that the "default" is left at the end).
  36  *
  37  * When writing or updating patterns, assume that the contents these
  38  * patterns are applied to are syntactically correct.  The patterns
  39  * can be simple without implementing all syntactical corner cases, as
  40  * long as they are sufficiently permissive.
  41  */
  42 static struct userdiff_driver builtin_drivers[] = {
  43 IPATTERN("ada",
  44          "!^(.*[ \t])?(is[ \t]+new|renames|is[ \t]+separate)([ \t].*)?$\n"
  45          "!^[ \t]*with[ \t].*$\n"
  46          "^[ \t]*((procedure|function)[ \t]+.*)$\n"
  47          "^[ \t]*((package|protected|task)[ \t]+.*)$",
  48          /* -- */
  49          "[a-zA-Z][a-zA-Z0-9_]*"
  50          "|[-+]?[0-9][0-9#_.aAbBcCdDeEfF]*([eE][+-]?[0-9_]+)?"
  51          "|=>|\\.\\.|\\*\\*|:=|/=|>=|<=|<<|>>|<>"),
  52 PATTERNS("bash",
  53          /* Optional leading indentation */
  54          "^[ \t]*"
  55          /* Start of captured text */
  56          "("
  57          "("
  58              /* POSIX identifier with mandatory parentheses */
  59              "[a-zA-Z_][a-zA-Z0-9_]*[ \t]*\\([ \t]*\\))"
  60          "|"
  61              /* Bashism identifier with optional parentheses */
  62              "(function[ \t]+[a-zA-Z_][a-zA-Z0-9_]*(([ \t]*\\([ \t]*\\))|([ \t]+))"
  63          ")"
  64          /* Optional whitespace */
  65          "[ \t]*"
  66          /* Compound command starting with `{`, `(`, `((` or `[[` */
  67          "(\\{|\\(\\(?|\\[\\[)"
  68          /* End of captured text */
  69          ")",
  70          /* -- */
  71          /* Characters not in the default $IFS value */
  72          "[^ \t]+"),
  73 PATTERNS("bibtex",
  74          "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
  75          /* -- */
  76          "[={}\"]|[^={}\" \t]+"),
  77 PATTERNS("cpp",
  78          /* Jump targets or access declarations */
  79          "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])\n"
  80          /* functions/methods, variables, and compounds at top level */
  81          "^((::[[:space:]]*)?[A-Za-z_].*)$",
  82          /* -- */
  83          /* identifiers and keywords */
  84          "[a-zA-Z_][a-zA-Z0-9_]*"
  85          /* decimal and octal integers as well as floatingpoint numbers */
  86          "|[0-9][0-9.]*([Ee][-+]?[0-9]+)?[fFlLuU]*"
  87          /* hexadecimal and binary integers */
  88          "|0[xXbB][0-9a-fA-F]+[lLuU]*"
  89          /* floatingpoint numbers that begin with a decimal point */
  90          "|\\.[0-9][0-9]*([Ee][-+]?[0-9]+)?[fFlL]?"
  91          "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*|<=>"),
  92 PATTERNS("csharp",
  93          /*
  94           * Jump over reserved keywords which are illegal method names, but which
  95           * can be followed by parentheses without special characters in between,
  96           * making them look like methods.
  97           */
  98          "!(^|[ \t]+)" /* Start of line or whitespace. */
  99                 "(do|while|for|foreach|if|else|new|default|return|switch|case|throw"
 100                 "|catch|using|lock|fixed)"
 101                 "([ \t(]+|$)\n" /* Whitespace, "(", or end of line. */
 102          /*
 103           * Methods/constructors:
 104           * The strategy is to identify a minimum of two groups (any combination
 105           * of keywords/type/name) before the opening parenthesis, and without
 106           * final unexpected characters, normally only used in ordinary statements.
 107           */
 108          "^[ \t]*" /* Remove leading whitespace. */
 109                 "(" /* Start chunk header capture. */
 110                 "(" /* First group. */
 111                         "[][[:alnum:]@_.]" /* Name. */
 112                         "(<[][[:alnum:]@_, \t<>]+>)?" /* Optional generic parameters. */
 113                 ")+"
 114                 "([ \t]+" /* Subsequent groups, prepended with space. */
 115                         "([][[:alnum:]@_.](<[][[:alnum:]@_, \t<>]+>)?)+"
 116                 ")+"
 117                 "[ \t]*" /* Optional space before parameters start. */
 118                 "\\(" /* Start of method parameters. */
 119                 "[^;]*" /* Allow complex parameters, but exclude statements (;). */
 120                 ")$\n" /* Close chunk header capture. */
 121          /*
 122           * Properties:
 123           * As with methods, expect a minimum of two groups. But, more trivial than
 124           * methods, the vast majority of properties long enough to be worth
 125           * showing a chunk header for don't include "=:;,()" on the line they are
 126           * defined, since they don't have a parameter list.
 127           */
 128          "^[ \t]*("
 129                 "([][[:alnum:]@_.](<[][[:alnum:]@_, \t<>]+>)?)+"
 130                 "([ \t]+"
 131                         "([][[:alnum:]@_.](<[][[:alnum:]@_, \t<>]+>)?)+"
 132                 ")+" /* Up to here, same as methods regex. */
 133                 "[^;=:,()]*" /* Compared to methods, no parameter list allowed. */
 134                 ")$\n"
 135          /* Type definitions */
 136          "^[ \t]*(((static|public|internal|private|protected|new|unsafe|sealed|abstract|partial)[ \t]+)*(class|enum|interface|struct|record)[ \t]+.*)$\n"
 137          /* Namespace */
 138          "^[ \t]*(namespace[ \t]+.*)$",
 139          /* -- */
 140          "[a-zA-Z_][a-zA-Z0-9_]*"
 141          "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
 142          "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
 143 IPATTERN("css",
 144          "![:;][[:space:]]*$\n"
 145          "^[:[@.#]?[_a-z0-9].*$",
 146          /* -- */
 147          /*
 148           * This regex comes from W3C CSS specs. Should theoretically also
 149           * allow ISO 10646 characters U+00A0 and higher,
 150           * but they are not handled in this regex.
 151           */
 152          "-?[_a-zA-Z][-_a-zA-Z0-9]*" /* identifiers */
 153          "|-?[0-9]+|\\#[0-9a-fA-F]+" /* numbers */
 154 ),
 155 PATTERNS("dts",
 156          "!;\n"
 157          "!=\n"
 158          /* lines beginning with a word optionally preceded by '&' or the root */
 159          "^[ \t]*((/[ \t]*\\{|&?[a-zA-Z_]).*)",
 160          /* -- */
 161          /* Property names and math operators */
 162          "[a-zA-Z0-9,._+?#-]+"
 163          "|[-+*/%&^|!~]|>>|<<|&&|\\|\\|"),
 164 PATTERNS("elixir",
 165          "^[ \t]*((def(macro|module|impl|protocol|p)?|test)[ \t].*)$",
 166          /* -- */
 167          /* Atoms, names, and module attributes */
 168          "[@:]?[a-zA-Z0-9@_?!]+"
 169          /* Numbers with specific base */
 170          "|[-+]?0[xob][0-9a-fA-F]+"
 171          /* Numbers */
 172          "|[-+]?[0-9][0-9_.]*([eE][-+]?[0-9_]+)?"
 173          /* Operators and atoms that represent them */
 174          "|:?(\\+\\+|--|\\.\\.|~~~|<>|\\^\\^\\^|<?\\|>|<<<?|>?>>|<<?~|~>?>|<~>|<=|>=|===?|!==?|=~|&&&?|\\|\\|\\|?|=>|<-|\\\\\\\\|->)"
 175          /* Not real operators, but should be grouped */
 176          "|:?%[A-Za-z0-9_.]\\{\\}?"),
 177 IPATTERN("fortran",
 178          /* Don't match comment lines */
 179          "!^([C*]|[ \t]*!)\n"
 180          /* Don't match 'module procedure' lines */
 181          "!^[ \t]*MODULE[ \t]+PROCEDURE[ \t]\n"
 182          /* Program, module, block data */
 183          "^[ \t]*((END[ \t]+)?(PROGRAM|MODULE|BLOCK[ \t]+DATA"
 184                 /* Subroutines and functions */
 185                 "|([^!'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
 186          /* -- */
 187          "[a-zA-Z][a-zA-Z0-9_]*"
 188          "|\\.([Ee][Qq]|[Nn][Ee]|[Gg][TtEe]|[Ll][TtEe]|[Tt][Rr][Uu][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Aa][Nn][Dd]|[Oo][Rr]|[Nn]?[Ee][Qq][Vv]|[Nn][Oo][Tt])\\."
 189          /* numbers and format statements like 2E14.4, or ES12.6, 9X.
 190           * Don't worry about format statements without leading digits since
 191           * they would have been matched above as a variable anyway. */
 192          "|[-+]?[0-9.]+([AaIiDdEeFfLlTtXx][Ss]?[-+]?[0-9.]*)?(_[a-zA-Z0-9][a-zA-Z0-9_]*)?"
 193          "|//|\\*\\*|::|[/<>=]="),
 194 IPATTERN("fountain",
 195          "^((\\.[^.]|(int|ext|est|int\\.?/ext|i/e)[. ]).*)$",
 196          /* -- */
 197          "[^ \t-]+"),
 198 PATTERNS("golang",
 199          /* Functions */
 200          "^[ \t]*(func[ \t]*.*(\\{[ \t]*)?)\n"
 201          /* Structs and interfaces */
 202          "^[ \t]*(type[ \t].*(struct|interface)[ \t]*(\\{[ \t]*)?)",
 203          /* -- */
 204          "[a-zA-Z_][a-zA-Z0-9_]*"
 205          "|[-+0-9.eE]+i?|0[xX]?[0-9a-fA-F]+i?"
 206          "|[-+*/<>%&^|=!:]=|--|\\+\\+|<<=?|>>=?|&\\^=?|&&|\\|\\||<-|\\.{3}"),
 207 PATTERNS("html",
 208          "^[ \t]*(<[Hh][1-6]([ \t].*)?>.*)$",
 209          /* -- */
 210          "[^<>= \t]+"),
 211 PATTERNS("java",
 212          "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
 213          /* Class, enum, interface, and record declarations */
 214          "^[ \t]*(([a-z-]+[ \t]+)*(class|enum|interface|record)[ \t]+.*)$\n"
 215          /* Method definitions; note that constructor signatures are not */
 216          /* matched because they are indistinguishable from method calls. */
 217          "^[ \t]*(([A-Za-z_<>&][][?&<>.,A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
 218          /* -- */
 219          "[a-zA-Z_][a-zA-Z0-9_]*"
 220          "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
 221          "|[-+*/<>%&^|=!]="
 222          "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"),
 223 PATTERNS("kotlin",
 224          "^[ \t]*(([a-z]+[ \t]+)*(fun|class|interface)[ \t]+.*)$",
 225          /* -- */
 226          "[a-zA-Z_][a-zA-Z0-9_]*"
 227          /* hexadecimal and binary numbers */
 228          "|0[xXbB][0-9a-fA-F_]+[lLuU]*"
 229          /* integers and floats */
 230          "|[0-9][0-9_]*([.][0-9_]*)?([Ee][-+]?[0-9]+)?[fFlLuU]*"
 231          /* floating point numbers beginning with decimal point */
 232          "|[.][0-9][0-9_]*([Ee][-+]?[0-9]+)?[fFlLuU]?"
 233          /* unary and binary operators */
 234          "|[-+*/<>%&^|=!]==?|--|\\+\\+|<<=|>>=|&&|\\|\\||->|\\.\\*|!!|[?:.][.:]"),
 235 PATTERNS("markdown",
 236          "^ {0,3}#{1,6}[ \t].*",
 237          /* -- */
 238          "[^<>= \t]+"),
 239 PATTERNS("matlab",
 240          /*
 241           * Octave pattern is mostly the same as matlab, except that '%%%' and
 242           * '##' can also be used to begin code sections, in addition to '%%'
 243           * that is understood by both.
 244           */
 245          "^[[:space:]]*((classdef|function)[[:space:]].*)$|^(%%%?|##)[[:space:]].*$",
 246          /* -- */
 247          "[a-zA-Z_][a-zA-Z0-9_]*|[-+0-9.e]+|[=~<>]=|\\.[*/\\^']|\\|\\||&&"),
 248 PATTERNS("objc",
 249          /* Negate C statements that can look like functions */
 250          "!^[ \t]*(do|for|if|else|return|switch|while)\n"
 251          /* Objective-C methods */
 252          "^[ \t]*([-+][ \t]*\\([ \t]*[A-Za-z_][A-Za-z_0-9* \t]*\\)[ \t]*[A-Za-z_].*)$\n"
 253          /* C functions */
 254          "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$\n"
 255          /* Objective-C class/protocol definitions */
 256          "^(@(implementation|interface|protocol)[ \t].*)$",
 257          /* -- */
 258          "[a-zA-Z_][a-zA-Z0-9_]*"
 259          "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
 260          "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
 261 PATTERNS("pascal",
 262          "^(((class[ \t]+)?(procedure|function)|constructor|destructor|interface"
 263          "|implementation|initialization|finalization)[ \t]*.*)$\n"
 264          "^(.*=[ \t]*(class|record).*)$",
 265          /* -- */
 266          "[a-zA-Z_][a-zA-Z0-9_]*"
 267          "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
 268          "|<>|<=|>=|:=|\\.\\."),
 269 PATTERNS("perl",
 270          "^package .*\n"
 271          "^sub [[:alnum:]_':]+[ \t]*"
 272                 "(\\([^)]*\\)[ \t]*)?" /* prototype */
 273                 /*
 274                  * Attributes.  A regex can't count nested parentheses,
 275                  * so just slurp up whatever we see, taking care not
 276                  * to accept lines like "sub foo; # defined elsewhere".
 277                  *
 278                  * An attribute could contain a semicolon, but at that
 279                  * point it seems reasonable enough to give up.
 280                  */
 281                 "(:[^;#]*)?"
 282                 "(\\{[ \t]*)?" /* brace can come here or on the next line */
 283                 "(#.*)?$\n" /* comment */
 284          "^(BEGIN|END|INIT|CHECK|UNITCHECK|AUTOLOAD|DESTROY)[ \t]*"
 285                 "(\\{[ \t]*)?" /* brace can come here or on the next line */
 286                 "(#.*)?$\n"
 287          "^=head[0-9] .*",      /* POD */
 288          /* -- */
 289          "[[:alpha:]_'][[:alnum:]_']*"
 290          "|0[xb]?[0-9a-fA-F_]*"
 291          /* taking care not to interpret 3..5 as (3.)(.5) */
 292          "|[0-9a-fA-F_]+(\\.[0-9a-fA-F_]+)?([eE][-+]?[0-9_]+)?"
 293          "|=>|-[rwxoRWXOezsfdlpSugkbctTBMAC>]|~~|::"
 294          "|&&=|\\|\\|=|//=|\\*\\*="
 295          "|&&|\\|\\||//|\\+\\+|--|\\*\\*|\\.\\.\\.?"
 296          "|[-+*/%.^&<>=!|]="
 297          "|=~|!~"
 298          "|<<|<>|<=>|>>"),
 299 PATTERNS("php",
 300          "^[\t ]*(((public|protected|private|static|abstract|final)[\t ]+)*function.*)$\n"
 301          "^[\t ]*((((final|abstract)[\t ]+)?class|enum|interface|trait).*)$",
 302          /* -- */
 303          "[a-zA-Z_][a-zA-Z0-9_]*"
 304          "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
 305          "|[-+*/<>%&^|=!.]=|--|\\+\\+|<<=?|>>=?|===|&&|\\|\\||::|->"),
 306 PATTERNS("python",
 307          "^[ \t]*((class|(async[ \t]+)?def)[ \t].*)$",
 308          /* -- */
 309          "[a-zA-Z_][a-zA-Z0-9_]*"
 310          "|[-+0-9.e]+[jJlL]?|0[xX]?[0-9a-fA-F]+[lL]?"
 311          "|[-+*/<>%&^|=!]=|//=?|<<=?|>>=?|\\*\\*=?"),
 312          /* -- */
 313 PATTERNS("ruby",
 314          "^[ \t]*((class|module|def)[ \t].*)$",
 315          /* -- */
 316          "(@|@@|\\$)?[a-zA-Z_][a-zA-Z0-9_]*"
 317          "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+|\\?(\\\\C-)?(\\\\M-)?."
 318          "|//=?|[-+*/<>%&^|=!]=|<<=?|>>=?|===|\\.{1,3}|::|[!=]~"),
 319 PATTERNS("rust",
 320          "^[\t ]*((pub(\\([^\\)]+\\))?[\t ]+)?((async|const|unsafe|extern([\t ]+\"[^\"]+\"))[\t ]+)?(struct|enum|union|mod|trait|fn|impl|macro_rules!)[< \t]+[^;]*)$",
 321          /* -- */
 322          "[a-zA-Z_][a-zA-Z0-9_]*"
 323          "|[0-9][0-9_a-fA-Fiosuxz]*(\\.([0-9]*[eE][+-]?)?[0-9_fF]*)?"
 324          "|[-+*\\/<>%&^|=!:]=|<<=?|>>=?|&&|\\|\\||->|=>|\\.{2}=|\\.{3}|::"),
 325 PATTERNS("scheme",
 326          "^[\t ]*(\\(((define|def(struct|syntax|class|method|rules|record|proto|alias)?)[-*/ \t]|(library|module|struct|class)[*+ \t]).*)$",
 327          /*
 328           * R7RS valid identifiers include any sequence enclosed
 329           * within vertical lines having no backslashes
 330           */
 331          "\\|([^\\\\]*)\\|"
 332          /* All other words should be delimited by spaces or parentheses */
 333          "|([^][)(}{[ \t])+"),
 334 PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
 335          "\\\\[a-zA-Z@]+|\\\\.|([a-zA-Z0-9]|[^\x01-\x7f])+"),
 336 { "default", NULL, NULL, -1, { NULL, 0 } },
 337 };
 338 #undef PATTERNS
 339 #undef IPATTERN
 340
 341 static struct userdiff_driver driver_true = {
 342         .name = "diff=true",
 343         .binary = 0,
 344 };
 345
 346 static struct userdiff_driver driver_false = {
 347         .name = "!diff",
 348         .binary = 1,
 349 };
 350
 351 struct find_by_namelen_data {
 352         const char *name;
 353         size_t len;
 354         struct userdiff_driver *driver;
 355 };
 356
 357 static int userdiff_find_by_namelen_cb(struct userdiff_driver *driver,
 358                                        enum userdiff_driver_type type UNUSED,
 359                                        void *priv)
 360 {
 361         struct find_by_namelen_data *cb_data = priv;
 362
 363         if (!xstrncmpz(driver->name, cb_data->name, cb_data->len)) {
 364                 cb_data->driver = driver;
 365                 return 1; /* tell the caller to stop iterating */
 366         }
 367         return 0;
 368 }
 369
 370 static int regexec_supports_multi_byte_chars(void)
 371 {
 372         static const char not_space[] = "[^[:space:]]";
 373         static const char utf8_multi_byte_char[] = "\xc2\xa3";
 374         regex_t re;
 375         regmatch_t match;
 376         static int result = -1;
 377
 378         if (result != -1)
 379                 return result;
 380         if (regcomp(&re, not_space, REG_EXTENDED))
 381                 BUG("invalid regular expression: %s", not_space);
 382         result = !regexec(&re, utf8_multi_byte_char, 1, &match, 0) &&
 383                 match.rm_so == 0 &&
 384                 match.rm_eo == strlen(utf8_multi_byte_char);
 385         regfree(&re);
 386         return result;
 387 }
 388
 389 static struct userdiff_driver *userdiff_find_by_namelen(const char *name, size_t len)
 390 {
 391         struct find_by_namelen_data udcbdata = {
 392                 .name = name,
 393                 .len = len,
 394         };
 395         for_each_userdiff_driver(userdiff_find_by_namelen_cb, &udcbdata);
 396         return udcbdata.driver;
 397 }
 398
 399 static int parse_funcname(struct userdiff_funcname *f, const char *k,
 400                 const char *v, int cflags)
 401 {
 402         if (git_config_string(&f->pattern, k, v) < 0)
 403                 return -1;
 404         f->cflags = cflags;
 405         return 0;
 406 }
 407
 408 static int parse_tristate(int *b, const char *k, const char *v)
 409 {
 410         if (v && !strcasecmp(v, "auto"))
 411                 *b = -1;
 412         else
 413                 *b = git_config_bool(k, v);
 414         return 0;
 415 }
 416
 417 static int parse_bool(int *b, const char *k, const char *v)
 418 {
 419         *b = git_config_bool(k, v);
 420         return 0;
 421 }
 422
 423 int userdiff_config(const char *k, const char *v)
 424 {
 425         struct userdiff_driver *drv;
 426         const char *name, *type;
 427         size_t namelen;
 428
 429         if (parse_config_key(k, "diff", &name, &namelen, &type) || !name)
 430                 return 0;
 431
 432         drv = userdiff_find_by_namelen(name, namelen);
 433         if (!drv) {
 434                 ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
 435                 drv = &drivers[ndrivers++];
 436                 memset(drv, 0, sizeof(*drv));
 437                 drv->name = xmemdupz(name, namelen);
 438                 drv->binary = -1;
 439         }
 440
 441         if (!strcmp(type, "funcname"))
 442                 return parse_funcname(&drv->funcname, k, v, 0);
 443         if (!strcmp(type, "xfuncname"))
 444                 return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
 445         if (!strcmp(type, "binary"))
 446                 return parse_tristate(&drv->binary, k, v);
 447         if (!strcmp(type, "command"))
 448                 return git_config_string(&drv->external, k, v);
 449         if (!strcmp(type, "textconv"))
 450                 return git_config_string(&drv->textconv, k, v);
 451         if (!strcmp(type, "cachetextconv"))
 452                 return parse_bool(&drv->textconv_want_cache, k, v);
 453         if (!strcmp(type, "wordregex"))
 454                 return git_config_string(&drv->word_regex, k, v);
 455         if (!strcmp(type, "algorithm"))
 456                 return git_config_string(&drv->algorithm, k, v);
 457
 458         return 0;
 459 }
 460
 461 struct userdiff_driver *userdiff_find_by_name(const char *name)
 462 {
 463         int len = strlen(name);
 464         struct userdiff_driver *driver = userdiff_find_by_namelen(name, len);
 465         if (driver && driver->word_regex_multi_byte) {
 466                 if (regexec_supports_multi_byte_chars())
 467                         driver->word_regex = driver->word_regex_multi_byte;
 468                 driver->word_regex_multi_byte = NULL;
 469         }
 470         return driver;
 471 }
 472
 473 struct userdiff_driver *userdiff_find_by_path(struct index_state *istate,
 474                                               const char *path)
 475 {
 476         static struct attr_check *check;
 477
 478         if (!check)
 479                 check = attr_check_initl("diff", NULL);
 480         if (!path)
 481                 return NULL;
 482         git_check_attr(istate, path, check);
 483
 484         if (ATTR_TRUE(check->items[0].value))
 485                 return &driver_true;
 486         if (ATTR_FALSE(check->items[0].value))
 487                 return &driver_false;
 488         if (ATTR_UNSET(check->items[0].value))
 489                 return NULL;
 490         return userdiff_find_by_name(check->items[0].value);
 491 }
 492
 493 struct userdiff_driver *userdiff_get_textconv(struct repository *r,
 494                                               struct userdiff_driver *driver)
 495 {
 496         if (!driver->textconv)
 497                 return NULL;
 498
 499         if (driver->textconv_want_cache && !driver->textconv_cache &&
 500             have_git_dir()) {
 501                 struct notes_cache *c = xmalloc(sizeof(*c));
 502                 struct strbuf name = STRBUF_INIT;
 503
 504                 strbuf_addf(&name, "textconv/%s", driver->name);
 505                 notes_cache_init(r, c, name.buf, driver->textconv);
 506                 driver->textconv_cache = c;
 507                 strbuf_release(&name);
 508         }
 509
 510         return driver;
 511 }
 512
 513 static int for_each_userdiff_driver_list(each_userdiff_driver_fn fn,
 514                                          enum userdiff_driver_type type, void *cb_data,
 515                                          struct userdiff_driver *drv,
 516                                          int drv_size)
 517 {
 518         int i;
 519         int ret;
 520         for (i = 0; i < drv_size; i++) {
 521                 struct userdiff_driver *item = drv + i;
 522                 if ((ret = fn(item, type, cb_data)))
 523                         return ret;
 524         }
 525         return 0;
 526 }
 527
 528 int for_each_userdiff_driver(each_userdiff_driver_fn fn, void *cb_data)
 529 {
 530         int ret;
 531
 532         ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_CUSTOM,
 533                                             cb_data, drivers, ndrivers);
 534         if (ret)
 535                 return ret;
 536
 537         ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_BUILTIN,
 538                                             cb_data, builtin_drivers,
 539                                             ARRAY_SIZE(builtin_drivers));
 540         if (ret)
 541                 return ret;
 542
 543         return 0;
 544 }