git

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#include "git-compat-util.h"
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#include "config.h"
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#include "userdiff.h"
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#include "attr.h"
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#include "strbuf.h"
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#include "environment.h"
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static struct userdiff_driver *drivers;
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static int ndrivers;
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static int drivers_alloc;
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#define PATTERNS(lang, rx, wrx) { \
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	.name = lang, \
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	.binary = -1, \
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	.funcname = { \
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		.pattern = rx, \
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		.cflags = REG_EXTENDED, \
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	}, \
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	.word_regex = wrx "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+", \
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	.word_regex_multi_byte = wrx "|[^[:space:]]", \
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}
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#define IPATTERN(lang, rx, wrx) { \
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	.name = lang, \
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	.binary = -1, \
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	.funcname = { \
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		.pattern = rx, \
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		.cflags = REG_EXTENDED | REG_ICASE, \
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	}, \
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	.word_regex = wrx "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+", \
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	.word_regex_multi_byte = wrx "|[^[:space:]]", \
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}
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/*
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 * Built-in drivers for various languages, sorted by their names
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 * (except that the "default" is left at the end).
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 *
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 * When writing or updating patterns, assume that the contents these
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 * patterns are applied to are syntactically correct.  The patterns
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 * can be simple without implementing all syntactical corner cases, as
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 * long as they are sufficiently permissive.
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 */
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static struct userdiff_driver builtin_drivers[] = {
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IPATTERN("ada",
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	 "!^(.*[ \t])?(is[ \t]+new|renames|is[ \t]+separate)([ \t].*)?$\n"
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	 "!^[ \t]*with[ \t].*$\n"
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	 "^[ \t]*((procedure|function)[ \t]+.*)$\n"
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	 "^[ \t]*((package|protected|task)[ \t]+.*)$",
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	 /* -- */
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	 "[a-zA-Z][a-zA-Z0-9_]*"
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	 "|[-+]?[0-9][0-9#_.aAbBcCdDeEfF]*([eE][+-]?[0-9_]+)?"
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	 "|=>|\\.\\.|\\*\\*|:=|/=|>=|<=|<<|>>|<>"),
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PATTERNS("bash",
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	 /* Optional leading indentation */
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	 "^[ \t]*"
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	 /* Start of captured text */
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	 "("
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	 "("
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	     /* POSIX identifier with mandatory parentheses */
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	     "[a-zA-Z_][a-zA-Z0-9_]*[ \t]*\\([ \t]*\\))"
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	 "|"
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	     /* Bashism identifier with optional parentheses */
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	     "(function[ \t]+[a-zA-Z_][a-zA-Z0-9_]*(([ \t]*\\([ \t]*\\))|([ \t]+))"
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	 ")"
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	 /* Optional whitespace */
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	 "[ \t]*"
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	 /* Compound command starting with `{`, `(`, `((` or `[[` */
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	 "(\\{|\\(\\(?|\\[\\[)"
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	 /* End of captured text */
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	 ")",
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	 /* -- */
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	 /* Characters not in the default $IFS value */
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	 "[^ \t]+"),
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PATTERNS("bibtex",
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	 "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
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	 /* -- */
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	 "[={}\"]|[^={}\" \t]+"),
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PATTERNS("cpp",
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	 /* Jump targets or access declarations */
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	 "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])\n"
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	 /* functions/methods, variables, and compounds at top level */
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	 "^((::[[:space:]]*)?[A-Za-z_].*)$",
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	 /* -- */
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	 /* identifiers and keywords */
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	 "[a-zA-Z_][a-zA-Z0-9_]*"
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	 /* decimal and octal integers as well as floatingpoint numbers */
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	 "|[0-9][0-9.]*([Ee][-+]?[0-9]+)?[fFlLuU]*"
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	 /* hexadecimal and binary integers */
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	 "|0[xXbB][0-9a-fA-F]+[lLuU]*"
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	 /* floatingpoint numbers that begin with a decimal point */
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	 "|\\.[0-9][0-9]*([Ee][-+]?[0-9]+)?[fFlL]?"
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	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*|<=>"),
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PATTERNS("csharp",
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	 /*
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	  * Jump over reserved keywords which are illegal method names, but which
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	  * can be followed by parentheses without special characters in between,
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	  * making them look like methods.
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	  */
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	 "!(^|[ \t]+)" /* Start of line or whitespace. */
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		"(do|while|for|foreach|if|else|new|default|return|switch|case|throw"
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		"|catch|using|lock|fixed)"
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		"([ \t(]+|$)\n" /* Whitespace, "(", or end of line. */
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	 /*
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	  * Methods/constructors:
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	  * The strategy is to identify a minimum of two groups (any combination
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	  * of keywords/type/name) before the opening parenthesis, and without
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	  * final unexpected characters, normally only used in ordinary statements.
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	  */
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	 "^[ \t]*" /* Remove leading whitespace. */
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		"(" /* Start chunk header capture. */
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		"(" /* First group. */
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			"[][[:alnum:]@_.]" /* Name. */
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			"(<[][[:alnum:]@_, \t<>]+>)?" /* Optional generic parameters. */
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		")+"
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		"([ \t]+" /* Subsequent groups, prepended with space. */
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			"([][[:alnum:]@_.](<[][[:alnum:]@_, \t<>]+>)?)+"
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		")+"
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		"[ \t]*" /* Optional space before parameters start. */
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		"\\(" /* Start of method parameters. */
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		"[^;]*" /* Allow complex parameters, but exclude statements (;). */
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		")$\n" /* Close chunk header capture. */
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	 /*
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	  * Properties:
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	  * As with methods, expect a minimum of two groups. But, more trivial than
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	  * methods, the vast majority of properties long enough to be worth
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	  * showing a chunk header for don't include "=:;,()" on the line they are
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	  * defined, since they don't have a parameter list.
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	  */
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	 "^[ \t]*("
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		"([][[:alnum:]@_.](<[][[:alnum:]@_, \t<>]+>)?)+"
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		"([ \t]+"
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			"([][[:alnum:]@_.](<[][[:alnum:]@_, \t<>]+>)?)+"
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		")+" /* Up to here, same as methods regex. */
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		"[^;=:,()]*" /* Compared to methods, no parameter list allowed. */
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		")$\n"
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	 /* Type definitions */
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	 "^[ \t]*(((static|public|internal|private|protected|new|unsafe|sealed|abstract|partial)[ \t]+)*(class|enum|interface|struct|record)[ \t]+.*)$\n"
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	 /* Namespace */
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	 "^[ \t]*(namespace[ \t]+.*)$",
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	 /* -- */
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	 "[a-zA-Z_][a-zA-Z0-9_]*"
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	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
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	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
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IPATTERN("css",
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	 "![:;][[:space:]]*$\n"
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	 "^[:[@.#]?[_a-z0-9].*$",
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	 /* -- */
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	 /*
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	  * This regex comes from W3C CSS specs. Should theoretically also
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	  * allow ISO 10646 characters U+00A0 and higher,
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	  * but they are not handled in this regex.
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	  */
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	 "-?[_a-zA-Z][-_a-zA-Z0-9]*" /* identifiers */
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	 "|-?[0-9]+|\\#[0-9a-fA-F]+" /* numbers */
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),
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PATTERNS("dts",
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	 "!;\n"
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	 "!=\n"
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	 /* lines beginning with a word optionally preceded by '&' or the root */
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	 "^[ \t]*((/[ \t]*\\{|&?[a-zA-Z_]).*)",
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	 /* -- */
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	 /* Property names and math operators */
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	 "[a-zA-Z0-9,._+?#-]+"
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	 "|[-+*/%&^|!~]|>>|<<|&&|\\|\\|"),
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PATTERNS("elixir",
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	 "^[ \t]*((def(macro|module|impl|protocol|p)?|test)[ \t].*)$",
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	 /* -- */
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	 /* Atoms, names, and module attributes */
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	 "[@:]?[a-zA-Z0-9@_?!]+"
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	 /* Numbers with specific base */
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	 "|[-+]?0[xob][0-9a-fA-F]+"
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	 /* Numbers */
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	 "|[-+]?[0-9][0-9_.]*([eE][-+]?[0-9_]+)?"
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	 /* Operators and atoms that represent them */
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	 "|:?(\\+\\+|--|\\.\\.|~~~|<>|\\^\\^\\^|<?\\|>|<<<?|>?>>|<<?~|~>?>|<~>|<=|>=|===?|!==?|=~|&&&?|\\|\\|\\|?|=>|<-|\\\\\\\\|->)"
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	 /* Not real operators, but should be grouped */
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	 "|:?%[A-Za-z0-9_.]\\{\\}?"),
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IPATTERN("fortran",
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	 /* Don't match comment lines */
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	 "!^([C*]|[ \t]*!)\n"
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	 /* Don't match 'module procedure' lines */
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	 "!^[ \t]*MODULE[ \t]+PROCEDURE[ \t]\n"
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	 /* Program, module, block data */
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	 "^[ \t]*((END[ \t]+)?(PROGRAM|MODULE|BLOCK[ \t]+DATA"
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		/* Subroutines and functions */
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		"|([^!'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
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	 /* -- */
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	 "[a-zA-Z][a-zA-Z0-9_]*"
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	 "|\\.([Ee][Qq]|[Nn][Ee]|[Gg][TtEe]|[Ll][TtEe]|[Tt][Rr][Uu][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Aa][Nn][Dd]|[Oo][Rr]|[Nn]?[Ee][Qq][Vv]|[Nn][Oo][Tt])\\."
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	 /* numbers and format statements like 2E14.4, or ES12.6, 9X.
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	  * Don't worry about format statements without leading digits since
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	  * they would have been matched above as a variable anyway. */
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	 "|[-+]?[0-9.]+([AaIiDdEeFfLlTtXx][Ss]?[-+]?[0-9.]*)?(_[a-zA-Z0-9][a-zA-Z0-9_]*)?"
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	 "|//|\\*\\*|::|[/<>=]="),
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IPATTERN("fountain",
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	 "^((\\.[^.]|(int|ext|est|int\\.?/ext|i/e)[. ]).*)$",
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	 /* -- */
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	 "[^ \t-]+"),
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PATTERNS("golang",
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	 /* Functions */
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	 "^[ \t]*(func[ \t]*.*(\\{[ \t]*)?)\n"
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	 /* Structs and interfaces */
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	 "^[ \t]*(type[ \t].*(struct|interface)[ \t]*(\\{[ \t]*)?)",
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	 /* -- */
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	 "[a-zA-Z_][a-zA-Z0-9_]*"
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	 "|[-+0-9.eE]+i?|0[xX]?[0-9a-fA-F]+i?"
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	 "|[-+*/<>%&^|=!:]=|--|\\+\\+|<<=?|>>=?|&\\^=?|&&|\\|\\||<-|\\.{3}"),
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PATTERNS("html",
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	 "^[ \t]*(<[Hh][1-6]([ \t].*)?>.*)$",
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	 /* -- */
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	 "[^<>= \t]+"),
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PATTERNS("java",
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	 "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
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	 /* Class, enum, interface, and record declarations */
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	 "^[ \t]*(([a-z-]+[ \t]+)*(class|enum|interface|record)[ \t]+.*)$\n"
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	 /* Method definitions; note that constructor signatures are not */
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	 /* matched because they are indistinguishable from method calls. */
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	 "^[ \t]*(([A-Za-z_<>&][][?&<>.,A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
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	 /* -- */
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	 "[a-zA-Z_][a-zA-Z0-9_]*"
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	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
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	 "|[-+*/<>%&^|=!]="
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	 "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"),
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PATTERNS("kotlin",
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	 "^[ \t]*(([a-z]+[ \t]+)*(fun|class|interface)[ \t]+.*)$",
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	 /* -- */
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	 "[a-zA-Z_][a-zA-Z0-9_]*"
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	 /* hexadecimal and binary numbers */
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	 "|0[xXbB][0-9a-fA-F_]+[lLuU]*"
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	 /* integers and floats */
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	 "|[0-9][0-9_]*([.][0-9_]*)?([Ee][-+]?[0-9]+)?[fFlLuU]*"
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	 /* floating point numbers beginning with decimal point */
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	 "|[.][0-9][0-9_]*([Ee][-+]?[0-9]+)?[fFlLuU]?"
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	 /* unary and binary operators */
234
	 "|[-+*/<>%&^|=!]==?|--|\\+\\+|<<=|>>=|&&|\\|\\||->|\\.\\*|!!|[?:.][.:]"),
235
PATTERNS("markdown",
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	 "^ {0,3}#{1,6}[ \t].*",
237
	 /* -- */
238
	 "[^<>= \t]+"),
239
PATTERNS("matlab",
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	 /*
241
	  * Octave pattern is mostly the same as matlab, except that '%%%' and
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	  * '##' can also be used to begin code sections, in addition to '%%'
243
	  * that is understood by both.
244
	  */
245
	 "^[[:space:]]*((classdef|function)[[:space:]].*)$|^(%%%?|##)[[:space:]].*$",
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	 /* -- */
247
	 "[a-zA-Z_][a-zA-Z0-9_]*|[-+0-9.e]+|[=~<>]=|\\.[*/\\^']|\\|\\||&&"),
248
PATTERNS("objc",
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	 /* Negate C statements that can look like functions */
250
	 "!^[ \t]*(do|for|if|else|return|switch|while)\n"
251
	 /* Objective-C methods */
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	 "^[ \t]*([-+][ \t]*\\([ \t]*[A-Za-z_][A-Za-z_0-9* \t]*\\)[ \t]*[A-Za-z_].*)$\n"
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	 /* C functions */
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	 "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$\n"
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	 /* Objective-C class/protocol definitions */
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	 "^(@(implementation|interface|protocol)[ \t].*)$",
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	 /* -- */
258
	 "[a-zA-Z_][a-zA-Z0-9_]*"
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	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
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	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
261
PATTERNS("pascal",
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	 "^(((class[ \t]+)?(procedure|function)|constructor|destructor|interface"
263
	 "|implementation|initialization|finalization)[ \t]*.*)$\n"
264
	 "^(.*=[ \t]*(class|record).*)$",
265
	 /* -- */
266
	 "[a-zA-Z_][a-zA-Z0-9_]*"
267
	 "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
268
	 "|<>|<=|>=|:=|\\.\\."),
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PATTERNS("perl",
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	 "^package .*\n"
271
	 "^sub [[:alnum:]_':]+[ \t]*"
272
		"(\\([^)]*\\)[ \t]*)?" /* prototype */
273
		/*
274
		 * Attributes.  A regex can't count nested parentheses,
275
		 * so just slurp up whatever we see, taking care not
276
		 * to accept lines like "sub foo; # defined elsewhere".
277
		 *
278
		 * An attribute could contain a semicolon, but at that
279
		 * point it seems reasonable enough to give up.
280
		 */
281
		"(:[^;#]*)?"
282
		"(\\{[ \t]*)?" /* brace can come here or on the next line */
283
		"(#.*)?$\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
{ .name = "default", .binary = -1 },
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
	f->pattern = NULL;
403
	FREE_AND_NULL(f->pattern_owned);
404
	if (git_config_string(&f->pattern_owned, k, v) < 0)
405
		return -1;
406
	f->pattern = f->pattern_owned;
407
	f->cflags = cflags;
408
	return 0;
409
}
410

411
static int parse_tristate(int *b, const char *k, const char *v)
412
{
413
	if (v && !strcasecmp(v, "auto"))
414
		*b = -1;
415
	else
416
		*b = git_config_bool(k, v);
417
	return 0;
418
}
419

420
static int parse_bool(int *b, const char *k, const char *v)
421
{
422
	*b = git_config_bool(k, v);
423
	return 0;
424
}
425

426
int userdiff_config(const char *k, const char *v)
427
{
428
	struct userdiff_driver *drv;
429
	const char *name, *type;
430
	size_t namelen;
431

432
	if (parse_config_key(k, "diff", &name, &namelen, &type) || !name)
433
		return 0;
434

435
	drv = userdiff_find_by_namelen(name, namelen);
436
	if (!drv) {
437
		ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
438
		drv = &drivers[ndrivers++];
439
		memset(drv, 0, sizeof(*drv));
440
		drv->name = xmemdupz(name, namelen);
441
		drv->binary = -1;
442
	}
443

444
	if (!strcmp(type, "funcname"))
445
		return parse_funcname(&drv->funcname, k, v, 0);
446
	if (!strcmp(type, "xfuncname"))
447
		return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
448
	if (!strcmp(type, "binary"))
449
		return parse_tristate(&drv->binary, k, v);
450
	if (!strcmp(type, "command")) {
451
		FREE_AND_NULL(drv->external.cmd);
452
		return git_config_string(&drv->external.cmd, k, v);
453
	}
454
	if (!strcmp(type, "trustexitcode")) {
455
		drv->external.trust_exit_code = git_config_bool(k, v);
456
		return 0;
457
	}
458
	if (!strcmp(type, "textconv")) {
459
		int ret;
460
		FREE_AND_NULL(drv->textconv_owned);
461
		ret = git_config_string(&drv->textconv_owned, k, v);
462
		drv->textconv = drv->textconv_owned;
463
		return ret;
464
	}
465
	if (!strcmp(type, "cachetextconv"))
466
		return parse_bool(&drv->textconv_want_cache, k, v);
467
	if (!strcmp(type, "wordregex")) {
468
		int ret;
469
		FREE_AND_NULL(drv->word_regex_owned);
470
		ret = git_config_string(&drv->word_regex_owned, k, v);
471
		drv->word_regex = drv->word_regex_owned;
472
		return ret;
473
	}
474
	if (!strcmp(type, "algorithm")) {
475
		int ret;
476
		FREE_AND_NULL(drv->algorithm_owned);
477
		ret = git_config_string(&drv->algorithm_owned, k, v);
478
		drv->algorithm = drv->algorithm_owned;
479
		return ret;
480
	}
481

482
	return 0;
483
}
484

485
struct userdiff_driver *userdiff_find_by_name(const char *name)
486
{
487
	int len = strlen(name);
488
	struct userdiff_driver *driver = userdiff_find_by_namelen(name, len);
489
	if (driver && driver->word_regex_multi_byte) {
490
		if (regexec_supports_multi_byte_chars())
491
			driver->word_regex = driver->word_regex_multi_byte;
492
		driver->word_regex_multi_byte = NULL;
493
	}
494
	return driver;
495
}
496

497
struct userdiff_driver *userdiff_find_by_path(struct index_state *istate,
498
					      const char *path)
499
{
500
	static struct attr_check *check;
501

502
	if (!check)
503
		check = attr_check_initl("diff", NULL);
504
	if (!path)
505
		return NULL;
506
	git_check_attr(istate, path, check);
507

508
	if (ATTR_TRUE(check->items[0].value))
509
		return &driver_true;
510
	if (ATTR_FALSE(check->items[0].value))
511
		return &driver_false;
512
	if (ATTR_UNSET(check->items[0].value))
513
		return NULL;
514
	return userdiff_find_by_name(check->items[0].value);
515
}
516

517
struct userdiff_driver *userdiff_get_textconv(struct repository *r,
518
					      struct userdiff_driver *driver)
519
{
520
	if (!driver->textconv)
521
		return NULL;
522

523
	if (driver->textconv_want_cache && !driver->textconv_cache &&
524
	    have_git_dir()) {
525
		struct notes_cache *c = xmalloc(sizeof(*c));
526
		struct strbuf name = STRBUF_INIT;
527

528
		strbuf_addf(&name, "textconv/%s", driver->name);
529
		notes_cache_init(r, c, name.buf, driver->textconv);
530
		driver->textconv_cache = c;
531
		strbuf_release(&name);
532
	}
533

534
	return driver;
535
}
536

537
static int for_each_userdiff_driver_list(each_userdiff_driver_fn fn,
538
					 enum userdiff_driver_type type, void *cb_data,
539
					 struct userdiff_driver *drv,
540
					 int drv_size)
541
{
542
	int i;
543
	int ret;
544
	for (i = 0; i < drv_size; i++) {
545
		struct userdiff_driver *item = drv + i;
546
		if ((ret = fn(item, type, cb_data)))
547
			return ret;
548
	}
549
	return 0;
550
}
551

552
int for_each_userdiff_driver(each_userdiff_driver_fn fn, void *cb_data)
553
{
554
	int ret;
555

556
	ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_CUSTOM,
557
					    cb_data, drivers, ndrivers);
558
	if (ret)
559
		return ret;
560

561
	ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_BUILTIN,
562
					    cb_data, builtin_drivers,
563
					    ARRAY_SIZE(builtin_drivers));
564
	if (ret)
565
		return ret;
566

567
	return 0;
568
}
569