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userdiff: simplify word-diff safeguard

git's diff-words support has a detail that can be a little dangerous:
any text not matched by a given language's tokenization pattern is
treated as whitespace and changes in such text would go unnoticed.
Therefore each of the built-in regexes allows a special token type
consisting of a single non-whitespace character [^[:space:]].

To make sure UTF-8 sequences remain human readable, the builtin
regexes also have a special token type for runs of bytes with the high
bit set.  In English, non-ASCII characters are usually isolated so
this is analogous to the [^[:space:]] pattern, except it matches a
single _multibyte_ character despite use of the C locale.

Unfortunately it is easy to make typos or forget entirely to include
these catch-all token types when adding support for new languages (see
v1.7.3.5~16, userdiff: fix typo in ruby and python word regexes,
2010-12-18).  Avoid this by including them automatically within the
PATTERNS and IPATTERN macros.

While at it, change the UTF-8 sequence token type to match exactly one
non-ASCII multi-byte character, rather than an arbitrary run of them.

Suggested-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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1 parent 8d96e72 commit 664d44ee7fb18bdfdd66a1be760c7ee1bbe911c6 @jrn jrn committed with gitster Jan 11, 2011
Showing with 16 additions and 24 deletions.
  1. +16 −24 userdiff.c
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@@ -8,9 +8,11 @@ static int ndrivers;
static int drivers_alloc;
#define PATTERNS(name, pattern, word_regex) \
- { name, NULL, -1, { pattern, REG_EXTENDED }, word_regex }
+ { name, NULL, -1, { pattern, REG_EXTENDED }, \
+ word_regex "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+" }
#define IPATTERN(name, pattern, word_regex) \
- { name, NULL, -1, { pattern, REG_EXTENDED | REG_ICASE }, word_regex }
+ { name, NULL, -1, { pattern, REG_EXTENDED | REG_ICASE }, \
+ word_regex "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+" }
static struct userdiff_driver builtin_drivers[] = {
IPATTERN("fortran",
"!^([C*]|[ \t]*!)\n"
@@ -24,19 +26,17 @@ IPATTERN("fortran",
* Don't worry about format statements without leading digits since
* they would have been matched above as a variable anyway. */
"|[-+]?[0-9.]+([AaIiDdEeFfLlTtXx][Ss]?[-+]?[0-9.]*)?(_[a-zA-Z0-9][a-zA-Z0-9_]*)?"
- "|//|\\*\\*|::|[/<>=]="
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|//|\\*\\*|::|[/<>=]="),
PATTERNS("html", "^[ \t]*(<[Hh][1-6][ \t].*>.*)$",
- "[^<>= \t]+|[^[:space:]]|[\x80-\xff]+"),
+ "[^<>= \t]+"),
PATTERNS("java",
"!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
"^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
"|[-+*/<>%&^|=!]="
- "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"),
PATTERNS("objc",
/* Negate C statements that can look like functions */
"!^[ \t]*(do|for|if|else|return|switch|while)\n"
@@ -49,8 +49,7 @@ PATTERNS("objc",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
- "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
PATTERNS("pascal",
"^((procedure|function|constructor|destructor|interface|"
"implementation|initialization|finalization)[ \t]*.*)$"
@@ -59,8 +58,7 @@ PATTERNS("pascal",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
- "|<>|<=|>=|:=|\\.\\."
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|<>|<=|>=|:=|\\.\\."),
PATTERNS("perl",
"^[ \t]*package .*;\n"
"^[ \t]*sub .* \\{\n"
@@ -76,33 +74,29 @@ PATTERNS("perl",
"|&&|\\|\\||//|\\+\\+|--|\\*\\*|\\.\\.\\.?"
"|[-+*/%.^&<>=!|]="
"|=~|!~"
- "|<<|<>|<=>|>>"
- "|[^[:space:]]"),
+ "|<<|<>|<=>|>>"),
PATTERNS("php",
"^[\t ]*(((public|protected|private|static)[\t ]+)*function.*)$\n"
"^[\t ]*(class.*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
- "|[-+*/<>%&^|=!.]=|--|\\+\\+|<<=?|>>=?|===|&&|\\|\\||::|->"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|[-+*/<>%&^|=!.]=|--|\\+\\+|<<=?|>>=?|===|&&|\\|\\||::|->"),
PATTERNS("python", "^[ \t]*((class|def)[ \t].*)$",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[jJlL]?|0[xX]?[0-9a-fA-F]+[lL]?"
- "|[-+*/<>%&^|=!]=|//=?|<<=?|>>=?|\\*\\*=?"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|[-+*/<>%&^|=!]=|//=?|<<=?|>>=?|\\*\\*=?"),
/* -- */
PATTERNS("ruby", "^[ \t]*((class|module|def)[ \t].*)$",
/* -- */
"(@|@@|\\$)?[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+|\\?(\\\\C-)?(\\\\M-)?."
- "|//=?|[-+*/<>%&^|=!]=|<<=?|>>=?|===|\\.{1,3}|::|[!=]~"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|//=?|[-+*/<>%&^|=!]=|<<=?|>>=?|===|\\.{1,3}|::|[!=]~"),
PATTERNS("bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
"[={}\"]|[^={}\" \t]+"),
PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
- "\\\\[a-zA-Z@]+|\\\\.|[a-zA-Z0-9\x80-\xff]+|[^[:space:]]"),
+ "\\\\[a-zA-Z@]+|\\\\.|[a-zA-Z0-9\x80-\xff]+"),
PATTERNS("cpp",
/* Jump targets or access declarations */
"!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:.*$\n"
@@ -113,8 +107,7 @@ PATTERNS("cpp",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
- "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
PATTERNS("csharp",
/* Keywords */
"!^[ \t]*(do|while|for|if|else|instanceof|new|return|switch|case|throw|catch|using)\n"
@@ -129,8 +122,7 @@ PATTERNS("csharp",
/* -- */
"[a-zA-Z_][a-zA-Z0-9_]*"
"|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
- "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"
- "|[^[:space:]]|[\x80-\xff]+"),
+ "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
{ "default", NULL, -1, { NULL, 0 } },
};
#undef PATTERNS

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