From 959e2e64a594e2fb8de2585078e31b07a8da6fc9 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 17 Jun 2009 16:26:06 +0200 Subject: [PATCH] avoid exponential regex match for java and objc function names In the old regex ^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\([^;]*)$ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ you can backtrack arbitrarily from [A-Za-z_0-9]* into [A-Za-z_], thus causing an exponential number of backtracks. Ironically it also causes the regex not to work as intended; for example "catch" can match the underlined part of the regex, the first repetition matching "c" and the second matching "atch". The replacement regex avoids this problem, because it makes sure that at least a space/tab is eaten on each repetition. In other words, a suffix of a repetition can never be a prefix of the next repetition. Signed-off-by: Paolo Bonzini Signed-off-by: Junio C Hamano --- userdiff.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/userdiff.c b/userdiff.c index d556da975..57529ae63 100644 --- a/userdiff.c +++ b/userdiff.c @@ -13,7 +13,8 @@ PATTERNS("html", "^[ \t]*(<[Hh][1-6][ \t].*>.*)$", "[^<>= \t]+|[^[:space:]]|[\x80-\xff]+"), PATTERNS("java", "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n" - "^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\\([^;]*)$", + "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$", + /* -- */ "[a-zA-Z_][a-zA-Z0-9_]*" "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?" "|[-+*/<>%&^|=!]=" @@ -25,7 +26,7 @@ PATTERNS("objc", /* Objective-C methods */ "^[ \t]*([-+][ \t]*\\([ \t]*[A-Za-z_][A-Za-z_0-9* \t]*\\)[ \t]*[A-Za-z_].*)$\n" /* C functions */ - "^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\\([^;]*)$\n" + "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$\n" /* Objective-C class/protocol definitions */ "^(@(implementation|interface|protocol)[ \t].*)$", /* -- */ -- 2.26.2