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authorPaolo Bonzini <bonzini@gnu.org>2009-06-17 14:26:06 (GMT)
committerJunio C Hamano <gitster@pobox.com>2009-06-18 16:52:10 (GMT)
commit959e2e64a594e2fb8de2585078e31b07a8da6fc9 (patch)
treebd57636123d4d79e88965e88f4eafebaa5434bee /userdiff.c
parent9b7dc7183528d42c46786a0be1acc58d4cd1f47a (diff)
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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 <bonzini@gnu.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'userdiff.c')
-rw-r--r--userdiff.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/userdiff.c b/userdiff.c
index d556da9..57529ae 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].*)$",
/* -- */