[PATCH xfree86] Allow negative conditions in "Match*" statements

[Oleh Nykyforchyn]

On Wed, 18 May 2011 14:08:27 +1000
Peter Hutterer <peter.hutterer at who-t.net> wrote:

> urgh. git diff please next time, i'm really not used to this format anymore.
> but yeah, makes sense now. thank you.
> pop the man page stuff in and I'll merge it in.

Final git diff version of the second patch:

xfree86: Allow negative conditions in "Match*" statements

Match statement syntax is extended to allow strings like:
"aaa,!a,bbb,!b,ccc,!c"
Match succeedes if an attribute matches aaa, bbb, or ccc, or
does not match neither a, b, or c.

Signed-off-by: Oleh Nykyforchyn <oleh.nyk at gmail.com>
---
 hw/xfree86/common/xf86Xinput.c |   24 ++++++++++++++++++++----
 1 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/hw/xfree86/common/xf86Xinput.c b/hw/xfree86/common/xf86Xinput.c
index c08ae53..88cf292 100644
--- a/hw/xfree86/common/xf86Xinput.c
+++ b/hw/xfree86/common/xf86Xinput.c
@@ -509,11 +509,27 @@ MatchAttrToken(const char *attr, struct list *patterns,
         char * const *cur;
         Bool match = FALSE;
 
-        for (cur = group->values; *cur; cur++)
-            if ((*compare)(attr, *cur) == 0) {
-                match = TRUE;
-                break;
+        for (cur = group->values; *cur; cur++) {
+            if (**cur == '!') {
+            /*
+             * A condition starting with '!' is NEGATIVE
+             * If it is matched, the match is rejected
+             */
+                if ((*compare)(attr, *cur+1) == 0)
+                    return FALSE;
+                else
+                    match = TRUE;
             }
+            else if ((*compare)(attr, *cur) == 0) {
+                    match = TRUE;
+                    break;
+            }
+        }
+        /*
+         * Hence we accept the match only if either a positive condition
+         * and all previous negative conditions succeed, or ALL (<>0)
+         * negative conditions are successful (i.e. not matched)
+         */
         if (!match)
             return FALSE;
     }
-- 
1.7.0.1



-- 
Oleh Nykyforchyn <oleh.nyk at gmail.com>