On Jan 27, 2008 12:25 PM, Victor Lowther <[EMAIL PROTECTED]> wrote:
> Adds a generic locking mechanism built around directory creation/removal.
The timeout support in spin_lock doesn't seem like it would work.
+# spin waiting for the lock with optional timeout.
+# return once we have it, or the timeout has expired
+spin_lock()
+{
+ # $1 = directory to use as the lock directory
+ # $2 = optional timeout
+ local elapsed=0
+ while ! try_lock $1; do
+ sleep 1;
+ [ "x$2" != "x" ] && [ $(( $elapsed == $2 )) -ne 0 ] && return 1
+ done
+}
$elapsed never seems to be incremented. I also don't believe that you
want to sleep before checking the timeout. This results in a `sleep 1'
even if you haven't specified a timeout; i.e., you want to return
immediately. Personally, I would write it like this (trying not to let
too much personal style seep in):
spin_lock()
{
local elapsed=0
local timeout=${2:-0}
while ! try_lock $1; do
[ $timeout -le $elapsed ] && return 1
elapsed=$(( $elapsed + 1 ))
sleep 1
done
}
What do you think?
--
Dan
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