[cairo] Static caches and thread-safety

[Carl Worth]

On Thu, 11 Nov 2004 13:10:15 -0800, Bill Spitzak wrote:
> Sorry, attached the wrong version. This one uses the recursive lock on Linux 
> if it can:

I think in this case we don't even need a recursive lock. But I had
already found the _GNU_SOURCE thing in order to get an error-checking
mutex for when compiling with assertions enabled. That seems useful.

>   /* STOOPID WINDOWS! This next line is not thread-safe. It would help
>      if there were a compile-time initializer for the semaphore. Otherwise
>      the only thread-safe solution is to initialize this code on startup
>      when you know there are no other threads... */
>   if (!initialized) {initialized=true; InitializeCriticalSection(&cs);}

Ugh. Is that really the best one can do there?

On second thought, don't tell me. I really don't want to know.

I'm half tempted to move the caches down into cairo_t and encourage
users to clone from a single call to cairo_create if they want to get
all the sharing benefits...

Keeping locking out of cairo definitely seems appealing. And I wouldn't
guess that it would be common for less-informed users to want to make
lots of simultaneous cairo_t objects. Stupid?

Thread-local storage?

Nothing seems perfectly clean here. Dirty, dirty...

-Carl