Revert "Rewrite the entire internal signal handling/wakeup."

[cubemap] / thread.h

diff --git a/thread.h b/thread.h
index 12aa133d82f77781e6de0b3273e8dc0128232d76..26e648e5332d6a3016d0ec59d4a58b58b09033a8 100644 (file)
--- a/thread.h
+++ b/thread.h
@@ -1,19 +1,12 @@
 #ifndef _THREAD_H
 #define _THREAD_H
 
-#include <signal.h>
 #include <pthread.h>
 
-struct timespec;
-
-// A thread class with start/stop and signal functionality.
-//
-// SIGUSR1 is blocked during execution of do_work(), so that you are guaranteed
-// to receive it when doing wait_for_activity(), and never elsewhere. This means
-// that you can test whatever status flags you'd want before calling
-// wait_for_activity(), and then be sure that it actually returns immediately
-// if a SIGUSR1 (ie., wakeup()) happened, even if it were sent between your test
-// and the wait_for_activity() call.
+// A rather generic thread class with start/stop functionality.
+// NOTE: stop is somewhat racy (there's no guaranteed breakout from syscalls),
+// since signals don't stick. We'll need to figure out something more
+// intelligent later, probably based on sending a signal to an fd.
 
 class Thread {
 public:
@@ -22,38 +15,21 @@ public:
        void stop();
 
 protected:
-       // Recovers the this pointer, blocks SIGUSR1, and calls do_work().
+       // Recovers the this pointer, and calls do_work().
        static void *do_work_thunk(void *arg);
 
        virtual void do_work() = 0;
 
-       // Waits until there is activity of the given type on <fd> (or an error),
-       // or until a wakeup. Returns true if there was actually activity on
-       // the file descriptor.
-       //
-       // If fd is -1, wait until a wakeup or timeout.
-       // if timeout_ts is NULL, there is no timeout.
-       bool wait_for_activity(int fd, short events, const timespec *timeout_ts);
-
-       // Wait until a wakeup.
-       void wait_for_wakeup(const timespec *timeout_ts) { wait_for_activity(-1, 0, timeout_ts); }
-
-       // Make wait_for_activity() return.
-       void wakeup();
+       volatile bool should_stop;
 
-       bool should_stop();
-
-       // The signal set as it were before we blocked SIGUSR1.
-       sigset_t sigset_without_usr1_block;
+       // A pipe that you can poll on if you want to see when should_stop
+       // has been set to true; stop() will write a single byte to the pipe
+       // and then close the other end.
+       int stop_fd_read;
 
 private:
        pthread_t worker_thread;
-
-       // Protects should_stop_status.
-       pthread_mutex_t should_stop_mutex;
-
-       // If this is set, the thread should return as soon as possible from do_work().
-       bool should_stop_status;
+       int stop_fd_write;
 };
 
 #endif  // !defined(_THREAD_H)