[beast: 40/95] BSE: use EventFd for Sequencer wakeups

[Tim Janik <timj src gnome org>]

commit 50cc3e829b96c2149fa6b43e6d0730eb15b281f7
Author: Tim Janik <timj gnu org>
Date:   Tue Mar 19 01:05:38 2013 +0100

    BSE: use EventFd for Sequencer wakeups

 bse/bsesequencer.cc |   33 +++++++--------------------------
 bse/bsesequencer.hh |    4 +++-
 2 files changed, 10 insertions(+), 27 deletions(-)
---
diff --git a/bse/bsesequencer.cc b/bse/bsesequencer.cc
index d8bc498..48b3fd4 100644
--- a/bse/bsesequencer.cc
+++ b/bse/bsesequencer.cc
@@ -10,8 +10,6 @@
 #include "bsemain.hh"
 #include "bseieee754.hh"
 #include <sys/poll.h>
-#include <unistd.h>
-#include <fcntl.h>
 #include <errno.h>
 #include <string.h>
 #include <vector>
@@ -26,19 +24,8 @@ using Rapicorn::ThreadInfo; // FIXME
 
 Sequencer              *Sequencer::singleton_ = NULL;
 Mutex                   Sequencer::sequencer_mutex_;
-static int              sequencer_wake_up_pipe[2] = { -1, -1 };
 static ThreadInfo      *sequencer_thread_self = NULL;
 
-void
-Sequencer::wakeup ()
-{
-  uint8 wake_up_message = 'W';
-  int err;
-  do
-    err = write (sequencer_wake_up_pipe[1], &wake_up_message, 1);
-  while (err < 0 && errno == EINTR);
-}
-
 class Sequencer::PollPool {
 public:
   struct IOWatch {
@@ -204,12 +191,12 @@ Sequencer::remove_io_watch (BseIOWatch watch_func, void *watch_data)
 bool
 Sequencer::pool_poll_Lm (gint timeout_ms)
 {
-  guint n_pfds = poll_pool_->get_n_pfds() + 1;  /* one for the wake-up pipe */
+  uint n_pfds = poll_pool_->get_n_pfds() + 1;   // one for the wake-up event_fd_
   GPollFD *pfds = g_newa (GPollFD, n_pfds);
-  pfds[0].fd = sequencer_wake_up_pipe[0];
+  pfds[0].fd = event_fd_.inputfd();
   pfds[0].events = G_IO_IN;
   pfds[0].revents = 0;
-  poll_pool_->fill_pfds (n_pfds - 1, pfds + 1); /* rest used for io watch array */
+  poll_pool_->fill_pfds (n_pfds - 1, pfds + 1); // rest used for io watch array
   BSE_SEQUENCER_UNLOCK();
   int result = poll ((struct pollfd*) pfds, n_pfds, timeout_ms);
   if (result < 0 && errno != EINTR)
@@ -217,9 +204,7 @@ Sequencer::pool_poll_Lm (gint timeout_ms)
   BSE_SEQUENCER_LOCK();
   if (result > 0 && pfds[0].revents)
     {
-      guint8 buffer[256];
-      const size_t unused = read (sequencer_wake_up_pipe[0], buffer, 256);      // eat wake up message
-      (void) unused;
+      event_fd_.flush();                        // eat wake up message
       result -= 1;
     }
   if (result > 0)
@@ -550,14 +535,10 @@ Sequencer::Sequencer() :
   stamp_ = Bse::TickStamp::current();
   assert (stamp_ > 0);
 
-  if (pipe (sequencer_wake_up_pipe) < 0)
-    g_error ("failed to create sequencer wake-up pipe: %s", strerror (errno));
-  long flags = fcntl (sequencer_wake_up_pipe[0], F_GETFL, 0);
-  fcntl (sequencer_wake_up_pipe[0], F_SETFL, O_NONBLOCK | flags);
-  flags = fcntl (sequencer_wake_up_pipe[1], F_GETFL, 0);
-  fcntl (sequencer_wake_up_pipe[1], F_SETFL, O_NONBLOCK | flags);
-
   poll_pool_ = new PollPool;
+
+  if (event_fd_.open() != 0)
+    g_error ("failed to create sequencer wake-up pipe: %s", strerror (errno));
 }
 
 void
diff --git a/bse/bsesequencer.hh b/bse/bsesequencer.hh
index 52d8bd2..48063a7 100644
--- a/bse/bsesequencer.hh
+++ b/bse/bsesequencer.hh
@@ -7,6 +7,7 @@ namespace Bse {
 
 using Rapicorn::Mutex;    // FIXME
 using Rapicorn::Cond;    // FIXME
+using Rapicorn::EventFd;    // FIXME
 
 /** Note and MIDI sequencer.
  * The sequencer processes notes from parts and MIDI input and generates events for the synthesis engine.
@@ -19,6 +20,7 @@ class Sequencer {
   SfiRing   *songs_;
   Cond       watch_cond_;
   PollPool  *poll_pool_;
+  EventFd    event_fd_;
   std::thread thread_;
 private:
   void          sequencer_thread ();
@@ -35,12 +37,12 @@ private:
 protected:
   static void   _init_threaded  ();
 public:
-  void          wakeup          ();
   void          add_io_watch    (uint n_pfds, const GPollFD *pfds, BseIOWatch watch_func, void *watch_data);
   void          remove_io_watch (BseIOWatch watch_func, void *watch_data);
   void          start_song     (BseSong *song, uint64 start_stamp);
   void          remove_song    (BseSong *song);
   bool          thread_lagging  (uint n_blocks);
+  void          wakeup          ()      { event_fd_.wakeup(); }
   static Mutex& sequencer_mutex ()      { return sequencer_mutex_; }
   static Sequencer& instance    ()      { return *singleton_; }
 };