fix endless-loop-at-shutdown bug now that abstract UI request buffers are used

[ardour.git] / libs / pbd / base_ui.cc

diff --git a/libs/pbd/base_ui.cc b/libs/pbd/base_ui.cc
index 94d039ba8633aef20c4d9f462527831a7e996de6..c56fb8f4fe33eeaa1a5fe15fbcb0f259a858ca15 100644 (file)
--- a/libs/pbd/base_ui.cc
+++ b/libs/pbd/base_ui.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2000-2007 Paul Davis 
+    Copyright (C) 2000-2007 Paul Davis
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -19,49 +19,48 @@
 
 #include <cstring>
 #include <stdint.h>
+#ifdef COMPILER_MSVC
+#include <io.h>      // Microsoft's nearest equivalent to <unistd.h>
+#else
 #include <unistd.h>
+#endif
 #include <fcntl.h>
-#include <errno.h>
+#include <cerrno>
+#include <cstring>
 
-#include <pbd/base_ui.h>
-#include <pbd/error.h>
-#include <pbd/compose.h>
-#include <pbd/failed_constructor.h>
+#include "pbd/base_ui.h"
+#include "pbd/debug.h"
+#include "pbd/pthread_utils.h"
+#include "pbd/error.h"
+#include "pbd/compose.h"
+#include "pbd/failed_constructor.h"
 
 #include "i18n.h"
 
+#include "pbd/debug.h"
+
 using namespace std;
 using namespace PBD;
-       
-uint32_t BaseUI::rt_bit = 1;
+using namespace Glib;
+
+uint64_t BaseUI::rt_bit = 1;
 BaseUI::RequestType BaseUI::CallSlot = BaseUI::new_request_type();
+BaseUI::RequestType BaseUI::Quit = BaseUI::new_request_type();
 
-BaseUI::BaseUI (string str, bool with_signal_pipe)
-       : _name (str)
+BaseUI::BaseUI (const string& loop_name)
+       : EventLoop (loop_name)
+       , m_context(MainContext::get_default())
+       , run_loop_thread (0)
+       , request_channel (true)
 {
-       /* odd pseudo-singleton semantics */
-
        base_ui_instance = this;
+       request_channel.set_receive_handler (sigc::mem_fun (*this, &BaseUI::request_handler));
 
-       signal_pipe[0] = -1;
-       signal_pipe[1] = -1;
-
-       if (with_signal_pipe) {
-               if (setup_signal_pipe ()) {
-                       throw failed_constructor ();
-               }
-       }
+       /* derived class must set _ok */
 }
 
 BaseUI::~BaseUI()
 {
-       if (signal_pipe[0] >= 0) {
-               close (signal_pipe[0]);
-       } 
-
-       if (signal_pipe[1] >= 0) {
-               close (signal_pipe[1]);
-       } 
 }
 
 BaseUI::RequestType
@@ -77,32 +76,87 @@ BaseUI::new_request_type ()
        return rt;
 }
 
-int
-BaseUI::setup_signal_pipe ()
+void
+BaseUI::main_thread ()
+{
+       DEBUG_TRACE (DEBUG::EventLoop, string_compose ("%1: event loop running in thread %2\n", event_loop_name(), pthread_name()));
+       set_event_loop_for_thread (this);
+       thread_init ();
+       _main_loop->get_context()->signal_idle().connect (sigc::mem_fun (*this, &BaseUI::signal_running));
+       _main_loop->run ();
+}
+
+bool
+BaseUI::signal_running ()
+{
+       Glib::Threads::Mutex::Lock lm (_run_lock);
+       _running.signal ();
+
+       return false; // don't call it again
+}
+
+void
+BaseUI::run ()
 {
-       /* setup the pipe that other threads send us notifications/requests
-          through.
+       /* to be called by UI's that need/want their own distinct, self-created event loop thread.
        */
 
-       if (pipe (signal_pipe)) {
-               error << string_compose (_("%1-UI: cannot create error signal pipe (%2)"), _name, std::strerror (errno))
-                     << endmsg;
+       m_context = MainContext::create();
+       _main_loop = MainLoop::create (m_context);
+       attach_request_source ();
 
-               return -1;
+       Glib::Threads::Mutex::Lock lm (_run_lock);
+       run_loop_thread = Glib::Threads::Thread::create (mem_fun (*this, &BaseUI::main_thread));
+       _running.wait (_run_lock);
+}
+
+void
+BaseUI::quit ()
+{
+       if (_main_loop && _main_loop->is_running()) {
+               _main_loop->quit ();
+               run_loop_thread->join ();
        }
+}
 
-       if (fcntl (signal_pipe[0], F_SETFL, O_NONBLOCK)) {
-               error << string_compose (_("%1-UI: cannot set O_NONBLOCK on signal read pipe (%2)"), _name, std::strerror (errno))
-                     << endmsg;
-               return -1;
+bool
+BaseUI::request_handler (Glib::IOCondition ioc)
+{
+       /* check the request pipe */
+
+       if (ioc & ~IO_IN) {
+               _main_loop->quit ();
        }
 
-       if (fcntl (signal_pipe[1], F_SETFL, O_NONBLOCK)) {
-               error << string_compose (_("%1-UI: cannot set O_NONBLOCK on signal write pipe (%2)"), _name, std::strerror (errno))
-                     << endmsg;
-               return -1;
+       if (ioc & IO_IN) {
+               request_channel.drain ();
+
+               /* there may been an error. we'd rather handle requests first,
+                  and then get IO_HUP or IO_ERR on the next loop.
+               */
+
+               /* handle requests */
+
+               DEBUG_TRACE (DEBUG::EventLoop, "BaseUI::request_handler\n");
+               handle_ui_requests ();
        }
 
-       return 0;
+       return true;
 }
 
+void
+BaseUI::signal_new_request ()
+{
+       DEBUG_TRACE (DEBUG::EventLoop, "BaseUI::signal_new_request\n");
+       request_channel.wakeup ();
+}
+
+/**
+ * This method relies on the caller having already set m_context
+ */
+void
+BaseUI::attach_request_source ()
+{
+       DEBUG_TRACE (DEBUG::EventLoop, "BaseUI::attach_request_source\n");
+       request_channel.attach (m_context);
+}