Merge lp:~mixxxdevelopers/mixxx/fixes_midi_burnout into lp:~mixxxdevelopers/mixxx/trunk

[William Good]

Fixes bug https://bugs.launchpad.net/mixxx/+bug/990992, methodology/results at https://bugs.launchpad.net/mixxx/+bug/990992/comments/9

=== modified file 'mixxx/build/depends.py'
--- mixxx/build/depends.py	2012-05-19 00:27:41 +0000
+++ mixxx/build/depends.py	2012-05-21 17:49:20 +0000
@@ -581,6 +581,7 @@
                    "tapfilter.cpp",
 
                    "util/pa_ringbuffer.c",
+                   "sleepableqthread.cpp",
 
                    # Add the QRC file which compiles in some extra resources
                    # (prefs icons, etc.)

=== modified file 'mixxx/src/controllers/controller.h'
--- mixxx/src/controllers/controller.h	2012-04-29 01:40:37 +0000
+++ mixxx/src/controllers/controller.h	2012-05-21 17:49:20 +0000
@@ -122,8 +122,9 @@
   private slots:
     virtual int open() = 0;
     virtual int close() = 0;
-    // Requests that the device poll if it is a polling device.
-    virtual void poll() { }
+    // Requests that the device poll if it is a polling device. Returns true
+    // if events were handled.
+    virtual bool poll() { return false; }
 
   private:
     // This must be reimplemented by sub-classes desiring to send raw bytes to a

=== modified file 'mixxx/src/controllers/controllermanager.cpp'
--- mixxx/src/controllers/controllermanager.cpp	2012-05-01 14:45:33 +0000
+++ mixxx/src/controllers/controllermanager.cpp	2012-05-21 17:49:20 +0000
@@ -7,6 +7,7 @@
 
 #include <QSet>
 
+#include "sleepableqthread.h"
 #include "controllers/controllermanager.h"
 #include "controllers/defs_controllers.h"
 #include "controllers/controllerlearningeventfilter.h"
@@ -246,11 +247,15 @@
 }
 
 void ControllerManager::pollDevices() {
+    bool eventsProcessed(false);
     foreach (Controller* pDevice, m_controllers) {
         if (pDevice->isOpen() && pDevice->isPolling()) {
-            pDevice->poll();
+            eventsProcessed = pDevice->poll() || eventsProcessed;
         }
     }
+    // if we didn't process anything, sleep a bit to avoid burning/hogging
+    // cpu cycles
+    if (!eventsProcessed) SleepableQThread::msleep(1);
 }
 
 QList<QString> ControllerManager::getPresetList(QString extension) {

=== modified file 'mixxx/src/controllers/midi/portmidicontroller.cpp'
--- mixxx/src/controllers/midi/portmidicontroller.cpp	2012-04-24 05:42:04 +0000
+++ mixxx/src/controllers/midi/portmidicontroller.cpp	2012-05-21 17:49:20 +0000
@@ -134,18 +134,18 @@
     return 0;
 }
 
-void PortMidiController::poll() {
+bool PortMidiController::poll() {
     // Poll the controller for new data
     int numEvents = 0;
 
     if (m_pInputStream) {
         PmError gotEvents = Pm_Poll(m_pInputStream);
         if (gotEvents == FALSE) {
-            return;
+            return false;
         }
         if (gotEvents < 0) {
             qWarning() << "PortMidi error:" << Pm_GetErrorText(gotEvents);
-            return;
+            return false;
         }
 
         numEvents = Pm_Read(m_pInputStream, m_midiBuffer, MIXXX_PORTMIDI_BUFFER_LEN);
@@ -198,6 +198,7 @@
             m_cReceiveMsg_index = 0;
         }
     }
+    return numEvents > 0;
 }
 
 void PortMidiController::send(unsigned int word) {

=== modified file 'mixxx/src/controllers/midi/portmidicontroller.h'
--- mixxx/src/controllers/midi/portmidicontroller.h	2012-04-24 07:19:23 +0000
+++ mixxx/src/controllers/midi/portmidicontroller.h	2012-05-21 17:49:20 +0000
@@ -36,7 +36,7 @@
   private slots:
     virtual int open();
     virtual int close();
-    virtual void poll();
+    virtual bool poll();
 
   private:
     void send(unsigned int word);

=== added file 'mixxx/src/sleepableqthread.cpp'
--- mixxx/src/sleepableqthread.cpp	1970-01-01 00:00:00 +0000
+++ mixxx/src/sleepableqthread.cpp	2012-05-21 17:49:20 +0000
@@ -0,0 +1,8 @@
+// sleepableqthread.cpp
+// Created May 21, 2012 by Bill Good <bkgood at gmail dot com>
+//
+// This is just a dummy file meant to be shoved in the build list so that moc
+// runs on the class and linker errors are avoided.
+
+#include "sleepableqthread.h"
+

=== added file 'mixxx/src/sleepableqthread.h'
--- mixxx/src/sleepableqthread.h	1970-01-01 00:00:00 +0000
+++ mixxx/src/sleepableqthread.h	2012-05-21 17:49:20 +0000
@@ -0,0 +1,26 @@
+// sleepableqthread.h
+// Created May 21, 2012 by Bill Good <bkgood at gmail dot com>
+
+#include <QThread>
+
+// Subclass of QThread exposing static sleep methods. Qt developers know
+// better than us and therefore made these methods protected but I'm a
+// rebel.
+class SleepableQThread : public QThread {
+    Q_OBJECT;
+    Q_DISABLE_COPY(SleepableQThread);
+public:
+    explicit SleepableQThread(QObject *parent = NULL) : QThread(parent) { }
+    virtual ~SleepableQThread() { }
+    static void sleep(unsigned long secs) {
+        QThread::sleep(secs);
+    }
+
+    static void msleep(unsigned long msecs) {
+        QThread::msleep(msecs);
+    }
+
+    static void usleep(unsigned long usecs) {
+        QThread::usleep(usecs);
+    }
+};