diff PyPlugin.cpp @ 24:7d28bed0864e

* Rearrange Python plugin construction.

  Formerly, the PyPluginAdapter has retained a single plugin instance pointer
  for each plugin found, and its createPlugin method has simply returned a new
  PyPlugin object wrapping the same instance pointer.  This has a couple of
  negative consequences:
   - Because construction of the actual Python instance occurred before the
     wrapper was constructed, it was not possible to pass arguments (i.e.
     the sample rate) from the wrapper constructor to the Python plugin
     instance constructor -- they had to be passed later, to initialise,
     disadvantaging those plugins that would like to use the sample rate
     for parameter & step/block size calculations etc
   - Because there was only a single Python plugin instance, it was not
     possible to run more than one instance at once with any isolation

  This rework instead stores the Python class pointer (rather than instance
  pointer) in the PyPluginAdapter, and each PyPlugin wrapper instance creates
  its own Python plugin instance.  What could possibly go wrong?

--- a/PyPlugin.cpp	Thu Jul 16 13:19:20 2009 +0000
+++ b/PyPlugin.cpp	Mon Aug 17 15:22:06 2009 +0000
@@ -75,12 +75,12 @@
 Mutex PyPlugin::m_pythonInterpreterMutex;
 static bool isMapInitialised = false;
 
-PyPlugin::PyPlugin(std::string pluginKey,float inputSampleRate, PyObject *pyInstance) :
-    Plugin(inputSampleRate),
-	m_pyInstance(pyInstance),
+PyPlugin::PyPlugin(std::string pluginKey, float inputSampleRate, PyObject *pyClass) :
+	Plugin(inputSampleRate),
+	m_pyClass(pyClass),
 	m_stepSize(0),
 	m_blockSize(0),
-    m_channels(0),
+	m_channels(0),
 	m_plugin(pluginKey),
 	m_class(pluginKey.substr(pluginKey.rfind(':')+1,pluginKey.size()-1)),
 	m_path((pluginKey.substr(0,pluginKey.rfind(pathsep)))),
@@ -88,14 +88,29 @@
 	m_pyProcess(NULL),
 	m_inputDomain(TimeDomain)
 {	
+	// Create an instance
+	PyObject *pyInputSampleRate = PyFloat_FromDouble(inputSampleRate);
+	PyObject *args = PyTuple_Pack(1, pyInputSampleRate);
+
+	m_pyInstance = PyObject_CallObject(m_pyClass, args);
+
+	if (!m_pyInstance) {
+		cerr << "PyPlugin::PyPlugin: Failed to create Python plugin instance for key \"" << pluginKey << "\" (is the 1-arg class constructor from sample rate correctly provided?)" << endl;
+		throw std::string("Constructor failed");
+	}
+	
+	Py_DECREF(args);
+	Py_DECREF(pyInputSampleRate);
 }
 
 PyPlugin::~PyPlugin()
 {
+	if (m_pyInstance) Py_DECREF(m_pyInstance);
+
 	Py_CLEAR(m_pyProcess);
 #ifdef _DEBUG
 	cerr << "PyPlugin::PyPlugin:" << m_class 
-	<< " Instance deleted." << endl;
+	     << " Instance deleted." << endl;
 #endif
 }
 
@@ -222,7 +237,9 @@
 int
 PyPlugin::getPluginVersion() const
 {
-    return 2;
+	//!!! implement
+
+	return 2;
 }
 
 string
@@ -252,7 +269,8 @@
 		rString=PyString_AsString(pyString);
 		Py_CLEAR(pyString);
 	}
-    return rString;
+
+	return rString;
 }
 
 
@@ -264,8 +282,8 @@
 	cerr << "[call] " << method << endl;
 	
 	//placing Mutex before these calls causes deadlock
-    if (channels < getMinChannelCount() ||
-	channels > getMaxChannelCount()) return false;
+	if (channels < getMinChannelCount() ||
+	    channels > getMaxChannelCount()) return false;
 	
 	m_inputDomain = getInputDomain();
 
@@ -300,45 +318,42 @@
 		m_processType = not_implemented;
 		m_pyProcess = NULL;		
 		cerr << "Warning: Python plugin [" << m_class << "::" << method 
-		<< "] No process implementation found. Plugin will do nothing." << endl;
+		     << "] No process implementation found. Plugin will do nothing." << endl;
 	}
 
-	
-		//Check if the method is implemented in Python else return false
-		if (PyObject_HasAttrString(m_pyInstance,method)) {
+	//Check if the method is implemented in Python else return false
+	if (PyObject_HasAttrString(m_pyInstance,method)) {
    			
-			PyObject *pyMethod = PyString_FromString(method);
-			PyObject *pyChannels = PyInt_FromSsize_t((Py_ssize_t)channels);
-			PyObject *pyStepSize = PyInt_FromSsize_t((Py_ssize_t)m_stepSize);
-			PyObject *pyBlockSize = PyInt_FromSsize_t((Py_ssize_t)blockSize);
-			PyObject *pyInputSampleRate = PyFloat_FromDouble((double)m_inputSampleRate);
-			
-			//Call the method
-			PyObject *pyBool = 
-			PyObject_CallMethodObjArgs(m_pyInstance,pyMethod,pyChannels,pyStepSize,pyBlockSize,pyInputSampleRate,NULL);
+		PyObject *pyMethod = PyString_FromString(method);
+		PyObject *pyChannels = PyInt_FromSsize_t((Py_ssize_t)channels);
+		PyObject *pyStepSize = PyInt_FromSsize_t((Py_ssize_t)m_stepSize);
+		PyObject *pyBlockSize = PyInt_FromSsize_t((Py_ssize_t)blockSize);
+		//Call the method
+		PyObject *pyBool = 
+			PyObject_CallMethodObjArgs(m_pyInstance,pyMethod,pyChannels,pyStepSize,pyBlockSize,NULL);
 						
-			Py_DECREF(pyMethod);
-			Py_DECREF(pyChannels);
-			Py_DECREF(pyStepSize);
-			Py_DECREF(pyBlockSize);
-			Py_DECREF(pyInputSampleRate);
+		Py_DECREF(pyMethod);
+		Py_DECREF(pyChannels);
+		Py_DECREF(pyStepSize);
+		Py_DECREF(pyBlockSize);
 
-			//Check return value
-			if (PyErr_Occurred() || !PyBool_Check(pyBool)) {
-				PyErr_Print(); PyErr_Clear();
-				Py_CLEAR(pyBool);
-				cerr << "ERROR: In Python plugin [" << m_class << "::" << method 
-				<< "] Expected Bool return value." << endl;
-				return false;
-			}
-
-			if (pyBool == Py_True) {  
-				Py_CLEAR(pyBool); 
-				return true;
-			} else {
-				Py_CLEAR(pyBool); 
-				return false;}								
-		} 
+		//Check return value
+		if (PyErr_Occurred() || !PyBool_Check(pyBool)) {
+			PyErr_Print(); PyErr_Clear();
+			Py_CLEAR(pyBool);
+			cerr << "ERROR: In Python plugin [" << m_class << "::" << method 
+			     << "] Expected Bool return value." << endl;
+			return false;
+		}
+		
+		if (pyBool == Py_True) {  
+			Py_CLEAR(pyBool); 
+			return true;
+		} else {
+			Py_CLEAR(pyBool); 
+			return false;
+		}
+	} 
     	return false;
 }