annotate pyvamp-main.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?

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/**
 * This Vamp plugin is a wrapper for Python Scripts. (VamPy)
 * Centre for Digital Music, Queen Mary, University of London.
 * Copyright 2008, George Fazekas.
 */

#include <Python.h>
#include "vamp/vamp.h"
#include "vamp-sdk/PluginAdapter.h"
#include "PyPlugScanner.h"
#include "PyPlugin.h"

#ifdef _WIN32
#define pathsep ('\\')
#include <windows.h>
#include <tchar.h>
#else 
#define pathsep ('/')
#include <dirent.h>
#include <dlfcn.h>
#endif

using std::cerr;
using std::endl;
using std::string;
using std::vector;

//volatile bool mutex = false;
static int adinstcount;

class PyPluginAdapter : public Vamp::PluginAdapterBase
{
public: 
    PyPluginAdapter(std::string pyPlugId, PyObject* pyClass) :
        PluginAdapterBase(),
        m_plug(pyPlugId),		
        m_pyClass(pyClass)
    { 
        cerr << "PyPluginAdapter:ctor:"<< adinstcount << ": " << m_plug << endl; 
        adinstcount++;
        m_instanceCount = 0;
    }
    
    ~PyPluginAdapter() 
    {
    }
    
protected:
    Vamp::Plugin *createPlugin(float inputSampleRate)
    {
        try {
            PyPlugin *plugin = new PyPlugin(m_plug, inputSampleRate, m_pyClass);
            m_instanceCount++;
            return plugin;
        } catch (...) {
            cerr << "PyPluginAdapter::createPlugin: Failed to construct PyPlugin" << endl;
            return 0;
        }
    }
    
    std::string m_plug;
    bool m_haveInitialized;
    PyObject *m_pyClass;
    int m_instanceCount;
};


static std::vector<PyPluginAdapter *> adapters;
static bool haveScannedPlugins = false;

static bool tryPreload(string name)
{
    cerr << "Trying to load Python interpreter library \"" << name << "\"...";
#ifdef _WIN32
    void *lib = LoadLibrary(name.c_str());
    if (!lib) {
        cerr << " failed" << endl;
        return false;
    }
#else
    void *lib = dlopen(name.c_str(), RTLD_NOW | RTLD_GLOBAL);
    if (!lib) {
        cerr << " failed" << endl;
        return false;
    }
#endif
    cerr << " succeeded" << endl;
    return true;
}

static bool preloadPython()
{
#ifdef _WIN32
    // this doesn't seem to be necessary at all on Windows
    return true;
#endif

    string pyver = Py_GetVersion();
    int dots = 2;
    string shortver;
    for (size_t i = 0; i < pyver.length(); ++i) {
        if (pyver[i] == '.') {
            if (--dots == 0) {
                shortver = pyver.substr(0, i);
                break;
            }
        }
    }
    cerr << "Short version: " << shortver << endl;

    vector<string> pfxs;
    pfxs.push_back("");
    pfxs.push_back(string(Py_GetExecPrefix()) + "/lib/");
    pfxs.push_back(string(Py_GetExecPrefix()) + "/");
    pfxs.push_back("/usr/lib/");
    pfxs.push_back("/usr/local/lib/");
    char buffer[5];

    // hahaha! grossness is like a brother to us
#ifdef __APPLE__
    for (size_t pfxidx = 0; pfxidx < pfxs.size(); ++pfxidx) {
        for (int minor = 8; minor >= 0; --minor) {
            sprintf(buffer, "%d", minor);
            if (tryPreload(pfxs[pfxidx] + string("libpython") + shortver + ".dylib." + buffer)) return true;
        }
        if (tryPreload(pfxs[pfxidx] + string("libpython") + shortver + ".dylib")) return true;
        if (tryPreload(pfxs[pfxidx] + string("libpython.dylib"))) return true;
    }
#else
    for (size_t pfxidx = 0; pfxidx < pfxs.size(); ++pfxidx) {
        for (int minor = 8; minor >= 0; --minor) {
            sprintf(buffer, "%d", minor);
            if (tryPreload(pfxs[pfxidx] + string("libpython") + shortver + ".so." + buffer)) return true;
        }
        if (tryPreload(pfxs[pfxidx] + string("libpython") + shortver + ".so")) return true;
        if (tryPreload(pfxs[pfxidx] + string("libpython.so"))) return true;
    }
#endif
        
    return false;
}
    

const VampPluginDescriptor 
*vampGetPluginDescriptor(unsigned int version,unsigned int index)
{	
    if (version < 1) return 0;

	int isPythonInitialized = Py_IsInitialized();
	cerr << "# isPythonInitialized: " << isPythonInitialized << endl;
	cerr << "# haveScannedPlugins: " << haveScannedPlugins << endl;

	if (!haveScannedPlugins) {

		if (!isPythonInitialized) {

			if (!preloadPython()) {
                            cerr << "Warning: Could not preload Python." 
                                 << " Dynamic loading in scripts will fail." << endl;
                        }

/*
			void *pylib = 0; 
			
			cerr << "Loading Python Interpreter at: " << pythonPath << endl;
			//Preloading the binary allows the load of shared libs 
			//TODO: check how to do RTLD_NOW on Windows
#ifdef _WIN32
			pylib = LoadLibrary(pythonPath.c_str());
#else			
			pylib = dlopen(pythonPath.c_str(), RTLD_NOW|RTLD_GLOBAL);
#endif			
			if (!pylib) cerr << "Warning: Could not preload Python." 
						<< " Dynamic loading in scripts will fail." << endl;
*/
			Py_Initialize();
                        cerr << "# isPythonInitialized after initialize: " << Py_IsInitialized() << endl;
	 		PyEval_InitThreads();			
		} else {
			//Py_InitializeEx(1);
		}

		vector<string> pyPlugs;
		vector<string> pyPath;
		vector<PyObject *> pyClasses;
		static PyPlugScanner *scanner;
		
		//Scanning Plugins
		cerr << "Scanning PyPlugins" << endl;
		scanner = PyPlugScanner::getInstance();
		pyPath=scanner->getAllValidPath();
		//add this as extra path for development
		//pyPath.push_back("/Users/Shared/Development/vamp-experiments");
		scanner->setPath(pyPath);
		pyPlugs = scanner->getPyPlugs();
		cerr << "Found " << pyPlugs.size() << " Scripts ...OK" << endl;
		//TODO: this will support multiple classes per script
		pyClasses = scanner->getPyClasses();
		cerr << "Found " << pyClasses.size() << " Classes ...OK" << endl;

		for (size_t i = 0; i < pyPlugs.size(); ++i) {
			adapters.push_back( new PyPluginAdapter(pyPlugs[i],pyClasses[i]));
		} 
		haveScannedPlugins=true;		
		
	}

	cerr << "Accessing adapter index: " << index << " (adapters: " << adapters.size() << ")" << endl;
	if (index<adapters.size()) {
		const VampPluginDescriptor *tmp = adapters[index]->getDescriptor();
		return tmp;
	} else return 0;

	
}