JVM.h

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// -*- mode: c++; indent-tabs-mode: nil; c-basic-offset: 4; coding: iso-8859-1; -*-

/*
ACT-CV - Machine Vision for Cognitive Modeling
Copyright (c) 2008 Marc Halbruegge

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
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef JVM_H_
#define JVM_H_

#include <jni.h>
#include <map>

#if HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef __GNUC__
#ifdef __APPLE__
// os x specific stuff
#include <sys/types.h>
#include <unistd.h>
#include <unistd.h>
#include <errno.h>
#include <sys/syscall.h>

#else
// linux specific stuff
#include <sys/types.h>
#include <unistd.h>
#include <linux/unistd.h>
#include <errno.h>
#include <sys/syscall.h>
#endif
#endif

#ifdef _WINDOWS
# include <windows.h>
#else
// linux
# include <dlfcn.h>
# define __stdcall
#endif

class JVM {
    JavaVMInitArgs vm_args; 
    JavaVMOption options[3]; 

    std::map<int,JNIEnv*> threadSpecificEnvs;

    bool mustDestroyVM;

#ifdef _WINDOWS
    HINSTANCE jvmInstance;
#else
    void* jvmInstance;
#endif

    jint (__stdcall *jniCreateJavaVM)(JavaVM **, void **, void *);

    jint (__stdcall *jniGetCreatedJavaVMs)(JavaVM **, jsize, jsize *);

    void LoadJvmLib();

protected:
    JavaVM *jvm; 
    
    JNIEnv* GetEnv() {
        std::map<int,JNIEnv*>::const_iterator i
            = threadSpecificEnvs.find(GetThreadId());
        if (i==threadSpecificEnvs.end()) {
            AttachCurrentThread();
        }
        return threadSpecificEnvs[GetThreadId()];
    }
    
    void CreateJVM(const char *classpath);
    
    jobject CreateGlobalRef(jobject obj);
    jclass CreateGlobalRef(jclass obj);
    
    void AttachCurrentThread();
    void DetachCurrentThread();

    int GetThreadId() {
#ifdef __GNUC__
        return syscall(SYS_gettid);
#else
        return 0;
#endif
    }

    JavaVM* GetCreatedJavaVM();
    
public:
    JVM();
    JVM(const char *cp);

    ~JVM();
};

#endif /*JVM_H_*/