virtualmachine.cxx

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#include <sal/config.h>
 
#include <cassert>
 
#include <jvmaccess/virtualmachine.hxx>
#include <sal/log.hxx>
#include <utility>
 
using jvmaccess::VirtualMachine;
 
VirtualMachine::AttachGuard::CreationException::CreationException()
{}
 
VirtualMachine::AttachGuard::CreationException::CreationException(
    CreationException const &)
{}
 
VirtualMachine::AttachGuard::CreationException &
VirtualMachine::AttachGuard::CreationException::operator =(
    CreationException const &)
{
    return *this;
}
 
VirtualMachine::AttachGuard::AttachGuard(
    rtl::Reference< VirtualMachine > xMachine):
    m_xMachine(std::move(xMachine))
{
    assert(m_xMachine.is());
    m_pEnvironment = m_xMachine->attachThread(&m_bDetach);
    if (m_pEnvironment == nullptr)
        throw CreationException();
}
 
VirtualMachine::AttachGuard::~AttachGuard()
{
    if (m_bDetach)
        m_xMachine->detachThread();
}
 
VirtualMachine::VirtualMachine(JavaVM * pVm, int nVersion, bool bDestroy,
                               JNIEnv const * pMainThreadEnv):
    m_pVm(pVm), m_nVersion(nVersion), m_bDestroy(bDestroy)
{
    (void) pMainThreadEnv; // avoid warnings
    assert(pVm != nullptr);
    assert(nVersion >= JNI_VERSION_1_2);
    assert(pMainThreadEnv);
}
 
VirtualMachine::~VirtualMachine()
{
    if (m_bDestroy)
    {
        // Do not destroy the VM.  Under Java 1.3, the AWT event loop thread is
        // not a daemon thread and is never terminated, so that calling
        // DestroyJavaVM (waiting for all non-daemon threads to terminate) hangs
        // forever.
/*
        jint n = m_pVm->DestroyJavaVM();
        SAL_WARN_IF(n != JNI_OK, "jvmaccess", "JNI: DestroyJavaVM failed");
*/
    }
}
 
JNIEnv * VirtualMachine::attachThread(bool * pAttached) const
{
    assert(pAttached != nullptr && "bad parameter");
    JNIEnv * pEnv;
    jint n = m_pVm->GetEnv(reinterpret_cast< void ** >(&pEnv), m_nVersion);
    SAL_WARN_IF(
        n != JNI_OK && n != JNI_EDETACHED, "jvmaccess", "JNI: GetEnv failed");
    if (pEnv == nullptr)
    {
        if (m_pVm->AttachCurrentThread
            (
#ifndef ANDROID
             reinterpret_cast< void ** >(&pEnv),
#else
             // The Android <jni.h> has AttachCurrentThread() taking a
             // JNIEnv** and not void **
             &pEnv,
#endif
             nullptr)
            != JNI_OK)
            return nullptr;
        *pAttached = true;
    }
    else
        *pAttached = false;
    return pEnv;
}
 
void VirtualMachine::detachThread() const
{
    jint n = m_pVm->DetachCurrentThread();
    SAL_WARN_IF(n != JNI_OK, "jvmaccess", "JNI: DetachCurrentThread failed");
}
 
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