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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
commited5640d8b587fbcfed7dd7967f3de04b37a76f26 (patch)
tree7a5f7c6c9d02226d7471cb3cc8fbbf631b415303 /include/jvmaccess/virtualmachine.hxx
parentInitial commit. (diff)
downloadlibreoffice-ed5640d8b587fbcfed7dd7967f3de04b37a76f26.tar.xz
libreoffice-ed5640d8b587fbcfed7dd7967f3de04b37a76f26.zip
Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_JVMACCESS_VIRTUALMACHINE_HXX
+#define INCLUDED_JVMACCESS_VIRTUALMACHINE_HXX
+
+#include <jvmaccess/jvmaccessdllapi.h>
+#include <rtl/ref.hxx>
+#include <salhelper/simplereferenceobject.hxx>
+
+#if defined __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunknown-attributes"
+#endif
+#include <jni.h>
+#if defined __clang__
+#pragma clang diagnostic pop
+#endif
+
+namespace jvmaccess
+{
+/** An encapsulating wrapper around a Java virtual machine.
+ */
+class JVMACCESS_DLLPUBLIC VirtualMachine final : public salhelper::SimpleReferenceObject
+{
+public:
+ /** A helper to attach a thread to a Java virtual machine.
+
+ @descr
+ Upon construction of a guard the current thread is attached to the
+ virtual machine, and upon destruction of the guard the thread is
+ detached again. For any one thread, multiple instances of this class
+ may be used in a stack-like fashion (care is taken to only really
+ detach the thread from the virtual machine upon destruction of the guard
+ at the bottom of the stack).
+ */
+ class JVMACCESS_DLLPUBLIC AttachGuard
+ {
+ public:
+ /** An exception indicating failure to create an AttachGuard.
+ */
+ class JVMACCESS_DLLPUBLIC CreationException final
+ {
+ public:
+ CreationException();
+
+ CreationException(CreationException const&);
+
+ CreationException& operator=(CreationException const&);
+ };
+
+ /** Attach the current thread to a virtual machine.
+
+ @param rMachine
+ The virtual machine to attach to. Must not be a null reference.
+
+ @exception CreationException
+ Thrown in case attaching fails (due to a JNI problem).
+ */
+ explicit AttachGuard(rtl::Reference<VirtualMachine> xMachine);
+
+ /** Detach the current thread from the virtual machine again.
+ */
+ ~AttachGuard();
+
+ /** Get a JNI environment pointer for the current thread.
+
+ @return
+ A valid JNI environment pointer. Will never be null.
+ */
+ JNIEnv* getEnvironment() const { return m_pEnvironment; }
+
+ private:
+ AttachGuard(AttachGuard const&) = delete;
+ AttachGuard& operator=(AttachGuard const&) = delete;
+
+ rtl::Reference<VirtualMachine> m_xMachine;
+ JNIEnv* m_pEnvironment;
+ bool m_bDetach;
+ };
+
+ /** Create a wrapper around a Java virtual machine.
+
+ @param pVm
+ A JNI pointer to virtual machine. Must not be null.
+
+ @param nVersion
+ The JNI version of the virtual machine pointed to by pVm. Must be at
+ least JNI_VERSION_1_2. This parameter should be of type jint, not int,
+ but at least on some platforms the definition of jint changed from
+ JDK 1.3 (long) to JDK 1.4 (int), so that the mangled C++ name of the
+ constructor would depend on the JDK version used at compile time.
+
+ @param bDestroy
+ Whether to destroy the virtual machine when destructing the wrapper
+ (i.e., whether the wrapper owns the virtual machine pointed to by pVm).
+
+ @param pMainThreadEnv
+ A valid JNI environment pointer for the current thread; must not be
+ null. The current thread must be "initially attached" to the virtual
+ machine while this constructor is being called (i.e., it must be the
+ thread that has called JNI_CreateJavaVM in case the virtual machine has
+ been started via the JNI Invocation API, and it must not already have
+ called DetachCurrentThread; or it must be executing native code called
+ from a "primordial" virtual machine). This environment pointer was
+ formerly used to obtain a reference to the thread's current context
+ class loader (java.lang.Thread.getCurrentClassLoader; if later a native
+ thread was attached to the virtual machine, that thread's context class
+ loader would be null, so the AttachGuard first of all set it to the
+ saved value; this feature has been removed again for performance reasons
+ and because the default context class loader is often not useful, so
+ that code relying on a context class loader has to set one explicitly,
+ anyway). This parameter is currently unused (but may be used again in
+ the future).
+ */
+ VirtualMachine(JavaVM* pVm, int nVersion, bool bDestroy, JNIEnv const* pMainThreadEnv);
+
+private:
+ VirtualMachine(VirtualMachine const&) = delete;
+ VirtualMachine& operator=(VirtualMachine const&) = delete;
+
+ virtual ~VirtualMachine() override;
+
+ JNIEnv* attachThread(bool* pAttached) const;
+
+ void detachThread() const;
+
+ JavaVM* m_pVm;
+ jint m_nVersion;
+ bool m_bDestroy;
+
+ friend class AttachGuard; // to access attachThread, detachThread
+};
+}
+
+#endif // INCLUDED_JVMACCESS_VIRTUALMACHINE_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */