diff options
Diffstat (limited to 'src/corelib/kernel/qjnienvironment.cpp')
| -rw-r--r-- | src/corelib/kernel/qjnienvironment.cpp | 477 |
1 files changed, 356 insertions, 121 deletions
diff --git a/src/corelib/kernel/qjnienvironment.cpp b/src/corelib/kernel/qjnienvironment.cpp index ddadc2e114..1e2826e76b 100644 --- a/src/corelib/kernel/qjnienvironment.cpp +++ b/src/corelib/kernel/qjnienvironment.cpp @@ -1,44 +1,7 @@ -/**************************************************************************** -** -** Copyright (C) 2021 The Qt Company Ltd. -** Contact: https://www.qt.io/licensing/ -** -** This file is part of the QtCore module of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:LGPL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** GNU Lesser General Public License Usage -** Alternatively, this file may be used under the terms of the GNU Lesser -** General Public License version 3 as published by the Free Software -** Foundation and appearing in the file LICENSE.LGPL3 included in the -** packaging of this file. Please review the following information to -** ensure the GNU Lesser General Public License version 3 requirements -** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. -** -** GNU General Public License Usage -** Alternatively, this file may be used under the terms of the GNU -** General Public License version 2.0 or (at your option) the GNU General -** Public license version 3 or any later version approved by the KDE Free -** Qt Foundation. The licenses are as published by the Free Software -** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 -** included in the packaging of this file. Please review the following -** information to ensure the GNU General Public License requirements will -** be met: https://www.gnu.org/licenses/gpl-2.0.html and -** https://www.gnu.org/licenses/gpl-3.0.html. -** -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2021 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only #include "qjnienvironment.h" -#include "qjniobject.h" #include "qjnihelpers_p.h" #include <QtCore/QThread> @@ -60,12 +23,12 @@ QT_BEGIN_NAMESPACE Since \c JNIEnv doesn't do much error checking, such as exception checking and clearing, QJniEnvironment allows you to do that easily. + For more information about JNIEnv, see \l {Java: Interface Function Table}. + \note This API has been designed and tested for use with Android. It has not been tested for other platforms. */ -static const char qJniThreadName[] = "QtThread"; - class QJniEnvironmentPrivate { public: @@ -81,104 +44,115 @@ public: } }; -struct QJniLocalRefDeleterPrivate -{ - static void cleanup(jobject obj) - { - if (!obj) - return; - - QJniEnvironment env; - env->DeleteLocalRef(obj); - } -}; - -// To simplify this we only define it for jobjects. -typedef QScopedPointer<_jobject, QJniLocalRefDeleterPrivate> QJniScopedLocalRefPrivate; - - Q_GLOBAL_STATIC(QThreadStorage<QJniEnvironmentPrivateTLS *>, jniEnvTLS) - /*! - \fn QJniEnvironment::QJniEnvironment() - Constructs a new JNI Environment object and attaches the current thread to the Java VM. */ QJniEnvironment::QJniEnvironment() : d(new QJniEnvironmentPrivate{}) { + d->jniEnv = getJniEnv(); +} + +/*! + Returns the JNIEnv pointer for the current thread. + + The current thread will be attached to the Java VM. +*/ +JNIEnv *QJniEnvironment::getJniEnv() +{ + JNIEnv *jniEnv = nullptr; + JavaVM *vm = QtAndroidPrivate::javaVM(); - const jint ret = vm->GetEnv((void**)&d->jniEnv, JNI_VERSION_1_6); - if (ret == JNI_OK) // Already attached - return; + const jint ret = vm->GetEnv((void**)&jniEnv, JNI_VERSION_1_6); if (ret == JNI_EDETACHED) { // We need to (re-)attach - JavaVMAttachArgs args = { JNI_VERSION_1_6, qJniThreadName, nullptr }; - if (vm->AttachCurrentThread(&d->jniEnv, &args) != JNI_OK) - return; - - if (!jniEnvTLS->hasLocalData()) // If we attached the thread we own it. - jniEnvTLS->setLocalData(new QJniEnvironmentPrivateTLS); + const QByteArray threadName = QThread::currentThread()->objectName().toUtf8(); + JavaVMAttachArgs args = { JNI_VERSION_1_6, + threadName.isEmpty() ? "QtThread" : threadName.constData(), + nullptr + }; + if (vm->AttachCurrentThread(&jniEnv, &args) == JNI_OK) { + if (!jniEnvTLS->hasLocalData()) // If we attached the thread we own it. + jniEnvTLS->setLocalData(new QJniEnvironmentPrivateTLS); + } } + return jniEnv; } /*! \fn QJniEnvironment::~QJniEnvironment() Detaches the current thread from the Java VM and destroys the QJniEnvironment object. - This will clear any pending exception by calling exceptionCheckAndClear(). + This will clear any pending exception by calling checkAndClearExceptions(). */ QJniEnvironment::~QJniEnvironment() { - exceptionCheckAndClear(); + checkAndClearExceptions(); } /*! - \fn JNIEnv *QJniEnvironment::operator->() + Returns \c true if this instance holds a valid JNIEnv object. - Provides access to the QJniEnvironment's JNIEnv pointer. + \since 6.2 */ -JNIEnv *QJniEnvironment::operator->() +bool QJniEnvironment::isValid() const { return d->jniEnv; } /*! - \fn QJniEnvironment::operator JNIEnv *() const - - Returns the JNI Environment pointer. + Provides access to the JNI Environment's \c JNIEnv pointer. */ -QJniEnvironment::operator JNIEnv* () const +JNIEnv *QJniEnvironment::operator->() const { return d->jniEnv; } /*! - \fn jclass QJniEnvironment::findClass(const char *className) + Returns the JNI Environment's \c JNIEnv object. +*/ +JNIEnv &QJniEnvironment::operator*() const +{ + return *d->jniEnv; +} +/*! + Returns the JNI Environment's \c JNIEnv pointer. +*/ +JNIEnv *QJniEnvironment::jniEnv() const +{ + return d->jniEnv; +} + +/*! Searches for \a className using all available class loaders. Qt on Android uses a custom class loader to load all the .jar files and it must be used to find any classes that are created by that class loader because these classes are not visible when using the default class loader. - Returns the class pointer or null if is not found. + Returns the class pointer or null if \a className is not found. - A use case for this function is searching for a custom class then calling - its member method. The following code snippet creates an instance of the - class \c CustomClass and then calls the \c printFromJava() method: + A use case for this function is searching for a class to call a JNI method + that takes a \c jclass. This can be useful when doing multiple JNI calls on + the same class object which can a bit faster than using a class name in each + call. Additionally, this call looks for internally cached classes first before + doing a JNI call, and returns such a class if found. The following code snippet + creates an instance of the class \c CustomClass and then calls the + \c printFromJava() method: \code QJniEnvironment env; jclass javaClass = env.findClass("org/qtproject/example/android/CustomClass"); - QJniObject classObject(javaClass); - QJniObject javaMessage = QJniObject::fromString("findClass example"); - classObject.callMethod<void>("printFromJava", - "(Ljava/lang/String;)V", - javaMessage.object<jstring>()); + QJniObject::callStaticMethod<void>(javaClass, "printFromJava", + "(Ljava/lang/String;)V", javaMessage.object<jstring>()); \endcode + + \note This call returns a global reference to the class object from the + internally cached classes. */ jclass QJniEnvironment::findClass(const char *className) { @@ -186,8 +160,156 @@ jclass QJniEnvironment::findClass(const char *className) } /*! - \fn JavaVM *QJniEnvironment::javaVM() + Searches for an instance method of a class \a clazz. The method is specified + by its \a methodName and \a signature. + + Returns the method ID or \c nullptr if the method is not found. + + A usecase for this method is searching for class methods and caching their + IDs, so that they could later be used for calling the methods. + + \since 6.2 +*/ +jmethodID QJniEnvironment::findMethod(jclass clazz, const char *methodName, const char *signature) +{ + if (clazz) { + jmethodID id = d->jniEnv->GetMethodID(clazz, methodName, signature); + if (!checkAndClearExceptions(d->jniEnv)) + return id; + } + + return nullptr; +} + +/*! + \fn template<typename ...Args> jmethodId QJniEnvironment::findMethod(jclass clazz, const char *methodName) + \since 6.4 + + Searches for an instance method of a class \a clazz. The method is specified + by its \a methodName, the signature is deduced from the template parameters. + + Returns the method ID or \c nullptr if the method is not found. +*/ + +/*! + Searches for a static method of a class \a clazz. The method is specified + by its \a methodName and \a signature. + + Returns the method ID or \c nullptr if the method is not found. + + A usecase for this method is searching for class methods and caching their + IDs, so that they could later be used for calling the methods. + + \code + QJniEnvironment env; + jclass javaClass = env.findClass("org/qtproject/example/android/CustomClass"); + jmethodID methodId = env.findStaticMethod(javaClass, + "staticJavaMethod", + "(Ljava/lang/String;)V"); + QJniObject javaMessage = QJniObject::fromString("findStaticMethod example"); + QJniObject::callStaticMethod<void>(javaClass, + methodId, + javaMessage.object<jstring>()); + \endcode + + \since 6.2 +*/ +jmethodID QJniEnvironment::findStaticMethod(jclass clazz, const char *methodName, const char *signature) +{ + if (clazz) { + jmethodID id = d->jniEnv->GetStaticMethodID(clazz, methodName, signature); + if (!checkAndClearExceptions(d->jniEnv)) + return id; + } + + return nullptr; +} + +/*! + \fn template<typename ...Args> jmethodId QJniEnvironment::findStaticMethod(jclass clazz, const char *methodName) + \since 6.4 + + Searches for an instance method of a class \a clazz. The method is specified + by its \a methodName, the signature is deduced from the template parameters. + + Returns the method ID or \c nullptr if the method is not found. + + \code + QJniEnvironment env; + jclass javaClass = env.findClass("org/qtproject/example/android/CustomClass"); + jmethodID methodId = env.findStaticMethod<void, jstring>(javaClass, "staticJavaMethod"); + QJniObject javaMessage = QJniObject::fromString("findStaticMethod example"); + QJniObject::callStaticMethod<void>(javaClass, + methodId, + javaMessage.object<jstring>()); + \endcode +*/ + +/*! + Searches for a member field of a class \a clazz. The field is specified + by its \a fieldName and \a signature. + + Returns the field ID or \c nullptr if the field is not found. + + A usecase for this method is searching for class fields and caching their + IDs, so that they could later be used for getting/setting the fields. + + \since 6.2 +*/ +jfieldID QJniEnvironment::findField(jclass clazz, const char *fieldName, const char *signature) +{ + if (clazz) { + jfieldID id = d->jniEnv->GetFieldID(clazz, fieldName, signature); + if (!checkAndClearExceptions()) + return id; + } + + return nullptr; +} + +/*! + \fn template<typename T> jfieldID QJniEnvironment::findField(jclass clazz, const char *fieldName) + \since 6.4 + + Searches for a member field of a class \a clazz. The field is specified + by its \a fieldName. The signature of the field is deduced from the template parameter. + + Returns the field ID or \c nullptr if the field is not found. +*/ + +/*! + Searches for a static field of a class \a clazz. The field is specified + by its \a fieldName and \a signature. + + Returns the field ID or \c nullptr if the field is not found. + + A usecase for this method is searching for class fields and caching their + IDs, so that they could later be used for getting/setting the fields. + + \since 6.2 +*/ +jfieldID QJniEnvironment::findStaticField(jclass clazz, const char *fieldName, const char *signature) +{ + if (clazz) { + jfieldID id = d->jniEnv->GetStaticFieldID(clazz, fieldName, signature); + if (!checkAndClearExceptions()) + return id; + } + return nullptr; +} + +/*! + \fn template<typename T> jfieldID QJniEnvironment::findStaticField(jclass clazz, const char *fieldName) + \since 6.4 + + Searches for a static field of a class \a clazz. The field is specified + by its \a fieldName. The signature of the field is deduced from the template parameter. + + Returns the field ID or \c nullptr if the field is not found. +*/ + +/*! Returns the Java VM interface for the current process. Although it might be possible to have multiple Java VMs per process, Android allows only one. @@ -198,13 +320,11 @@ JavaVM *QJniEnvironment::javaVM() } /*! - \fn bool QJniEnvironment::registerNativeMethods(const char *className, JNINativeMethod methods[], int size) - Registers the Java methods in the array \a methods of size \a size, each of which can call native C++ functions from class \a className. These methods must be registered before any attempt to call them. - Returns True if the registration is successful, otherwise False. + Returns \c true if the registration is successful, otherwise \c false. Each element in the methods array consists of: \list @@ -214,32 +334,95 @@ JavaVM *QJniEnvironment::javaVM() \endlist \code - JNINativeMethod methods[] {{"callNativeOne", "(I)V", reinterpret_cast<void *>(fromJavaOne)}, - {"callNativeTwo", "(I)V", reinterpret_cast<void *>(fromJavaTwo)}}; + const JNINativeMethod methods[] = + {{"callNativeOne", "(I)V", reinterpret_cast<void *>(fromJavaOne)}, + {"callNativeTwo", "(I)V", reinterpret_cast<void *>(fromJavaTwo)}}; QJniEnvironment env; env.registerNativeMethods("org/qtproject/android/TestJavaClass", methods, 2); \endcode */ -bool QJniEnvironment::registerNativeMethods(const char *className, JNINativeMethod methods[], int size) +bool QJniEnvironment::registerNativeMethods(const char *className, const JNINativeMethod methods[], + int size) { - QJniObject classObject(className); + const jclass clazz = findClass(className); - if (!classObject.isValid()) + if (!clazz) return false; - jclass clazz = d->jniEnv->GetObjectClass(classObject.object()); + return registerNativeMethods(clazz, methods, size); +} + +/*! + \fn bool QJniEnvironment::registerNativeMethods(const char *className, std::initializer_list<JNINativeMethod> methods) + \overload + + Registers the native functions methods in \a methods for the Java class \a className. + Returns \c true if the registration is successful, otherwise \c false. +*/ + +#if QT_DEPRECATED_SINCE(6, 2) +/*! + \overload + \deprecated [6.2] Use the overload with a const JNINativeMethod[] instead. + + Registers the Java methods in the array \a methods of size \a size, each of + which can call native C++ functions from class \a className. These methods + must be registered before any attempt to call them. + + Returns \c true if the registration is successful, otherwise \c false. + + Each element in the methods array consists of: + \list + \li The Java method name + \li Method signature + \li The C++ functions that will be executed + \endlist + + \code + JNINativeMethod methods[] = {{"callNativeOne", "(I)V", reinterpret_cast<void *>(fromJavaOne)}, + {"callNativeTwo", "(I)V", reinterpret_cast<void *>(fromJavaTwo)}}; + QJniEnvironment env; + env.registerNativeMethods("org/qtproject/android/TestJavaClass", methods, 2); + \endcode +*/ +bool QJniEnvironment::registerNativeMethods(const char *className, JNINativeMethod methods[], + int size) +{ + return registerNativeMethods(className, const_cast<const JNINativeMethod*>(methods), size); +} +#endif +/*! + \overload + + This overload uses a previously cached jclass instance \a clazz. + + \code + JNINativeMethod methods[] {{"callNativeOne", "(I)V", reinterpret_cast<void *>(fromJavaOne)}, + {"callNativeTwo", "(I)V", reinterpret_cast<void *>(fromJavaTwo)}}; + QJniEnvironment env; + jclass clazz = env.findClass("org/qtproject/android/TestJavaClass"); + env.registerNativeMethods(clazz, methods, 2); + \endcode +*/ +bool QJniEnvironment::registerNativeMethods(jclass clazz, const JNINativeMethod methods[], + int size) +{ if (d->jniEnv->RegisterNatives(clazz, methods, size) < 0) { - exceptionCheckAndClear(); - d->jniEnv->DeleteLocalRef(clazz); + checkAndClearExceptions(); return false; } - - d->jniEnv->DeleteLocalRef(clazz); - return true; } /*! + \fn bool QJniEnvironment::registerNativeMethods(jclass clazz, std::initializer_list<JNINativeMethod> methods) + \overload + + Registers the native functions methods in \a methods for the Java class \a clazz. + Returns \c true if the registration is successful, otherwise \c false. +*/ + +/*! \enum QJniEnvironment::OutputMode \value Silent The exceptions are cleaned silently @@ -248,7 +431,7 @@ bool QJniEnvironment::registerNativeMethods(const char *className, JNINativeMeth */ /*! - \fn QJniEnvironment::exceptionCheckAndClear(OutputMode outputMode = OutputMode::Verbose) + \fn QJniEnvironment::checkAndClearExceptions(OutputMode outputMode = OutputMode::Verbose) Cleans any pending exceptions either silently or reporting stack backtrace, depending on the \a outputMode. @@ -256,26 +439,65 @@ bool QJniEnvironment::registerNativeMethods(const char *className, JNINativeMeth In contrast to \l QJniObject, which handles exceptions internally, if you make JNI calls directly via \c JNIEnv, you need to clear any potential exceptions after the call using this function. For more information about - \c JNIEnv calls that can throw an exception, see \l {Oracle: JNI Functions}{JNI Functions}. + \c JNIEnv calls that can throw an exception, see \l {Java: JNI Functions}{JNI Functions}. \return \c true when a pending exception was cleared. */ -bool QJniEnvironment::exceptionCheckAndClear(QJniEnvironment::OutputMode outputMode) +bool QJniEnvironment::checkAndClearExceptions(QJniEnvironment::OutputMode outputMode) { - if (Q_UNLIKELY(d->jniEnv->ExceptionCheck())) { - if (outputMode != OutputMode::Silent) - d->jniEnv->ExceptionDescribe(); - d->jniEnv->ExceptionClear(); + return checkAndClearExceptions(d->jniEnv, outputMode); +} - return true; +namespace { + // Any pending exception need to be cleared before calling this + QString exceptionMessage(JNIEnv *env, jthrowable exception) + { + if (!exception) + return {}; + + auto logError = []() { + qWarning() << "QJniEnvironment: a null object returned or an exception occurred while " + "fetching a prior exception message"; + }; + + auto checkAndClear = [env]() { + if (Q_UNLIKELY(env->ExceptionCheck())) { + env->ExceptionClear(); + return true; + } + return false; + }; + + const jclass logClazz = env->FindClass("android/util/Log"); + if (checkAndClear() || !logClazz) { + logError(); + return {}; + } + + const jmethodID methodId = env->GetStaticMethodID(logClazz, "getStackTraceString", + "(Ljava/lang/Throwable;)Ljava/lang/String;"); + if (checkAndClear() || !methodId) { + logError(); + return {}; + } + + jvalue value; + value.l = static_cast<jobject>(exception); + const jobject messageObj = env->CallStaticObjectMethodA(logClazz, methodId, &value); + const jstring jmessage = static_cast<jstring>(messageObj); + if (checkAndClear()) + return {}; + + char const *utfMessage = env->GetStringUTFChars(jmessage, 0); + const QString message = QString::fromUtf8(utfMessage); + + env->ReleaseStringUTFChars(jmessage, utfMessage); + + return message; } - - return false; -} +} // end namespace /*! - \fn QJniEnvironment::exceptionCheckAndClear(JNIEnv *env, OutputMode outputMode = OutputMode::Verbose) - Cleans any pending exceptions for \a env, either silently or reporting stack backtrace, depending on the \a outputMode. This is useful when you already have a \c JNIEnv pointer such as in a native function implementation. @@ -283,16 +505,29 @@ bool QJniEnvironment::exceptionCheckAndClear(QJniEnvironment::OutputMode outputM In contrast to \l QJniObject, which handles exceptions internally, if you make JNI calls directly via \c JNIEnv, you need to clear any potential exceptions after the call using this function. For more information about - \c JNIEnv calls that can throw an exception, see \l {Oracle: JNI Functions}{JNI Functions}. + \c JNIEnv calls that can throw an exception, see \l {Java: JNI Functions}{JNI Functions}. \return \c true when a pending exception was cleared. */ -bool QJniEnvironment::exceptionCheckAndClear(JNIEnv *env, QJniEnvironment::OutputMode outputMode) +bool QJniEnvironment::checkAndClearExceptions(JNIEnv *env, QJniEnvironment::OutputMode outputMode) { if (Q_UNLIKELY(env->ExceptionCheck())) { - if (outputMode != OutputMode::Silent) - env->ExceptionDescribe(); - env->ExceptionClear(); + if (outputMode == OutputMode::Verbose) { + if (jthrowable exception = env->ExceptionOccurred()) { + env->ExceptionClear(); + const QString message = exceptionMessage(env, exception); + // Print to QWARN since env->ExceptionDescribe() does the same + if (!message.isEmpty()) + qWarning().noquote() << message; + env->DeleteLocalRef(exception); + } else { + // if the exception object is null for some reason just + env->ExceptionDescribe(); + env->ExceptionClear(); + } + } else { + env->ExceptionClear(); + } return true; } |