swig/Lib/java/director.swg

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Text

/* -----------------------------------------------------------------------------
* director.swg
*
* This file contains support for director classes that proxy
* method calls from C++ to Java extensions.
* ----------------------------------------------------------------------------- */
#ifdef __cplusplus
#if defined(DEBUG_DIRECTOR_OWNED)
#include <iostream>
#endif
namespace Swig {
/* Java object wrapper */
class JObjectWrapper {
public:
JObjectWrapper() : jthis_(NULL), weak_global_(true) {
}
~JObjectWrapper() {
jthis_ = NULL;
weak_global_ = true;
}
bool set(JNIEnv *jenv, jobject jobj, bool mem_own, bool weak_global) {
if (!jthis_) {
weak_global_ = weak_global || !mem_own; // hold as weak global if explicitly requested or not owned
if (jobj)
jthis_ = weak_global_ ? jenv->NewWeakGlobalRef(jobj) : jenv->NewGlobalRef(jobj);
#if defined(DEBUG_DIRECTOR_OWNED)
std::cout << "JObjectWrapper::set(" << jobj << ", " << (weak_global ? "weak_global" : "global_ref") << ") -> " << jthis_ << std::endl;
#endif
return true;
} else {
#if defined(DEBUG_DIRECTOR_OWNED)
std::cout << "JObjectWrapper::set(" << jobj << ", " << (weak_global ? "weak_global" : "global_ref") << ") -> already set" << std::endl;
#endif
return false;
}
}
jobject get(JNIEnv *jenv) const {
#if defined(DEBUG_DIRECTOR_OWNED)
std::cout << "JObjectWrapper::get(";
if (jthis_)
std::cout << jthis_;
else
std::cout << "null";
std::cout << ") -> return new local ref" << std::endl;
#endif
return (jthis_ ? jenv->NewLocalRef(jthis_) : jthis_);
}
void release(JNIEnv *jenv) {
#if defined(DEBUG_DIRECTOR_OWNED)
std::cout << "JObjectWrapper::release(" << jthis_ << "): " << (weak_global_ ? "weak global ref" : "global ref") << std::endl;
#endif
if (jthis_) {
if (weak_global_) {
if (jenv->IsSameObject(jthis_, NULL) == JNI_FALSE)
jenv->DeleteWeakGlobalRef((jweak)jthis_);
} else
jenv->DeleteGlobalRef(jthis_);
}
jthis_ = NULL;
weak_global_ = true;
}
/* Only call peek if you know what you are doing wrt to weak/global references */
jobject peek() {
return jthis_;
}
/* Java proxy releases ownership of C++ object, C++ object is now
responsible for destruction (creates NewGlobalRef to pin Java
proxy) */
void java_change_ownership(JNIEnv *jenv, jobject jself, bool take_or_release) {
if (take_or_release) { /* Java takes ownership of C++ object's lifetime. */
if (!weak_global_) {
jenv->DeleteGlobalRef(jthis_);
jthis_ = jenv->NewWeakGlobalRef(jself);
weak_global_ = true;
}
} else { /* Java releases ownership of C++ object's lifetime */
if (weak_global_) {
jenv->DeleteWeakGlobalRef((jweak)jthis_);
jthis_ = jenv->NewGlobalRef(jself);
weak_global_ = false;
}
}
}
private:
/* pointer to Java object */
jobject jthis_;
/* Local or global reference flag */
bool weak_global_;
};
/* director base class */
class Director {
/* pointer to Java virtual machine */
JavaVM *swig_jvm_;
protected:
#if defined (_MSC_VER) && (_MSC_VER<1300)
class JNIEnvWrapper;
friend class JNIEnvWrapper;
#endif
/* Utility class for managing the JNI environment */
class JNIEnvWrapper {
const Director *director_;
JNIEnv *jenv_;
int env_status;
public:
JNIEnvWrapper(const Director *director) : director_(director), jenv_(0), env_status(0) {
#if defined(__ANDROID__)
JNIEnv **jenv = &jenv_;
#else
void **jenv = (void **)&jenv_;
#endif
env_status = director_->swig_jvm_->GetEnv((void **)&jenv_, JNI_VERSION_1_2);
#if defined(SWIG_JAVA_ATTACH_CURRENT_THREAD_AS_DAEMON)
// Attach a daemon thread to the JVM. Useful when the JVM should not wait for
// the thread to exit upon shutdown. Only for jdk-1.4 and later.
director_->swig_jvm_->AttachCurrentThreadAsDaemon(jenv, NULL);
#else
director_->swig_jvm_->AttachCurrentThread(jenv, NULL);
#endif
}
~JNIEnvWrapper() {
#if !defined(SWIG_JAVA_NO_DETACH_CURRENT_THREAD)
// Some JVMs, eg jdk-1.4.2 and lower on Solaris have a bug and crash with the DetachCurrentThread call.
// However, without this call, the JVM hangs on exit when the thread was not created by the JVM and creates a memory leak.
if (env_status == JNI_EDETACHED)
director_->swig_jvm_->DetachCurrentThread();
#endif
}
JNIEnv *getJNIEnv() const {
return jenv_;
}
};
/* Java object wrapper */
JObjectWrapper swig_self_;
/* Disconnect director from Java object */
void swig_disconnect_director_self(const char *disconn_method) {
JNIEnvWrapper jnienv(this) ;
JNIEnv *jenv = jnienv.getJNIEnv() ;
jobject jobj = swig_self_.get(jenv);
#if defined(DEBUG_DIRECTOR_OWNED)
std::cout << "Swig::Director::disconnect_director_self(" << jobj << ")" << std::endl;
#endif
if (jobj && jenv->IsSameObject(jobj, NULL) == JNI_FALSE) {
jmethodID disconn_meth = jenv->GetMethodID(jenv->GetObjectClass(jobj), disconn_method, "()V");
if (disconn_meth) {
#if defined(DEBUG_DIRECTOR_OWNED)
std::cout << "Swig::Director::disconnect_director_self upcall to " << disconn_method << std::endl;
#endif
jenv->CallVoidMethod(jobj, disconn_meth);
}
}
jenv->DeleteLocalRef(jobj);
}
public:
Director(JNIEnv *jenv) : swig_jvm_((JavaVM *) NULL), swig_self_() {
/* Acquire the Java VM pointer */
jenv->GetJavaVM(&swig_jvm_);
}
virtual ~Director() {
JNIEnvWrapper jnienv(this) ;
JNIEnv *jenv = jnienv.getJNIEnv() ;
swig_self_.release(jenv);
}
bool swig_set_self(JNIEnv *jenv, jobject jself, bool mem_own, bool weak_global) {
return swig_self_.set(jenv, jself, mem_own, weak_global);
}
jobject swig_get_self(JNIEnv *jenv) const {
return swig_self_.get(jenv);
}
// Change C++ object's ownership, relative to Java
void swig_java_change_ownership(JNIEnv *jenv, jobject jself, bool take_or_release) {
swig_self_.java_change_ownership(jenv, jself, take_or_release);
}
};
}
// Default exception handler for all director methods.
// Can override this for specific methods
// This just documents the default. It is not actually attached as a feature
// for efficiency reasons (and is defined in java.cxx) It can be overridden
// as a feature for specific methods or globally.
//%feature("director:except") %{
// jthrowable $error = jenv->ExceptionOccurred();
// if ($error) {
// jenv->ExceptionClear();
// $directorthrowshandlers
// throw Swig::DirectorException(jenv, $error);
// }
//%}
// Define some utility methods and classes. Cannot use fragments since
// these may be used by %features and in directorthrows typemaps
#include <exception>
// Simple holder for exception messages, allowing access to a c-style string
namespace Swig {
struct JavaString {
JavaString(JNIEnv * jenv, jstring jstr):jenv_(jenv), jstr_(jstr), cstr_(0) {
if (jenv_ && jstr_) {
// Get the null-terminated c-string out, and hold it
cstr_ = (const char *) jenv_->GetStringUTFChars(jstr_, NULL);
}
}
~JavaString() {
if (jenv_ && jstr_ && cstr_) {
jenv_->ReleaseStringUTFChars(jstr_, cstr_);
}
}
const char *cstr() {
return cstr_ ? cstr_ : "";
}
private:
JNIEnv * jenv_;
jstring jstr_;
const char * cstr_;
// non-copyable
JavaString(const JavaString &);
JavaString & operator=(const JavaString &);
};
struct JavaExceptionMessage {
JavaExceptionMessage(JNIEnv * jenv, jthrowable excp) :
jstrholder_(jenv,exceptionMsgJstr(jenv,excp)) {
}
~JavaExceptionMessage() {
}
const char *message() {
return jstrholder_.cstr();
}
private:
JavaString jstrholder_;
// non-copyable
JavaExceptionMessage(const JavaExceptionMessage &);
JavaExceptionMessage & operator=(const JavaExceptionMessage &);
// Static method to initialize jstrholder_
static jstring exceptionMsgJstr(JNIEnv * jenv, jthrowable excp) {
jstring jmsg = NULL;
if (jenv && excp) {
jenv->ExceptionClear(); // Cannot invoke methods with pending exception
jclass thrwclz = jenv->GetObjectClass(excp);
if (thrwclz) {
// if no getMessage() or other exception, no msg available.
jmethodID getThrowableMsgMethodID =
jenv->GetMethodID(thrwclz, "getMessage", "()Ljava/lang/String;");
if (getThrowableMsgMethodID && !jenv->ExceptionCheck()) {
// if problem accessing exception message string, no msg available.
jmsg = (jstring)
jenv->CallObjectMethod(excp, getThrowableMsgMethodID);
}
}
if (jmsg == NULL && jenv->ExceptionCheck()) {
jenv->ExceptionClear();
}
}
return jmsg;
}
};
////////////////////////////////////
bool ExceptionMatches(JNIEnv * jenv, jthrowable excp,
const char *clzname) {
jboolean matches = false;
if (excp && jenv && clzname) {
// Have to clear exceptions for correct behavior. Code around
// ExceptionMatches should restore pending exception if
// desired - already have throwable.
jenv->ExceptionClear();
jclass clz = jenv->FindClass(clzname);
if (clz && ! jenv->ExceptionCheck()) {
jclass classclz = jenv->GetObjectClass(clz);
jmethodID isInstanceMethodID =
jenv->GetMethodID(classclz, "isInstance", "(Ljava/lang/Object;)Z");
if (isInstanceMethodID) {
matches = (jboolean)
jenv->CallBooleanMethod(clz, isInstanceMethodID, excp);
}
}
// This may happen if user typemaps or director:except
// features call ExceptionMatches incorrectly, typically with
// an invalid clzname argument. Uncommenting the debug lines
// may help to diagnose.
// As is, this leaves the underlying case as a pending exception
// which may not be that clear (e.g. ClassNotFoundException)
// if (jenv->ExceptionCheck()) {
// JavaExceptionMessage jstrmsg(jenv,jenv->ExceptionOccurred());
// std::cerr << "Error: ExceptionMatches: class '" <<
// clzname << "' : " << jstrmsg.message() << std::endl;
// }
}
return matches;
}
// Provide the class name to allow reconstruction of the original exception
struct DirectorException : std::exception {
// Construct a DirectorException from a java throwable
DirectorException(JNIEnv* jenv,jthrowable excp) : classname_(0), msg_(0) {
jstring jstr_classname = NULL;
jmethodID mid_getName = NULL;
jclass thrwclz;
jclass clzclz;
if (excp) {
// Get the exception class, like Exception
thrwclz = jenv->GetObjectClass(excp);
if (thrwclz) {
// Get the java.lang.Class class
clzclz = jenv->GetObjectClass(thrwclz);
if (clzclz) {
mid_getName = jenv->GetMethodID(clzclz, "getName", "()Ljava/lang/String;");
if (mid_getName) {
// Get the excp class name
jstr_classname = (jstring)(jenv->CallObjectMethod(thrwclz, mid_getName));
}
}
}
}
// Copy strings, since no guarantee jenv will be active when handled
// If classname_ is 0, returned as "UnknownException"
if (jstr_classname) {
JavaString classname(jenv, jstr_classname);
classname_ = copypath(classname.cstr());
}
JavaExceptionMessage exceptionmsg(jenv, excp);
msg_ = copystr(exceptionmsg.message());
}
// Throw as a wrapped Runtime Error explicitly.
DirectorException(const char * msg) : classname_(0), msg_(0) {
classname_ = copypath("java/lang/RuntimeError");
msg_ = copystr(msg);
}
~DirectorException() throw() {
delete[] classname_;
delete[] msg_;
}
// If there was problem finding classname, keep track of error
// On raiseJavaException will be mapped to a RuntimeException
const char* classname() const throw() {
return classname_ ? classname_ : "UnknownException";
}
const char* what() const throw() {
return msg_ ? msg_ : "";
}
// Python director code provides static raise() methods
// Omitted here: Seems less good than
// throw DirectorException(jenv, excp)
// from which compiler can infer a C++ exception is thrown.
// Reconstruct and raise the Java Exception that caused the DirectorException
void raiseJavaException(JNIEnv* jenv) {
if (jenv) {
jenv->ExceptionClear();
jmethodID strCtorID = 0;
jclass excpclz = jenv->FindClass(classname());
if (excpclz) {
strCtorID = jenv->GetMethodID(excpclz,"<init>","(Ljava/lang/String;)V");
}
if (strCtorID) {
// If exception has a string constructor, throw an instance
jenv->ThrowNew(excpclz, what());
} else {
// Else, throw a runtime
SWIG_JavaThrowException(jenv, SWIG_JavaRuntimeException, what() );
}
}
}
private:
const char * classname_;
const char * msg_;
static const char * copypath(const char * srcmsg) {
return copystr(srcmsg, 1);
}
static const char * copystr(const char * srcmsg, int pathrepl=0) {
char * target = 0;
if (srcmsg) {
int msglen = 1+strlen(srcmsg); //+1 for null terminator
target = new char[msglen];
strncpy(target, srcmsg, msglen);
}
// If pathrepl, replace any '.' with '/'
if (pathrepl) {
for(char *c=target; *c; ++c) {
if ('.' == *c) *c = '/';
}
}
return target;
}
};
}
#endif /* __cplusplus */