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Cosmetics/code style conformance in newly added Java director excepti…

…on handling
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1 parent baec61c commit fdc1772e38b4d27050bc1d4958f155ec67760fc8 @wsfulton wsfulton committed Nov 2, 2013
Showing with 92 additions and 118 deletions.
  1. +92 −118 Lib/java/director.swg
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@@ -11,7 +11,10 @@
#include <iostream>
#endif
+#include <exception>
+
namespace Swig {
+
/* Java object wrapper */
class JObjectWrapper {
public:
@@ -74,16 +77,16 @@ namespace Swig {
}
/* Java proxy releases ownership of C++ object, C++ object is now
- responsible for destruction (creates NewGlobalRef to pin Java
- proxy) */
+ 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 */
+ } else {
+ /* Java releases ownership of C++ object's lifetime */
if (weak_global_) {
jenv->DeleteWeakGlobalRef((jweak)jthis_);
jthis_ = jenv->NewGlobalRef(jself);
@@ -191,88 +194,101 @@ namespace Swig {
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.
+ // Utility methods and classes for exception handling.
-//%feature("director:except") %{
-// jthrowable $error = jenv->ExceptionOccurred();
-// if ($error) {
-// jenv->ExceptionClear();
-// $directorthrowshandlers
-// throw Swig::DirectorException(jenv, $error);
-// }
-//%}
+ // Helper method to determine if a Java throwable matches a particular Java class type
+ bool ExceptionMatches(JNIEnv *jenv, jthrowable excp, const char *clzname) {
+ jboolean matches = false;
-// Define some utility methods and classes. Cannot use fragments since
-// these may be used by %features and in directorthrows typemaps
+ if (excp && jenv && clzname) {
+ // Exceptions need to be cleared for correct behavior.
+ // The caller of ExceptionMatches should restore pending exceptions if desired -
+ // the caller already has the throwable.
+ jenv->ExceptionClear();
-#include <exception>
+ 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)
-// 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
+ // if (jenv->ExceptionCheck()) {
+ // JavaExceptionMessage jstrmsg(jenv, jenv->ExceptionOccurred());
+ // std::cerr << "Error: ExceptionMatches: class '" <<
+ // clzname << "' : " << jstrmsg.message() << std::endl;
+ // }
+ }
+ return matches;
+ }
+
+ // Simple holder for a Java string during exception handling, allowing access to a c-style string
+ class JavaString {
+ public:
+ JavaString(JNIEnv *jenv, jstring jstr) : jenv_(jenv), jstr_(jstr), cstr_(0) {
+ if (jenv_ && jstr_)
cstr_ = (const char *) jenv_->GetStringUTFChars(jstr_, NULL);
- }
}
+
~JavaString() {
- if (jenv_ && jstr_ && cstr_) {
+ 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 &);
+ JavaString &operator=(const JavaString &);
+
+ JNIEnv *jenv_;
+ jstring jstr_;
+ const char *cstr_;
};
- struct JavaExceptionMessage {
- JavaExceptionMessage(JNIEnv * jenv, jthrowable excp) :
- jstrholder_(jenv,exceptionMsgJstr(jenv,excp)) {
+ // Helper to extract the exception message from a Java throwable
+ class JavaExceptionMessage {
+ public:
+ 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 &);
+ JavaExceptionMessage &operator=(const JavaExceptionMessage &);
// Static method to initialize jstrholder_
- static jstring exceptionMsgJstr(JNIEnv * jenv, jthrowable excp) {
+ 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;");
+ 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 problem accessing exception message string, no msg will be available.
+ jmsg = (jstring)jenv->CallObjectMethod(excp, getThrowableMsgMethodID);
}
}
if (jmsg == NULL && jenv->ExceptionCheck()) {
@@ -281,65 +297,26 @@ namespace Swig {
}
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;
- }
+ JavaString jstrholder_;
+ };
- // Provide the class name to allow reconstruction of the original exception
- struct DirectorException : std::exception {
+ // C++ Exception class for converting from Java exceptions thrown during a director method Java upcall
+ class DirectorException : public std::exception {
+ public:
- // Construct a DirectorException from a java throwable
- DirectorException(JNIEnv* jenv,jthrowable excp) : classname_(0), msg_(0) {
+ // 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);
+ jclass thrwclz = jenv->GetObjectClass(excp);
if (thrwclz) {
- // Get the java.lang.Class class
- clzclz = jenv->GetObjectClass(thrwclz);
+ // Get the Java.lang.Class class
+ jclass clzclz = jenv->GetObjectClass(thrwclz);
if (clzclz) {
- mid_getName = jenv->GetMethodID(clzclz, "getName", "()Ljava/lang/String;");
+ jmethodID mid_getName = 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));
@@ -357,8 +334,8 @@ namespace Swig {
msg_ = copystr(exceptionmsg.message());
}
- // Throw as a wrapped Runtime Error explicitly.
- DirectorException(const char * msg) : classname_(0), msg_(0) {
+ // Throw as a wrapped RuntimeError explicitly.
+ DirectorException(const char *msg) : classname_(0), msg_(0) {
classname_ = copypath("java/lang/RuntimeError");
msg_ = copystr(msg);
}
@@ -368,27 +345,22 @@ namespace Swig {
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() {
+ // If there was a 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() {
+
+ 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) {
+ void raiseJavaException(JNIEnv *jenv) {
if (jenv) {
jenv->ExceptionClear();
jmethodID strCtorID = 0;
-
jclass excpclz = jenv->FindClass(classname());
if (excpclz) {
@@ -406,27 +378,29 @@ namespace Swig {
}
private:
- const char * classname_;
- const char * msg_;
-
- static const char * copypath(const char * srcmsg) {
+ static const char *copypath(const char *srcmsg) {
return copystr(srcmsg, 1);
}
- static const char * copystr(const char * srcmsg, int pathrepl=0) {
- char * target = 0;
+
+ static const char *copystr(const char *srcmsg, int pathrepl=0) {
+ char *target = 0;
if (srcmsg) {
- int msglen = 1+strlen(srcmsg); //+1 for null terminator
+ int msglen = 1 + strlen(srcmsg);
target = new char[msglen];
strncpy(target, srcmsg, msglen);
}
// If pathrepl, replace any '.' with '/'
if (pathrepl) {
- for(char *c=target; *c; ++c) {
- if ('.' == *c) *c = '/';
+ for (char *c=target; *c; ++c) {
+ if ('.' == *c)
+ *c = '/';
}
}
return target;
}
+
+ const char *classname_;
+ const char *msg_;
};
}

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