svn commit: r1882519 - in /subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native: JNIUtil.cpp JNIUtil.h

[am...@apache.org]

Author: amiloslavskiy
Date: Thu Oct 15 10:13:54 2020
New Revision: 1882519

URL: http://svn.apache.org/viewvc?rev=1882519&view=rev
Log:
JavaHL: Introduce new helper class to temporarily stash Java exceptions

This will be used in subsequent commits. Committed separately to
facilitate code review and cherry-picks.

[in subversion/bindings/javahl]
* native/JNIUtil.cpp
* native/JNIUtil.h
  New class 'StashException', please refer to code comments.

Modified:
    subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.cpp
    subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.h

Modified: subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.cpp
URL: http://svn.apache.org/viewvc/subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.cpp?rev=1882519&r1=1882518&r2=1882519&view=diff
==============================================================================
--- subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.cpp (original)
+++ subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.cpp Thu Oct 15 10:13:54 2020
@@ -1169,3 +1169,28 @@ jthrowable JNIUtil::unwrapJavaException(
     return
         WrappedException::get_exception(err->pool);
 }
+
+StashException::StashException(JNIEnv* env)
+{
+  m_env = env;
+  m_stashed = NULL;
+  stashException();
+}
+
+StashException::~StashException()
+{
+  if (m_stashed)
+    m_env->Throw(m_stashed);
+}
+
+void StashException::stashException()
+{
+  jthrowable jexc = m_env->ExceptionOccurred();
+  if (!jexc)
+    return;
+
+  if (!m_stashed)
+    m_stashed = jexc;
+
+  m_env->ExceptionClear();
+}

Modified: subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.h
URL: http://svn.apache.org/viewvc/subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.h?rev=1882519&r1=1882518&r2=1882519&view=diff
==============================================================================
--- subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.h (original)
+++ subversion/branches/javahl-1.14-fixes/subversion/bindings/javahl/native/JNIUtil.h Thu Oct 15 10:13:54 2020
@@ -330,4 +330,37 @@ class JNIUtil
     }                                                   \
   } while(0)
 
+/**
+ * If there's an exception pending, temporarily stash it away, then
+ * re-throw again in destructor. The goal is to allow some Java calls
+ * to be made despite a pending exception. For example, doing some
+ * necessary cleanup.
+ */
+class StashException
+{
+ public:
+  /*
+   * Works like stashException().
+   */
+   StashException(JNIEnv* env);
+
+  /**
+   * If there's an exception stashed, re-throws it.
+   */
+  ~StashException();
+
+  /**
+   * Check for a pending exception.
+   * If present, stash it away until this class's destructor.
+   * If another exception is already stashed, forget the _new_ one. The
+   * reason behind it is that usually the first exception is the most
+   * informative.
+   */
+  void stashException();
+
+ private:
+   JNIEnv* m_env;
+   jthrowable m_stashed;
+};
+
 #endif  // JNIUTIL_H