Filter FB/Java internals for better stack trace for exceptions in user's code.

Author: asfernandes

src/fbjava-tests/src/main/java/example/Functions.java

@@ -19,6 +19,8 @@
 package example;
 
 import java.math.BigDecimal;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
 import java.sql.Blob;
 import java.sql.Connection;
 import java.sql.DriverManager;
@@ -174,4 +176,53 @@ public static String f21(String property)
 	{
 		return System.getProperty(property);
 	}
+
+	public static String f22(String property)
+	{
+		return AccessController.doPrivileged(new PrivilegedAction<String>() {
+			@Override
+			public String run()
+			{
+				return System.getProperty(property);
+			}
+		});
+	}
+
+	public static int f23() throws Exception
+	{
+		throw new Exception("f23");
+	}
+
+	public static int f24() throws Exception
+	{
+		try
+		{
+			f23();
+			return 0;
+		}
+		catch (Exception e)
+		{
+			throw new Exception("f24", e);
+		}
+	}
+
+	public static class C1
+	{
+		public static String s = System.getProperty("x");
+
+		public static int f25()
+		{
+			return 0;
+		}
+	}
+
+	public static class C2
+	{
+		public static String s = System.getProperty("java.version");
+
+		public static int f26()
+		{
+			return 0;
+		}
+	}
 }

src/fbjava/src/main/java/org/firebirdsql/fbjava/impl/CallableThrowable.java

@@ -0,0 +1,31 @@
+/*
+ * FB/Java plugin
+ *
+ * Distributable under LGPL license.
+ * You may obtain a copy of the License at http://www.gnu.org/copyleft/lgpl.html
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * LGPL License for more details.
+ *
+ * This file was created by members of the Firebird development team.
+ * All individual contributions remain the Copyright (C) of those
+ * individuals.  Contributors to this file are either listed here or
+ * can be obtained from a git log command.
+ *
+ * All rights reserved.
+ */
+package org.firebirdsql.fbjava.impl;
+
+
+/***
+ * A Callable which throws Throwable.
+ *
+ * @author asfernandes
+ */
+@FunctionalInterface
+interface CallableThrowable<V>
+{
+	V call() throws Throwable;
+}

src/fbjava/src/main/java/org/firebirdsql/fbjava/impl/ExternalEngine.java

@@ -30,6 +30,7 @@
 import java.net.URLStreamHandler;
 import java.security.AccessControlContext;
 import java.security.Principal;
+import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;
 import java.security.ProtectionDomain;
 import java.sql.Blob;
@@ -40,7 +41,6 @@
 import java.util.Calendar;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -1152,8 +1152,9 @@ private Routine getRoutine(IStatus status, IExternalContext context, IRoutineMet
 			String className = entryPoint.substring(0, methodStart - 1).trim();
 			String methodName = entryPoint.substring(methodStart, paramsStart).trim();
 
-			Class<?> clazz = runInClassLoader(context.getUserName(),
+			Class<?> clazz = runInClassLoader(context.getUserName(), className, methodName,
 				() -> Class.forName(className, true, sharedData.classLoader));
+
 			Routine routine = new Routine(this);
 			ArrayList<Class<?>> paramTypes = new ArrayList<>();
 
@@ -1378,7 +1379,8 @@ private char peekChar(String s, int[] pos) throws FbException
 		return s.charAt(pos[0]);
 	}
 
-	<T> T runInClassLoader(String userName, Callable<T> callable) throws Exception
+	<T> T runInClassLoader(String userName, String className, String methodName, CallableThrowable<T> callable)
+		throws Throwable
 	{
 		ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();
 		try
@@ -1393,13 +1395,71 @@ <T> T runInClassLoader(String userName, Callable<T> callable) throws Exception
 
 			AccessControlContext acc = new AccessControlContext(protectionDomains);
 
-			return Subject.doAsPrivileged(subj, new PrivilegedExceptionAction<T>() {
-				@Override
-				public T run() throws Exception
+			try
+			{
+				return Subject.doAsPrivileged(subj, new PrivilegedExceptionAction<T>() {
+					@Override
+					public T run() throws Exception
+					{
+						try
+						{
+							return callable.call();
+						}
+						catch (Throwable t)
+						{
+							// We cannot pass a Throwable with PrivilegedExceptionAction, so we enclose it with an
+							// Exception. This is the reason we call getClause() two times below.
+							throw new Exception(t);
+						}
+					}
+				}, acc);
+			}
+			catch (PrivilegedActionException privilegedException)
+			{
+				// Lets filter the stack trace to remove garbage from user POV. We start removing the
+				// privilegedException trace, then we remove up to the user class and method name.
+				// From all frames.
+
+				Throwable userException = privilegedException.getCause().getCause();	// explained above
+				StackTraceElement[] privilegedTrace = privilegedException.getStackTrace();
+
+				for (Throwable currentException = userException;
+					 currentException != null;
+					 currentException = currentException.getCause())
 				{
-					return callable.call();
+					StackTraceElement[] currentTrace = currentException.getStackTrace();
+
+					for (int i = currentTrace.length - 1, j = privilegedTrace.length - 1; i >= 0; --i)
+					{
+						if (!currentTrace[i].equals(privilegedTrace[j]))
+							break;
+
+						if (j-- == 0)
+						{
+							int k = i;
+
+							while (--k >= 0 &&
+								!(currentTrace[k].getClassName().equals(className) &&
+								  (currentTrace[k].getMethodName().equals(methodName) ||
+								   "<clinit>".equals(currentTrace[k].getMethodName()))))
+							{
+							}
+
+							if (k < 0 &&
+								!(currentException instanceof ExceptionInInitializerError ||
+								  currentException instanceof NoClassDefFoundError))
+							{
+								k = i - 1;
+							}
+
+							currentException.setStackTrace(Arrays.copyOf(currentTrace, k + 1));
+							break;
+						}
+					}
 				}
-			}, acc);
+
+				throw userException;
+			}
 		}
 		finally
 		{

src/fbjava/src/main/java/org/firebirdsql/fbjava/impl/ExternalProcedure.java

@@ -93,6 +93,8 @@ public IExternalResultSet open(IStatus status, IExternalContext context, Pointer
 				{
 					String userName = context.getUserName();
 
+					//// FIXME: Stack trace filtering is not working fully correct here.
+
 					class ExtResultSet implements IExternalResultSetIntf
 					{
 						private IExternalResultSet wrapper;
@@ -102,10 +104,12 @@ public void dispose()
 						{
 							try
 							{
-								routine.engine.runInClassLoader(userName, () -> {
-									rs.close();
-									return null;
-								});
+								routine.engine.runInClassLoader(userName,
+									routine.method.getDeclaringClass().getName(), routine.method.getName(),
+									() -> {
+										rs.close();
+										return null;
+									});
 							}
 							catch (Throwable t)
 							{
@@ -122,20 +126,22 @@ public boolean fetch(IStatus status) throws FbException
 
 							try
 							{
-								return routine.engine.runInClassLoader(userName, () -> {
-									if (rs.fetch())
-									{
-										for (int i = inCount; i < inOut.length; ++i)
-											inOut2[i] = Array.get(inOut[i], 0);
-
-										routine.putInMessage(status, context, routine.outputParameters,
-											inOut2, inCount, outMsg);
-
-										return true;
-									}
-									else
-										return false;
-								});
+								return routine.engine.runInClassLoader(userName,
+									routine.method.getDeclaringClass().getName(), routine.method.getName(),
+									() -> {
+										if (rs.fetch())
+										{
+											for (int i = inCount; i < inOut.length; ++i)
+												inOut2[i] = Array.get(inOut[i], 0);
+
+											routine.putInMessage(status, context, routine.outputParameters,
+												inOut2, inCount, outMsg);
+
+											return true;
+										}
+										else
+											return false;
+									});
 							}
 							catch (Throwable t)
 							{

src/fbjava/src/main/java/org/firebirdsql/fbjava/impl/FbException.java

@@ -18,6 +18,9 @@
  */
 package org.firebirdsql.fbjava.impl;
 
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
 import org.firebirdsql.fbjava.impl.FbClientLibrary.IStatus;
 import org.firebirdsql.gds.ISCConstants;
 
@@ -38,19 +41,25 @@ public FbException(String msg)
 		super(msg);
 	}
 
-	public static void rethrow(Throwable t) throws FbException
+	public FbException(String msg, Throwable t)
 	{
-		t.printStackTrace(System.out);	//// FIXME:
+		super(msg, t);
+	}
 
-		if (t instanceof FbException)
-			throw (FbException) t;
-		else
-			throw new FbException(t);
+	public static void rethrow(Throwable t) throws FbException
+	{
+		throw new FbException(null, t);
 	}
 
 	public static void catchException(IStatus status, Throwable t)
 	{
-		String msg = t.getMessage();
+		while (t != null && t instanceof FbException && t.getMessage() == null)
+			t = t.getCause();
+
+		StringWriter sw = new StringWriter();
+		PrintWriter pw = new PrintWriter(sw);
+		t.printStackTrace(pw);
+		String msg = sw.toString();
 
 		try (CloseableMemory memory = new CloseableMemory(msg.length() + 1))
 		{

src/fbjava/src/main/java/org/firebirdsql/fbjava/impl/Routine.java

@@ -112,8 +112,18 @@ void putInMessage(IStatus status, IExternalContext context, List<Parameter> para
 		}
 	}
 
-	Object run(IExternalContext context, Object[] args) throws Exception
+	Object run(IExternalContext context, Object[] args) throws Throwable
 	{
-		return engine.runInClassLoader(context.getUserName(), () -> method.invoke(null, args));
+		return engine.runInClassLoader(context.getUserName(), method.getDeclaringClass().getName(), method.getName(),
+			() -> {
+				try
+				{
+					return method.invoke(null, args);
+				}
+				catch (Exception | ExceptionInInitializerError t)
+				{
+					throw t.getCause();
+				}
+			});
 	}
 }