npe() runtime intrinsic method.

compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/IntrinsicMethods.java

@@ -87,6 +87,7 @@ public class IntrinsicMethods {
         declareOverload(myStdLib.getLibraryScope().getFunctions("identityEquals"), 1, EQUALS);
         declareOverload(myStdLib.getLibraryScope().getFunctions("plus"), 1, new StringPlus());
         declareOverload(myStdLib.getLibraryScope().getFunctions("Array"), 1, new NewArray());
+        declareOverload(myStdLib.getLibraryScope().getFunctions("npe"), 0, new NPE());
 
         declareIntrinsicFunction("ByteIterator", "next", 0, ITERATOR_NEXT);
         declareIntrinsicFunction("ShortIterator", "next", 0, ITERATOR_NEXT);

compiler/backend/src/org/jetbrains/jet/codegen/intrinsics/NPE.java

@@ -0,0 +1,24 @@
+package org.jetbrains.jet.codegen.intrinsics;
+
+import com.intellij.psi.PsiElement;
+import org.jetbrains.jet.codegen.ExpressionCodegen;
+import org.jetbrains.jet.codegen.JetTypeMapper;
+import org.jetbrains.jet.codegen.StackValue;
+import org.jetbrains.jet.lang.psi.JetExpression;
+import org.objectweb.asm.Type;
+import org.objectweb.asm.commons.InstructionAdapter;
+
+import java.util.List;
+
+/**
+ * @author alex.tkachman
+ */
+public class NPE implements IntrinsicMethod {
+    @Override
+    public StackValue generate(ExpressionCodegen codegen, InstructionAdapter v, Type expectedType, PsiElement element, List<JetExpression> arguments, StackValue receiver) {
+        receiver.put(JetTypeMapper.TYPE_OBJECT, v);
+        v.invokestatic("jet/runtime/Intrinsics", "npe", "(Ljava/lang/Object;)Ljava/lang/Object;");
+        StackValue.onStack(JetTypeMapper.TYPE_OBJECT).put(expectedType, v);
+        return StackValue.onStack(expectedType);
+    }
+}

compiler/frontend/src/jet/Library.jet

@@ -42,9 +42,7 @@ fun Any?.equals(other : Any?) : Boolean// = this === other
 // Returns "null" for null
 fun Any?.toString() : String// = this === other
 
-// fun <T> array(vararg elements : T) : Array<T>
+fun <T : Any> T?.npe() : T
-
-// fun array(vararg elements : Int) : IntArray
 
 fun String?.plus(other: Any?) : String
 

compiler/tests/org/jetbrains/jet/runtime/JetNpeTest.java

@@ -0,0 +1,32 @@
+package org.jetbrains.jet.runtime;
+
+import jet.runtime.Intrinsics;
+import junit.framework.TestCase;
+import org.jetbrains.jet.codegen.CodegenTestCase;
+
+import java.lang.reflect.Method;
+
+public class JetNpeTest extends CodegenTestCase {
+    public void testStackTrace () {
+        try {
+            Intrinsics.npe(null);
+            fail("No NPE thrown");
+        }
+        catch (NullPointerException e) {
+            StackTraceElement stackTraceElement = e.getStackTrace()[0];
+            assertEquals(stackTraceElement.getMethodName(), "testStackTrace");
+            assertEquals(stackTraceElement.getClassName(), "org.jetbrains.jet.runtime.JetNpeTest");
+        }
+    }
+    
+    public void testNotNull () throws Exception {
+        loadText("fun box() = if(10.npe() == 10) \"OK\" else \"fail\"");
+        blackBox();
+    }
+
+    public void testNull () throws Exception {
+        loadText("fun box() = if(null.npe() == 10) \"OK\" else \"fail\"");
+        Method box = generateFunction("box");
+        assertThrows(box, NullPointerException.class, null);
+    }
+}

stdlib/src/jet/runtime/Intrinsics.java

@@ -10,4 +10,14 @@ public class Intrinsics {
     public static String stringPlus(String self, Object other) {
         return ((self == null) ? "null" : self) + ((other == null) ? "null" : other.toString());
     }
+
+    public static Object npe(Object self) {
+        if(self == null)
+            return throwNpe();
+        return self;
+    }
+
+    private static Object throwNpe() {
+        throw new JetNullPointerException();
+    }
 }

stdlib/src/jet/runtime/JetNullPointerException.java

@@ -0,0 +1,32 @@
+package jet.runtime;
+
+import java.util.ArrayList;
+
+/**
+* @author alex.tkachman
+*/
+class JetNullPointerException extends NullPointerException {
+    @Override
+    public synchronized Throwable fillInStackTrace() {
+        super.fillInStackTrace();
+        StackTraceElement[] stackTrace = getStackTrace();
+        ArrayList<StackTraceElement> list = new ArrayList<StackTraceElement>();
+        boolean skip = true;
+        for(StackTraceElement ste : stackTrace) {
+            if(!skip) {
+                list.add(ste);
+            }
+            else {
+                if("jet.runtime.Intrinsics".equals(ste.getClassName()) && "npe".equals(ste.getMethodName())) {
+                    skip = false;
+                }
+            }
+        }
+        setStackTrace(list.toArray(new StackTraceElement[list.size()]));
+        return this;
+    }
+
+    public static void main(String[] args) {
+        Intrinsics.npe(null);
+    }
+}