| /******************************************************************************* |
| * Copyright (c) 2000, 2020 IBM Corporation and others. |
| * |
| * This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License 2.0 |
| * which accompanies this distribution, and is available at |
| * https://www.eclipse.org/legal/epl-2.0/ |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdt.internal.debug.eval.ast.engine; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Stack; |
| |
| import org.eclipse.core.runtime.CoreException; |
| import org.eclipse.core.runtime.IStatus; |
| import org.eclipse.core.runtime.Status; |
| import org.eclipse.debug.core.model.IVariable; |
| import org.eclipse.jdt.debug.core.IJavaObject; |
| import org.eclipse.jdt.debug.core.IJavaType; |
| import org.eclipse.jdt.debug.core.IJavaValue; |
| import org.eclipse.jdt.debug.core.IJavaVariable; |
| import org.eclipse.jdt.debug.core.JDIDebugModel; |
| import org.eclipse.jdt.internal.debug.core.JDIDebugPlugin; |
| import org.eclipse.jdt.internal.debug.eval.ast.instructions.Instruction; |
| import org.eclipse.jdt.internal.debug.eval.ast.instructions.InstructionSequence; |
| |
| import com.sun.jdi.VMDisconnectedException; |
| |
| public class Interpreter { |
| private Instruction[] fInstructions; |
| private int fInstructionCounter; |
| private IRuntimeContext fContext; |
| private Stack<Object> fStack; |
| private IJavaValue fLastValue; |
| |
| /** |
| * The list of internal variables |
| */ |
| private Map<String, IVariable> fInternalVariables; |
| |
| /** |
| * List of objects for which GC has been disabled |
| */ |
| private List<IJavaObject> fPermStorage = null; |
| |
| private boolean fStopped = false; |
| |
| public Interpreter(InstructionSequence instructions, IRuntimeContext context) { |
| fInstructions = instructions.getInstructions(); |
| fContext = context; |
| fInternalVariables = new HashMap<>(); |
| } |
| |
| public void execute() throws CoreException { |
| try { |
| reset(); |
| while (fInstructionCounter < fInstructions.length && !fStopped) { |
| Instruction instruction = fInstructions[fInstructionCounter++]; |
| instruction.setInterpreter(this); |
| instruction.execute(); |
| instruction.setInterpreter(null); |
| } |
| } catch (CoreException e) { |
| throw e; |
| } catch (Exception e) { |
| throw new CoreException(new Status(IStatus.ERROR, |
| JDIDebugModel.getPluginIdentifier(), e.getMessage(), e)); |
| } finally { |
| releaseObjects(); |
| } |
| } |
| |
| public void stop() { |
| fStopped = true; |
| } |
| |
| private void reset() { |
| fStack = new Stack<>(); |
| fInstructionCounter = 0; |
| } |
| |
| /** |
| * Jumps to a given address |
| */ |
| public void jump(int offset) { |
| fInstructionCounter += offset; |
| } |
| |
| /** |
| * Pushes an object onto the stack. Disables garbage collection for any |
| * interim object pushed onto the stack. Objects are released after the |
| * evaluation completes. |
| */ |
| public void push(Object object) { |
| fStack.push(object); |
| if (object instanceof IJavaObject) { |
| disableCollection((IJavaObject) object); |
| } |
| } |
| |
| /** |
| * Avoid garbage collecting interim results. |
| * |
| * @param value |
| * object to disable garbage collection for |
| */ |
| private void disableCollection(IJavaObject value) { |
| if (fPermStorage == null) { |
| fPermStorage = new ArrayList<>(5); |
| } |
| try { |
| value.disableCollection(); |
| fPermStorage.add(value); |
| } catch (CoreException e) { |
| // don't worry about GC if the VM has terminated |
| if ((e.getStatus().getException() instanceof VMDisconnectedException)) { |
| return; |
| } |
| JDIDebugPlugin.log(e); |
| } |
| } |
| |
| /** |
| * Re-enable garbage collection if interim results. |
| */ |
| private void releaseObjects() { |
| if (fPermStorage != null) { |
| Iterator<IJavaObject> iterator = fPermStorage.iterator(); |
| while (iterator.hasNext()) { |
| IJavaObject object = iterator.next(); |
| try { |
| object.enableCollection(); |
| } catch (CoreException e) { |
| // don't worry about GC if the VM has terminated |
| if ((e.getStatus().getException() instanceof VMDisconnectedException)) { |
| break; |
| } |
| JDIDebugPlugin.log(e); |
| } |
| } |
| fPermStorage = null; |
| } |
| } |
| |
| /** |
| * Peeks at the top object of the stack |
| */ |
| public Object peek() { |
| return fStack.peek(); |
| } |
| |
| /** |
| * Pops an object off of the stack |
| */ |
| public Object pop() { |
| return fStack.pop(); |
| } |
| |
| /** |
| * Answers the context for the interpreter |
| */ |
| public IRuntimeContext getContext() { |
| return fContext; |
| } |
| |
| public IJavaValue getResult() { |
| if (fStack == null || fStack.isEmpty()) { |
| if (fLastValue == null) { |
| return getContext().getVM().voidValue(); |
| } |
| return fLastValue; |
| } |
| Object top = fStack.peek(); |
| if (top instanceof IJavaVariable) { |
| try { |
| return (IJavaValue) ((IJavaVariable) top).getValue(); |
| } catch (CoreException exception) { |
| return getContext().getVM().newValue( |
| exception.getStatus().getMessage()); |
| } |
| } |
| if (top instanceof IJavaValue) { |
| return (IJavaValue) top; |
| } |
| // XXX: exception |
| return null; |
| } |
| |
| public void setLastValue(IJavaValue value) { |
| fLastValue = value; |
| } |
| |
| /** |
| * Create a new variable in the interpreter with the given name and the |
| * given type. |
| * |
| * @param name |
| * the name of the variable to create. |
| * @param type |
| * the type of the variable to create. |
| * @return the created variable. |
| */ |
| public IVariable createInternalVariable(String name, IJavaType referencType) { |
| IVariable var = new InterpreterVariable(name, referencType, |
| fContext.getVM()); |
| fInternalVariables.put(name, var); |
| return var; |
| } |
| |
| /** |
| * Return the variable with the given name. This method only looks in the |
| * list of internal variable (i.e. created by |
| * Interpreter#createInternalVariable(String, IJavaType)) |
| * |
| * @param name |
| * the name of the variable to retrieve. |
| * @return the corresponding variable, or <code>null</code> if there is |
| * none. |
| */ |
| public IVariable getInternalVariable(String name) { |
| return fInternalVariables.get(name); |
| } |
| } |