core/plugins/org.eclipse.dltk.debug/src/org/eclipse/dltk/dbgp/internal/commands/DbgpStackCommands.java

/*******************************************************************************
 * Copyright (c) 2005, 2017 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 *******************************************************************************/
package org.eclipse.dltk.dbgp.internal.commands;

import java.util.Arrays;
import java.util.Comparator;

import org.eclipse.dltk.dbgp.DbgpBaseCommands;
import org.eclipse.dltk.dbgp.DbgpRequest;
import org.eclipse.dltk.dbgp.IDbgpCommunicator;
import org.eclipse.dltk.dbgp.IDbgpStackLevel;
import org.eclipse.dltk.dbgp.commands.IDbgpStackCommands;
import org.eclipse.dltk.dbgp.exceptions.DbgpDebuggingEngineException;
import org.eclipse.dltk.dbgp.exceptions.DbgpException;
import org.eclipse.dltk.dbgp.internal.utils.DbgpXmlEntityParser;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

public class DbgpStackCommands extends DbgpBaseCommands
		implements IDbgpStackCommands {
	private static final String STACK_DEPTH_COMMAND = "stack_depth"; //$NON-NLS-1$

	private static final String STACK_GET_COMMAND = "stack_get"; //$NON-NLS-1$

	private static final String TAG_STACK = "stack"; //$NON-NLS-1$

	private static final String ATTR_DEPTH = "depth"; //$NON-NLS-1$

	protected int parseStackDepthResponse(Element response)
			throws DbgpDebuggingEngineException {
		return Integer.parseInt(response.getAttribute(ATTR_DEPTH));
	}

	protected IDbgpStackLevel[] parseStackLevels(Element response)
			throws DbgpException {
		NodeList nodes = response.getElementsByTagName(TAG_STACK);
		IDbgpStackLevel[] list = new IDbgpStackLevel[nodes.getLength()];
		for (int i = 0; i < nodes.getLength(); ++i) {
			final Element level = (Element) nodes.item(i);
			list[i] = DbgpXmlEntityParser.parseStackLevel(level);
		}
		Arrays.sort(list, STACK_LEVEL_COMPARATOR);
		return list;
	}

	private static final Comparator<IDbgpStackLevel> STACK_LEVEL_COMPARATOR = (
			o1, o2) -> o1.getLevel() - o2.getLevel();

	public DbgpStackCommands(IDbgpCommunicator communicator) {
		super(communicator);
	}

	@Override
	public int getStackDepth() throws DbgpException {
		return parseStackDepthResponse(
				communicate(createRequest(STACK_DEPTH_COMMAND)));
	}

	@Override
	public IDbgpStackLevel getStackLevel(int stackDepth) throws DbgpException {
		DbgpRequest request = createRequest(STACK_GET_COMMAND);
		request.addOption("-d", stackDepth); //$NON-NLS-1$
		IDbgpStackLevel[] levels = parseStackLevels(communicate(request));
		return levels.length == 1 ? levels[0] : null;
	}

	@Override
	public IDbgpStackLevel[] getStackLevels() throws DbgpException {
		return parseStackLevels(communicate(createRequest(STACK_GET_COMMAND)));
	}
}