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/*******************************************************************************
* Copyright (c) 2009, 2021 Mountainminds GmbH & Co. KG and Contributors
* This program and the accompanying materials are made available under
* the terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* Marc R. Hoffmann - initial API and implementation
*
*******************************************************************************/
package org.jacoco.core.internal.flow;
import java.util.ArrayList;
import java.util.List;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.commons.AnalyzerAdapter;
/**
* IFrame implementation which creates snapshots from an {@link AnalyzerAdapter}
*/
class FrameSnapshot implements IFrame {
private static final FrameSnapshot NOP = new FrameSnapshot(null, null);
private final Object[] locals;
private final Object[] stack;
private FrameSnapshot(final Object[] locals, final Object[] stack) {
this.locals = locals;
this.stack = stack;
}
/**
* Create a IFrame instance based on the given analyzer.
*
* @param analyzer
* analyzer instance or <code>null</code>
* @param popCount
* number of items to remove from the operand stack
* @return IFrame instance. In case the analyzer is <code>null</code> or
* does not contain stackmap information a "NOP" IFrame is returned.
*/
static IFrame create(final AnalyzerAdapter analyzer, final int popCount) {
if (analyzer == null || analyzer.locals == null) {
return NOP;
}
final Object[] locals = reduce(analyzer.locals, 0);
final Object[] stack = reduce(analyzer.stack, popCount);
return new FrameSnapshot(locals, stack);
}
/**
* Reduce double word types into a single slot as required
* {@link MethodVisitor#visitFrame(int, int, Object[], int, Object[])}
* method.
*/
private static Object[] reduce(final List<Object> source,
final int popCount) {
final List<Object> copy = new ArrayList<Object>(source);
final int size = source.size() - popCount;
copy.subList(size, source.size()).clear();
for (int i = size; --i >= 0;) {
final Object type = source.get(i);
if (type == Opcodes.LONG || type == Opcodes.DOUBLE) {
copy.remove(i + 1);
}
}
return copy.toArray();
}
// === IFrame implementation ===
public void accept(final MethodVisitor mv) {
if (locals != null) {
mv.visitFrame(Opcodes.F_NEW, locals.length, locals, stack.length,
stack);
}
}
}
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