/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.byteCode.control;
import com.facebook.presto.byteCode.Block;
import com.facebook.presto.byteCode.ByteCodeNode;
import com.facebook.presto.byteCode.ByteCodeNodeFactory;
import com.facebook.presto.byteCode.ByteCodeVisitor;
import com.facebook.presto.byteCode.CompilerContext;
import com.facebook.presto.byteCode.instruction.LabelNode;
import com.google.common.collect.ImmutableList;
import org.objectweb.asm.MethodVisitor;
import java.util.List;
import static com.facebook.presto.byteCode.ByteCodeNodes.buildBlock;
import static com.facebook.presto.byteCode.ExpectedType.BOOLEAN;
import static com.facebook.presto.byteCode.ExpectedType.VOID;
public class DoWhileLoop
implements FlowControl
{
public static DoWhileLoopBuilder doWhileLoopBuilder(CompilerContext context)
{
return new DoWhileLoopBuilder(context);
}
public static class DoWhileLoopBuilder
{
private final CompilerContext context;
private final LabelNode continueLabel = new LabelNode("continue");
private final LabelNode endLabel = new LabelNode("end");
private String comment;
private Block body;
private Block condition;
public DoWhileLoopBuilder(CompilerContext context)
{
this.context = context;
context.pushIterationScope(continueLabel, endLabel);
}
public DoWhileLoopBuilder comment(String format, Object... args)
{
this.comment = String.format(format, args);
return this;
}
public DoWhileLoopBuilder body(ByteCodeNodeFactory body)
{
this.body = buildBlock(context, body, VOID, "body");
return this;
}
public DoWhileLoopBuilder condition(ByteCodeNodeFactory condition)
{
this.condition = buildBlock(context, condition, BOOLEAN, "condition");
return this;
}
public DoWhileLoop build()
{
DoWhileLoop doWhileLoop = new DoWhileLoop(context, comment, body, condition, continueLabel, endLabel);
context.popIterationScope();
return doWhileLoop;
}
}
private final CompilerContext context;
private final String comment;
private final Block body;
private final Block condition;
private final LabelNode beginLabel = new LabelNode("begin");
private final LabelNode continueLabel;
private final LabelNode endLabel;
private DoWhileLoop(CompilerContext context, String comment, Block body, Block condition, LabelNode continueLabel, LabelNode endLabel)
{
this.context = context;
this.comment = comment;
this.body = body;
this.condition = condition;
this.continueLabel = continueLabel;
this.endLabel = endLabel;
}
@Override
public String getComment()
{
return comment;
}
@Override
public void accept(MethodVisitor visitor)
{
Block block = new Block(context)
.visitLabel(beginLabel)
.append(body)
.visitLabel(continueLabel)
.append(condition)
.ifZeroGoto(endLabel)
.gotoLabel(beginLabel)
.visitLabel(endLabel);
block.accept(visitor);
}
@Override
public List<ByteCodeNode> getChildNodes()
{
return ImmutableList.<ByteCodeNode>of(body, condition);
}
@Override
public <T> T accept(ByteCodeNode parent, ByteCodeVisitor<T> visitor)
{
return visitor.visitDoWhile(parent, this);
}
}