content: /*
   * 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 io.airlift.bytecode.control;
  
  import com.google.common.collect.ImmutableList;
  import io.airlift.bytecode.BytecodeBlock;
  import io.airlift.bytecode.BytecodeNode;
  import io.airlift.bytecode.BytecodeVisitor;
  import io.airlift.bytecode.MethodGenerationContext;
  import io.airlift.bytecode.instruction.LabelNode;
  import org.objectweb.asm.MethodVisitor;
  
  import java.util.List;
  
  import static com.google.common.base.Preconditions.checkState;
  
  public class ForLoop
          implements FlowControl
  {
      private final String comment;
      private final BytecodeBlock initialize = new BytecodeBlock();
      private final BytecodeBlock condition = new BytecodeBlock();
      private final BytecodeBlock update = new BytecodeBlock();
      private final BytecodeBlock body = new BytecodeBlock();
  
      private final LabelNode beginLabel = new LabelNode("beginLabel");
      private final LabelNode continueLabel = new LabelNode("continue");
      private final LabelNode endLabel = new LabelNode("end");
  
      public ForLoop()
      {
          this.comment = null;
      }
  
      public ForLoop(String format, Object... args)
      {
          this.comment = String.format(format, args);
      }
  
      @Override
      public String getComment()
      {
          return comment;
      }
  
      public LabelNode getContinueLabel()
      {
          return continueLabel;
      }
  
      public LabelNode getEndLabel()
      {
          return endLabel;
      }
  
      public BytecodeBlock initialize()
      {
          return initialize;
      }
  
      public ForLoop initialize(BytecodeNode node)
      {
          checkState(initialize.isEmpty(), "initialize already set");
          initialize.append(node);
          return this;
      }
  
      public BytecodeBlock condition()
      {
          return condition;
      }
  
      public ForLoop condition(BytecodeNode node)
      {
          checkState(condition.isEmpty(), "condition already set");
          condition.append(node);
          return this;
      }
  
      public BytecodeBlock update()
      {
          return update;
      }
  
      public ForLoop update(BytecodeNode node)
      {
          checkState(update.isEmpty(), "update already set");
          update.append(node);
          return this;
      }
  
      public BytecodeBlock body()
      {
          return body;
      }
  
      public ForLoop body(BytecodeNode node)
      {
          checkState(body.isEmpty(), "body already set");
          body.append(node);
          return this;
      }
  
      @Override
      public void accept(MethodVisitor visitor, MethodGenerationContext generationContext)
      {
          checkState(!condition.isEmpty(), "ForLoop does not have a condition set");
  
          BytecodeBlock block = new BytecodeBlock();
  
          block.append(new BytecodeBlock()
                  .setDescription("initialize")
                  .append(initialize));
  
          block.visitLabel(beginLabel)
                  .append(new BytecodeBlock()
                          .setDescription("condition")
                          .append(condition))
                  .ifFalseGoto(endLabel);
  
          block.append(new BytecodeBlock()
                  .setDescription("body")
                  .append(body));
  
          block.visitLabel(continueLabel)
                  .append(new BytecodeBlock()
                          .setDescription("update")
                          .append(update))
                  .gotoLabel(beginLabel)
                  .visitLabel(endLabel);
  
          block.accept(visitor, generationContext);
      }
  
      @Override
      public List<BytecodeNode> getChildNodes()
      {
          return ImmutableList.of(initialize, condition, update, body);
      }
  
      @Override
      public <T> T accept(BytecodeNode parent, BytecodeVisitor<T> visitor)
      {
          return visitor.visitFor(parent, this);
      }
  }
  