/*
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.flex.compiler.internal.as.codegen;
import org.apache.flex.abc.semantics.Label;
import org.apache.flex.compiler.internal.tree.as.SwitchNode;
/**
* There is an active SwitchControlFlowContext for the syntactic region of each
* switch statement. The SwitchControlFlowContext regions are pushed and popped of the
* activation stack in the {@link ControlFlowContextManager} by the appropriate
* reduction actions. A context is active while the switch statement's subtrees are reduced;
* the SwitchControlFlowContext is set up by calling
* {@link ControlFlowContextManager#startSwitchContext(SwitchNode)} in the
* reduction's Prologue. The SwitchControlFlowContext is torn down by calling
* {@code ControlFlowContextManager#finishSwitchControlFlowContext(InstructionList)}
* in the reduction's "epilogue." ( JBURG does not have a formal epilogue construct
* so for now the "epilogue" is just open coded in each reduction ).
* {@code ControlFlowContextManager#finishSwitchControlFlowContext(InstructionList)}
* is typically one of the last actions in the epilogue, since it may add a
* pending label to the reduction's result InstructionList, and the pending
* label needs to be resolved to the next statement after the statement that set
* up the c-f context.
*
*/
class SwitchControlFlowContext extends ControlFlowContext
{
SwitchControlFlowContext(SwitchNode node)
{
super(node);
}
/**
* break statements branching out of the statement
* that established this control flow context target
* this label.
* @see {@link #getBreakLabel()}, which creates the label.
*/
private Label breakLabel = null;
/**
* @return this control-flow context's break Label, synthesized if necessary.
*/
@Override
Label getBreakLabel()
{
if ( null == this.breakLabel )
this.breakLabel = new Label("#break#" + Integer.toHexString(this.hashCode()));
return this.breakLabel;
}
/**
* @return true if the context's break label has been touched.
*/
boolean hasActiveBreak()
{
return breakLabel != null;
}
@Override
boolean hasDefaultBreakLabel()
{
return true;
}
}