/*
*
* 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 static org.apache.flex.abc.ABCConstants.OP_popscope;
import static org.apache.flex.abc.ABCConstants.OP_pushwith;
import org.apache.flex.abc.instructionlist.InstructionList;
import org.apache.flex.compiler.tree.as.IASNode;
/**
* The WithContext tracks the usage of a with scope
* in the body of the with statement; if a temp is
* needed to reinitialize the scope stack in a catch
* or finally block, it will be recorded here.
*/
class WithContext extends LabelScopeControlFlowContext
{
/**
* The scope that allocated this with.
* Used to allocate and release the temp.
*/
LexicalScope currentScope;
/**
* The temp allocated to store the with scope.
*/
Binding withStorage = null;
/**
* Construct a with scope.
* @param mgr - the defining ControlFlowContextManager.
*/
WithContext(IASNode withContents, ControlFlowContextManager mgr)
{
super(withContents);
this.currentScope = mgr.currentScope;
}
/**
* Get the temp used to store the with scope,
* allocating it as necessary.
* @return the temp's Binding.
*/
Binding getWithStorage()
{
if ( !hasWithStorage() )
{
this.withStorage = currentScope.allocateTemp();
}
return this.withStorage;
}
/**
* @return true if a temp has been allocated.
*/
boolean hasWithStorage()
{
return this.withStorage != null;
}
/**
* Finish the lifecycle of this with context;
* release the temp as necessary.
*/
void finish(InstructionList result)
{
if ( hasWithStorage() )
currentScope.releaseTemp(this.withStorage);
}
@Override
InstructionList addExitPath(InstructionList exitBranch)
{
InstructionList with_fixup = new InstructionList();
with_fixup.addInstruction(OP_popscope);
with_fixup.addInstruction(getWithStorage().kill());
with_fixup.addAll(exitBranch);
return with_fixup;
}
@Override
void addExceptionHandlerEntry(InstructionList exceptionHandler)
{
// This causes the with context to allocate a temp (if not already allocated),
// which in turn causes the withStmt reduction in the CG to populate that temp.
exceptionHandler.addInstruction(getWithStorage().getlocal());
exceptionHandler.addInstruction(OP_pushwith);
}
}