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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.syntax;
/**
* A class for flow statements (e.g. break and continue)
*/
public final class FlowStatement extends Statement {
public static final FlowStatement BREAK = new FlowStatement("break", true);
public static final FlowStatement CONTINUE = new FlowStatement("continue", false);
private final String name;
private final FlowException ex;
/**
*
* @param name The label of the statement (either break or continue)
* @param terminateLoop Determines whether the enclosing loop should be terminated completely
* (break)
*/
protected FlowStatement(String name, boolean terminateLoop) {
this.name = name;
this.ex = new FlowException(terminateLoop);
}
@Override
void doExec(Environment env) throws EvalException {
throw ex;
}
@Override
void validate(ValidationEnvironment env) throws EvalException {
if (!env.isInsideLoop()) {
throw new EvalException(getLocation(), name + " statement must be inside a for loop");
}
}
@Override
public String toString() {
return name;
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
/**
* An exception that signals changes in the control flow (e.g. break or continue)
*/
class FlowException extends EvalException {
private final boolean terminateLoop;
/**
*
* @param terminateLoop Determines whether the enclosing loop should be terminated completely
* (break)
*/
public FlowException(boolean terminateLoop) {
super(FlowStatement.this.getLocation(), "FlowException with terminateLoop = "
+ terminateLoop);
this.terminateLoop = terminateLoop;
}
/**
* Returns whether the enclosing loop should be terminated completely (break)
*
* @return {@code True} for 'break', {@code false} for 'continue'
*/
public boolean mustTerminateLoop() {
return terminateLoop;
}
@Override
public boolean canBeAddedToStackTrace() {
return false;
}
}
}
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