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// Copyright 2014 Google Inc. 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;
import com.google.common.base.Preconditions;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.util.LoggingUtil;
import java.util.logging.Level;
/**
* Exceptions thrown during evaluation of BUILD ASTs or Skylark extensions.
*
* <p>This exception must always correspond to a repeatable, permanent error, i.e. evaluating the
* same package again must yield the same exception. Notably, do not use this for reporting I/O
* errors.
*
* <p>This requirement is in place so that we can cache packages where an error is reported by way
* of {@link EvalException}.
*/
public class EvalException extends Exception {
private final Location location;
private final String message;
private final boolean dueToIncompleteAST;
/**
* @param location the location where evaluation/execution failed.
* @param message the error message.
*/
public EvalException(Location location, String message) {
this.location = location;
this.message = Preconditions.checkNotNull(message);
this.dueToIncompleteAST = false;
}
/**
* @param location the location where evaluation/execution failed.
* @param message the error message.
* @param dueToIncompleteAST if the error is caused by a previous error, such as parsing.
*/
public EvalException(Location location, String message, boolean dueToIncompleteAST) {
this.location = location;
this.message = Preconditions.checkNotNull(message);
this.dueToIncompleteAST = dueToIncompleteAST;
}
/**
* @param location the location where evaluation/execution failed.
* @param message the error message.
* @param cause a Throwable that caused this exception.
*/
public EvalException(Location location, String message, Throwable cause) {
super(cause);
this.location = location;
// This is only used from Skylark, it's useful for debugging. Note that this only happens
// when the Precondition below kills the execution anyway.
if (message == null) {
message = "";
}
if (cause != null) {
message = message + (message.isEmpty() ? "" : ": ") + cause.getMessage();
}
if (message.isEmpty()) {
LoggingUtil.logToRemote(Level.SEVERE, "Invalid EvalException", cause);
throw new IllegalArgumentException("Invalid EvalException");
}
this.message = message;
this.dueToIncompleteAST = false;
}
public EvalException(Location location, Throwable cause) {
this(location, null, cause);
}
/**
* Returns the error message with location info if exists.
*/
public String print() { // TODO(bazel-team): do we also need a toString() method?
return this.getClass().getName()
+ (getLocation() == null ? "" : " at " + getLocation()) + ": "
+ (message == null ? "" : message + "\n")
+ (dueToIncompleteAST ? "due to incomplete AST\n" : "")
+ (getCause() != null && getCause().getMessage() != null ? getCause().getMessage() : "");
}
/**
* Returns the error message.
*/
@Override
public String getMessage() {
return message;
}
/**
* Returns the location of the evaluation error.
*/
public Location getLocation() {
return location;
}
/**
* Returns a boolean that tells whether this exception was due to an incomplete AST
*/
public boolean isDueToIncompleteAST() {
return dueToIncompleteAST;
}
/**
* A class to support a special case of EvalException when the cause of the error is an
* Exception during a direct Java call. Allow the throwing code to provide context in a message.
*/
public static final class EvalExceptionWithJavaCause extends EvalException {
/**
* @param location the location where evaluation/execution failed.
* @param message the error message.
* @param cause a Throwable that caused this exception.
*/
public EvalExceptionWithJavaCause(Location location, String message, Throwable cause) {
super(location, message, cause);
}
/**
* @param location the location where evaluation/execution failed.
* @param cause a Throwable that caused this exception.
*/
public EvalExceptionWithJavaCause(Location location, Throwable cause) {
this(location, null, cause);
}
}
}