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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.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.util.LoggingUtil;
import java.util.logging.Level;
import javax.annotation.Nullable;
/**
* 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 {
@Nullable private Location location;
private final String message;
private final boolean dueToIncompleteAST;
private static final Joiner LINE_JOINER = Joiner.on("\n").skipNulls();
private static final Joiner FIELD_JOINER = Joiner.on(": ").skipNulls();
/**
* @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.
this.message = FIELD_JOINER.join(message, getCauseMessage(message));
if (this.message.isEmpty()) {
String details;
if (cause == null) {
details = "Invalid EvalException: no cause given!";
} else {
details = "Invalid EvalException:\n" + Throwables.getStackTraceAsString(cause);
}
LoggingUtil.logToRemote(Level.SEVERE, details, cause);
throw new IllegalArgumentException(details);
}
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 LINE_JOINER.join("\n", FIELD_JOINER.join(getLocation(), message),
(dueToIncompleteAST ? "due to incomplete AST" : ""),
getCauseMessage(message));
}
/**
* @param message the message of this exception, so far.
* @return a message for the cause of the exception, if the main message (passed as argument)
* doesn't already contain this cause; return null if no new information is available.
*/
private String getCauseMessage(String message) {
Throwable cause = getCause();
if (cause == null) {
return null;
}
String causeMessage = cause.getMessage();
if (causeMessage == null) {
return null;
}
if (message == null) {
return causeMessage;
}
// Skip the cause if it is redundant with the message so far.
if (message.contains(causeMessage)) {
return null;
}
return causeMessage;
}
/**
* Returns the error message.
*/
@Override
public String getMessage() {
return message;
}
/**
* Returns the location of the evaluation error.
*/
@Nullable
public Location getLocation() {
return location;
}
/**
* Returns a boolean that tells whether this exception was due to an incomplete AST
*/
public boolean isDueToIncompleteAST() {
return dueToIncompleteAST;
}
/**
* Ensures that this EvalException has proper location information.
* Does nothing if the exception already had a location, or if no location is provided.
* @return this EvalException, in fluent style.
*/
public EvalException ensureLocation(Location loc) {
if (location == null && loc != null) {
location = loc;
}
return this;
}
/**
* Returns whether this exception can be added to a stack trace created by {@link
* EvalExceptionWithStackTrace}.
*/
public boolean canBeAddedToStackTrace() {
return true;
}
/**
* 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);
}
}
}
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