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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.events;
import com.google.devtools.build.lib.util.io.OutErr;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Set;
/**
* An event handler that prints to an OutErr stream pair in a
* canonical format, for example:
* <pre>
* ERROR: /home/jrluser/src/workspace/x/BUILD:23:1: syntax error.
* </pre>
* This syntax is parseable by Emacs's compile.el.
*/
public class PrintingEventHandler extends AbstractEventHandler
implements EventHandler {
/**
* A convenient event-handler for terminal applications that prints all
* errors and warnings it encounters to the error stream.
* STDOUT and STDERR events pass their output directly
* through to the corresponding streams.
*/
public static final PrintingEventHandler ERRORS_AND_WARNINGS_TO_STDERR =
new PrintingEventHandler(EventKind.ERRORS_AND_WARNINGS_AND_OUTPUT);
/**
* A convenient event-handler for terminal applications that prints all
* errors it encounters to the error stream.
* STDOUT and STDERR events pass their output directly
* through to the corresponding streams.
*/
public static final PrintingEventHandler ERRORS_TO_STDERR =
new PrintingEventHandler(EventKind.ERRORS_AND_OUTPUT);
private OutErr outErr;
/**
* Setup a printing event handler that prints events matching the mask.
*/
public PrintingEventHandler(OutErr outErr, Set<EventKind> mask) {
super(mask);
this.outErr = outErr;
}
/**
* Setup a printing event handler that prints events matching the mask. Events are printed to the
* System.out and System.err unless/until redirected by a call to setOutErr().
*/
public PrintingEventHandler(Set<EventKind> mask) {
this(OutErr.SYSTEM_OUT_ERR, mask);
}
/**
* Redirect all output to the specified OutErr stream pair.
* Returns the previous OutErr.
*/
public OutErr setOutErr(OutErr outErr) {
OutErr prev = this.outErr;
this.outErr = outErr;
return prev;
}
/**
* Print a description of the specified event to the appropriate
* output or error stream.
*/
@Override
public void handle(Event event) {
if (!getEventMask().contains(event.getKind())) {
handleFollowUpEvents(event);
return;
}
try {
switch (event.getKind()) {
case STDOUT:
outErr.getOutputStream().write(event.getMessageBytes());
outErr.getOutputStream().flush();
break;
case STDERR:
outErr.getErrorStream().write(event.getMessageBytes());
outErr.getErrorStream().flush();
break;
default:
StringBuilder builder = new StringBuilder();
builder.append(event.getKind()).append(": ");
if (event.getLocation() != null) {
builder.append(event.getLocation()).append(": ");
}
builder.append(event.getMessage()).append("\n");
outErr.getErrorStream().write(builder.toString().getBytes(StandardCharsets.UTF_8));
outErr.getErrorStream().flush();
}
} catch (IOException e) {
/*
* Note: we can't print to System.out or System.err here,
* because those will normally be set to streams which
* translate I/O to STDOUT and STDERR events,
* which would result in infinite recursion.
*/
outErr.printErrLn(e.getMessage());
}
handleFollowUpEvents(event);
}
private void handleFollowUpEvents(Event event) {
byte[] stderr = event.getStdErr();
if (stderr != null) {
handle(Event.of(EventKind.STDERR, null, stderr));
}
byte[] stdout = event.getStdOut();
if (stdout != null) {
handle(Event.of(EventKind.STDOUT, null, stdout));
}
}
}