| // 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)); |
| } |
| } |
| } |