// 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.io.PrintWriter; import java.util.Set; /** * An event handler that prints to an OutErr stream pair in a * canonical format, for example: *
 * ERROR: /home/jrluser/src/workspace/x/BUILD:23:1: syntax error.
 * 
* This syntax is parseable by Emacs's compile.el. * *

* By default, the output will go to SYSTEM_OUT_ERR, * but this can be changed by calling the setOut() method. * *

* This class is used only for tests. */ 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 = OutErr.SYSTEM_OUT_ERR; /** * Setup a printing event handler that will handle events matching the mask. * Events will be printed to the original System.out and System.err * unless/until redirected by a call to setOutErr(). */ public PrintingEventHandler(Set mask) { super(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())) { 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: PrintWriter err = new PrintWriter(outErr.getErrorStream()); err.print(event.getKind()); err.print(": "); if (event.getLocation() != null) { err.print(event.getLocation().print()); err.print(": "); } err.println(event.getMessage()); err.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()); } } }