| // 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.skyframe; |
| |
| import com.google.common.base.Preconditions; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * A work queue -- takes {@link Runnable}s and runs them when requested. |
| */ |
| interface Scheduler { |
| /** |
| * Schedules a new action to be eventually done. |
| */ |
| void schedule(Runnable action); |
| |
| /** |
| * Runs the actions that have been scheduled. These actions can in turn schedule new actions, |
| * which will be run as well. |
| * |
| * @throw SchedulerException wrapping a scheduled action's exception. |
| */ |
| void run() throws SchedulerException; |
| |
| /** |
| * Wrapper exception that {@link Runnable}s can throw, to be caught and handled |
| * by callers of {@link #run}. |
| */ |
| static class SchedulerException extends RuntimeException { |
| private final SkyKey failedValue; |
| private final ErrorInfo errorInfo; |
| |
| private SchedulerException(@Nullable Throwable cause, @Nullable ErrorInfo errorInfo, |
| SkyKey failedValue) { |
| super(errorInfo != null ? errorInfo.getException() : cause); |
| this.errorInfo = errorInfo; |
| this.failedValue = Preconditions.checkNotNull(failedValue, errorInfo); |
| } |
| |
| /** |
| * Returns a SchedulerException wrapping an expected error, e.g. an error describing an expected |
| * build failure when trying to evaluate the given value, that should cause Skyframe to produce |
| * useful error information to the user. |
| */ |
| static SchedulerException ofError(ErrorInfo errorInfo, SkyKey failedValue) { |
| Preconditions.checkNotNull(errorInfo); |
| return new SchedulerException(errorInfo.getException(), errorInfo, failedValue); |
| } |
| |
| /** |
| * Returns a SchedulerException wrapping an InterruptedException, e.g. if the user interrupts |
| * the build, that should cause Skyframe to exit as soon as possible. |
| */ |
| static SchedulerException ofInterruption(InterruptedException cause, SkyKey failedValue) { |
| return new SchedulerException(cause, null, failedValue); |
| } |
| |
| SkyKey getFailedValue() { |
| return failedValue; |
| } |
| |
| @Nullable ErrorInfo getErrorInfo() { |
| return errorInfo; |
| } |
| } |
| } |