/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.coyote; import java.security.AccessController; import java.security.PrivilegedAction; import org.apache.tomcat.util.net.AbstractEndpoint.Handler.SocketState; import org.apache.tomcat.util.res.StringManager; import org.apache.tomcat.util.security.PrivilegedGetTccl; import org.apache.tomcat.util.security.PrivilegedSetTccl; /** * Manages the state transitions for async requests. * *
* The internal states that are used are: * DISPATCHED - Standard request. Not in Async mode. * STARTING - ServletRequest.startAsync() has been called but the * request in which that call was made has not finished * processing. * STARTED - ServletRequest.startAsync() has been called and the * request in which that call was made has finished * processing. * READ_WRITE_OP - Performing an asynchronous read or write. * MUST_COMPLETE - complete() has been called before the request in which * ServletRequest.startAsync() has finished. As soon as that * request finishes, the complete() will be processed. * COMPLETING - The call to complete() was made once the request was in * the STARTED state. May or may not be triggered by a * container thread - depends if start(Runnable) was used * TIMING_OUT - The async request has timed out and is waiting for a call * to complete(). If that isn't made, the error state will * entered. * MUST_DISPATCH - dispatch() has been called before the request in which * ServletRequest.startAsync() has finished. As soon as that * request finishes, the dispatch() will be processed. * DISPATCHING - The dispatch is being processed. * ERROR - Something went wrong. * * |-----------------»--------------| * | \|/ * | |----------«---------------ERROR---------------------------«-------------------------------| * | | complete() /|\ | \ | * | | | | \---------------| | * | | | | |dispatch() | * | | | |postProcess() \|/ | * | | error()| | | | * | | | | |--|timeout() | | * | | postProcess() | \|/ | \|/ | auto | * | | |---------------»DISPATCHED«---------- | --------------COMPLETING«-----| | * | | | /|\ | | | /|\ | | * | | | |---»-------| | | |--| | | * | | ^ | |startAsync() | timeout() | | * | | | | | | | | * | \|/ | | complete() \|/ postProcess() | | | * | MUST_COMPLETE-«- | ----«------STARTING--»--------- | ------------| ^ | * | /|\ /|\ | | | | complete() | | * | | | | | | | /-----------| | * | | | ^ |dispatch() | | / | * | | | | | | | / | * | | | | \|/ / \|/ / postProcess() | * | | | | MUST_DISPATCH / STARTED«---------«---------| | * | | | | | / / | | | | * | | | | |postProcess() / / | | ^ | * ^ | ^ | | / / | |asyncOperation() | | * | | | | | / / | | | | * | | | | | |---------- / ----------/ | |--READ_WRITE_OP--»---| | * | | | | | | / dispatch() | | | | | * | | | | | | |-----/ auto| | | | error()| * | | | | auto \|/ \|/ \|/ | dispatch()| | |-»--------| * | | | |---«------DISPATCHING«--------«------------- | ------«----| | * | | | /|\ | | * | | | | dispatch() \|/ | * | | | |-----------------------TIMING_OUT | * | | | | | | * | | |-------«----------------------------------«------| | | * | | complete() | | * | | | | * |«- | ----«-------------------«-------------------------------«--| | * | error() | * | complete() | * |----------------------------------------------------------------------------| **/ public class AsyncStateMachine { /** * The string manager for this package. */ private static final StringManager sm = StringManager.getManager(Constants.Package); private static enum AsyncState { DISPATCHED (false, false, false, false, false), STARTING (true, true, false, false, true), STARTED (true, true, false, false, false), MUST_COMPLETE(true, true, true, false, false), COMPLETING (true, false, true, false, false), TIMING_OUT (true, false, false, false, false), MUST_DISPATCH(true, true, false, true, true), DISPATCHING (true, false, false, true, false), READ_WRITE_OP(true, true, false, false, true), ERROR (true, false, false, false, false); private final boolean isAsync; private final boolean isStarted; private final boolean isCompleting; private final boolean isDispatching; private final boolean pauseNonContainerThread; private AsyncState(boolean isAsync, boolean isStarted, boolean isCompleting, boolean isDispatching, boolean pauseNonContainerThread) { this.isAsync = isAsync; this.isStarted = isStarted; this.isCompleting = isCompleting; this.isDispatching = isDispatching; this.pauseNonContainerThread = pauseNonContainerThread; } public boolean isAsync() { return isAsync; } public boolean isStarted() { return isStarted; } public boolean isDispatching() { return isDispatching; } public boolean isCompleting() { return isCompleting; } public boolean getPauseNonContainerThread() { return pauseNonContainerThread; } } private volatile AsyncState state = AsyncState.DISPATCHED; // Need this to fire listener on complete private AsyncContextCallback asyncCtxt = null; private final Processor> processor; public AsyncStateMachine(Processor> processor) { this.processor = processor; } public boolean isAsync() { return state.isAsync(); } public boolean isAsyncDispatching() { return state.isDispatching(); } public boolean isAsyncStarted() { return state.isStarted(); } public boolean isAsyncTimingOut() { return state == AsyncState.TIMING_OUT; } public boolean isAsyncError() { return state == AsyncState.ERROR; } public boolean isCompleting() { return state.isCompleting(); } public synchronized void asyncStart(AsyncContextCallback asyncCtxt) { if (state == AsyncState.DISPATCHED) { state = AsyncState.STARTING; this.asyncCtxt = asyncCtxt; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncStart()", state)); } } public synchronized void asyncOperation() { if (state==AsyncState.STARTED) { state = AsyncState.READ_WRITE_OP; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncOperation()", state)); } } /* * Async has been processed. Whether or not to enter a long poll depends on * current state. For example, as per SRV.2.3.3.3 can now process calls to * complete() or dispatch(). */ public synchronized SocketState asyncPostProcess() { // Unpause any non-container threads that may be waiting for this // container thread to complete this method. Note because of the syncs // those non-container threads won't start back up until until this // method exits. notifyAll(); if (state == AsyncState.STARTING || state == AsyncState.READ_WRITE_OP) { state = AsyncState.STARTED; return SocketState.LONG; } else if (state == AsyncState.MUST_COMPLETE) { asyncCtxt.fireOnComplete(); state = AsyncState.DISPATCHED; return SocketState.ASYNC_END; } else if (state == AsyncState.COMPLETING) { asyncCtxt.fireOnComplete(); state = AsyncState.DISPATCHED; return SocketState.ASYNC_END; } else if (state == AsyncState.MUST_DISPATCH) { state = AsyncState.DISPATCHING; return SocketState.ASYNC_END; } else if (state == AsyncState.DISPATCHING) { state = AsyncState.DISPATCHED; return SocketState.ASYNC_END; } else if (state == AsyncState.STARTED) { // This can occur if an async listener does a dispatch to an async // servlet during onTimeout return SocketState.LONG; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncPostProcess()", state)); } } public synchronized boolean asyncComplete() { pauseNonContainerThread(); boolean doComplete = false; if (state == AsyncState.STARTING) { state = AsyncState.MUST_COMPLETE; } else if (state == AsyncState.STARTED) { state = AsyncState.COMPLETING; doComplete = true; } else if (state == AsyncState.TIMING_OUT || state == AsyncState.ERROR) { state = AsyncState.MUST_COMPLETE; } else if (state == AsyncState.READ_WRITE_OP) { clearNonBlockingListeners(); state = AsyncState.MUST_COMPLETE; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncComplete()", state)); } return doComplete; } public synchronized boolean asyncTimeout() { if (state == AsyncState.STARTED) { state = AsyncState.TIMING_OUT; return true; } else if (state == AsyncState.COMPLETING || state == AsyncState.DISPATCHING || state == AsyncState.DISPATCHED) { // NOOP - App called complete() or dispatch() between the the // timeout firing and execution reaching this point return false; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncTimeout()", state)); } } public synchronized boolean asyncDispatch() { pauseNonContainerThread(); boolean doDispatch = false; if (state == AsyncState.STARTING) { state = AsyncState.MUST_DISPATCH; } else if (state == AsyncState.STARTED) { state = AsyncState.DISPATCHING; // A dispatch is always required. // If on a non-container thread, need to get back onto a container // thread to complete the processing. // If on a container thread the current request/response are not the // request/response associated with the AsyncContext so need a new // container thread to process the different request/response. doDispatch = true; } else if (state == AsyncState.READ_WRITE_OP || state == AsyncState.TIMING_OUT || state == AsyncState.ERROR) { state = AsyncState.DISPATCHING; // If on a container thread then the socket will be added to the // poller poller when the thread exits the // AbstractConnectionHandler.process() method so don't do a dispatch // here which would add it to the poller a second time. if (!ContainerThreadMarker.isContainerThread()) { doDispatch = true; } } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncDispatch()", state)); } return doDispatch; } public synchronized void asyncDispatched() { if (state == AsyncState.DISPATCHING) { state = AsyncState.DISPATCHED; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncDispatched()", state)); } } public synchronized void asyncError() { if (state == AsyncState.DISPATCHED || state == AsyncState.TIMING_OUT || state == AsyncState.READ_WRITE_OP) { clearNonBlockingListeners(); state = AsyncState.ERROR; } else { throw new IllegalStateException( sm.getString("asyncStateMachine.invalidAsyncState", "asyncError()", state)); } } public synchronized void asyncRun(Runnable runnable) { if (state == AsyncState.STARTING || state == AsyncState.STARTED || state == AsyncState.READ_WRITE_OP) { // Execute the runnable using a container thread from the // Connector's thread pool. Use a wrapper to prevent a memory leak ClassLoader oldCL; if (Constants.IS_SECURITY_ENABLED) { PrivilegedAction