/*
* Copyright 2000-2014 JetBrains s.r.o.
*
* 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.intellij.openapi.util;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.progress.SomeQueue;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.util.Consumer;
import com.intellij.util.Function;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* For exactly same refresh requests buffering:
* <p/>
* - refresh requests can be merged into one, but general principle is that each request should be reliably followed by refresh action
* - at the moment only one refresh action is being done
* - if request had been submitted while refresh action was in progress, new refresh action is initiated right after first refresh action finishes
*/
@SomeQueue
public class RequestsMerger {
private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.vcs.RequestsMerger");
private final MyWorker myWorker;
private final Object myLock = new Object();
private MyState myState;
private final Consumer<Runnable> myAlarm;
private final List<Runnable> myWaitingStartListeners = new ArrayList<>();
private final List<Runnable> myWaitingFinishListeners = new ArrayList<>();
public RequestsMerger(final Runnable runnable, final Consumer<Runnable> alarm) {
myAlarm = alarm;
myWorker = new MyWorker(runnable);
myState = MyState.empty;
}
public void request() {
LOG.debug("ext: request");
doAction(MyAction.request);
}
public boolean isEmpty() {
synchronized (myLock) {
return MyState.empty.equals(myState);
}
}
public void waitRefresh(final Runnable runnable) {
LOG.debug("ext: wait refresh");
synchronized (myLock) {
myWaitingStartListeners.add(runnable);
}
request();
}
private class MyWorker implements Runnable {
private volatile boolean myInitialized;
private final Runnable myRunnable;
private MyWorker(Runnable runnable) {
myRunnable = runnable;
}
@Override
public void run() {
LOG.debug("worker: started refresh");
try {
doAction(MyAction.start);
myRunnable.run();
myInitialized = true;
}
finally {
doAction(MyAction.finish);
}
}
public boolean isInitialized() {
return myInitialized;
}
}
private void doAction(final MyAction action) {
LOG.debug("doAction: START " + action.name());
final MyExitAction[] exitActions;
List<Runnable> toBeCalled = null;
synchronized (myLock) {
final MyState oldState = myState;
myState = myState.transition(action);
if (oldState.equals(myState)) return;
exitActions = MyTransitionAction.getExit(oldState, myState);
LOG.debug("doAction: oldState: " + oldState.name() + ", newState: " + myState.name());
if (LOG.isDebugEnabled() && exitActions != null) {
final String debugExitActions = StringUtil.join(exitActions, exitAction -> exitAction.name(), " ");
LOG.debug("exit actions: " + debugExitActions);
}
if (exitActions != null) {
for (MyExitAction exitAction : exitActions) {
if (MyExitAction.markStart.equals(exitAction)) {
myWaitingFinishListeners.addAll(myWaitingStartListeners);
myWaitingStartListeners.clear();
}
else if (MyExitAction.markEnd.equals(exitAction)) {
toBeCalled = new ArrayList<>(myWaitingFinishListeners);
myWaitingFinishListeners.clear();
}
}
}
}
if (exitActions != null) {
for (MyExitAction exitAction : exitActions) {
if (MyExitAction.submitRequestToExecutor.equals(exitAction)) {
myAlarm.consume(myWorker);
//myAlarm.addRequest(myWorker, ourDelay);
//ApplicationManager.getApplication().executeOnPooledThread(myWorker);
}
}
}
if (toBeCalled != null) {
for (Runnable runnable : toBeCalled) {
runnable.run();
}
}
LOG.debug("doAction: END " + action.name());
}
private enum MyState {
empty() {
@Override
@NotNull
public MyState transition(MyAction action) {
if (MyAction.request.equals(action)) {
return MyState.requestSubmitted;
}
logWrongAction(this, action);
return this;
}
},
inProgress() {
@Override
@NotNull
public MyState transition(MyAction action) {
if (MyAction.finish.equals(action)) {
return empty;
}
else if (MyAction.request.equals(action)) {
return MyState.inProgressRequestSubmitted;
}
logWrongAction(this, action);
return this;
}
},
inProgressRequestSubmitted() {
@Override
@NotNull
public MyState transition(MyAction action) {
if (MyAction.finish.equals(action)) {
return MyState.requestSubmitted;
}
if (MyAction.start.equals(action)) {
logWrongAction(this, action);
}
return this;
}
},
requestSubmitted() {
@Override
@NotNull
public MyState transition(MyAction action) {
if (MyAction.start.equals(action)) {
return inProgress;
}
else if (MyAction.finish.equals(action)) {
// to be able to be started by another request
logWrongAction(this, action);
return empty;
}
return this;
}
};
// under lock
@NotNull
public abstract MyState transition(final MyAction action);
private static void logWrongAction(final MyState state, final MyAction action) {
LOG.info("Wrong action: state=" + state.name() + ", action=" + action.name());
}
}
private static class MyTransitionAction {
private static final Map<Couple<MyState>, MyExitAction[]> myMap = new HashMap<>();
static {
add(MyState.empty, MyState.requestSubmitted, MyExitAction.submitRequestToExecutor);
add(MyState.requestSubmitted, MyState.inProgress, MyExitAction.markStart);
add(MyState.inProgress, MyState.empty, MyExitAction.markEnd);
add(MyState.inProgressRequestSubmitted, MyState.requestSubmitted, MyExitAction.submitRequestToExecutor, MyExitAction.markEnd);
//... and not real but to be safe:
add(MyState.inProgressRequestSubmitted, MyState.empty, MyExitAction.markEnd);
add(MyState.inProgress, MyState.requestSubmitted, MyExitAction.markEnd);
}
private static void add(final MyState from, final MyState to, final MyExitAction... action) {
myMap.put(Couple.of(from, to), action);
}
@Nullable
public static MyExitAction[] getExit(final MyState from, final MyState to) {
return myMap.get(Couple.of(from, to));
}
}
private enum MyExitAction {
empty,
submitRequestToExecutor,
markStart,
markEnd
}
private enum MyAction {
request,
start,
finish
}
}