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Merge pull request #321 from ably/feature/ably-instance-store-concurr…
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…ency

`AblyInstanceStore` concurrency
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@QuintinWillison
QuintinWillison committed Feb 8, 2022
2 parents 46c6947 + 1e1c6b9 commit ccc11db
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Showing 2 changed files with 94 additions and 32 deletions.
114 changes: 88 additions & 26 deletions android/src/main/java/io/ably/flutter/plugin/AblyInstanceStore.java
View file
Expand Up @@ -3,6 +3,8 @@
import android.content.Context;
import android.util.LongSparseArray;

import java.util.concurrent.atomic.AtomicLong;

import io.ably.lib.push.Push;
import io.ably.lib.push.PushChannel;
import io.ably.lib.realtime.AblyRealtime;
Expand All @@ -23,9 +25,7 @@
* client by calling @{AblyInstanceStore#getRealtime(final long handle)}.
*/
class AblyInstanceStore {

private static final AblyInstanceStore instance = new AblyInstanceStore();
private long nextHandle = 1;

// Android Studio warns against using HashMap with integer keys, and
// suggests using LongSparseArray. More information at https://stackoverflow.com/a/31413003
Expand All @@ -34,38 +34,100 @@ class AblyInstanceStore {
private final LongSparseArray<AblyRest> restInstances = new LongSparseArray<>();
private final LongSparseArray<AblyRealtime> realtimeInstances = new LongSparseArray<>();
private final LongSparseArray<AsyncPaginatedResult<Object>> paginatedResults = new LongSparseArray<>();
private final AtomicLong nextHandle = new AtomicLong(1);

static synchronized AblyInstanceStore getInstance() {
return instance;
}

/**
* Returns a handle representing the next client that will be created. This handle can be used
* to get the client **after** it is instantiated using [createRest] or [createRealtime].
* A reserved client handle. Safe to be used from any thread.
*
* Instances support the creation of a single Rest or Realtime instance, where only one of the
* create methods may be called and it may only be called once.
*/
long getHandleForNextClient() {
return nextHandle;
interface ClientHandle {
/**
* Get the handle that will be used to store this client when it is created, or the handle
* that was used to store it when it was created.
* This property may be read at any time, from any thread.
*/
long getHandle();

/**
* Create an {@link AblyRest} instance and store it using this handle.
* @param clientOptions The Ably client options for the new Rest instance.
* @param applicationContext The Android application context to supply to the new Rest
* instance using its {@link AblyRest#setAndroidContext(Context)} method.
* @return The handle used to store the instance. Same as {@link #getHandle()}.
* @throws IllegalStateException If this handle has already been used to create a Rest or
* Realtime instance.
* @throws AblyException If the {@link AblyRest} instance creation failed.
*/
long createRest(ClientOptions clientOptions, Context applicationContext) throws AblyException;

/**
* Create an {@link AblyRealtime} instance and store it using this handle.
* @param clientOptions The Ably client options for the new Realtime instance.
* @param applicationContext The Android application context to supply to the new Realtime
* instance using its {@link AblyRealtime#setAndroidContext(Context)} method.
* @return The handle used to store the instance. Same as {@link #getHandle()}.
* @throws IllegalStateException If this handle has already been used to create a Rest or
* Realtime instance.
* @throws AblyException If the {@link AblyRealtime} instance creation failed.
*/
long createRealtime(ClientOptions clientOptions, Context applicationContext) throws AblyException;
}

long createRest(final ClientOptions clientOptions, Context applicationContext) throws AblyException {
final AblyRest rest = new AblyRest(clientOptions);
rest.setAndroidContext(applicationContext);
restInstances.put(nextHandle, rest);
return nextHandle++;
private class ReservedClientHandle implements ClientHandle {
private final long handle;
private volatile boolean used = false;

ReservedClientHandle(final long handle) {
this.handle = handle;
}

@Override
public long getHandle() {
return handle;
}

@Override
public synchronized long createRest(final ClientOptions clientOptions, final Context applicationContext) throws AblyException {
final long handle = use();
final AblyRest rest = new AblyRest(clientOptions);
rest.setAndroidContext(applicationContext);
restInstances.put(handle, rest);
return handle;
}

@Override
public synchronized long createRealtime(final ClientOptions clientOptions, final Context applicationContext) throws AblyException {
final long handle = use();
final AblyRealtime realtime = new AblyRealtime(clientOptions);
realtime.setAndroidContext(applicationContext);
realtimeInstances.put(handle, realtime);
return handle;
}

synchronized long use() {
if (used) {
throw new IllegalStateException("Reserved handle has already been used to create a client instance (handle=" + handle + ").");
}
used = true;
return handle;
}
}

AblyRest getRest(final long handle) {
return restInstances.get(handle);
synchronized ClientHandle reserveClientHandle() {
return new ReservedClientHandle(nextHandle.getAndIncrement());
}

long createRealtime(final ClientOptions clientOptions, Context applicationContext) throws AblyException {
final AblyRealtime realtime = new AblyRealtime(clientOptions);
realtime.setAndroidContext(applicationContext);
realtimeInstances.put(nextHandle, realtime);
return nextHandle++;
synchronized AblyRest getRest(final long handle) {
return restInstances.get(handle);
}

AblyRealtime getRealtime(final long handle) {
synchronized AblyRealtime getRealtime(final long handle) {
return realtimeInstances.get(handle);
}

Expand All @@ -79,38 +141,38 @@ AblyRealtime getRealtime(final long handle) {
* @param handle integer handle to either AblyRealtime or AblyRest
* @return AblyBase
*/
AblyBase getAblyClient(final long handle) {
synchronized AblyBase getAblyClient(final long handle) {
AblyRealtime realtime = getRealtime(handle);
return (realtime != null) ? realtime : getRest(handle);
}

Push getPush(final long handle) {
synchronized Push getPush(final long handle) {
AblyRealtime realtime = getRealtime(handle);
return (realtime != null) ? realtime.push : getRest(handle).push;
}

PushChannel getPushChannel(final long handle, final String channelName) {
synchronized PushChannel getPushChannel(final long handle, final String channelName) {
return getAblyClient(handle)
.channels
.get(channelName).push;
}

long setPaginatedResult(AsyncPaginatedResult result, Integer handle) {
synchronized long setPaginatedResult(AsyncPaginatedResult result, Integer handle) {
long longHandle;
if (handle == null) {
longHandle = nextHandle++;
longHandle = nextHandle.getAndIncrement();
} else {
longHandle = handle.longValue();
}
paginatedResults.put(longHandle, result);
return longHandle;
}

AsyncPaginatedResult<Object> getPaginatedResult(long handle) {
synchronized AsyncPaginatedResult<Object> getPaginatedResult(long handle) {
return paginatedResults.get(handle);
}

void reset() {
synchronized void reset() {
for (int i = 0; i < realtimeInstances.size(); i++) {
long key = realtimeInstances.keyAt(i);
AblyRealtime r = realtimeInstances.get(key);
Expand Down
12 changes: 6 additions & 6 deletions android/src/main/java/io/ably/flutter/plugin/AblyMethodCallHandler.java
View file
Expand Up @@ -183,13 +183,13 @@ private void createRest(@NonNull MethodCall call, @NonNull MethodChannel.Result
final AblyFlutterMessage<PlatformClientOptions> message = (AblyFlutterMessage<PlatformClientOptions>) call.arguments;
this.<PlatformClientOptions>ablyDo(message, (ablyLibrary, clientOptions) -> {
try {
final long handle = ablyLibrary.getHandleForNextClient();
final AblyInstanceStore.ClientHandle clientHandle = ablyLibrary.reserveClientHandle();
if (clientOptions.hasAuthCallback) {
clientOptions.options.authCallback = (Auth.TokenParams params) -> {
final Object[] token = {null};
final CountDownLatch latch = new CountDownLatch(1);
new Handler(Looper.getMainLooper()).post(() -> {
AblyFlutterMessage<Auth.TokenParams> channelMessage = new AblyFlutterMessage<>(params, handle);
AblyFlutterMessage<Auth.TokenParams> channelMessage = new AblyFlutterMessage<>(params, clientHandle.getHandle());
methodChannel.invokeMethod(PlatformConstants.PlatformMethod.authCallback, channelMessage, new MethodChannel.Result() {
@Override
public void success(@Nullable Object result) {
Expand Down Expand Up @@ -220,7 +220,7 @@ public void notImplemented() {
return token[0];
};
}
result.success(ablyLibrary.createRest(clientOptions.options, applicationContext));
result.success(clientHandle.createRest(clientOptions.options, applicationContext));
} catch (final AblyException e) {
handleAblyException(result, e);
}
Expand Down Expand Up @@ -448,13 +448,13 @@ private void createRealtime(@NonNull MethodCall call, @NonNull MethodChannel.Res
final AblyFlutterMessage<PlatformClientOptions> message = (AblyFlutterMessage<PlatformClientOptions>) call.arguments;
this.<PlatformClientOptions>ablyDo(message, (ablyLibrary, clientOptions) -> {
try {
final long handle = ablyLibrary.getHandleForNextClient();
final AblyInstanceStore.ClientHandle clientHandle = ablyLibrary.reserveClientHandle();
if (clientOptions.hasAuthCallback) {
clientOptions.options.authCallback = (Auth.TokenParams params) -> {
final Object[] token = {null};
final CountDownLatch latch = new CountDownLatch(1);
new Handler(Looper.getMainLooper()).post(() -> {
AblyFlutterMessage<Auth.TokenParams> channelMessage = new AblyFlutterMessage<>(params, handle);
AblyFlutterMessage<Auth.TokenParams> channelMessage = new AblyFlutterMessage<>(params, clientHandle.getHandle());
methodChannel.invokeMethod(PlatformConstants.PlatformMethod.realtimeAuthCallback, channelMessage, new MethodChannel.Result() {
@Override
public void success(@Nullable Object result) {
Expand Down Expand Up @@ -487,7 +487,7 @@ public void notImplemented() {
return token[0];
};
}
result.success(ablyLibrary.createRealtime(clientOptions.options, applicationContext));
result.success(clientHandle.createRealtime(clientOptions.options, applicationContext));
} catch (final AblyException e) {
handleAblyException(result, e);
}
Expand Down

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