Instances of this class act on behalf of the call, using one or more streams over one or * more connections. This class has APIs to release each of the above resources: * *
This class supports {@linkplain #cancel asynchronous canceling}. This is intended to have
* the smallest blast radius possible. If an HTTP/2 stream is active, canceling will cancel that
* stream but not the other streams sharing its connection. But if the TLS handshake is still in
* progress then canceling may break the entire connection.
* @hide This class is not part of the Android public SDK API
*/
public final class StreamAllocation {
public final Address address;
private final ConnectionPool connectionPool;
// State guarded by connectionPool.
private RouteSelector routeSelector;
private RealConnection connection;
private boolean released;
private boolean canceled;
private HttpStream stream;
public StreamAllocation(ConnectionPool connectionPool, Address address) {
this.connectionPool = connectionPool;
this.address = address;
}
public HttpStream newStream(int connectTimeout, int readTimeout, int writeTimeout,
boolean connectionRetryEnabled, boolean doExtensiveHealthChecks)
throws RouteException, IOException {
try {
RealConnection resultConnection = findHealthyConnection(connectTimeout, readTimeout,
writeTimeout, connectionRetryEnabled, doExtensiveHealthChecks);
HttpStream resultStream;
if (resultConnection.framedConnection != null) {
resultStream = new Http2xStream(this, resultConnection.framedConnection);
} else {
resultConnection.getSocket().setSoTimeout(readTimeout);
resultConnection.source.timeout().timeout(readTimeout, MILLISECONDS);
resultConnection.sink.timeout().timeout(writeTimeout, MILLISECONDS);
resultStream = new Http1xStream(this, resultConnection.source, resultConnection.sink);
}
synchronized (connectionPool) {
resultConnection.streamCount++;
stream = resultStream;
return resultStream;
}
} catch (IOException e) {
throw new RouteException(e);
}
}
/**
* Finds a connection and returns it if it is healthy. If it is unhealthy the process is repeated
* until a healthy connection is found.
*/
private RealConnection findHealthyConnection(int connectTimeout, int readTimeout,
int writeTimeout, boolean connectionRetryEnabled, boolean doExtensiveHealthChecks)
throws IOException, RouteException {
while (true) {
RealConnection candidate = findConnection(connectTimeout, readTimeout, writeTimeout,
connectionRetryEnabled);
// If this is a brand new connection, we can skip the extensive health checks.
synchronized (connectionPool) {
if (candidate.streamCount == 0) {
return candidate;
}
}
// Otherwise do a potentially-slow check to confirm that the pooled connection is still good.
if (candidate.isHealthy(doExtensiveHealthChecks)) {
return candidate;
}
connectionFailed();
}
}
/**
* Returns a connection to host a new stream. This prefers the existing connection if it exists,
* then the pool, finally building a new connection.
*/
private RealConnection findConnection(int connectTimeout, int readTimeout, int writeTimeout,
boolean connectionRetryEnabled) throws IOException, RouteException {
synchronized (connectionPool) {
if (released) throw new IllegalStateException("released");
if (stream != null) throw new IllegalStateException("stream != null");
if (canceled) throw new IOException("Canceled");
RealConnection allocatedConnection = this.connection;
if (allocatedConnection != null && !allocatedConnection.noNewStreams) {
return allocatedConnection;
}
// Attempt to get a connection from the pool.
RealConnection pooledConnection = Internal.instance.get(connectionPool, address, this);
if (pooledConnection != null) {
this.connection = pooledConnection;
return pooledConnection;
}
// Attempt to create a connection.
if (routeSelector == null) {
routeSelector = new RouteSelector(address, routeDatabase());
}
}
Route route = routeSelector.next();
RealConnection newConnection = new RealConnection(route);
acquire(newConnection);
synchronized (connectionPool) {
Internal.instance.put(connectionPool, newConnection);
this.connection = newConnection;
if (canceled) throw new IOException("Canceled");
}
newConnection.connect(connectTimeout, readTimeout, writeTimeout, address.getConnectionSpecs(),
connectionRetryEnabled);
routeDatabase().connected(newConnection.getRoute());
return newConnection;
}
public void streamFinished(HttpStream stream) {
synchronized (connectionPool) {
if (stream == null || stream != this.stream) {
throw new IllegalStateException("expected " + this.stream + " but was " + stream);
}
}
deallocate(false, false, true);
}
public HttpStream stream() {
synchronized (connectionPool) {
return stream;
}
}
private RouteDatabase routeDatabase() {
return Internal.instance.routeDatabase(connectionPool);
}
public synchronized RealConnection connection() {
return connection;
}
public void release() {
deallocate(false, true, false);
}
/** Forbid new streams from being created on the connection that hosts this allocation. */
public void noNewStreams() {
deallocate(true, false, false);
}
/**
* Releases resources held by this allocation. If sufficient resources are allocated, the
* connection will be detached or closed.
*/
private void deallocate(boolean noNewStreams, boolean released, boolean streamFinished) {
RealConnection connectionToClose = null;
synchronized (connectionPool) {
if (streamFinished) {
this.stream = null;
}
if (released) {
this.released = true;
}
if (connection != null) {
if (noNewStreams) {
connection.noNewStreams = true;
}
if (this.stream == null && (this.released || connection.noNewStreams)) {
release(connection);
if (connection.streamCount > 0) {
routeSelector = null;
}
if (connection.allocations.isEmpty()) {
connection.idleAtNanos = System.nanoTime();
if (Internal.instance.connectionBecameIdle(connectionPool, connection)) {
connectionToClose = connection;
}
}
connection = null;
}
}
}
if (connectionToClose != null) {
Util.closeQuietly(connectionToClose.getSocket());
}
}
public void cancel() {
HttpStream streamToCancel;
RealConnection connectionToCancel;
synchronized (connectionPool) {
canceled = true;
streamToCancel = stream;
connectionToCancel = connection;
}
if (streamToCancel != null) {
streamToCancel.cancel();
} else if (connectionToCancel != null) {
connectionToCancel.cancel();
}
}
private void connectionFailed(IOException e) {
synchronized (connectionPool) {
if (routeSelector != null) {
if (connection.streamCount == 0) {
// Record the failure on a fresh route.
Route failedRoute = connection.getRoute();
routeSelector.connectFailed(failedRoute, e);
} else {
// We saw a failure on a recycled connection, reset this allocation with a fresh route.
routeSelector = null;
}
}
}
connectionFailed();
}
/** Finish the current stream and prevent new streams from being created. */
public void connectionFailed() {
deallocate(true, false, true);
}
/**
* Use this allocation to hold {@code connection}. Each call to this must be paired with a call to
* {@link #release} on the same connection.
*/
public void acquire(RealConnection connection) {
connection.allocations.add(new WeakReference<>(this));
}
/** Remove this allocation from the connection's list of allocations. */
private void release(RealConnection connection) {
for (int i = 0, size = connection.allocations.size(); i < size; i++) {
Reference