1 files changed, 34 insertions, 0 deletions
diff --git a/src/main/java/com/squareup/okhttp/Connection.java b/src/main/java/com/squareup/okhttp/Connection.java
index 73c4b56..cfda281 100644
--- a/src/main/java/com/squareup/okhttp/Connection.java
+++ b/src/main/java/com/squareup/okhttp/Connection.java
@@ -31,6 +31,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.Proxy;
 import java.net.Socket;
+import java.net.SocketTimeoutException;
 import java.net.URL;
 import java.util.Arrays;
 import javax.net.ssl.SSLSocket;
@@ -192,6 +193,39 @@ public final class Connection implements Closeable {
     return !socket.isClosed() && !socket.isInputShutdown() && !socket.isOutputShutdown();
   }
 
+  /**
+   * Returns true if we are confident that we can read data from this
+   * connection. This is more expensive and more accurate than {@link
+   * #isAlive()}; callers should check {@link #isAlive()} first.
+   */
+  public boolean isReadable() {
+    if (!(in instanceof BufferedInputStream)) {
+      return true; // Optimistic.
+    }
+    if (isSpdy()) {
+      return true; // Optimistic. We can't test SPDY because its streams are in use.
+    }
+    BufferedInputStream bufferedInputStream = (BufferedInputStream) in;
+    try {
+      int readTimeout = socket.getSoTimeout();
+      try {
+        socket.setSoTimeout(1);
+        bufferedInputStream.mark(1);
+        if (bufferedInputStream.read() == -1) {
+          return false; // Stream is exhausted; socket is closed.
+        }
+        bufferedInputStream.reset();
+        return true;
+      } finally {
+        socket.setSoTimeout(readTimeout);
+      }
+    } catch (SocketTimeoutException ignored) {
+      return true; // Read timed out; socket is good.
+    } catch (IOException e) {
+      return false; // Couldn't read; socket is closed.
+    }
+  }
+
   public void resetIdleStartTime() {
     if (spdyConnection != null) {
       throw new IllegalStateException("spdyConnection != null");