Optimize FdEventsReader to make it safer to use.

am: df4c156e6e

Change-Id: I9ee8853bb601fc0b23155e9d758299b446ef413b

1 files changed, 13 insertions, 19 deletions

diff --git a/src/android/net/util/FdEventsReader.java b/src/android/net/util/FdEventsReader.java
index 1380ea7..e82c69b 100644
--- a/src/android/net/util/FdEventsReader.java
+++ b/src/android/net/util/FdEventsReader.java
@@ -63,7 +63,6 @@ import java.io.IOException;
  * the Handler constructor argument is associated.
  *
  * @param <BufferType> the type of the buffer used to read data.
- * @hide
  */
 public abstract class FdEventsReader<BufferType> {
     private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
@@ -93,27 +92,21 @@ public abstract class FdEventsReader<BufferType> {
     }
 
     /** Start this FdEventsReader. */
-    public void start() {
-        if (onCorrectThread()) {
-            createAndRegisterFd();
-        } else {
-            mHandler.post(() -> {
-                logError("start() called from off-thread", null);
-                createAndRegisterFd();
-            });
+    public boolean start() {
+        if (!onCorrectThread()) {
+            throw new IllegalStateException("start() called from off-thread");
         }
+
+        return createAndRegisterFd();
     }
 
     /** Stop this FdEventsReader and destroy the file descriptor. */
     public void stop() {
-        if (onCorrectThread()) {
-            unregisterAndDestroyFd();
-        } else {
-            mHandler.post(() -> {
-                logError("stop() called from off-thread", null);
-                unregisterAndDestroyFd();
-            });
+        if (!onCorrectThread()) {
+            throw new IllegalStateException("stop() called from off-thread");
         }
+
+        unregisterAndDestroyFd();
     }
 
     @NonNull
@@ -178,8 +171,8 @@ public abstract class FdEventsReader<BufferType> {
      */
     protected void onStop() {}
 
-    private void createAndRegisterFd() {
-        if (mFd != null) return;
+    private boolean createAndRegisterFd() {
+        if (mFd != null) return true;
 
         try {
             mFd = createFd();
@@ -189,7 +182,7 @@ public abstract class FdEventsReader<BufferType> {
             mFd = null;
         }
 
-        if (mFd == null) return;
+        if (mFd == null) return false;
 
         mQueue.addOnFileDescriptorEventListener(
                 mFd,
@@ -205,6 +198,7 @@ public abstract class FdEventsReader<BufferType> {
                     return FD_EVENTS;
                 });
         onStart();
+        return true;
     }
 
     private boolean isRunning() {