Receive app notifications in SimpleCache, so we save our index file

net/android/java/src/org/chromium/net/SimpleCacheActivityStatusNotifier.java

Index: net/android/java/src/org/chromium/net/SimpleCacheActivityStatusNotifier.java
diff --git a/net/android/java/src/org/chromium/net/SimpleCacheActivityStatusNotifier.java b/net/android/java/src/org/chromium/net/SimpleCacheActivityStatusNotifier.java
new file mode 100644
index 0000000000000000000000000000000000000000..626b335f011e0aa02f7e8c0ac23f610d53c8bd93
--- /dev/null
+++ b/net/android/java/src/org/chromium/net/SimpleCacheActivityStatusNotifier.java
@@ -0,0 +1,48 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.net;
+
+import android.util.Log;
+
+import org.chromium.base.ActivityStatus;
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+import org.chromium.base.NativeClassQualifiedName;
+
+/**
+ * Used by the SimpleIndex in net/disk_cache/simple/ to listens to changes in

[Philippe, 2013/04/22 11:35:48]

Nit: the char limit is 100 in Java.

[felipeg, 2013/04/22 16:14:32]

Done.

+ * the android app state such as the app going to the background or foreground.
+ */
+//  extends BroadcastReceiver

[Philippe, 2013/04/22 11:35:48]

You can remove this line.

[felipeg, 2013/04/22 16:14:32]

Done.

+public class SimpleCacheActivityStatusNotifier
+        implements ActivityStatus.StateListener {
+    @CalledByNative
+    static public SimpleCacheActivityStatusNotifier NewInstance(int nativePtr) {

[Philippe, 2013/04/22 11:35:48]

Nit: s/NewInstance/newInstance

[felipeg, 2013/04/22 16:14:32]

Done.

+      return new SimpleCacheActivityStatusNotifier(nativePtr);

[Philippe, 2013/04/22 11:35:48]

Nit: 4 space indent in Java (here and in a few other places).

[felipeg, 2013/04/22 16:14:32]

Done.

+    }
+
+    public SimpleCacheActivityStatusNotifier(int nativePtr) {

[Philippe, 2013/04/22 11:35:48]

You can make this constructor private since this class is supposed to be
instantiated through the static factory method above.

[Philippe, 2013/04/22 11:59:34]

As we discussed this constructor is called on the IO thread but is accessing
some UI thread-only state.

You can retrieve the Android UI looper by doing Looper.getMainLooper(). See
http://developer.android.com/reference/android/os/Looper.html.

Note that ideally all the methods from this Java object should be directly
called from the UI thread but as we discussed you can hardly inject the UI
message loop into the disk cache (this might need to be confirmed though).

[felipeg, 2013/04/22 16:14:32]

Done.

[felipeg, 2013/04/22 16:14:32]

Done.

+        this.mNativePtr = nativePtr;
+        ActivityStatus.registerStateListener(this);
+    }
+
+    // ActivityStatus.StateListener
+    @Override
+    public void onActivityStateChange(int state) {
+        if (state == ActivityStatus.RESUMED ||
+            state == ActivityStatus.PAUSED ||

[Philippe, 2013/04/22 11:35:48]

You can remove support for the PAUSED and DESTROYED state. See
http://developer.android.com/training/basics/activity-lifecycle/pausing.html.

[felipeg, 2013/04/22 16:14:32]

Done.

+            state == ActivityStatus.STOPPED ||
+            state == ActivityStatus.DESTROYED) {
+          assert mNativePtr != 0;
+          nativeNotifyActivityStatusChanged(mNativePtr, state);

[Philippe, 2013/04/22 11:59:34]

As we discussed this is called on the UI thread while your native object lives
on the IO thread. You need to make sure that |mNativePtr| won't be dereferenced
after its deletion.

To do so you can add a destroy() java method that will be called by the native
side on destruction. This method will do two things:
- mNativePtr = 0
- unregister the observer

Note that this destroy method will have to be called from the UI thread.

[felipeg, 2013/04/22 16:14:32]

Done.

+        }
+    }
+
+    @NativeClassQualifiedName("net::SimpleCacheActivityStatusNotifier")
+    private native void nativeNotifyActivityStatusChanged(int nativePtr, int newActivityStatus);
+
+    // Pointer to native object.
+    private int mNativePtr = 0;

[Philippe, 2013/04/22 11:35:48]

Nit: attributes go first usually in Java. You can also make it 'final' if you
are sure that this pointer never needs to be reset (i.e. if the native side
outlives the Java side).

[felipeg, 2013/04/22 16:14:32]

Done.

+}