From bfcb2193b3d64a0a2087d66eadf1e20f37e3addd Mon Sep 17 00:00:00 2001
From: Evan JIANG <firstfan@gmail.com>
Date: Tue, 28 Oct 2008 01:13:38 +0800
Subject: [PATCH] Fix a FileObserver jni bug. The path string in FileObserver
 jni will not be automatically released in the while loop. Then it will cause
 too many local refs in the ref table. When received too many file changed
 notifications/events, the process will be killed for "Failed adding to JNI
 local ref table". Test code:
 ============================================================= import
 android.app.Activity; import android.os.Bundle; import
 android.os.FileObserver; import android.util.Log;

import java.io.File;
import java.io.IOException;

public class TestApp extends Activity {

    public static final String TAG="TestApp";
    FileObserver observer;

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);

        observer=new FileObserver("/tmp"){
            @Override
            public void onEvent(int event, String path) {
                if(event == FileObserver.CREATE){
                    Log.e(TAG, "File created [" + path + "]");
                }else if(event == FileObserver.DELETE){
                    Log.e(TAG, "File deleted [" + path + "]");
                }
            }
        };
        observer.startWatching();

        File f=new File("/tmp/a.txt");
        for (int i=0;i<300;i++) {
            try {
                f.createNewFile();
            } catch (IOException e) {
            }
            f.delete();
        }
    }

}
================================================
The last 2 lines of the log:
E/dalvikvm(  705): Failed adding to JNI local ref table (has 512
entries)
E/dalvikvm(  705): VM aborting
---
 core/jni/android_util_FileObserver.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/core/jni/android_util_FileObserver.cpp b/core/jni/android_util_FileObserver.cpp
index 794478a317de..13a1645557bd 100644
--- a/core/jni/android_util_FileObserver.cpp
+++ b/core/jni/android_util_FileObserver.cpp
@@ -84,6 +84,10 @@ static void android_os_fileobserver_observe(JNIEnv* env, jobject object, jint fd
             }
             
 		    env->CallVoidMethod(object, method_onEvent, event->wd, event->mask, path);
+            if (path != NULL)
+            {
+                env->DeleteLocalRef(path);
+            }
 		    
 		    event_size = sizeof(*event) + event->len;
 			num_bytes -= event_size;
-- 
2.11.0