Workaround for Android db locking/closing issue (#193)

README.md

@@ -85,6 +85,20 @@ function onDeviceReady() {
 
 **NOTE:** The database file name should include the extension, if desired.
 
+### Workaround for Android db locking issue
+
+An [issue was reported](https://github.com/brodysoft/Cordova-SQLitePlugin/issues/193), as observed by several people that on some newer versions of the Android, if the app is stopped or aborted without closing the db then:
+- (sometimes) there is an unexpected db lock
+- the data that was inserted before is lost.
+
+It is suspected that this issue is caused by [this Android sqlite commit](https://github.com/android/platform_external_sqlite/commit/d4f30d0d1544f8967ee5763c4a1680cb0553039f), which references and includes the sqlite commit at: http://www.sqlite.org/src/info/6c4c2b7dba
+
+The workaround is enabled by opening the database like:
+
+```js
+  var db = window.sqlitePlugin.openDatabase({name: "my.db", androidLockWorkaround: 1});
+```
+
 ### Pre-populated database
 
 For Android & iOS (*only*): put the database file in the `www` directory and open the database like:

SQLitePlugin.coffee.md

@@ -450,6 +450,9 @@
         if !!openargs.createFromLocation and openargs.createFromLocation == 1
           openargs.createFromResource = "1"
 
+        if !!openargs.androidLockWorkaround and openargs.androidLockWorkaround == 1
+          openargs.androidLockWorkaround = 1
+
         new SQLitePlugin openargs, okcb, errorcb
 
       deleteDb: (first, success, error) ->

src/android/org/pgsqlite/SQLitePlugin.java

@@ -240,12 +240,12 @@ private SQLiteDatabase openDatabase(String dbname, boolean createFromAssets, Cal
 
             SQLiteDatabase mydb = SQLiteDatabase.openOrCreateDatabase(dbfile, null);
 
-            //if (cbc != null) // needed for Android locking/closing workaround
+            if (cbc != null) // needed for Android locking/closing workaround
                 cbc.success();
 
             return mydb;
         } catch (SQLiteException e) {
-            //if (cbc != null) // needed for Android locking/closing workaround
+            if (cbc != null) // needed for Android locking/closing workaround
                 cbc.error("can't open database " + e);
             throw e;
         }
@@ -821,7 +821,7 @@ private void bindPreHoneycomb(JSONObject row, String key, Cursor cursor, int i)
     private class DBRunner implements Runnable {
         final String dbname;
         private boolean createFromAssets;
-        //private boolean androidLockWorkaround;
+        private boolean androidLockWorkaround;
         final BlockingQueue<DBQuery> q;
         final CallbackContext openCbc;
 
@@ -830,7 +830,10 @@ private class DBRunner implements Runnable {
         DBRunner(final String dbname, JSONObject options, CallbackContext cbc) {
             this.dbname = dbname;
             this.createFromAssets = options.has("createFromResource");
-            //this.androidLockWorkaround = options.has("androidLockWorkaround");
+            this.androidLockWorkaround = options.has("androidLockWorkaround");
+            if (this.androidLockWorkaround)
+                Log.v(SQLitePlugin.class.getSimpleName(), "Android db closing/locking workaround applied");
+
             this.q = new LinkedBlockingQueue<DBQuery>();
             this.openCbc = cbc;
         }
@@ -853,12 +856,12 @@ public void run() {
                     executeSqlBatch(dbname, dbq.queries, dbq.jsonparams, dbq.queryIDs, dbq.cbc);
 
                     // XXX workaround for Android locking/closing issue:
-                    //if (androidLockWorkaround && dbq.queries.length == 1 && dbq.queries[0] == "COMMIT") {
-                    //    Log.v(SQLitePlugin.class.getSimpleName(), "close and reopen db");
-                    //    closeDatabaseNow(dbname);
-                    //    this.mydb = openDatabase(dbname, false, null);
-                    //    Log.v(SQLitePlugin.class.getSimpleName(), "close and reopen db finished");
-                    //}
+                    if (androidLockWorkaround && dbq.queries.length == 1 && dbq.queries[0] == "COMMIT") {
+                        // Log.v(SQLitePlugin.class.getSimpleName(), "close and reopen db");
+                        closeDatabaseNow(dbname);
+                        this.mydb = openDatabase(dbname, false, null);
+                        // Log.v(SQLitePlugin.class.getSimpleName(), "close and reopen db finished");
+                    }
 
                     dbq = q.take();
                 }