clean up ExternalKeychainProvider, remove content resolver hack

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/DatabaseUtils.java

@@ -0,0 +1,34 @@
+package org.sufficientlysecure.keychain.util;
+
+
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+
+import timber.log.Timber;
+
+
+public class DatabaseUtils {
+    public static void explainQuery(SQLiteDatabase db, String sql) {
+        Cursor explainCursor = db.rawQuery("EXPLAIN QUERY PLAN " + sql, new String[0]);
+
+        // this is a debugging feature, we can be a little careless
+        explainCursor.moveToFirst();
+
+        StringBuilder line = new StringBuilder();
+        for (int i = 0; i < explainCursor.getColumnCount(); i++) {
+            line.append(explainCursor.getColumnName(i)).append(", ");
+        }
+        Timber.d(line.toString());
+
+        while (!explainCursor.isAfterLast()) {
+            line = new StringBuilder();
+            for (int i = 0; i < explainCursor.getColumnCount(); i++) {
+                line.append(explainCursor.getString(i)).append(", ");
+            }
+            Timber.d(line.toString());
+            explainCursor.moveToNext();
+        }
+
+        explainCursor.close();
+    }
+}