GC support for playcounts

src/ch/blinkenlights/android/vanilla/PlayCountsHelper.java

@@ -18,6 +18,7 @@
 package ch.blinkenlights.android.vanilla;
 
 import android.content.Context;
+import android.content.ContentResolver;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.database.Cursor;
@@ -42,9 +43,11 @@ public class PlayCountsHelper extends SQLiteOpenHelper {
 	private static final String INDEX_TYPE_CREATE = "CREATE INDEX idx_type ON "+TABLE_PLAYCOUNTS
 	  + " (type);";
 
+	private Context ctx;
 
 	public PlayCountsHelper(Context context) {
 		super(context, DATABASE_NAME, null, DATABASE_VERSION);
+		ctx = context;
 	}
 
 	@Override
@@ -68,6 +71,7 @@ public class PlayCountsHelper extends SQLiteOpenHelper {
 		SQLiteDatabase dbh = this.getWritableDatabase();
 		dbh.execSQL("INSERT OR IGNORE INTO "+TABLE_PLAYCOUNTS+" (type, type_id, playcount) VALUES ("+MediaUtils.TYPE_SONG+", "+id+", 0);"); // Creates row if not exists
 		dbh.execSQL("UPDATE "+TABLE_PLAYCOUNTS+" SET playcount=playcount+1 WHERE type="+MediaUtils.TYPE_SONG+" AND type_id="+id+";");
+		performGC(dbh, MediaUtils.TYPE_SONG);
 		dbh.close();
 	}
 
@@ -77,14 +81,45 @@ public class PlayCountsHelper extends SQLiteOpenHelper {
 	public ArrayList<Long> getTopSongs() {
 		ArrayList<Long> payload = new ArrayList<Long>();
 		SQLiteDatabase dbh = this.getReadableDatabase();
-		Cursor c = dbh.rawQuery("SELECT type_id FROM "+TABLE_PLAYCOUNTS+" WHERE type="+MediaUtils.TYPE_SONG+" ORDER BY playcount DESC limit 4096", null);
+		Cursor cursor = dbh.rawQuery("SELECT type_id FROM "+TABLE_PLAYCOUNTS+" WHERE type="+MediaUtils.TYPE_SONG+" ORDER BY playcount DESC limit 4096", null);
 
-		while (c.moveToNext()) {
+		while (cursor.moveToNext()) {
-			payload.add(c.getLong(0));
+			payload.add(cursor.getLong(0));
 		}
 
-		c.close();
+		cursor.close();
 		return payload;
 	}
 
+	/**
+	 * Picks a random amount of 'type' items from the provided DBH
+	 * and checks them against Androids media database.
+	 * Items not found in the media library are removed from the DBH's database
+	 */
+	private int performGC(SQLiteDatabase dbh, int type) {
+		ArrayList<Long> toCheck = new ArrayList<Long>(); // List of songs we are going to check
+		QueryTask query;                                 // Reused query object
+		Cursor cursor;                                   // recycled cursor
+		int removed = 0;                                 // Amount of removed items
+
+		// We are just grabbing a bunch of random IDs
+		cursor = dbh.rawQuery("SELECT type_id FROM "+TABLE_PLAYCOUNTS+" WHERE type="+type+" ORDER BY RANDOM() LIMIT 10", null);
+		while (cursor.moveToNext()) {
+			toCheck.add(cursor.getLong(0));
+		}
+		cursor.close();
+
+		for (Long id : toCheck) {
+			query = MediaUtils.buildQuery(type, id, null, null);
+			cursor = query.runQuery(ctx.getContentResolver());
+			if(cursor.getCount() == 0) {
+				dbh.execSQL("DELETE FROM "+TABLE_PLAYCOUNTS+" WHERE type="+type+" AND type_id="+id);
+				removed++;
+			}
+			cursor.close();
+		}
+		Log.v("VanillaMusic", "performGC: items removed="+removed);
+		return removed;
+	}
+
 }