Move state file code to PlaybackService and add a version code to state file

src/org/kreed/vanilla/PlaybackService.java

@@ -22,6 +22,9 @@
 
 package org.kreed.vanilla;
 
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.EOFException;
 import java.io.IOException;
 import java.util.ArrayList;
 
@@ -50,6 +53,20 @@ import android.util.Log;
 import android.widget.Toast;
 
 public final class PlaybackService extends Service implements Handler.Callback, MediaPlayer.OnCompletionListener, MediaPlayer.OnErrorListener, SharedPreferences.OnSharedPreferenceChangeListener, SongTimeline.Callback {
+	/**
+	 * Name of the state file.
+	 */
+	private static final String STATE_FILE = "state";
+	/**
+	 * Header for state file to help indicate if the file is in the right
+	 * format.
+	 */
+	private static final long STATE_FILE_MAGIC = 0x1533574DC74B6ECL;
+	/**
+	 * State file version that indicates data order.
+	 */
+	private static final int STATE_VERSION = 1;
+
 	private static final int NOTIFICATION_ID = 2;
 
 	/**
@@ -186,7 +203,7 @@ public final class PlaybackService extends Service implements Handler.Callback,
 
 		mTimeline = new SongTimeline(this);
 		mTimeline.setCallback(this);
-		mPendingSeek = mTimeline.loadState();
+		int state = loadState();
 
 		mMediaPlayer = new MediaPlayer();
 		mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
@@ -218,14 +235,6 @@ public final class PlaybackService extends Service implements Handler.Callback,
 
 		initWidgets();
 
-		int state = 0;
-		int finishAction = mTimeline.getFinishAction();
-		if (finishAction == SongTimeline.FINISH_RANDOM)
-			state |= FLAG_RANDOM;
-		else if (finishAction == SongTimeline.FINISH_REPEAT)
-			state |= FLAG_REPEAT;
-		if (mTimeline.isShuffling())
-			state |= FLAG_SHUFFLE;
 		updateState(state);
 		setCurrentSong(0);
 
@@ -285,7 +294,7 @@ public final class PlaybackService extends Service implements Handler.Callback,
 		stopForeground(true);
 
 		if (mMediaPlayer != null) {
-			mTimeline.saveState(mMediaPlayer.getCurrentPosition());
+			saveState(mMediaPlayer.getCurrentPosition());
 			mMediaPlayer.release();
 			mMediaPlayer = null;
 		}
@@ -826,7 +835,7 @@ public final class PlaybackService extends Service implements Handler.Callback,
 		case SAVE_STATE:
 			// For unexpected terminations: crashes, task killers, etc.
 			// In most cases onDestroy will handle this
-			mTimeline.saveState(0);
+			saveState(0);
 			break;
 		case PROCESS_SONG:
 			processSong((Song)message.obj);
@@ -1135,4 +1144,60 @@ public final class PlaybackService extends Service implements Handler.Callback,
 	{
 		sActivities.remove(activity);
 	}
+
+	/**
+	 * Initializes the service state, loading songs saved from the disk into the
+	 * song timeline.
+	 *
+	 * @return The loaded value for mState.
+	 */
+	public int loadState()
+	{
+		int state = 0;
+
+		try {
+			DataInputStream in = new DataInputStream(openFileInput(STATE_FILE));
+
+			if (in.readLong() == STATE_FILE_MAGIC && in.readInt() == STATE_VERSION) {
+				mPendingSeek = in.readInt();
+				mTimeline.readState(in);
+
+				int finishAction = mTimeline.getFinishAction();
+				if (finishAction == SongTimeline.FINISH_RANDOM)
+					state |= FLAG_RANDOM;
+				else if (finishAction == SongTimeline.FINISH_REPEAT)
+					state |= FLAG_REPEAT;
+				if (mTimeline.isShuffling())
+					state |= FLAG_SHUFFLE;
+			}
+
+			in.close();
+		} catch (EOFException e) {
+			Log.w("VanillaMusic", "Failed to load state", e);
+		} catch (IOException e) {
+			Log.w("VanillaMusic", "Failed to load state", e);
+		}
+
+		return state;
+	}
+
+	/**
+	 * Save the service state to disk.
+	 *
+	 * @param pendingSeek The pendingSeek to store. Should be the current
+	 * MediaPlayer position or 0.
+	 */
+	public void saveState(int pendingSeek)
+	{
+		try {
+			DataOutputStream out = new DataOutputStream(openFileOutput(STATE_FILE, 0));
+			out.writeLong(STATE_FILE_MAGIC);
+			out.writeInt(STATE_VERSION);
+			out.writeInt(pendingSeek);
+			mTimeline.writeState(out);
+			out.close();
+		} catch (IOException e) {
+			Log.w("VanillaMusic", "Failed to save state", e);
+		}
+	}
 }

src/org/kreed/vanilla/SongTimeline.java

@@ -36,7 +36,6 @@ import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
 import android.provider.MediaStore;
-import android.util.Log;
 
 /**
  * Represents a series of songs that can be moved through backward or forward.
@@ -82,23 +81,12 @@ public final class SongTimeline {
 	 */
 	public static final int MODE_ENQUEUE = 2;
 
-	/**
-	 * Name of the state file.
-	 */
-	private static final String STATE_FILE = "state";
-	/**
-	 * Header for state file to help indicate if the file is in the right
-	 * format.
-	 */
-	private static final long STATE_FILE_MAGIC = 0xf89daa2fac33L;
-
 	private Context mContext;
-
 	/**
 	 * All the songs currently contained in the timeline. Each Song object
 	 * should be unique, even if it refers to the same media.
 	 */
-	private ArrayList<Song> mSongs;
+	private ArrayList<Song> mSongs = new ArrayList<Song>();
 	/**
 	 * The position of the current song (i.e. the playing song).
 	 */
@@ -176,19 +164,14 @@ public final class SongTimeline {
 	}
 
 	/**
-	 * Initializes the timeline with the state stored in the state file created
+	 * Initializes the timeline with data read from the stream. Data should have
-	 * by a call to save state.
+	 * been saved by a call to {@link SongTimeline#writeState(DataOutputStream)}.
 	 *
-	 * @return The optional extra data, or -1 if loading failed
+	 * @param in The stream to read from.
 	 */
-	public int loadState()
+	public void readState(DataInputStream in) throws IOException, EOFException
 	{
-		int extra = -1;
-
-		try {
 		synchronized (this) {
-				DataInputStream in = new DataInputStream(mContext.openFileInput(STATE_FILE));
-				if (in.readLong() == STATE_FILE_MAGIC) {
 			int n = in.readInt();
 			if (n > 0) {
 				ArrayList<Song> songs = new ArrayList<Song>(n);
@@ -247,36 +230,18 @@ public final class SongTimeline {
 			mCurrentPos = Math.min(mSongs == null ? 0 : mSongs.size(), in.readInt());
 			mFinishAction = in.readInt();
 			mShuffle = in.readBoolean();
-					extra = in.readInt();
-
-					in.close();
 		}
 	}
-		} catch (EOFException e) {
-			Log.w("VanillaMusic", "Failed to load state", e);
-		} catch (IOException e) {
-			Log.w("VanillaMusic", "Failed to load state", e);
-		}
-
-		if (mSongs == null)
-			mSongs = new ArrayList<Song>();
-
-		return extra;
-	}
 
 	/**
-	 * Returns a byte array representing the current state of the timeline.
+	 * Writes the current songs and state to the given stream.
-	 * This can be passed to the appropriate constructor to initialize the
-	 * timeline with this state.
 	 *
-	 * @param extra Optional extra data to be included. Should not be -1.
+	 * @param out The stream to write to.
 	 */
-	public void saveState(int extra)
+	public void writeState(DataOutputStream out) throws IOException
 	{
-		try {
+		// Must update PlaybackService.STATE_VERSION when changing behavior
-			DataOutputStream out = new DataOutputStream(mContext.openFileOutput(STATE_FILE, 0));
+		// here.
-			out.writeLong(STATE_FILE_MAGIC);
-
 		synchronized (this) {
 			ArrayList<Song> songs = mSongs;
 
@@ -297,12 +262,6 @@ public final class SongTimeline {
 			out.writeInt(mCurrentPos);
 			out.writeInt(mFinishAction);
 			out.writeBoolean(mShuffle);
-				out.writeInt(extra);
-			}
-
-			out.close();
-		} catch (IOException e) {
-			Log.w("VanillaMusic", "Failed to save state", e);
 		}
 	}