am bed703ef: defensive loop guards around cursors.
* commit 'bed703ef28f013639db3cd7a6b8a6e94d61075da':
defensive loop guards around cursors.
diff --git a/src/com/android/dreams/phototable/LocalSource.java b/src/com/android/dreams/phototable/LocalSource.java
index 1faf589..4efc43b 100644
--- a/src/com/android/dreams/phototable/LocalSource.java
+++ b/src/com/android/dreams/phototable/LocalSource.java
@@ -36,14 +36,14 @@
private final String mUnknownAlbumName;
private final String mLocalSourceName;
private Set<String> mFoundAlbumIds;
- private int mNextPosition;
+ private int mLastPosition;
public LocalSource(Context context, SharedPreferences settings) {
super(context, settings);
mLocalSourceName = mResources.getString(R.string.local_source_name, "Photos on Device");
mUnknownAlbumName = mResources.getString(R.string.unknown_album_name, "Unknown");
mSourceName = TAG;
- mNextPosition = -1;
+ mLastPosition = INVALID;
fillQueue();
}
@@ -65,7 +65,7 @@
Cursor cursor = mResolver.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
projection, null, null, null);
if (cursor != null) {
- cursor.moveToFirst();
+ cursor.moveToPosition(-1);
int dataIndex = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
int bucketIndex = cursor.getColumnIndex(MediaStore.Images.Media.BUCKET_ID);
@@ -75,7 +75,7 @@
if (bucketIndex < 0) {
log(TAG, "can't find the ID column!");
} else {
- while (!cursor.isAfterLast()) {
+ while (cursor.moveToNext()) {
String id = TAG + ":" + cursor.getString(bucketIndex);
AlbumData data = foundAlbums.get(id);
if (foundAlbums.get(id) == null) {
@@ -102,7 +102,6 @@
updated :
Math.min(data.updated, updated));
}
- cursor.moveToNext();
}
}
cursor.close();
@@ -139,13 +138,10 @@
Cursor cursor = mResolver.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
projection, selection, null, null);
if (cursor != null) {
- if (cursor.getCount() > howMany && mNextPosition == -1) {
- mNextPosition = mRNG.nextInt() % (cursor.getCount() - howMany);
+ if (cursor.getCount() > howMany && mLastPosition == INVALID) {
+ mLastPosition = pickRandomStart(cursor.getCount(), howMany);
}
- if (mNextPosition == -1) {
- mNextPosition = 0;
- }
- cursor.moveToPosition(mNextPosition);
+ cursor.moveToPosition(mLastPosition);
int dataIndex = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
int orientationIndex = cursor.getColumnIndex(MediaStore.Images.Media.ORIENTATION);
@@ -155,17 +151,18 @@
if (dataIndex < 0) {
log(TAG, "can't find the DATA column!");
} else {
- while (foundImages.size() < howMany && !cursor.isAfterLast()) {
+ while (foundImages.size() < howMany && cursor.moveToNext()) {
ImageData data = new ImageData();
data.url = cursor.getString(dataIndex);
data.orientation = cursor.getInt(orientationIndex);
foundImages.offer(data);
- if (cursor.moveToNext()) {
- mNextPosition++;
- }
+ mLastPosition = cursor.getPosition();
}
if (cursor.isAfterLast()) {
- mNextPosition = 0;
+ mLastPosition = -1;
+ }
+ if (cursor.isBeforeFirst()) {
+ mLastPosition = INVALID;
}
}
diff --git a/src/com/android/dreams/phototable/PhotoSource.java b/src/com/android/dreams/phototable/PhotoSource.java
index 670bd02..32d41c7 100644
--- a/src/com/android/dreams/phototable/PhotoSource.java
+++ b/src/com/android/dreams/phototable/PhotoSource.java
@@ -43,6 +43,9 @@
private static final String TAG = "PhotoTable.PhotoSource";
private static final boolean DEBUG = false;
+ // An invalid cursor position to represent the uninitialized state.
+ protected static final int INVALID = -2;
+
// This should be large enough for BitmapFactory to decode the header so
// that we can mark and reset the input stream to avoid duplicate network i/o
private static final int BUFFER_SIZE = 128 * 1024;
@@ -248,6 +251,14 @@
}
}
+ protected int pickRandomStart(int total, int max) {
+ if (max >= total) {
+ return -1;
+ } else {
+ return (mRNG.nextInt() % (total - max)) - 1;
+ }
+ }
+
protected abstract InputStream getStream(ImageData data, int longSide);
protected abstract Collection<ImageData> findImages(int howMany);
public abstract Collection<AlbumData> findAlbums();
diff --git a/src/com/android/dreams/phototable/PicasaSource.java b/src/com/android/dreams/phototable/PicasaSource.java
index 9513d3c..ef4a7c4 100644
--- a/src/com/android/dreams/phototable/PicasaSource.java
+++ b/src/com/android/dreams/phototable/PicasaSource.java
@@ -75,13 +75,13 @@
private final int mMaxRecycleSize;
private Set<String> mFoundAlbumIds;
- private int mNextPosition;
+ private int mLastPosition;
private int mDisplayLongSide;
public PicasaSource(Context context, SharedPreferences settings) {
super(context, settings);
mSourceName = TAG;
- mNextPosition = -1;
+ mLastPosition = INVALID;
mMaxPostAblums = mResources.getInteger(R.integer.max_post_albums);
mPostsAlbumName = mResources.getString(R.string.posts_album_name, "Posts");
mUploadsAlbumName = mResources.getString(R.string.uploads_album_name, "Instant Uploads");
@@ -162,15 +162,12 @@
Cursor cursor = mResolver.query(picasaUriBuilder.build(),
projection, selection.toString(), null, null);
if (cursor != null) {
- if (cursor.getCount() > howMany && mNextPosition == -1) {
- mNextPosition =
- (int) Math.abs(mRNG.nextInt() % (cursor.getCount() - howMany));
+ if (cursor.getCount() > howMany && mLastPosition == INVALID) {
+ mLastPosition = pickRandomStart(cursor.getCount(), howMany);
}
- if (mNextPosition == -1) {
- mNextPosition = 0;
- }
- log(TAG, "moving to position: " + mNextPosition);
- cursor.moveToPosition(mNextPosition);
+
+ log(TAG, "moving to position: " + mLastPosition);
+ cursor.moveToPosition(mLastPosition);
int idIndex = cursor.getColumnIndex(PICASA_ID);
int urlIndex = cursor.getColumnIndex(PICASA_URL);
@@ -180,7 +177,7 @@
if (idIndex < 0) {
log(TAG, "can't find the ID column!");
} else {
- while (foundImages.size() < howMany && !cursor.isAfterLast()) {
+ while (cursor.moveToNext()) {
if (idIndex >= 0) {
ImageData data = new ImageData();
data.id = cursor.getString(idIndex);
@@ -191,12 +188,13 @@
foundImages.offer(data);
}
- if (cursor.moveToNext()) {
- mNextPosition++;
- }
+ mLastPosition = cursor.getPosition();
}
if (cursor.isAfterLast()) {
- mNextPosition = 0;
+ mLastPosition = -1;
+ }
+ if (cursor.isBeforeFirst()) {
+ mLastPosition = INVALID;
}
}
@@ -254,7 +252,7 @@
projection, selection, null, order);
if (cursor != null) {
log(TAG, " " + id + " resolved to " + cursor.getCount() + " albums");
- cursor.moveToFirst();
+ cursor.moveToPosition(-1);
int idIndex = cursor.getColumnIndex(PICASA_ID);
int typeIndex = cursor.getColumnIndex(PICASA_ALBUM_TYPE);
@@ -262,9 +260,8 @@
if (idIndex < 0) {
log(TAG, "can't find the ID column!");
} else {
- while (!cursor.isAfterLast()) {
+ while (cursor.moveToNext()) {
albumIds.add(cursor.getString(idIndex));
- cursor.moveToNext();
}
}
cursor.close();
@@ -296,7 +293,7 @@
Cursor cursor = mResolver.query(picasaUriBuilder.build(),
projection, null, null, null);
if (cursor != null) {
- cursor.moveToFirst();
+ cursor.moveToPosition(-1);
int idIndex = cursor.getColumnIndex(PICASA_ID);
int thumbIndex = cursor.getColumnIndex(PICASA_THUMB);
@@ -308,7 +305,7 @@
if (idIndex < 0) {
log(TAG, "can't find the ID column!");
} else {
- while (!cursor.isAfterLast()) {
+ while (cursor.moveToNext()) {
String id = TAG + ":" + cursor.getString(idIndex);
String user = (userIndex >= 0 ? cursor.getString(userIndex) : "-1");
String type = (typeIndex >= 0 ? cursor.getString(typeIndex) : "none");
@@ -367,8 +364,6 @@
if (data.thumbnailUrl == null || data.updated == updated) {
data.thumbnailUrl = thumbnailUrl;
}
-
- cursor.moveToNext();
}
}
cursor.close();
