Handling Corrupt Tile Cache

[JackPGreen]

I ran out of disk space while in the middle of caching a tile, which caused the cached tile to become corrupted (which is fine).

When I then tried to retrieve the tile from the cache, I get the following error (below).

The problem is that that this error isn't thrown - it's caught and printed to the console internally in Mapsforge.

In addition, with a regular tile cache setup, because the tilecache contains a value for this job (even though it's corrupt), it's never replaced.

I think the default behaviour should not be to print exceptions to the console, and if this error occurs then it should be rethrown and the corrupt tile removed from the cache.

java.lang.IndexOutOfBoundsException: off < 0 || len < 0 || off+len > b.length || off+len < 0!
at javax.imageio.stream.FileCacheImageInputStream.read(FileCacheImageInputStream.java:177)
at com.sun.imageio.plugins.common.SubImageInputStream.read(SubImageInputStream.java:61)
at com.sun.imageio.plugins.common.InputStreamAdapter.read(InputStreamAdapter.java:47)
at java.io.SequenceInputStream.read(SequenceInputStream.java:208)
at java.io.SequenceInputStream.read(SequenceInputStream.java:211)
at java.util.zip.InflaterInputStream.fill(InflaterInputStream.java:238)
at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:158)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:235)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:275)
at java.io.BufferedInputStream.read(BufferedInputStream.java:334)
at java.io.DataInputStream.readFully(DataInputStream.java:195)
at com.sun.imageio.plugins.png.PNGImageReader.decodePass(PNGImageReader.java:1092)
at com.sun.imageio.plugins.png.PNGImageReader.decodeImage(PNGImageReader.java:1196)
at com.sun.imageio.plugins.png.PNGImageReader.readImage(PNGImageReader.java:1301)
at com.sun.imageio.plugins.png.PNGImageReader.read(PNGImageReader.java:1577)
at javax.imageio.ImageIO.read(ImageIO.java:1448)
at javax.imageio.ImageIO.read(ImageIO.java:1352)
at org.mapsforge.map.awt.graphics.AwtBitmap.(AwtBitmap.java:36)
at org.mapsforge.map.awt.graphics.AwtTileBitmap.(AwtTileBitmap.java:33)
at org.mapsforge.map.awt.graphics.AwtGraphicFactory.createTileBitmap(AwtGraphicFactory.java:203)
at org.mapsforge.map.layer.cache.FileSystemTileCache.get(FileSystemTileCache.java:254)

[devemux86]

A re-throw can crash the app, should be handled internally there like mentioned by clearing any bad one and request again the tile.
Though looking at FileSystemTileCache in case of errors the job is removed and return null to trigger a reload of the tile.

[JackPGreen]

For reference this was with 0.9.1

[devemux86]

Can discuss in forum and if there is interest from community to contribute.