Memoizer: ask any ImageReader instances to remove all but the current reader

Author: melissalinkert

components/formats-api/src/loci/formats/ImageReader.java

@@ -150,6 +150,24 @@ public ImageReader(ClassList<IFormatReader> classList) {
 
   // -- ImageReader API methods --
 
+  /**
+   * Intended for use prior to caching an initialized reader.
+   * This removes everything except the current reader from the
+   * list of possible readers to use. Be very careful, and do
+   * not call this method on an ImageReader that may be reused
+   * for multiple different files.
+   *
+   * If the current reader index is less than 0 (i.e. not initialized),
+   * this does nothing.
+   */
+  protected void cleanupReaderList() {
+    if (current >= 0) {
+      IFormatReader currentReader = readers[current];
+      current = 0;
+      readers = new IFormatReader[] {currentReader};
+    }
+  }
+
   /**
    * Toggles whether or not file system access is allowed when doing type
    * detection.  By default, file system access is allowed.

components/formats-bsd/src/loci/formats/Memoizer.java

@@ -208,6 +208,17 @@ public void saveRevision(String revision) {
 
     @Override
     public void saveReader(IFormatReader reader) {
+      // clean up reader list in any instances of ImageReader
+      IFormatReader r = reader;
+      while (r instanceof ReaderWrapper || r instanceof ImageReader) {
+        if (r instanceof ImageReader) {
+          ImageReader ir = (ImageReader) r;
+          ir.cleanupReaderList();
+          r = ir.getReader();
+        }
+        else r = ((ReaderWrapper) r).getReader();
+      }
+
       kryo.writeObject(output, reader.getClass());
       kryo.writeObject(output, reader);
     }