Allow negative struct parent keys in PDFMergerUtility #149
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PDFMergerUtility expects structural parent tree keys to be non-negative. However, negative values don't seem to be forbidden by the specification and are accepted by validators. This patch adapts the class to handle negative struct parent keys correctly.
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Do you have a PDF where this happens? |
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Here is a document to verify the issue. (Sorry, I forgot to add that to the issue in the first place.) |
| @@ -1498,8 +1499,8 @@ private void updateStructParentEntries(PDPage page, int structParentOffset) thro | |||
| List<PDAnnotation> newannots = new ArrayList<>(annots.size()); | |||
| annots.forEach(annot -> | |||
| { | |||
| int structParent = annot.getStructParent(); | |||
| if (structParent >= 0) | |||
| int structParent = annot.getCOSObject().getInt(COSName.STRUCT_PARENT, Integer.MIN_VALUE); // allow for negative struct parent values | |||
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This doesn't change anything but the default value if STRUCT_PARENT is null. If Integer.MIN_VALUE makes more sense than -1 the getter should be changed rather than this piece of code
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I intentionally kept the patch to one class and as simple and minimal as possible, e.g. not renaming variables. So feel free to adapt it and let me know if you have any questions.
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So the question is, do we need to change the default value if the value isn't set?
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That would be an API change which would break all specific (i.e. positiv or negative equals) checks for -1 in all integrations.
If a one-parameter method that defaults to Integer.MIN_VALUE is necessary (IMHO it is not), it would have to be a new one, e.g. getIntSigned(COSName) (and similar for array, possibly for other number types).
The only change in this regard that I consider necessary is improving the API documentation of getInt(COSName) (and similar methods) to clarify that they cannot be used if the result may be negative.
PDFMergerUtility expects structural parent tree keys to be non-negative.
However, negative values don't seem to be forbidden by the specification and are accepted by validators.
This patch adapts the class to handle negative struct parent keys correctly.