Avoid stack overflow #198
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Avoid stack overflow #198
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This single page PDF has a Form XObject in its Resources dict. The Form XObject has its own Resources dict, which has an XObject pointing to itself. Nested XObjects are fine, but not recursive ones. This is a simpler file that demonstrates an issue originally found in the PDF provided at [1] [1] #94 (comment)
Given an input collection like so:
a = [1, b]
b = [2, c]
c = [3, a]
ObjectHash#deref!(a) should return the correct value without falling
into an endless loop that overflows the stack.
Similar data structures are possible with Hash's and Streams, so we have
to jump through hoops for them too.
The seen arg is purely for internal use, and exists to avoid endless loops in the recursion. Arranging the methods this way means the arg wont be visible in the public API
This was referenced Feb 12, 2017
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This is an alternative solution to #195. This version is messier and less elegant, but more correct. Assuming it builds green, I'm inclined to merge this one instead and refactor later with the safety of the new specs.
deref!was added in 9c520b6 and attempts to return a deep object graph that contains noPDF::Reader::Referenceobjects and can be walked without risk of needing to refer back to the associatedObjectHashinstance.This change resolves a recursion bug that can occur in real world files