Architecture

pikepdf uses pybind11 to bind the C++ interface of QPDF. pybind11 was selected after evaluating Cython, CFFI and SWIG as possible binding solutions.

In addition to bindings pikepdf includes support code written in a mix of C++ and Python, mainly to present a clean Pythonic interface to C++ and implement higher level functionality.

Internals

Internally the package presents a module named pikepdf from which objects can be imported. The C++ extension module is currently named pikepdf._qpdf. Users of pikepdf should not directly access _qpdf since it is an internal interface.

Thread safety

Because of the global interpreter lock (GIL), it is safe to read pikepdf objects across Python threads. Also because of the GIL, there may not be much performance gain from doing so.

If one or more threads will be modifying pikepdf objects, you will have to coordinate read and write access with a threading.Lock.

It is not currently possible to pickle pikepdf objects or marshall them across process boundaries (as would be required to use pikepdf in multiprocessing). If this were implemented, it would not be much more efficient than saving a full PDF and sending it to another process.