Now that only the second container can send JSON-encoded progress
information, we can the untrusted JSON parsing. The parse_progress was
also renamed to `parse_progress_trusted` to ensure future developers
don't mistake this as a safe method.
The old methods for sending untrusted JSON were repurposed to send the
progress instead to stderr for troubleshooting in development mode.
Fixes#456
Merge Qubes and Containers isolation providers core code into the class
parent IsolationProviders abstract class.
This is done by streaming pages in containers for exclusively in first
conversion process. The commit is rather large due to the multiple
interdependencies of the code, making it difficult to split into various
commits.
The main conversion method (_convert) now in the superclass simply calls
two methods:
- doc_to_pixels()
- pixels_to_pdf()
Critically, doc_to_pixels is implemented in the superclass, diverging
only in a specialized method called "start_doc_to_pixels_proc()". This
method obtains the process responsible that communicates with the
isolation provider (container / disp VM) via `podman/docker` and qrexec
on Containers and Qubes respectively.
Known regressions:
- progress reports stopped working on containers
Fixes#443
Theoretically the max pages would be 65536 (2byte unsigned int.
However this limit is much higher than practical documents have
and larger ones can lead to unforseen problems, for example RAM
limitations.
We thus opted to use a lower limit of 10K. The limit must be
detected client-side, given that the server is distrusted. However
we also check it in the server, just as a fail-early mechanism.
Isolation provider tests done in tests/test_base.py and had
pytest.mark.parameterize() for each isolation provider. This logic
would not work well when we had test that diverge. We could have marked
each one as compatible with one provider or another, but in the end it
turned out to be better to have the common ones in a base class and
the divergent ones in each.
NOTE: this has a strange side-effect: inherited test classes need to
have imports for all of the fixtures even if they are not explictly used
