"Unexplained problem" while patching

[JoeyGH]

I have two files:

OldFile.txt with content:

Text.

NewFile.txt with content:

New text.
Text.

Then I run the example provided in readme:

import librsync

dst = file('OldFile.txt', 'rb')
src = file('NewFile.txt', 'rb')
synced = file('Synced.txt', 'wb')

signature = librsync.signature(dst)
delta = librsync.delta(src, signature)
librsync.patch(dst, delta, synced)

And get the following error:

Traceback (most recent call last):
  File "_ctypes/callbacks.c", line 314, in 'calling callback function'
TypeError: read_cb() takes exactly 3 arguments (4 given)
python: ERROR: (rs_job_complete) patch job failed: unexplained problem
Traceback (most recent call last):
  File "RsyncTest.py", line 12, in <module>
    librsync.patch(dst, delta, synced)
  File "/usr/local/lib/python2.7/dist-packages/librsync/__init__.py", line 113, in wrapper
    return f(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/librsync/__init__.py", line 228, in patch
    _execute(job, d, o)
  File "/usr/local/lib/python2.7/dist-packages/librsync/__init__.py", line 141, in _execute
    raise LibrsyncError(r)
librsync.LibrsyncError: unexplained problem

I tried syncing many different files and all went well, but this one case just won't work.

[btimby]

I added a unit test with your data files. I fixed the unexplained problem which was that the read callback did not match the expected function signature. The first opaque parameter was missing.

The test case still fails as the data being read by the callback is not properly returned. There is a stray pointer, the buffer is the correct length, but is seemingly random data.