view tests/test-ui-verbosity.py.out @ 30435:b86a448a2965

zstd: vendor python-zstandard 0.5.0

As the commit message for the previous changeset says, we wish
for zstd to be a 1st class citizen in Mercurial. To make that
happen, we need to enable Python to talk to the zstd C API. And
that requires bindings.

This commit vendors a copy of existing Python bindings. Why do we
need to vendor? As the commit message of the previous commit says,
relying on systems in the wild to have the bindings or zstd present
is a losing proposition. By distributing the zstd and bindings with
Mercurial, we significantly increase our chances that zstd will
work. Since zstd will deliver a better end-user experience by
achieving better performance, this benefits our users. Another
reason is that the Python bindings still aren't stable and the
API is somewhat fluid. While Mercurial could be coded to target
multiple versions of the Python bindings, it is safer to bundle
an explicit, known working version.

The added Python bindings are mostly a fully-featured interface
to the zstd C API. They allow one-shot operations, streaming,
reading and writing from objects implements the file object
protocol, dictionary compression, control over low-level compression
parameters, and more. The Python bindings work on Python 2.6,
2.7, and 3.3+ and have been tested on Linux and Windows. There are
CFFI bindings, but they are lacking compared to the C extension.
Upstream work will be needed before we can support zstd with PyPy.
But it will be possible.

The files added in this commit come from Git commit
e637c1b214d5f869cf8116c550dcae23ec13b677 from
https://github.com/indygreg/python-zstandard and are added without
modifications. Some files from the upstream repository have been
omitted, namely files related to continuous integration.

In the spirit of full disclosure, I'm the maintainer of the
"python-zstandard" project and have authored 100% of the code
added in this commit. Unfortunately, the Python bindings have
not been formally code reviewed by anyone. While I've tested
much of the code thoroughly (I even have tests that fuzz APIs),
there's a good chance there are bugs, memory leaks, not well
thought out APIs, etc. If someone wants to review the code and
send feedback to the GitHub project, it would be greatly
appreciated.

Despite my involvement with both projects, my opinions of code
style differ from Mercurial's. The code in this commit introduces
numerous code style violations in Mercurial's linters. So, the code
is excluded from most lints. However, some violations I agree with.
These have been added to the known violations ignore list for now.

      hgrc settings    command line options      final result   
    quiet verbo debug   quiet verbo debug      quiet verbo debug
 0  False False False   False False False  ->  False False False
 1   True False False   False False False  ->   True False False
 2  False  True False   False False False  ->  False  True False
 3   True  True False   False False False  ->  False False False
 4  False False  True   False False False  ->  False  True  True
 5   True False  True   False False False  ->  False  True  True
 6  False  True  True   False False False  ->  False  True  True
 7   True  True  True   False False False  ->  False  True  True
 8  False False False    True False False  ->   True False False
 9   True False False    True False False  ->   True False False
10  False  True False    True False False  ->   True False False
11   True  True False    True False False  ->   True False False
12  False False  True    True False False  ->   True False False
13   True False  True    True False False  ->   True False False
14  False  True  True    True False False  ->   True False False
15   True  True  True    True False False  ->   True False False
16  False False False   False  True False  ->  False  True False
17   True False False   False  True False  ->  False  True False
18  False  True False   False  True False  ->  False  True False
19   True  True False   False  True False  ->  False  True False
20  False False  True   False  True False  ->  False  True False
21   True False  True   False  True False  ->  False  True False
22  False  True  True   False  True False  ->  False  True False
23   True  True  True   False  True False  ->  False  True False
24  False False False    True  True False  ->  False False False
25   True False False    True  True False  ->  False False False
26  False  True False    True  True False  ->  False False False
27   True  True False    True  True False  ->  False False False
28  False False  True    True  True False  ->  False False False
29   True False  True    True  True False  ->  False False False
30  False  True  True    True  True False  ->  False False False
31   True  True  True    True  True False  ->  False False False
32  False False False   False False  True  ->  False  True  True
33   True False False   False False  True  ->  False  True  True
34  False  True False   False False  True  ->  False  True  True
35   True  True False   False False  True  ->  False  True  True
36  False False  True   False False  True  ->  False  True  True
37   True False  True   False False  True  ->  False  True  True
38  False  True  True   False False  True  ->  False  True  True
39   True  True  True   False False  True  ->  False  True  True
40  False False False    True False  True  ->  False  True  True
41   True False False    True False  True  ->  False  True  True
42  False  True False    True False  True  ->  False  True  True
43   True  True False    True False  True  ->  False  True  True
44  False False  True    True False  True  ->  False  True  True
45   True False  True    True False  True  ->  False  True  True
46  False  True  True    True False  True  ->  False  True  True
47   True  True  True    True False  True  ->  False  True  True
48  False False False   False  True  True  ->  False  True  True
49   True False False   False  True  True  ->  False  True  True
50  False  True False   False  True  True  ->  False  True  True
51   True  True False   False  True  True  ->  False  True  True
52  False False  True   False  True  True  ->  False  True  True
53   True False  True   False  True  True  ->  False  True  True
54  False  True  True   False  True  True  ->  False  True  True
55   True  True  True   False  True  True  ->  False  True  True
56  False False False    True  True  True  ->  False  True  True
57   True False False    True  True  True  ->  False  True  True
58  False  True False    True  True  True  ->  False  True  True
59   True  True False    True  True  True  ->  False  True  True
60  False False  True    True  True  True  ->  False  True  True
61   True False  True    True  True  True  ->  False  True  True
62  False  True  True    True  True  True  ->  False  True  True
63   True  True  True    True  True  True  ->  False  True  True