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sshpeer: initial definition and implementation of new SSH protocol...
sshpeer: initial definition and implementation of new SSH protocol The existing SSH protocol has several design flaws. Future commits will elaborate on these flaws as new features are introduced to combat these flaws. For now, hopefully you can take me for my word that a ground up rewrite of the SSH protocol is needed. This commit lays the foundation for a new SSH protocol by defining a mechanism to upgrade the SSH transport channel away from the default (version 1) protocol to something modern (which we'll call "version 2" for now). This upgrade process is detailed in the internals documentation for the wire protocol. The gist of it is the client sends a request line preceding the "hello" command/line which basically says "I'm requesting an upgrade: here's what I support." If the server recognizes that line, it processes the upgrade request and the transport channel is switched to use the new version of the protocol. If not, it sends an empty response, which is how all Mercurial SSH servers from the beginning of time reacted to unknown commands. The upgrade request is effectively ignored and the client continues to use the existing version of the protocol as if nothing happened. The new version of the SSH protocol is completely identical to version 1 aside from the upgrade dance and the bytes that follow. The immediate bytes that follow the protocol switch are defined to be a length framed "capabilities: " line containing the remote's advertised capabilities. In reality, this looks very similar to what the "hello" response would look like. But it will evolve quickly. The methodology by which the protocol will evolve is important. I'm not going to introduce the new protocol all at once. That would likely lead to endless bike shedding and forward progress would stall. Instead, I intend to tricle out new features and diversions from the existing protocol in small, incremental changes. To support the gradual evolution of the protocol, the on-the-wire advertised protocol name contains an "exp" to denote "experimental" and a 4 digit field to capture the sub-version of the protocol. Whenever we make a BC change to the wire protocol, we can increment this version and lock out all older clients because it will appear as a completely different protocol version. This means we can incur as many breaking changes as we want. We don't have to commit to supporting any one feature or idea for a long period of time. We can even evolve the handshake mechanism, because that is defined as being an implementation detail of the negotiated protocol version! Hopefully this lowers the barrier to accepting changes to the protocol and for experimenting with "radical" ideas during its development. In core, sshpeer received most of the attention. We haven't even implemented the server bits for the new protocol in core yet. Instead, we add very primitive support to our test server, mainly just to exercise the added code paths in sshpeer. Differential Revision: https://phab.mercurial-scm.org/D2061 # no-check-commit because of required foo_bar naming

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test-minirst.py
267 lines | 5.3 KiB | text/x-python | PythonLexer
from __future__ import absolute_import, print_function
import pprint
from mercurial import (
minirst,
)
def debugformat(text, form, **kwargs):
if form == 'html':
print("html format:")
out = minirst.format(text, style=form, **kwargs)
else:
print("%d column format:" % form)
out = minirst.format(text, width=form, **kwargs)
print("-" * 70)
if type(out) == tuple:
print(out[0][:-1])
print("-" * 70)
pprint.pprint(out[1])
else:
print(out[:-1])
print("-" * 70)
print()
def debugformats(title, text, **kwargs):
print("== %s ==" % title)
debugformat(text, 60, **kwargs)
debugformat(text, 30, **kwargs)
debugformat(text, 'html', **kwargs)
paragraphs = """
This is some text in the first paragraph.
A small indented paragraph.
It is followed by some lines
containing random whitespace.
\n \n \nThe third and final paragraph.
"""
debugformats('paragraphs', paragraphs)
definitions = """
A Term
Definition. The indented
lines make up the definition.
Another Term
Another definition. The final line in the
definition determines the indentation, so
this will be indented with four spaces.
A Nested/Indented Term
Definition.
"""
debugformats('definitions', definitions)
literals = r"""
The fully minimized form is the most
convenient form::
Hello
literal
world
In the partially minimized form a paragraph
simply ends with space-double-colon. ::
////////////////////////////////////////
long un-wrapped line in a literal block
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
::
This literal block is started with '::',
the so-called expanded form. The paragraph
with '::' disappears in the final output.
"""
debugformats('literals', literals)
lists = """
- This is the first list item.
Second paragraph in the first list item.
- List items need not be separated
by a blank line.
- And will be rendered without
one in any case.
We can have indented lists:
- This is an indented list item
- Another indented list item::
- A literal block in the middle
of an indented list.
(The above is not a list item since we are in the literal block.)
::
Literal block with no indentation (apart from
the two spaces added to all literal blocks).
1. This is an enumerated list (first item).
2. Continuing with the second item.
(1) foo
(2) bar
1) Another
2) List
Line blocks are also a form of list:
| This is the first line.
The line continues here.
| This is the second line.
Bullet lists are also detected:
* This is the first bullet
* This is the second bullet
It has 2 lines
* This is the third bullet
"""
debugformats('lists', lists)
options = """
There is support for simple option lists,
but only with long options:
-X, --exclude filter an option with a short and long option with an argument
-I, --include an option with both a short option and a long option
--all Output all.
--both Output both (this description is
quite long).
--long Output all day long.
--par This option has two paragraphs in its description.
This is the first.
This is the second. Blank lines may be omitted between
options (as above) or left in (as here).
The next paragraph looks like an option list, but lacks the two-space
marker after the option. It is treated as a normal paragraph:
--foo bar baz
"""
debugformats('options', options)
fields = """
:a: First item.
:ab: Second item. Indentation and wrapping
is handled automatically.
Next list:
:small: The larger key below triggers full indentation here.
:much too large: This key is big enough to get its own line.
"""
debugformats('fields', fields)
containers = """
Normal output.
.. container:: debug
Initial debug output.
.. container:: verbose
Verbose output.
.. container:: debug
Debug output.
"""
debugformats('containers (normal)', containers)
debugformats('containers (verbose)', containers, keep=['verbose'])
debugformats('containers (debug)', containers, keep=['debug'])
debugformats('containers (verbose debug)', containers,
keep=['verbose', 'debug'])
roles = """Please see :hg:`add`."""
debugformats('roles', roles)
sections = """
Title
=====
Section
-------
Subsection
''''''''''
Markup: ``foo`` and :hg:`help`
------------------------------
"""
debugformats('sections', sections)
admonitions = """
.. note::
This is a note
- Bullet 1
- Bullet 2
.. warning:: This is a warning Second
input line of warning
.. danger::
This is danger
"""
debugformats('admonitions', admonitions)
comments = """
Some text.
.. A comment
.. An indented comment
Some indented text.
..
Empty comment above
"""
debugformats('comments', comments)
data = [['a', 'b', 'c'],
['1', '2', '3'],
['foo', 'bar', 'baz this list is very very very long man']]
rst = minirst.maketable(data, 2, True)
table = ''.join(rst)
print(table)
debugformats('table', table)
data = [['s', 'long', 'line\ngoes on here'],
['', 'xy', 'tried to fix here\n by indenting']]
rst = minirst.maketable(data, 1, False)
table = ''.join(rst)
print(table)
debugformats('table+nl', table)