procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/usr/bin/env python
"""This does HTTP GET requests given a host:port and path and returns
a subset of the headers plus the body of the result."""
import argparse
import json
import os
import sys
from mercurial import (
pycompat,
util,
)
httplib = util.httplib
try:
import msvcrt
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
pass
stdout = getattr(sys.stdout, 'buffer', sys.stdout)
parser = argparse.ArgumentParser()
parser.add_argument('--twice', action='store_true')
parser.add_argument('--headeronly', action='store_true')
parser.add_argument('--json', action='store_true')
parser.add_argument('--hgproto')
parser.add_argument(
'--requestheader',
nargs='*',
default=[],
help='Send an additional HTTP request header. Argument '
'value is <header>=<value>',
)
parser.add_argument('--bodyfile', help='Write HTTP response body to a file')
parser.add_argument('host')
parser.add_argument('path')
parser.add_argument('show', nargs='*')
args = parser.parse_args()
twice = args.twice
headeronly = args.headeronly
formatjson = args.json
hgproto = args.hgproto
requestheaders = args.requestheader
tag = None
def request(host, path, show):
assert not path.startswith('/'), path
global tag
headers = {}
if tag:
headers['If-None-Match'] = tag
if hgproto:
headers['X-HgProto-1'] = hgproto
for header in requestheaders:
key, value = header.split('=', 1)
headers[key] = value
conn = httplib.HTTPConnection(host)
conn.request("GET", '/' + path, None, headers)
response = conn.getresponse()
stdout.write(
b'%d %s\n' % (response.status, response.reason.encode('ascii'))
)
if show[:1] == ['-']:
show = sorted(
h for h, v in response.getheaders() if h.lower() not in show
)
for h in [h.lower() for h in show]:
if response.getheader(h, None) is not None:
stdout.write(
b"%s: %s\n"
% (h.encode('ascii'), response.getheader(h).encode('ascii'))
)
if headeronly:
# still read the body to prevent windows to be unhappy about that
# (this might some flakyness in test-hgweb-filelog.t on Windows)
data = response.read()
else:
stdout.write(b'\n')
data = response.read()
if args.bodyfile:
bodyfh = open(args.bodyfile, 'wb')
else:
bodyfh = stdout
# Pretty print JSON. This also has the beneficial side-effect
# of verifying emitted JSON is well-formed.
if formatjson:
# json.dumps() will print trailing newlines. Eliminate them
# to make tests easier to write.
data = pycompat.json_loads(data)
lines = json.dumps(data, sort_keys=True, indent=2).splitlines()
for line in lines:
bodyfh.write(pycompat.sysbytes(line.rstrip()))
bodyfh.write(b'\n')
else:
bodyfh.write(data)
if args.bodyfile:
bodyfh.close()
if twice and response.getheader('ETag', None):
tag = response.getheader('ETag')
# further try to please the windows-flakyness deity
conn.close()
return response.status
status = request(args.host, args.path, args.show)
if twice:
status = request(args.host, args.path, args.show)
if 200 <= status <= 305:
sys.exit(0)
sys.exit(1)