view mercurial/httpclient/_readers.py @ 23575:a2f139d25845

subrepo: drop the 'ui' parameter to archive()

The current state of subrepo methods is to pass a 'ui' object to some methods,
which has the effect of overriding the subrepo configuration since it is the
root repo's 'ui' that is passed along as deep as there are subrepos.  Other
subrepo method are *not* passed the root 'ui', and instead delegate to their
repo object's 'ui'.  Even in the former case where the root 'ui' is available,
some methods are inconsistent in their use of both the root 'ui' and the local
repo's 'ui'.  (Consider hg._incoming() uses the root 'ui' for path expansion
and some status messages, but also calls bundlerepo.getremotechanges(), which
eventually calls discovery.findcommonincoming(), which calls
setdiscovery.findcommonheads(), which calls status() on the local repo 'ui'.)

This inconsistency with respect to the configured output level is probably
always hidden, because --verbose, --debug and --quiet, along with their 'ui.xxx'
equivalents in the global and user level hgrc files are propagated from the
parent repo to the subrepo via 'baseui'.  The 'ui.xxx' settings in the parent
repo hgrc file are not propagated, but that seems like an unusual thing to set
on a per repo config file.  Any 'ui.xxx' options changed by --config are also
not propagated, because they are set on repo.ui by dispatch.py, not repo.baseui.

The goal here is to cleanup the subrepo methods by dropping the 'ui' parameter,
which in turn prevents mixing subtly different 'ui' instances on a given subrepo
level.  Some methods use more than just the output level settings in 'ui' (add
for example ends up calling scmutil.checkportabilityalert() with both the root
and local repo's 'ui' at different points).  This series just goes for the low
hanging fruit and switches methods that only use the output level.

If we really care about not letting a subrepo config override the root repo's
output level, we can propagate the verbose, debug and quiet settings to the
subrepo in the same way 'ui.commitsubrepos' is in hgsubrepo.__init__.

Archive only uses the 'ui' object to call its progress() method, and gitsubrepo
calls status().

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"""Reader objects to abstract out different body response types.

This module is package-private. It is not expected that these will
have any clients outside of httpplus.
"""

import httplib
import logging

logger = logging.getLogger(__name__)


class ReadNotReady(Exception):
    """Raised when read() is attempted but not enough data is loaded."""


class HTTPRemoteClosedError(httplib.HTTPException):
    """The server closed the remote socket in the middle of a response."""


class AbstractReader(object):
    """Abstract base class for response readers.

    Subclasses must implement _load, and should implement _close if
    it's not an error for the server to close their socket without
    some termination condition being detected during _load.
    """
    def __init__(self):
        self._finished = False
        self._done_chunks = []
        self.available_data = 0

    def _addchunk(self, data):
        self._done_chunks.append(data)
        self.available_data += len(data)

    def _pushchunk(self, data):
        self._done_chunks.insert(0, data)
        self.available_data += len(data)

    def _popchunk(self):
        b = self._done_chunks.pop(0)
        self.available_data -= len(b)

        return b

    def done(self):
        """Returns true if the response body is entirely read."""
        return self._finished

    def read(self, amt):
        """Read amt bytes from the response body."""
        if self.available_data < amt and not self._finished:
            raise ReadNotReady()
        blocks = []
        need = amt
        while self._done_chunks:
            b = self._popchunk()
            if len(b) > need:
                nb = b[:need]
                self._pushchunk(b[need:])
                b = nb
            blocks.append(b)
            need -= len(b)
            if need == 0:
                break
        result = ''.join(blocks)
        assert len(result) == amt or (self._finished and len(result) < amt)

        return result

    def readto(self, delimstr, blocks = None):
        """return available data chunks up to the first one in which delimstr
        occurs. No data will be returned after delimstr -- the chunk in which
        it occurs will be split and the remainder pushed back onto the available
        data queue. If blocks is supplied chunks will be added to blocks, otherwise
        a new list will be allocated.
        """
        if blocks is None:
            blocks = []

        while self._done_chunks:
            b = self._popchunk()
            i = b.find(delimstr) + len(delimstr)
            if i:
                if i < len(b):
                    self._pushchunk(b[i:])
                blocks.append(b[:i])
                break
            else:
                blocks.append(b)

        return blocks

    def _load(self, data): # pragma: no cover
        """Subclasses must implement this.

        As data is available to be read out of this object, it should
        be placed into the _done_chunks list. Subclasses should not
        rely on data remaining in _done_chunks forever, as it may be
        reaped if the client is parsing data as it comes in.
        """
        raise NotImplementedError

    def _close(self):
        """Default implementation of close.

        The default implementation assumes that the reader will mark
        the response as finished on the _finished attribute once the
        entire response body has been read. In the event that this is
        not true, the subclass should override the implementation of
        close (for example, close-is-end responses have to set
        self._finished in the close handler.)
        """
        if not self._finished:
            raise HTTPRemoteClosedError(
                'server appears to have closed the socket mid-response')


class AbstractSimpleReader(AbstractReader):
    """Abstract base class for simple readers that require no response decoding.

    Examples of such responses are Connection: Close (close-is-end)
    and responses that specify a content length.
    """
    def _load(self, data):
        if data:
            assert not self._finished, (
                'tried to add data (%r) to a closed reader!' % data)
        logger.debug('%s read an additional %d data',
                     self.name, len(data)) # pylint: disable=E1101
        self._addchunk(data)


class CloseIsEndReader(AbstractSimpleReader):
    """Reader for responses that specify Connection: Close for length."""
    name = 'close-is-end'

    def _close(self):
        logger.info('Marking close-is-end reader as closed.')
        self._finished = True


class ContentLengthReader(AbstractSimpleReader):
    """Reader for responses that specify an exact content length."""
    name = 'content-length'

    def __init__(self, amount):
        AbstractSimpleReader.__init__(self)
        self._amount = amount
        if amount == 0:
            self._finished = True
        self._amount_seen = 0

    def _load(self, data):
        AbstractSimpleReader._load(self, data)
        self._amount_seen += len(data)
        if self._amount_seen >= self._amount:
            self._finished = True
            logger.debug('content-length read complete')


class ChunkedReader(AbstractReader):
    """Reader for chunked transfer encoding responses."""
    def __init__(self, eol):
        AbstractReader.__init__(self)
        self._eol = eol
        self._leftover_skip_amt = 0
        self._leftover_data = ''

    def _load(self, data):
        assert not self._finished, 'tried to add data to a closed reader!'
        logger.debug('chunked read an additional %d data', len(data))
        position = 0
        if self._leftover_data:
            logger.debug(
                'chunked reader trying to finish block from leftover data')
            # TODO: avoid this string concatenation if possible
            data = self._leftover_data + data
            position = self._leftover_skip_amt
            self._leftover_data = ''
            self._leftover_skip_amt = 0
        datalen = len(data)
        while position < datalen:
            split = data.find(self._eol, position)
            if split == -1:
                self._leftover_data = data
                self._leftover_skip_amt = position
                return
            amt = int(data[position:split], base=16)
            block_start = split + len(self._eol)
            # If the whole data chunk plus the eol trailer hasn't
            # loaded, we'll wait for the next load.
            if block_start + amt + len(self._eol) > len(data):
                self._leftover_data = data
                self._leftover_skip_amt = position
                return
            if amt == 0:
                self._finished = True
                logger.debug('closing chunked reader due to chunk of length 0')
                return
            self._addchunk(data[block_start:block_start + amt])
            position = block_start + amt + len(self._eol)
# no-check-code