from twisted.internet.interfaces import ITransport
from twisted.internet import defer
-from twisted.internet.interfaces import IFinishableConsumer
+from twisted.internet.interfaces import IConsumer
from foolscap.api import eventually
from allmydata.util import deferredutil
class OverwriteableFileConsumer(PrefixingLogMixin):
- implements(IFinishableConsumer)
+ implements(IConsumer)
"""I act both as a consumer for the download of the original file contents, and as a
wrapper for a temporary file that records the downloaded data and any overwrites.
I use a priority queue to keep track of which regions of the file have been overwritten
self.milestones = [] # empty heap of (offset, d)
self.overwrites = [] # empty heap of (start, end)
self.is_closed = False
- self.done = self.when_reached(download_size) # adds a milestone
- self.is_done = False
- def _signal_done(ign):
- if noisy: self.log("DONE", level=NOISY)
- self.is_done = True
- self.done.addCallback(_signal_done)
+
+ self.done = defer.Deferred()
+ self.done_status = None # None -> not complete, Failure -> download failed, str -> download succeeded
self.producer = None
def get_file(self):
self.download_size = size
if self.downloaded >= self.download_size:
- self.finish()
+ self.download_done("size changed")
def registerProducer(self, p, streaming):
if noisy: self.log(".registerProducer(%r, streaming=%r)" % (p, streaming), level=NOISY)
p.resumeProducing()
else:
def _iterate():
- if not self.is_done:
+ if self.done_status is None:
p.resumeProducing()
eventually(_iterate)
_iterate()
return
if noisy: self.log("MILESTONE %r %r" % (next, d), level=NOISY)
heapq.heappop(self.milestones)
- eventually(d.callback, None)
+ eventually_callback(d)("reached")
if milestone >= self.download_size:
- self.finish()
+ self.download_done("reached download size")
def overwrite(self, offset, data):
if noisy: self.log(".overwrite(%r, <data of length %r>)" % (offset, len(data)), level=NOISY)
+ if self.is_closed:
+ self.log("overwrite called on a closed OverwriteableFileConsumer", level=WEIRD)
+ raise SFTPError(FX_BAD_MESSAGE, "cannot write to a closed file handle")
+
if offset > self.current_size:
# Normally writing at an offset beyond the current end-of-file
# would leave a hole that appears filled with zeroes. However, an
The caller must perform no more overwrites until the Deferred has fired."""
if noisy: self.log(".read(%r, %r), current_size = %r" % (offset, length, self.current_size), level=NOISY)
+ if self.is_closed:
+ self.log("read called on a closed OverwriteableFileConsumer", level=WEIRD)
+ raise SFTPError(FX_BAD_MESSAGE, "cannot read from a closed file handle")
# Note that the overwrite method is synchronous. When a write request is processed
# (e.g. a writeChunk request on the async queue of GeneralSFTPFile), overwrite will
if noisy: self.log("truncating read to %r bytes" % (length,), level=NOISY)
needed = min(offset + length, self.download_size)
- d = self.when_reached(needed)
- def _reached(ign):
+
+ # If we fail to reach the needed number of bytes, the read request will fail.
+ d = self.when_reached_or_failed(needed)
+ def _reached_in_read(res):
# It is not necessarily the case that self.downloaded >= needed, because
# the file might have been truncated (thus truncating the download) and
# then extended.
_assert(self.current_size >= offset + length,
current_size=self.current_size, offset=offset, length=length)
- if noisy: self.log("self.f = %r" % (self.f,), level=NOISY)
+ if noisy: self.log("_reached_in_read(%r), self.f = %r" % (res, self.f,), level=NOISY)
self.f.seek(offset)
return self.f.read(length)
- d.addCallback(_reached)
+ d.addCallback(_reached_in_read)
return d
- def when_reached(self, index):
- if noisy: self.log(".when_reached(%r)" % (index,), level=NOISY)
- if index <= self.downloaded: # already reached
- if noisy: self.log("already reached %r" % (index,), level=NOISY)
- return defer.succeed(None)
+ def when_reached_or_failed(self, index):
+ if noisy: self.log(".when_reached_or_failed(%r)" % (index,), level=NOISY)
+ def _reached(res):
+ if noisy: self.log("reached %r with result %r" % (index, res), level=NOISY)
+ return res
+
+ if self.done_status is not None:
+ return defer.execute(_reached, self.done_status)
+ if index <= self.downloaded: # already reached successfully
+ if noisy: self.log("already reached %r successfully" % (index,), level=NOISY)
+ return defer.succeed("already reached successfully")
d = defer.Deferred()
- def _reached(ign):
- if noisy: self.log("reached %r" % (index,), level=NOISY)
- return ign
d.addCallback(_reached)
heapq.heappush(self.milestones, (index, d))
return d
def when_done(self):
- return self.done
+ d = defer.Deferred()
+ self.done.addCallback(lambda ign: eventually_callback(d)(self.done_status))
+ return d
- def finish(self):
- """Called by the producer when it has finished producing, or when we have
- received enough bytes, or as a result of a close. Defined by IFinishableConsumer."""
+ def download_done(self, res):
+ _assert(isinstance(res, (str, Failure)), res=res)
+ # Only the first call to download_done counts, but we log subsequent calls
+ # (multiple calls are normal).
+ if self.done_status is not None:
+ self.log("IGNORING extra call to download_done with result %r; previous result was %r"
+ % (res, self.done_status), level=OPERATIONAL)
+ return
+
+ self.log("DONE with result %r" % (res,), level=OPERATIONAL)
+
+ # We avoid errbacking self.done so that we are not left with an 'Unhandled error in Deferred'
+ # in case when_done() is never called. Instead we stash the failure in self.done_status,
+ # from where the callback added in when_done() can retrieve it.
+ self.done_status = res
+ eventually_callback(self.done)(None)
while len(self.milestones) > 0:
(next, d) = self.milestones[0]
- if noisy: self.log("MILESTONE FINISH %r %r" % (next, d), level=NOISY)
+ if noisy: self.log("MILESTONE FINISH %r %r %r" % (next, d, res), level=NOISY)
heapq.heappop(self.milestones)
# The callback means that the milestone has been reached if
# it is ever going to be. Note that the file may have been
# truncated to before the milestone.
- eventually(d.callback, None)
+ eventually_callback(d)(res)
def close(self):
if not self.is_closed:
self.f.close()
except Exception, e:
self.log("suppressed %r from close of temporary file %r" % (e, self.f), level=WEIRD)
- self.finish()
+ self.download_done("closed")
+ return self.done_status
def unregisterProducer(self):
- pass
+ # This will happen just before our client calls download_done, which will tell
+ # us the outcome of the download; we don't know the outcome at this point.
+ self.producer = None
+ self.log("producer unregistered", level=NOISY)
SIZE_THRESHOLD = 1000
# i.e. we respond with an EOF error iff offset is already at EOF.
if offset >= len(data):
- eventually(d.errback, SFTPError(FX_EOF, "read at or past end of file"))
+ eventually_errback(d)(Failure(SFTPError(FX_EOF, "read at or past end of file")))
else:
- eventually(d.callback, data[offset:offset+length]) # truncated if offset+length > len(data)
+ eventually_callback(d)(data[offset:offset+length]) # truncated if offset+length > len(data)
return data
self.async.addCallbacks(_read, eventually_errback(d))
d.addBoth(_convert_error, request)
if (self.flags & FXF_TRUNC) or not filenode:
# We're either truncating or creating the file, so we don't need the old contents.
self.consumer = OverwriteableFileConsumer(0, tempfile_maker)
- self.consumer.finish()
+ self.consumer.download_done("download not needed")
else:
self.async.addCallback(lambda ignored: filenode.get_best_readable_version())
self.consumer = OverwriteableFileConsumer(download_size, tempfile_maker)
- version.read(self.consumer, 0, None)
+ d = version.read(self.consumer, 0, None)
+ def _finished(res):
+ if not isinstance(res, Failure):
+ res = "download finished"
+ self.consumer.download_done(res)
+ d.addBoth(_finished)
+ # It is correct to drop d here.
self.async.addCallback(_read)
- eventually(self.async.callback, None)
+ eventually_callback(self.async)(None)
if noisy: self.log("open done", level=NOISY)
return self
def _read(ign):
if noisy: self.log("_read in readChunk(%r, %r)" % (offset, length), level=NOISY)
d2 = self.consumer.read(offset, length)
- d2.addCallbacks(eventually_callback(d), eventually_errback(d))
+ d2.addBoth(eventually_callback(d))
# It is correct to drop d2 here.
return None
self.async.addCallbacks(_read, eventually_errback(d))
# don't addErrback to self.async, just allow subsequent async ops to fail.
return defer.succeed(None)
+ def _do_close(self, res, d=None):
+ if noisy: self.log("_do_close(%r)" % (res,), level=NOISY)
+ status = None
+ if self.consumer:
+ status = self.consumer.close()
+
+ # We must close_notify before re-firing self.async.
+ if self.close_notify:
+ self.close_notify(self.userpath, self.parent, self.childname, self)
+
+ if not isinstance(res, Failure) and isinstance(status, Failure):
+ res = status
+
+ if d:
+ eventually_callback(d)(res)
+ elif isinstance(res, Failure):
+ self.log("suppressing %r" % (res,), level=OPERATIONAL)
+
def close(self):
request = ".close()"
self.log(request, level=OPERATIONAL)
self.closed = True
if not (self.flags & (FXF_WRITE | FXF_CREAT)):
- def _readonly_close():
- if self.consumer:
- self.consumer.close()
- return defer.execute(_readonly_close)
+ # We never fail a close of a handle opened only for reading, even if the file
+ # failed to download. (We could not do so deterministically, because it would
+ # depend on whether we reached the point of failure before abandoning the
+ # download.) Any reads that depended on file content that could not be downloaded
+ # will have failed. It is important that we don't close the consumer until
+ # previous read operations have completed.
+ self.async.addBoth(self._do_close)
+ return defer.succeed(None)
# We must capture the abandoned, parent, and childname variables synchronously
# at the close call. This is needed by the correctness arguments in the comments
# it is correct to optimize out the commit if it is False at the close call.
has_changed = self.has_changed
- def _committed(res):
- if noisy: self.log("_committed(%r)" % (res,), level=NOISY)
-
- self.consumer.close()
-
- # We must close_notify before re-firing self.async.
- if self.close_notify:
- self.close_notify(self.userpath, self.parent, self.childname, self)
- return res
-
- def _close(ign):
+ def _commit(ign):
d2 = self.consumer.when_done()
if self.filenode and self.filenode.is_mutable():
- self.log("update mutable file %r childname=%r metadata=%r" % (self.filenode, childname, self.metadata), level=OPERATIONAL)
+ self.log("update mutable file %r childname=%r metadata=%r"
+ % (self.filenode, childname, self.metadata), level=OPERATIONAL)
if self.metadata.get('no-write', False) and not self.filenode.is_readonly():
_assert(parent and childname, parent=parent, childname=childname, metadata=self.metadata)
d2.addCallback(lambda ign: parent.set_metadata_for(childname, self.metadata))
u = FileHandle(self.consumer.get_file(), self.convergence)
return parent.add_file(childname, u, metadata=self.metadata)
d2.addCallback(_add_file)
-
- d2.addBoth(_committed)
return d2
- d = defer.Deferred()
-
# If the file has been abandoned, we don't want the close operation to get "stuck",
- # even if self.async fails to re-fire. Doing the close independently of self.async
- # in that case ensures that dropping an ssh connection is sufficient to abandon
+ # even if self.async fails to re-fire. Completing the close independently of self.async
+ # in that case should ensure that dropping an ssh connection is sufficient to abandon
# any heisenfiles that were not explicitly closed in that connection.
if abandoned or not has_changed:
- d.addCallback(_committed)
+ d = defer.succeed(None)
+ self.async.addBoth(self._do_close)
else:
- self.async.addCallback(_close)
-
- self.async.addCallbacks(eventually_callback(d), eventually_errback(d))
+ d = defer.Deferred()
+ self.async.addCallback(_commit)
+ self.async.addBoth(self._do_close, d)
d.addBoth(_convert_error, request)
return d
# self.filenode might be None, but that's ok.
attrs = _populate_attrs(self.filenode, self.metadata, size=self.consumer.get_current_size())
- eventually(d.callback, attrs)
+ eventually_callback(d)(attrs)
return None
self.async.addCallbacks(_get, eventually_errback(d))
d.addBoth(_convert_error, request)
# TODO: should we refuse to truncate a file opened with FXF_APPEND?
# <http://allmydata.org/trac/tahoe-lafs/ticket/1037#comment:20>
self.consumer.set_current_size(size)
- eventually(d.callback, None)
+ eventually_callback(d)(None)
return None
self.async.addCallbacks(_set, eventually_errback(d))
d.addBoth(_convert_error, request)
projects / tahoe-lafs / tahoe-lafs.git / blobdiff