# Copyright (C) 2005 Canonical Ltd # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA """Transport is an abstraction layer to handle file access. The abstraction is to allow access from the local filesystem, as well as remote (such as http or sftp). """ from bzrlib.trace import mutter from bzrlib.errors import (BzrError, TransportError, TransportNotPossible, NonRelativePath, NoSuchFile, FileExists, PermissionDenied, ConnectionReset) _protocol_handlers = { } def register_transport(prefix, klass, override=True): global _protocol_handlers # trace messages commented out because they're typically # run during import before trace is set up if _protocol_handlers.has_key(prefix): if override: ## mutter('overriding transport: %s => %s' % (prefix, klass.__name__)) _protocol_handlers[prefix] = klass else: ## mutter('registering transport: %s => %s' % (prefix, klass.__name__)) _protocol_handlers[prefix] = klass class Transport(object): """This class encapsulates methods for retrieving or putting a file from/to a storage location. Most functions have a _multi variant, which allows you to queue up multiple requests. They generally have a dumb base implementation which just iterates over the arguments, but smart Transport implementations can do pipelining. In general implementations should support having a generator or a list as an argument (ie always iterate, never index) """ def __init__(self, base): super(Transport, self).__init__() self.base = base def clone(self, offset=None): """Return a new Transport object, cloned from the current location, using a subdirectory or parent directory. This allows connections to be pooled, rather than a new one needed for each subdir. """ raise NotImplementedError def should_cache(self): """Return True if the data pulled across should be cached locally. """ return False def _pump(self, from_file, to_file): """Most children will need to copy from one file-like object or string to another one. This just gives them something easy to call. """ if isinstance(from_file, basestring): to_file.write(from_file) else: from bzrlib.osutils import pumpfile pumpfile(from_file, to_file) def _get_total(self, multi): """Try to figure out how many entries are in multi, but if not possible, return None. """ try: return len(multi) except TypeError: # We can't tell how many, because relpaths is a generator return None def _update_pb(self, pb, msg, count, total): """Update the progress bar based on the current count and total available, total may be None if it was not possible to determine. """ if pb is None: return if total is None: pb.update(msg, count, count+1) else: pb.update(msg, count, total) def _iterate_over(self, multi, func, pb, msg, expand=True): """Iterate over all entries in multi, passing them to func, and update the progress bar as you go along. :param expand: If True, the entries will be passed to the function by expanding the tuple. If False, it will be passed as a single parameter. """ total = self._get_total(multi) count = 0 for entry in multi: self._update_pb(pb, msg, count, total) if expand: func(*entry) else: func(entry) count += 1 return count def abspath(self, relpath): """Return the full url to the given relative path. This can be supplied with a string or a list XXX: Robert Collins 20051016 - is this really needed in the public interface ? """ raise NotImplementedError def relpath(self, abspath): """Return the local path portion from a given absolute path. This default implementation is not suitable for filesystems with aliasing, such as that given by symlinks, where a path may not start with our base, but still be a relpath once aliasing is resolved. """ if not abspath.startswith(self.base): raise NonRelativePath('path %r is not under base URL %r' % (abspath, self.base)) pl = len(self.base) return abspath[pl:].lstrip('/') def has(self, relpath): """Does the file relpath exist? Note that some transports MAY allow querying on directories, but this is not part of the protocol. """ raise NotImplementedError def has_multi(self, relpaths, pb=None): """Return True/False for each entry in relpaths""" total = self._get_total(relpaths) count = 0 for relpath in relpaths: self._update_pb(pb, 'has', count, total) yield self.has(relpath) count += 1 def has_any(self, relpaths): """Return True if any of the paths exist.""" for relpath in relpaths: if self.has(relpath): return True return False def iter_files_recursive(self): """Iter the relative paths of files in the transports sub-tree. As with other listing functions, only some transports implement this,. you may check via is_listable to determine if it will. """ raise NotImplementedError def get(self, relpath): """Get the file at the given relative path. :param relpath: The relative path to the file """ raise NotImplementedError def get_multi(self, relpaths, pb=None): """Get a list of file-like objects, one for each entry in relpaths. :param relpaths: A list of relative paths. :param pb: An optional ProgressBar for indicating percent done. :return: A list or generator of file-like objects """ # TODO: Consider having this actually buffer the requests, # in the default mode, it probably won't give worse performance, # and all children wouldn't have to implement buffering total = self._get_total(relpaths) count = 0 for relpath in relpaths: self._update_pb(pb, 'get', count, total) yield self.get(relpath) count += 1 def put(self, relpath, f): """Copy the file-like or string object into the location. :param relpath: Location to put the contents, relative to base. :param f: File-like or string object. """ raise NotImplementedError def put_multi(self, files, pb=None): """Put a set of files or strings into the location. :param files: A list of tuples of relpath, file object [(path1, file1), (path2, file2),...] :param pb: An optional ProgressBar for indicating percent done. :return: The number of files copied. """ return self._iterate_over(files, self.put, pb, 'put', expand=True) def mkdir(self, relpath): """Create a directory at the given path.""" raise NotImplementedError def mkdir_multi(self, relpaths, pb=None): """Create a group of directories""" return self._iterate_over(relpaths, self.mkdir, pb, 'mkdir', expand=False) def append(self, relpath, f): """Append the text in the file-like or string object to the supplied location. """ raise NotImplementedError def append_multi(self, files, pb=None): """Append the text in each file-like or string object to the supplied location. :param files: A set of (path, f) entries :param pb: An optional ProgressBar for indicating percent done. """ return self._iterate_over(files, self.append, pb, 'append', expand=True) def copy(self, rel_from, rel_to): """Copy the item at rel_from to the location at rel_to""" raise NotImplementedError def copy_multi(self, relpaths, pb=None): """Copy a bunch of entries. :param relpaths: A list of tuples of the form [(from, to), (from, to),...] """ # This is the non-pipelined implementation, so that # implementors don't have to implement everything. return self._iterate_over(relpaths, self.copy, pb, 'copy', expand=True) def copy_to(self, relpaths, other, pb=None): """Copy a set of entries from self into another Transport. :param relpaths: A list/generator of entries to be copied. TODO: This interface needs to be updated so that the target location can be different from the source location. """ # The dummy implementation just does a simple get + put def copy_entry(path): other.put(path, self.get(path)) return self._iterate_over(relpaths, copy_entry, pb, 'copy_to', expand=False) def move(self, rel_from, rel_to): """Move the item at rel_from to the location at rel_to""" raise NotImplementedError def move_multi(self, relpaths, pb=None): """Move a bunch of entries. :param relpaths: A list of tuples of the form [(from1, to1), (from2, to2),...] """ return self._iterate_over(relpaths, self.move, pb, 'move', expand=True) def move_multi_to(self, relpaths, rel_to): """Move a bunch of entries to a single location. This differs from move_multi in that you give a list of from, and a single destination, rather than multiple destinations. :param relpaths: A list of relative paths [from1, from2, from3, ...] :param rel_to: A directory where each entry should be placed. """ # This is not implemented, because you need to do special tricks to # extract the basename, and add it to rel_to raise NotImplementedError def delete(self, relpath): """Delete the item at relpath""" raise NotImplementedError def delete_multi(self, relpaths, pb=None): """Queue up a bunch of deletes to be done. """ return self._iterate_over(relpaths, self.delete, pb, 'delete', expand=False) def stat(self, relpath): """Return the stat information for a file. WARNING: This may not be implementable for all protocols, so use sparingly. NOTE: This returns an object with fields such as 'st_size'. It MAY or MAY NOT return the literal result of an os.stat() call, so all access should be via named fields. ALSO NOTE: Stats of directories may not be supported on some transports. """ raise NotImplementedError def stat_multi(self, relpaths, pb=None): """Stat multiple files and return the information. """ #TODO: Is it worth making this a generator instead of a # returning a list? stats = [] def gather(path): stats.append(self.stat(path)) count = self._iterate_over(relpaths, gather, pb, 'stat', expand=False) return stats def listable(self): """Return True if this store supports listing.""" raise NotImplementedError def list_dir(self, relpath): """Return a list of all files at the given location. WARNING: many transports do not support this, so trying avoid using it if at all possible. """ raise TransportNotPossible("This transport has not " "implemented list_dir.") def lock_read(self, relpath): """Lock the given file for shared (read) access. WARNING: many transports do not support this, so trying avoid using it :return: A lock object, which should contain an unlock() function. """ raise NotImplementedError def lock_write(self, relpath): """Lock the given file for exclusive (write) access. WARNING: many transports do not support this, so trying avoid using it :return: A lock object, which should contain an unlock() function. """ raise NotImplementedError def get_transport(base): global _protocol_handlers if base is None: base = '.' for proto, klass in _protocol_handlers.iteritems(): if proto is not None and base.startswith(proto): return klass(base) # The default handler is the filesystem handler # which has a lookup of None return _protocol_handlers[None](base) def register_lazy_transport(scheme, module, classname): """Register lazy-loaded transport class. When opening a URL with the given scheme, load the module and then instantiate the particular class. """ def _loader(base): mod = __import__(module, globals(), locals(), [classname]) klass = getattr(mod, classname) return klass(base) register_transport(scheme, _loader) def urlescape(relpath): """Escape relpath to be a valid url.""" # TODO utf8 it first. utf8relpath = relpath.encode('utf8') import urllib return urllib.quote(relpath) # None is the default transport, for things with no url scheme register_lazy_transport(None, 'bzrlib.transport.local', 'LocalTransport') register_lazy_transport('file://', 'bzrlib.transport.local', 'LocalTransport') register_lazy_transport('sftp://', 'bzrlib.transport.sftp', 'SFTPTransport') register_lazy_transport('http://', 'bzrlib.transport.http', 'HttpTransport') register_lazy_transport('https://', 'bzrlib.transport.http', 'HttpTransport') register_lazy_transport('ftp://', 'bzrlib.transport.ftp', 'FtpTransport') register_lazy_transport('aftp://', 'bzrlib.transport.ftp', 'FtpTransport')