Merge branch 'master' into 3198-writable-fuse
[arvados.git] / sdk / python / arvados / collection.py
index 82b97456f7ac1d86a49c80ca125f38db577c28e3..89cbda937c59fbb5064d9c81644b07dba623f806 100644 (file)
@@ -3,15 +3,18 @@ import logging
 import os
 import re
 import errno
+import hashlib
 import time
+import threading
 
 from collections import deque
 from stat import *
 
-from .arvfile import split, FileLikeObjectBase, ArvadosFile, ArvadosFileWriter, ArvadosFileReader, _BlockManager, synchronized, must_be_writable, SYNC_READONLY, SYNC_EXPLICIT, NoopLock
-from keep import *
-from .stream import StreamReader, normalize_stream, locator_block_size
-from .ranges import Range, LocatorAndRange
+from .arvfile import split, _FileLikeObjectBase, ArvadosFile, ArvadosFileWriter, ArvadosFileReader, _BlockManager, synchronized, must_be_writable, NoopLock
+from keep import KeepLocator, KeepClient
+from .stream import StreamReader
+from ._normalize_stream import normalize_stream
+from ._ranges import Range, LocatorAndRange
 from .safeapi import ThreadSafeApiCache
 import config
 import errors
@@ -35,7 +38,8 @@ class CollectionBase(object):
         return self._keep_client
 
     def stripped_manifest(self):
-        """
+        """Get the manifest with locator hints stripped.
+
         Return the manifest for the current collection with all
         non-portable hints (i.e., permission signatures and other
         hints other than size hints) removed from the locators.
@@ -54,7 +58,7 @@ class CollectionBase(object):
         return ''.join(clean)
 
 
-class _WriterFile(FileLikeObjectBase):
+class _WriterFile(_FileLikeObjectBase):
     def __init__(self, coll_writer, name):
         super(_WriterFile, self).__init__(name, 'wb')
         self.dest = coll_writer
@@ -63,16 +67,16 @@ class _WriterFile(FileLikeObjectBase):
         super(_WriterFile, self).close()
         self.dest.finish_current_file()
 
-    @FileLikeObjectBase._before_close
+    @_FileLikeObjectBase._before_close
     def write(self, data):
         self.dest.write(data)
 
-    @FileLikeObjectBase._before_close
+    @_FileLikeObjectBase._before_close
     def writelines(self, seq):
         for data in seq:
             self.write(data)
 
-    @FileLikeObjectBase._before_close
+    @_FileLikeObjectBase._before_close
     def flush(self):
         self.dest.flush_data()
 
@@ -466,13 +470,14 @@ class ResumableCollectionWriter(CollectionWriter):
                 "resumable writer can't accept unsourced data")
         return super(ResumableCollectionWriter, self).write(data)
 
+
 ADD = "add"
 DEL = "del"
 MOD = "mod"
 FILE = "file"
 COLLECTION = "collection"
 
-class SynchronizedCollectionBase(CollectionBase):
+class RichCollectionBase(CollectionBase):
     """Base class for Collections and Subcollections.
 
     Implements the majority of functionality relating to accessing items in the
@@ -483,6 +488,7 @@ class SynchronizedCollectionBase(CollectionBase):
     def __init__(self, parent=None):
         self.parent = parent
         self._modified = True
+        self._callback = None
         self._items = {}
 
     def _my_api(self):
@@ -494,10 +500,7 @@ class SynchronizedCollectionBase(CollectionBase):
     def _my_block_manager(self):
         raise NotImplementedError()
 
-    def _populate(self):
-        raise NotImplementedError()
-
-    def sync_mode(self):
+    def writable(self):
         raise NotImplementedError()
 
     def root_collection(self):
@@ -506,6 +509,9 @@ class SynchronizedCollectionBase(CollectionBase):
     def notify(self, event, collection, name, item):
         raise NotImplementedError()
 
+    def stream_name(self):
+        raise NotImplementedError()
+
     @must_be_writable
     @synchronized
     def find_or_create(self, path, create_type):
@@ -517,28 +523,24 @@ class SynchronizedCollectionBase(CollectionBase):
         the path.
 
         :create_type:
-          One of `arvado.collection.FILE` or
-          `arvado.collection.COLLECTION`.  If the path is not found, and value
+          One of `arvados.collection.FILE` or
+          `arvados.collection.COLLECTION`.  If the path is not found, and value
           of create_type is FILE then create and return a new ArvadosFile for
           the last path component.  If COLLECTION, then create and return a new
           Collection for the last path component.
 
         """
 
-        pathcomponents = path.split("/")
-        if pathcomponents[0] == '.':
-            del pathcomponents[0]
-
-        if pathcomponents and pathcomponents[0]:
+        pathcomponents = path.split("/", 1)
+        if pathcomponents[0]:
             item = self._items.get(pathcomponents[0])
             if len(pathcomponents) == 1:
-                # item must be a file
                 if item is None:
                     # create new file
                     if create_type == COLLECTION:
-                        item = Subcollection(self)
+                        item = Subcollection(self, pathcomponents[0])
                     else:
-                        item = ArvadosFile(self)
+                        item = ArvadosFile(self, pathcomponents[0])
                     self._items[pathcomponents[0]] = item
                     self._modified = True
                     self.notify(ADD, self, pathcomponents[0], item)
@@ -546,15 +548,14 @@ class SynchronizedCollectionBase(CollectionBase):
             else:
                 if item is None:
                     # create new collection
-                    item = Subcollection(self)
+                    item = Subcollection(self, pathcomponents[0])
                     self._items[pathcomponents[0]] = item
                     self._modified = True
                     self.notify(ADD, self, pathcomponents[0], item)
-                del pathcomponents[0]
-                if isinstance(item, SynchronizedCollectionBase):
-                    return item.find_or_create("/".join(pathcomponents), create_type)
+                if isinstance(item, RichCollectionBase):
+                    return item.find_or_create(pathcomponents[1], create_type)
                 else:
-                    raise errors.ArgumentError("Interior path components must be subcollection")
+                    raise IOError(errno.ENOTDIR, "Interior path components must be subcollection")
         else:
             return self
 
@@ -566,25 +567,23 @@ class SynchronizedCollectionBase(CollectionBase):
         found.
 
         """
-        pathcomponents = path.split("/")
-        if pathcomponents[0] == '.':
-            del pathcomponents[0]
+        if not path:
+            raise errors.ArgumentError("Parameter 'path' must not be empty.")
 
-        if pathcomponents and pathcomponents[0]:
-            item = self._items.get(pathcomponents[0])
-            if len(pathcomponents) == 1:
-                # item must be a file
-                return item
-            else:
-                del pathcomponents[0]
-                if isinstance(item, SynchronizedCollectionBase):
-                    return item.find("/".join(pathcomponents))
-                else:
-                    raise errors.ArgumentError("Interior path components must be subcollection")
+        pathcomponents = path.split("/", 1)
+        item = self._items.get(pathcomponents[0])
+        if len(pathcomponents) == 1:
+            return item
         else:
-            return self
+            if isinstance(item, RichCollectionBase):
+                if pathcomponents[1]:
+                    return item.find(pathcomponents[1])
+                else:
+                    return item
+            else:
+                raise IOError(errno.ENOTDIR, "Interior path components must be subcollection")
 
-    def mkdirs(path):
+    def mkdirs(self, path):
         """Recursive subcollection create.
 
         Like `os.mkdirs()`.  Will create intermediate subcollections needed to
@@ -593,7 +592,7 @@ class SynchronizedCollectionBase(CollectionBase):
         """
         return self.find_or_create(path, COLLECTION)
 
-    def open(self, path, mode):
+    def open(self, path, mode="r"):
         """Open a file-like object for access.
 
         :path:
@@ -613,11 +612,11 @@ class SynchronizedCollectionBase(CollectionBase):
         """
         mode = mode.replace("b", "")
         if len(mode) == 0 or mode[0] not in ("r", "w", "a"):
-            raise ArgumentError("Bad mode '%s'" % mode)
+            raise errors.ArgumentError("Bad mode '%s'" % mode)
         create = (mode != "r")
 
-        if create and self.sync_mode() == SYNC_READONLY:
-            raise IOError((errno.EROFS, "Collection is read only"))
+        if create and not self.writable():
+            raise IOError(errno.EROFS, "Collection is read only")
 
         if create:
             arvfile = self.find_or_create(path, FILE)
@@ -625,22 +624,23 @@ class SynchronizedCollectionBase(CollectionBase):
             arvfile = self.find(path)
 
         if arvfile is None:
-            raise IOError((errno.ENOENT, "File not found"))
+            raise IOError(errno.ENOENT, "File not found")
         if not isinstance(arvfile, ArvadosFile):
-            raise IOError((errno.EISDIR, "Path must refer to a file."))
+            raise IOError(errno.EISDIR, "Path must refer to a file.")
 
         if mode[0] == "w":
             arvfile.truncate(0)
 
+        name = os.path.basename(path)
+
         if mode == "r":
-            return ArvadosFileReader(arvfile, path, mode, num_retries=self.num_retries)
+            return ArvadosFileReader(arvfile, mode, num_retries=self.num_retries)
         else:
-            return ArvadosFileWriter(arvfile, path, mode, num_retries=self.num_retries)
+            return ArvadosFileWriter(arvfile, mode, num_retries=self.num_retries)
 
     @synchronized
     def modified(self):
-        """Test if the collection (or any subcollection or file) has been modified
-        since it was created."""
+        """Test if the collection (or any subcollection or file) has been modified."""
         if self._modified:
             return True
         for k,v in self._items.items():
@@ -660,22 +660,18 @@ class SynchronizedCollectionBase(CollectionBase):
         """Iterate over names of files and collections contained in this collection."""
         return iter(self._items.keys())
 
-    @synchronized
-    def iterkeys(self):
-        """Iterate over names of files and collections directly contained in this collection."""
-        return self._items.keys()
-
     @synchronized
     def __getitem__(self, k):
-        """Get a file or collection that is directly contained by this collection.  If
-        you want to search a path, use `find()` instead.
+        """Get a file or collection that is directly contained by this collection.
+
+        If you want to search a path, use `find()` instead.
+
         """
         return self._items[k]
 
     @synchronized
     def __contains__(self, k):
-        """If there is a file or collection a directly contained by this collection
-        with name `k`."""
+        """Test if there is a file or collection a directly contained by this collection."""
         return k in self._items
 
     @synchronized
@@ -708,7 +704,7 @@ class SynchronizedCollectionBase(CollectionBase):
 
     def exists(self, path):
         """Test if there is a file or collection at `path`."""
-        return self.find(path) != None
+        return self.find(path) is not None
 
     @must_be_writable
     @synchronized
@@ -718,63 +714,84 @@ class SynchronizedCollectionBase(CollectionBase):
         :recursive:
           Specify whether to remove non-empty subcollections (True), or raise an error (False).
         """
-        pathcomponents = path.split("/")
-        if pathcomponents[0] == '.':
-            # Remove '.' from the front of the path
-            del pathcomponents[0]
 
-        if len(pathcomponents) > 0:
-            item = self._items.get(pathcomponents[0])
-            if item is None:
-                raise IOError((errno.ENOENT, "File not found"))
-            if len(pathcomponents) == 1:
-                if isinstance(self._items[pathcomponents[0]], SynchronizedCollectionBase) and len(self._items[pathcomponents[0]]) > 0 and not recursive:
-                    raise IOError((errno.ENOTEMPTY, "Subcollection not empty"))
-                deleteditem = self._items[pathcomponents[0]]
-                del self._items[pathcomponents[0]]
-                self._modified = True
-                self.notify(DEL, self, pathcomponents[0], deleteditem)
-            else:
-                del pathcomponents[0]
-                item.remove("/".join(pathcomponents))
+        if not path:
+            raise errors.ArgumentError("Parameter 'path' must not be empty.")
+
+        pathcomponents = path.split("/", 1)
+        item = self._items.get(pathcomponents[0])
+        if item is None:
+            raise IOError(errno.ENOENT, "File not found")
+        if len(pathcomponents) == 1:
+            if isinstance(self._items[pathcomponents[0]], RichCollectionBase) and len(self._items[pathcomponents[0]]) > 0 and not recursive:
+                raise IOError(errno.ENOTEMPTY, "Subcollection not empty")
+            deleteditem = self._items[pathcomponents[0]]
+            del self._items[pathcomponents[0]]
+            self._modified = True
+            self.notify(DEL, self, pathcomponents[0], deleteditem)
         else:
-            raise IOError((errno.ENOENT, "File not found"))
+            item.remove(pathcomponents[1])
 
-    def _cloneinto(self, target):
-        for k,v in self._items.items():
-            target._items[k] = v.clone(target)
+    def _clonefrom(self, source):
+        for k,v in source.items():
+            self._items[k] = v.clone(self, k)
 
     def clone(self):
         raise NotImplementedError()
 
     @must_be_writable
     @synchronized
-    def copy(self, source, target_path, source_collection=None, overwrite=False):
-        """Copy a file or subcollection to a new path in this collection.
+    def add(self, source_obj, target_name, overwrite=False, reparent=False):
+        """Copy or move a file or subcollection to this collection.
 
-        :source:
-          An ArvadosFile, Subcollection, or string with a path to source file or subcollection
+        :source_obj:
+          An ArvadosFile, or Subcollection object
 
-        :target_path:
-          Destination file or path.  If the target path already exists and is a
-          subcollection, the item will be placed inside the subcollection.  If
-          the target path already exists and is a file, this will raise an error
-          unless you specify `overwrite=True`.
-
-        :source_collection:
-          Collection to copy `source_path` from (default `self`)
+        :target_name:
+          Destination item name.  If the target name already exists and is a
+          file, this will raise an error unless you specify `overwrite=True`.
 
         :overwrite:
           Whether to overwrite target file if it already exists.
+
+        :reparent:
+          If True, source_obj will be moved from its parent collection to this collection.
+          If False, source_obj will be copied and the parent collection will be
+          unmodified.
+
         """
+
+        if target_name in self and not overwrite:
+            raise IOError(errno.EEXIST, "File already exists")
+
+        modified_from = None
+        if target_name in self:
+            modified_from = self[target_name]
+
+        # Actually make the move or copy.
+        if reparent:
+            source_obj.reparent(self, target_name)
+            item = source_obj
+        else:
+            item = source_obj.clone(self, target_name)
+
+        self._items[target_name] = item
+        self._modified = True
+
+        if modified_from:
+            self.notify(MOD, self, target_name, (modified_from, item))
+        else:
+            self.notify(ADD, self, target_name, item)
+
+    def _get_src_target(self, source, target_path, source_collection, create_dest):
         if source_collection is None:
             source_collection = self
 
-        # Find the object to copy
+        # Find the object
         if isinstance(source, basestring):
             source_obj = source_collection.find(source)
             if source_obj is None:
-                raise IOError((errno.ENOENT, "File not found"))
+                raise IOError(errno.ENOENT, "File not found")
             sourcecomponents = source.split("/")
         else:
             source_obj = source
@@ -784,41 +801,120 @@ class SynchronizedCollectionBase(CollectionBase):
         targetcomponents = target_path.split("/")
 
         # Determine the name to use.
-        target_name = targetcomponents[-1] if targetcomponents[-1] else (sourcecomponents[-1] if sourcecomponents else None)
+        target_name = targetcomponents[-1] if targetcomponents[-1] else sourcecomponents[-1]
 
         if not target_name:
             raise errors.ArgumentError("Target path is empty and source is an object.  Cannot determine destination filename to use.")
 
-        target_dir = self.find_or_create("/".join(targetcomponents[0:-1]), COLLECTION)
+        if create_dest:
+            target_dir = self.find_or_create("/".join(targetcomponents[0:-1]), COLLECTION)
+        else:
+            if len(targetcomponents) > 1:
+                target_dir = self.find("/".join(targetcomponents[0:-1]))
+            else:
+                target_dir = self
 
-        with target_dir.lock:
-            if target_name in target_dir:
-                if isinstance(target_dir[target_name], SynchronizedCollectionBase) and sourcecomponents:
-                    target_dir = target_dir[target_name]
-                    target_name = sourcecomponents[-1]
-                elif not overwrite:
-                    raise IOError((errno.EEXIST, "File already exists"))
+        if target_dir is None:
+            raise IOError(errno.ENOENT, "Target directory not found.")
 
-            modified_from = None
-            if target_name in target_dir:
-                modified_from = target_dir[target_name]
+        if target_name in target_dir and isinstance(self[target_name], RichCollectionBase) and sourcecomponents:
+            target_dir = target_dir[target_name]
+            target_name = sourcecomponents[-1]
 
-            # Actually make the copy.
-            dup = source_obj.clone(target_dir)
-            target_dir._items[target_name] = dup
-            target_dir._modified = True
+        return (source_obj, target_dir, target_name)
 
-        if modified_from:
-            self.notify(MOD, target_dir, target_name, (modified_from, dup))
-        else:
-            self.notify(ADD, target_dir, target_name, dup)
+    @must_be_writable
+    @synchronized
+    def copy(self, source, target_path, source_collection=None, overwrite=False):
+        """Copy a file or subcollection to a new path in this collection.
 
+        :source:
+          A string with a path to source file or subcollection, or an actual ArvadosFile or Subcollection object.
+
+        :target_path:
+          Destination file or path.  If the target path already exists and is a
+          subcollection, the item will be placed inside the subcollection.  If
+          the target path already exists and is a file, this will raise an error
+          unless you specify `overwrite=True`.
+
+        :source_collection:
+          Collection to copy `source_path` from (default `self`)
+
+        :overwrite:
+          Whether to overwrite target file if it already exists.
+        """
+
+        source_obj, target_dir, target_name = self._get_src_target(source, target_path, source_collection, True)
+        target_dir.add(source_obj, target_name, overwrite, False)
+
+    @must_be_writable
     @synchronized
+    def rename(self, source, target_path, source_collection=None, overwrite=False):
+        """Move a file or subcollection from `source_collection` to a new path in this collection.
+
+        :source:
+          A string with a path to source file or subcollection.
+
+        :target_path:
+          Destination file or path.  If the target path already exists and is a
+          subcollection, the item will be placed inside the subcollection.  If
+          the target path already exists and is a file, this will raise an error
+          unless you specify `overwrite=True`.
+
+        :source_collection:
+          Collection to copy `source_path` from (default `self`)
+
+        :overwrite:
+          Whether to overwrite target file if it already exists.
+        """
+
+        source_obj, target_dir, target_name = self._get_src_target(source, target_path, source_collection, False)
+        if not source_obj.writable():
+            raise IOError(errno.EROFS, "Source collection must be writable.")
+        target_dir.add(source_obj, target_name, overwrite, True)
+
+    def portable_manifest_text(self, stream_name="."):
+        """Get the manifest text for this collection, sub collections and files.
+
+        This method does not flush outstanding blocks to Keep.  It will return
+        a normalized manifest with access tokens stripped.
+
+        :stream_name:
+          Name to use for this stream (directory)
+
+        """
+        return self._get_manifest_text(stream_name, True, True)
+
     def manifest_text(self, stream_name=".", strip=False, normalize=False):
         """Get the manifest text for this collection, sub collections and files.
 
+        This method will flush outstanding blocks to Keep.  By default, it will
+        not normalize an unmodified manifest or strip access tokens.
+
         :stream_name:
-          Name of the stream (directory)
+          Name to use for this stream (directory)
+
+        :strip:
+          If True, remove signing tokens from block locators if present.
+          If False (default), block locators are left unchanged.
+
+        :normalize:
+          If True, always export the manifest text in normalized form
+          even if the Collection is not modified.  If False (default) and the collection
+          is not modified, return the original manifest text even if it is not
+          in normalized form.
+
+        """
+
+        self._my_block_manager().commit_all()
+        return self._get_manifest_text(stream_name, strip, normalize)
+
+    @synchronized
+    def _get_manifest_text(self, stream_name, strip, normalize):
+        """Get the manifest text for this collection, sub collections and files.
+
+        :stream_name:
+          Name to use for this stream (directory)
 
         :strip:
           If True, remove signing tokens from block locators if present.
@@ -832,56 +928,55 @@ class SynchronizedCollectionBase(CollectionBase):
 
         """
 
-        portable_locators = strip
         if self.modified() or self._manifest_text is None or normalize:
-            item  = self
             stream = {}
-            sorted_keys = sorted(item.keys())
-            for filename in [s for s in sorted_keys if isinstance(item[s], ArvadosFile)]:
+            buf = []
+            sorted_keys = sorted(self.keys())
+            for filename in [s for s in sorted_keys if isinstance(self[s], ArvadosFile)]:
                 # Create a stream per file `k`
-                arvfile = item[filename]
+                arvfile = self[filename]
                 filestream = []
                 for segment in arvfile.segments():
                     loc = segment.locator
                     if arvfile.parent._my_block_manager().is_bufferblock(loc):
                         loc = arvfile.parent._my_block_manager().get_bufferblock(loc).locator()
-                    if portable_locators:
+                    if strip:
                         loc = KeepLocator(loc).stripped()
-                    filestream.append(LocatorAndRange(loc, locator_block_size(loc),
+                    filestream.append(LocatorAndRange(loc, KeepLocator(loc).size,
                                          segment.segment_offset, segment.range_size))
                 stream[filename] = filestream
             if stream:
-                buf += ' '.join(normalize_stream(stream_name, stream))
-                buf += "\n"
-            for dirname in [s for s in sorted_keys if isinstance(item[s], SynchronizedCollectionBase)]:
-                buf += item[dirname].manifest_text(stream_name=os.path.join(stream_name, dirname), portable_locators=portable_locators)
-            return buf
+                buf.append(" ".join(normalize_stream(stream_name, stream)) + "\n")
+            for dirname in [s for s in sorted_keys if isinstance(self[s], RichCollectionBase)]:
+                buf.append(self[dirname].manifest_text(stream_name=os.path.join(stream_name, dirname), strip=strip, normalize=True))
+            return "".join(buf)
         else:
-            if portable_locators:
+            if strip:
                 return self.stripped_manifest()
             else:
                 return self._manifest_text
 
     @synchronized
     def diff(self, end_collection, prefix=".", holding_collection=None):
-        """
-        Generate list of add/modify/delete actions which, when given to `apply`, will
-        change `self` to match `end_collection`
+        """Generate list of add/modify/delete actions.
+
+        When given to `apply`, will change `self` to match `end_collection`
+
         """
         changes = []
         if holding_collection is None:
-            holding_collection = Collection(api_client=self._my_api(), keep_client=self._my_keep(), sync=SYNC_EXPLICIT)
+            holding_collection = Collection(api_client=self._my_api(), keep_client=self._my_keep())
         for k in self:
             if k not in end_collection:
-               changes.append((DEL, os.path.join(prefix, k), self[k].clone(holding_collection)))
+               changes.append((DEL, os.path.join(prefix, k), self[k].clone(holding_collection, "")))
         for k in end_collection:
             if k in self:
                 if isinstance(end_collection[k], Subcollection) and isinstance(self[k], Subcollection):
                     changes.extend(self[k].diff(end_collection[k], os.path.join(prefix, k), holding_collection))
                 elif end_collection[k] != self[k]:
-                    changes.append((MOD, os.path.join(prefix, k), self[k].clone(holding_collection), end_collection[k].clone(holding_collection)))
+                    changes.append((MOD, os.path.join(prefix, k), self[k].clone(holding_collection, ""), end_collection[k].clone(holding_collection, "")))
             else:
-                changes.append((ADD, os.path.join(prefix, k), end_collection[k].clone(holding_collection)))
+                changes.append((ADD, os.path.join(prefix, k), end_collection[k].clone(holding_collection, "")))
         return changes
 
     @must_be_writable
@@ -933,14 +1028,32 @@ class SynchronizedCollectionBase(CollectionBase):
 
     def portable_data_hash(self):
         """Get the portable data hash for this collection's manifest."""
-        stripped = self.manifest_text(strip=True)
+        stripped = self.portable_manifest_text()
         return hashlib.md5(stripped).hexdigest() + '+' + str(len(stripped))
 
+    @synchronized
+    def subscribe(self, callback):
+        if self._callback is None:
+            self._callback = callback
+        else:
+            raise errors.ArgumentError("A callback is already set on this collection.")
+
+    @synchronized
+    def unsubscribe(self):
+        if self._callback is not None:
+            self._callback = None
+
+    @synchronized
+    def notify(self, event, collection, name, item):
+        if self._callback:
+            self._callback(event, collection, name, item)
+        self.root_collection().notify(event, collection, name, item)
+
     @synchronized
     def __eq__(self, other):
         if other is self:
             return True
-        if not isinstance(other, SynchronizedCollectionBase):
+        if not isinstance(other, RichCollectionBase):
             return False
         if len(self._items) != len(other):
             return False
@@ -955,11 +1068,15 @@ class SynchronizedCollectionBase(CollectionBase):
         return not self.__eq__(other)
 
 
-class Collection(SynchronizedCollectionBase):
-    """Represents the root of an Arvados Collection, which may be associated with
-    an API server Collection record.
+class Collection(RichCollectionBase):
+    """Represents the root of an Arvados Collection.
 
-    Brief summary of useful methods:
+    This class is threadsafe.  The root collection object, all subcollections
+    and files are protected by a single lock (i.e. each access locks the entire
+    collection).
+
+    Brief summary of
+    useful methods:
 
     :To read an existing file:
       `c.open("myfile", "r")`
@@ -985,18 +1102,17 @@ class Collection(SynchronizedCollectionBase):
     :To merge remote changes into this object:
       `c.update()`
 
-    This class is threadsafe.  The root collection object, all subcollections
-    and files are protected by a single lock (i.e. each access locks the entire
-    collection).
+    Must be associated with an API server Collection record (during
+    initialization, or using `save_new`) to use `save` or `update`
 
     """
 
     def __init__(self, manifest_locator_or_text=None,
-                 parent=None,
-                 apiconfig=None,
                  api_client=None,
                  keep_client=None,
                  num_retries=None,
+                 parent=None,
+                 apiconfig=None,
                  block_manager=None):
         """Collection constructor.
 
@@ -1029,15 +1145,12 @@ class Collection(SynchronizedCollectionBase):
         else:
             self._config = config.settings()
 
-        self.num_retries = num_retries if num_retries is not None else 2
+        self.num_retries = num_retries if num_retries is not None else 0
         self._manifest_locator = None
         self._manifest_text = None
         self._api_response = None
 
-        self._sync = SYNC_EXPLICIT
-        if not self.lock:
-            self.lock = threading.RLock()
-        self.callbacks = []
+        self.lock = threading.RLock()
         self.events = None
 
         if manifest_locator_or_text:
@@ -1051,28 +1164,31 @@ class Collection(SynchronizedCollectionBase):
                 raise errors.ArgumentError(
                     "Argument to CollectionReader must be a manifest or a collection UUID")
 
-            self._populate()
-
+            try:
+                self._populate()
+            except (IOError, errors.SyntaxError) as e:
+                raise errors.ArgumentError("Error processing manifest text: %s", e)
 
     def root_collection(self):
         return self
 
-    def sync_mode(self):
-        return self._sync
+    def stream_name(self):
+        return "."
+
+    def writable(self):
+        return True
 
     @synchronized
     @retry_method
     def update(self, other=None, num_retries=None):
-        """Fetch the latest collection record on the API server and merge it with the
-        current collection contents.
+        """Merge the latest collection on the API server with the current collection."""
 
-        """
         if other is None:
             if self._manifest_locator is None:
                 raise errors.ArgumentError("`other` is None but collection does not have a manifest_locator uuid")
             response = self._my_api().collections().get(uuid=self._manifest_locator).execute(num_retries=num_retries)
-            other = import_manifest(response["manifest_text"])
-        baseline = import_manifest(self._manifest_text)
+            other = CollectionReader(response["manifest_text"])
+        baseline = CollectionReader(self._manifest_text)
         self.apply(baseline.diff(other))
 
     @synchronized
@@ -1088,7 +1204,7 @@ class Collection(SynchronizedCollectionBase):
             if self._api_client is None:
                 self._my_api()
             else:
-                self._keep_client = KeepClient(api=self._api_client)
+                self._keep_client = KeepClient(api_client=self._api_client)
         return self._keep_client
 
     @synchronized
@@ -1147,7 +1263,7 @@ class Collection(SynchronizedCollectionBase):
             error_via_keep = self._populate_from_keep()
         if self._manifest_text is None:
             # Nothing worked!
-            raise arvados.errors.NotFoundError(
+            raise errors.NotFoundError(
                 ("Failed to retrieve collection '{}' " +
                  "from either API server ({}) or Keep ({})."
                  ).format(
@@ -1156,7 +1272,7 @@ class Collection(SynchronizedCollectionBase):
                     error_via_keep))
         # populate
         self._baseline_manifest = self._manifest_text
-        import_manifest(self._manifest_text, self)
+        self._import_manifest(self._manifest_text)
 
 
     def _has_collection_uuid(self):
@@ -1167,20 +1283,36 @@ class Collection(SynchronizedCollectionBase):
 
     def __exit__(self, exc_type, exc_value, traceback):
         """Support scoped auto-commit in a with: block."""
-        if self._sync != SYNC_READONLY and self._has_collection_uuid():
-            self.save()
+        if exc_type is None:
+            if self.writable() and self._has_collection_uuid():
+                self.save()
         if self._block_manager is not None:
             self._block_manager.stop_threads()
 
     @synchronized
-    def clone(self, new_parent=None, new_sync=SYNC_READONLY, new_config=None):
+    def manifest_locator(self):
+        """Get the manifest locator, if any.
+
+        The manifest locator will be set when the collection is loaded from an
+        API server record or the portable data hash of a manifest.
+
+        The manifest locator will be None if the collection is newly created or
+        was created directly from manifest text.  The method `save_new()` will
+        assign a manifest locator.
+
+        """
+        return self._manifest_locator
+
+    @synchronized
+    def clone(self, new_parent=None, new_name=None, readonly=False, new_config=None):
         if new_config is None:
             new_config = self._config
-        newcollection = Collection(parent=new_parent, apiconfig=new_config, sync=SYNC_EXPLICIT)
-        if new_sync == SYNC_READONLY:
-            newcollection.lock = NoopLock()
-        self._cloneinto(newcollection)
-        newcollection._sync = new_sync
+        if readonly:
+            newcollection = CollectionReader(parent=new_parent, apiconfig=new_config)
+        else:
+            newcollection = Collection(parent=new_parent, apiconfig=new_config)
+
+        newcollection._clonefrom(self)
         return newcollection
 
     @synchronized
@@ -1193,30 +1325,57 @@ class Collection(SynchronizedCollectionBase):
         """
         return self._api_response
 
+    def find_or_create(self, path, create_type):
+        """See `RichCollectionBase.find_or_create`"""
+        if path == ".":
+            return self
+        else:
+            return super(Collection, self).find_or_create(path[2:] if path.startswith("./") else path, create_type)
+
+    def find(self, path):
+        """See `RichCollectionBase.find`"""
+        if path == ".":
+            return self
+        else:
+            return super(Collection, self).find(path[2:] if path.startswith("./") else path)
+
+    def remove(self, path, recursive=False):
+        """See `RichCollectionBase.remove`"""
+        if path == ".":
+            raise errors.ArgumentError("Cannot remove '.'")
+        else:
+            return super(Collection, self).remove(path[2:] if path.startswith("./") else path, recursive)
+
     @must_be_writable
     @synchronized
     @retry_method
     def save(self, merge=True, num_retries=None):
-        """Commit pending buffer blocks to Keep, merge with remote record (if
-        update=True), write the manifest to Keep, and update the collection
-        record.
+        """Save collection to an existing collection record.
+
+        Commit pending buffer blocks to Keep, merge with remote record (if
+        merge=True, the default), and update the collection record.  Returns
+        the current manifest text.
 
         Will raise AssertionError if not associated with a collection record on
         the API server.  If you want to save a manifest to Keep only, see
         `save_new()`.
 
-        :update:
+        :merge:
           Update and merge remote changes before saving.  Otherwise, any
           remote changes will be ignored and overwritten.
 
+        :num_retries:
+          Retry count on API calls (if None,  use the collection default)
+
         """
         if self.modified():
             if not self._has_collection_uuid():
                 raise AssertionError("Collection manifest_locator must be a collection uuid.  Use save_new() for new collections.")
+
             self._my_block_manager().commit_all()
+
             if merge:
                 self.update()
-            self._my_keep().put(self.manifest_text(strip=True), num_retries=num_retries)
 
             text = self.manifest_text(strip=False)
             self._api_response = self._my_api().collections().update(
@@ -1227,22 +1386,30 @@ class Collection(SynchronizedCollectionBase):
             self._manifest_text = self._api_response["manifest_text"]
             self.set_unmodified()
 
+        return self._manifest_text
+
 
     @must_be_writable
     @synchronized
     @retry_method
-    def save_new(self, name=None, create_collection_record=True, owner_uuid=None, ensure_unique_name=False, num_retries=None):
-        """Commit pending buffer blocks to Keep, write the manifest to Keep, and create
-        a new collection record (if create_collection_record True).
-
-        After creating a new collection record, this Collection object will be
-        associated with the new record used by `save()`.
+    def save_new(self, name=None,
+                 create_collection_record=True,
+                 owner_uuid=None,
+                 ensure_unique_name=False,
+                 num_retries=None):
+        """Save collection to a new collection record.
+
+        Commit pending buffer blocks to Keep and, when create_collection_record
+        is True (default), create a new collection record.  After creating a
+        new collection record, this Collection object will be associated with
+        the new record used by `save()`.  Returns the current manifest text.
 
         :name:
           The collection name.
 
-        :keep_only:
-          Only save the manifest to keep, do not create a collection record.
+        :create_collection_record:
+           If True, create a collection record on the API server.
+           If False, only commit blocks to Keep and return the manifest text.
 
         :owner_uuid:
           the user, or project uuid that will own this collection.
@@ -1253,14 +1420,17 @@ class Collection(SynchronizedCollectionBase):
           if it conflicts with a collection with the same name and owner.  If
           False, a name conflict will result in an error.
 
+        :num_retries:
+          Retry count on API calls (if None,  use the collection default)
+
         """
         self._my_block_manager().commit_all()
-        self._my_keep().put(self.manifest_text(strip=True), num_retries=num_retries)
         text = self.manifest_text(strip=False)
 
         if create_collection_record:
             if name is None:
                 name = "Collection created %s" % (time.strftime("%Y-%m-%d %H:%M:%S %Z", time.localtime()))
+                ensure_unique_name = True
 
             body = {"manifest_text": text,
                     "name": name}
@@ -1272,21 +1442,10 @@ class Collection(SynchronizedCollectionBase):
 
             self._manifest_locator = self._api_response["uuid"]
 
-        self._manifest_text = text
-        self.set_unmodified()
-
-    @synchronized
-    def subscribe(self, callback):
-        self.callbacks.append(callback)
+            self._manifest_text = text
+            self.set_unmodified()
 
-    @synchronized
-    def unsubscribe(self, callback):
-        self.callbacks.remove(callback)
-
-    @synchronized
-    def notify(self, event, collection, name, item):
-        for c in self.callbacks:
-            c(event, collection, name, item)
+        return text
 
     @synchronized
     def _import_manifest(self, manifest_text):
@@ -1299,10 +1458,6 @@ class Collection(SynchronizedCollectionBase):
         if len(self) > 0:
             raise ArgumentError("Can only import manifest into an empty collection")
 
-        into_collection = self
-        save_sync = into_collection.sync_mode()
-        into_collection._sync = None
-
         STREAM_NAME = 0
         BLOCKS = 1
         SEGMENTS = 2
@@ -1310,9 +1465,9 @@ class Collection(SynchronizedCollectionBase):
         stream_name = None
         state = STREAM_NAME
 
-        for n in re.finditer(r'(\S+)(\s+|$)', manifest_text):
-            tok = n.group(1)
-            sep = n.group(2)
+        for token_and_separator in re.finditer(r'(\S+)(\s+|$)', manifest_text):
+            tok = token_and_separator.group(1)
+            sep = token_and_separator.group(2)
 
             if state == STREAM_NAME:
                 # starting a new stream
@@ -1321,25 +1476,30 @@ class Collection(SynchronizedCollectionBase):
                 segments = []
                 streamoffset = 0L
                 state = BLOCKS
+                self.mkdirs(stream_name)
                 continue
 
             if state == BLOCKS:
-                s = re.match(r'[0-9a-f]{32}\+(\d+)(\+\S+)*', tok)
-                if s:
-                    blocksize = long(s.group(1))
-                    blocks.append(Range(tok, streamoffset, blocksize))
+                block_locator = re.match(r'[0-9a-f]{32}\+(\d+)(\+\S+)*', tok)
+                if block_locator:
+                    blocksize = long(block_locator.group(1))
+                    blocks.append(Range(tok, streamoffset, blocksize, 0))
                     streamoffset += blocksize
                 else:
                     state = SEGMENTS
 
             if state == SEGMENTS:
-                s = re.search(r'^(\d+):(\d+):(\S+)', tok)
-                if s:
-                    pos = long(s.group(1))
-                    size = long(s.group(2))
-                    name = s.group(3).replace('\\040', ' ')
-                    f = into_collection.find_or_create("%s/%s" % (stream_name, name), FILE)
-                    f.add_segment(blocks, pos, size)
+                file_segment = re.search(r'^(\d+):(\d+):(\S+)', tok)
+                if file_segment:
+                    pos = long(file_segment.group(1))
+                    size = long(file_segment.group(2))
+                    name = file_segment.group(3).replace('\\040', ' ')
+                    filepath = os.path.join(stream_name, name)
+                    afile = self.find_or_create(filepath, FILE)
+                    if isinstance(afile, ArvadosFile):
+                        afile.add_segment(blocks, pos, size)
+                    else:
+                        raise errors.SyntaxError("File %s conflicts with stream of the same name.", filepath)
                 else:
                     # error!
                     raise errors.SyntaxError("Invalid manifest format")
@@ -1348,11 +1508,15 @@ class Collection(SynchronizedCollectionBase):
                 stream_name = None
                 state = STREAM_NAME
 
-        into_collection.set_unmodified()
-        into_collection._sync = save_sync
+        self.set_unmodified()
+
+    @synchronized
+    def notify(self, event, collection, name, item):
+        if self._callback:
+            self._callback(event, collection, name, item)
 
 
-class Subcollection(SynchronizedCollectionBase):
+class Subcollection(RichCollectionBase):
     """This is a subdirectory within a collection that doesn't have its own API
     server record.
 
@@ -1360,15 +1524,18 @@ class Subcollection(SynchronizedCollectionBase):
 
     """
 
-    def __init__(self, parent):
+    def __init__(self, parent, name):
         super(Subcollection, self).__init__(parent)
         self.lock = self.root_collection().lock
+        self._manifest_text = None
+        self.name = name
+        self.num_retries = parent.num_retries
 
     def root_collection(self):
         return self.parent.root_collection()
 
-    def sync_mode(self):
-        return self.root_collection().sync_mode()
+    def writable(self):
+        return self.root_collection().writable()
 
     def _my_api(self):
         return self.root_collection()._my_api()
@@ -1379,42 +1546,62 @@ class Subcollection(SynchronizedCollectionBase):
     def _my_block_manager(self):
         return self.root_collection()._my_block_manager()
 
-    def _populate(self):
-        self.root_collection()._populate()
-
-    def notify(self, event, collection, name, item):
-        return self.root_collection().notify(event, collection, name, item)
+    def stream_name(self):
+        return os.path.join(self.parent.stream_name(), self.name)
 
     @synchronized
-    def clone(self, new_parent):
-        c = Subcollection(new_parent)
-        self._cloneinto(c)
+    def clone(self, new_parent, new_name):
+        c = Subcollection(new_parent, new_name)
+        c._clonefrom(self)
         return c
 
 
 class CollectionReader(Collection):
-    """A read-only collection object from an api collection record locator,
-    a portable data hash of a manifest, or raw manifest text.
+    """A read-only collection object.
 
-    See `Collection` constructor for detailed options.
+    Initialize from an api collection record locator, a portable data hash of a
+    manifest, or raw manifest text.  See `Collection` constructor for detailed
+    options.
 
     """
-    def __init__(self, *args, **kwargs):
-        if not args and not kwargs.get("manifest_locator_or_text"):
-            raise errors.ArgumentError("Must provide manifest locator or text to initialize ReadOnlyCollection")
+    def __init__(self, manifest_locator_or_text, *args, **kwargs):
+        self._in_init = True
+        super(CollectionReader, self).__init__(manifest_locator_or_text, *args, **kwargs)
+        self._in_init = False
 
         # Forego any locking since it should never change once initialized.
         self.lock = NoopLock()
 
-        super(ReadOnlyCollection, self).__init__(*args, **kwargs)
+        # Backwards compatability with old CollectionReader
+        # all_streams() and all_files()
+        self._streams = None
+
+    def writable(self):
+        return self._in_init
+
+    def _populate_streams(orig_func):
+        @functools.wraps(orig_func)
+        def populate_streams_wrapper(self, *args, **kwargs):
+            # Defer populating self._streams until needed since it creates a copy of the manifest.
+            if self._streams is None:
+                if self._manifest_text:
+                    self._streams = [sline.split()
+                                     for sline in self._manifest_text.split("\n")
+                                     if sline]
+                else:
+                    self._streams = []
+            return orig_func(self, *args, **kwargs)
+        return populate_streams_wrapper
 
-        self._sync = SYNC_READONLY
+    @_populate_streams
+    def normalize(self):
+        """Normalize the streams returned by `all_streams`.
 
-        self._streams = [sline.split()
-                         for sline in self._manifest_text.split("\n")
-                         if sline]
+        This method is kept for backwards compatability and only affects the
+        behavior of `all_streams()` and `all_files()`
+
+        """
 
-    def normalize(self):
         # Rearrange streams
         streams = {}
         for s in self.all_streams():
@@ -1429,11 +1616,12 @@ class CollectionReader(Collection):
 
         self._streams = [normalize_stream(s, streams[s])
                          for s in sorted(streams)]
-
+    @_populate_streams
     def all_streams(self):
         return [StreamReader(s, self._my_keep(), num_retries=self.num_retries)
                 for s in self._streams]
 
+    @_populate_streams
     def all_files(self):
         for s in self.all_streams():
             for f in s.all_files():