Reexamined robust writing and statistics

git-svn-id: http://svn.savannah.nongnu.org/svn/rdiff-backup/trunk@110 2b77aa54-bcbc-44c9-a7ec-4f6cf2b41109

18 files changed, 736 insertions, 331 deletions

diff --git a/rdiff-backup/rdiff_backup/header.py b/rdiff-backup/rdiff_backup/header.py
index 9ca40d2..00c801f 100644
--- a/rdiff-backup/rdiff_backup/header.py
+++ b/rdiff-backup/rdiff_backup/header.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 #
 # rdiff-backup -- Mirror files while keeping incremental changes
-# Version 0.7.5.1 released May 25, 2002
+# Version 0.7.5.3 released May 25, 2002
 # Copyright (C) 2001, 2002 Ben Escoto <bescoto@stanford.edu>
 #
 # This program is licensed under the GNU General Public License (GPL).
diff --git a/rdiff-backup/rdiff_backup/highlevel.py b/rdiff-backup/rdiff_backup/highlevel.py
index a9e5ce2..bd34746 100644
--- a/rdiff-backup/rdiff_backup/highlevel.py
+++ b/rdiff-backup/rdiff_backup/highlevel.py
@@ -240,6 +240,7 @@ class HLDestinationStruct:
 		"""Apply diffs and finalize, with checkpointing and statistics"""
 		collated = RORPIter.CollateIterators(diffs, cls.initial_dsiter2)
 		finalizer, ITR = cls.get_finalizer(), cls.get_MirrorITR(inc_rpath)
+		Stats.open_dir_stats_file()
 		dsrp = None
 
 		def error_checked():
@@ -262,13 +263,15 @@ class HLDestinationStruct:
 			cls.check_skip_error(finalizer.Finish, dsrp)
 		except: cls.handle_last_error(dsrp, finalizer, ITR)
 		if Globals.preserve_hardlinks: Hardlink.final_writedata()
-		cls.write_statistics(ITR)
+		Stats.close_dir_stats_file()
+		Stats.write_session_statistics(ITR)
 		SaveState.checkpoint_remove()
 
 	def patch_increment_and_finalize(cls, dest_rpath, diffs, inc_rpath):
 		"""Apply diffs, write increment if necessary, and finalize"""
 		collated = RORPIter.CollateIterators(diffs, cls.initial_dsiter2)
 		finalizer, ITR = cls.get_finalizer(), cls.get_ITR(inc_rpath)
+		Stats.open_dir_stats_file()
 		dsrp = None
 
 		def error_checked():
@@ -292,7 +295,8 @@ class HLDestinationStruct:
 			cls.check_skip_error(finalizer.Finish, dsrp)
 		except: cls.handle_last_error(dsrp, finalizer, ITR)
 		if Globals.preserve_hardlinks: Hardlink.final_writedata()
-		cls.write_statistics(ITR)
+		Stats.close_dir_stats_file()
+		Stats.write_session_statistics(ITR)
 		SaveState.checkpoint_remove()
 
 	def check_skip_error(cls, thunk, dsrp):
@@ -323,19 +327,4 @@ class HLDestinationStruct:
 		SaveState.touch_last_file_definitive()
 		raise
 
-	def write_statistics(cls, ITR):
-		"""Write session statistics to file, log"""
-		stat_inc = Inc.get_inc(Globals.rbdir.append("session_statistics"),
-							   Time.curtime, "data")
-		ITR.StartTime = Time.curtime
-		ITR.EndTime = time.time()
-		if Globals.preserve_hardlinks and Hardlink.final_inc:
-			# include hardlink data in size of increments
-			ITR.IncrementFileSize += Hardlink.final_inc.getsize()
-		ITR.write_stats_to_rp(stat_inc)
-		if Globals.print_statistics:
-			message = ITR.get_stats_logstring("Session statistics")
-			Log.log_to_file(message)
-			Globals.client_conn.sys.stdout.write(message)
-
 MakeClass(HLDestinationStruct)
diff --git a/rdiff-backup/rdiff_backup/increment.py b/rdiff-backup/rdiff_backup/increment.py
index 18b137f..2456b28 100644
--- a/rdiff-backup/rdiff_backup/increment.py
+++ b/rdiff-backup/rdiff_backup/increment.py
@@ -22,7 +22,11 @@ class Inc:
 		mirror is the mirrored file from the last backup,
 		incpref is the prefix of the increment file.
 
-		This function basically moves mirror -> incpref.
+		This function basically moves the information about the mirror
+		file to incpref.
+
+		The returned RobustAction when executed should return the name
+		of the incfile, or None if none was created.
 
 		"""
 		if not (new and new.lstat() or mirror.lstat()):
@@ -39,13 +43,15 @@ class Inc:
 		else: return Inc.makesnapshot_action(mirror, incpref)
 
 	def Increment(new, mirror, incpref):
-		Inc.Increment_action(new, mirror, incpref).execute()
+		return Inc.Increment_action(new, mirror, incpref).execute()
 
 	def makemissing_action(incpref):
 		"""Signify that mirror file was missing"""
-		return RobustAction(lambda: None,
-							Inc.get_inc_ext(incpref, "missing").touch,
-							lambda exp: None)
+		def final(init_val):
+			incrp = Inc.get_inc_ext(incpref, "missing")
+			incrp.touch()
+			return incrp
+		return RobustAction(None, final, None)
 		
 	def makesnapshot_action(mirror, incpref):
 		"""Copy mirror to incfile, since new is quite different"""
@@ -62,22 +68,29 @@ class Inc:
 		if (Globals.compression and
 			not Globals.no_compression_regexp.match(mirror.path)):
 			diff = Inc.get_inc_ext(incpref, "diff.gz")
-			return Robust.chain([Rdiff.write_delta_action(new, mirror,
-														  diff, 1),
-								 Robust.copy_attribs_action(mirror, diff)])
+			compress = 1
 		else: 
 			diff = Inc.get_inc_ext(incpref, "diff")
-			return Robust.chain([Rdiff.write_delta_action(new, mirror,
-														  diff, None),
-								 Robust.copy_attribs_action(mirror, diff)])
+			compress = None
+			
+		diff_tf = TempFileManager.new(diff)
+		sig_tf = TempFileManager.new(mirror, None)
+		def init():
+			Rdiff.write_delta(new, mirror, diff_tf, compress, sig_tf)
+			RPath.copy_attribs(mirror, diff_tf)
+			return diff
+		return Robust.make_tf_robustaction(init, (diff_tf, sig_tf),
+										   (diff, None))
 
 	def makedir_action(mirrordir, incpref):
 		"""Make file indicating directory mirrordir has changed"""
 		dirsign = Inc.get_inc_ext(incpref, "dir")
-		def final():
-			dirsign.touch()
-			RPath.copy_attribs(mirrordir, dirsign)
-		return RobustAction(lambda: None, final, dirsign.delete)
+		tf = TempFileManager.new(dirsign)
+		def init():
+			tf.touch()
+			RPath.copy_attribs(mirrordir, tf)
+			return dirsign
+		return Robust.make_tf_robustaction(init, tf, dirsign)
 
 	def get_inc(rp, time, typestr):
 		"""Return increment like rp but with time and typestr suffixes"""
@@ -127,8 +140,15 @@ class IncrementITR(StatsITR):
 	Remember this object needs to be pickable.
 	
 	"""
-	mirror_isdirectory, directory_replacement = None, None
+	# Iff true, mirror file was a directory
+	mirror_isdirectory = None
+	# If set, what the directory on the mirror side will be replaced with
+	directory_replacement = None
+	# True iff there has been some change at this level or lower (used
+	# for marking directories to be flagged)
 	changed = None
+	# Holds the RPath of the created increment file, if any
+	incrp = None
 
 	def __init__(self, inc_rpath):
 		"""Set inc_rpath, an rpath of the base of the tree"""
@@ -184,26 +204,34 @@ class IncrementITR(StatsITR):
 		if not (incpref.lstat() and incpref.isdir()): incpref.mkdir()
 		if diff_rorp and diff_rorp.isreg() and diff_rorp.file:
 			tf = TempFileManager.new(dsrp)
-			RPathStatic.copy_with_attribs(diff_rorp, tf)
-			tf.set_attached_filetype(diff_rorp.get_attached_filetype())
+			def init():
+				RPathStatic.copy_with_attribs(diff_rorp, tf)
+				tf.set_attached_filetype(diff_rorp.get_attached_filetype())
+			def error(exc, ran_init, init_val): tf.delete()
+			RobustAction(init, None, error).execute()
 			self.directory_replacement = tf
 
 	def init_non_dir(self, dsrp, diff_rorp, incpref):
 		"""Process a non directory file (initial pass)"""
 		if not diff_rorp: return # no diff, so no change necessary
 		if diff_rorp.isreg() and (dsrp.isreg() or diff_rorp.isflaglinked()):
-			tf = TempFileManager.new(dsrp)
+			# Write updated mirror to temp file so we can compute
+			# reverse diff locally
+			mirror_tf = TempFileManager.new(dsrp)
 			def init_thunk():
 				if diff_rorp.isflaglinked():
-					Hardlink.link_rp(diff_rorp, tf, dsrp)
+					Hardlink.link_rp(diff_rorp, mirror_tf, dsrp)
 				else: Rdiff.patch_with_attribs_action(dsrp, diff_rorp,
-													  tf).execute()
-				Inc.Increment_action(tf, dsrp, incpref).execute()
-			Robust.make_tf_robustaction(init_thunk, (tf,), (dsrp,)).execute()
-		else:
-			Robust.chain([Inc.Increment_action(diff_rorp, dsrp, incpref),
-						  RORPIter.patchonce_action(None, dsrp, diff_rorp)]
-						 ).execute()
+													  mirror_tf).execute()
+				self.incrp = Inc.Increment_action(mirror_tf, dsrp,
+												  incpref).execute()
+			def final(init_val): mirror_tf.rename(dsrp)
+			def error(exc, ran_init, init_val): mirror_tf.delete()
+			RobustAction(init_thunk, final, error).execute()
+		else: self.incrp = Robust.chain(
+			Inc.Increment_action(diff_rorp, dsrp, incpref),
+			RORPIter.patchonce_action(None, dsrp, diff_rorp)).execute()[0]
+
 		self.changed = 1
 
 	def end_process(self):
@@ -217,19 +245,18 @@ class IncrementITR(StatsITR):
 
 			if self.directory_replacement:
 				tf = self.directory_replacement
-				Inc.Increment(tf, dsrp, incpref)
-				RORPIter.patchonce_action(None, dsrp, tf).execute()
+				self.incrp = Robust.chain(
+					Inc.Increment_action(tf, dsrp, incpref),
+					RORPIter.patchonce_action(None, dsrp, tf)).execute()[0]
 				tf.delete()
 			else:
-				Inc.Increment(diff_rorp, dsrp, incpref)
+				self.incrp = Inc.Increment(diff_rorp, dsrp, incpref)
 				if diff_rorp:
 					RORPIter.patchonce_action(None, dsrp, diff_rorp).execute()
 
-		self.end_stats(diff_rorp, dsrp, Inc._inc_file)
-		if self.incpref.isdir() and (self.mirror_isdirectory or dsrp.isdir()):
-			self.write_stats_to_rp(Inc.get_inc(
-				self.incpref.append("directory_statistics"),
-				Time.curtime, "data"))
+		self.end_stats(diff_rorp, dsrp, self.incrp)
+		if self.mirror_isdirectory or dsrp.isdir():
+			Stats.write_dir_stats_line(self, dsrp.index)
 
 	def branch_process(self, subinstance):
 		"""Update statistics, and the has_changed flag if change in branch"""
@@ -239,6 +266,8 @@ class IncrementITR(StatsITR):
 
 class MirrorITR(StatsITR):
 	"""Like IncrementITR, but only patch mirror directory, don't increment"""
+	# This is always None since no increments will be created
+	incrp = None
 	def __init__(self, inc_rpath):
 		"""Set inc_rpath, an rpath of the base of the inc tree"""
 		self.inc_rpath = inc_rpath
@@ -251,9 +280,6 @@ class MirrorITR(StatsITR):
 			RORPIter.patchonce_action(None, mirror_dsrp, diff_rorp).execute()
 
 		self.incpref = self.inc_rpath.new_index(index)
-		if mirror_dsrp.isdir() and not self.incpref.lstat():
-			self.incpref.mkdir() # holds the statistics files
-
 		self.diff_rorp, self.mirror_dsrp = diff_rorp, mirror_dsrp
 
 	def end_process(self):
@@ -262,11 +288,9 @@ class MirrorITR(StatsITR):
 		except AttributeError: # Some error above prevented these being set
 			return
 		
-		self.end_stats(self.diff_rorp, self.mirror_dsrp)
-		if self.incpref.isdir():
-			self.write_stats_to_rp(Inc.get_inc(
-				self.incpref.append("directory_statistics"),
-				Time.curtime, "data"))
+		self.end_stats(diff_rorp, mirror_dsrp)
+		if mirror_dsrp.isdir():
+			Stats.write_dir_stats_line(self, mirror_dsrp.index)
 
 	def branch_process(self, subinstance):
 		"""Update statistics with subdirectory results"""
diff --git a/rdiff-backup/rdiff_backup/log.py b/rdiff-backup/rdiff_backup/log.py
index 60bf75b..f7e4a89 100644
--- a/rdiff-backup/rdiff_backup/log.py
+++ b/rdiff-backup/rdiff_backup/log.py
@@ -139,6 +139,5 @@ class Logger:
 		logging_func("Exception %s raised of class %s" %
 					 (exc_info[1], exc_info[0]), verbosity)
 		logging_func("".join(traceback.format_tb(exc_info[2])), verbosity+1)
-		
 
 Log = Logger()
diff --git a/rdiff-backup/rdiff_backup/robust.py b/rdiff-backup/rdiff_backup/robust.py
index 3795bd1..74e0d12 100644
--- a/rdiff-backup/rdiff_backup/robust.py
+++ b/rdiff-backup/rdiff_backup/robust.py
@@ -33,69 +33,98 @@ execfile("hardlink.py")
 
 class RobustAction:
 	"""Represents a file operation to be accomplished later"""
-	def __init__(self, init_thunk, final_thunk, error_thunk):
+	def __init__(self, init_thunk, final_func, error_handler):
 		"""RobustAction initializer
 
 		All the thunks are functions whose return value will be
 		ignored.  init_thunk should not make any irreversible changes
-		but prepare for the writing of the important data. final_thunk
+		but prepare for the writing of the important data. final_func
 		should be as short as possible and do the real work.
-		error_thunk is run if there is an error in init_thunk or
-		final_thunk.  Errors in init_thunk should be corrected by
-		error_thunk as if nothing had been run in the first place.
-		The functions take no arguments except for error_thunk, which
-		receives the exception as its only argument.
+		error_handler is run if there is an error in init_thunk or
+		final_func.  Errors in init_thunk should be corrected by
+		error_handler as if nothing had been run in the first place.
+
+		init_thunk takes no arguments.
+
+		final_thunk takes the return value of init_thunk as its
+		argument, and its return value is returned by execute().
+
+		error_handler takes three arguments: the exception, a value
+		which is true just in case self.init_thunk ran correctly, and
+		a value which will be the return value of init_thunk if it ran
+		correctly.
 
 		"""
-		self.init_thunk = init_thunk
-		self.final_thunk = final_thunk
-		self.error_thunk = error_thunk
+		self.init_thunk = init_thunk or self.default_init_thunk
+		self.final_func = final_func or self.default_final_func
+		self.error_handler = error_handler or self.default_error_handler
 
 	def execute(self):
 		"""Actually run the operation"""
+		ran_init_thunk = None
 		try:
-			self.init_thunk()
-			self.final_thunk()
+			init_val = self.init_thunk()
+			ran_init_thunk = 1
+			return self.final_func(init_val)
 		except Exception, exc: # Catch all errors
 			Log.exception()
-			self.error_thunk(exc)
+			if ran_init_thunk: self.error_handler(exc, 1, init_val)
+			else: self.error_handler(exc, None, None)
 			raise exc
 
+	def default_init_thunk(self): return None
+	def default_final_func(self, init_val): return init_val
+	def default_error_handler(self, exc, ran_init, init_val): pass
+
 
 class Robust:
 	"""Contains various file operations made safer using tempfiles"""
-	null_action = RobustAction(lambda: None, lambda: None, lambda e: None)
-	def chain(robust_action_list):
+	null_action = RobustAction(None, None, None)
+	def chain(*robust_action_list):
 		"""Return chain tying together a number of robust actions
 
 		The whole chain will be aborted if some error occurs in
 		initialization stage of any of the component actions.
 
 		"""
-		ras_with_completed_inits = []
+		ras_with_started_inits, init_return_vals = [], []
 		def init():
 			for ra in robust_action_list:
-				ras_with_completed_inits.append(ra)
-				ra.init_thunk()
-		def final():
-			for ra in robust_action_list: ra.final_thunk()
-		def error(exc):
-			for ra in ras_with_completed_inits: ra.error_thunk(exc)
+				ras_with_started_inits.append(ra)
+				init_return_vals.append(ra.init_thunk())
+			return init_return_vals
+		def final(init_return_vals):
+			final_vals = []
+			for ra, init_val in zip(robust_action_list, init_return_vals):
+				final_vals.append(ra.final_func(init_val))
+			return final_vals
+		def error(exc, ran_init, init_val):
+			for ra, init_val in zip(ras_with_started_inits, init_return_vals):
+				ra.error_handler(exc, 1, init_val)
+			for ra in ras_with_started_inits[len(init_return_vals):]:
+				ra.error_handler(exc, None, None)
 		return RobustAction(init, final, error)
 
-	def chain_nested(robust_action_list):
+	def chain_nested(*robust_action_list):
 		"""Like chain but final actions performed in reverse order"""
-		ras_with_completed_inits = []
+		ras_with_started_inits, init_vals = [], []
 		def init():
 			for ra in robust_action_list:
-				ras_with_completed_inits.append(ra)
-				ra.init_thunk()
-		def final():
-			ralist_copy = robust_action_list[:]
-			ralist_copy.reverse()
-			for ra in ralist_copy: ra.final_thunk()
-		def error(exc):
-			for ra in ras_with_completed_inits: ra.error_thunk(exc)
+				ras_with_started_inits.append(ra)
+				init_vals.append(ra.init_thunk())
+			return init_vals
+		def final(init_vals):
+			ras_and_inits = zip(robust_action_list, init_vals)
+			ras_and_inits.reverse()
+			final_vals = []
+			for ra, init_val in ras_and_inits:
+				final_vals.append(ra.final_func(init_val))
+			return final_vals
+		def error(exc, ran_init, init_val):
+			for ra, init_val in zip(ras_with_started_inits, init_return_vals):
+				ra.error_handler(exc, 1, init_val)
+			for ra in ras_with_started_inits[len(init_return_vals):]:
+				ra.error_handler(exc, None, None)
 		return RobustAction(init, final, error)
 
 	def make_tf_robustaction(init_thunk, tempfiles, final_renames = None):
@@ -107,18 +136,19 @@ class Robust:
 		create RobustActions of that type.
 
 		"""
-		assert type(tempfiles) is types.TupleType, tempfiles
-		if final_renames is None: final = lambda: None
-		else:
-			assert len(tempfiles) == len(final_renames)
-			def final(): # rename tempfiles to final positions
-				for i in range(len(tempfiles)):
-					final_name = final_renames[i]
-					if final_name:
-						if final_name.isdir(): # Cannot rename over directory
-							final_name.delete()
-						tempfiles[i].rename(final_name)
-		def error(exc):
+		if isinstance(tempfiles, TempFile): tempfiles = (tempfiles,)
+		if isinstance(final_renames, RPath): final_renames = (final_renames,)
+		if final_renames is None: final_renames = [None] * len(tempfiles)
+		assert len(tempfiles) == len(final_renames)
+
+		def final(init_val): # rename tempfiles to final positions
+			for tempfile, destination in zip(tempfiles, final_renames):
+				if destination:
+					if destination.isdir(): # Cannot rename over directory
+						destination.delete()
+					tempfile.rename(destination)
+			return init_val
+		def error(exc, ran_init, init_val):
 			for tf in tempfiles: tf.delete()
 		return RobustAction(init_thunk, final, error)
 
@@ -130,36 +160,46 @@ class Robust:
 		overwritten).
 		
 		"""
-		tfl = [None] # Need mutable object that init and final can access
+		tfl = [None] # Need some mutable state to hold tf value
 		def init(): 
 			if not (rorpin.isdir() and rpout.isdir()): # already a dir
-				tfl[0] = TempFileManager.new(rpout)
-				if rorpin.isreg(): tfl[0].write_from_fileobj(rorpin.open("rb"))
+				tfl[0] = tf = TempFileManager.new(rpout)
+				if rorpin.isreg(): tf.write_from_fileobj(rorpin.open("rb"))
 				else: RPath.copy(rorpin, tf)
-		def final():
-			if tfl[0] and tfl[0].lstat():
+				return tf
+			else: return None
+		def final(tf):
+			if tf and tf.lstat():
 				if rpout.isdir(): rpout.delete()
-				tfl[0].rename(rpout)
-		return RobustAction(init, final, lambda e: tfl[0] and tfl[0].delete())
+				tf.rename(rpout)
+			return rpout
+		def error(exc, ran_init, init_val):
+			if tfl[0]: tfl[0].delete()
+		return RobustAction(init, final, error)
 
 	def copy_with_attribs_action(rorpin, rpout, compress = None):
 		"""Like copy_action but also copy attributes"""
-		tfl = [None] # Need mutable object that init and final can access
+		tfl = [None] # Need some mutable state for error handler
 		def init(): 
 			if not (rorpin.isdir() and rpout.isdir()): # already a dir
-				tfl[0] = TempFileManager.new(rpout)
+				tfl[0] = tf = TempFileManager.new(rpout)
 				if rorpin.isreg():
-					tfl[0].write_from_fileobj(rorpin.open("rb"), compress)
-				else: RPath.copy(rorpin, tfl[0])
-				if tfl[0].lstat(): # Some files, like sockets, won't be created
-					RPathStatic.copy_attribs(rorpin, tfl[0])
-		def final():
+					tf.write_from_fileobj(rorpin.open("rb"), compress)
+				else: RPath.copy(rorpin, tf)
+				if tf.lstat(): # Some files, like sockets, won't be created
+					RPathStatic.copy_attribs(rorpin, tf)
+				return tf
+			else: return None
+		def final(tf):
 			if rorpin.isdir() and rpout.isdir():
 				RPath.copy_attribs(rorpin, rpout)
-			elif tfl[0] and tfl[0].lstat():
-				if rpout.isdir(): rpout.delete()
-				tfl[0].rename(rpout)
-		return RobustAction(init, final, lambda e: tfl[0] and tfl[0].delete())
+			elif tf and tf.lstat():
+				if rpout.isdir(): rpout.delete() # can't rename over dir
+				tf.rename(rpout)
+			return rpout
+		def error(exc, ran_init, init_val):
+			if tfl[0]: tfl[0].delete()
+		return RobustAction(init, final, error)
 
 	def copy_attribs_action(rorpin, rpout):
 		"""Return action which just copies attributes
@@ -168,14 +208,16 @@ class Robust:
 		normal sequence.
 
 		"""
-		def final(): RPath.copy_attribs(rorpin, rpout)
-		return RobustAction(lambda: None, final, lambda e: None)
+		def final(init_val):
+			RPath.copy_attribs(rorpin, rpout)
+			return rpout
+		return RobustAction(None, final, None)
 
 	def symlink_action(rpath, linktext):
 		"""Return symlink action by moving one file over another"""
 		tf = TempFileManager.new(rpath)
 		def init(): tf.symlink(linktext)
-		return Robust.make_tf_robustaction(init, (tf,), (rpath,))
+		return Robust.make_tf_robustaction(init, tf, rpath)
 
 	def destructive_write_action(rp, s):
 		"""Return action writing string s to rpath rp in robust way
@@ -187,9 +229,9 @@ class Robust:
 		def init():
 			fp = tf.open("wb")
 			fp.write(s)
-			assert not fp.close()
+			fp.close()
 			tf.setdata()
-		return Robust.make_tf_robustaction(init, (tf,), (rp,))
+		return Robust.make_tf_robustaction(init, tf, rp)
 
 	def check_common_error(init_thunk, error_thunk = lambda exc: None):
 		"""Execute init_thunk, if error, run error_thunk on exception
@@ -357,8 +399,8 @@ class SaveState:
 			symtext = apply(os.path.join,
 							('increments',) + last_file_rorp.index)
 			return Robust.symlink_action(cls._last_file_sym, symtext)
-		else: return RobustAction(lambda: None, cls.touch_last_file,
-								  lambda exc: None)
+		else: return RobustAction(None, lambda init_val: cls.touch_last_file(),
+								  None)
 
 	def checkpoint(cls, ITR, finalizer, last_file_rorp, override = None):
 		"""Save states of tree reducer and finalizer during inc backup
@@ -372,9 +414,9 @@ class SaveState:
 		cls._last_checkpoint_time = time.time()
 		Log("Writing checkpoint time %s" % cls._last_checkpoint_time, 7)
 		state_string = cPickle.dumps((ITR, finalizer))
-		Robust.chain([Robust.destructive_write_action(cls._checkpoint_rp,
-													  state_string),
-					  cls.record_last_file_action(last_file_rorp)]).execute()
+		Robust.chain(Robust.destructive_write_action(cls._checkpoint_rp,
+													 state_string),
+					 cls.record_last_file_action(last_file_rorp)).execute()
 
 	def checkpoint_needed(cls):
 		"""Returns true if another checkpoint is called for"""
diff --git a/rdiff-backup/rdiff_backup/rorpiter.py b/rdiff-backup/rdiff_backup/rorpiter.py
index fb30426..1ff0724 100644
--- a/rdiff-backup/rdiff_backup/rorpiter.py
+++ b/rdiff-backup/rdiff_backup/rorpiter.py
@@ -212,13 +212,13 @@ class RORPIter:
 		"""Return action patching basisrp using diff_rorp"""
 		assert diff_rorp, "Missing diff index %s" % basisrp.index
 		if not diff_rorp.lstat():
-			return RobustAction(lambda: None, basisrp.delete, lambda e: None)
+			return RobustAction(None, lambda init_val: basisrp.delete(), None)
 
 		if Globals.preserve_hardlinks and diff_rorp.isflaglinked():
 			if not basisrp: basisrp = base_rp.new_index(diff_rorp.index)
-			return RobustAction(lambda: None,
-								lambda: Hardlink.link_rp(diff_rorp, basisrp),
-								lambda e: None)
+			tf = TempFileManager.new(basisrp)
+			def init(): Hardlink.link_rp(diff_rorp, tf, basisrp)
+			return Robust.make_tf_robustaction(init, tf, basisrp)
 		elif basisrp and basisrp.isreg() and diff_rorp.isreg():
 			assert diff_rorp.get_attached_filetype() == 'diff'
 			return Rdiff.patch_with_attribs_action(basisrp, diff_rorp)
diff --git a/rdiff-backup/rdiff_backup/statistics.py b/rdiff-backup/rdiff_backup/statistics.py
index 8269456..c18f34a 100644
--- a/rdiff-backup/rdiff_backup/statistics.py
+++ b/rdiff-backup/rdiff_backup/statistics.py
@@ -16,13 +16,29 @@ class StatsObj:
 					   'DeletedFiles', 'DeletedFileSize',
 					   'ChangedFiles',
 					   'ChangedSourceSize', 'ChangedMirrorSize',
-					   'IncrementFileSize')
+					   'IncrementFiles', 'IncrementFileSize')
 	stat_time_attrs = ('StartTime', 'EndTime', 'ElapsedTime')
-	stat_attrs = stat_time_attrs + stat_file_attrs
+	stat_attrs = ('Filename',) + stat_time_attrs + stat_file_attrs
+
+	# Below, the second value in each pair is true iff the value
+	# indicates a number of bytes
+	stat_file_pairs = (('SourceFiles', None), ('SourceFileSize', 1),
+					   ('MirrorFiles', None), ('MirrorFileSize', 1),
+					   ('NewFiles', None), ('NewFileSize', 1),
+					   ('DeletedFiles', None), ('DeletedFileSize', 1),
+					   ('ChangedFiles', None),
+					   ('ChangedSourceSize', 1), ('ChangedMirrorSize', 1),
+					   ('IncrementFiles', None), ('IncrementFileSize', 1))
 
 	# Set all stats to None, indicating info not available
 	for attr in stat_attrs: locals()[attr] = None
 
+	# This is used in get_byte_summary_string below
+	byte_abbrev_list = ((1024*1024*1024*1024, "TB"),
+						(1024*1024*1024, "GB"),
+						(1024*1024, "MB"),
+						(1024, "KB"))
+
 	def get_stat(self, attribute):
 		"""Get a statistic"""
 		try: return self.__dict__[attribute]
@@ -34,33 +50,89 @@ class StatsObj:
 		"""Set attribute to given value"""
 		self.__dict__[attr] = value
 
+	def get_stats_line(self, index):
+		"""Return one line abbreviated version of full stats string"""
+		file_attrs = map(lambda attr: str(self.get_stat(attr)),
+						 self.stat_file_attrs)
+		if not index: filename = "."
+		else:
+			# use repr to quote newlines in relative filename, then
+			# take of leading and trailing quote.
+			filename = repr(apply(os.path.join, index))[1:-1]
+		return " ".join([filename,] + file_attrs)
+
+	def set_stats_from_line(self, line):
+		"""Set statistics from given line"""
+		def error(): raise StatsException("Bad line '%s'" % line)
+		if line[-1] == "\n": line = line[:-1]
+		lineparts = line.split(" ")
+		if len(lineparts) < len(stat_file_attrs): error()
+		for attr, val_string in zip(stat_file_attrs,
+									lineparts[-len(stat_file_attrs):]):
+			try: val = long(val_string)
+			except ValueError:
+				try: val = float(val_string)
+				except ValueError: error()
+			self.set_stat(attr, val)
+		return self
+
 	def get_stats_string(self):
-		"""Return string printing out statistics"""
+		"""Return extended string printing out statistics"""
+		return self.get_timestats_string() + self.get_filestats_string()
+
+	def get_timestats_string(self):
+		"""Return portion of statistics string dealing with time"""
 		timelist = []
 		if self.StartTime is not None:
-			timelist.append("StartTime %s (%s)\n" %
+			timelist.append("StartTime %.2f (%s)\n" %
 						(self.StartTime, Time.timetopretty(self.StartTime)))
 		if self.EndTime is not None:
-			timelist.append("EndTime %s (%s)\n" %
+			timelist.append("EndTime %.2f (%s)\n" %
 							(self.EndTime, Time.timetopretty(self.EndTime)))
-		if self.StartTime is not None and self.EndTime is not None:
+		if self.ElapsedTime or (self.StartTime is not None and
+								self.EndTime is not None):
 			if self.ElapsedTime is None:
 				self.ElapsedTime = self.EndTime - self.StartTime
-			timelist.append("ElapsedTime %s (%s)\n" %
+			timelist.append("ElapsedTime %.2f (%s)\n" %
 				   (self.ElapsedTime, Time.inttopretty(self.ElapsedTime)))
+		return "".join(timelist)
+
+	def get_filestats_string(self):
+		"""Return portion of statistics string about files and bytes"""
+		def fileline(stat_file_pair):
+			"""Return zero or one line of the string"""
+			attr, in_bytes = stat_file_pair
+			val = self.get_stat(attr)
+			if val is None: return ""
+			if in_bytes:
+				return "%s %s (%s)\n" % (attr, val,
+										 self.get_byte_summary_string(val))
+			else: return "%s %s\n" % (attr, val)
+
+		return "".join(map(fileline, self.stat_file_pairs))
 
-		filelist = ["%s %s\n" % (attr, self.get_stat(attr))
-					for attr in self.stat_file_attrs
-					if self.get_stat(attr) is not None]
-		return "".join(timelist + filelist)
+	def get_byte_summary_string(self, byte_count):
+		"""Turn byte count into human readable string like "7.23GB" """
+		for abbrev_bytes, abbrev_string in self.byte_abbrev_list:
+			if byte_count >= abbrev_bytes:
+				# Now get 3 significant figures
+				abbrev_count = float(byte_count)/abbrev_bytes
+				if abbrev_count >= 100: precision = 0
+				elif abbrev_count >= 10: precision = 1
+				else: precision = 2
+				return "%%.%df %s" % (precision, abbrev_string) \
+					   % (abbrev_count,)
+		byte_count = round(byte_count)
+		if byte_count == 1: return "1 byte"
+		else: return "%d bytes" % (byte_count,)
 
 	def get_stats_logstring(self, title):
 		"""Like get_stats_string, but add header and footer"""
-		header = "-------------[ %s ]-------------" % title
+		header = "--------------[ %s ]--------------" % title
 		footer = "-" * len(header)
 		return "%s\n%s%s\n" % (header, self.get_stats_string(), footer)
 
-	def init_stats_from_string(self, s):
+	def set_stats_from_string(self, s):
 		"""Initialize attributes from string, return self for convenience"""
 		def error(line): raise StatsException("Bad line '%s'" % line)
 
@@ -91,7 +163,7 @@ class StatsObj:
 	def read_stats_from_rp(self, rp):
 		"""Set statistics from rpath, return self for convenience"""
 		fp = rp.open("r")
-		self.init_stats_from_string(fp.read())
+		self.set_stats_from_string(fp.read())
 		fp.close()
 		return self
 
@@ -162,22 +234,96 @@ class StatsITR(IterTreeReducer, StatsObj):
 					self.ChangedFiles += 1
 					self.ChangedSourceSize += mirror_dsrp.getsize()
 					self.ChangedMirrorSize += self.mirror_base_size
-					self.IncrementFileSize += inc_rp and inc_rp.getsize() or 0
+					if inc_rp:
+						self.IncrementFiles += 1
+						self.IncrementFileSize += inc_rp.getsize()
 			else: # new file was created
 				self.NewFiles += 1
 				self.NewFileSize += mirror_dsrp.getsize()
-				self.IncrementFileSize += inc_rp and inc_rp.getsize() or 0
+				if inc_rp:
+					self.IncrementFiles += 1
+					self.IncrementFileSize += inc_rp.getsize()
 		else:
 			if self.mirror_base_exists: # file was deleted from mirror
 				self.MirrorFiles += 1
 				self.MirrorFileSize += self.mirror_base_size
 				self.DeletedFiles += 1
 				self.DeletedFileSize += self.mirror_base_size
-				self.IncrementFileSize += inc_rp and inc_rp.getsize() or 0
-
+				if inc_rp:
+					self.IncrementFiles += 1
+					self.IncrementFileSize += inc_rp.getsize()
 
 	def add_file_stats(self, subinstance):
 		"""Add all file statistics from subinstance to current totals"""
 		for attr in self.stat_file_attrs:
 			self.set_stat(attr,
 						  self.get_stat(attr) + subinstance.get_stat(attr))
+
+
+class Stats:
+	"""Misc statistics methods, pertaining to dir and session stat files"""
+	# This is the RPath of the directory statistics file, and the
+	# associated open file.  It will hold a line of statistics for
+	# each directory that is backed up.
+	_dir_stats_rp = None
+	_dir_stats_fp = None
+
+	# This goes at the beginning of the directory statistics file and
+	# explains the format.
+	_dir_stats_header = """# rdiff-backup directory statistics file
+#
+# Each line is in the following format:
+# RelativeDirName %s
+""" % " ".join(StatsObj.stat_file_attrs)
+
+	def open_dir_stats_file(cls):
+		"""Open directory statistics file, write header"""
+		assert not cls._dir_stats_fp, "Directory file already open"
+
+		if Globals.compression: suffix = "data.gz"
+		else: suffix = "data"
+		cls._dir_stats_rp = Inc.get_inc(Globals.rbdir.append(
+			"directory_statistics"), Time.curtime, suffix)
+
+		if cls._dir_stats_rp.lstat():
+			Log("Warning, statistics file %s already exists, appending", 2)
+			cls._dir_stats_fp = cls._dir_stats_rp.open("ab",
+													   Globals.compression)
+		else: cls._dir_stats_fp = \
+			  cls._dir_stats_rp.open("wb", Globals.compression)
+		cls._dir_stats_fp.write(cls._dir_stats_header)
+
+	def write_dir_stats_line(cls, statobj, index):
+		"""Write info from statobj about rpath to statistics file"""
+		cls._dir_stats_fp.write(statobj.get_stats_line(index) +"\n")
+
+	def close_dir_stats_file(cls):
+		"""Close directory statistics file if its open"""
+		if cls._dir_stats_fp:
+			cls._dir_stats_fp.close()
+			cls._dir_stats_fp = None
+
+	def write_session_statistics(cls, statobj):
+		"""Write session statistics into file, log"""
+		stat_inc = Inc.get_inc(Globals.rbdir.append("session_statistics"),
+							   Time.curtime, "data")
+		statobj.StartTime = Time.curtime
+		statobj.EndTime = time.time()
+
+		# include hardlink data and dir stats in size of increments
+		if Globals.preserve_hardlinks and Hardlink.final_inc:
+			# include hardlink data in size of increments
+			statobj.IncrementFiles += 1
+			statobj.IncrementFileSize += Hardlink.final_inc.getsize()
+		if cls._dir_stats_rp and cls._dir_stats_rp.lstat():
+			statobj.IncrementFiles += 1
+			statobj.IncrementFileSize += cls._dir_stats_rp.getsize()
+
+		statobj.write_stats_to_rp(stat_inc)
+		if Globals.print_statistics:
+			message = statobj.get_stats_logstring("Session statistics")
+			Log.log_to_file(message)
+			Globals.client_conn.sys.stdout.write(message)
+
+MakeClass(Stats)
+
diff --git a/rdiff-backup/src/globals.py b/rdiff-backup/src/globals.py
index 2a042a8..d4c9471 100644
--- a/rdiff-backup/src/globals.py
+++ b/rdiff-backup/src/globals.py
@@ -8,7 +8,7 @@ import re, os
 class Globals:
 
 	# The current version of rdiff-backup
-	version = "0.7.5.1"
+	version = "0.7.5.3"
 	
 	# If this is set, use this value in seconds as the current time
 	# instead of reading it from the clock.
diff --git a/rdiff-backup/src/header.py b/rdiff-backup/src/header.py
index 9ca40d2..00c801f 100644
--- a/rdiff-backup/src/header.py
+++ b/rdiff-backup/src/header.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 #
 # rdiff-backup -- Mirror files while keeping incremental changes
-# Version 0.7.5.1 released May 25, 2002
+# Version 0.7.5.3 released May 25, 2002
 # Copyright (C) 2001, 2002 Ben Escoto <bescoto@stanford.edu>
 #
 # This program is licensed under the GNU General Public License (GPL).
diff --git a/rdiff-backup/src/highlevel.py b/rdiff-backup/src/highlevel.py
index a9e5ce2..bd34746 100644
--- a/rdiff-backup/src/highlevel.py
+++ b/rdiff-backup/src/highlevel.py
@@ -240,6 +240,7 @@ class HLDestinationStruct:
 		"""Apply diffs and finalize, with checkpointing and statistics"""
 		collated = RORPIter.CollateIterators(diffs, cls.initial_dsiter2)
 		finalizer, ITR = cls.get_finalizer(), cls.get_MirrorITR(inc_rpath)
+		Stats.open_dir_stats_file()
 		dsrp = None
 
 		def error_checked():
@@ -262,13 +263,15 @@ class HLDestinationStruct:
 			cls.check_skip_error(finalizer.Finish, dsrp)
 		except: cls.handle_last_error(dsrp, finalizer, ITR)
 		if Globals.preserve_hardlinks: Hardlink.final_writedata()
-		cls.write_statistics(ITR)
+		Stats.close_dir_stats_file()
+		Stats.write_session_statistics(ITR)
 		SaveState.checkpoint_remove()
 
 	def patch_increment_and_finalize(cls, dest_rpath, diffs, inc_rpath):
 		"""Apply diffs, write increment if necessary, and finalize"""
 		collated = RORPIter.CollateIterators(diffs, cls.initial_dsiter2)
 		finalizer, ITR = cls.get_finalizer(), cls.get_ITR(inc_rpath)
+		Stats.open_dir_stats_file()
 		dsrp = None
 
 		def error_checked():
@@ -292,7 +295,8 @@ class HLDestinationStruct:
 			cls.check_skip_error(finalizer.Finish, dsrp)
 		except: cls.handle_last_error(dsrp, finalizer, ITR)
 		if Globals.preserve_hardlinks: Hardlink.final_writedata()
-		cls.write_statistics(ITR)
+		Stats.close_dir_stats_file()
+		Stats.write_session_statistics(ITR)
 		SaveState.checkpoint_remove()
 
 	def check_skip_error(cls, thunk, dsrp):
@@ -323,19 +327,4 @@ class HLDestinationStruct:
 		SaveState.touch_last_file_definitive()
 		raise
 
-	def write_statistics(cls, ITR):
-		"""Write session statistics to file, log"""
-		stat_inc = Inc.get_inc(Globals.rbdir.append("session_statistics"),
-							   Time.curtime, "data")
-		ITR.StartTime = Time.curtime
-		ITR.EndTime = time.time()
-		if Globals.preserve_hardlinks and Hardlink.final_inc:
-			# include hardlink data in size of increments
-			ITR.IncrementFileSize += Hardlink.final_inc.getsize()
-		ITR.write_stats_to_rp(stat_inc)
-		if Globals.print_statistics:
-			message = ITR.get_stats_logstring("Session statistics")
-			Log.log_to_file(message)
-			Globals.client_conn.sys.stdout.write(message)
-
 MakeClass(HLDestinationStruct)
diff --git a/rdiff-backup/src/increment.py b/rdiff-backup/src/increment.py
index 18b137f..2456b28 100644
--- a/rdiff-backup/src/increment.py
+++ b/rdiff-backup/src/increment.py
@@ -22,7 +22,11 @@ class Inc:
 		mirror is the mirrored file from the last backup,
 		incpref is the prefix of the increment file.
 
-		This function basically moves mirror -> incpref.
+		This function basically moves the information about the mirror
+		file to incpref.
+
+		The returned RobustAction when executed should return the name
+		of the incfile, or None if none was created.
 
 		"""
 		if not (new and new.lstat() or mirror.lstat()):
@@ -39,13 +43,15 @@ class Inc:
 		else: return Inc.makesnapshot_action(mirror, incpref)
 
 	def Increment(new, mirror, incpref):
-		Inc.Increment_action(new, mirror, incpref).execute()
+		return Inc.Increment_action(new, mirror, incpref).execute()
 
 	def makemissing_action(incpref):
 		"""Signify that mirror file was missing"""
-		return RobustAction(lambda: None,
-							Inc.get_inc_ext(incpref, "missing").touch,
-							lambda exp: None)
+		def final(init_val):
+			incrp = Inc.get_inc_ext(incpref, "missing")
+			incrp.touch()
+			return incrp
+		return RobustAction(None, final, None)
 		
 	def makesnapshot_action(mirror, incpref):
 		"""Copy mirror to incfile, since new is quite different"""
@@ -62,22 +68,29 @@ class Inc:
 		if (Globals.compression and
 			not Globals.no_compression_regexp.match(mirror.path)):
 			diff = Inc.get_inc_ext(incpref, "diff.gz")
-			return Robust.chain([Rdiff.write_delta_action(new, mirror,
-														  diff, 1),
-								 Robust.copy_attribs_action(mirror, diff)])
+			compress = 1
 		else: 
 			diff = Inc.get_inc_ext(incpref, "diff")
-			return Robust.chain([Rdiff.write_delta_action(new, mirror,
-														  diff, None),
-								 Robust.copy_attribs_action(mirror, diff)])
+			compress = None
+			
+		diff_tf = TempFileManager.new(diff)
+		sig_tf = TempFileManager.new(mirror, None)
+		def init():
+			Rdiff.write_delta(new, mirror, diff_tf, compress, sig_tf)
+			RPath.copy_attribs(mirror, diff_tf)
+			return diff
+		return Robust.make_tf_robustaction(init, (diff_tf, sig_tf),
+										   (diff, None))
 
 	def makedir_action(mirrordir, incpref):
 		"""Make file indicating directory mirrordir has changed"""
 		dirsign = Inc.get_inc_ext(incpref, "dir")
-		def final():
-			dirsign.touch()
-			RPath.copy_attribs(mirrordir, dirsign)
-		return RobustAction(lambda: None, final, dirsign.delete)
+		tf = TempFileManager.new(dirsign)
+		def init():
+			tf.touch()
+			RPath.copy_attribs(mirrordir, tf)
+			return dirsign
+		return Robust.make_tf_robustaction(init, tf, dirsign)
 
 	def get_inc(rp, time, typestr):
 		"""Return increment like rp but with time and typestr suffixes"""
@@ -127,8 +140,15 @@ class IncrementITR(StatsITR):
 	Remember this object needs to be pickable.
 	
 	"""
-	mirror_isdirectory, directory_replacement = None, None
+	# Iff true, mirror file was a directory
+	mirror_isdirectory = None
+	# If set, what the directory on the mirror side will be replaced with
+	directory_replacement = None
+	# True iff there has been some change at this level or lower (used
+	# for marking directories to be flagged)
 	changed = None
+	# Holds the RPath of the created increment file, if any
+	incrp = None
 
 	def __init__(self, inc_rpath):
 		"""Set inc_rpath, an rpath of the base of the tree"""
@@ -184,26 +204,34 @@ class IncrementITR(StatsITR):
 		if not (incpref.lstat() and incpref.isdir()): incpref.mkdir()
 		if diff_rorp and diff_rorp.isreg() and diff_rorp.file:
 			tf = TempFileManager.new(dsrp)
-			RPathStatic.copy_with_attribs(diff_rorp, tf)
-			tf.set_attached_filetype(diff_rorp.get_attached_filetype())
+			def init():
+				RPathStatic.copy_with_attribs(diff_rorp, tf)
+				tf.set_attached_filetype(diff_rorp.get_attached_filetype())
+			def error(exc, ran_init, init_val): tf.delete()
+			RobustAction(init, None, error).execute()
 			self.directory_replacement = tf
 
 	def init_non_dir(self, dsrp, diff_rorp, incpref):
 		"""Process a non directory file (initial pass)"""
 		if not diff_rorp: return # no diff, so no change necessary
 		if diff_rorp.isreg() and (dsrp.isreg() or diff_rorp.isflaglinked()):
-			tf = TempFileManager.new(dsrp)
+			# Write updated mirror to temp file so we can compute
+			# reverse diff locally
+			mirror_tf = TempFileManager.new(dsrp)
 			def init_thunk():
 				if diff_rorp.isflaglinked():
-					Hardlink.link_rp(diff_rorp, tf, dsrp)
+					Hardlink.link_rp(diff_rorp, mirror_tf, dsrp)
 				else: Rdiff.patch_with_attribs_action(dsrp, diff_rorp,
-													  tf).execute()
-				Inc.Increment_action(tf, dsrp, incpref).execute()
-			Robust.make_tf_robustaction(init_thunk, (tf,), (dsrp,)).execute()
-		else:
-			Robust.chain([Inc.Increment_action(diff_rorp, dsrp, incpref),
-						  RORPIter.patchonce_action(None, dsrp, diff_rorp)]
-						 ).execute()
+													  mirror_tf).execute()
+				self.incrp = Inc.Increment_action(mirror_tf, dsrp,
+												  incpref).execute()
+			def final(init_val): mirror_tf.rename(dsrp)
+			def error(exc, ran_init, init_val): mirror_tf.delete()
+			RobustAction(init_thunk, final, error).execute()
+		else: self.incrp = Robust.chain(
+			Inc.Increment_action(diff_rorp, dsrp, incpref),
+			RORPIter.patchonce_action(None, dsrp, diff_rorp)).execute()[0]
+
 		self.changed = 1
 
 	def end_process(self):
@@ -217,19 +245,18 @@ class IncrementITR(StatsITR):
 
 			if self.directory_replacement:
 				tf = self.directory_replacement
-				Inc.Increment(tf, dsrp, incpref)
-				RORPIter.patchonce_action(None, dsrp, tf).execute()
+				self.incrp = Robust.chain(
+					Inc.Increment_action(tf, dsrp, incpref),
+					RORPIter.patchonce_action(None, dsrp, tf)).execute()[0]
 				tf.delete()
 			else:
-				Inc.Increment(diff_rorp, dsrp, incpref)
+				self.incrp = Inc.Increment(diff_rorp, dsrp, incpref)
 				if diff_rorp:
 					RORPIter.patchonce_action(None, dsrp, diff_rorp).execute()
 
-		self.end_stats(diff_rorp, dsrp, Inc._inc_file)
-		if self.incpref.isdir() and (self.mirror_isdirectory or dsrp.isdir()):
-			self.write_stats_to_rp(Inc.get_inc(
-				self.incpref.append("directory_statistics"),
-				Time.curtime, "data"))
+		self.end_stats(diff_rorp, dsrp, self.incrp)
+		if self.mirror_isdirectory or dsrp.isdir():
+			Stats.write_dir_stats_line(self, dsrp.index)
 
 	def branch_process(self, subinstance):
 		"""Update statistics, and the has_changed flag if change in branch"""
@@ -239,6 +266,8 @@ class IncrementITR(StatsITR):
 
 class MirrorITR(StatsITR):
 	"""Like IncrementITR, but only patch mirror directory, don't increment"""
+	# This is always None since no increments will be created
+	incrp = None
 	def __init__(self, inc_rpath):
 		"""Set inc_rpath, an rpath of the base of the inc tree"""
 		self.inc_rpath = inc_rpath
@@ -251,9 +280,6 @@ class MirrorITR(StatsITR):
 			RORPIter.patchonce_action(None, mirror_dsrp, diff_rorp).execute()
 
 		self.incpref = self.inc_rpath.new_index(index)
-		if mirror_dsrp.isdir() and not self.incpref.lstat():
-			self.incpref.mkdir() # holds the statistics files
-
 		self.diff_rorp, self.mirror_dsrp = diff_rorp, mirror_dsrp
 
 	def end_process(self):
@@ -262,11 +288,9 @@ class MirrorITR(StatsITR):
 		except AttributeError: # Some error above prevented these being set
 			return
 		
-		self.end_stats(self.diff_rorp, self.mirror_dsrp)
-		if self.incpref.isdir():
-			self.write_stats_to_rp(Inc.get_inc(
-				self.incpref.append("directory_statistics"),
-				Time.curtime, "data"))
+		self.end_stats(diff_rorp, mirror_dsrp)
+		if mirror_dsrp.isdir():
+			Stats.write_dir_stats_line(self, mirror_dsrp.index)
 
 	def branch_process(self, subinstance):
 		"""Update statistics with subdirectory results"""
diff --git a/rdiff-backup/src/log.py b/rdiff-backup/src/log.py
index 60bf75b..f7e4a89 100644
--- a/rdiff-backup/src/log.py
+++ b/rdiff-backup/src/log.py
@@ -139,6 +139,5 @@ class Logger:
 		logging_func("Exception %s raised of class %s" %
 					 (exc_info[1], exc_info[0]), verbosity)
 		logging_func("".join(traceback.format_tb(exc_info[2])), verbosity+1)
-		
 
 Log = Logger()
diff --git a/rdiff-backup/src/main.py b/rdiff-backup/src/main.py
index c222fdc..6b1db51 100755
--- a/rdiff-backup/src/main.py
+++ b/rdiff-backup/src/main.py
@@ -146,7 +146,8 @@ class Main:
 					   self.action == "remove-older-than"):
 			self.commandline_error("Only use one argument, "
 								   "the root of the backup directory")
-		if l > 2: self.commandline_error("Too many arguments given")
+		if l > 2 and self.action != "calculate-average":
+			self.commandline_error("Too many arguments given")
 
 	def commandline_error(self, message):
 		sys.stderr.write("Error: %s\n" % message)
diff --git a/rdiff-backup/src/rdiff.py b/rdiff-backup/src/rdiff.py
index 3b5ba95..e4552ce 100644
--- a/rdiff-backup/src/rdiff.py
+++ b/rdiff-backup/src/rdiff.py
@@ -24,11 +24,11 @@ class Rdiff:
 		"""Like get_delta but signature is in a file object"""
 		sig_tf = TempFileManager.new(rp_new, None)
 		sig_tf.write_from_fileobj(sig_fileobj)
-		rdiff_popen_obj = Rdiff.get_delta(sig_tf, rp_new)
+		rdiff_popen_obj = Rdiff.get_delta_sigrp(sig_tf, rp_new)
 		rdiff_popen_obj.set_thunk(sig_tf.delete)
 		return rdiff_popen_obj
 
-	def get_delta(rp_signature, rp_new):
+	def get_delta_sigrp(rp_signature, rp_new):
 		"""Take signature rp and new rp, return delta file object"""
 		assert rp_signature.conn is rp_new.conn
 		Log("Getting delta of %s with signature %s" %
@@ -45,18 +45,18 @@ class Rdiff:
 		"""
 		sig_tf = TempFileManager.new(new, None)
 		delta_tf = TempFileManager.new(delta)
-		def init():
-			Log("Writing delta %s from %s -> %s" %
-				(basis.path, new.path, delta.path), 7)
-			sig_tf.write_from_fileobj(Rdiff.get_signature(basis))
-			delta_tf.write_from_fileobj(Rdiff.get_delta(sig_tf, new), compress)
-			sig_tf.delete()
+		def init(): Rdiff.write_delta(basis, new, delta_tf, compress, sig_tf)
 		return Robust.make_tf_robustaction(init, (sig_tf, delta_tf),
 										   (None, delta))
 
-	def write_delta(basis, new, delta, compress = None):
+	def write_delta(basis, new, delta, compress = None, sig_tf = None):
 		"""Write rdiff delta which brings basis to new"""
-		Rdiff.write_delta_action(basis, new, delta, compress).execute()
+		Log("Writing delta %s from %s -> %s" %
+			(basis.path, new.path, delta.path), 7)
+		if not sig_tf: sig_tf = TempFileManager.new(new, None)
+		sig_tf.write_from_fileobj(Rdiff.get_signature(basis))
+		delta.write_from_fileobj(Rdiff.get_delta_sigrp(sig_tf, new), compress)
+		sig_tf.delete()
 
 	def patch_action(rp_basis, rp_delta, rp_out = None,
 					 out_tf = None, delta_compressed = None):
@@ -106,18 +106,20 @@ class Rdiff:
 		if not rp_out: rp_out = rp_basis
 		delta_tf = TempFileManager.new(rp_out, None)
 		def init(): delta_tf.write_from_fileobj(delta_fileobj)
-		return Robust.chain_nested([RobustAction(init, delta_tf.delete,
-												 lambda exc: delta_tf.delete),
-									Rdiff.patch_action(rp_basis, delta_tf,
-													   rp_out, out_tf)])
+		def final(init_val): delta_tf.delete()
+		def error(exc, ran_init, init_val): delta_tf.delete()
+		write_delta_action = RobustAction(init, final, error)
+		return Robust.chain(write_delta_action,
+							Rdiff.patch_action(rp_basis, delta_tf,
+											   rp_out, out_tf))
 
 	def patch_with_attribs_action(rp_basis, rp_delta, rp_out = None):
 		"""Like patch_action, but also transfers attributs from rp_delta"""
 		if not rp_out: rp_out = rp_basis
 		tf = TempFileManager.new(rp_out)
 		return Robust.chain_nested(
-			[Rdiff.patch_action(rp_basis, rp_delta, rp_out, tf),
-			 Robust.copy_attribs_action(rp_delta, tf)])
+			Rdiff.patch_action(rp_basis, rp_delta, rp_out, tf),
+			Robust.copy_attribs_action(rp_delta, tf))
 
 	def copy_action(rpin, rpout):
 		"""Use rdiff to copy rpin to rpout, conserving bandwidth"""
diff --git a/rdiff-backup/src/robust.py b/rdiff-backup/src/robust.py
index 3795bd1..74e0d12 100644
--- a/rdiff-backup/src/robust.py
+++ b/rdiff-backup/src/robust.py
@@ -33,69 +33,98 @@ execfile("hardlink.py")
 
 class RobustAction:
 	"""Represents a file operation to be accomplished later"""
-	def __init__(self, init_thunk, final_thunk, error_thunk):
+	def __init__(self, init_thunk, final_func, error_handler):
 		"""RobustAction initializer
 
 		All the thunks are functions whose return value will be
 		ignored.  init_thunk should not make any irreversible changes
-		but prepare for the writing of the important data. final_thunk
+		but prepare for the writing of the important data. final_func
 		should be as short as possible and do the real work.
-		error_thunk is run if there is an error in init_thunk or
-		final_thunk.  Errors in init_thunk should be corrected by
-		error_thunk as if nothing had been run in the first place.
-		The functions take no arguments except for error_thunk, which
-		receives the exception as its only argument.
+		error_handler is run if there is an error in init_thunk or
+		final_func.  Errors in init_thunk should be corrected by
+		error_handler as if nothing had been run in the first place.
+
+		init_thunk takes no arguments.
+
+		final_thunk takes the return value of init_thunk as its
+		argument, and its return value is returned by execute().
+
+		error_handler takes three arguments: the exception, a value
+		which is true just in case self.init_thunk ran correctly, and
+		a value which will be the return value of init_thunk if it ran
+		correctly.
 
 		"""
-		self.init_thunk = init_thunk
-		self.final_thunk = final_thunk
-		self.error_thunk = error_thunk
+		self.init_thunk = init_thunk or self.default_init_thunk
+		self.final_func = final_func or self.default_final_func
+		self.error_handler = error_handler or self.default_error_handler
 
 	def execute(self):
 		"""Actually run the operation"""
+		ran_init_thunk = None
 		try:
-			self.init_thunk()
-			self.final_thunk()
+			init_val = self.init_thunk()
+			ran_init_thunk = 1
+			return self.final_func(init_val)
 		except Exception, exc: # Catch all errors
 			Log.exception()
-			self.error_thunk(exc)
+			if ran_init_thunk: self.error_handler(exc, 1, init_val)
+			else: self.error_handler(exc, None, None)
 			raise exc
 
+	def default_init_thunk(self): return None
+	def default_final_func(self, init_val): return init_val
+	def default_error_handler(self, exc, ran_init, init_val): pass
+
 
 class Robust:
 	"""Contains various file operations made safer using tempfiles"""
-	null_action = RobustAction(lambda: None, lambda: None, lambda e: None)
-	def chain(robust_action_list):
+	null_action = RobustAction(None, None, None)
+	def chain(*robust_action_list):
 		"""Return chain tying together a number of robust actions
 
 		The whole chain will be aborted if some error occurs in
 		initialization stage of any of the component actions.
 
 		"""
-		ras_with_completed_inits = []
+		ras_with_started_inits, init_return_vals = [], []
 		def init():
 			for ra in robust_action_list:
-				ras_with_completed_inits.append(ra)
-				ra.init_thunk()
-		def final():
-			for ra in robust_action_list: ra.final_thunk()
-		def error(exc):
-			for ra in ras_with_completed_inits: ra.error_thunk(exc)
+				ras_with_started_inits.append(ra)
+				init_return_vals.append(ra.init_thunk())
+			return init_return_vals
+		def final(init_return_vals):
+			final_vals = []
+			for ra, init_val in zip(robust_action_list, init_return_vals):
+				final_vals.append(ra.final_func(init_val))
+			return final_vals
+		def error(exc, ran_init, init_val):
+			for ra, init_val in zip(ras_with_started_inits, init_return_vals):
+				ra.error_handler(exc, 1, init_val)
+			for ra in ras_with_started_inits[len(init_return_vals):]:
+				ra.error_handler(exc, None, None)
 		return RobustAction(init, final, error)
 
-	def chain_nested(robust_action_list):
+	def chain_nested(*robust_action_list):
 		"""Like chain but final actions performed in reverse order"""
-		ras_with_completed_inits = []
+		ras_with_started_inits, init_vals = [], []
 		def init():
 			for ra in robust_action_list:
-				ras_with_completed_inits.append(ra)
-				ra.init_thunk()
-		def final():
-			ralist_copy = robust_action_list[:]
-			ralist_copy.reverse()
-			for ra in ralist_copy: ra.final_thunk()
-		def error(exc):
-			for ra in ras_with_completed_inits: ra.error_thunk(exc)
+				ras_with_started_inits.append(ra)
+				init_vals.append(ra.init_thunk())
+			return init_vals
+		def final(init_vals):
+			ras_and_inits = zip(robust_action_list, init_vals)
+			ras_and_inits.reverse()
+			final_vals = []
+			for ra, init_val in ras_and_inits:
+				final_vals.append(ra.final_func(init_val))
+			return final_vals
+		def error(exc, ran_init, init_val):
+			for ra, init_val in zip(ras_with_started_inits, init_return_vals):
+				ra.error_handler(exc, 1, init_val)
+			for ra in ras_with_started_inits[len(init_return_vals):]:
+				ra.error_handler(exc, None, None)
 		return RobustAction(init, final, error)
 
 	def make_tf_robustaction(init_thunk, tempfiles, final_renames = None):
@@ -107,18 +136,19 @@ class Robust:
 		create RobustActions of that type.
 
 		"""
-		assert type(tempfiles) is types.TupleType, tempfiles
-		if final_renames is None: final = lambda: None
-		else:
-			assert len(tempfiles) == len(final_renames)
-			def final(): # rename tempfiles to final positions
-				for i in range(len(tempfiles)):
-					final_name = final_renames[i]
-					if final_name:
-						if final_name.isdir(): # Cannot rename over directory
-							final_name.delete()
-						tempfiles[i].rename(final_name)
-		def error(exc):
+		if isinstance(tempfiles, TempFile): tempfiles = (tempfiles,)
+		if isinstance(final_renames, RPath): final_renames = (final_renames,)
+		if final_renames is None: final_renames = [None] * len(tempfiles)
+		assert len(tempfiles) == len(final_renames)
+
+		def final(init_val): # rename tempfiles to final positions
+			for tempfile, destination in zip(tempfiles, final_renames):
+				if destination:
+					if destination.isdir(): # Cannot rename over directory
+						destination.delete()
+					tempfile.rename(destination)
+			return init_val
+		def error(exc, ran_init, init_val):
 			for tf in tempfiles: tf.delete()
 		return RobustAction(init_thunk, final, error)
 
@@ -130,36 +160,46 @@ class Robust:
 		overwritten).
 		
 		"""
-		tfl = [None] # Need mutable object that init and final can access
+		tfl = [None] # Need some mutable state to hold tf value
 		def init(): 
 			if not (rorpin.isdir() and rpout.isdir()): # already a dir
-				tfl[0] = TempFileManager.new(rpout)
-				if rorpin.isreg(): tfl[0].write_from_fileobj(rorpin.open("rb"))
+				tfl[0] = tf = TempFileManager.new(rpout)
+				if rorpin.isreg(): tf.write_from_fileobj(rorpin.open("rb"))
 				else: RPath.copy(rorpin, tf)
-		def final():
-			if tfl[0] and tfl[0].lstat():
+				return tf
+			else: return None
+		def final(tf):
+			if tf and tf.lstat():
 				if rpout.isdir(): rpout.delete()
-				tfl[0].rename(rpout)
-		return RobustAction(init, final, lambda e: tfl[0] and tfl[0].delete())
+				tf.rename(rpout)
+			return rpout
+		def error(exc, ran_init, init_val):
+			if tfl[0]: tfl[0].delete()
+		return RobustAction(init, final, error)
 
 	def copy_with_attribs_action(rorpin, rpout, compress = None):
 		"""Like copy_action but also copy attributes"""
-		tfl = [None] # Need mutable object that init and final can access
+		tfl = [None] # Need some mutable state for error handler
 		def init(): 
 			if not (rorpin.isdir() and rpout.isdir()): # already a dir
-				tfl[0] = TempFileManager.new(rpout)
+				tfl[0] = tf = TempFileManager.new(rpout)
 				if rorpin.isreg():
-					tfl[0].write_from_fileobj(rorpin.open("rb"), compress)
-				else: RPath.copy(rorpin, tfl[0])
-				if tfl[0].lstat(): # Some files, like sockets, won't be created
-					RPathStatic.copy_attribs(rorpin, tfl[0])
-		def final():
+					tf.write_from_fileobj(rorpin.open("rb"), compress)
+				else: RPath.copy(rorpin, tf)
+				if tf.lstat(): # Some files, like sockets, won't be created
+					RPathStatic.copy_attribs(rorpin, tf)
+				return tf
+			else: return None
+		def final(tf):
 			if rorpin.isdir() and rpout.isdir():
 				RPath.copy_attribs(rorpin, rpout)
-			elif tfl[0] and tfl[0].lstat():
-				if rpout.isdir(): rpout.delete()
-				tfl[0].rename(rpout)
-		return RobustAction(init, final, lambda e: tfl[0] and tfl[0].delete())
+			elif tf and tf.lstat():
+				if rpout.isdir(): rpout.delete() # can't rename over dir
+				tf.rename(rpout)
+			return rpout
+		def error(exc, ran_init, init_val):
+			if tfl[0]: tfl[0].delete()
+		return RobustAction(init, final, error)
 
 	def copy_attribs_action(rorpin, rpout):
 		"""Return action which just copies attributes
@@ -168,14 +208,16 @@ class Robust:
 		normal sequence.
 
 		"""
-		def final(): RPath.copy_attribs(rorpin, rpout)
-		return RobustAction(lambda: None, final, lambda e: None)
+		def final(init_val):
+			RPath.copy_attribs(rorpin, rpout)
+			return rpout
+		return RobustAction(None, final, None)
 
 	def symlink_action(rpath, linktext):
 		"""Return symlink action by moving one file over another"""
 		tf = TempFileManager.new(rpath)
 		def init(): tf.symlink(linktext)
-		return Robust.make_tf_robustaction(init, (tf,), (rpath,))
+		return Robust.make_tf_robustaction(init, tf, rpath)
 
 	def destructive_write_action(rp, s):
 		"""Return action writing string s to rpath rp in robust way
@@ -187,9 +229,9 @@ class Robust:
 		def init():
 			fp = tf.open("wb")
 			fp.write(s)
-			assert not fp.close()
+			fp.close()
 			tf.setdata()
-		return Robust.make_tf_robustaction(init, (tf,), (rp,))
+		return Robust.make_tf_robustaction(init, tf, rp)
 
 	def check_common_error(init_thunk, error_thunk = lambda exc: None):
 		"""Execute init_thunk, if error, run error_thunk on exception
@@ -357,8 +399,8 @@ class SaveState:
 			symtext = apply(os.path.join,
 							('increments',) + last_file_rorp.index)
 			return Robust.symlink_action(cls._last_file_sym, symtext)
-		else: return RobustAction(lambda: None, cls.touch_last_file,
-								  lambda exc: None)
+		else: return RobustAction(None, lambda init_val: cls.touch_last_file(),
+								  None)
 
 	def checkpoint(cls, ITR, finalizer, last_file_rorp, override = None):
 		"""Save states of tree reducer and finalizer during inc backup
@@ -372,9 +414,9 @@ class SaveState:
 		cls._last_checkpoint_time = time.time()
 		Log("Writing checkpoint time %s" % cls._last_checkpoint_time, 7)
 		state_string = cPickle.dumps((ITR, finalizer))
-		Robust.chain([Robust.destructive_write_action(cls._checkpoint_rp,
-													  state_string),
-					  cls.record_last_file_action(last_file_rorp)]).execute()
+		Robust.chain(Robust.destructive_write_action(cls._checkpoint_rp,
+													 state_string),
+					 cls.record_last_file_action(last_file_rorp)).execute()
 
 	def checkpoint_needed(cls):
 		"""Returns true if another checkpoint is called for"""
diff --git a/rdiff-backup/src/rorpiter.py b/rdiff-backup/src/rorpiter.py
index fb30426..1ff0724 100644
--- a/rdiff-backup/src/rorpiter.py
+++ b/rdiff-backup/src/rorpiter.py
@@ -212,13 +212,13 @@ class RORPIter:
 		"""Return action patching basisrp using diff_rorp"""
 		assert diff_rorp, "Missing diff index %s" % basisrp.index
 		if not diff_rorp.lstat():
-			return RobustAction(lambda: None, basisrp.delete, lambda e: None)
+			return RobustAction(None, lambda init_val: basisrp.delete(), None)
 
 		if Globals.preserve_hardlinks and diff_rorp.isflaglinked():
 			if not basisrp: basisrp = base_rp.new_index(diff_rorp.index)
-			return RobustAction(lambda: None,
-								lambda: Hardlink.link_rp(diff_rorp, basisrp),
-								lambda e: None)
+			tf = TempFileManager.new(basisrp)
+			def init(): Hardlink.link_rp(diff_rorp, tf, basisrp)
+			return Robust.make_tf_robustaction(init, tf, basisrp)
 		elif basisrp and basisrp.isreg() and diff_rorp.isreg():
 			assert diff_rorp.get_attached_filetype() == 'diff'
 			return Rdiff.patch_with_attribs_action(basisrp, diff_rorp)
diff --git a/rdiff-backup/src/statistics.py b/rdiff-backup/src/statistics.py
index 8269456..c18f34a 100644
--- a/rdiff-backup/src/statistics.py
+++ b/rdiff-backup/src/statistics.py
@@ -16,13 +16,29 @@ class StatsObj:
 					   'DeletedFiles', 'DeletedFileSize',
 					   'ChangedFiles',
 					   'ChangedSourceSize', 'ChangedMirrorSize',
-					   'IncrementFileSize')
+					   'IncrementFiles', 'IncrementFileSize')
 	stat_time_attrs = ('StartTime', 'EndTime', 'ElapsedTime')
-	stat_attrs = stat_time_attrs + stat_file_attrs
+	stat_attrs = ('Filename',) + stat_time_attrs + stat_file_attrs
+
+	# Below, the second value in each pair is true iff the value
+	# indicates a number of bytes
+	stat_file_pairs = (('SourceFiles', None), ('SourceFileSize', 1),
+					   ('MirrorFiles', None), ('MirrorFileSize', 1),
+					   ('NewFiles', None), ('NewFileSize', 1),
+					   ('DeletedFiles', None), ('DeletedFileSize', 1),
+					   ('ChangedFiles', None),
+					   ('ChangedSourceSize', 1), ('ChangedMirrorSize', 1),
+					   ('IncrementFiles', None), ('IncrementFileSize', 1))
 
 	# Set all stats to None, indicating info not available
 	for attr in stat_attrs: locals()[attr] = None
 
+	# This is used in get_byte_summary_string below
+	byte_abbrev_list = ((1024*1024*1024*1024, "TB"),
+						(1024*1024*1024, "GB"),
+						(1024*1024, "MB"),
+						(1024, "KB"))
+
 	def get_stat(self, attribute):
 		"""Get a statistic"""
 		try: return self.__dict__[attribute]
@@ -34,33 +50,89 @@ class StatsObj:
 		"""Set attribute to given value"""
 		self.__dict__[attr] = value
 
+	def get_stats_line(self, index):
+		"""Return one line abbreviated version of full stats string"""
+		file_attrs = map(lambda attr: str(self.get_stat(attr)),
+						 self.stat_file_attrs)
+		if not index: filename = "."
+		else:
+			# use repr to quote newlines in relative filename, then
+			# take of leading and trailing quote.
+			filename = repr(apply(os.path.join, index))[1:-1]
+		return " ".join([filename,] + file_attrs)
+
+	def set_stats_from_line(self, line):
+		"""Set statistics from given line"""
+		def error(): raise StatsException("Bad line '%s'" % line)
+		if line[-1] == "\n": line = line[:-1]
+		lineparts = line.split(" ")
+		if len(lineparts) < len(stat_file_attrs): error()
+		for attr, val_string in zip(stat_file_attrs,
+									lineparts[-len(stat_file_attrs):]):
+			try: val = long(val_string)
+			except ValueError:
+				try: val = float(val_string)
+				except ValueError: error()
+			self.set_stat(attr, val)
+		return self
+
 	def get_stats_string(self):
-		"""Return string printing out statistics"""
+		"""Return extended string printing out statistics"""
+		return self.get_timestats_string() + self.get_filestats_string()
+
+	def get_timestats_string(self):
+		"""Return portion of statistics string dealing with time"""
 		timelist = []
 		if self.StartTime is not None:
-			timelist.append("StartTime %s (%s)\n" %
+			timelist.append("StartTime %.2f (%s)\n" %
 						(self.StartTime, Time.timetopretty(self.StartTime)))
 		if self.EndTime is not None:
-			timelist.append("EndTime %s (%s)\n" %
+			timelist.append("EndTime %.2f (%s)\n" %
 							(self.EndTime, Time.timetopretty(self.EndTime)))
-		if self.StartTime is not None and self.EndTime is not None:
+		if self.ElapsedTime or (self.StartTime is not None and
+								self.EndTime is not None):
 			if self.ElapsedTime is None:
 				self.ElapsedTime = self.EndTime - self.StartTime
-			timelist.append("ElapsedTime %s (%s)\n" %
+			timelist.append("ElapsedTime %.2f (%s)\n" %
 				   (self.ElapsedTime, Time.inttopretty(self.ElapsedTime)))
+		return "".join(timelist)
+
+	def get_filestats_string(self):
+		"""Return portion of statistics string about files and bytes"""
+		def fileline(stat_file_pair):
+			"""Return zero or one line of the string"""
+			attr, in_bytes = stat_file_pair
+			val = self.get_stat(attr)
+			if val is None: return ""
+			if in_bytes:
+				return "%s %s (%s)\n" % (attr, val,
+										 self.get_byte_summary_string(val))
+			else: return "%s %s\n" % (attr, val)
+
+		return "".join(map(fileline, self.stat_file_pairs))
 
-		filelist = ["%s %s\n" % (attr, self.get_stat(attr))
-					for attr in self.stat_file_attrs
-					if self.get_stat(attr) is not None]
-		return "".join(timelist + filelist)
+	def get_byte_summary_string(self, byte_count):
+		"""Turn byte count into human readable string like "7.23GB" """
+		for abbrev_bytes, abbrev_string in self.byte_abbrev_list:
+			if byte_count >= abbrev_bytes:
+				# Now get 3 significant figures
+				abbrev_count = float(byte_count)/abbrev_bytes
+				if abbrev_count >= 100: precision = 0
+				elif abbrev_count >= 10: precision = 1
+				else: precision = 2
+				return "%%.%df %s" % (precision, abbrev_string) \
+					   % (abbrev_count,)
+		byte_count = round(byte_count)
+		if byte_count == 1: return "1 byte"
+		else: return "%d bytes" % (byte_count,)
 
 	def get_stats_logstring(self, title):
 		"""Like get_stats_string, but add header and footer"""
-		header = "-------------[ %s ]-------------" % title
+		header = "--------------[ %s ]--------------" % title
 		footer = "-" * len(header)
 		return "%s\n%s%s\n" % (header, self.get_stats_string(), footer)
 
-	def init_stats_from_string(self, s):
+	def set_stats_from_string(self, s):
 		"""Initialize attributes from string, return self for convenience"""
 		def error(line): raise StatsException("Bad line '%s'" % line)
 
@@ -91,7 +163,7 @@ class StatsObj:
 	def read_stats_from_rp(self, rp):
 		"""Set statistics from rpath, return self for convenience"""
 		fp = rp.open("r")
-		self.init_stats_from_string(fp.read())
+		self.set_stats_from_string(fp.read())
 		fp.close()
 		return self
 
@@ -162,22 +234,96 @@ class StatsITR(IterTreeReducer, StatsObj):
 					self.ChangedFiles += 1
 					self.ChangedSourceSize += mirror_dsrp.getsize()
 					self.ChangedMirrorSize += self.mirror_base_size
-					self.IncrementFileSize += inc_rp and inc_rp.getsize() or 0
+					if inc_rp:
+						self.IncrementFiles += 1
+						self.IncrementFileSize += inc_rp.getsize()
 			else: # new file was created
 				self.NewFiles += 1
 				self.NewFileSize += mirror_dsrp.getsize()
-				self.IncrementFileSize += inc_rp and inc_rp.getsize() or 0
+				if inc_rp:
+					self.IncrementFiles += 1
+					self.IncrementFileSize += inc_rp.getsize()
 		else:
 			if self.mirror_base_exists: # file was deleted from mirror
 				self.MirrorFiles += 1
 				self.MirrorFileSize += self.mirror_base_size
 				self.DeletedFiles += 1
 				self.DeletedFileSize += self.mirror_base_size
-				self.IncrementFileSize += inc_rp and inc_rp.getsize() or 0
-
+				if inc_rp:
+					self.IncrementFiles += 1
+					self.IncrementFileSize += inc_rp.getsize()
 
 	def add_file_stats(self, subinstance):
 		"""Add all file statistics from subinstance to current totals"""
 		for attr in self.stat_file_attrs:
 			self.set_stat(attr,
 						  self.get_stat(attr) + subinstance.get_stat(attr))
+
+
+class Stats:
+	"""Misc statistics methods, pertaining to dir and session stat files"""
+	# This is the RPath of the directory statistics file, and the
+	# associated open file.  It will hold a line of statistics for
+	# each directory that is backed up.
+	_dir_stats_rp = None
+	_dir_stats_fp = None
+
+	# This goes at the beginning of the directory statistics file and
+	# explains the format.
+	_dir_stats_header = """# rdiff-backup directory statistics file
+#
+# Each line is in the following format:
+# RelativeDirName %s
+""" % " ".join(StatsObj.stat_file_attrs)
+
+	def open_dir_stats_file(cls):
+		"""Open directory statistics file, write header"""
+		assert not cls._dir_stats_fp, "Directory file already open"
+
+		if Globals.compression: suffix = "data.gz"
+		else: suffix = "data"
+		cls._dir_stats_rp = Inc.get_inc(Globals.rbdir.append(
+			"directory_statistics"), Time.curtime, suffix)
+
+		if cls._dir_stats_rp.lstat():
+			Log("Warning, statistics file %s already exists, appending", 2)
+			cls._dir_stats_fp = cls._dir_stats_rp.open("ab",
+													   Globals.compression)
+		else: cls._dir_stats_fp = \
+			  cls._dir_stats_rp.open("wb", Globals.compression)
+		cls._dir_stats_fp.write(cls._dir_stats_header)
+
+	def write_dir_stats_line(cls, statobj, index):
+		"""Write info from statobj about rpath to statistics file"""
+		cls._dir_stats_fp.write(statobj.get_stats_line(index) +"\n")
+
+	def close_dir_stats_file(cls):
+		"""Close directory statistics file if its open"""
+		if cls._dir_stats_fp:
+			cls._dir_stats_fp.close()
+			cls._dir_stats_fp = None
+
+	def write_session_statistics(cls, statobj):
+		"""Write session statistics into file, log"""
+		stat_inc = Inc.get_inc(Globals.rbdir.append("session_statistics"),
+							   Time.curtime, "data")
+		statobj.StartTime = Time.curtime
+		statobj.EndTime = time.time()
+
+		# include hardlink data and dir stats in size of increments
+		if Globals.preserve_hardlinks and Hardlink.final_inc:
+			# include hardlink data in size of increments
+			statobj.IncrementFiles += 1
+			statobj.IncrementFileSize += Hardlink.final_inc.getsize()
+		if cls._dir_stats_rp and cls._dir_stats_rp.lstat():
+			statobj.IncrementFiles += 1
+			statobj.IncrementFileSize += cls._dir_stats_rp.getsize()
+
+		statobj.write_stats_to_rp(stat_inc)
+		if Globals.print_statistics:
+			message = statobj.get_stats_logstring("Session statistics")
+			Log.log_to_file(message)
+			Globals.client_conn.sys.stdout.write(message)
+
+MakeClass(Stats)
+
diff --git a/rdiff-backup/src/ttime.py b/rdiff-backup/src/ttime.py
index bfa3c6f..852f6ea 100644
--- a/rdiff-backup/src/ttime.py
+++ b/rdiff-backup/src/ttime.py
@@ -95,7 +95,9 @@ class Time:
 
 		if seconds == 1: partlist.append("1 second")
 		elif not partlist or seconds > 1:
-			partlist.append("%s seconds" % seconds)
+			if isinstance(seconds, int) or isinstance(seconds, long):
+				partlist.append("%s seconds" % seconds)
+			else: partlist.append("%.2f seconds" % seconds)
 		return " ".join(partlist)
 
 	def intstringtoseconds(cls, interval_string):