add doc strings, and limit what functions are exposed..

__init__.py

@@ -13,9 +13,19 @@ import unittest
 
 _encoding = 'utf-8'
 
+__all__ = [ 'validate' ]
+
 class Storage:
+	'''A class to help read pieces of a torrent.
+	'''
 
 	def __init__(self, rootpath, files, piecelen):
+		'''
+		rootpath - path to the dir of torrent files are in
+		files - the files dictionary from the torrent info key
+		piecelen - piece length from the torren info key
+		'''
+
 		self._rootpath = pathlib.Path(rootpath)
 		self._files = files
 		self._piecelen = piecelen
@@ -40,10 +50,16 @@ class Storage:
 			yield curfile, fname, curfilepath
 
 	def allfiles(self):
+		'''Iterator that returns each on disk path name for
+		each file.'''
+
 		for x, y, curfilepath in self._filepaths():
 			yield curfilepath
 
 	def _buildindex(self):
+		'''Internal function to build the needed indexes for
+		pieces and files.'''
+
 		self._pieceindex = []
 		self._fileindex = {}
 		files = self._filepaths()
@@ -75,19 +91,37 @@ class Storage:
 			left -= sz
 
 	def filepieces(self):
+		'''Iterator that returns a pair, first item is the subpath
+		to a file (that is relative to the torrent dir), and the
+		pieces that cover the file.'''
+
 		return self._fileindex.items()
 
 	def filesforpiece(self, idx):
+		'''Return a list of files that are covered by piece idx.'''
+
 		for x in self._pieceindex[idx]:
 			yield x['file']
 
 	def apply_piece(self, idx, fun):
+		'''Read the parts of piece idx, and call fun w/ each part.
+
+		This is to hash the parts, e.g.
+		hash = sha1()
+		stor.apply_piece(num, hash.update)
+
+		hash now contains the digest for the piece.'''
+
 		for i in self._pieceindex[idx]:
 			with open(i['file'], 'rb') as fp:
 				fp.seek(i['offset'])
 				fun(fp.read(i['size']))
 
 def validate(torrent, basedir):
+	'''Take a decode torrent file, where it was stored in basedir,
+	verify the torrent.  Returns a pair of set, the first is all the
+	files that are valid, the second are all the invalid files.'''
+
 	info = torrent['info']
 
 	basedir = pathlib.Path(basedir)