largefiles: move protocol conversion into getlfile and make it an iterable

Avoid the intermediate limitreader and filechunkiter between getlfile and
copyandhash - return the right protocol and put the complexity where it better
can be managed.

hgext/largefiles/proto.py

@@ -114,6 +114,7 b' def wirereposetup(ui, repo):'
                         _('putlfile failed (unexpected response):'), ret)
 
         def getlfile(self, sha):
+            """returns an iterable with the chunks of the file with sha sha"""
             stream = self._callstream("getlfile", sha=sha)
             length = stream.readline()
             try:
@@ -121,7 +122,12 b' def wirereposetup(ui, repo):'
             except ValueError:
                 self._abort(error.ResponseError(_("unexpected response:"),
                                                 length))
-            return (length, stream)
+
+            # Mercurial doesn't close SSH connections after writing a stream
+            infile = lfutil.limitreader(stream, length)
+            for chunk in util.filechunkiter(infile, 128 * 1024):
+                yield chunk
+            infile.close()
 
         @batchable
         def statlfile(self, sha):

hgext/largefiles/remotestore.py

@@ -58,7 +58,7 b' class remotestore(basestore.basestore):'
                                'statlfile (%r)' % stat)
 
         try:
-            length, infile = self._get(hash)
+            chunks = self._get(hash)
         except urllib2.HTTPError, e:
             # 401s get converted to util.Aborts; everything else is fine being
             # turned into a StoreError
@@ -71,14 +71,7 b' class remotestore(basestore.basestore):'
         except IOError, e:
             raise basestore.StoreError(filename, hash, self.url, str(e))
 
-        # Mercurial does not close its SSH connections after writing a stream
-        if length is not None:
-            infile = lfutil.limitreader(infile, length)
-        try:
-            return lfutil.copyandhash(util.filechunkiter(infile, 128 * 1024),
-                                      tmpfile)
-        finally:
-            infile.close()
+        return lfutil.copyandhash(chunks, tmpfile)
 
     def _verifyfile(self, cctx, cset, contents, standin, verified):
         filename = lfutil.splitstandin(standin)