protocol: convert StreamException to generated error code

This makes it much easier to handle these errors at the transport level.

mercurial/streamclone.py

@@ -1,69 +1,63 b''
 # streamclone.py - streaming clone server support for mercurial
 #
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 import util, error
-
 from mercurial import store
 
-class StreamException(Exception):
-    def __init__(self, code):
-        Exception.__init__(self)
-        self.code = code
-    def __str__(self):
-        return '%i\n' % self.code
-
 # if server supports streaming clone, it advertises "stream"
 # capability with value that is version+flags of repo it is serving.
 # client only streams if it can read that repo format.
 
 # stream file format is simple.
 #
 # server writes out line that says how many files, how many total
 # bytes.  separator is ascii space, byte counts are strings.
 #
 # then for each file:
 #
 #   server writes out line that says filename, how many bytes in
 #   file.  separator is ascii nul, byte count is string.
 #
 #   server writes out raw file data.
 
 def allowed(ui):
     return ui.configbool('server', 'uncompressed', True, untrusted=True)
 
 def stream_out(repo):
     '''stream out all metadata files in repository.
     writes to file-like object, must support write() and optional flush().'''
 
     if not allowed(repo.ui):
-        raise StreamException(1)
+        yield '1\n' # error: 1
+        return
 
     entries = []
     total_bytes = 0
     try:
         # get consistent snapshot of repo, lock during scan
         lock = repo.lock()
         try:
             repo.ui.debug('scanning\n')
             for name, ename, size in repo.store.walk():
                 entries.append((name, size))
                 total_bytes += size
         finally:
             lock.release()
     except error.LockError:
-        raise StreamException(2)
+        yield '2\n' # error: 2
+        return
 
-    yield '0\n'
+    yield '0\n' # success
     repo.ui.debug('%d files, %d bytes to transfer\n' %
                   (len(entries), total_bytes))
     yield '%d %d\n' % (len(entries), total_bytes)
     for name, size in entries:
         repo.ui.debug('sending %s (%d bytes)\n' % (name, size))
         # partially encode name over the wire for backwards compat
         yield '%s\0%d\n' % (store.encodedir(name), size)
         for chunk in util.filechunkiter(repo.sopener(name), limit=size):
             yield chunk