IGN:Make job control a little more robust

src/calibre/ebooks/epub/from_html.py

@@ -77,6 +77,8 @@ def check_links(opf_path, pretty_print):
                 html_files.append(os.path.abspath(content(f)))
         
         for path in html_files:
+            if not os.access(path, os.R_OK):
+                continue
             base = os.path.dirname(path)
             root = html.fromstring(open(content(path), 'rb').read(), parser=parser)
             for element, attribute, link, pos in list(root.iterlinks()):

src/calibre/parallel.py

@@ -286,7 +286,7 @@ def write(socket, msg, timeout=5):
 def read(socket, timeout=5):
     '''
     Read a message from `socket`. The message must have been sent with the :function:`write`
-    function. Raises a `RuntimeError` if the message is corrpted. Can return an
+    function. Raises a `RuntimeError` if the message is corrupted. Can return an
     empty string.
     '''
     if isworker:
@@ -299,7 +299,12 @@ def read(socket, timeout=5):
             if not msg:
                 break
             if length is None:
-                length, msg = int(msg[:12]), msg[12:]
+                try:
+                    length, msg = int(msg[:12]), msg[12:]
+                except ValueError:
+                    if DEBUG:
+                        print >>sys.__stdout__, 'read(%s):'%('worker' if isworker else 'overseer'), 'no length in', msg
+                    return ''
             buf.write(msg)
             if buf.tell() >= length:
                 break