better PDF generation logic; add cleanup()

try to make the PDF first with jw, but don't quit if that fails
fall back to PDF generation with dblatex and tell the user
cleanup any generated index.sgml (if we made it)

tldp/doctypes/docbooksgml.py

@@ -4,6 +4,7 @@
 from __future__ import absolute_import, division, print_function
 
 import os
+import errno
 import logging
 import networkx as nx
 
@@ -52,6 +53,26 @@ class DocbookSGML(BaseDoctype, SignatureChecker):
 
     buildorder = ['buildall']
 
+    def cleanup(self):
+        stem = self.source.stem
+        removals = getattr(self, 'removals', None)
+        if removals:
+            for fn in removals:
+                logger.debug("%s cleaning up file %s", stem, fn)
+                try:
+                    os.unlink(fn)
+                except OSError as e:
+                    if e.errno is errno.ENOENT:
+                        logger.error("%s missing file at cleanup %s", stem, fn)
+                    else:
+                        raise e
+
+    def hook_build_success(self):
+        self.cleanup()
+
+    def hook_build_failure(self):
+        self.cleanup()
+
     def chdir_output(self):
         os.chdir(self.output.dirname)
         return True
@@ -97,8 +118,8 @@ class DocbookSGML(BaseDoctype, SignatureChecker):
                  -- "index.sgml" "{source.dirname}/index.sgml"'''
         moved = self.shellscript(s)
         if moved:
-            self.removals = indexsgml
             logger.debug("%s created %s", self.source.stem, indexsgml)
+            self.removals = [indexsgml]
             return True
         return os.path.exists(indexsgml)
 
@@ -162,8 +183,16 @@ class DocbookSGML(BaseDoctype, SignatureChecker):
 
     @depends(graph, cleaned_indexsgml)
     def make_name_pdf(self):
+        stem = self.source.stem
+        classname = self.__class__.__name__
+        logger.info("%s calling method %s.%s",
+                    stem, classname, 'make_pdf_with_jw')
         if self.make_pdf_with_jw():
              return True
+        logger.error("%s jw failed creating PDF, falling back to dblatex...",
+                     stem)
+        logger.info("%s calling method %s.%s",
+                    stem, classname, 'make_pdf_with_dblatex')
         return self.make_pdf_with_dblatex()
 
     @depends(graph, make_name_htmls)