# 
# 
# patch "viewmtn.py"
#  from [25ef3613dbdc3d4bbf01f2924a3955f6713e7647]
#    to [0443b09ed056e81f2c97a511d0612f9dcc05f6c1]
# 
============================================================
--- viewmtn.py	25ef3613dbdc3d4bbf01f2924a3955f6713e7647
+++ viewmtn.py	0443b09ed056e81f2c97a511d0612f9dcc05f6c1
@@ -326,10 +326,12 @@ class Tags:
         tags = map(None, ops.tags())
         tags.sort(lambda t1, t2: cmp(t1.name, t2.name))
         def revision_ago(rev):
+            rv = ""
             for cert in ops.certs(rev):
                 if cert[4] == 'name' and cert[5] == 'date':
                     revdate = common.parse_timecert(cert[7])
-                    return common.ago(revdate)
+                    rv = common.ago(revdate)
+            return rv
         renderer.render('tags.html', page_title="Tags", tags=tags, revision_ago=revision_ago)
 
 class Help:
@@ -337,8 +339,8 @@ class BranchChanges:
         renderer.render('help.html', page_title="Help")
 
 class BranchChanges:
-    def get_last_changes(self, branch, from_change, to_change):
-        revs = map(None, ops.heads(branch.name))
+    def get_last_changes(self, branch, heads, from_change, to_change):
+        revs = heads
         if len(revs) == 0:
             raise Exception("get_last_changes() unable to find somewhere to start - probably a non-existent branch?")
         to_parent = revs+[] # copy
@@ -412,6 +414,9 @@ class BranchChanges:
             return rv
         
         branch = mtn.Branch(branch)
+        heads = [t for t in ops.heads(branch.name)]
+        if not heads:
+            return web.notfound()
         per_page = 10
         if from_change:
             from_change = int(from_change)
@@ -421,7 +426,7 @@ class BranchChanges:
             to_change = int(to_change)
         else:
             to_change = per_page
-        changed, new_starting_point = self.get_last_changes(branch, from_change, to_change)
+        changed, new_starting_point = self.get_last_changes(branch, heads, from_change, to_change)
         # next and previous 'from' and 'to' indexes
         if len(changed) == to_change - from_change:
             next_from, next_to = to_change, to_change + per_page
@@ -453,7 +458,7 @@ class RSSBranchChanges(BranchChanges):
     def GET(self, branch, from_change, to_change):
         BranchChanges.GET(self, branch, from_change, to_change, "branchchangesrss.html")
 
-class RevisionPage:
+class RevisionPage(object):
     def get_fileid(self, revision, filename):
         rv = None
         for stanza in ops.get_manifest_of(revision):
@@ -462,6 +467,12 @@ class RevisionPage:
             if stanza[1] == filename:
                 rv = stanza[3]
         return rv
+    def exists(self, revision):
+        try:
+            certs = [t for t in ops.certs(revision)]
+            return True
+        except mtn.MonotoneException:
+            return False
     def branches_for_rev(self, revisions_val):
         rv = []
         for stanza in ops.certs(revisions_val):
@@ -472,6 +483,8 @@ class RevisionInfo(RevisionPage):
 class RevisionInfo(RevisionPage):
     def GET(self, revision):
         revision = mtn.Revision(revision)
+        if not self.exists(revision):
+            return web.notfound()
         certs = ops.certs(revision)
         revisions = ops.get_revision(revision)
         output_png, output_imagemap = ancestry_graph(revision)
@@ -492,6 +505,10 @@ class RevisionDiff(RevisionPage):
     def GET(self, revision_from, revision_to, filename=None):
         revision_from = mtn.Revision(revision_from)
         revision_to = mtn.Revision(revision_to)
+        if not self.exists(revision_from):
+            return web.notfound()
+        if not self.exists(revision_to):
+            return web.notfound()
         if filename != None:
             files = [filename]
         else:
@@ -508,6 +525,8 @@ class RevisionFile(RevisionPage):
 class RevisionFile(RevisionPage):
     def GET(self, revision, filename):
         revision = mtn.Revision(revision)
+        if not self.exists(revision_to):
+            return web.notfound()
         language = filename.rsplit('.', 1)[-1]
         fileid = RevisionPage.get_fileid(self, revision, filename)
         if not fileid:
@@ -515,9 +534,11 @@ class RevisionFile(RevisionPage):
         contents = ops.get_file(fileid)
         mimetype = mimehelp.lookup(filename, '')
         mime_to_template = {
-            'image/jpeg' : 'revisionfileimg.html', 
-            'image/png'  : 'revisionfileimg.html', 
-            'image/gif'  : 'revisionfileimg.html'
+            'image/jpeg'           : 'revisionfileimg.html', 
+            'image/png'            : 'revisionfileimg.html', 
+            'image/gif'            : 'revisionfileimg.html',
+            'application/x-python' : 'revisionfiletxt.html', 
+            'application/x-perl'   : 'revisionfiletxt.html', 
         }
         template = mime_to_template.get(mimetype, None)
         if not template:
@@ -536,6 +557,8 @@ class RevisionDownloadFile(RevisionPage)
     def GET(self, revision, filename):
         web.header('Content-Disposition', 'attachment; filename=%s' % filename)
         revision = mtn.Revision(revision)
+        if not self.exists(revision_to):
+            return web.notfound()
         fileid = RevisionPage.get_fileid(self, revision, filename)
         if not fileid:
             return web.notfound()
@@ -546,11 +569,13 @@ class RevisionDownloadFile(RevisionPage)
             sys.stdout.write(data)
         sys.stdout.flush()
 
-class RevisionTar:
+class RevisionTar(RevisionPage):
     def GET(self, revision):
         # we'll output in the USTAR tar format; documentation taken from:
         # http://en.wikipedia.org/wiki/Tar_%28file_format%29
         revision = mtn.Revision(revision)
+        if not self.exists(revision_to):
+            return web.notfound()
         web.header('Content-Disposition', 'attachment; filename=%s.tar' % revision)
         web.header('Content-Type', 'application/x-tar')
         manifest = [stanza for stanza in ops.get_manifest_of(revision)]
@@ -590,6 +615,8 @@ class RevisionBrowse(RevisionPage):
 class RevisionBrowse(RevisionPage):
     def GET(self, revision, path):
         revision = mtn.Revision(revision)
+        if not self.exists(revision_to):
+            return web.notfound()
         branches = RevisionPage.branches_for_rev(self, revision)
         revisions = ops.get_revision(revision)