Parse the error codes from the text file if available

The text file was added in PG 9.1. It contains a few errors not available
in the SGML.

scripts/make_errorcodes.py

@@ -16,6 +16,7 @@ The script can be run at a new PostgreSQL release to refresh the module.
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import re
 import sys
 import urllib2
 from collections import defaultdict
@@ -48,7 +49,46 @@ def read_base_file(filename):
 
     raise ValueError("can't find the separator. Is this the right file?")
 
-def parse_errors(url):
+def parse_errors_txt(url):
+    classes = {}
+    errors = defaultdict(dict)
+
+    page = urllib2.urlopen(url)
+    for line in page:
+        # Strip comments and skip blanks
+        line = line.split('#')[0].strip()
+        if not line:
+            continue
+
+        # Parse a section
+        m = re.match(r"Section: (Class (..) - .+)", line)
+        if m:
+            label, class_ = m.groups()
+            classes[class_] = label
+            continue
+
+        # Parse an error
+        m = re.match(r"(.....)\s+(?:E|W|S)\s+ERRCODE_(\S+)(?:\s+(\S+))?$", line)
+        if m:
+            errcode, macro, spec = m.groups()
+            # error 22008 has 2 macros and 1 def: give priority to the def
+            # as it's the one we used to parse from sgml
+            if not spec:
+                if errcode in errors[class_]:
+                    continue
+                errlabel = macro.upper()
+            else:
+                errlabel = spec.upper()
+
+            errors[class_][errcode] = errlabel
+            continue
+
+        # We don't expect anything else
+        raise ValueError("unexpected line:\n%s" % line)
+
+    return classes, errors
+
+def parse_errors_sgml(url):
     page = BS(urllib2.urlopen(url))
     table = page('table')[1]('tbody')[0]
 
@@ -87,14 +127,25 @@ def parse_errors(url):
 
     return classes, errors
 
-errors_url="http://www.postgresql.org/docs/%s/static/errcodes-appendix.html"
+errors_sgml_url = \
+        "http://www.postgresql.org/docs/%s/static/errcodes-appendix.html"
+
+errors_txt_url = \
+        "http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob_plain;" \
+        "f=src/backend/utils/errcodes.txt;hb=REL%s_STABLE"
 
 def fetch_errors(versions):
     classes = {}
     errors = defaultdict(dict)
 
     for version in versions:
-        c1, e1 = parse_errors(errors_url % version)
+        print >> sys.stderr, version
+        tver = tuple(map(int, version.split('.')))
+        if tver < (9, 1):
+            c1, e1 = parse_errors_sgml(errors_sgml_url % version)
+        else:
+            c1, e1 = parse_errors_txt(
+                errors_txt_url % version.replace('.', '_'))
         classes.update(c1)
         for c, cerrs in e1.iteritems():
             errors[c].update(cerrs)