[libxml2] Simplify control flow in xmlParseStartTag2

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 07b7428b69c368611d215a140fe630b2d1e61349
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Thu Jun 1 00:19:14 2017 +0200

    Simplify control flow in xmlParseStartTag2
    
    Remove some goto labels and deduplicate a bit of code after handling
    namespaces.
    
    Before:
    
        loop {
            parseAttribute
            if (ok) {
                if (defaultNamespace) {
                    handleDefaultNamespace
                    if (error)
                        goto skip_default_ns;
                    handleDefaultNamespace
        skip_default_ns:
                    freeAttr
                    nextAttr
                    continue;
                }
                if (namespace) {
                    handleNamespace
                    if (error)
                        goto skip_ns;
                    handleNamespace
        skip_ns:
                    freeAttr
                    nextAttr;
                    continue;
                }
                handleAttr
            } else {
                freeAttr
            }
            nextAttr
        }
    
    After:
    
        loop {
            parseAttribute
            if (!ok)
                goto next_attr;
            if (defaultNamespace) {
                handleDefaultNamespace
                if (error)
                    goto next_attr;
                handleDefaultNamespace
            } else if (namespace) {
                handleNamespace
                if (error)
                    goto next_attr;
                handleNamespace
            } else {
                handleAttr
            }
        next_attr:
            freeAttr
            nextAttr
        }

 parser.c |  334 ++++++++++++++++++++++++++++----------------------------------
 1 files changed, 152 insertions(+), 182 deletions(-)
---
diff --git a/parser.c b/parser.c
index 7d8da4f..8d1390b 100644
--- a/parser.c
+++ b/parser.c
@@ -9454,191 +9454,161 @@ reparse:
            attvalue = NULL;
            goto base_changed;
        }
-        if ((attname != NULL) && (attvalue != NULL)) {
-           if (len < 0) len = xmlStrlen(attvalue);
-            if ((attname == ctxt->str_xmlns) && (aprefix == NULL)) {
-               const xmlChar *URL = xmlDictLookup(ctxt->dict, attvalue, len);
-               xmlURIPtr uri;
-
-                if (URL == NULL) {
-                   xmlErrMemory(ctxt, "dictionary allocation failure");
-                   if ((attvalue != NULL) && (alloc != 0))
-                       xmlFree(attvalue);
-                   return(NULL);
-               }
-                if (*URL != 0) {
-                   uri = xmlParseURI((const char *) URL);
-                   if (uri == NULL) {
-                       xmlNsErr(ctxt, XML_WAR_NS_URI,
-                                "xmlns: '%s' is not a valid URI\n",
-                                          URL, NULL, NULL);
-                   } else {
-                       if (uri->scheme == NULL) {
-                           xmlNsWarn(ctxt, XML_WAR_NS_URI_RELATIVE,
-                                     "xmlns: URI %s is not absolute\n",
-                                     URL, NULL, NULL);
-                       }
-                       xmlFreeURI(uri);
-                   }
-                   if (URL == ctxt->str_xml_ns) {
-                       if (attname != ctxt->str_xml) {
-                           xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                        "xml namespace URI cannot be the default namespace\n",
-                                    NULL, NULL, NULL);
-                       }
-                       goto skip_default_ns;
-                   }
-                   if ((len == 29) &&
-                       (xmlStrEqual(URL,
-                                BAD_CAST "http://www.w3.org/2000/xmlns/";))) {
-                       xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                            "reuse of the xmlns namespace name is forbidden\n",
-                                NULL, NULL, NULL);
-                       goto skip_default_ns;
-                   }
-               }
-               /*
-                * check that it's not a defined namespace
-                */
-               for (j = 1;j <= nbNs;j++)
-                   if (ctxt->nsTab[ctxt->nsNr - 2 * j] == NULL)
-                       break;
-               if (j <= nbNs)
-                   xmlErrAttributeDup(ctxt, NULL, attname);
-               else
-                   if (nsPush(ctxt, NULL, URL) > 0) nbNs++;
-skip_default_ns:
-               if ((attvalue != NULL) && (alloc != 0)) {
-                   xmlFree(attvalue);
-                   attvalue = NULL;
-               }
-               if ((RAW == '>') || (((RAW == '/') && (NXT(1) == '>'))))
-                   break;
-               if (!IS_BLANK_CH(RAW)) {
-                   xmlFatalErrMsg(ctxt, XML_ERR_SPACE_REQUIRED,
-                                  "attributes construct error\n");
-                   break;
-               }
-               SKIP_BLANKS;
-               if ((ctxt->input->base != base) || (inputNr != ctxt->inputNr))
-                   goto base_changed;
-               continue;
-           }
-            if (aprefix == ctxt->str_xmlns) {
-               const xmlChar *URL = xmlDictLookup(ctxt->dict, attvalue, len);
-               xmlURIPtr uri;
-
-                if (attname == ctxt->str_xml) {
-                   if (URL != ctxt->str_xml_ns) {
-                       xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                                "xml namespace prefix mapped to wrong URI\n",
-                                NULL, NULL, NULL);
-                   }
-                   /*
-                    * Do not keep a namespace definition node
-                    */
-                   goto skip_ns;
-               }
+        if ((attname == NULL) || (attvalue == NULL))
+            goto next_attr;
+       if (len < 0) len = xmlStrlen(attvalue);
+
+        if ((attname == ctxt->str_xmlns) && (aprefix == NULL)) {
+            const xmlChar *URL = xmlDictLookup(ctxt->dict, attvalue, len);
+            xmlURIPtr uri;
+
+            if (URL == NULL) {
+                xmlErrMemory(ctxt, "dictionary allocation failure");
+                if ((attvalue != NULL) && (alloc != 0))
+                    xmlFree(attvalue);
+                return(NULL);
+            }
+            if (*URL != 0) {
+                uri = xmlParseURI((const char *) URL);
+                if (uri == NULL) {
+                    xmlNsErr(ctxt, XML_WAR_NS_URI,
+                             "xmlns: '%s' is not a valid URI\n",
+                                       URL, NULL, NULL);
+                } else {
+                    if (uri->scheme == NULL) {
+                        xmlNsWarn(ctxt, XML_WAR_NS_URI_RELATIVE,
+                                  "xmlns: URI %s is not absolute\n",
+                                  URL, NULL, NULL);
+                    }
+                    xmlFreeURI(uri);
+                }
                 if (URL == ctxt->str_xml_ns) {
-                   if (attname != ctxt->str_xml) {
-                       xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                                "xml namespace URI mapped to wrong prefix\n",
-                                NULL, NULL, NULL);
-                   }
-                   goto skip_ns;
-               }
-                if (attname == ctxt->str_xmlns) {
-                   xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                            "redefinition of the xmlns prefix is forbidden\n",
-                            NULL, NULL, NULL);
-                   goto skip_ns;
-               }
-               if ((len == 29) &&
-                   (xmlStrEqual(URL,
-                                BAD_CAST "http://www.w3.org/2000/xmlns/";))) {
-                   xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                            "reuse of the xmlns namespace name is forbidden\n",
-                            NULL, NULL, NULL);
-                   goto skip_ns;
-               }
-               if ((URL == NULL) || (URL[0] == 0)) {
-                   xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
-                            "xmlns:%s: Empty XML namespace is not allowed\n",
-                                 attname, NULL, NULL);
-                   goto skip_ns;
-               } else {
-                   uri = xmlParseURI((const char *) URL);
-                   if (uri == NULL) {
-                       xmlNsErr(ctxt, XML_WAR_NS_URI,
-                            "xmlns:%s: '%s' is not a valid URI\n",
-                                          attname, URL, NULL);
-                   } else {
-                       if ((ctxt->pedantic) && (uri->scheme == NULL)) {
-                           xmlNsWarn(ctxt, XML_WAR_NS_URI_RELATIVE,
-                                     "xmlns:%s: URI %s is not absolute\n",
-                                     attname, URL, NULL);
-                       }
-                       xmlFreeURI(uri);
-                   }
-               }
-
-               /*
-                * check that it's not a defined namespace
-                */
-               for (j = 1;j <= nbNs;j++)
-                   if (ctxt->nsTab[ctxt->nsNr - 2 * j] == attname)
-                       break;
-               if (j <= nbNs)
-                   xmlErrAttributeDup(ctxt, aprefix, attname);
-               else
-                   if (nsPush(ctxt, attname, URL) > 0) nbNs++;
-skip_ns:
-               if ((attvalue != NULL) && (alloc != 0)) {
-                   xmlFree(attvalue);
-                   attvalue = NULL;
-               }
-               if ((RAW == '>') || (((RAW == '/') && (NXT(1) == '>'))))
-                   break;
-               if (!IS_BLANK_CH(RAW)) {
-                   xmlFatalErrMsg(ctxt, XML_ERR_SPACE_REQUIRED,
-                                  "attributes construct error\n");
-                   break;
-               }
-               SKIP_BLANKS;
-               if ((ctxt->input->base != base) || (inputNr != ctxt->inputNr))
-                   goto base_changed;
-               continue;
-           }
+                    if (attname != ctxt->str_xml) {
+                        xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                     "xml namespace URI cannot be the default namespace\n",
+                                 NULL, NULL, NULL);
+                    }
+                    goto next_attr;
+                }
+                if ((len == 29) &&
+                    (xmlStrEqual(URL,
+                             BAD_CAST "http://www.w3.org/2000/xmlns/";))) {
+                    xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                         "reuse of the xmlns namespace name is forbidden\n",
+                             NULL, NULL, NULL);
+                    goto next_attr;
+                }
+            }
+            /*
+             * check that it's not a defined namespace
+             */
+            for (j = 1;j <= nbNs;j++)
+                if (ctxt->nsTab[ctxt->nsNr - 2 * j] == NULL)
+                    break;
+            if (j <= nbNs)
+                xmlErrAttributeDup(ctxt, NULL, attname);
+            else
+                if (nsPush(ctxt, NULL, URL) > 0) nbNs++;
+
+        } else if (aprefix == ctxt->str_xmlns) {
+            const xmlChar *URL = xmlDictLookup(ctxt->dict, attvalue, len);
+            xmlURIPtr uri;
+
+            if (attname == ctxt->str_xml) {
+                if (URL != ctxt->str_xml_ns) {
+                    xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                             "xml namespace prefix mapped to wrong URI\n",
+                             NULL, NULL, NULL);
+                }
+                /*
+                 * Do not keep a namespace definition node
+                 */
+                goto next_attr;
+            }
+            if (URL == ctxt->str_xml_ns) {
+                if (attname != ctxt->str_xml) {
+                    xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                             "xml namespace URI mapped to wrong prefix\n",
+                             NULL, NULL, NULL);
+                }
+                goto next_attr;
+            }
+            if (attname == ctxt->str_xmlns) {
+                xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                         "redefinition of the xmlns prefix is forbidden\n",
+                         NULL, NULL, NULL);
+                goto next_attr;
+            }
+            if ((len == 29) &&
+                (xmlStrEqual(URL,
+                             BAD_CAST "http://www.w3.org/2000/xmlns/";))) {
+                xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                         "reuse of the xmlns namespace name is forbidden\n",
+                         NULL, NULL, NULL);
+                goto next_attr;
+            }
+            if ((URL == NULL) || (URL[0] == 0)) {
+                xmlNsErr(ctxt, XML_NS_ERR_XML_NAMESPACE,
+                         "xmlns:%s: Empty XML namespace is not allowed\n",
+                              attname, NULL, NULL);
+                goto next_attr;
+            } else {
+                uri = xmlParseURI((const char *) URL);
+                if (uri == NULL) {
+                    xmlNsErr(ctxt, XML_WAR_NS_URI,
+                         "xmlns:%s: '%s' is not a valid URI\n",
+                                       attname, URL, NULL);
+                } else {
+                    if ((ctxt->pedantic) && (uri->scheme == NULL)) {
+                        xmlNsWarn(ctxt, XML_WAR_NS_URI_RELATIVE,
+                                  "xmlns:%s: URI %s is not absolute\n",
+                                  attname, URL, NULL);
+                    }
+                    xmlFreeURI(uri);
+                }
+            }
 
-           /*
-            * Add the pair to atts
-            */
-           if ((atts == NULL) || (nbatts + 5 > maxatts)) {
-               if (xmlCtxtGrowAttrs(ctxt, nbatts + 5) < 0) {
-                   if (attvalue[len] == 0)
-                       xmlFree(attvalue);
-                   goto failed;
-               }
-               maxatts = ctxt->maxatts;
-               atts = ctxt->atts;
-           }
-           ctxt->attallocs[nratts++] = alloc;
-           atts[nbatts++] = attname;
-           atts[nbatts++] = aprefix;
-           atts[nbatts++] = NULL; /* the URI will be fetched later */
-           atts[nbatts++] = attvalue;
-           attvalue += len;
-           atts[nbatts++] = attvalue;
-           /*
-            * tag if some deallocation is needed
-            */
-           if (alloc != 0) attval = 1;
-       } else {
-           if ((attvalue != NULL) && (attvalue[len] == 0))
-               xmlFree(attvalue);
-       }
+            /*
+             * check that it's not a defined namespace
+             */
+            for (j = 1;j <= nbNs;j++)
+                if (ctxt->nsTab[ctxt->nsNr - 2 * j] == attname)
+                    break;
+            if (j <= nbNs)
+                xmlErrAttributeDup(ctxt, aprefix, attname);
+            else
+                if (nsPush(ctxt, attname, URL) > 0) nbNs++;
+
+        } else {
+            /*
+             * Add the pair to atts
+             */
+            if ((atts == NULL) || (nbatts + 5 > maxatts)) {
+                if (xmlCtxtGrowAttrs(ctxt, nbatts + 5) < 0) {
+                    goto next_attr;
+                }
+                maxatts = ctxt->maxatts;
+                atts = ctxt->atts;
+            }
+            ctxt->attallocs[nratts++] = alloc;
+            atts[nbatts++] = attname;
+            atts[nbatts++] = aprefix;
+            atts[nbatts++] = NULL; /* the URI will be fetched later */
+            atts[nbatts++] = attvalue;
+            attvalue += len;
+            atts[nbatts++] = attvalue;
+            /*
+             * tag if some deallocation is needed
+             */
+            if (alloc != 0) attval = 1;
+            attvalue = NULL; /* moved into atts */
+        }
 
-failed:
+next_attr:
+        if ((attvalue != NULL) && (alloc != 0)) {
+            xmlFree(attvalue);
+            attvalue = NULL;
+        }
 
        GROW
         if (ctxt->instate == XML_PARSER_EOF)