[libxml2] 582913 Fix htmlSetMetaEncoding() to be nicer

[Daniel Veillard <veillard src gnome org>]

commit 8d7c1b7ab296ea2e8c8d18d7b8f3d24e0963f8ff
Author: Daniel Veillard <veillard redhat com>
Date:   Wed Aug 12 23:03:23 2009 +0200

    582913 Fix htmlSetMetaEncoding() to be nicer
    
    * HTMLtree.c: htmlSetMetaEncoding should not destroy existing meta
      encoding elements, plus it should not change things at all if the
      encoding is the same. Also fixed htmlSaveFileFormat() to ask for
      change if outputing to UTF-8.

 HTMLtree.c |   71 ++++++++++++++++++++++++++++++++---------------------------
 1 files changed, 38 insertions(+), 33 deletions(-)
---
diff --git a/HTMLtree.c b/HTMLtree.c
index d55ff28..b508583 100644
--- a/HTMLtree.c
+++ b/HTMLtree.c
@@ -160,8 +160,8 @@ found_content:
  */
 int
 htmlSetMetaEncoding(htmlDocPtr doc, const xmlChar *encoding) {
-    htmlNodePtr cur, meta;
-    const xmlChar *content;
+    htmlNodePtr cur, meta = NULL, head = NULL;
+    const xmlChar *content = NULL;
     char newcontent[100];
 
 
@@ -205,39 +205,24 @@ htmlSetMetaEncoding(htmlDocPtr doc, const xmlChar *encoding) {
 	if ((cur->type == XML_ELEMENT_NODE) && (cur->name != NULL)) {
 	    if (xmlStrcasecmp(cur->name, BAD_CAST"head") == 0)
 		break;
-	    if (xmlStrcasecmp(cur->name, BAD_CAST"meta") == 0)
+	    if (xmlStrcasecmp(cur->name, BAD_CAST"meta") == 0) {
+                head = cur->parent;
 		goto found_meta;
+            }
 	}
 	cur = cur->next;
     }
     if (cur == NULL)
 	return(-1);
 found_head:
-    if (cur->children == NULL) {
-	if (encoding == NULL)
-	    return(0);
-	meta = xmlNewDocNode(doc, NULL, BAD_CAST"meta", NULL);
-	xmlAddChild(cur, meta);
-	xmlNewProp(meta, BAD_CAST"http-equiv", BAD_CAST"Content-Type");
-	xmlNewProp(meta, BAD_CAST"content", BAD_CAST newcontent);
-	return(0);
-    }
+    head = cur;
+    if (cur->children == NULL)
+        goto create;
     cur = cur->children;
 
 found_meta:
-    if (encoding != NULL) {
-	/*
-	 * Create a new Meta element with the right attributes
-	 */
-
-	meta = xmlNewDocNode(doc, NULL, BAD_CAST"meta", NULL);
-	xmlAddPrevSibling(cur, meta);
-	xmlNewProp(meta, BAD_CAST"http-equiv", BAD_CAST"Content-Type");
-	xmlNewProp(meta, BAD_CAST"content", BAD_CAST newcontent);
-    }
-
     /*
-     * Search and destroy all the remaining the meta elements carrying
+     * Search and update all the remaining the meta elements carrying
      * encoding informations
      */
     while (cur != NULL) {
@@ -257,11 +242,11 @@ found_meta:
 			if ((!xmlStrcasecmp(attr->name, BAD_CAST"http-equiv"))
 			 && (!xmlStrcasecmp(value, BAD_CAST"Content-Type")))
 			    http = 1;
-			else 
+			else
                         {
                            if ((value != NULL) && 
-				(!xmlStrcasecmp(attr->name, BAD_CAST"content")))
-			      content = value;
+                               (!xmlStrcasecmp(attr->name, BAD_CAST"content")))
+			       content = value;
                         }
 		        if ((http != 0) && (content != NULL))
 			    break;
@@ -270,16 +255,36 @@ found_meta:
 		}
 		if ((http != 0) && (content != NULL)) {
 		    meta = cur;
-		    cur = cur->next;
-		    xmlUnlinkNode(meta);
-                    xmlFreeNode(meta);
-		    continue;
+		    break;
 		}
 
 	    }
 	}
 	cur = cur->next;
     }
+create:
+    if (meta == NULL) {
+        if ((encoding != NULL) && (head != NULL)) {
+            /*
+             * Create a new Meta element with the right attributes
+             */
+
+            meta = xmlNewDocNode(doc, NULL, BAD_CAST"meta", NULL);
+            if (head->children == NULL)
+                xmlAddChild(head, meta);
+            else
+                xmlAddPrevSibling(head->children, meta);
+            xmlNewProp(meta, BAD_CAST"http-equiv", BAD_CAST"Content-Type");
+            xmlNewProp(meta, BAD_CAST"content", BAD_CAST newcontent);
+        }
+    } else {
+        /* change the document only if there is a real encoding change */
+        if (xmlStrcasestr(content, encoding) == NULL) {
+            xmlSetProp(meta, BAD_CAST"content", BAD_CAST newcontent);
+        }
+    }
+
+
     return(0);
 }
 
@@ -1159,7 +1164,7 @@ htmlSaveFileFormat(const char *filename, xmlDocPtr cur,
 
     if ((cur == NULL) || (filename == NULL))
         return(-1);
-       
+
     xmlInitParser();
 
     if (encoding != NULL) {
@@ -1177,8 +1182,8 @@ htmlSaveFileFormat(const char *filename, xmlDocPtr cur,
 	    handler = xmlFindCharEncodingHandler(encoding);
 	    if (handler == NULL)
 		return(-1);
-            htmlSetMetaEncoding(cur, (const xmlChar *) encoding);
 	}
+        htmlSetMetaEncoding(cur, (const xmlChar *) encoding);
     } else {
 	htmlSetMetaEncoding(cur, (const xmlChar *) "UTF-8");
     }