[libxml2] Fix memory leaks of encoding handlers in xmlsave.c

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 42942066e1f6422e26cd162a6014b19ac215083f
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Mon Nov 11 13:49:11 2019 +0100

    Fix memory leaks of encoding handlers in xmlsave.c
    
    Fix leak of iconv/ICU encoding handler in xmlSaveToBuffer.
    
    Fix leaks of iconv/ICU encoding handlers in xmlSaveTo* error paths.
    
    Closes #127.

 xmlsave.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)
---
diff --git a/xmlsave.c b/xmlsave.c
index fa009153..7158c26b 100644
--- a/xmlsave.c
+++ b/xmlsave.c
@@ -1802,6 +1802,7 @@ xmlSaveToFd(int fd, const char *encoding, int options)
     if (ret == NULL) return(NULL);
     ret->buf = xmlOutputBufferCreateFd(fd, ret->handler);
     if (ret->buf == NULL) {
+        xmlCharEncCloseFunc(ret->handler);
        xmlFreeSaveCtxt(ret);
        return(NULL);
     }
@@ -1831,6 +1832,7 @@ xmlSaveToFilename(const char *filename, const char *encoding, int options)
     ret->buf = xmlOutputBufferCreateFilename(filename, ret->handler,
                                              compression);
     if (ret->buf == NULL) {
+        xmlCharEncCloseFunc(ret->handler);
        xmlFreeSaveCtxt(ret);
        return(NULL);
     }
@@ -1853,28 +1855,15 @@ xmlSaveCtxtPtr
 xmlSaveToBuffer(xmlBufferPtr buffer, const char *encoding, int options)
 {
     xmlSaveCtxtPtr ret;
-    xmlOutputBufferPtr out_buff;
-    xmlCharEncodingHandlerPtr handler;
 
     ret = xmlNewSaveCtxt(encoding, options);
     if (ret == NULL) return(NULL);
-
-    if (encoding != NULL) {
-        handler = xmlFindCharEncodingHandler(encoding);
-        if (handler == NULL) {
-            xmlFree(ret);
-            return(NULL);
-        }
-    } else
-        handler = NULL;
-    out_buff = xmlOutputBufferCreateBuffer(buffer, handler);
-    if (out_buff == NULL) {
-        xmlFree(ret);
-        if (handler) xmlCharEncCloseFunc(handler);
-        return(NULL);
+    ret->buf = xmlOutputBufferCreateBuffer(buffer, ret->handler);
+    if (ret->buf == NULL) {
+        xmlCharEncCloseFunc(ret->handler);
+       xmlFreeSaveCtxt(ret);
+       return(NULL);
     }
-
-    ret->buf = out_buff;
     return(ret);
 }
 
@@ -1902,6 +1891,7 @@ xmlSaveToIO(xmlOutputWriteCallback iowrite,
     if (ret == NULL) return(NULL);
     ret->buf = xmlOutputBufferCreateIO(iowrite, ioclose, ioctx, ret->handler);
     if (ret->buf == NULL) {
+        xmlCharEncCloseFunc(ret->handler);
        xmlFreeSaveCtxt(ret);
        return(NULL);
     }