Use accessor functions to manipulate xmlOutputBuffer

This is a fix to prepare the xmlj_io.c file of gnu classpath to a coming
API change in libxml2.

Basically, we were previously accessing fields inside the
xmlOutputBuffer struct of libxml2.  In a coming version of libxml2,
that won't be possible anymore.  Client code will have to use accessor
functions instead.  For the gory details, there is an interestin note
of Daniel Veillard (author of libxml2) at
https://mail.gnome.org/archives/desktop-devel-list/2012-August/msg00007.html.

This patch defines too accessor macros that, depending on the version
of libxml2 we are using will either access the fields of
xmlOutputBuffer directly, or use the new accessor function.

Tested on x86_64-unknown-linux-gnu against trunk.

libjava/classpath/

	* native/jni/xmlj/xmlj_io.c (GET_XML_OUTPUT_BUFFER_CONTENT)
	(GET_XML_OUTPUT_BUFFER_SIZE): New macros.
	(xmljOutputWriteCallback): Use them.

From-SVN: r190249

libjava/classpath/ChangeLog

+2012-08-09  Dodji Seketeli  <dodji@redhat.com>
+
+	Use accessor functions to manipulate xmlOutputBuffer
+	* native/jni/xmlj/xmlj_io.c (GET_XML_OUTPUT_BUFFER_CONTENT)
+    	(GET_XML_OUTPUT_BUFFER_SIZE): New macros.
+    	(xmljOutputWriteCallback): Use them.
+
 2012-03-08  Andrew John Hughes  <ahughes@redhat.com>
 
 	* NEWS: Set correct release date.

libjava/classpath/native/jni/xmlj/xmlj_io.c

@@ -102,6 +102,19 @@ xmljFreeOutputStreamContext (OutputStreamContext * outContext);
 xmlCharEncoding
 xmljDetectCharEncoding (JNIEnv * env, jbyteArray buffer);
 
+
+#ifdef LIBXML2_NEW_BUFFER
+#define GET_XML_OUTPUT_BUFFER_CONTENT(buf) (gchar *) \
+  (char *) xmlOutputBufferGetContent(buf)
+#define GET_XML_OUTPUT_BUFFER_SIZE(buf) \
+  xmlOutputBufferGetSize(buf)
+#else
+#define GET_XML_OUTPUT_BUFFER_CONTENT(buf) \
+ (buf)->buffer->content
+#define GET_XML_OUTPUT_BUFFER_SIZE(buf) \
+  (buf)->buffer->use
+#endif
+
 int
 xmljOutputWriteCallback (void *context, const char *buffer, int len)
 {
@@ -752,9 +765,10 @@ xmljLoadExternalEntity (const char *URL, const char *ID,
       inputStream->directory = NULL;
       inputStream->buf = inputBuffer;
 
-      inputStream->base = inputStream->buf->buffer->content;
-      inputStream->cur = inputStream->buf->buffer->content;
-      inputStream->end = &inputStream->base[inputStream->buf->buffer->use];
+      inputStream->base = GET_XML_OUTPUT_BUFFER_CONTENT (inputStream->buf);
+      inputStream->cur = GET_XML_OUTPUT_BUFFER_CONTENT (inputStream->buf);
+      inputStream->end =
+      &inputStream->base[GET_XML_OUTPUT_BUFFER_SIZE (inputStream->buf)];
       if ((ctxt->directory == NULL) && (inputStream->directory != NULL))
         ctxt->directory =
           (char *) xmlStrdup ((const xmlChar *) inputStream->directory);