Make gmediarender compile with version libupnp 1.6.7 ... 1.6.16.

With version 1.6.7 and above, the UPNP library maintainers made a questionable
API choice to register the webserver callbacks one-by-one, instead of having a
struct with the callbacks which is certainly a better and 'typical' C API
choice. They removed the UpnpVirtualDirCallbacks in the course of that.
Because it breaks code, it has been reverted in version 1.6.16
(see http://sourceforge.net/p/pupnp/bugs/29/ ), but we essentially have a
broken version between 1.6.7 ... 1.6.16.

Assuming that they will go on with this broken idea and eventually remove
the support for the VirtualDirCallbacks in new major versions, we now
register the callbacks separately when upnp-version >= 1.6.7

src/upnp_device.c

@@ -424,12 +424,8 @@ static gboolean initialize_device(struct upnp_device_descriptor *device_def,
 		return FALSE;
 	}
 
-	rc = UpnpSetVirtualDirCallbacks(&virtual_dir_callbacks);
-	if (UPNP_E_SUCCESS != rc) {
-		Log_error("upnp", "UpnpSetVirtualDirCallbacks() Error: %s (%d)",
-			  UpnpGetErrorMessage(rc), rc);
-		return FALSE;
-	}
+	if (!webserver_register_callbacks())
+	  return FALSE;
 
 	rc = UpnpAddVirtualDir("/upnp");
 	if (UPNP_E_SUCCESS != rc) {

src/webserver.c

@@ -37,6 +37,7 @@
 #include <assert.h>
 
 #include <upnp/upnp.h>
+#include <upnp/upnptools.h>  // UpnpGetErrorMessage
 #include <upnp/ithread.h>
 
 #include "logging.h"
@@ -247,11 +248,46 @@ static int webserver_close(UpnpWebFileHandle fh)
 	return 0;
 }
 
-struct UpnpVirtualDirCallbacks virtual_dir_callbacks = {
+#if (UPNP_VERSION < 10607)
+// Older versions had a nice struct to register callbacks, just as you would
+// expect from a proper C API
+static struct UpnpVirtualDirCallbacks virtual_dir_callbacks = {
 	webserver_get_info,
 	webserver_open,
 	webserver_read,
 	webserver_write,
 	webserver_seek,
 	webserver_close
 };
+
+gboolean webserver_register_callbacks(void) {
+  int rc = UpnpSetVirtualDirCallbacks(&virtual_dir_callbacks);
+  if (UPNP_E_SUCCESS != rc) {
+    Log_error("webserver", "UpnpSetVirtualDirCallbacks() Error: %s (%d)",
+	      UpnpGetErrorMessage(rc), rc);
+    return FALSE;
+  }
+  return TRUE;
+}
+#else
+// With version 1.6.7 and above, the UPNP library maintainers made a questionable
+// API choice to register the callbacks one-by-one, instead of having a
+// struct with the callbacks which is certainly a better and 'typical' C API
+// choice. They removed the UpnpVirtualDirCallbacks in the course of that.
+// Because it breaks code, it has been reverted in version 1.6.16
+// (see http://sourceforge.net/p/pupnp/bugs/29/ ), but we essentially have a
+// broken version between 1.6.7 ... 1.6.16.
+// Assuming that they will go on with this broken idea and eventually remove
+// the support for the VirtualDirCallbacks in new major versions, we use the
+// newer (may I emphasize: questionable) API to register the callbacks.
+gboolean webserver_register_callbacks(void) {
+  gboolean result =
+    (UpnpVirtualDir_set_GetInfoCallback(webserver_get_info) == UPNP_E_SUCCESS
+     && UpnpVirtualDir_set_OpenCallback(webserver_open) == UPNP_E_SUCCESS
+     && UpnpVirtualDir_set_ReadCallback(webserver_read) == UPNP_E_SUCCESS
+     && UpnpVirtualDir_set_WriteCallback(webserver_write) == UPNP_E_SUCCESS
+     && UpnpVirtualDir_set_SeekCallback(webserver_seek) == UPNP_E_SUCCESS
+     && UpnpVirtualDir_set_CloseCallback(webserver_close) == UPNP_E_SUCCESS);
+  return result;
+}
+#endif

src/webserver.h

@@ -24,7 +24,10 @@
 #ifndef _WEBSERVER_H
 #define _WEBSERVER_H
 
-extern struct UpnpVirtualDirCallbacks virtual_dir_callbacks;
+#include <glib.h>
+
+// Start the webserver with the registered files.
+gboolean webserver_register_callbacks(void);
 
 int webserver_register_buf(const char *path, const char *contents,
                            const char *content_type);