db/upnp: make several methods "const"

src/db/UpnpDatabasePlugin.cxx

@@ -103,7 +103,7 @@ protected:
 	bool Configure(const config_param &param, Error &error);
 
 private:
-	bool VisitServer(ContentDirectoryService &server,
+	bool VisitServer(const ContentDirectoryService &server,
 			 const std::list<std::string> &vpath,
 			 const DatabaseSelection &selection,
 			 VisitDirectory visit_directory,
@@ -115,19 +115,19 @@ private:
 	 * Run an UPnP search according to MPD parameters, and
 	 * visit_song the results.
 	 */
-	bool SearchSongs(ContentDirectoryService &server,
+	bool SearchSongs(const ContentDirectoryService &server,
 			 const char *objid,
 			 const DatabaseSelection &selection,
 			 VisitSong visit_song,
 			 Error &error) const;
 
-	bool SearchSongs(ContentDirectoryService &server,
+	bool SearchSongs(const ContentDirectoryService &server,
 			 const char *objid,
 			 const DatabaseSelection &selection,
 			 UPnPDirContent& dirbuf,
 			 Error &error) const;
 
-	bool Namei(ContentDirectoryService &server,
+	bool Namei(const ContentDirectoryService &server,
 		   const std::list<std::string> &vpath,
 		   UPnPDirObject &dirent,
 		   Error &error) const;
@@ -135,7 +135,7 @@ private:
 	/**
 	 * Take server and objid, return metadata.
 	 */
-	bool ReadNode(ContentDirectoryService &server,
+	bool ReadNode(const ContentDirectoryService &server,
 		      const char *objid, UPnPDirObject& dirent,
 		      Error &error) const;
 
@@ -144,7 +144,7 @@ private:
 	 * except easier cause our inodes have a parent id. Not used
 	 * any more actually (see comments in SearchSongs).
 	 */
-	bool BuildPath(ContentDirectoryService &server,
+	bool BuildPath(const ContentDirectoryService &server,
 		       const UPnPDirObject& dirent, std::string &idpath,
 		       Error &error) const;
 };
@@ -266,7 +266,7 @@ dquote(std::string &out, const char *in)
 // Run an UPnP search, according to MPD parameters. Return results as
 // UPnP items
 bool
-UpnpDatabase::SearchSongs(ContentDirectoryService &server,
+UpnpDatabase::SearchSongs(const ContentDirectoryService &server,
 			  const char *objid,
 			  const DatabaseSelection &selection,
 			  UPnPDirContent &dirbuf,
@@ -381,7 +381,7 @@ songPath(const std::string &servername,
 }
 
 bool
-UpnpDatabase::SearchSongs(ContentDirectoryService &server,
+UpnpDatabase::SearchSongs(const ContentDirectoryService &server,
 			  const char *objid,
 			  const DatabaseSelection &selection,
 			  VisitSong visit_song,
@@ -426,7 +426,7 @@ UpnpDatabase::SearchSongs(ContentDirectoryService &server,
 }
 
 bool
-UpnpDatabase::ReadNode(ContentDirectoryService &server,
+UpnpDatabase::ReadNode(const ContentDirectoryService &server,
 		       const char *objid, UPnPDirObject &dirent,
 		       Error &error) const
 {
@@ -445,7 +445,7 @@ UpnpDatabase::ReadNode(ContentDirectoryService &server,
 }
 
 bool
-UpnpDatabase::BuildPath(ContentDirectoryService &server,
+UpnpDatabase::BuildPath(const ContentDirectoryService &server,
 			const UPnPDirObject& idirent,
 			std::string &path,
 			Error &error) const
@@ -472,7 +472,7 @@ UpnpDatabase::BuildPath(ContentDirectoryService &server,
 
 // Take server and internal title pathname and return objid and metadata.
 bool
-UpnpDatabase::Namei(ContentDirectoryService &server,
+UpnpDatabase::Namei(const ContentDirectoryService &server,
 		    const std::list<std::string> &vpath,
 		    UPnPDirObject &odirent,
 		    Error &error) const
@@ -521,7 +521,7 @@ UpnpDatabase::Namei(ContentDirectoryService &server,
 // vpath is a parsed and writeable version of selection.uri. There is
 // really just one path parameter.
 bool
-UpnpDatabase::VisitServer(ContentDirectoryService &server,
+UpnpDatabase::VisitServer(const ContentDirectoryService &server,
 			  const std::list<std::string> &vpath,
 			  const DatabaseSelection &selection,
 			  VisitDirectory visit_directory,

src/db/upnp/ContentDirectoryService.cxx

@@ -63,7 +63,7 @@ ContentDirectoryService::readDirSlice(UpnpClient_Handle hdl,
 				      const char *objectId, unsigned offset,
 				      unsigned count, UPnPDirContent &dirbuf,
 				      unsigned &didreadp, unsigned &totalp,
-				      Error &error)
+				      Error &error) const
 {
 	// Create request
 	char ofbuf[100], cntbuf[100];
@@ -112,7 +112,7 @@ bool
 ContentDirectoryService::readDir(UpnpClient_Handle handle,
 				 const char *objectId,
 				 UPnPDirContent &dirbuf,
-				 Error &error)
+				 Error &error) const
 {
 	unsigned offset = 0, total = -1, count;
 
@@ -132,7 +132,7 @@ ContentDirectoryService::search(UpnpClient_Handle hdl,
 				const char *objectId,
 				const char *ss,
 				UPnPDirContent &dirbuf,
-				Error &error)
+				Error &error) const
 {
 	unsigned offset = 0, total = -1, count;
 
@@ -189,7 +189,7 @@ ContentDirectoryService::search(UpnpClient_Handle hdl,
 bool
 ContentDirectoryService::getSearchCapabilities(UpnpClient_Handle hdl,
 					       std::list<std::string> &result,
-					       Error &error)
+					       Error &error) const
 {
 	assert(result.empty());
 
@@ -234,7 +234,7 @@ bool
 ContentDirectoryService::getMetadata(UpnpClient_Handle hdl,
 				     const char *objectId,
 				     UPnPDirContent &dirbuf,
-				     Error &error)
+				     Error &error) const
 {
 	// Create request
 	IXML_Document *request =

src/db/upnp/ContentDirectoryService.hxx

@@ -75,13 +75,13 @@ public:
 	 */
 	bool readDir(UpnpClient_Handle handle,
 		     const char *objectId, UPnPDirContent &dirbuf,
-		     Error &error);
+		     Error &error) const;
 
 	bool readDirSlice(UpnpClient_Handle handle,
 			  const char *objectId, unsigned offset,
 			  unsigned count, UPnPDirContent& dirbuf,
 			  unsigned &didread, unsigned &total,
-			  Error &error);
+			  Error &error) const;
 
 	/** Search the content directory service.
 	 *
@@ -96,7 +96,7 @@ public:
 	bool search(UpnpClient_Handle handle,
 		    const char *objectId, const char *searchstring,
 		    UPnPDirContent &dirbuf,
-		    Error &error);
+		    Error &error) const;
 
 	/** Read metadata for a given node.
 	 *
@@ -106,7 +106,7 @@ public:
 	 */
 	bool getMetadata(UpnpClient_Handle handle,
 			 const char *objectId, UPnPDirContent &dirbuf,
-			 Error &error);
+			 Error &error) const;
 
 	/** Retrieve search capabilities
 	 *
@@ -115,7 +115,7 @@ public:
 	 */
 	bool getSearchCapabilities(UpnpClient_Handle handle,
 				   std::list<std::string> &result,
-				   Error &error);
+				   Error &error) const;
 
 	/** Retrieve the "friendly name" for this server, useful for display. */
 	const char *getFriendlyName() const {