Make ServerPrivateAccessor::Prefix static

src/brpc/builtin/prometheus_metrics_service.cpp

@@ -190,7 +190,7 @@ void PrometheusMetricsService::default_method(::google::protobuf::RpcController*
 
 int DumpPrometheusMetricsToIOBuf(butil::IOBuf* output) {
     butil::IOBufBuilder os;
-    PrometheusMetricsDumper dumper(&os, brpc::ServerPrivateAccessor(NULL).Prefix());
+    PrometheusMetricsDumper dumper(&os, brpc::ServerPrivateAccessor::Prefix());
     const int ndump = bvar::Variable::dump_exposed(&dumper, NULL);
     if (ndump < 0) {
         return -1;

src/brpc/details/server_private_accessor.h

@@ -30,6 +30,7 @@ namespace brpc {
 class ServerPrivateAccessor {
 public:
     explicit ServerPrivateAccessor(const Server* svr) {
+        CHECK(svr);
         _server = svr;
     }
 
@@ -97,7 +98,7 @@ public:
     RestfulMap* global_restful_map() const
     { return _server->_global_restful_map; }
 
-    std::string Prefix() const { return Server::Prefix(); }
+    static std::string Prefix() { return Server::Prefix(); }
 
 private:
     const Server* _server;