.

wcfs/client/wcfs.cpp

@@ -54,8 +54,8 @@
 // core element in handling WCFS isolation protocol, is effectively invoked
 // synchronously from other threads via messages coming through wcfs server.
 // For example Conn.resync sends watch request to wcfs and waits for the
-// answer. Wcfs server, in turn, sends corresponding pin messages to the pinner
-// and _waits_ for the answere before answering to resync:
+// answer. Wcfs server, in turn, might send corresponding pin messages to the
+// pinner and _wait_ for the answere before answering to resync:
 //
 //        - - - - - -
 //       |       .···|·····.        ---->   = request
@@ -139,7 +139,7 @@ pair<Conn, error> WCFS::connect(zodb::Tid at) {
     // and stats head/f to get f.headfsize _before_ that.
     // -> just wait here.
     // XXX atMu.RLock ?
-    err = wconn._headWait(at);
+    err = wconn->_headWait(at);
     if (err != nil) {
         // XXX bring conn down - stop pinner
         return make_pair(nil, E(err));
@@ -149,6 +149,14 @@ pair<Conn, error> WCFS::connect(zodb::Tid at) {
 }
 
 
+// _headWait waits till wcfs/head/at becomes ≥ at.
+//
+// XXX locks condition?
+error _Conn::_headWait(zodb::Tid at) {  // XXX +ctx ?
+    // FIXME implement
+    return nil;
+}
+
 static global<error> errConnClosed = errors::New("connection closed");
 
 // close releases resources associated with wconn.

wcfs/client/wcfs.h

@@ -208,6 +208,7 @@ private:
     error __pinner(context::Context ctx);
     error _pin1(PinReq *req);
     error __pin1(PinReq *req);
+    error _headWait(zodb::Tid at);
 };
 
 // FileH represent isolated file view under Conn.