.

wcfs/internal/wcfs_misc.cpp

@@ -199,6 +199,10 @@ error errorf(const char *format, ...) {
 // strings::
 namespace strings {
 
+bool has_prefix(const string &s, const string &prefix) {
+    return s.compare(0, prefix.size(), prefix);
+}
+
 vector<string> split(const string &s, char sep) {
     vector<string> r;
     int psep_prev=-1, psep;

wcfs/internal/wcfs_misc.h

@@ -143,6 +143,7 @@ error  errorf (const char *format, ...)
 //  strings::
 namespace strings {
 
+bool has_prefix(const string &s, const string &prefix);
 vector<string> split(const string &s, char sep);
 
 }   // strings::

wcfs/internal/wcfs_virtmem.cpp

@@ -663,7 +663,7 @@ tuple</*rxq*/chan<rxPkt>, error> WatchLink::_sendReq(IContext *ctx, const string
 }
 
 // recvReq receives client <- server request.
-error WatchLink::recvReq(IContext *ctx, PinReq *rx) {
+error WatchLink::recvReq(IContext *ctx, PinReq *prx) {
     WatchLink& wlink = *this;
 
     rxPkt pkt;
@@ -680,18 +680,27 @@ error WatchLink::recvReq(IContext *ctx, PinReq *rx) {
         return rx
 #endif
 
-    rx->stream = pkt.stream;
     pkt.to_string();
-    stream, msg = rx
-    // XXX -> _parsePinReq
-    return PinReq(wlink, stream, msg)
+    err = _parsePinReq(prx, &pkt);
+    return err;
 }
 
 // _parsePinReq parses message into PinReq according to wcfs invalidation protocol.
-error _parsePinReq(PinReq *out, const string &msg) {
+error _parsePinReq(PinReq *pin, const rxPkt *pkt) {
+    // XXX err ctx "bad pin"
+    pin->stream = pkt->stream;
+
     // pin <foid>) #<blk> @<at>
-    msgv = strings::split(msg, ' ');
-    if 
+    if (!strings::has_prefix(msg, "pin "))
+        return fmt::errorf("not a pin request");    // XXX +msg?
+
+    argv = strings::split(msg.substr(4), ' ');
+    if (msgv.len() != 3)
+        return fmt::errorf("expected 3 arguments, got %d", msgv.len());
+
+    // XXX
+
+    return nil;
 }
 
 // _readline reads next raw line sent from wcfs.