.

wcfs/internal/wcfs_misc.cpp

@@ -36,6 +36,7 @@ using namespace golang;
 namespace io {
 
 const error EOF_                = fmt::errorf("EOF");
+const error ErrUnexpectedEOF    = fmt::errorf("unexpected EOF");
 
 }   // io::
 

wcfs/internal/wcfs_misc.h

@@ -51,6 +51,7 @@ struct error {
 namespace io {
 
 extern const error EOF_;
+extern const error ErrUnexpectedEOF;
 
 
 }   // io::

wcfs/internal/wcfs_virtmem.cpp

@@ -209,6 +209,7 @@ public:
 private:
     void _closeTX();
     error _serveRX(IContext *ctx);
+    tuple<string, error> _readline();
     error _send(StreamID stream, const string &msg);
     error _write(const string &pkt);
     tuple<chan<rxPkt>, error> _sendReq(IContext *ctx, const string &req);
@@ -467,14 +468,19 @@ error WatchLink::_serveRX(IContext *ctx) {    // XXX error -> where ?
         }
     });
 
+    string l;
+    error  err;
+
     while (1) {
         // NOTE: .close() makes sure .f.read*() will wake up
-        l = wlink._f.readline()
-        printf("C: watch  : rx: %r" % l);
-        if (len(l) == 0) {      // peer closed its tx
+        tie(l, err) = wlink._readline();
+        if (err == io::EOF_) {  // peer closed its tx
+            // XXX what happens with other errors?
             wlink._rx_eof.close();
-            break;
         }
+        if (err != nil)
+            return err;
+        printf("C: watch  : rx: %s", l.c_str());
 
         // <stream> ... \n
         stream, msg = l.split(' ', 1)
@@ -618,6 +624,35 @@ tuple</*rxq*/chan<rxPkt>, error> WatchLink::_sendReq(IContext *ctx, const string
     return make_tuple(rxq, err);
 }
 
+// _readline reads next raw line sent from wcfs.
+tuple<string, error> WatchLink::_readline() {
+    WatchLink& wlink = *this;
+    char buf[128];
+
+    pos = 0;    // XXX naming
+    while (1) {
+        nl = wlink._rxbuf.find('\n', pos);
+        if (nl != string::npos) {
+            line = string(wlink._rxbuf, 0, nl+1);
+            wlink._rxbuf = string(wlink._rxbuf, nl+1);
+            return make_tuple(line, nil);
+        }
+        pos = wlink._rxbuf.length();
+
+        tie(n, err) = wlink._f.read(buf, sizeof(buf));
+        if (n > 0) {
+            // XXX limit line length to avoid DoS
+            wlink._rxbuf += string(buf, n);
+            continue;
+        }
+        if (err == nil)
+            panic("read returned (0, nil)");
+        if (err == io::EOF_ && wlink._rxbuf.length() != 0)
+            err = io::ErrUnexpectedEOF;
+        return make_tuple("", err);
+    }
+}
+
 // ---- WCFS raw file access ----
 
 // _path returns path for object on wcfs.