.

wcfs/internal/wcfs.h

@@ -33,8 +33,8 @@ using std::pair;
 
 #include "wcfs_misc.h"
 
-struct Conn;
-struct _WatchLink;
+class _Conn;
+class _WatchLink;
 
 
 // WCFS represents filesystem-level connection to wcfs server.
@@ -42,7 +42,7 @@ struct _WatchLink;
 struct WCFS {
     string  mountpoint;
 
-    tuple<Conn*, error>                 connect(zodb::Tid at);
+    tuple<refptr<_Conn>, error>         connect(zodb::Tid at);
     string                              _path(const string &obj);
     tuple<os::File, error>              _open(const string &path, int flags=O_RDONLY);
     pair<refptr<_WatchLink>, error>     _openwatch();

wcfs/internal/wcfs_virtmem.cpp

@@ -50,7 +50,6 @@ static string h(uint64_t v); // v -> 016x hex representation
 static error mmap_zero_into_ro(void *addr, size_t size);
 static error mmap_into_ro(void *addr, size_t size, const os::File &f, off_t offset);
 
-struct Conn;
 struct _File;
 struct _Mapping;
 struct PinReq;
@@ -58,15 +57,34 @@ struct PinReq;
 // Conn represents logical connection that provides view of data on wcfs
 // filesystem as of particular database state.
 //
-// XXX doc
-struct Conn {
+// It uses /head/bigfile/* and notifications received from /head/watch to
+// maintain isolated database view while at the same time sharing most of data
+// cache in OS pagecache of /head/bigfile/*.
+//
+// Use WCFS.connect(at) to create Conn.
+// Use .mmap to create new Mappings.
+// Use .resync to resync Conn onto different database view.
+//
+// Conn logically mirrors ZODB.Connection .
+typedef refptr<class _Conn> Conn;
+class _Conn {
     WCFS        *_wc;
     zodb::Tid   at;
-    WatchLink   _wlink;
+    WatchLink   _wlink; // watch/receive pins for created mappings
 
     sync::Mutex              _filemu;
     dict<zodb::Oid, _File*>  _filetab; // {} foid -> _file
 
+    // XXX ._pinWG, ._pinCancel
+
+    // don't new - create via WCFS.connect
+private:
+    _Conn();
+    ~_Conn();
+    friend tuple<Conn, error> WCFS::connect(zodb::Tid at);
+public:
+    void decref();
+
 public:
     error close();
     error resync(zodb::Tid at);
@@ -79,9 +97,10 @@ private:
 // _File represent isolated file view under Conn.
 //
 // XXX doc      XXX naming -> _FileView ?
+// XXX -> refptr ?
 struct _File {
-    Conn        *wconn;
-    zodb::Oid   foid;       // hex of ZBigFile root object ID
+    Conn        wconn;
+    zodb::Oid   foid;       // ZBigFile root object ID
     size_t      blksize;    // block size of this file  XXX -> off_t ?
     os::File    headf;      // file object of head/file
     off_t       headfsize;  // head/file size is known to be at least headfsize (size ↑=)
@@ -91,6 +110,7 @@ struct _File {
 };
 
 // _Mapping represents one mapping of _File.
+// XXX -> refptr ?
 struct _Mapping {
     _File   *file;
     int     blk_start;  // offset of this mapping in file
@@ -110,29 +130,27 @@ struct _Mapping {
 
 
 // connect creates new Conn viewing WCFS state as of @at.
-tuple<Conn*, error> WCFS::connect(zodb::Tid at) {
+tuple<Conn, error> WCFS::connect(zodb::Tid at) {
     WCFS *wc = this;
     // XXX err ctx
 
+    // TODO support !isolated mode
+
     WatchLink wlink;
     error err;
     tie(wlink, err) = wc->_openwatch();
     if (err != nil)
-        return make_tuple((Conn *)NULL, err);
+        return make_tuple(nil, err);
 
-    Conn *wconn = new Conn();
-    // TODO support !isolated mode
+    Conn wconn = adoptref(new _Conn());
     wconn->_wc      = wc;
     wconn->at       = at;
     wconn->_wlink   = wlink;
 
 
-    // XXX reenable
-#if 0
     pinCtx, wconn._pinCancel = context.with_cancel(context.background())
     wconn._pinWG = sync.WorkGroup(pinCtx)
     wconn._pinWG.go(wconn._pinner)
-#endif
 
     return make_tuple(wconn, nil);
 }
@@ -163,7 +181,7 @@ error Conn::close() {   // XXX error -> void?
     for (auto _ : wconn._filetab) {
         auto f = _.second;
         f->headf->close();    // XXX err
-        //f->headf = None
+        f->headf = nil;
 
         // XXX stop watching f
     }