.

wcfs/__init__.py

@@ -74,6 +74,8 @@ from .internal._wcfs import \
 # Raw files on wcfs can be accessed with ._path/._read/._stat/._open .
 #
 # WCFS logically mirrors ZODB.DB .
+#
+# XXX kill doc instead of C++.
 class WCFS(_WCFS):
     # .mountpoint   path to wcfs mountpoint
     # ._fwcfs       /.wcfs/zurl opened to keep the server from going away (at least cleanly)

wcfs/internal/wcfs.h

@@ -40,18 +40,33 @@ using std::pair;
 
 #include "wcfs_misc.h"
 
+// from wendelin/bigfile/virtmem.h
+extern "C" {
+struct BigFileH;
+}
+
+
 // wcfs::
 namespace wcfs {
 
-struct _File;
-struct _Mapping;
+typedef refptr<struct _Conn> Conn;
+typedef refptr<struct _Mapping> Mapping;
+typedef refptr<struct _FileH> FileH;
+typedef refptr<struct _WatchLink> WatchLink;
 struct PinReq;
-typedef refptr<class _Conn> Conn;
-typedef refptr<class _WatchLink> WatchLink;
 
 
 // WCFS represents filesystem-level connection to wcfs server.
-// XXX doc
+//
+// XXX Use join to create it?
+//
+// The primary way to access wcfs is to open logical connection viewing on-wcfs
+// data as of particular database state, and use that logical connection to
+// create base-layer mappings. See .connect and Conn for details.
+//
+// XXX raw files?
+//
+// WCFS logically mirrors ZODB.DB .
 struct WCFS {
     string  mountpoint;
 
@@ -69,7 +84,7 @@ struct WCFS {
 // cache in OS pagecache of /head/bigfile/*.
 //
 // Use WCFS.connect(at) to create Conn.
-// Use .mmap to create new Mappings.
+// Use .open to create new FileH.
 // Use .resync to resync Conn onto different database view.
 //
 // Conn logically mirrors ZODB.Connection .
@@ -79,8 +94,8 @@ struct _Conn : object {
     zodb::Tid   at;
     WatchLink   _wlink; // watch/receive pins for created mappings
 
-    sync::Mutex              _filemu;
-    dict<zodb::Oid, _File*>  _filetab; // {} foid -> _file
+    sync::Mutex             _filehmu;
+    dict<zodb::Oid, FileH>  _filehtab; // {} foid -> fileh
 
     sync::WorkGroup _pinWG;
     func<void()>    _pinCancel;
@@ -95,8 +110,8 @@ public:
 
 public:
     error close();
-    // XXX move mmap -> _FileH ?
-    pair<_Mapping*, error> mmap(zodb::Oid foid, int64_t blk_start, int64_t blk_len);
+    // XXX move mmap -> FileH
+    pair<Mapping, error> mmap(zodb::Oid foid, int64_t blk_start, int64_t blk_len);
     error resync(zodb::Tid at);
 
 private:
@@ -104,6 +119,64 @@ private:
     void _pin1(PinReq *req);
 };
 
+// FileH represent isolated file view under Conn.
+//
+// The file view is maintained to be as of @Conn.at database state.
+// The file view uses /head/<file>/data primarilty and @revX/<file>/data pin overrides.
+//
+// Use .mmap to map file view into memory.
+typedef refptr<struct _FileH> FileH;
+struct _FileH : object {
+    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 ↑=)
+
+    dict<int64_t, zodb::Tid>  _pinned; // {} blk -> rev   that wcfs already sent us for this file
+    vector<Mapping>           _mmaps;  // []Mapping ↑blk_start    mappings of this file
+
+    // don't new - create via Conn.open
+private:
+    _FileH();
+    ~_FileH();
+    // XXX -> friend Conn::open
+    friend pair<Mapping, error> _Conn::mmap(zodb::Oid foid, int64_t blk_start, int64_t blk_len);
+public:
+    void decref();
+};
+
+// Mapping represents one mapping of FileH.
+typedef refptr<struct _Mapping> Mapping;
+struct _Mapping : object {
+    FileH   fileh;
+    int64_t blk_start;  // offset of this mapping in file
+
+    BigFileH *virt_fileh;   // mmapped under this virtmem file handle   XXX -> VMA  XXX can be nil
+    uint8_t  *mem_start;    // mmapped memory [mem_start, mem_stop)
+    uint8_t  *mem_stop;
+
+    int64_t blk_stop() const {
+        //XXX reenable
+        //ASSERT((mem_stop - mem_start) % file->blksize == 0);
+        return blk_start + (mem_stop - mem_start) / fileh->_blksize;
+    }
+
+    error _remmapblk(int64_t blk, zodb::Tid at);
+    void  remmap_blk(int64_t blk);
+    void  unmap();
+
+    // don't new - create via FileH.mmap
+private:
+    _Mapping();
+    ~_Mapping();
+    // XXX -> friend FileH.mmap
+    friend pair<Mapping, error> _Conn::mmap(zodb::Oid foid, int64_t blk_start, int64_t blk_len);
+public:
+    void decref();
+};
+
+
 
 }   // wcfs::