.

wcfs/wcfs.go

@@ -1616,7 +1616,8 @@ func main() {
 	// If a user opens it, it will start to get tids of through which
 	// zhead.at was, starting from the time when .wcfs/zhead was opened.
 	// There can be multiple openers. Once opened, the file must be read,
-	// as wcfs blocks waiting for data to be read before XXX.
+	// as wcfs blocks waiting for data to be read when processing
+	// invalidations.
 	mkfile(&_wcfs, "zhead", &_wcfs_Zhead{
 		fsNode: newFSNode(fSticky),
 	})

wcfs/wcfs_test.py

@@ -147,7 +147,7 @@ class tDB:
         t._headv.append(head)
         return head
 
-    # wcsync makes sure wc synchronized to latest committed transaction.
+    # wcsync makes sure wcfs synchronized to latest committed transaction.
     def wcsync(t):
         while len(t._wc_zheadv) < len(t._headv):
             l = t._wc_zheadfh.readline()
@@ -177,16 +177,54 @@ class tDB:
 
         return os.path.join(t.wc.mountpoint, obj)
 
-    # read reads file corresponding to obj on wcfs
+    # read reads file corresponding to obj on wcfs.
     def read(t, obj, at=None):
         path = t.path(obj, at=at)
         return readfile(path)
 
-    # stat stats file corresponding to obj on wcfs
+    # stat stats file corresponding to obj on wcfs.
     def stat(t, obj, at=None):
         path = t.path(obj, at=at)
         return os.stat(path)
 
+    # open opens file corresponding to obj on wcfs.
+    def open(t, obj, at=None):
+        path = t.path(obj, at=at)
+        return open(path)
+
+    # readblk reads ZBigFile[blk] from wcfs.
+    @func
+    def readblk(t, zf, blk, at=None):
+        assert isinstance(zf, ZBigFile)
+        f = t.open(zf, at=at)   # XXX binary, !buffered
+        defer(f.close)
+
+        blksize = zf.blksize
+        f.seek(blk*blksize)
+        n = blksize
+        data = b''
+        while n > 0:
+            chunk = f.read(n)
+            assert len(chunk) > 0
+            data += chunk
+            n    -= len(chunk)
+        return data
+
+
+    # assertData asserts that wcfs file corresponding to zf has data blocks as specified in expectv.
+    #
+    # Expected blocks may be given with size < zf.blksize. In such case they
+    # are implicitly appended with trailing zeros.
+    def assertData(t, zf, expectv, at=None):
+        assert isinstance(zf, ZBigFile)
+        data = t.read(zf, at=at)
+        assert len(data) == len(expectv)*zf.blksize
+        for i, blk in enumerate(expectv):
+            assert len(blk) <= zf.blksize
+            blk += b'\0'*(zf.blksize - len(blk))    # trailing zeros
+            assert data[i*zf.blksize:(i+1)*zf.blksize] == blk
+
+
 
 # XXX text ...
 # XXX parametrize zblk0, zblk1  XXX or just rely on tox?
@@ -213,11 +251,9 @@ def test_wcfs():
     assert _.st_size  == 0
     assert _.st_mtime == tidtime(tid1)
 
-
     # commit data to f and make sure we can see it on wcfs
     # use !wcfs mode so that we prepare data independently of wcfs code paths.
-    #hole = 10      XXX reenable
-    hole = 1
+    hole = 10
     fh  = f.fileh_open(_use_wcfs=False)
     vma = fh.mmap(hole, 1)    # 1 page at offset=10
     s   = b"hello world"
@@ -226,13 +262,18 @@ def test_wcfs():
     t.commit()
     t.wcsync()    # sync wcfs to ZODB
 
-    # we wrote "hello world" after hole'th block, but size is always mutiple of blksize.
-    fsize = (hole + 1)*blksize
-
+    fsize = (hole + 1)*blksize  # size is always mutiple of blksize.
     _ = t.stat(f)
     assert _.st_size  == fsize
     assert _.st_mtime == tidtime(t.head)
 
+    t.assertData(f, [b'']*hole + [s])
+
+
+    for i in range(hole):
+        assert t.readblk(f, i) == b'\0'*blksize
+    assert t.readblk(f, hole)  == s + b'\0'*(blksize - len(s))
+
     data = t.read(f)
     assert len(data) == fsize
     for i in range(hole):