Change names of Blob class methods that may be called when the blob object is...

Change names of Blob class methods that may be called when the blob object is ghosted.  We use a convention of _p_blob_whatever.

branches/ctheune-blobsupport/src/ZODB/Blobs/Blob.py

@@ -101,11 +101,17 @@ class Blob(Persistent):
     def _change(self):
         self._p_changed = 1
 
-    def _rc_clear(self):
+    # utility methods which should not cause the object's state to be
+    # loaded if they are called while the object is a ghost.  Thus,
+    # they are named with the _p_ convention and only operate against
+    # other _p_ instance attributes. We conventionally name these methods
+    # and attributes with a _p_blob prefix.
+
+    def _p_blob_clear(self):
         self._p_blob_readers = 0
         self._p_blob_writers = 0
 
-    def _rc_decref(self, mode):
+    def _p_blob_decref(self, mode):
         if mode.startswith('r') or mode == 'U':
             self._p_blob_readers = max(0, self._p_blob_readers - 1)
         elif mode.startswith('w') or mode.startswith('a'):
@@ -113,7 +119,7 @@ class Blob(Persistent):
         else:
             raise AssertionError, 'Unknown mode %s' % mode
 
-    def _get_refcounts(self):
+    def _p_blob_refcounts(self):
         # used by unit tests
         return self._p_blob_readers, self._p_blob_writers
 
@@ -162,14 +168,14 @@ class BlobDataManager:
                 
     def commit(self, object, transaction):
         if not self.subtransaction:
-            self.blob._rc_clear() # clear all blob refcounts
+            self.blob._p_blob_clear() # clear all blob refcounts
             filehandle = self.fhref()
             if filehandle is not None:
                 filehandle.close()
 
     def abort(self, object, transaction):
         if not self.subtransaction:
-            self.blob._rc_clear()
+            self.blob._p_blob_clear()
             filehandle = self.fhref()
             if filehandle is not None:
                 filehandle.close()
@@ -214,7 +220,7 @@ class BlobFile(file):
     def close(self):
         # we don't want to decref twice
         if not self.close_called:
-            self.blob._rc_decref(self.mode)
+            self.blob._p_blob_decref(self.mode)
             self.close_called = True
             super(BlobFile, self).close()
 

branches/ctheune-blobsupport/src/ZODB/Blobs/tests/transaction.txt

@@ -43,14 +43,14 @@ resulting filehandle is accomplished via the filehandle's read method:
     >>> connection2 = database.open()
     >>> root = connection2.root()
     >>> blob2 = root['myblob']
-    >>> blob2._get_refcounts()
+    >>> blob2._p_blob_refcounts()
     (0, 0)
     >>>
     >>> b1 = blob2.open("r")
     >>> b1.read()
     'abc'
     >>> # we reach into the implementation here, dont try this at home
-    >>> b1.blob._get_refcounts()[0]
+    >>> b1.blob._p_blob_refcounts()[0]
     1
 
 Let's make another filehandle for read only to blob2, this should bump
@@ -58,18 +58,18 @@ up its refcount by one, and each file handle has a reference to the
 (same) underlying blob:
 
     >>> b2 = blob2.open("r")
-    >>> b2.blob._get_refcounts()
+    >>> b2.blob._p_blob_refcounts()
     (2, 0)
-    >>> b1.blob._get_refcounts()
+    >>> b1.blob._p_blob_refcounts()
     (2, 0)
 
 Let's close the first filehandle we got from the blob, this should decrease
 its refcount by one:
 
     >>> b1.close()
-    >>> b1.blob._get_refcounts()
+    >>> b1.blob._p_blob_refcounts()
     (1, 0)
-    >>> b1.blob._get_refcounts()
+    >>> b1.blob._p_blob_refcounts()
     (1, 0)
 
 Let's abort this transaction, and ensure that the filehandles that we
@@ -77,9 +77,9 @@ opened are now closed and that the filehandle refcounts on the blob
 object are cleared.
 
     >>> transaction.abort()
-    >>> b1.blob._get_refcounts()
+    >>> b1.blob._p_blob_refcounts()
     (0, 0)
-    >>> b2.blob._get_refcounts()
+    >>> b2.blob._p_blob_refcounts()
     (0, 0)
     >>> b2.read()
     Traceback (most recent call last):
@@ -88,10 +88,10 @@ object are cleared.
 
 If we open a blob for writing, its write refcount should be nonzero:
 
-    >>> blob2._get_refcounts()
+    >>> blob2._p_blob_refcounts()
     (0, 0)
     >>> b2 = blob2.open('a')
-    >>> blob2._get_refcounts()
+    >>> blob2._p_blob_refcounts()
     (0, 1)
 
 While we are testing this, we don't need the storage directory and databases