diff mercurial/pure/parsers.py @ 47034:0d8ff1f4ab0c

revlog: add a `entry_binary` method on index

The revlog index is already responsible for unpacking the binary entry, it would be
simpler to make it responsible for packing them. In practice the C version of
the index is already doing this internally.

We introduce a "entry_binary" method that return the binary version of an
existing revision. The method currently need to also take the revlog header to
deal with the "first revision" special case. We will introduce further refactor
in a later changeset to split that logic out.

Differential Revision: https://phab.mercurial-scm.org/D10508

--- a/mercurial/pure/parsers.py	Thu Apr 15 12:08:34 2021 +0200
+++ b/mercurial/pure/parsers.py	Thu Apr 08 00:01:11 2021 +0200
@@ -127,10 +127,24 @@
             r = (offset_type(0, gettype(r[0])),) + r[1:]
         return r
 
+    def entry_binary(self, rev, header):
+        """return the raw binary string representing a revision"""
+        entry = self[rev]
+        p = revlog_constants.INDEX_ENTRY_V1.pack(*entry)
+        if rev == 0:
+            v_fmt = revlog_constants.INDEX_HEADER
+            v_bin = v_fmt.pack(header)
+            p = v_bin + p[v_fmt.size :]
+        return p
+
 
 class IndexObject(BaseIndexObject):
     def __init__(self, data):
-        assert len(data) % self.entry_size == 0
+        assert len(data) % self.entry_size == 0, (
+            len(data),
+            self.entry_size,
+            len(data) % self.entry_size,
+        )
         self._data = data
         self._lgt = len(data) // self.entry_size
         self._extra = []
@@ -272,6 +286,16 @@
             msg = b"cannot rewrite entries outside of this transaction"
             raise KeyError(msg)
 
+    def entry_binary(self, rev, header):
+        """return the raw binary string representing a revision"""
+        entry = self[rev]
+        p = revlog_constants.INDEX_ENTRY_V2.pack(*entry)
+        if rev == 0:
+            v_fmt = revlog_constants.INDEX_HEADER
+            v_bin = v_fmt.pack(header)
+            p = v_bin + p[v_fmt.size :]
+        return p
+
 
 class IndexObject2(Index2Mixin, IndexObject):
     pass