obsstore: refactor v1 logic to fix 32 byte hash support

Refactor the v1 logic to determine the node parsing based on the flag.
Move the predecessor out of the fixed part and handle it like the other
nodes, removing most of the duplicated code for parsing 20/32 bytes
hashes.

Differential Revision: https://phab.mercurial-scm.org/D8801

mercurial/obsolete.py

@@ -328,7 +328,7 b' def _fm0decodemeta(data):'
 #
 # - remaining bytes: the metadata, each (key, value) pair after the other.
 _fm1version = 1
-_fm1fixed = b'>IdhHBBB20s'
+_fm1fixed = b'>IdhHBBB'
 _fm1nodesha1 = b'20s'
 _fm1nodesha256 = b'32s'
 _fm1nodesha1size = _calcsize(_fm1nodesha1)
@@ -360,48 +360,36 b' def _fm1purereadmarkers(data, off, stop)'
     while off < stop:
         # read fixed part
         o1 = off + fsize
-        t, secs, tz, flags, numsuc, numpar, nummeta, prec = ufixed(data[off:o1])
+        t, secs, tz, flags, numsuc, numpar, nummeta = ufixed(data[off:o1])
 
         if flags & sha2flag:
-            # FIXME: prec was read as a SHA1, needs to be amended
+            nodefmt = sha2fmt
+            nodesize = sha2size
+        else:
+            nodefmt = sha1fmt
+            nodesize = sha1size
 
-            # read 0 or more successors
-            if numsuc == 1:
-                o2 = o1 + sha2size
-                sucs = (data[o1:o2],)
-            else:
-                o2 = o1 + sha2size * numsuc
-                sucs = unpack(sha2fmt * numsuc, data[o1:o2])
+        (prec,) = unpack(nodefmt, data[o1 : o1 + nodesize])
+        o1 += nodesize
 
-            # read parents
-            if numpar == noneflag:
-                o3 = o2
-                parents = None
-            elif numpar == 1:
-                o3 = o2 + sha2size
-                parents = (data[o2:o3],)
-            else:
-                o3 = o2 + sha2size * numpar
-                parents = unpack(sha2fmt * numpar, data[o2:o3])
+        # read 0 or more successors
+        if numsuc == 1:
+            o2 = o1 + nodesize
+            sucs = (data[o1:o2],)
         else:
-            # read 0 or more successors
-            if numsuc == 1:
-                o2 = o1 + sha1size
-                sucs = (data[o1:o2],)
-            else:
-                o2 = o1 + sha1size * numsuc
-                sucs = unpack(sha1fmt * numsuc, data[o1:o2])
+            o2 = o1 + nodesize * numsuc
+            sucs = unpack(nodefmt * numsuc, data[o1:o2])
 
-            # read parents
-            if numpar == noneflag:
-                o3 = o2
-                parents = None
-            elif numpar == 1:
-                o3 = o2 + sha1size
-                parents = (data[o2:o3],)
-            else:
-                o3 = o2 + sha1size * numpar
-                parents = unpack(sha1fmt * numpar, data[o2:o3])
+        # read parents
+        if numpar == noneflag:
+            o3 = o2
+            parents = None
+        elif numpar == 1:
+            o3 = o2 + nodesize
+            parents = (data[o2:o3],)
+        else:
+            o3 = o2 + nodesize * numpar
+            parents = unpack(nodefmt * numpar, data[o2:o3])
 
         # read metadata
         off = o3 + metasize * nummeta
@@ -423,7 +411,7 b' def _fm1encodeonemarker(marker):'
     if flags & usingsha256:
         _fm1node = _fm1nodesha256
     numsuc = len(sucs)
-    numextranodes = numsuc
+    numextranodes = 1 + numsuc
     if parents is None:
         numpar = _fm1parentnone
     else:
@@ -624,6 +612,7 b' class obsstore(object):'
         return True if a new marker have been added, False if the markers
         already existed (no op).
         """
+        flag = int(flag)
         if metadata is None:
             metadata = {}
         if date is None:
@@ -636,11 +625,18 b' class obsstore(object):'
                     date = dateutil.makedate()
             else:
                 date = dateutil.makedate()
-        if len(prec) != 20:
-            raise ValueError(prec)
-        for succ in succs:
-            if len(succ) != 20:
-                raise ValueError(succ)
+        if flag & usingsha256:
+            if len(prec) != 32:
+                raise ValueError(prec)
+            for succ in succs:
+                if len(succ) != 32:
+                    raise ValueError(succ)
+        else:
+            if len(prec) != 20:
+                raise ValueError(prec)
+            for succ in succs:
+                if len(succ) != 20:
+                    raise ValueError(succ)
         if prec in succs:
             raise ValueError(
                 'in-marker cycle with %s' % pycompat.sysstr(node.hex(prec))
@@ -659,7 +655,7 b' class obsstore(object):'
                     % (pycompat.bytestr(k), pycompat.bytestr(v))
                 )
 
-        marker = (bytes(prec), tuple(succs), int(flag), metadata, date, parents)
+        marker = (bytes(prec), tuple(succs), flag, metadata, date, parents)
         return bool(self.add(transaction, [marker]))
 
     def add(self, transaction, markers):