D11934: changelog-v2: use helper constant in the code to pack/unpack entries

[marmoute (Pierre-Yves David)]

marmoute created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.

REVISION SUMMARY
  This makes the code simpler to read and modify. This is probably less
  efficient, but we are talking about the Python implementation here, so
  performance is concerne secondary to readability.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D11934

AFFECTED FILES
  mercurial/pure/parsers.py
  mercurial/revlogutils/constants.py

CHANGE DETAILS

diff --git a/mercurial/revlogutils/constants.py b/mercurial/revlogutils/constants.py
--- a/mercurial/revlogutils/constants.py
+++ b/mercurial/revlogutils/constants.py
@@ -184,6 +184,15 @@
 #  27 bytes: Padding to align to 96 bytes (see RevlogV2Plan wiki page)
 INDEX_ENTRY_CL_V2 = struct.Struct(b">Qiiii20s12xQiB27x")
 assert INDEX_ENTRY_CL_V2.size == 32 * 3, INDEX_ENTRY_V2.size
+INDEX_ENTRY_V2_IDX_OFFSET = 0
+INDEX_ENTRY_V2_IDX_COMPRESSED_LENGTH = 1
+INDEX_ENTRY_V2_IDX_UNCOMPRESSED_LENGTH = 2
+INDEX_ENTRY_V2_IDX_PARENT_1 = 3
+INDEX_ENTRY_V2_IDX_PARENT_2 = 4
+INDEX_ENTRY_V2_IDX_NODEID = 5
+INDEX_ENTRY_V2_IDX_SIDEDATA_OFFSET = 6
+INDEX_ENTRY_V2_IDX_SIDEDATA_COMPRESSED_LENGTH = 7
+INDEX_ENTRY_V2_IDX_COMPRESSION_MODE = 8
 
 # revlog index flags
 
diff --git a/mercurial/pure/parsers.py b/mercurial/pure/parsers.py
--- a/mercurial/pure/parsers.py
+++ b/mercurial/pure/parsers.py
@@ -880,18 +880,43 @@
 
     def _unpack_entry(self, rev, data, r=True):
         items = self.index_format.unpack(data)
-        entry = items[:3] + (rev, rev) + items[3:8]
-        data_comp = items[8] & 3
-        sidedata_comp = (items[8] >> 2) & 3
-        return entry + (data_comp, sidedata_comp)
+        return (
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_OFFSET],
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_COMPRESSED_LENGTH],
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_UNCOMPRESSED_LENGTH],
+            rev,
+            rev,
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_PARENT_1],
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_PARENT_2],
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_NODEID],
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_SIDEDATA_OFFSET],
+            items[
+                revlog_constants.INDEX_ENTRY_V2_IDX_SIDEDATA_COMPRESSED_LENGTH
+            ],
+            items[revlog_constants.INDEX_ENTRY_V2_IDX_COMPRESSION_MODE] & 3,
+            (items[revlog_constants.INDEX_ENTRY_V2_IDX_COMPRESSION_MODE] >> 2)
+            & 3,
+        )
 
     def _pack_entry(self, rev, entry):
-        assert entry[3] == rev, entry[3]
-        assert entry[4] == rev, entry[4]
-        data = entry[:3] + entry[5:10]
-        data_comp = entry[10] & 3
-        sidedata_comp = (entry[11] & 3) << 2
-        data += (data_comp | sidedata_comp,)
+
+        base = entry[revlog_constants.ENTRY_DELTA_BASE]
+        link_rev = entry[revlog_constants.ENTRY_LINK_REV]
+        assert base == rev, (base, rev)
+        assert link_rev == rev, (link_rev, rev)
+        data = (
+            entry[revlog_constants.ENTRY_DATA_OFFSET],
+            entry[revlog_constants.ENTRY_DATA_COMPRESSED_LENGTH],
+            entry[revlog_constants.ENTRY_DATA_UNCOMPRESSED_LENGTH],
+            entry[revlog_constants.ENTRY_PARENT_1],
+            entry[revlog_constants.ENTRY_PARENT_2],
+            entry[revlog_constants.ENTRY_NODE_ID],
+            entry[revlog_constants.ENTRY_SIDEDATA_OFFSET],
+            entry[revlog_constants.ENTRY_SIDEDATA_COMPRESSED_LENGTH],
+            entry[revlog_constants.ENTRY_DATA_COMPRESSION_MODE] & 3
+            | (entry[revlog_constants.ENTRY_SIDEDATA_COMPRESSION_MODE] & 3)
+            << 2,
+        )
         return self.index_format.pack(*data)
 
 



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