[PATCH 4 of 5 lfs-v2] revlog: REVIDX_ISLARGEFILE flag

[Remi Chaintron]

# HG changeset patch
# User Remi Chaintron <remi at fb.com>
# Date 1479829452 0
#      Tue Nov 22 15:44:12 2016 +0000
# Branch stable
# Node ID 02ae3995e54d3e38e059224f4e56b998735b5be2
# Parent  66391d01bb92ff5f1d14033c00389214f78f25cc
revlog: REVIDX_ISLARGEFILE flag

Add the REVIDX_ISLARGEFILE flag for the `lfs` extension to interact with
revisions by registering transforms in the flagprocessor.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -54,11 +54,13 @@
 
 # revlog index flags
 REVIDX_ISCENSORED = (1 << 15) # revision has censor metadata, must be verified
+REVIDX_ISLARGEFILE = (1 << 14)
 REVIDX_DEFAULT_FLAGS = 0
-REVIDX_KNOWN_FLAGS = REVIDX_ISCENSORED
+REVIDX_KNOWN_FLAGS = REVIDX_ISCENSORED | REVIDX_ISLARGEFILE
 # stable order in which flags need to be processed by the flagprocessor
 REVIDX_FLAGS_PROCESSING_ORDER = [
     REVIDX_ISCENSORED,
+    REVIDX_ISLARGEFILE,
 ]
 
 # max size of revlog with inline data
@@ -1773,6 +1775,10 @@
         """Check if a file revision is censored."""
         return False
 
+    def islargefile(self, rev):
+        """Check if a file revision is flagged as large."""
+        return self.flags(rev) & REVIDX_ISLARGEFILE
+
     def _peek_iscensored(self, baserev, delta, flush):
         """Quickly check if a delta produces a censored revision."""
         return False