[PATCH] debugdeltachain: output information about sparse read if enabled

[Paul Morelle]

# HG changeset patch
# User Paul Morelle <paul.morelle at octobus.net>
# Date 1509002829 -7200
#      Thu Oct 26 09:27:09 2017 +0200
# Node ID 13a6c881be35e7651a12f8c3442abfade2b77c88
# Parent  602c168c0207c443ac61f7a7c727b31cfb0b86ad
# EXP-Topic debugdeltachain
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 13a6c881be35
debugdeltachain: output information about sparse read if enabled

diff -r 602c168c0207 -r 13a6c881be35 mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Tue Nov 07 13:18:49 2017 -0500
+++ b/mercurial/debugcommands.py	Thu Oct 26 09:27:09 2017 +0200
@@ -587,11 +587,22 @@
                     the delta chain for this revision
     :``extraratio``: extradist divided by chainsize; another representation of
                     how much unrelated data is needed to load this delta chain
+
+    If the repository is configured to use the sparse read, additional keywords
+    are available:
+
+    :``readsize``:     total size of data read from the disk for a revision
+                       (sum of the sizes of all the blocks)
+    :``largestblock``: size of the largest block of data read from the disk
+    :``readdensity``:  density of useful bytes in the data read from the disk
+
+    The sparse read can be enabled with experimental.sparse-read = True
     """
     opts = pycompat.byteskwargs(opts)
     r = cmdutil.openrevlog(repo, 'debugdeltachain', file_, opts)
     index = r.index
     generaldelta = r.version & revlog.FLAG_GENERALDELTA
+    withsparseread = getattr(r, '_withsparseread', False)
 
     def revinfo(rev):
         e = index[rev]
@@ -625,17 +636,29 @@
 
     fm = ui.formatter('debugdeltachain', opts)
 
-    fm.plain('    rev  chain# chainlen     prev   delta       '
-             'size    rawsize  chainsize     ratio   lindist extradist '
-             'extraratio\n')
+    header = ('    rev  chain# chainlen     prev   delta       '
+              'size    rawsize  chainsize     ratio   lindist extradist '
+              'extraratio')
+    fmfields = ('rev chainid chainlen prevrev deltatype compsize '
+                'uncompsize chainsize chainratio lindist extradist '
+                'extraratio')
+    fmformats = '%7d %7d %8d %8d %7s %10d %10d %10d %9.5f %9d %9d %10.5f'
+    if withsparseread:
+        header += '   readsize largestblk rddensity'
+        fmfields += ' readsize largestblock readdensity'
+        fmformats += ' %10d %10d %9.5f'
+
+    fm.plain(header + '\n')
 
     chainbases = {}
     for rev in r:
         comp, uncomp, deltatype, chain, chainsize = revinfo(rev)
         chainbase = chain[0]
         chainid = chainbases.setdefault(chainbase, len(chainbases) + 1)
-        basestart = r.start(chainbase)
-        revstart = r.start(rev)
+        start = r.start
+        length = r.length
+        basestart = start(chainbase)
+        revstart = start(rev)
         lineardist = revstart + comp - basestart
         extradist = lineardist - chainsize
         try:
@@ -646,19 +669,33 @@
         chainratio = float(chainsize) / float(uncomp)
         extraratio = float(extradist) / float(chainsize)
 
+        fmargs = (rev, chainid, len(chain), prevrev, deltatype, comp,
+                  uncomp, chainsize, chainratio, lineardist, extradist,
+                  extraratio)
+        fmkwargs = dict(rev=rev, chainid=chainid, chainlen=len(chain),
+                        prevrev=prevrev, deltatype=deltatype, compsize=comp,
+                        uncompsize=uncomp, chainsize=chainsize,
+                        chainratio=chainratio, lindist=lineardist,
+                        extradist=extradist, extraratio=extraratio)
+        if withsparseread:
+            readsize = 0
+            largestblock = 0
+            for revschunk in revlog._slicechunk(r, chain):
+                blkend = start(revschunk[-1]) + length(revschunk[-1])
+                blksize = blkend - start(revschunk[0])
+
+                readsize += blksize
+                if largestblock < blksize:
+                    largestblock = blksize
+
+            readdensity = float(chainsize) / float(readsize)
+
+            fmargs += (readsize, largestblock, readdensity)
+            fmkwargs.update(readsize=readsize, largestblock=largestblock,
+                            readdensity=readdensity)
+
         fm.startitem()
-        fm.write('rev chainid chainlen prevrev deltatype compsize '
-                 'uncompsize chainsize chainratio lindist extradist '
-                 'extraratio',
-                 '%7d %7d %8d %8d %7s %10d %10d %10d %9.5f %9d %9d %10.5f\n',
-                 rev, chainid, len(chain), prevrev, deltatype, comp,
-                 uncomp, chainsize, chainratio, lineardist, extradist,
-                 extraratio,
-                 rev=rev, chainid=chainid, chainlen=len(chain),
-                 prevrev=prevrev, deltatype=deltatype, compsize=comp,
-                 uncompsize=uncomp, chainsize=chainsize,
-                 chainratio=chainratio, lindist=lineardist,
-                 extradist=extradist, extraratio=extraratio)
+        fm.write(fmfields, fmformats + '\n', *fmargs, **fmkwargs)
 
     fm.end()