revsetbenchmark: simplify and convert the script to python

The script is now in python. That translation is very raw, more improvement to
comes:

The "current code" and "base" entry have been dropped.  This is trivial to get
same result using a tagged revision or "." in the list of benchmarked revision.

contrib/revsetbenchmarks.py

@@ -1,4 +1,4 b''
-#!/usr/bin/env bash
+#!/usr/bin/env python
 
 # Measure the performance of a list of revsets against multiple revisions
 # defined by parameter. Checkout one by one and run perfrevset with every
@@ -13,77 +13,46 b''
 # This script also does one run of the current version of mercurial installed
 # to compare performance.
 
-HG="hg update"
+import sys
+from subprocess import check_call, check_output
+
+HG="hg update --quiet --check"
 PERF="./hg --config extensions.perf=contrib/perf.py perfrevset"
-BASE_PERF="hg --config extensions.perf=contrib/perf.py perfrevset"
 
-TARGETS=$1
-shift
-# read from a file or from standard output
-if [ $# -ne 0 ]; then
-    readarray REVSETS < $1
-else
-    readarray REVSETS
-fi
+target_rev = sys.argv[1]
 
-hg update --quiet
+revsetsfile = sys.stdin
+if len(sys.argv) > 2:
+    revsetsfile = open(sys.argv[2])
 
-echo "Starting time benchmarking"
-echo
+revsets = [l.strip() for l in revsetsfile]
 
-echo "Revsets to benchmark"
-echo "----------------------------"
+print "Revsets to benchmark"
+print "----------------------------"
 
-for (( j = 0; j < ${#REVSETS[@]}; j++ ));
-do
-  echo "${j}) ${REVSETS[$j]}"
-done
-
-echo "----------------------------"
-echo
+for idx, rset in enumerate(revsets):
+    print "%i) %s" % (idx, rset)
 
-# Benchmark baseline
-echo "Benchmarking baseline"
+print "----------------------------"
+print
 
-for (( j = 0; j < ${#REVSETS[@]}; j++ ));
-  do
-    echo -n "${j}) "
-    $BASE_PERF "${REVSETS[$j]}"
-done
+revs = check_output("hg log --template='{rev}\n' --rev " + target_rev,
+                    shell=True);
 
-echo
-echo
+revs = [r for r in revs.split() if r]
 
 # Benchmark revisions
-for i in $(hg log --template='{rev}\n' --rev $TARGETS);
-do
-  echo "----------------------------"
-  echo -n "Revision: "
-  hg log -r $i --template "{desc|firstline}\n"
-
-  echo "----------------------------"
-  $HG $i
-  for (( j = 0; j < ${#REVSETS[@]}; j++ ));
-  do
-    echo -n "${j}) "
-    $PERF "${REVSETS[$j]}"
-  done
-  echo "----------------------------"
-done
+for r in revs:
+    print "----------------------------"
+    sys.stdout.write("Revision: ")
+    sys.stdout.flush()
+    check_call('hg log -r %s --template "{desc|firstline}\n"' % r, shell=True)
 
-$HG
-
-# Benchmark current code
-echo "Benchmarking current code"
+    print "----------------------------"
+    check_call(HG + ' ' + r, shell=True)
+    for idx, rset in enumerate(revsets):
+        sys.stdout.write("%i) " % idx)
+        sys.stdout.flush()
+        check_call(PERF + ' "%s"' % rset, shell=True)
+    print "----------------------------"
 
-for (( j = 0; j < ${#REVSETS[@]}; j++ ));
-  do
-    echo -n "${j}) "
-    $PERF "${REVSETS[$j]}"
-done
-
-
-echo
-echo "Time benchmarking finished"
-
-