Merge branch 'gb/filter-branch-progress'

Give progress meter to "git filter-branch".

* gb/filter-branch-progress:
  filter-branch: make report-progress more readable
  filter-branch: add passed/remaining seconds on progress

git-filter-branch.sh

@@ -275,11 +275,41 @@ commits=$(wc -l <../revs | tr -d " ")
 test $commits -eq 0 && die "Found nothing to rewrite"
 
 # Rewrite the commits
+report_progress ()
+{
+	if test -n "$progress" &&
+		test $git_filter_branch__commit_count -gt $next_sample_at
+	then
+		count=$git_filter_branch__commit_count
+
+		now=$(date +%s)
+		elapsed=$(($now - $start_timestamp))
+		remaining=$(( ($commits - $count) * $elapsed / $count ))
+		if test $elapsed -gt 0
+		then
+			next_sample_at=$(( ($elapsed + 1) * $count / $elapsed ))
+		else
+			next_sample_at=$(($next_sample_at + 1))
+		fi
+		progress=" ($elapsed seconds passed, remaining $remaining predicted)"
+	fi
+	printf "\rRewrite $commit ($count/$commits)$progress    "
+}
 
 git_filter_branch__commit_count=0
+
+progress= start_timestamp=
+if date '+%s' 2>/dev/null | grep -q '^[0-9][0-9]*$'
+then
+	next_sample_at=0
+	progress="dummy to ensure this is not empty"
+	start_timestamp=$(date '+%s')
+fi
+
 while read commit parents; do
 	git_filter_branch__commit_count=$(($git_filter_branch__commit_count+1))
-	printf "\rRewrite $commit ($git_filter_branch__commit_count/$commits)"
+
+	report_progress
 
 	case "$filter_subdir" in
 	"")