From 9e80c5710e8e8005dee553b4583dc062dfc3ca62 Mon Sep 17 00:00:00 2001
From: David Steele <david@pgmasters.net>
Date: Sat, 14 Mar 2020 12:39:29 -0400
Subject: [PATCH] Use a checksum to build configure.ac more efficiently.

Building the configure.ac script can take multiple seconds depending on the state of the autoconf cache. Use a checksum to only rebuild when configure.ac has changed no matter how the timestamps have changed.
---
 src/.gitignore |  2 +-
 src/configure  |  2 ++
 test/test.pl   | 35 ++++++++++++++++++++++++-----------
 3 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/src/.gitignore b/src/.gitignore
index 535f11650..a5ef16f4f 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -1,5 +1,5 @@
 /.build
-/autom4te.cache
+autom4te.cache
 /config.log
 /config.status
 /Makefile
diff --git a/src/configure b/src/configure
index 302f9a4b6..9016ecab7 100755
--- a/src/configure
+++ b/src/configure
@@ -5267,3 +5267,5 @@ if test -n "$ac_unrecognized_opts" && test "$enable_option_checking" != no; then
   { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
 $as_echo "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2;}
 fi
+
+# Generated from src/build/configure.ac sha1 ebb41aa471ed3dc451cf95db394ec83bf08f759d
diff --git a/test/test.pl b/test/test.pl
index 6e9eb6420..425a4e382 100755
--- a/test/test.pl
+++ b/test/test.pl
@@ -14,6 +14,7 @@ use English '-no_match_vars';
 # Convert die to confess to capture the stack trace
 $SIG{__DIE__} = sub { Carp::confess @_ };
 
+use Digest::SHA qw(sha1_hex);
 use File::Basename qw(dirname);
 use Getopt::Long qw(GetOptions);
 use Cwd qw(abs_path cwd);
@@ -486,21 +487,33 @@ eval
             #-----------------------------------------------------------------------------------------------------------------------
             if (!$bSmart || grep(/^src\/build\/configure\.ac/, @stryModifiedList))
             {
-                my $strConfigure = executeTest("autoconf ${strBackRestBase}/src/build/configure.ac");
-
-                # Trim off any trailing LFs
-                $strConfigure = trim($strConfigure) . "\n";
-
-                # Remove unused options from help
-                $strConfigure =~ s/^  --((?!bin).)*dir=DIR.*\n//mg;
-                $strConfigure =~ s/^  --sbindir=DIR.*\n//mg;
-
-                # Save into the src dir
+                # Set build file
                 my @stryBuilt;
                 my $strBuilt = 'src/configure';
 
-                if (buildPutDiffers($oStorageBackRest, "${strBackRestBase}/${strBuilt}", $strConfigure))
+                # Get configure.ac and configure to see if anything has changed
+                my $strConfigureAc = ${$oStorageBackRest->get('src/build/configure.ac')};
+                my $strConfigureAcHash = sha1_hex($strConfigureAc);
+                my $rstrConfigure = $oStorageBackRest->get($oStorageBackRest->openRead($strBuilt, {bIgnoreMissing => true}));
+
+                # Check if configure needs to be regenerated
+                if (!defined($rstrConfigure) || !defined($$rstrConfigure) ||
+                    $strConfigureAcHash ne substr($$rstrConfigure, length($$rstrConfigure) - 41, 40))
                 {
+                    # Generate configure
+                    my $strConfigure = executeTest("cd ${strBackRestBase}/src/build && autoconf --output=-");
+                    $strConfigure =
+                        trim($strConfigure) . "\n\n# Generated from src/build/configure.ac sha1 ${strConfigureAcHash}\n";
+
+                    # Remove unused options from help
+                    $strConfigure =~ s/^  --((?!bin).)*dir=DIR.*\n//mg;
+                    $strConfigure =~ s/^  --sbindir=DIR.*\n//mg;
+
+                    # Save into the src dir
+                    $oStorageBackRest->put(
+                        $oStorageBackRest->openWrite("${strBackRestBase}/${strBuilt}", {strMode => '0755'}), $strConfigure);
+
+                    # Add to built list
                     push(@stryBuilt, $strBuilt);
                     push(@stryBuiltAll, @stryBuilt);
                     push(@stryModifiedList, @stryBuilt);