From 3bdd905ddf3c6c9feabbf88901bf4f655924cb61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
Date: Thu, 16 Oct 2014 13:12:07 +0200
Subject: [PATCH 1/2] Prefer external csnappy library in Sereal::Decoder
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This patch checks for presence of csnappy library and header file and
if they are available, they will be used to link to the
Sereal::Decoder XS module. Otherwise the bundled csnappy code will be
used.

<https://github.com/Sereal/Sereal/issues/72>

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 Perl/Decoder/Makefile.PL   | 15 ++++++++++++++-
 Perl/Decoder/srl_decoder.c |  5 +++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Perl/Decoder/Makefile.PL b/Perl/Decoder/Makefile.PL
index 71cd40d..864b89b 100644
--- a/Perl/Decoder/Makefile.PL
+++ b/Perl/Decoder/Makefile.PL
@@ -25,6 +25,7 @@ our $OPTIMIZE;
 #     #define MINIZ_LITTLE_ENDIAN 1
 #     #define MINIZ_HAS_64BIT_REGISTERS 1
 
+my $libs = '';
 my $defines = join " ", map "-D$_", grep exists $ENV{$_}, qw(NOINLINE DEBUG MEMDEBUG NDEBUG);
 if ($Config{gccversion}) {
     $OPTIMIZE = '-O3 -Wall -W';
@@ -52,6 +53,18 @@ if ($Config{osname} eq 'hpux' && not $Config{gccversion}) {
   $defines .= " -Dinline= ";
 }
 
+# Prefer external csnappy library over the bundled one.
+require Devel::CheckLib;
+my $have_csnappy = Devel::CheckLib::check_lib(
+    lib      => 'csnappy',
+    header   => 'csnappy.h'
+);
+
+if ($have_csnappy) {
+    $libs .= ' -lcsnappy';
+    $defines .= ' -DHAVE_CSNAPPY';
+}
+
 # See lib/ExtUtils/MakeMaker.pm for details of how to influence
 # the contents of the Makefile that is written.
 WriteMakefile1(
@@ -89,7 +102,7 @@ WriteMakefile1(
     LICENSE => 'perl',
     ABSTRACT_FROM => 'lib/Sereal/Decoder.pm',
     AUTHOR => 'Steffen Mueller <smueller@cpan.org>, Yves Orton <yves@cpan.org>',
-    LIBS              => [''], # e.g., '-lm'
+    LIBS              => [$libs], # e.g., '-lm'
     DEFINE            => $defines,
     INC               => '-I.', # e.g., '-I. -I/usr/include/other'
     OPTIMIZE          => $OPTIMIZE,
diff --git a/Perl/Decoder/srl_decoder.c b/Perl/Decoder/srl_decoder.c
index 890a25c..09b5e52 100644
--- a/Perl/Decoder/srl_decoder.c
+++ b/Perl/Decoder/srl_decoder.c
@@ -51,7 +51,12 @@ extern "C" {
 #include "ptable.h"
 #include "srl_protocol.h"
 
+#if defined(HAVE_CSNAPPY)
+#include <csnappy.h>
+#else
 #include "snappy/csnappy_decompress.c"
+#endif
+
 #include "miniz.h"
 
 /* 5.8.8 and earlier have a nasty bug in their handling of overloading:
-- 
1.9.3