From: Richard Levitte <richard@levitte.org>
Date: Fri, 22 Jan 2016 11:37:31 +0000 (+0100)
Subject: Refactor file writing - arrange for use of bundled Perl modules as fallback
X-Git-Tag: OpenSSL_1_1_0-pre3~449
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=35c3a562c74aba6e3ac3d577a356b314a151740e;p=openssl

Refactor file writing - arrange for use of bundled Perl modules as fallback

For our own convenience, we need a mechanism to be able to fall back
on bundled Perl modules.  It's a minimal package that's called like
this:

    use with_fallback qw(Module1 Module2 ...);

For each module, it will try to require them from the system
installation, and failing that, it will temporarly add external/perl
and try to require transfer::{ModuleName}.  It requires that each
bundled Perl modules is accompanied by a small transfer module
(external/perl/transfer/ModuleName.pm in our example) that knows
exactly what to load.

Reviewed-by: Rich Salz <rsalz@openssl.org>
---

diff --git a/util/with_fallback.pm b/util/with_fallback.pm
new file mode 100644
index 0000000000..014f355156
--- /dev/null
+++ b/util/with_fallback.pm
@@ -0,0 +1,19 @@
+#! /usr/bin/perl
+
+package with_fallback;
+
+sub import {
+    use File::Basename;
+    use File::Spec::Functions;
+    foreach (@_) {
+	eval "require $_";
+	if ($@) {
+	    unshift @INC, catdir(dirname(__FILE__), "..", "external", "perl");
+	    my $transfer = "transfer::$_";
+	    eval "require $transfer";
+	    shift @INC;
+	    warn $@ if $@;
+	}
+    }
+}
+1;