TAP: Add filtering to RecursiveCopy

Allow RecursiveCopy to accept a filter function so callers can
exclude unwanted files. Also POD-ify it.

Author: ringerc

src/test/perl/RecursiveCopy.pm

@@ -1,4 +1,18 @@
-# RecursiveCopy, a simple recursive copy implementation
+
+=pod
+
+=head1 NAME
+
+RecursiveCopy - simple recursive copy implementation
+
+=head1 SYNOPSIS
+
+use RecursiveCopy;
+
+RecursiveCopy::copypath($from, $to);
+
+=cut
+
 package RecursiveCopy;
 
 use strict;
@@ -7,10 +21,56 @@ use warnings;
 use File::Basename;
 use File::Copy;
 
+=pod
+
+=head2 copypath($from, $to)
+
+Copy all files and directories from $from to $to. Raises an exception
+if a file would be overwritten, the source dir can't be read, or any
+I/O operation fails.  Always returns true. On failure the copy may be
+in some incomplete state; no cleanup is attempted.
+
+If the keyword param 'filterfn' is defined it's invoked as a sub that
+returns true if the file/directory should be copied, false otherwise.
+The passed path is the full path to the file relative to the source
+directory.
+
+e.g.
+
+RecursiveCopy::copypath('/some/path', '/empty/dir',
+	filterfn => sub {^
+		# omit children of pg_log
+		my $src = shift;
+		return ! $src ~= /\/pg_log\//
+	}
+);
+
+=cut
+
 sub copypath
 {
-	my $srcpath  = shift;
-	my $destpath = shift;
+	my ($srcpath, $destpath, %params) = @_;
+
+	die("if specified, 'filterfn' must be a sub ref")
+	  if defined $params{filterfn} && !ref $params{filterfn};
+
+	my $filterfn;
+	if (defined $params{filterfn})
+	{
+		$filterfn = $params{filterfn};
+	}
+	else
+	{
+		$filterfn = sub { return 1; };
+	}
+
+	return _copypath_recurse($srcpath, $destpath, $filterfn);
+}
+
+# Recursive private guts of copypath
+sub _copypath_recurse
+{
+	my ($srcpath, $destpath, $filterfn) = @_;
 
 	die "Cannot operate on symlinks" if -l $srcpath or -l $destpath;
 
@@ -19,8 +79,11 @@ sub copypath
 	die "Destination path $destpath exists as file" if -f $destpath;
 	if (-f $srcpath)
 	{
-		copy($srcpath, $destpath)
-		  or die "copy $srcpath -> $destpath failed: $!";
+		if ($filterfn->($srcpath))
+		{
+			copy($srcpath, $destpath)
+			  or die "copy $srcpath -> $destpath failed: $!";
+		}
 		return 1;
 	}
 
@@ -32,7 +95,8 @@ sub copypath
 	while (my $entry = readdir($directory))
 	{
 		next if ($entry eq '.' || $entry eq '..');
-		RecursiveCopy::copypath("$srcpath/$entry", "$destpath/$entry")
+		RecursiveCopy::_copypath_recurse("$srcpath/$entry",
+			"$destpath/$entry", $filterfn)
 		  or die "copypath $srcpath/$entry -> $destpath/$entry failed";
 	}
 	closedir($directory);