From 37156a874b323be70719e3f7187dee487f1a698e Mon Sep 17 00:00:00 2001
From: Shawn Laffan <shawnlaffan@gmail.com>
Date: Tue, 21 May 2019 08:01:21 +1000
Subject: [PATCH 1/3] Add Dataset::GetLayerCount method

Also raise exceptions when invalid layers
are accessed via Dataset::GetLayer
---
 lib/Geo/GDAL/FFI/Dataset.pm | 16 +++++++++++++--
 t/dataset.t                 | 40 +++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 t/dataset.t

diff --git a/lib/Geo/GDAL/FFI/Dataset.pm b/lib/Geo/GDAL/FFI/Dataset.pm
index 9d6caef..aa463f4 100644
--- a/lib/Geo/GDAL/FFI/Dataset.pm
+++ b/lib/Geo/GDAL/FFI/Dataset.pm
@@ -92,11 +92,23 @@ sub GetBands {
     return @bands;
 }
 
+sub GetLayerCount {
+    my ($self) = @_;
+    return Geo::GDAL::FFI::GDALDatasetGetLayerCount($$self);
+}
+
+
 sub GetLayer {
     my ($self, $i) = @_;
     $i //= 0;
-    my $l = Geo::GDAL::FFI::isint($i) ? Geo::GDAL::FFI::GDALDatasetGetLayer($$self, $i) :
-    Geo::GDAL::FFI::GDALDatasetGetLayerByName($$self, $i);
+    my $l = Geo::GDAL::FFI::isint($i)
+      ? Geo::GDAL::FFI::GDALDatasetGetLayer($$self, $i)
+      : Geo::GDAL::FFI::GDALDatasetGetLayerByName($$self, $i);
+    unless ($l) {
+        my $msg = Geo::GDAL::FFI::error_msg()
+          // "Could not access layer $i in data set.";
+        confess $msg if $msg;
+    }
     Geo::GDAL::FFI::_register_parent_ref ($l, $self);
     return bless \$l, 'Geo::GDAL::FFI::Layer';
 }
diff --git a/t/dataset.t b/t/dataset.t
new file mode 100644
index 0000000..b0cda12
--- /dev/null
+++ b/t/dataset.t
@@ -0,0 +1,40 @@
+use v5.10;
+use strict;
+use warnings;
+use Carp;
+use Geo::GDAL::FFI qw/GetDriver HaveGEOS/;
+use Test::More;
+use Test::Exception;
+use Data::Dumper;
+
+my $ds = GetDriver('GPKG')->Create('test.gpkg');
+my $sr = Geo::GDAL::FFI::SpatialReference->new(EPSG => 3067);
+foreach my $i (1..3) {
+    my $l = $ds->CreateLayer({
+        Name => "test$i",
+        SpatialReference => $sr,
+        GeometryType => 'Point',
+    });
+    my $d = $l->GetDefn();
+    my $f = Geo::GDAL::FFI::Feature->new($d);
+    $l->CreateFeature($f);
+}
+
+
+is ($ds->GetLayerCount, 3, 'Got expected number of layers');
+
+dies_ok (
+    sub {$ds->GetLayer ('not_exists')},
+    'GetLayer exception for non-existent layer name',
+);
+dies_ok (
+    sub {$ds->GetLayer (23)},
+    'GetLayer exception for too large index',
+);
+dies_ok (
+    sub {$ds->GetLayer (-1)},
+    'GetLayer exception for negative index',
+);
+
+
+done_testing();

From 0186f2f2db95e295f3e0c1fbb1bde281730b6a13 Mon Sep 17 00:00:00 2001
From: Shawn Laffan <shawnlaffan@gmail.com>
Date: Tue, 21 May 2019 08:02:20 +1000
Subject: [PATCH 2/3] Add Test::Exception to TEST_REQUIRES

---
 Makefile.PL | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Makefile.PL b/Makefile.PL
index ea585ca..a1bae11 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -21,6 +21,7 @@ WriteMakefile(
     },
     TEST_REQUIRES => {
         'Test::More' => 0,
+        'Test::Exception' => 0,
         'JSON' => 0,
         'Data::Dumper' => 0
     },

From c36ee9960642ee21e285436ea7f201f19aad335a Mon Sep 17 00:00:00 2001
From: Shawn Laffan <shawnlaffan@gmail.com>
Date: Tue, 21 May 2019 08:05:33 +1000
Subject: [PATCH 3/3] Add POD for GetLayerCount

---
 lib/Geo/GDAL/FFI/Dataset.pm | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/Geo/GDAL/FFI/Dataset.pm b/lib/Geo/GDAL/FFI/Dataset.pm
index aa463f4..03e908b 100644
--- a/lib/Geo/GDAL/FFI/Dataset.pm
+++ b/lib/Geo/GDAL/FFI/Dataset.pm
@@ -516,6 +516,10 @@ SpatialReference are ignored.
 
 =back
 
+=head2 GetLayerCount
+ my $count = $dataset->GetLayerCount();
+
+
 =head2 GetLayer
 
  my $layer = $dataset->GetLayer($name);