From be78202e0bcf462861c8c7150d8e68e089719f6d Mon Sep 17 00:00:00 2001
From: Young Hahn <young@developmentseed.org>
Date: Thu, 21 Feb 2013 15:29:33 -0500
Subject: [PATCH] Allow layers to be rendered without datasources.

---
 lib/carto/tree/layer.js                  |  4 +++-
 test/rendering/layer_nodatasource.mml    | 10 ++++++++++
 test/rendering/layer_nodatasource.mss    |  4 ++++
 test/rendering/layer_nodatasource.result | 17 +++++++++++++++++
 test/support/helper.js                   |  1 +
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 test/rendering/layer_nodatasource.mml
 create mode 100644 test/rendering/layer_nodatasource.mss
 create mode 100644 test/rendering/layer_nodatasource.result

diff --git a/lib/carto/tree/layer.js b/lib/carto/tree/layer.js
index 5e33ef6..713c77a 100644
--- a/lib/carto/tree/layer.js
+++ b/lib/carto/tree/layer.js
@@ -20,9 +20,11 @@ tree.LayerXML = function(obj, styles) {
         styles.reverse().map(function(s) {
             return '<StyleName>' + s + '</StyleName>';
         }).join('\n    ') +
+        (dsoptions.length ?
         '\n    <Datasource>\n       ' +
         dsoptions.join('\n       ') +
-        '\n    </Datasource>\n' +
+        '\n    </Datasource>\n'
+        : '') +
         '  </Layer>\n';
 };
 
diff --git a/test/rendering/layer_nodatasource.mml b/test/rendering/layer_nodatasource.mml
new file mode 100644
index 0000000..01eadc0
--- /dev/null
+++ b/test/rendering/layer_nodatasource.mml
@@ -0,0 +1,10 @@
+{
+    "srs": "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over",
+    "Stylesheet": [
+        "layer_nodatasource.mss"
+    ],
+    "Layer": [{
+        "name": "world",
+        "srs": "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over"
+    }]
+}
diff --git a/test/rendering/layer_nodatasource.mss b/test/rendering/layer_nodatasource.mss
new file mode 100644
index 0000000..249df79
--- /dev/null
+++ b/test/rendering/layer_nodatasource.mss
@@ -0,0 +1,4 @@
+#world {
+  polygon-fill: green;
+  line-color: hsl(30, 40%, 90%);
+}
diff --git a/test/rendering/layer_nodatasource.result b/test/rendering/layer_nodatasource.result
new file mode 100644
index 0000000..3e78bad
--- /dev/null
+++ b/test/rendering/layer_nodatasource.result
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE Map[]>
+<Map srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over"  maximum-extent="-20037508.34,-20037508.34,20037508.34,20037508.34">
+
+
+<Style name="world" filter-mode="first">
+  <Rule>
+    <PolygonSymbolizer fill="#008000" />
+    <LineSymbolizer stroke="#f0e6db" />
+  </Rule>
+</Style>
+<Layer name="world"
+   srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
+    <StyleName>world</StyleName>
+  </Layer>
+
+</Map>
diff --git a/test/support/helper.js b/test/support/helper.js
index 58a6873..4519978 100644
--- a/test/support/helper.js
+++ b/test/support/helper.js
@@ -195,6 +195,7 @@ helper.removeAbsoluteImages = function(xml) {
 helper.removeAbsoluteDatasources = function(xml) {
     xml.Map.forEach(function(map) {
         if (map.Layer) map.Layer.forEach(function(layer) {
+            if (!layer.Datasource) return;
             layer.Datasource.forEach(function(datasource) {
                 datasource.Parameter.forEach(function(param) {
                     if (param.name === 'file') {