From e0c26559f3012d356503bfe68ebc1fecd6f4b552 Mon Sep 17 00:00:00 2001
From: Andy Street <andy@street.me.uk>
Date: Wed, 19 Dec 2018 18:48:47 +0000
Subject: [PATCH] Add extensions for GPX type

---
 docs/samples/full-1.0.gpx |  1 +
 docs/samples/full-1.1.gpx |  3 +++
 src/libgpx/gpx.php        | 20 ++++++++++++++++++++
 src/libgpx/gpxreader.php  |  7 +++++++
 src/libgpx/gpxwriter.php  | 10 ++++++++++
 5 files changed, 41 insertions(+)

diff --git a/docs/samples/full-1.0.gpx b/docs/samples/full-1.0.gpx
index ab9c5f6..86381c5 100644
--- a/docs/samples/full-1.0.gpx
+++ b/docs/samples/full-1.0.gpx
@@ -61,4 +61,5 @@
       <trkpt lat="3.0" lon="3.0"/>
     </trkseg>
   </trk>
+  <custom:checkedBy>Jane Doe</custom:checkedBy>
 </gpx>
diff --git a/docs/samples/full-1.1.gpx b/docs/samples/full-1.1.gpx
index 414a45c..a061ed8 100644
--- a/docs/samples/full-1.1.gpx
+++ b/docs/samples/full-1.1.gpx
@@ -95,4 +95,7 @@
       <trkpt lat="3.0" lon="3.0"/>
     </trkseg>
   </trk>
+  <extensions>
+    <custom:checkedBy>Jane Doe</custom:checkedBy>
+  </extensions>
 </gpx>
diff --git a/src/libgpx/gpx.php b/src/libgpx/gpx.php
index f71f7f1..61e9e58 100644
--- a/src/libgpx/gpx.php
+++ b/src/libgpx/gpx.php
@@ -120,6 +120,13 @@ class GPX implements Geographic
    */
   protected $tracks;
 
+  /**
+   * A list of XML snippets describing unsupported elements.
+   *
+   * @var TypedDoublyLinkedList (string)
+   */
+  protected $extensions;
+
   /**
    * Fetch the name of the program that created the GPX file.
    *
@@ -323,6 +330,19 @@ class GPX implements Geographic
     return $this->tracks;
   }
 
+  /**
+   * Fetch a list of protocol extensions as raw XML.
+   *
+   * @param boolean $create Create the list if it does not already exist.
+   * @return TypedDoublyLinkedList A list of protocol extensions.
+   */
+  public function getExtensions(bool $create = true)
+  {
+    if ($create && $this->extensions === null)
+      $this->extensions = new TypedDoublyLinkedList('string');
+    return $this->extensions;
+  }
+
   /**
    * Fetch a bounding box that covers the feature.
    *
diff --git a/src/libgpx/gpxreader.php b/src/libgpx/gpxreader.php
index 4df8d1d..8e9c615 100644
--- a/src/libgpx/gpxreader.php
+++ b/src/libgpx/gpxreader.php
@@ -193,6 +193,9 @@ class GPXReader
       $struct['elements']['metadata'] = function ($gpx) {
         $this->readMetadata($gpx);
       };
+      $struct['elements']['extensions'] = function ($gpx) {
+        $this->readExtension($gpx->getExtensions());
+      };
     } else {
       $struct['elements']['name'] = function ($gpx) {
         $gpx->setName($this->readXSDString());
@@ -249,6 +252,10 @@ class GPXReader
           $keywords[] = trim($word);
       };
       $struct['elements']['bounds'] = false;
+      $struct['extensions'] = function ($gpx) {
+        $gpx->getExtensions()[] = $this->xml->readOuterXML();
+        $this->xml->next();
+      };
     }
 
     $this->readStruct($struct, $result);
diff --git a/src/libgpx/gpxwriter.php b/src/libgpx/gpxwriter.php
index 1e7878c..567a771 100644
--- a/src/libgpx/gpxwriter.php
+++ b/src/libgpx/gpxwriter.php
@@ -251,6 +251,16 @@ class GPXWriter
         $this->writeTrack($track, $xml);
       }
     }
+    $extensions = $gpx->getExtensions(false);
+    if ($extensions !== null && !$extensions->isEmpty()) {
+      if ($this->format == '1.1')
+        $xml->startElement('extensions');
+      foreach ($extensions as $extension) {
+        $xml->writeRaw($extension);
+      }
+      if ($this->format == '1.1')
+        $xml->endElement();
+    }
     $xml->endElement();
     $xml->endDocument();
     $xml->flush();
-- 
2.39.5