Tidy up map browse code and qualify various global names to avoid

any risk of conflicts.

app/views/browse/_start.rhtml

@@ -1,12 +1,13 @@
-<div style="padding:0px 10px">
+<div style="padding: 0px 10px">
   <div style="text-align: center">
     <p style="margin-top: 10px">
-      <a id="use_map" display="hidden" href="#">View Data For Current Map View</a>
+      <a id="browse_select_view" href="#">View data for current map view</a>
       <br />
-      <a id='drag_box' href="#">Manually select a different area</a>  
+      <a id="browse_select_box" href="#">Manually select a different area</a>  
     </p>
-</div>
+  </div>
-<div id="status"></div>
+  <div id="browse_status">
-<div id="object">
+  </div>
-</div>
+  <div id="browse_object_list">
+  </div>
 </div>

app/views/browse/start.rjs

@@ -1,16 +1,25 @@
 page.replace_html :sidebar_title, 'Data'
 page.replace_html :sidebar_content, :partial => 'start'
 page << <<EOJ
+  var browseBoxControl;
+  var browseActive;
+  var browseMode = "auto";
+  var browseBounds;
+  var browseFeatureList;
+  var browseActiveFeature;
+  var browseDataLayer;
+  var browseSelectControl;
+  var browseObjectList;
 
-    var gml, sf, objList, currentFeature, featureList, mode = "auto", currentBounds, browsing;
   OpenLayers.Feature.Vector.style['default'].strokeWidth = 3;
   OpenLayers.Feature.Vector.style['default'].cursor = "pointer";
     
-    function start() {
+  function startBrowse() {
     openSidebar({ onclose: stopBrowse });
+
     var vectors = new OpenLayers.Layer.Vector();
     
-        box = new OpenLayers.Control.DrawFeature(vectors, OpenLayers.Handler.RegularPolygon, { 
+    browseBoxControl = new OpenLayers.Control.DrawFeature(vectors, OpenLayers.Handler.RegularPolygon, { 
       handlerOptions: {
         sides: 4,
         snapAngle: 90,
@@ -19,109 +28,133 @@ page << <<EOJ
         callbacks: { done: endDrag }
       }
     });
-        map.addControl(box);
+    map.addControl(browseBoxControl);
+
     map.events.register("moveend", map, showData);
     map.events.triggerEvent("moveend");
-        map.dataLayer.stopBrowse = stopBrowse;
+
-        browsing = true;
+    browseActive = true;
   }
 
   function showData() {
-        if (mode == "manual") { return; }
+    if (browseMode == "auto") {
       if (map.getZoom() >= 15) {
           useMap();
       } else {
-            $("status").innerHTML = "Zoom in or Select an area of the map to view.";
+          $("browse_status").innerHTML = "Zoom in or Select an area of the map to view.";
+      }    
     }
   }
 
   function stopBrowse() {
-        if (browsing) {
+    if (browseActive) {
-            browsing = false; 
+      browseActive = false;
-            map.dataLayer.stopBrowse = null;
+
-            if (gml) {
+      if (browseDataLayer) {
-                gml.destroy();
+        browseDataLayer.destroy();
-                gml = null; 
+        browseDataLayer = null; 
       } 
-            if (sf) {   
+
-                sf.destroy();  
+      if (browseSelectControl) {   
-                sf = null;
+        browseSelectControl.destroy();  
+        browseSelectControl = null;
       } 
-	    if (box) {
+
-	    	box.destroy();
+      if (browseBoxControl) {
-		box = null;
+    	browseBoxControl.destroy();
+	browseBoxControl = null;
       }		
-            if (currentFeature) {
+
-                currentFeature.destroy(); 
+      if (browseActiveFeature) {
-                currentFeature = null; 
+        browseActiveFeature.destroy(); 
+        browseActiveFeature = null; 
       }
+
       map.dataLayer.setVisibility(false);
       map.events.unregister("moveend", map, showData);
     }    
   }
     
   function startDrag() {
-      $("drag_box").innerHTML='Drag a box on the map to select an area';
+    $("browse_select_box").innerHTML='Drag a box on the map to select an area';
-       box.activate(); 
+
+    browseBoxControl.activate();
+
     return false;
   };
-    $("drag_box").onclick = startDrag;
+
+  $("browse_select_box").onclick = startDrag;
     
   function useMap() {
     var bounds = map.getExtent();
     var projected = bounds.clone().transform(map.getProjectionObject(), epsg4326);
-        if (!currentBounds || !currentBounds.containsBounds(projected)) {
+
+    if (!browseBounds || !browseBounds.containsBounds(projected)) {
       var center = bounds.getCenterLonLat();
       var tileWidth = bounds.getWidth() * 1.2;
       var tileHeight = bounds.getHeight() * 1.2;
-            var tileBounds =
+      var tileBounds = new OpenLayers.Bounds(center.lon - (tileWidth / 2),
-                new OpenLayers.Bounds(center.lon - (tileWidth / 2),
                                              center.lat - (tileHeight / 2),
                                              center.lon + (tileWidth / 2),
                                              center.lat + (tileHeight / 2));
 
-            currentBounds = tileBounds;
+      browseBounds = tileBounds;
       getData(tileBounds);
-            mode = "auto";
+
-            $("use_map").style.display="none";
+      browseMode = "auto";
+
+      $("browse_select_view").style.display = "none";
     }
+
     return false;
   }
-    $("use_map").onclick = useMap;
+
+  $("browse_select_view").onclick = useMap;
     
   function endDrag(bbox) {
     var bounds = bbox.getBounds();
-        box.deactivate();
+    var projected = bounds.clone().transform(map.getProjectionObject(), epsg4326);
-        currentBounds = bounds;
+
+    browseBoxControl.deactivate();
+    browseBounds = projected;
     getData(bounds);
-        $("drag_box").innerHTML = "Manually select a different area";
+
-        mode = "manual";  
+    browseMode = "manual";  
-        $("use_map").style.display="inline";
+
+    $("browse_select_box").innerHTML = "Manually select a different area";
+    $("browse_select_view").style.display = "inline";
   }
     
   function displayFeatureWarning() {
-        $("status").innerHTML = "";
+    $("browse_status").innerHTML = "";
+
     var div = document.createElement("div");
+
     var p = document.createElement("p");
-        p.appendChild(document.createTextNode("You have loaded an area which contains " + featureList.length + " features. In general, some browsers may not cope well with displaying this quantity of data. Generally, browsers work best at displaying less than 100 features at a time: doing anything else may make your browser slow/unresponsive. If you are sure you want to display this data, you may do so by clicking the button below.")); 
+    p.appendChild(document.createTextNode("You have loaded an area which contains " + browseFeatureList.length + " features. In general, some browsers may not cope well with displaying this quantity of data. Generally, browsers work best at displaying less than 100 features at a time: doing anything else may make your browser slow/unresponsive. If you are sure you want to display this data, you may do so by clicking the button below."));
     div.appendChild(p);
+
     var input = document.createElement("input");
     input.type = "submit";
     input.value = "Load Data";
     input.onclick = loadFeatureList;
     div.appendChild(input); 
-        $("object").innerHTML="";
+
-        $("object").appendChild(div);
+    $("browse_object_list").innerHTML = "";
+    $("browse_object_list").appendChild(div);
   }
     
   function loadFeatureList() {
-        gml.addFeatures(featureList);
+    browseDataLayer.addFeatures(browseFeatureList);
-        gml.events.triggerEvent("loadend");
+    browseDataLayer.events.triggerEvent("loadend");
+
+    browseFeatureList = []; 
+
     return false;
   }    
 
   function customDataLoader(request) { 
-        if (!browsing) { return; } 
+    if (browseActive) {
       var doc = request.responseXML;
 
       if (!doc || !doc.documentElement) {
@@ -131,88 +164,93 @@ page << <<EOJ
       var options = {};
 
       OpenLayers.Util.extend(options, this.formatOptions);
+
       if (this.map && !this.projection.equals(this.map.getProjectionObject())) {
         options.externalProjection = this.projection;
         options.internalProjection = this.map.getProjectionObject();
       }    
 
       var gml = this.format ? new this.format(options) : new OpenLayers.Format.GML(options);
-        var features = gml.read(doc);
+
-        if (!this.maxFeatures || features.length <= this.maxFeatures) {
+      browseFeatureList = gml.read(doc);
-            this.addFeatures(features);
+
-            this.events.triggerEvent("loadend");
+      if (!this.maxFeatures || browseFeatureList.length <= this.maxFeatures) {
-            featureList = []; 
+        loadFeatureList();
       } else {
-            featureList = features;
         displayFeatureWarning();
       }
     }
+  }
 
   function getData(bounds) {
+    var projected = bounds.clone().transform(new OpenLayers.Projection("EPSG:900913"), new OpenLayers.Projection("EPSG:4326"));
+    var size = projected.getWidth() * projected.getHeight();
 
-        bounds.transform(new OpenLayers.Projection("EPSG:900913"), new OpenLayers.Projection("EPSG:4326"));
-        var size = bounds.getWidth() * bounds.getHeight(); 
     if (size > 0.25) {
-            $("status").innerHTML = "Unable to load: Bounding box size of " + size + " is too large. (Must be smaller than 0.25)<br />"; 
+      $("browse_status").innerHTML = "Unable to load: Bounding box size of " + size + " is too large. (Must be smaller than 0.25)<br />";
-            return;
-        }
-
-        var url = "/api/0.5/map?bbox="+bounds.toBBOX();
-        
-        loadGML(url);
-    }
-    function loadGML(url) {
-        $("status").innerHTML = "Loading...";
-        $("object").innerHTML = "";
-        if (!gml) {
-            var style = new OpenLayers.Style();
-            style.addRules([new OpenLayers.Rule( 
-              {'symbolizer': 
-                {"Polygon": {'fillColor': '#ff0000', 'strokeColor': '#ff0000'},
-                 "Line": {'fillColor': '#ffff00', 'strokeColor': '#000000', strokeOpacity: '0.4'},
-                 "Point": {'fillColor': '#00ff00', 'strokeColor': '#00ff00'}}
-              }
-            )]);
-            gml = new OpenLayers.Layer.GML("Data",url, 
-                    {format: OpenLayers.Format.OSM, formatOptions: {checkTags: true},
-                     maxFeatures: 100, requestSuccess: customDataLoader,
-                     displayInLayerSwitcher: false,
-                     styleMap: new OpenLayers.StyleMap({'default': style, 'select': {'strokeColor': '#0000ff', strokeWidth: 8}})
-                    }
-            );
-            gml.events.register("loadend", gml, dataLoaded );
-            map.addLayer(gml);
-            
-            sf = new OpenLayers.Control.SelectFeature(gml, {'onSelect': onFeatureSelect});
-            sf.handler.stopDown = false;
-            sf.handler.stopUp = false;
-            map.addControl(sf);
-            sf.activate();
-             
     } else {
-            gml.setUrl(url);
+      loadGML("/api/0.5/map?bbox=" + projected.toBBOX());
+    }
   }
 
-        currentFeature = null;
+  function loadGML(url) {
+    $("browse_status").innerHTML = "Loading...";
+    $("browse_object_list").innerHTML = "";
+
+    if (!browseDataLayer) {
+      var style = new OpenLayers.Style();
+
+      style.addRules([new OpenLayers.Rule({
+        symbolizer: {
+          Polygon: { fillColor: '#ff0000', strokeColor: '#ff0000' },
+          Line: { fillColor: '#ffff00', strokeColor: '#000000', strokeOpacity: '0.4' },
+          Point: { fillColor: '#00ff00', strokeColor: '#00ff00' }
         }
+      })]);
+
+      browseDataLayer = new OpenLayers.Layer.GML("Data", url, {
+        format: OpenLayers.Format.OSM,
+        formatOptions: { checkTags: true },
+        maxFeatures: 100,
+        requestSuccess: customDataLoader,
+        displayInLayerSwitcher: false,
+        styleMap: new OpenLayers.StyleMap({
+          default: style,
+          select: { strokeColor: '#0000ff', strokeWidth: 8 }
+        })
+      });
+      browseDataLayer.events.register("loadend", browseDataLayer, dataLoaded );
+      map.addLayer(browseDataLayer);
+            
+      browseSelectControl = new OpenLayers.Control.SelectFeature(browseDataLayer, { onSelect: onFeatureSelect });
+      browseSelectControl.handler.stopDown = false;
+      browseSelectControl.handler.stopUp = false;
+      map.addControl(browseSelectControl);
+      browseSelectControl.activate();
+    } else {
+      browseDataLayer.setUrl(url);
+    }
+
+    browseActiveFeature = null;
+  }
+
   function dataLoaded() {
-        if (!browsing) { return; } 
+    if (browseActive) {
-        $("status").innerHTML = "Loaded."
+      $("browse_status").innerHTML = "Loaded."
         
-        objList = document.createElement("div")
+      var list = document.createElement("ul");
 
-        list = document.createElement("ul");
       for (var i = 0; i < this.features.length; i++) {
         var feature = this.features[i]; 
             
         // Type, for linking
-            var type ="way";
+        var type = "way";
         if (feature.geometry.CLASS_NAME == "OpenLayers.Geometry.Point") {
           type = "node";
         } 
-            var nice_name = type.substr(0,1).toUpperCase() + type.substr(1,type.length); 
+        var typeName = type.substr(0,1).toUpperCase() + type.substr(1,type.length); 
         var li = document.createElement("li");
-            li.appendChild(document.createTextNode(nice_name + " "));
+        li.appendChild(document.createTextNode(typeName + " "));
             
         // Link, for viewing in the tab
         var link = document.createElement("a");
@@ -225,40 +263,50 @@ page << <<EOJ
 
         list.appendChild(li);
       }
-        objList.appendChild(list)
+
+      browseObjectList = document.createElement("div")
+      browseObjectList.appendChild(list)
+
       var link = document.createElement("a");
       link.href = this.url;
       link.appendChild(document.createTextNode("API"));
-        objList.appendChild(link)
+      browseObjectList.appendChild(link);
-        $("object").innerHTML = "";
-        $("object").appendChild(objList); 
 
+      $("browse_object_list").innerHTML = "";
+      $("browse_object_list").appendChild(browseObjectList); 
+    }
   }
     
   function viewFeatureLink() {
     var layer = this.feature.layer;
+
     for (var i = 0; i < layer.selectedFeatures.length; i++) {
       var f = layer.selectedFeatures[i]; 
       layer.drawFeature(f, layer.styleMap.createSymbolizer(f, "default"));
     }
+
     onFeatureSelect(this.feature);
-        if (mode != "auto") {
+
+    if (browseMode != "auto") {
       map.setCenter(this.feature.geometry.getBounds().getCenterLonLat()); 
     }
+
     return false;
   }
     
-    function loadObjList() {
+  function loadObjectList() {
-        $("object").innerHTML="";
+    $("browse_object_list").innerHTML="";
-        $("object").appendChild(objList);
+    $("browse_object_list").appendChild(browseObjectList);
+
     return false;
   }
       
   function onFeatureSelect(feature) {
     // Unselect previously selected feature
-        if (currentFeature) {
+    if (browseActiveFeature) {
-          currentFeature.layer.drawFeature(
+      browseActiveFeature.layer.drawFeature(
-            currentFeature, currentFeature.layer.styleMap.createSymbolizer(currentFeature, "default")
+        browseActiveFeature, 
+        browseActiveFeature.layer.styleMap.createSymbolizer(browseActiveFeature, "default")
       );
     }
 
@@ -267,21 +315,23 @@ page << <<EOJ
       feature, feature.layer.styleMap.createSymbolizer(feature, "select")
     );
 
-        // If the current object is the list, don't innerHTML="", since that could clar it.   
+    // If the current object is the list, don't innerHTML="", since that could clear it.
-        if ($("object").firstChild == objList) { 
+    if ($("browse_object_list").firstChild == browseObjectList) { 
-            $("object").removeChild(objList);
+      $("browse_object_list").removeChild(browseObjectList);
     } else { 
-            $("object").innerHTML = "";
+      $("browse_object_list").innerHTML = "";
     }   
         
     // Create a link back to the object list
-        var div = document.createElement("div");
     var link = document.createElement("a");
-        link.href="#";
+    link.href = "#";
-        link.onclick = loadObjList;
+    link.onclick = loadObjectList;
     link.appendChild(document.createTextNode("Back to Object List"));
+
+    var div = document.createElement("div");
     div.appendChild(link)
-        $("object").appendChild(div);    
+
+    $("browse_object_list").appendChild(div);    
         
     var type = "way";
     if (feature.geometry.CLASS_NAME == "OpenLayers.Geometry.Point") {
@@ -289,14 +339,14 @@ page << <<EOJ
     }    
         
     var link = document.createElement("a");   
-        link.href =  "/browse/"+type+"/"+feature.osm_id;
+    link.href = "/browse/" + type + "/" + feature.osm_id;
     link.appendChild(document.createTextNode("Database entry for " + feature.osm_id));
         
     var div = document.createElement("div");
     div.style.marginTop = "20px"
     div.appendChild(link);
 
-        $("object").appendChild(div);
+    $("browse_object_list").appendChild(div);
 
     // Now the list of attributes
     var ul = document.createElement("ul");
@@ -309,35 +359,45 @@ page << <<EOJ
       ul.appendChild(li);
     }
         
-        $("object").appendChild(ul);
+    $("browse_object_list").appendChild(ul);
         
     var link = document.createElement("a");   
     link.href =  "/browse/"+type+"/"+feature.osm_id+"/history";
     link.appendChild(document.createTextNode("History"));
-        ul.appendChild(li);
+    link.onclick = OpenLayers.Function.bind(loadHistory, {
-        link.onclick = OpenLayers.Function.bind(loadHistory, {type: type, feature: feature, link: link});
+      type: type, feature: feature, link: link
+    });
         
-        $("object").appendChild(link);
+    $("browse_object_list").appendChild(link);
 
     // Stash the currently drawn feature
-        currentFeature = feature; 
+    browseActiveFeature = feature; 
   }   
+
   function loadHistory() {
     this.link.href = "";
     this.link.innerHTML = "Wait...";
-        new Ajax.Request("/api/0.5/"+this.type+"/"+this.feature.osm_id+"/history", {onComplete: OpenLayers.Function.bind(displayHistory, this)});
+
+    new Ajax.Request("/api/0.5/" + this.type + "/" + this.feature.osm_id + "/history", {
+      onComplete: OpenLayers.Function.bind(displayHistory, this)
+    });
+
     return false;
   }
+
   function displayHistory(request) {
-        if (currentFeature.osm_id != this.feature.osm_id || $("object").firstChild == objList)  { 
+    if (browseActiveFeature.osm_id != this.feature.osm_id || $("browse_object_list").firstChild == browseObjectList)  { 
         return false;
     } 
+
     this.link.parentNode.removeChild(this.link);
+
     var doc = request.responseXML;
     var div = document.createElement("div");
     var h3 = document.createElement("h3"); 
     h3.appendChild(document.createTextNode("History"));
     div.appendChild(h3);
+
     var nodes = doc.getElementsByTagName(this.type);
     var history = document.createElement("ul");  
     for (var i = nodes.length - 1; i >= 0; i--) {
@@ -348,12 +408,14 @@ page << <<EOJ
       history.appendChild(item);
     }
     div.appendChild(history);
+
     var link = document.createElement("a");
     link.appendChild(document.createTextNode("History entry for " + this.feature.osm_id));
     link.href = "/browse/"+this.type+"/"+this.feature.osm_id+"/history";
     div.appendChild(link);
-        $("object").appendChild(div); 
+
+    $("browse_object_list").appendChild(div); 
   }
     
-    start();
+  startBrowse();
 EOJ