Added a new extension point called "PageDecorator" to add HTML fragments to all pages.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@11223 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Functions.java

@@ -17,6 +17,7 @@ import hudson.model.Project;
 import hudson.model.Run;
 import hudson.model.TopLevelItem;
 import hudson.model.View;
+import hudson.model.PageDecorator;
 import hudson.search.SearchableModelObject;
 import hudson.security.AccessControlled;
 import hudson.security.AuthorizationStrategy;
@@ -932,5 +933,12 @@ public class Functions {
         return null;
     }
 
+    /**
+     * Gets all the {@link PageDecorator}s.
+     */
+    public static List<PageDecorator> getPageDecorators() {
+        return (List)PageDecorator.ALL;
+    }
+
     private static final Pattern SCHEME = Pattern.compile("[a-z]+://.+");
 }

core/src/main/java/hudson/model/PageDecorator.java

+package hudson.model;
+
+import hudson.ExtensionPoint;
+import hudson.Plugin;
+import hudson.util.DescriptorList;
+
+/**
+ * Participates in the rendering of HTML pages for all pages of Hudson.
+ *
+ * <p>
+ * This class provides a few hooks to augument the HTML generation process of Hudson, across
+ * all the HTML pages that Hudson delivers.
+ *
+ * <p>
+ * For example, if you'd like to add a Google Analytics stat to Hudson, then you need to inject
+ * a small script fragment to all Hudson pages. This extension point provides a means to do that.
+ *
+ * <h2>Life-cycle</h2>
+ * <p>
+ * Instances of this class is singleton. {@link Plugin}s that contribute this extension point
+ * should instantiate a new decorator and add it to the {@link #ALL} list in {@link Plugin#start()}. 
+ *
+ * <h2>Associated Views</h2>
+ * <h4>global.jelly</h4>
+ * <p>
+ * If this extension point needs to expose a global configuration, write this jelly page.
+ * See {@link Descriptor} for more about this. Optional.
+ *
+ * <h4>footer.jelly</h4>
+ * <p>
+ * This page is added right before the &lt;/body> tag. Convenient place for adding tracking beacons, etc.
+ *
+ * <h4>header.jelly</h4>
+ * <p>
+ * This page is added right before the &lt;/head> tag. Convenient place for additional stylesheet,
+ * &lt;meta> tags, etc.
+ *
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.235
+ */
+public abstract class PageDecorator extends Descriptor<PageDecorator> implements ExtensionPoint, Describable<PageDecorator> {
+    /**
+     * @param yourClass
+     *      pass-in "this.getClass()" (except that the constructor parameters cannot use 'this',
+     *      so you'd have to hard-code the class name.
+     */
+    protected PageDecorator(Class<? extends PageDecorator> yourClass) {
+        super(yourClass);
+    }
+
+    public final Descriptor<PageDecorator> getDescriptor() {
+        return this;
+    }
+
+    /**
+     * Unless this object has additional web presence, display name is not used at all.
+     * So default to "".
+     */
+    public String getDisplayName() {
+        return "";
+    }
+
+    /**
+     * All the registered instances.
+     */
+    public static final DescriptorList<PageDecorator> ALL = new DescriptorList<PageDecorator>();
+}

core/src/main/java/hudson/model/UpdateCenter.java

@@ -513,6 +513,19 @@ public class UpdateCenter implements ModelObject {
         }
     }
 
+    /**
+     * Adds the update center data retriever to HTML.
+     */
+    public static class PageDecoratorImpl extends PageDecorator {
+        public PageDecoratorImpl() {
+            super(PageDecoratorImpl.class);
+        }
+    }
+
+    static {
+        PageDecorator.ALL.add(new PageDecoratorImpl());
+    }
+
     /**
      * Sequence number generator.
      */

core/src/main/resources/hudson/model/UpdateCenter/PageDecoratorImpl/footer.jelly

+<!--
+  If necessary, ask the client to fetch update-center data file for us.
+  This allows us to avoid proxy related configuration on the server,
+  and instead piggy-back on user connection.
+
+  This file is pulled into the layout.jelly
+-->
+<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
+  <j:if test="${app.updateCenter.due or forcedUpdateCheck}">
+    <script>
+      updateCenter.postBackURL = "${rootURL}/updateCenter/postBack";
+      updateCenter.version = "${h.version}"; 
+      Behaviour.addLoadEvent(updateCenter.checkUpdates);
+    </script>
+  </j:if>
+</j:jelly>
\ No newline at end of file

core/src/main/resources/lib/layout/layout.jelly

@@ -74,6 +74,9 @@
     <meta name="ROBOTS" content="INDEX,NOFOLLOW" />
     <j:set var="mode" value="header" />
     <d:invokeBody />
+    <j:forEach var="pd" items="${h.pageDecorators}">
+      <st:include it="${pd}" page="header.jelly" optional="true" />
+    </j:forEach>
   </head>
   <body class="yui-skin-sam">
     <table id="header" cellpadding="0" cellspacing="0" width="100%" border="0">
@@ -176,6 +179,9 @@
     </table>
     <!-- during the loading 'app' object is not Hudson, so it may not have update center -->
     <st:include it="${app.updateCenter}" page="main.jelly" optional="true" />
+    <j:forEach var="pd" items="${h.pageDecorators}">
+      <st:include it="${pd}" page="footer.jelly" optional="true" />
+    </j:forEach>
   </body>
 </html>
 </j:jelly>
\ No newline at end of file