Add Appearance system configuration page (#8403)

* Add `Appearance` system configuration page

* Use one-column layout

* Add developer guidance

core/src/main/java/jenkins/appearance/AppearanceCategory.java

@@ -0,0 +1,53 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2023, Tim Jacomb
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.appearance;
+
+import hudson.Extension;
+import jenkins.model.GlobalConfigurationCategory;
+
+/**
+ * <p>Global configuration of appearance configuration.</p>
+ *
+ * <p>This should be used for Plugins that contribute to the look and feel of Jenkins.
+ * Theming, header and footer changes, information density are all good examples.
+ * API plugins for UI components that are used by other plugins also fit into that, e.g. source code display.</p>
+ *
+ * <p>Configuration specific to a single plugin that is not related to the overall look and feel of Jenkins may not belong here.</p>
+ *
+ * <p>If a plugin has a single global configuration it should separate appearance and general configuration to different classes.</p>
+ *
+ */
+@Extension
+public class AppearanceCategory extends GlobalConfigurationCategory {
+    @Override
+    public String getShortDescription() {
+        return Messages.AppearanceCategory_DisplayName();
+    }
+
+    @Override
+    public String getDisplayName() {
+        return Messages.AppearanceCategory_Description();
+    }
+}

core/src/main/java/jenkins/appearance/AppearanceGlobalConfiguration.java

@@ -0,0 +1,110 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2023, Tim Jacomb
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.appearance;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+import hudson.Extension;
+import hudson.Functions;
+import hudson.model.Descriptor;
+import hudson.model.ManagementLink;
+import hudson.util.FormApply;
+import java.io.IOException;
+import java.util.function.Predicate;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import javax.servlet.ServletException;
+import jenkins.model.Jenkins;
+import net.sf.json.JSONObject;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
+import org.kohsuke.stapler.StaplerRequest;
+import org.kohsuke.stapler.StaplerResponse;
+import org.kohsuke.stapler.verb.POST;
+
+@Extension
+public class AppearanceGlobalConfiguration extends ManagementLink {
+
+    private static final Logger LOGGER = Logger.getLogger(AppearanceGlobalConfiguration.class.getName());
+
+    @Restricted(NoExternalUse.class)
+    public static final Predicate<Descriptor> FILTER = input -> input.getCategory() instanceof AppearanceCategory;
+
+    @Override
+    public String getIconFileName() {
+        if (Functions.getSortedDescriptorsForGlobalConfigByDescriptor(FILTER).isEmpty()) {
+            return null;
+        }
+
+        return "symbol-brush-outline";
+    }
+
+    @Override
+    public String getDisplayName() {
+        return Messages.AppearanceGlobalConfiguration_DisplayName();
+    }
+
+    @Override
+    public String getDescription() {
+        return Messages.AppearanceGlobalConfiguration_Description();
+    }
+
+    @Override
+    public String getUrlName() {
+        return "appearance";
+    }
+
+    @NonNull
+    @Override
+    public Category getCategory() {
+        return Category.CONFIGURATION;
+    }
+
+    @POST
+    public synchronized void doConfigure(StaplerRequest req, StaplerResponse rsp) throws IOException, ServletException, Descriptor.FormException {
+        boolean result = configure(req, req.getSubmittedForm());
+        LOGGER.log(Level.FINE, "appearance saved: " + result);
+        FormApply.success(req.getContextPath() + "/manage").generateResponse(req, rsp, null);
+    }
+
+    private boolean configure(StaplerRequest req, JSONObject json) throws Descriptor.FormException, IOException {
+        Jenkins j = Jenkins.get();
+        j.checkPermission(Jenkins.MANAGE);
+
+        boolean result = true;
+        for (Descriptor<?> d : Functions.getSortedDescriptorsForGlobalConfigByDescriptor(FILTER)) {
+            result &= configureDescriptor(req, json, d);
+        }
+        j.save();
+
+        return result;
+    }
+
+    private boolean configureDescriptor(StaplerRequest req, JSONObject json, Descriptor<?> d) throws Descriptor.FormException {
+        String name = d.getJsonSafeClassName();
+        JSONObject js = json.has(name) ? json.getJSONObject(name) : new JSONObject(); // if it doesn't have the property, the method returns invalid null object.
+        json.putAll(js);
+        return d.configure(req, js);
+    }
+}

core/src/main/resources/jenkins/appearance/AppearanceGlobalConfiguration/index.jelly

@@ -0,0 +1,61 @@
+<!--
+The MIT License
+
+Copyright (c) 2023, Tim Jacomb
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+-->
+
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:l="/lib/layout" xmlns:f="/lib/form">
+  <l:layout title="${%Appearance}" permissions="${app.MANAGE_AND_SYSTEM_READ}" type="one-column">
+    <j:set var="readOnlyMode" value="${!app.hasPermission(app.MANAGE)}"/>
+    <l:main-panel>
+      <l:app-bar title="${%Appearance}"/>
+
+      <div class="behavior-loading">
+        <l:spinner text="${%Loading}"/>
+      </div>
+
+      <f:form method="post" name="config" action="configure" class="jenkins-form">
+        <j:set var="instance" value="${it}" />
+        <j:set var="descriptor" value="${instance.descriptor}" />
+
+        <j:forEach var="descriptor" items="${h.getSortedDescriptorsForGlobalConfigByDescriptor(it.FILTER)}">
+          <j:set var="instance" value="${descriptor}" />
+          <f:rowSet name="${descriptor.jsonSafeClassName}">
+            <st:include page="${descriptor.globalConfigPage}" from="${descriptor}" />
+          </f:rowSet>
+        </j:forEach>
+
+        <l:hasAdministerOrManage>
+          <f:bottomButtonBar>
+            <f:submit value="${%Save}" />
+            <f:apply />
+          </f:bottomButtonBar>
+        </l:hasAdministerOrManage>
+      </f:form>
+
+      <l:hasAdministerOrManage>
+        <st:adjunct includes="lib.form.confirm" />
+      </l:hasAdministerOrManage>
+
+    </l:main-panel>
+  </l:layout>
+</j:jelly>

core/src/main/resources/jenkins/appearance/Messages.properties

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+AppearanceGlobalConfiguration.DisplayName=Appearance
+AppearanceGlobalConfiguration.Description=Configure the look and feel of Jenkins
+
+AppearanceCategory.DisplayName=Appearance
+AppearanceCategory.Description=Configure the look and feel of Jenkins