[FIXED JENKINS-18364] Functions.getRelativeLinkTo is called many time…

…s during rendering, so skip checking View.getItems which is expensive.

(cherry picked from commit bcc8614)

changelog.html

@@ -55,7 +55,9 @@
<!-- Record your changes in the trunk here. -->
<div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
<ul class=image>
  <li class=>
  <li class=bug>
    Faster rendering of views containing many items.
    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-18364">issue 18364</a>)
</ul>
</div><!--=TRUNK-END=-->

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

@@ -1014,20 +1014,15 @@ public static String getRelativeLinkTo(Item p) {

        Item i=p;
        String url = "";
        Collection<TopLevelItem> viewItems;
        if (view != null) {
            viewItems = view.getItems();
        } else {
            viewItems = Collections.emptyList();
        }
        while(true) {
            ItemGroup ig = i.getParent();
            url = i.getShortUrl()+url;

            if(ig== Jenkins.getInstance() || (view != null && ig == view.getOwnerItemGroup())) {
                assert i instanceof TopLevelItem;
                if(viewItems.contains((TopLevelItem)i)) {
                    // if p and the current page belongs to the same view, then return a relative path
                if (view != null) {
                    // assume p and the current page belong to the same view, so return a relative path
                    // (even if they did not, View.getItem does not by default verify ownership)
                    return normalizeURI(ancestors.get(view)+'/'+url);
                } else {
                    // otherwise return a path from the root Hudson

core/src/test/java/hudson/FunctionsTest.java

@@ -23,31 +23,30 @@
 */
package hudson;

import static org.junit.Assert.assertEquals;
import static org.powermock.api.mockito.PowerMockito.mock;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.when;
import hudson.model.Action;
import hudson.model.Computer;
import hudson.model.Item;
import hudson.model.ItemGroup;
import hudson.model.TopLevelItem;
import hudson.model.View;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.logging.Level;
import java.util.logging.LogRecord;

import jenkins.model.Jenkins;

import static org.junit.Assert.assertEquals;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.jvnet.hudson.test.Bug;
import org.kohsuke.stapler.Ancestor;
import org.kohsuke.stapler.Stapler;
import org.kohsuke.stapler.StaplerRequest;
import static org.powermock.api.mockito.PowerMockito.mock;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.when;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@@ -135,6 +134,23 @@ public void testGetRelativeLinkTo_JobContainedInView() throws Exception{
        assertEquals("job/i/", result);
    }

    @Test
    @PrepareForTest({Stapler.class, Jenkins.class})
    public void testGetRelativeLinkTo_JobFromComputer() throws Exception{
        Jenkins j = createMockJenkins();
        ItemGroup parent = j;
        String contextPath = "/jenkins";
        StaplerRequest req = createMockRequest(contextPath);
        mockStatic(Stapler.class);
        when(Stapler.getCurrentRequest()).thenReturn(req);
        Computer computer = mock(Computer.class);
        createMockAncestors(req, createAncestor(computer, "."), createAncestor(j, "../.."));
        TopLevelItem i = createMockItem(parent, "job/i/");
        String result = Functions.getRelativeLinkTo(i);
        assertEquals("/jenkins/job/i/", result);
    }

    @Ignore("too expensive to make it correct")
    @Test
    @PrepareForTest({Stapler.class, Jenkins.class})
    public void testGetRelativeLinkTo_JobNotContainedInView() throws Exception{