Issue #10926 - add support for CombinedResource in AttributeNormalizer (

#10927)

* #10926 - skip existence check if only one Normalizer
* fix for AttributeNormalizer

---------

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>
Co-authored-by: gregw <gregw@webtide.com>

jetty-core/jetty-util/src/main/java/org/eclipse/jetty/util/resource/AttributeNormalizer.java

@@ -29,6 +29,7 @@
 import java.util.stream.Stream;
 
 import org.eclipse.jetty.util.StringUtil;
+import org.eclipse.jetty.util.URIUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -195,34 +196,39 @@ public String toString()
         return o2.weight - o1.weight;
     };
 
+    private final Resource baseResource;
     private final List<PathAttribute> paths = new ArrayList<>();
     private final List<URIAttribute> uris = new ArrayList<>();
 
     public AttributeNormalizer(Resource baseResource)
     {
         if (baseResource == null)
             throw new IllegalArgumentException("No base resource!");
-        // Combined resources currently are not supported (see #8921) but such support
-        // could be added. That would require some form of (potentially expensive)
-        // existence check in expand() to figure out which URIAttribute actually
-        // contains the resource.
-        if (Resources.isCombined(baseResource))
-            throw new IllegalArgumentException("Base resource cannot be combined!");
+
+        this.baseResource = baseResource;
 
         addSystemProperty("jetty.base", 9);
         addSystemProperty("jetty.home", 8);
         addSystemProperty("user.home", 7);
         addSystemProperty("user.dir", 6);
 
-        URI warURI = toCanonicalURI(baseResource.getURI());
-        if (!warURI.isAbsolute())
-            throw new IllegalArgumentException("WAR URI is not absolute: " + warURI);
-
-        Path path = baseResource.getPath();
-        if (path != null)
-            paths.add(new PathAttribute("WAR.path", toCanonicalPath(path), 10));
-        uris.add(new URIAttribute("WAR.uri", warURI, 9)); // preferred encoding
-        uris.add(new URIAttribute("WAR", warURI, 8)); // legacy encoding
+        int weight = 9;
+        for (Resource base : baseResource)
+        {
+            URI uri = base.getURI();
+            if (uri == null)
+                continue;
+            URI warURI = toCanonicalURI(uri);
+            if (!warURI.isAbsolute())
+                throw new IllegalArgumentException("WAR URI is not absolute: " + warURI);
+
+            Path path = base.getPath();
+            if (path != null)
+                paths.add(new PathAttribute("WAR.path", toCanonicalPath(path), weight));
+            uris.add(new URIAttribute("WAR.uri", warURI, weight - 1)); // preferred encoding
+            uris.add(new URIAttribute("WAR", warURI, weight - 2)); // legacy encoding
+            weight += 3;
+        }
 
         paths.sort(attrComparator);
         uris.sort(attrComparator);
@@ -401,6 +407,24 @@ private String expand(String prefix, String property, String suffix)
         if (property == null)
             return null;
 
+        switch (property)
+        {
+            case "WAR", "WAR.path" ->
+            {
+                Resource r = baseResource.resolve(suffix);
+                if (r == null)
+                    return prefix + URIUtil.addPaths(baseResource.iterator().next().getPath().toString(), suffix);
+                return prefix + r.getPath();
+            }
+            case "WAR.uri" ->
+            {
+                Resource r = baseResource.resolve(suffix);
+                if (r == null)
+                    return prefix + URIUtil.addPaths(baseResource.iterator().next().getURI().toString(), suffix);
+                return prefix + r.getURI();
+            }
+        }
+
         // Check for URI matches
         for (URIAttribute attr : uris)
         {

jetty-core/jetty-util/src/test/java/org/eclipse/jetty/util/resource/AttributeNormalizerTest.java

@@ -31,11 +31,13 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.is;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -101,6 +103,11 @@ private static Path asTargetPath(String title, String subpath)
         return path;
     }
 
+    private static Resource asTargetResource(String title, String subpath)
+    {
+        return resourceFactory.newResource(asTargetPath(title, subpath));
+    }
+
     private static final Map<String, String> originalEnv = new HashMap<>();
     private static ResourceFactory.Closeable resourceFactory;
 
@@ -308,6 +315,35 @@ public void testNormalizeWarDeepAsURI(final Scenario scenario)
         assertNormalize(scenario, testWarDeep.toUri(), "${WAR.uri}/deep/ref");
     }
 
+    @Test
+    public void testCombinedResource() throws Exception
+    {
+        String title = "CombinedResource Setup";
+        Resource r1 = asTargetResource(title, "dir1");
+        Resource r2 = asTargetResource(title, "dir2");
+        Resource r3 = asTargetResource(title, "dir3");
+
+        // Create files in each of these directories.
+        Files.createFile(r1.getPath().resolve("file1")).toFile().deleteOnExit();
+        Files.createFile(r2.getPath().resolve("file2")).toFile().deleteOnExit();
+        Files.createFile(r3.getPath().resolve("file3")).toFile().deleteOnExit();
+
+        Resource combined = CombinedResource.combine(List.of(r1, r2, r3));
+        AttributeNormalizer normalizer = new AttributeNormalizer(combined);
+
+        // Uses the appropriate resource if the target exists.
+        assertThat(normalizer.expand("${WAR.uri}/file1"), containsString("/dir1/file1"));
+        assertThat(normalizer.expand("${WAR.uri}/file2"), containsString("/dir2/file2"));
+        assertThat(normalizer.expand("${WAR.uri}/file3"), containsString("/dir3/file3"));
+        assertThat(normalizer.expand("${WAR.path}/file1"), containsString("/dir1/file1"));
+        assertThat(normalizer.expand("${WAR.path}/file2"), containsString("/dir2/file2"));
+        assertThat(normalizer.expand("${WAR.path}/file3"), containsString("/dir3/file3"));
+
+        // If file cannot be found it just uses the first resource.
+        assertThat(normalizer.expand("${WAR.uri}/file4"), containsString("/dir1/file4"));
+        assertThat(normalizer.expand("${WAR.path}/file4"), containsString("/dir1/file4"));
+    }
+
     public static class Scenario
     {
         private final Path jettyHome;

jetty-ee10/jetty-ee10-quickstart/src/main/java/org/eclipse/jetty/ee10/quickstart/QuickStartDescriptorProcessor.java

@@ -168,7 +168,7 @@ public void visitContextParam(WebAppContext context, Descriptor descriptor, XmlP
                 if (o instanceof Collection<?>)
                     libs.addAll((Collection<?>)o);
                 libs.addAll(values);
-                if (libs.size() > 0)
+                if (!libs.isEmpty())
                     context.setAttribute(ServletContext.ORDERED_LIBS, libs);
             }
             case AnnotationConfiguration.CONTAINER_INITIALIZERS ->