[GR-44291] Automatically register resources when the class and the pattern are constant.

docs/reference-manual/native-image/ReachabilityMetadata.md

@@ -221,7 +221,15 @@ Java is capable of accessing any resource on the application class path, or the
 Resource metadata instructs the `native-image` builder to include specified resources and resource bundles in the produced binary.
 A consequence of this approach is that some parts of the application that use resources for configuration (such as logging) are effectively configured at build time.
 
-The code below accesses a text file and requires providing resource metadata: 
+### Resource Metadata In Code
+Native Image will detect calls to `java.lang.Class#getResource` and `java.lang.Class#getResourceAsStream` in which:
+ - The class on which these methods are called is constant
+ - The first parameter, `name`, is a constant
+and automatically register such resources.
+
+The code below will work out of the box, because:
+ - We are using a class literal (`Example.class`)
+ - We are using a string literal as the `name` parameter
 ```java
 class Example {
     public void conquerTheWorld() {
@@ -232,9 +240,6 @@ class Example {
 }
 ```
 
-### Resource Metadata In Code
-It is not possible to specify used resources and resource bundles in code.
-
 ### Resource Metadata in JSON
 Metadata for resources is provided in `resource-config.json` files.
 ```json
@@ -401,4 +406,4 @@ The JSON schema is accompanied by the `agent-extracted-predefined-classes` direc
 
 * [Metadata Collection with the Tracing Agent](AutomaticMetadataCollection.md)
 * [Native Image Compatibility Guide](Compatibility.md)
-* [GraalVM Reachability Metadata Repository](https://github.com/oracle/graalvm-reachability-metadata)
+* [GraalVM Reachability Metadata Repository](https://github.com/oracle/graalvm-reachability-metadata)

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/ResourcesFeature.java

@@ -28,11 +28,17 @@
 import static com.oracle.svm.core.jdk.Resources.RESOURCES_INTERNAL_PATH_SEPARATOR;
 
 import java.io.InputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 import java.net.URI;
 import java.nio.file.FileSystem;
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -43,15 +49,24 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import org.graalvm.compiler.api.replacements.SnippetReflectionProvider;
 import org.graalvm.compiler.debug.DebugContext;
+import org.graalvm.compiler.nodes.ValueNode;
+import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;
+import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderContext;
+import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugin;
+import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugins;
 import org.graalvm.compiler.options.Option;
 import org.graalvm.compiler.options.OptionType;
+import org.graalvm.compiler.phases.util.Providers;
 import org.graalvm.nativeimage.ImageSingletons;
+import org.graalvm.nativeimage.hosted.RuntimeResourceAccess;
 import org.graalvm.nativeimage.impl.ConfigurationCondition;
 import org.graalvm.nativeimage.impl.RuntimeResourceSupport;
 
 import com.oracle.svm.core.ClassLoaderSupport;
 import com.oracle.svm.core.ClassLoaderSupport.ResourceCollector;
+import com.oracle.svm.core.ParsingReason;
 import com.oracle.svm.core.SubstrateUtil;
 import com.oracle.svm.core.configure.ConfigurationFile;
 import com.oracle.svm.core.configure.ConfigurationFiles;
@@ -67,9 +82,13 @@
 import com.oracle.svm.core.option.HostedOptionKey;
 import com.oracle.svm.core.option.LocatableMultiOptionValue;
 import com.oracle.svm.core.util.UserError;
+import com.oracle.svm.core.util.VMError;
 import com.oracle.svm.hosted.FeatureImpl.DuringAnalysisAccessImpl;
 import com.oracle.svm.hosted.config.ConfigurationParserUtils;
 import com.oracle.svm.hosted.jdk.localization.LocalizationFeature;
+import com.oracle.svm.util.ReflectionUtil;
+
+import jdk.vm.ci.meta.ResolvedJavaMethod;
 
 /**
  * <p>
@@ -406,4 +425,41 @@ private static void registerDirectoryResource(DebugContext debugContext, String
             Resources.registerDirectoryResource(moduleName, dir, content, fromJar);
         }
     }
+
+    @Override
+    public void registerInvocationPlugins(Providers providers, SnippetReflectionProvider snippetReflection, GraphBuilderConfiguration.Plugins plugins, ParsingReason reason) {
+        Method[] resourceMethods = {
+                        ReflectionUtil.lookupMethod(Class.class, "getResource", String.class),
+                        ReflectionUtil.lookupMethod(Class.class, "getResourceAsStream", String.class)
+        };
+        Method resolveResourceName = ReflectionUtil.lookupMethod(Class.class, "resolveName", String.class);
+
+        for (Method method : resourceMethods) {
+            registerResourceRegistrationPlugin(plugins.getInvocationPlugins(), method, snippetReflection, resolveResourceName);
+        }
+    }
+
+    private void registerResourceRegistrationPlugin(InvocationPlugins plugins, Method method, SnippetReflectionProvider snippetReflectionProvider, Method resolveResourceName) {
+        List<Class<?>> parameterTypes = new ArrayList<>();
+        assert !Modifier.isStatic(method.getModifiers());
+        parameterTypes.add(InvocationPlugin.Receiver.class);
+        parameterTypes.addAll(Arrays.asList(method.getParameterTypes()));
+
+        plugins.register(method.getDeclaringClass(), new InvocationPlugin.RequiredInvocationPlugin(method.getName(), parameterTypes.toArray(new Class<?>[0])) {
+            @Override
+            public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver receiver, ValueNode arg) {
+                try {
+                    if (!sealed && receiver.isConstant() && arg.isJavaConstant() && !arg.isNullConstant()) {
+                        String resource = snippetReflectionProvider.asObject(String.class, arg.asJavaConstant());
+                        Class<?> clazz = snippetReflectionProvider.asObject(Class.class, receiver.get().asJavaConstant());
+                        String resourceName = (String) resolveResourceName.invoke(clazz, resource);
+                        RuntimeResourceAccess.addResource(clazz.getModule(), resourceName);
+                    }
+                } catch (IllegalAccessException | InvocationTargetException e) {
+                    throw VMError.shouldNotReachHere(e);
+                }
+                return false;
+            }
+        });
+    }
 }