Fix static resource handling with GraalVM 21.2

Related to spring-projects/spring-framework#27538

Closes gh-1174

samples/webmvc-tomcat/src/main/resources/static/foo.html

@@ -0,0 +1 @@
+Foo

samples/webmvc-tomcat/verify.sh

@@ -1,7 +1,12 @@
 #!/usr/bin/env bash
 RESPONSE=`curl -s localhost:8080/`
 if [[ "$RESPONSE" == 'Hello from Spring MVC and Tomcat' ]]; then
-  exit 0
+  RESPONSE=`curl -s localhost:8080/foo.html`
+  if [[ "$RESPONSE" == 'Foo' ]]; then
+    exit 0
+  else
+    exit 1
+  fi
 else
   exit 1
 fi

spring-native/src/main/java/org/springframework/nativex/substitutions/framework/Target_ApplicationObjectSupport.java

@@ -0,0 +1,17 @@
+package org.springframework.nativex.substitutions.framework;
+
+import com.oracle.svm.core.annotate.Alias;
+import com.oracle.svm.core.annotate.TargetClass;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.nativex.substitutions.OnlyIfPresent;
+
+@TargetClass(className = "org.springframework.context.support.ApplicationObjectSupport", onlyWith = OnlyIfPresent.class)
+final class Target_ApplicationObjectSupport {
+
+	@Alias
+	protected ApplicationContext obtainApplicationContext() {
+		return null;
+	}
+
+}

spring-native/src/main/java/org/springframework/nativex/substitutions/framework/Target_ResourceHttpRequestHandler.java

@@ -0,0 +1,85 @@
+package org.springframework.nativex.substitutions.framework;
+
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import com.oracle.svm.core.annotate.Alias;
+import com.oracle.svm.core.annotate.Substitute;
+import com.oracle.svm.core.annotate.TargetClass;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+import org.springframework.nativex.substitutions.OnlyIfPresent;
+import org.springframework.util.StringValueResolver;
+import org.springframework.web.context.support.ServletContextResource;
+
+// Workaround for https://github.com/spring-projects-experimental/spring-native/issues/1174 with GraalVM 21.2.0 (works fine with GraalVM 21.3.0)
+@TargetClass(className = "org.springframework.web.servlet.resource.ResourceHttpRequestHandler", onlyWith = OnlyIfPresent.class)
+final class Target_ResourceHttpRequestHandler {
+
+	@Alias
+	private List<String> locationValues;
+
+	@Alias
+	private List<Resource> locationResources;
+
+	@Alias
+	private List<Resource> locationsToUse;
+
+	@Alias
+	private Map<Resource, Charset> locationCharsets;
+
+	@Alias
+	private StringValueResolver embeddedValueResolver;
+
+	@Substitute
+	private void resolveResourceLocations() {
+		List<Resource> result = new ArrayList<>();
+		if (!this.locationValues.isEmpty()) {
+			ApplicationContext applicationContext = ((Target_ApplicationObjectSupport)(Object)this).obtainApplicationContext();
+			for (String location : this.locationValues) {
+				if (this.embeddedValueResolver != null) {
+					String resolvedLocation = this.embeddedValueResolver.resolveStringValue(location);
+					if (resolvedLocation == null) {
+						throw new IllegalArgumentException("Location resolved to null: " + location);
+					}
+					location = resolvedLocation;
+				}
+				Charset charset = null;
+				location = location.trim();
+				if (location.startsWith("[charset=")) {
+					int endIndex = location.indexOf(']', "[charset=".length());
+					if (endIndex == -1) {
+						throw new IllegalArgumentException("Invalid charset syntax in location: " + location);
+					}
+					String value = location.substring("[charset=".length(), endIndex);
+					charset = Charset.forName(value);
+					location = location.substring(endIndex + 1);
+				}
+				Resource resource = applicationContext.getResource(location);
+				if (location.equals("/") && !(resource instanceof ServletContextResource)) {
+					throw new IllegalStateException(
+							"The String-based location \"/\" should be relative to the web application root " +
+									"but resolved to a Resource of type: " + resource.getClass() + ". " +
+									"If this is intentional, please pass it as a pre-configured Resource via setLocations.");
+				}
+				result.add(resource);
+				if (charset != null) {
+					if (!(resource instanceof UrlResource)) {
+						throw new IllegalArgumentException("Unexpected charset for non-UrlResource: " + resource);
+					}
+					this.locationCharsets.put(resource, charset);
+				}
+			}
+		}
+
+		result.addAll(this.locationResources);
+
+		this.locationsToUse.clear();
+		this.locationsToUse.addAll(result);
+	}
+
+}

spring-native/src/main/java/org/springframework/nativex/substitutions/framework/Target_ResourceWebHandler.java

@@ -0,0 +1,49 @@
+package org.springframework.nativex.substitutions.framework;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.oracle.svm.core.annotate.Alias;
+import com.oracle.svm.core.annotate.Substitute;
+import com.oracle.svm.core.annotate.TargetClass;
+
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.nativex.substitutions.OnlyIfPresent;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+
+// Workaround for https://github.com/spring-projects-experimental/spring-native/issues/1174 with GraalVM 21.2.0 (works fine with GraalVM 21.3.0)
+@TargetClass(className = "org.springframework.web.reactive.resource.ResourceWebHandler", onlyWith = OnlyIfPresent.class)
+final class Target_ResourceWebHandler {
+
+	@Alias
+	private List<String> locationValues;
+
+	@Alias
+	private  List<Resource> locationResources;
+
+	@Alias
+	private List<Resource> locationsToUse;
+
+	@Alias
+	private ResourceLoader resourceLoader;
+
+	@Substitute
+	private void resolveResourceLocations() {
+		List<Resource> result = new ArrayList<>(this.locationResources);
+
+		if (!this.locationValues.isEmpty()) {
+			Assert.notNull(this.resourceLoader,
+					"ResourceLoader is required when \"locationValues\" are configured.");
+			Assert.isTrue(CollectionUtils.isEmpty(this.locationResources), "Please set " +
+					"either Resource-based \"locations\" or String-based \"locationValues\", but not both.");
+			for (String location : this.locationValues) {
+				result.add(this.resourceLoader.getResource(location));
+			}
+		}
+
+		this.locationsToUse.clear();
+		this.locationsToUse.addAll(result);
+	}
+}