Implement DI scopes

... and reuse them for Sisu

Author: gnodet

maven-api-impl/pom.xml

@@ -71,6 +71,10 @@ under the License.
       <groupId>org.apache.maven</groupId>
       <artifactId>maven-api-settings</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.maven</groupId>
+      <artifactId>maven-di</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.apache.maven.resolver</groupId>
       <artifactId>maven-resolver-api</artifactId>
@@ -132,11 +136,6 @@ under the License.
       <groupId>org.assertj</groupId>
       <artifactId>assertj-core</artifactId>
     </dependency>
-    <dependency>
-      <groupId>org.apache.maven</groupId>
-      <artifactId>maven-di</artifactId>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>org.apache.maven.resolver</groupId>
       <artifactId>maven-resolver-named-locks</artifactId>

maven-api-impl/src/main/java/org/apache/maven/internal/impl/di/MojoExecutionScope.java

@@ -0,0 +1,124 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.internal.impl.di;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.function.Supplier;
+
+import org.apache.maven.api.annotations.Nonnull;
+import org.apache.maven.di.Key;
+import org.apache.maven.di.Scope;
+import org.apache.maven.di.impl.DIException;
+
+/**
+ * MojoExecutionScope
+ */
+public class MojoExecutionScope implements Scope {
+
+    protected static final class ScopeState {
+        private final Map<Key<?>, Supplier<?>> seeded = new HashMap<>();
+
+        private final Map<Key<?>, Object> provided = new HashMap<>();
+
+        public <T> void seed(Class<T> clazz, Supplier<T> value) {
+            seeded.put(Key.of(clazz), value);
+        }
+
+        public Collection<Object> provided() {
+            return provided.values();
+        }
+    }
+
+    private final ThreadLocal<LinkedList<ScopeState>> values = new ThreadLocal<>();
+
+    public MojoExecutionScope() {}
+
+    public static <T> Supplier<T> seededKeySupplier(Class<? extends T> clazz) {
+        return () -> {
+            throw new IllegalStateException(
+                    "No instance of " + clazz.getName() + " is bound to the mojo execution scope.");
+        };
+    }
+
+    public void enter() {
+        LinkedList<ScopeState> stack = values.get();
+        if (stack == null) {
+            stack = new LinkedList<>();
+            values.set(stack);
+        }
+        stack.addFirst(new ScopeState());
+    }
+
+    protected ScopeState getScopeState() {
+        LinkedList<ScopeState> stack = values.get();
+        if (stack == null || stack.isEmpty()) {
+            throw new IllegalStateException();
+        }
+        return stack.getFirst();
+    }
+
+    public void exit() {
+        final LinkedList<ScopeState> stack = values.get();
+        if (stack == null || stack.isEmpty()) {
+            throw new IllegalStateException();
+        }
+        stack.removeFirst();
+        if (stack.isEmpty()) {
+            values.remove();
+        }
+    }
+
+    public <T> void seed(Class<T> clazz, Supplier<T> value) {
+        getScopeState().seed(clazz, value);
+    }
+
+    public <T> void seed(Class<T> clazz, final T value) {
+        seed(clazz, (Supplier<T>) () -> value);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Nonnull
+    public <T> Supplier<T> scope(@Nonnull Key<T> key, @Nonnull Supplier<T> unscoped) {
+        return () -> {
+            LinkedList<ScopeState> stack = values.get();
+            if (stack == null || stack.isEmpty()) {
+                throw new DIException("Cannot access " + key + " outside of a scoping block");
+            }
+
+            ScopeState state = stack.getFirst();
+
+            Supplier<?> seeded = state.seeded.get(key);
+
+            if (seeded != null) {
+                return (T) seeded.get();
+            }
+
+            T provided = (T) state.provided.get(key);
+            if (provided == null && unscoped != null) {
+                provided = unscoped.get();
+                state.provided.put(key, provided);
+            }
+
+            return provided;
+        };
+    }
+}

maven-api-impl/src/main/java/org/apache/maven/internal/impl/di/OutOfScopeException.java

@@ -0,0 +1,31 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.internal.impl.di;
+
+import org.apache.maven.di.impl.DIException;
+
+public class OutOfScopeException extends DIException {
+    public OutOfScopeException(String message) {
+        super(message);
+    }
+
+    public OutOfScopeException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

maven-api-impl/src/main/java/org/apache/maven/internal/impl/di/SessionScope.java

@@ -0,0 +1,183 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.internal.impl.di;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+import org.apache.maven.di.Key;
+import org.apache.maven.di.Scope;
+import org.apache.maven.di.impl.Types;
+
+public class SessionScope implements Scope {
+
+    /**
+     * ScopeState
+     */
+    protected static final class ScopeState {
+        private final Map<Key<?>, CachingProvider<?>> provided = new ConcurrentHashMap<>();
+
+        public <T> void seed(Class<T> clazz, Supplier<T> value) {
+            provided.put(Key.of(clazz), new CachingProvider<>(value));
+        }
+
+        @SuppressWarnings("unchecked")
+        public <T> Supplier<T> scope(Key<T> key, Supplier<T> unscoped) {
+            Supplier<?> provider = provided.computeIfAbsent(key, k -> new CachingProvider<>(unscoped));
+            return (Supplier<T>) provider;
+        }
+
+        public Collection<CachingProvider<?>> providers() {
+            return provided.values();
+        }
+    }
+
+    protected final List<ScopeState> values = new CopyOnWriteArrayList<>();
+
+    public void enter() {
+        values.add(0, new ScopeState());
+    }
+
+    protected ScopeState getScopeState() {
+        if (values.isEmpty()) {
+            throw new OutOfScopeException("Cannot access session scope outside of a scoping block");
+        }
+        return values.get(0);
+    }
+
+    public void exit() {
+        if (values.isEmpty()) {
+            throw new IllegalStateException();
+        }
+        values.remove(0);
+    }
+
+    public <T> void seed(Class<T> clazz, Supplier<T> value) {
+        getScopeState().seed(clazz, value);
+    }
+
+    public <T> void seed(Class<T> clazz, T value) {
+        seed(clazz, (Supplier<T>) () -> value);
+    }
+
+    @Override
+    public <T> Supplier<T> scope(Key<T> key, Supplier<T> unscoped) {
+        // Lazy evaluating provider
+        return () -> {
+            if (values.isEmpty()) {
+                return createProxy(key, unscoped);
+            } else {
+                return getScopeState().scope(key, unscoped).get();
+            }
+        };
+    }
+
+    @SuppressWarnings("unchecked")
+    protected <T> T createProxy(Key<T> key, Supplier<T> unscoped) {
+        InvocationHandler dispatcher = (proxy, method, args) -> {
+            method.setAccessible(true);
+            try {
+                return method.invoke(getScopeState().scope(key, unscoped).get(), args);
+            } catch (InvocationTargetException e) {
+                throw e.getCause();
+            }
+        };
+        Class<T> superType = (Class<T>) Types.getRawType(key.getType());
+        Class<?>[] interfaces = getInterfaces(superType);
+        return (T) java.lang.reflect.Proxy.newProxyInstance(superType.getClassLoader(), interfaces, dispatcher);
+    }
+
+    protected Class<?>[] getInterfaces(Class<?> superType) {
+        if (superType.isInterface()) {
+            return new Class<?>[] {superType};
+        } else {
+            for (Annotation a : superType.getAnnotations()) {
+                Class<? extends Annotation> annotationType = a.annotationType();
+                if (isTypeAnnotation(annotationType)) {
+                    try {
+                        Class<?>[] value =
+                                (Class<?>[]) annotationType.getMethod("value").invoke(a);
+                        if (value.length == 0) {
+                            value = superType.getInterfaces();
+                        }
+                        List<Class<?>> nonInterfaces =
+                                Stream.of(value).filter(c -> !c.isInterface()).toList();
+                        if (!nonInterfaces.isEmpty()) {
+                            throw new IllegalArgumentException(
+                                    "The Typed annotation must contain only interfaces but the following types are not: "
+                                            + nonInterfaces);
+                        }
+                        return value;
+                    } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
+                        throw new IllegalStateException(e);
+                    }
+                }
+            }
+            throw new IllegalArgumentException("The use of session scoped proxies require "
+                    + "a org.eclipse.sisu.Typed or javax.enterprise.inject.Typed annotation");
+        }
+    }
+
+    protected boolean isTypeAnnotation(Class<? extends Annotation> annotationType) {
+        return "org.apache.maven.api.di.Typed".equals(annotationType.getName());
+    }
+
+    /**
+     * A provider wrapping an existing provider with a cache
+     * @param <T> the provided type
+     */
+    protected static class CachingProvider<T> implements Supplier<T> {
+        private final Supplier<T> provider;
+        private volatile T value;
+
+        CachingProvider(Supplier<T> provider) {
+            this.provider = provider;
+        }
+
+        public T value() {
+            return value;
+        }
+
+        @Override
+        public T get() {
+            if (value == null) {
+                synchronized (this) {
+                    if (value == null) {
+                        value = provider.get();
+                    }
+                }
+            }
+            return value;
+        }
+    }
+
+    public static <T> Supplier<T> seededKeySupplier(Class<? extends T> clazz) {
+        return () -> {
+            throw new IllegalStateException("No instance of " + clazz.getName() + " is bound to the session scope.");
+        };
+    }
+}