Add plugin ordering annotations and implementation

core/src/main/java/org/teavm/vm/TeaVMPluginLoader.java

@@ -0,0 +1,266 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed 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.teavm.vm;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import org.objectweb.asm.AnnotationVisitor;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.Type;
+import org.teavm.vm.spi.After;
+import org.teavm.vm.spi.Before;
+import org.teavm.vm.spi.Requires;
+import org.teavm.vm.spi.TeaVMPlugin;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public final class TeaVMPluginLoader {
+    private static final String DESCRIPTOR_LOCATION = "META-INF/services/org.teavm.vm.spi.TeaVMPlugin";
+    private static final String REQUIRES_DESC = Type.getDescriptor(Requires.class);
+    private static final String BEFORE_DESC = Type.getDescriptor(Before.class);
+    private static final String AFTER_DESC = Type.getDescriptor(After.class);
+
+    private TeaVMPluginLoader() {
+    }
+
+    public static List<TeaVMPlugin> load(ClassLoader classLoader) {
+        Set<String> unorderedPlugins = new HashSet<>();
+        try {
+            Enumeration<URL> resourceFiles = classLoader.getResources(DESCRIPTOR_LOCATION);
+            while (resourceFiles.hasMoreElements()) {
+                URL resourceFile = resourceFiles.nextElement();
+                try (BufferedReader input = new BufferedReader(
+                        new InputStreamReader(resourceFile.openStream(), "UTF-8"))) {
+                    readPlugins(input, unorderedPlugins);
+                }
+            }
+        } catch (IOException e) {
+            throw new IllegalStateException("Error loading plugins", e);
+        }
+
+        return orderPlugins(classLoader, unorderedPlugins).stream().map(p -> instantiate(classLoader, p))
+                .collect(Collectors.toList());
+    }
+
+    public static List<String> orderPlugins(ClassLoader classLoader, Set<String> classNames) {
+        Map<String, PluginDescriptor> descriptors = new HashMap<>();
+        try {
+            for (String className : classNames) {
+                PluginDescriptor descriptor = new PluginDescriptor();
+                descriptor.name = className;
+                if (readDescriptor(classLoader, className, descriptor)) {
+                    descriptors.put(className, descriptor);
+                }
+            }
+        } catch (IOException e) {
+            throw new IllegalStateException("Error ordering plugins", e);
+        }
+
+        findReachableDescriptors(descriptors);
+        processDescriptors(descriptors);
+        List<String> plugins = new ArrayList<>();
+        Set<String> visited = new HashSet<>();
+        Set<String> emmited = new HashSet<>();
+        for (PluginDescriptor descriptor : descriptors.values()) {
+            orderDescriptors(descriptor, descriptors, plugins, visited, emmited, new ArrayList<>());
+        }
+
+        return plugins;
+    }
+
+    private static void readPlugins(BufferedReader input, Set<String> plugins) throws IOException {
+        while (true) {
+            String line = input.readLine();
+            if (line == null) {
+                break;
+            }
+            line = line.trim();
+            if (line.isEmpty() || line.startsWith("#")) {
+                continue;
+            }
+
+            plugins.add(line);
+        }
+    }
+
+    private static boolean readDescriptor(ClassLoader classLoader, String className, PluginDescriptor descriptor)
+            throws IOException {
+        try (InputStream input = classLoader.getResourceAsStream(className.replace('.', '/') + ".class")) {
+            if (input == null) {
+                return false;
+            }
+            ClassReader reader = new ClassReader(input);
+            PluginDescriptorFiller filler = new PluginDescriptorFiller(descriptor);
+            reader.accept(filler, 0);
+            return true;
+        }
+    }
+
+    private static void findReachableDescriptors(Map<String, PluginDescriptor> descriptors) {
+        Set<String> visited = new HashSet<>();
+        for (String plugin : descriptors.keySet()) {
+            isReachable(plugin, visited, descriptors);
+        }
+    }
+
+    private static boolean isReachable(String plugin, Set<String> visited, Map<String, PluginDescriptor> descriptors) {
+        PluginDescriptor descriptor = descriptors.get(plugin);
+        if (descriptor == null) {
+            return false;
+        }
+        if (!visited.add(plugin)) {
+            return descriptor.reachable;
+        }
+
+        boolean reachable = true;
+        for (String required : descriptor.requires) {
+            if (!isReachable(required, visited, descriptors)) {
+                reachable = false;
+                break;
+            }
+        }
+        descriptor.reachable = reachable;
+        return reachable;
+    }
+
+    private static void processDescriptors(Map<String, PluginDescriptor> descriptors) {
+        for (PluginDescriptor descriptor : descriptors.values()) {
+            if (descriptor.after.length > 0 && descriptor.before.length > 0) {
+                throw new IllegalStateException("Plugin " + descriptor.name
+                        + " has both before and after annotations");
+            }
+            descriptor.beforeList.addAll(Arrays.asList(descriptor.before));
+            for (String after : descriptor.after) {
+                PluginDescriptor afterDescriptor = descriptors.get(after);
+                if (afterDescriptor != null && afterDescriptor.reachable) {
+                    afterDescriptor.beforeList.add(descriptor.name);
+                }
+            }
+        }
+    }
+
+    private static void orderDescriptors(PluginDescriptor descriptor, Map<String, PluginDescriptor> descriptors,
+            List<String> list, Set<String> visited, Set<String> emmited, List<String> path) {
+        if (!descriptor.reachable) {
+            return;
+        }
+        if (!visited.add(descriptor.name)) {
+            return;
+        }
+        path.add(descriptor.name);
+
+        for (String before : descriptor.beforeList) {
+            PluginDescriptor beforeDescriptor = descriptors.get(before);
+            if (beforeDescriptor != null) {
+                if (visited.contains(before) && !emmited.contains(before)) {
+                    List<String> loop = new ArrayList<>();
+                    for (String pathElem : path) {
+                        loop.add(pathElem);
+                        if (pathElem.equals(descriptor.name)) {
+                            break;
+                        }
+                    }
+                    Collections.reverse(loop);
+                    throw new IllegalStateException("Circular dependency found: " + loop.stream()
+                            .collect(Collectors.joining(" -> ")));
+                }
+                orderDescriptors(beforeDescriptor, descriptors, list, visited, emmited, path);
+            }
+        }
+
+        emmited.add(descriptor.name);
+        path.remove(descriptor.name);
+        list.add(descriptor.name);
+    }
+
+    private static TeaVMPlugin instantiate(ClassLoader classLoader, String className) {
+        try {
+            return (TeaVMPlugin) Class.forName(className, true, classLoader).newInstance();
+        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
+            throw new IllegalStateException("Can't instantiate plugin " + className, e);
+        }
+    }
+
+    static class PluginDescriptorFiller extends ClassVisitor {
+        PluginDescriptor descriptor;
+
+        public PluginDescriptorFiller(PluginDescriptor descriptor) {
+            super(Opcodes.ASM5);
+            this.descriptor = descriptor;
+        }
+
+        @Override
+        public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
+            if (desc.equals(REQUIRES_DESC)) {
+                return readClassArray(arr -> descriptor.requires = arr);
+            } else if (desc.equals(BEFORE_DESC)) {
+                return readClassArray(arr -> descriptor.before = arr);
+            } else if (desc.equals(AFTER_DESC)) {
+                return readClassArray(arr -> descriptor.after = arr);
+            }
+            return null;
+        }
+
+        private AnnotationVisitor readClassArray(Consumer<String[]> resultConsumer) {
+            return new AnnotationVisitor(Opcodes.ASM5) {
+                @Override
+                public AnnotationVisitor visitArray(String name) {
+                    List<String> values = new ArrayList<>();
+                    if (name.equals("value")) {
+                        return new AnnotationVisitor(Opcodes.ASM5) {
+                            @Override
+                            public void visit(String name, Object value) {
+                                values.add(((Type) value).getClassName());
+                            }
+                            @Override
+                            public void visitEnd() {
+                                resultConsumer.accept(values.toArray(new String[0]));
+                            }
+                        };
+                    }
+                    return null;
+                }
+            };
+        }
+    }
+
+    static class PluginDescriptor {
+        String name;
+        String[] requires = new String[0];
+        String[] before = new String[0];
+        String[] after = new String[0];
+        List<String> beforeList = new ArrayList<>();
+        boolean reachable;
+    }
+}

core/src/main/java/org/teavm/vm/spi/After.java

@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed 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.teavm.vm.spi;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+public @interface After {
+    Class<? extends TeaVMPlugin>[] value();
+}

core/src/main/java/org/teavm/vm/spi/Before.java

@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed 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.teavm.vm.spi;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+public @interface Before {
+    Class<? extends TeaVMPlugin>[] value();
+}

core/src/main/java/org/teavm/vm/spi/Requires.java

@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed 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.teavm.vm.spi;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+public @interface Requires {
+    Class<? extends TeaVMPlugin>[] value();
+}

core/src/test/java/org/teavm/vm/PluginLoaderTest.java

@@ -0,0 +1,60 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed 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.teavm.vm;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.junit.Test;
+import org.teavm.vm.spi.Before;
+import org.teavm.vm.spi.Requires;
+import org.teavm.vm.spi.TeaVMHost;
+import org.teavm.vm.spi.TeaVMPlugin;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public class PluginLoaderTest {
+    @Test
+    public void loadsPlugins() {
+        List<String> plugins = order(A.class, B.class);
+        assertThat(plugins.size(), is(2));
+        assertThat(plugins.get(0), is(B.class.getName()));
+        assertThat(plugins.get(1), is(A.class.getName()));
+    }
+
+    private List<String> order(Class<?>... classes) {
+        return TeaVMPluginLoader.orderPlugins(PluginLoaderTest.class.getClassLoader(),
+                Arrays.stream(classes).map(Class::getName).collect(Collectors.toSet()));
+    }
+
+    static class A implements TeaVMPlugin {
+        @Override
+        public void install(TeaVMHost host) {
+        }
+    }
+
+    @Before(A.class)
+    @Requires(A.class)
+    static class B implements TeaVMPlugin {
+        @Override
+        public void install(TeaVMHost host) {
+        }
+    }
+}