-
Notifications
You must be signed in to change notification settings - Fork 65
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Implement OSGi Service Loader Mediator Specification
Signed-off-by: Hannes Wellmann <[email protected]>
- Loading branch information
1 parent
3bd3dbd
commit a9391e4
Showing
3 changed files
with
174 additions
and
1 deletion.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
169 changes: 169 additions & 0 deletions
169
...eclipse.osgi/container/src/org/eclipse/osgi/internal/hooks/ServiceLoaderMediatorHook.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,169 @@ | ||
| package org.eclipse.osgi.internal.hooks; | ||
|
|
||
| import java.io.FileNotFoundException; | ||
| import java.io.IOException; | ||
| import java.lang.reflect.Method; | ||
| import java.net.URL; | ||
| import java.util.Arrays; | ||
| import java.util.Collections; | ||
| import java.util.Enumeration; | ||
| import java.util.HashSet; | ||
| import java.util.List; | ||
| import java.util.Objects; | ||
| import java.util.Optional; | ||
| import java.util.ServiceLoader; | ||
| import java.util.Set; | ||
| import java.util.function.Function; | ||
| import java.util.function.Supplier; | ||
| import java.util.stream.Collectors; | ||
| import java.util.stream.IntStream; | ||
| import java.util.stream.Stream; | ||
| import org.eclipse.osgi.internal.hookregistry.ClassLoaderHook; | ||
| import org.eclipse.osgi.internal.loader.ModuleClassLoader; | ||
| import org.osgi.framework.Constants; | ||
| import org.osgi.framework.wiring.BundleRequirement; | ||
| import org.osgi.framework.wiring.BundleWire; | ||
| import org.osgi.framework.wiring.BundleWiring; | ||
|
|
||
| public class ServiceLoaderMediatorHook extends ClassLoaderHook { | ||
|
|
||
| @SuppressWarnings({ "unchecked", "rawtypes" }) | ||
| private Supplier<Optional<Class<?>>> getCallerClassComputer() { | ||
| try { // The Java-9+ way | ||
| Class<?> stackWalkerClass = Class.forName("java.lang.StackWalker"); //$NON-NLS-1$ | ||
| Class stackWalkerOption = Class.forName("java.lang.StackWalker$Option"); //$NON-NLS-1$ | ||
| Enum<?> retainClassReference = Enum.valueOf(stackWalkerOption, "RETAIN_CLASS_REFERENCE"); //$NON-NLS-1$ | ||
| Object stackWalker = stackWalkerClass.getMethod("getInstance", Set.class, int.class).invoke(null, //$NON-NLS-1$ | ||
| new HashSet<>(Arrays.asList(retainClassReference)), 15); | ||
|
|
||
| Method stackWalkerWalk = stackWalkerClass.getMethod("walk", Function.class); //$NON-NLS-1$ | ||
| Class<?> stackFrameClass = Class.forName("java.lang.StackWalker$StackFrame"); //$NON-NLS-1$ | ||
| Method stackFrameGetDeclaringClass = stackFrameClass.getMethod("getDeclaringClass"); //$NON-NLS-1$ | ||
|
|
||
| Function<Stream<?>, Optional<Class<?>>> function = frames -> frames.<Class<?>>map(f -> { | ||
| try { | ||
| return (Class<?>) stackFrameGetDeclaringClass.invoke(f); | ||
| } catch (ReflectiveOperationException e) { | ||
| return null; | ||
| } | ||
| }).filter(Objects::nonNull).limit(15) | ||
| .filter(c -> c == ServiceLoader.class || c.getEnclosingClass() == ServiceLoader.class).findFirst(); | ||
|
|
||
| return () -> { | ||
| try { | ||
| return (Optional<Class<?>>) stackWalkerWalk.invoke(stackWalker, function); | ||
| } catch (ReflectiveOperationException e) { | ||
| return Optional.empty(); | ||
| } | ||
| }; | ||
| } catch (ReflectiveOperationException e) { // ignore | ||
| } | ||
| try { // Try the Java-1.8 way | ||
| Class<?> reflectionClass = Class.forName("sun.reflect.Reflection"); //$NON-NLS-1$ | ||
| Method getCallerClass = Objects.requireNonNull(reflectionClass.getMethod("getCallerClass", int.class)); //$NON-NLS-1$ | ||
| return () -> IntStream.range(0, 15).<Class<?>>mapToObj(i -> { | ||
| try { | ||
| return (Class<?>) getCallerClass.invoke(null, i); | ||
| } catch (ReflectiveOperationException e) { | ||
| return null; | ||
| } | ||
| }).filter(Objects::nonNull) | ||
| .filter(c -> c == ServiceLoader.class || c.getEnclosingClass() == ServiceLoader.class).findFirst(); | ||
|
|
||
| } catch (ReflectiveOperationException e) { // ignore an try Java-8 way | ||
| } | ||
| throw new AssertionError("Neither the Java-8 nor the Java-9+ way to obtain the caller class is available"); //$NON-NLS-1$ | ||
| } | ||
|
|
||
| private static final String SERVICE_NAME_PREFIX = "META-INF/services/"; //$NON-NLS-1$ | ||
|
|
||
| private final ThreadLocal<String> latestServiceName = new ThreadLocal<>(); | ||
|
|
||
| private final Supplier<Optional<Class<?>>> callerClass = getCallerClassComputer(); | ||
|
|
||
| @Override | ||
| public Enumeration<URL> preFindResources(String name, ModuleClassLoader classLoader) throws FileNotFoundException { | ||
| if (name.startsWith(SERVICE_NAME_PREFIX)) { | ||
| Stream<URL> serviceProviderFiles = searchProviders(name, classLoader, cl -> { | ||
| try { | ||
| Enumeration<URL> resources = cl.getResources(name); | ||
| return Collections.list(resources).stream(); | ||
| } catch (IOException e) { | ||
| return Stream.empty(); | ||
| } | ||
| }); | ||
| if (serviceProviderFiles != null) { | ||
| latestServiceName.set(name); | ||
| List<URL> services = serviceProviderFiles.collect(Collectors.toList()); | ||
| return Collections.enumeration(services); | ||
| } | ||
| } | ||
| return null; | ||
| } | ||
|
|
||
| @Override | ||
| public Class<?> preFindClass(String name, ModuleClassLoader classLoader) throws ClassNotFoundException { | ||
| String serviceName = latestServiceName.get(); // This cannot be removed if subsequent class load other | ||
| // providers for the same service | ||
| if (serviceName != null) { | ||
| Stream<Class<?>> services = searchProviders(serviceName, classLoader, cl -> { | ||
| try { | ||
| return Stream.of(cl.loadClass(name)); | ||
| } catch (ClassNotFoundException | NoClassDefFoundError e) { // ignore | ||
| return Stream.empty(); | ||
| } | ||
| }); | ||
| if (services != null) { | ||
| Optional<Class<?>> findFirst = services.findFirst(); | ||
| return findFirst.orElse(null); | ||
| } | ||
| } | ||
| return null; | ||
| } | ||
|
|
||
| private <T> Stream<T> searchProviders(String name, ModuleClassLoader classLoader, | ||
| Function<ClassLoader, Stream<T>> mapper) { | ||
| BundleWiring wiring = classLoader.getBundle().adapt(BundleWiring.class); | ||
| if (requiresServiceLoaderProcessor(wiring) && isCalledFromServiceLoader()) { | ||
| return Stream.concat(Stream.of(classLoader), providerClassLoaders(name, wiring)).flatMap(mapper); | ||
| } | ||
| return null; | ||
| } | ||
|
|
||
| private boolean requiresServiceLoaderProcessor(BundleWiring wiring) { | ||
| List<BundleWire> requiredWires = wiring.getRequiredWires("osgi.extender"); //$NON-NLS-1$ | ||
| if (requiredWires.isEmpty()) { | ||
| return false; | ||
| } | ||
| return requiredWires.stream().anyMatch(w -> w.getRequirement().getDirectives().getOrDefault("filter", "") //$NON-NLS-1$//$NON-NLS-2$ | ||
| .contains("(osgi.extender=osgi.serviceloader.processor)") //$NON-NLS-1$ | ||
| && w.getProvider().getBundle().getBundleId() == Constants.SYSTEM_BUNDLE_ID); | ||
| } | ||
|
|
||
| private boolean isCalledFromServiceLoader() { | ||
| Optional<Class<?>> caller = callerClass.get(); | ||
| // TODO: If Java-9+ is required one day, just use the following code | ||
| // ClassLoader thisLoader = ServiceLoaderMediatorHook.class.getClassLoader(); | ||
| // Optional<Class<?>> caller = WALKER.walk(frames -> frames.<Class<?>>map(f -> f.getDeclaringClass()) | ||
| // .dropWhile(c -> c.getName().startsWith("org.eclipse.osgi") && c.getClassLoader() == thisLoader) //$NON-NLS-1$ | ||
| // .findFirst()); | ||
| return caller.isPresent() && caller.get().getEnclosingClass() == ServiceLoader.class; | ||
| } | ||
|
|
||
| private static Stream<ClassLoader> providerClassLoaders(String name, BundleWiring wiring) { | ||
| List<BundleWire> requiredWires = wiring.getRequiredWires("osgi.serviceloader"); //$NON-NLS-1$ | ||
| if (!requiredWires.isEmpty()) { | ||
| String serviceName = name.substring(SERVICE_NAME_PREFIX.length()); | ||
| return requiredWires.stream().filter(wire -> { | ||
| BundleRequirement requirement = wire.getRequirement(); | ||
| String filterDirective = requirement.getDirectives().get("filter"); //$NON-NLS-1$ | ||
| Object serviceLoaderAttribute = wire.getCapability().getAttributes().get("osgi.serviceloader"); //$NON-NLS-1$ | ||
| return serviceName.equals(serviceLoaderAttribute) | ||
| && ("(osgi.serviceloader=" + serviceName + ")").equals(filterDirective); //$NON-NLS-1$ //$NON-NLS-2$ | ||
| }).map(wire -> wire.getProviderWiring().getClassLoader()); | ||
|
|
||
| } | ||
| return Stream.empty(); | ||
| } | ||
|
|
||
| } |