implement option for plugins to use child first classloaders

scm-core/src/main/java/sonia/scm/plugin/Plugin.java

@@ -70,14 +70,17 @@ public final class Plugin extends ScmModule
    * @param information
    * @param resources
    * @param condition
+   * @param childFirstClassLoader
    * @param dependencies
    */
   public Plugin(PluginInformation information, PluginResources resources,
-    PluginCondition condition, Set<String> dependencies)
+    PluginCondition condition, boolean childFirstClassLoader,
+    Set<String> dependencies)
   {
     this.information = information;
     this.resources = resources;
     this.condition = condition;
+    this.childFirstClassLoader = childFirstClassLoader;
     this.dependencies = dependencies;
   }
 
@@ -109,6 +112,7 @@ public final class Plugin extends ScmModule
     return Objects.equal(condition, other.condition)
       && Objects.equal(information, other.information)
       && Objects.equal(resources, other.resources)
+      && Objects.equal(childFirstClassLoader, other.childFirstClassLoader)
       && Objects.equal(dependencies, other.dependencies);
   }
 
@@ -121,7 +125,8 @@ public final class Plugin extends ScmModule
   @Override
   public int hashCode()
   {
-    return Objects.hashCode(condition, information, resources, dependencies);
+    return Objects.hashCode(condition, information, resources,
+      childFirstClassLoader, dependencies);
   }
 
   /**
@@ -138,6 +143,7 @@ public final class Plugin extends ScmModule
                   .add("condition", condition)
                   .add("information", information)
                   .add("resources", resources)
+                  .add("childFirstClassLoader", childFirstClassLoader)
                   .add("dependencies", dependencies)
                   .toString();
     //J+
@@ -196,8 +202,23 @@ public final class Plugin extends ScmModule
     return resources;
   }
 
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  public boolean isChildFirstClassLoader()
+  {
+    return childFirstClassLoader;
+  }
+
   //~--- fields ---------------------------------------------------------------
 
+  /** Field description */
+  @XmlElement(name = "child-first-classloader")
+  private boolean childFirstClassLoader;
+
   /** Field description */
   @XmlElement(name = "conditions")
   private PluginCondition condition;

scm-webapp/src/main/java/sonia/scm/plugin/PluginProcessor.java

@@ -135,77 +135,6 @@ public final class PluginProcessor
 
   //~--- methods --------------------------------------------------------------
 
-  /**
-   * Method description
-   *
-   *
-   * @param parentClassLoader
-   * @param directory
-   *
-   * @return
-   *
-   * @throws IOException
-   */
-  private DefaultPluginClassLoader createClassLoader(
-    ClassLoader parentClassLoader, Path directory)
-    throws IOException
-  {
-    List<URL> urls = new ArrayList<>();
-
-    Path metaDir = directory.resolve(DIRECTORY_METAINF);
-
-    if (!Files.exists(metaDir))
-    {
-      throw new FileNotFoundException("could not find META-INF directory");
-    }
-
-    Path linkDir = directory.resolve(DIRECTORY_LINK);
-
-    if (!Files.exists(linkDir))
-    {
-      Files.createDirectory(linkDir);
-    }
-
-    Path linkMetaDir = linkDir.resolve(DIRECTORY_METAINF);
-
-    if (!Files.exists(linkMetaDir))
-    {
-      Files.deleteIfExists(linkMetaDir);
-      Files.createSymbolicLink(linkMetaDir, linkMetaDir.relativize(metaDir));
-    }
-
-    urls.add(linkDir.toUri().toURL());
-
-    Path webinfDir = directory.resolve(DIRECTORY_WEBINF);
-
-    if (Files.exists(webinfDir))
-    {
-      Path classesDir = webinfDir.resolve(DIRECTORY_CLASSES);
-
-      if (Files.exists(classesDir))
-      {
-        urls.add(classesDir.toUri().toURL());
-      }
-
-      Path libDir = webinfDir.resolve(DIRECTORY_DEPENDENCIES);
-
-      if (Files.exists(libDir))
-      {
-        for (Path f : Files.newDirectoryStream(libDir, GLOB_JAR))
-        {
-          urls.add(f.toUri().toURL());
-        }
-      }
-    }
-
-    //J-
-    return new DefaultPluginClassLoader(
-      urls.toArray(new URL[urls.size()]),
-      parentClassLoader
-    );
-    //J+
-  }
-
   /**
    * Method description
    *
@@ -313,7 +242,7 @@ public final class PluginProcessor
 
     PluginWrapper plugin =
       createPluginWrapper(createParentPluginClassLoader(classLoader, parents),
-        smp.getPath());
+        smp);
 
     if (plugin != null)
     {
@@ -335,7 +264,7 @@ public final class PluginProcessor
     ClassLoader classLoader, List<PluginNode> nodes)
     throws IOException
   {
-    
+
     // TODO fix plugin loading order
     for (PluginNode node : nodes)
     {
@@ -402,6 +331,91 @@ public final class PluginProcessor
     return paths.build();
   }
 
+  /**
+   * Method description
+   *
+   *
+   * @param parentClassLoader
+   * @param directory
+   * @param smp
+   *
+   * @return
+   *
+   * @throws IOException
+   */
+  private ClassLoader createClassLoader(ClassLoader parentClassLoader,
+    ExplodedSmp smp)
+    throws IOException
+  {
+    List<URL> urls = new ArrayList<>();
+
+    Path metaDir = smp.getPath().resolve(DIRECTORY_METAINF);
+
+    if (!Files.exists(metaDir))
+    {
+      throw new FileNotFoundException("could not find META-INF directory");
+    }
+
+    Path linkDir = smp.getPath().resolve(DIRECTORY_LINK);
+
+    if (!Files.exists(linkDir))
+    {
+      Files.createDirectory(linkDir);
+    }
+
+    Path linkMetaDir = linkDir.resolve(DIRECTORY_METAINF);
+
+    if (!Files.exists(linkMetaDir))
+    {
+      Files.deleteIfExists(linkMetaDir);
+      Files.createSymbolicLink(linkMetaDir, linkMetaDir.relativize(metaDir));
+    }
+
+    urls.add(linkDir.toUri().toURL());
+
+    Path webinfDir = smp.getPath().resolve(DIRECTORY_WEBINF);
+
+    if (Files.exists(webinfDir))
+    {
+      Path classesDir = webinfDir.resolve(DIRECTORY_CLASSES);
+
+      if (Files.exists(classesDir))
+      {
+        urls.add(classesDir.toUri().toURL());
+      }
+
+      Path libDir = webinfDir.resolve(DIRECTORY_DEPENDENCIES);
+
+      if (Files.exists(libDir))
+      {
+        for (Path f : Files.newDirectoryStream(libDir, GLOB_JAR))
+        {
+          urls.add(f.toUri().toURL());
+        }
+      }
+    }
+
+    ClassLoader classLoader;
+    URL[] urlArray = urls.toArray(new URL[urls.size()]);
+    Plugin plugin = smp.getPlugin();
+
+    if (smp.getPlugin().isChildFirstClassLoader())
+    {
+      logger.debug("create child fist classloader for plugin {}",
+        plugin.getInformation().getId());
+      classLoader = new ChildFirstPluginClassLoader(urlArray,
+        parentClassLoader);
+    }
+    else
+    {
+      logger.debug("create parent fist classloader for plugin {}",
+        plugin.getInformation().getId());
+      classLoader = new DefaultPluginClassLoader(urlArray, parentClassLoader);
+    }
+
+    return classLoader;
+  }
+
   /**
    * Method description
    *
@@ -413,6 +427,37 @@ public final class PluginProcessor
     return new SimpleDateFormat(FORMAT_DATE).format(new Date());
   }
 
+  /**
+   * Method description
+   *
+   *
+   * @param root
+   * @param parents
+   *
+   * @return
+   */
+  private ClassLoader createParentPluginClassLoader(ClassLoader root,
+    List<ClassLoader> parents)
+  {
+    ClassLoader result;
+    int size = parents.size();
+
+    if (size == 0)
+    {
+      result = root;
+    }
+    else if (size == 1)
+    {
+      result = parents.get(0);
+    }
+    else
+    {
+      result = new MultiParentClassLoader(parents);
+    }
+
+    return result;
+  }
+
   /**
    * Method description
    *
@@ -445,62 +490,32 @@ public final class PluginProcessor
     }
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @param root
-   * @param parents
-   *
-   * @return
-   */
-  private ClassLoader createParentPluginClassLoader(ClassLoader root,
-    List<ClassLoader> parents)
-  {
-    ClassLoader result;
-    int size = parents.size();
-
-    if (size == 0)
-    {
-      result = root;
-    }
-    else if (size == 1)
-    {
-      result = parents.get(0);
-    }
-    else
-    {
-      result = new MultiParentClassLoader(parents);
-    }
-
-    return result;
-  }
-
   /**
    * Method description
    *
    *
    * @param classLoader
    * @param directory
+   * @param smp
    *
    * @return
    *
    * @throws IOException
    */
   private PluginWrapper createPluginWrapper(ClassLoader classLoader,
-    Path directory)
+    ExplodedSmp smp)
     throws IOException
   {
     PluginWrapper wrapper = null;
-    Path descriptor = directory.resolve(PluginConstants.FILE_DESCRIPTOR);
+    Path descriptor = smp.getPath().resolve(PluginConstants.FILE_DESCRIPTOR);
 
     if (Files.exists(descriptor))
     {
-      ClassLoader cl = createClassLoader(classLoader, directory);
+      ClassLoader cl = createClassLoader(classLoader, smp);
 
       Plugin plugin = createPlugin(cl, descriptor);
 
-      wrapper = new PluginWrapper(plugin, cl, directory);
+      wrapper = new PluginWrapper(plugin, cl, smp.getPath());
     }
     else
     {

scm-webapp/src/test/java/sonia/scm/plugin/ExplodedSmpTest.java

@@ -135,7 +135,7 @@ public class ExplodedSmpTest
     info.setArtifactId(artifactId);
     info.setVersion(version);
 
-    Plugin plugin = new Plugin(info, null, null, Sets.newSet(dependencies));
+    Plugin plugin = new Plugin(info, null, null, false, Sets.newSet(dependencies));
 
     return new ExplodedSmp(null, plugin);
   }

scm-webapp/src/test/java/sonia/scm/plugin/PluginTreeTest.java

@@ -72,7 +72,7 @@ public class PluginTreeTest
     PluginCondition condition = new PluginCondition("999",
                                   new ArrayList<String>(), "hit");
     Plugin plugin = new Plugin(createInfo("a", "b", "1"), null, condition,
-                      null);
+                      false, null);
     ExplodedSmp smp = createSmp(plugin);
 
     new PluginTree(smp).getRootNodes();
@@ -186,7 +186,7 @@ public class PluginTreeTest
   private ExplodedSmp createSmp(String name) throws IOException
   {
     return createSmp(new Plugin(createInfo(name, name, "1.0.0"), null, null,
-      null));
+      false, null));
   }
 
   /**
@@ -212,7 +212,7 @@ public class PluginTreeTest
     }
 
     Plugin plugin = new Plugin(createInfo(name, name, "1"), null, null,
-                      dependencySet);
+                      false, dependencySet);
 
     return createSmp(plugin);
   }