manifest addon loading

common/addons/manifest-addon-loader/build.gradle.kts

@@ -1,2 +1,4 @@
 dependencies {
+    "shadedApi"("commons-io:commons-io:2.6")
+    "shadedImplementation"("com.dfsek.tectonic:yaml:2.1.2")
 }

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/impl/ManifestAddonClassLoader.java

@@ -0,0 +1,15 @@
+package com.dfsek.terra.addons.manifest.impl;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+
+
+public class ManifestAddonClassLoader extends URLClassLoader {
+    static {
+        ClassLoader.registerAsParallelCapable();
+    }
+    
+    public ManifestAddonClassLoader(URL[] urls, ClassLoader parent) {
+        super(urls, parent);
+    }
+}

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/impl/ManifestAddonLoader.java

@@ -2,14 +2,27 @@ package com.dfsek.terra.addons.manifest.impl;
 
 import ca.solostudios.strata.version.Version;
 import ca.solostudios.strata.version.VersionRange;
+import com.dfsek.tectonic.exception.LoadException;
 import com.dfsek.tectonic.loading.ConfigLoader;
+import com.dfsek.tectonic.yaml.YamlConfiguration;
 
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.lang.reflect.InvocationTargetException;
+import java.net.URL;
+import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.Collections;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.stream.Collectors;
 
+import com.dfsek.terra.addons.manifest.impl.config.AddonManifest;
 import com.dfsek.terra.addons.manifest.impl.config.WebsiteConfig;
 import com.dfsek.terra.addons.manifest.impl.config.loaders.VersionLoader;
 import com.dfsek.terra.addons.manifest.impl.config.loaders.VersionRangeLoader;
+import com.dfsek.terra.addons.manifest.impl.exception.AddonException;
+import com.dfsek.terra.addons.manifest.impl.exception.ManifestException;
+import com.dfsek.terra.addons.manifest.impl.exception.ManifestNotPresentException;
 import com.dfsek.terra.api.addon.BaseAddon;
 import com.dfsek.terra.api.addon.bootstrap.BootstrapBaseAddon;
 
@@ -20,8 +33,54 @@ public class ManifestAddonLoader implements BootstrapBaseAddon {
         ConfigLoader manifestLoader = new ConfigLoader();
         manifestLoader.registerLoader(Version.class, new VersionLoader())
                       .registerLoader(VersionRange.class, new VersionRangeLoader())
-                .registerLoader(WebsiteConfig.class, WebsiteConfig::new);
+                      .registerLoader(WebsiteConfig.class, WebsiteConfig::new);
-        return Collections.emptySet();
+        
+        try {
+            return Files.walk(addonsFolder, 1)
+                        .filter(path -> path.toFile().isFile() && path.getFileName().endsWith(".jar"))
+                        .flatMap(path -> {
+                            try {
+                                JarFile jar = new JarFile(path.toFile());
+                    
+                                JarEntry manifestEntry = jar.getJarEntry("terra.addon.yml");
+                                if(manifestEntry == null) {
+                                    throw new ManifestNotPresentException("Addon " + path + " does not contain addon manifest.");
+                                }
+                    
+                                try {
+                                    AddonManifest manifest = manifestLoader.load(new AddonManifest(),
+                                                                                 new YamlConfiguration(jar.getInputStream(manifestEntry),
+                                                                                                       "terra.addon.yml"));
+                        
+                                    ManifestAddonClassLoader loader = new ManifestAddonClassLoader(new URL[]{ path.toUri().toURL() },
+                                                                                                   parent);
+                        
+                                    return manifest.getEntryPoints().stream().map(entryPoint -> {
+                                        try {
+                                            Object in = loader.loadClass(entryPoint).getConstructor().newInstance();
+                                            if(!(in instanceof BaseAddon)) {
+                                                throw new AddonException(in.getClass() + " does not extend " + BaseAddon.class);
+                                            }
+                                            return (BaseAddon) in;
+                                        } catch(InvocationTargetException e) {
+                                            throw new AddonException("Exception occurred while instantiating addon: ", e);
+                                        } catch(NoSuchMethodException | IllegalAccessException | InstantiationException e) {
+                                            throw new AddonException("No valid default constructor found in entry point " + entryPoint);
+                                        } catch(ClassNotFoundException e) {
+                                            throw new AddonException("Entry point " + entryPoint + " not found in JAR.");
+                                        }
+                                    });
+                        
+                                } catch(LoadException e) {
+                                    throw new ManifestException("Failed to load addon manifest", e);
+                                }
+                            } catch(IOException e) {
+                                throw new UncheckedIOException(e);
+                            }
+                        }).collect(Collectors.toList());
+        } catch(IOException e) {
+            throw new UncheckedIOException(e);
+        }
     }
     
     @Override

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/impl/exception/AddonException.java

@@ -0,0 +1,11 @@
+package com.dfsek.terra.addons.manifest.impl.exception;
+
+public class AddonException extends RuntimeException {
+    public AddonException(String message) {
+        super(message);
+    }
+    
+    public AddonException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/impl/exception/ManifestException.java

@@ -0,0 +1,11 @@
+package com.dfsek.terra.addons.manifest.impl.exception;
+
+public class ManifestException extends AddonException{
+    public ManifestException(String message) {
+        super(message);
+    }
+    
+    public ManifestException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/impl/exception/ManifestNotPresentException.java

@@ -0,0 +1,11 @@
+package com.dfsek.terra.addons.manifest.impl.exception;
+
+public class ManifestNotPresentException extends ManifestException{
+    public ManifestNotPresentException(String message) {
+        super(message);
+    }
+    
+    public ManifestNotPresentException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}