Implement plugin recognizing

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/PluginManager.kt

@@ -60,6 +60,7 @@ object PluginManager {
     // region LOADING
 
     private fun <P : Plugin, D : PluginDescription> PluginLoader<P, D>.loadPluginNoEnable(description: D): P {
+        // TODO: 2020/5/23 HANDLE INITIALIZATION EXCEPTION
         return this.load(description).also { resolvedPlugins.add(it) }
     }
 

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/builtin/JarPluginLoader.kt

@@ -6,7 +6,10 @@ import net.mamoe.mirai.console.plugins.AbstractFilePluginLoader
 import net.mamoe.mirai.console.plugins.PluginLoadException
 import net.mamoe.mirai.console.plugins.PluginsLoader
 import net.mamoe.mirai.utils.MiraiLogger
+import net.mamoe.mirai.utils.error
+import net.mamoe.yamlkt.Yaml
 import java.io.File
+import java.net.URL
 import kotlin.coroutines.CoroutineContext
 import kotlin.reflect.full.createInstance
 
@@ -38,14 +41,19 @@ object JarPluginLoader : AbstractFilePluginLoader<JvmPlugin, JvmPluginDescriptio
     override fun getPluginDescription(plugin: JvmPlugin): JvmPluginDescription = plugin.description
 
     override fun Sequence<File>.mapToDescription(): List<JvmPluginDescription> {
-        TODO(
-            """
-            CHECK IS JAR FILE AND CAN BE READ
-            READ JAR FILE, EXTRACT PLUGIN DESCRIPTION
-            SET JvmPluginDescription._file
-            RETURN PLUGIN 
-        """.trimIndent()
-        )
+        return this.associateWith { URL("jar:${it.absolutePath}!/plugin.yml") }.mapNotNull { (file, url) ->
+            kotlin.runCatching {
+                url.readText()
+            }.fold(
+                onSuccess = { yaml ->
+                    Yaml.nonStrict.parse(JvmPluginDescription.serializer(), yaml)
+                },
+                onFailure = {
+                    logger.error("Cannot load plugin file ${file.name}", it)
+                    null
+                }
+            )?.also { it._file = file }
+        }
     }
 
     @Throws(PluginLoadException::class)
@@ -68,10 +76,7 @@ object JarPluginLoader : AbstractFilePluginLoader<JvmPlugin, JvmPluginDescriptio
         } else main.onLoad()
         main
     }.getOrElse {
-        throw PluginLoadException(
-            "Exception while loading ${description.name}",
-            it
-        )
+        throw PluginLoadException("Exception while loading ${description.name}", it)
     }
 
     override fun enable(plugin: JvmPlugin) {

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/builtin/JvmPluginDescription.kt

@@ -15,9 +15,10 @@ class JvmPluginDescription internal constructor(
     override val name: String,
     @SerialName("main")
     val mainClassName: String,
-    override val author: String,
+    override val author: String = "",
     override val version: String,
-    override val info: String,
+    override val info: String = "",
+    @SerialName("depends")
     override val dependencies: List<PluginDependency>
 ) : PluginDescription, FilePluginDescription {
 

backend/mirai-console/src/main/kotlin/net/mamoe/mirai/console/plugins/description.kt

@@ -9,17 +9,32 @@
 
 package net.mamoe.mirai.console.plugins
 
-import kotlinx.serialization.Serializable
+import kotlinx.serialization.*
+import kotlinx.serialization.builtins.serializer
 import java.io.File
 
 
 /** 插件类型 */
+@Serializable(with = PluginKind.Serializer::class)
 enum class PluginKind {
     /** 表示此插件提供一个 [PluginLoader], 应在加载其他 [NORMAL] 类型插件前加载 */
     LOADER,
 
     /** 表示此插件为一个通常的插件, 按照正常的依赖关系加载. */
-    NORMAL
+    NORMAL;
+
+    companion object Serializer : KSerializer<PluginKind> {
+        override val descriptor: SerialDescriptor get() = String.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): PluginKind {
+            val name = String.serializer().deserialize(decoder)
+            return values().firstOrNull { it.name.equals(name, ignoreCase = true) } ?: NORMAL
+        }
+
+        override fun serialize(encoder: Encoder, value: PluginKind) {
+            return String.serializer().serialize(encoder, value.toString())
+        }
+    }
 }
 
 /**