Add WorktimeLimiter API, basic /parcel clear functionality

15 files changed, 415 insertions, 104 deletions

diff --git a/src/main/kotlin/io/dico/parcels2/Options.kt b/src/main/kotlin/io/dico/parcels2/Options.kt
index 41b3568..05df718 100644
--- a/src/main/kotlin/io/dico/parcels2/Options.kt
+++ b/src/main/kotlin/io/dico/parcels2/Options.kt
@@ -2,7 +2,7 @@ package io.dico.parcels2
 
 
 import com.fasterxml.jackson.annotation.JsonIgnore
-import io.dico.parcels2.blockvisitor.BlockVisitorOptions
+import io.dico.parcels2.blockvisitor.TickWorktimeOptions
 import io.dico.parcels2.storage.Storage
 import io.dico.parcels2.storage.StorageFactory
 import io.dico.parcels2.storage.yamlObjectMapper
@@ -19,6 +19,7 @@ class Options {
     var worlds: Map<String, WorldOptions> = HashMap()
         private set
     var storage: StorageOptions = StorageOptions("postgresql", DataConnectionOptions())
+    var tickWorktime: TickWorktimeOptions = TickWorktimeOptions(30, 1)
 
     fun addWorld(name: String, options: WorldOptions) = (worlds as MutableMap).put(name, options)
 
@@ -40,8 +41,7 @@ data class WorldOptions(var gameMode: GameMode? = GameMode.CREATIVE,
                         var blockMobSpawning: Boolean = true,
                         var blockedItems: Set<Material> = EnumSet.of(Material.FLINT_AND_STEEL, Material.SNOWBALL),
                         var axisLimit: Int = 10,
-                        var generator: GeneratorOptions = DefaultGeneratorOptions(),
-                        var blockVisitor: BlockVisitorOptions = BlockVisitorOptions()) {
+                        var generator: GeneratorOptions = DefaultGeneratorOptions()) {
 
 }
 
@@ -73,7 +73,8 @@ class StorageOptions(val dialect: String,
                      val options: Any) {
 
     @get:JsonIgnore
-    val factory = StorageFactory.getFactory(dialect) ?: throw IllegalArgumentException("Invalid storage dialect: $dialect")
+    val factory = StorageFactory.getFactory(dialect)
+        ?: throw IllegalArgumentException("Invalid storage dialect: $dialect")
 
     fun newStorageInstance(): Storage = factory.newStorageInstance(dialect, options)
 
diff --git a/src/main/kotlin/io/dico/parcels2/ParcelWorld.kt b/src/main/kotlin/io/dico/parcels2/ParcelWorld.kt
index d4287af..9a50b31 100644
--- a/src/main/kotlin/io/dico/parcels2/ParcelWorld.kt
+++ b/src/main/kotlin/io/dico/parcels2/ParcelWorld.kt
@@ -20,7 +20,7 @@ import kotlin.coroutines.experimental.buildSequence
 import kotlin.reflect.jvm.javaMethod
 import kotlin.reflect.jvm.kotlinFunction
 
-class Worlds(private val plugin: ParcelsPlugin) {
+class Worlds(val plugin: ParcelsPlugin) {
     val worlds: Map<String, ParcelWorld> get() = _worlds
     private val _worlds: MutableMap<String, ParcelWorld> = HashMap()
 
diff --git a/src/main/kotlin/io/dico/parcels2/ParcelsPlugin.kt b/src/main/kotlin/io/dico/parcels2/ParcelsPlugin.kt
index fd4270f..8f0e89e 100644
--- a/src/main/kotlin/io/dico/parcels2/ParcelsPlugin.kt
+++ b/src/main/kotlin/io/dico/parcels2/ParcelsPlugin.kt
@@ -3,6 +3,8 @@ package io.dico.parcels2
 import io.dico.dicore.Registrator
 import io.dico.dicore.command.EOverridePolicy
 import io.dico.dicore.command.ICommandDispatcher
+import io.dico.parcels2.blockvisitor.TickWorktimeLimiter
+import io.dico.parcels2.blockvisitor.WorktimeLimiter
 import io.dico.parcels2.command.getParcelCommands
 import io.dico.parcels2.listener.ParcelEntityTracker
 import io.dico.parcels2.listener.ParcelListeners
@@ -29,8 +31,7 @@ class ParcelsPlugin : JavaPlugin() {
     lateinit var entityTracker: ParcelEntityTracker; private set
     private var listeners: ParcelListeners? = null
     private var cmdDispatcher: ICommandDispatcher? = null
-
-    val mainThreadDispatcher = Executor { server.scheduler.runTask(this, it) }.asCoroutineDispatcher()
+    val worktimeLimiter: WorktimeLimiter by lazy { TickWorktimeLimiter(this, options) }
 
     override fun onEnable() {
         plogger.info("Debug enabled: ${plogger.isDebugEnabled}")
diff --git a/src/main/kotlin/io/dico/parcels2/WorldGenerator.kt b/src/main/kotlin/io/dico/parcels2/WorldGenerator.kt
index 6bd214b..e61788c 100644
--- a/src/main/kotlin/io/dico/parcels2/WorldGenerator.kt
+++ b/src/main/kotlin/io/dico/parcels2/WorldGenerator.kt
@@ -1,9 +1,8 @@
 package io.dico.parcels2
 
-import io.dico.parcels2.util.Vec2i
-import io.dico.parcels2.util.clamp
-import io.dico.parcels2.util.even
-import io.dico.parcels2.util.umod
+import io.dico.parcels2.blockvisitor.JobData
+import io.dico.parcels2.blockvisitor.RegionTraversal
+import io.dico.parcels2.util.*
 import org.bukkit.*
 import org.bukkit.Bukkit.createBlockData
 import org.bukkit.block.Biome
@@ -51,6 +50,8 @@ abstract class ParcelGenerator : ChunkGenerator(), ParcelProvider {
 
     abstract fun getBlocks(parcel: Parcel, yRange: IntRange = 0..255): Iterator<Block>
 
+    abstract fun clearParcel(parcel: Parcel): JobData
+
 }
 
 interface GeneratorFactory {
@@ -78,6 +79,9 @@ interface GeneratorFactory {
 class DefaultParcelGenerator(val worlds: Worlds, val name: String, private val o: DefaultGeneratorOptions) : ParcelGenerator() {
     override val world: ParcelWorld by lazy { worlds.getWorld(name)!! }
     override val factory = Factory
+    val worktimeLimiter = worlds.plugin.worktimeLimiter
+    val maxHeight by lazy { world.world.maxHeight }
+    val airType = worlds.plugin.server.createBlockData(Material.AIR)
 
     companion object Factory : GeneratorFactory {
         override val name get() = "default"
@@ -260,4 +264,28 @@ class DefaultParcelGenerator(val worlds: Worlds, val name: String, private val o
         }
     }
 
+    override fun clearParcel(parcel: Parcel) = worktimeLimiter.submit {
+        val bottom = getBottomCoord(parcel)
+        val region = Region(Vec3i(bottom.x, 0, bottom.z), Vec3i(o.parcelSize, maxHeight + 1, o.parcelSize))
+        val blocks = RegionTraversal.XZY.regionTraverser(region)
+        val blockCount = region.blockCount.toDouble()
+
+        val world = world.world
+        val floorHeight = o.floorHeight
+        val airType = airType; val floorType = o.floorType; val fillType = o.fillType
+
+        for ((index, vec) in blocks.withIndex()) {
+            markSuspensionPoint()
+            val y = vec.y
+            val blockType = when {
+                y > floorHeight -> airType
+                y == floorHeight -> floorType
+                else -> fillType
+            }
+            world[vec].blockData = blockType
+            setProgress((index + 1) / blockCount)
+        }
+
+    }
+
 }
\ No newline at end of file
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/Attachables.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/Attachables.kt
new file mode 100644
index 0000000..c046940
--- /dev/null
+++ b/src/main/kotlin/io/dico/parcels2/blockvisitor/Attachables.kt
@@ -0,0 +1,67 @@
+package io.dico.parcels2.blockvisitor
+
+import org.bukkit.Material
+import org.bukkit.Material.*
+import java.util.*
+
+val attachables: Set<Material> = EnumSet.of(
+    ACACIA_DOOR,
+    ACTIVATOR_RAIL,
+    BIRCH_DOOR,
+    BROWN_MUSHROOM,
+    CACTUS,
+    CAKE,
+    WHITE_CARPET, ORANGE_CARPET, MAGENTA_CARPET, LIGHT_BLUE_CARPET, YELLOW_CARPET, LIME_CARPET, PINK_CARPET, GRAY_CARPET, LIGHT_GRAY_CARPET, CYAN_CARPET, PURPLE_CARPET, BLUE_CARPET, BROWN_CARPET, GREEN_CARPET, RED_CARPET, BLACK_CARPET,
+    CARROT,
+    COCOA,
+    WHEAT,
+    DARK_OAK_DOOR,
+    DEAD_BUSH,
+    DETECTOR_RAIL,
+    REPEATER,
+    TALL_GRASS, TALL_SEAGRASS,
+    DRAGON_EGG,
+    FIRE,
+    FLOWER_POT,
+    OAK_PRESSURE_PLATE, BIRCH_PRESSURE_PLATE, SPRUCE_PRESSURE_PLATE, JUNGLE_PRESSURE_PLATE, ACACIA_PRESSURE_PLATE, DARK_OAK_PRESSURE_PLATE,
+    STONE_PRESSURE_PLATE, LIGHT_WEIGHTED_PRESSURE_PLATE, HEAVY_WEIGHTED_PRESSURE_PLATE,
+    IRON_DOOR,
+    OAK_DOOR, BIRCH_DOOR, SPRUCE_DOOR, JUNGLE_DOOR, ACACIA_DOOR, DARK_OAK_DOOR,
+    OAK_BUTTON, BIRCH_BUTTON, SPRUCE_BUTTON, JUNGLE_BUTTON, ACACIA_BUTTON, DARK_OAK_BUTTON,
+    STONE_BUTTON,
+    OAK_TRAPDOOR, BIRCH_TRAPDOOR, SPRUCE_TRAPDOOR, JUNGLE_TRAPDOOR, ACACIA_TRAPDOOR, DARK_OAK_TRAPDOOR,
+    IRON_TRAPDOOR,
+    LADDER,
+    LEVER,
+    MELON_STEM,
+    NETHER_WART,
+    PISTON,
+    STICKY_PISTON,
+    NETHER_PORTAL,
+    POTATO,
+    POWERED_RAIL,
+    PUMPKIN_STEM,
+    RAIL,
+    COMPARATOR,
+    REDSTONE_TORCH,
+    REDSTONE_WIRE,
+    RED_MUSHROOM,
+    SUNFLOWER,
+    FLOWER_POT,
+    CHORUS_FLOWER,
+    OAK_SAPLING, BIRCH_SAPLING, SPRUCE_SAPLING, JUNGLE_SAPLING, ACACIA_SAPLING, DARK_OAK_SAPLING,
+    SIGN,
+    SNOW,
+    SPRUCE_DOOR,
+    STONE_BUTTON,
+    SUGAR_CANE,
+    TORCH,
+    TRIPWIRE,
+    TRIPWIRE_HOOK,
+    VINE,
+    WHITE_BANNER, ORANGE_BANNER, MAGENTA_BANNER, LIGHT_BLUE_BANNER, YELLOW_BANNER, LIME_BANNER, PINK_BANNER, GRAY_BANNER, LIGHT_GRAY_BANNER, CYAN_BANNER, PURPLE_BANNER, BLUE_BANNER, BROWN_BANNER, GREEN_BANNER, RED_BANNER, BLACK_BANNER,
+    WHITE_WALL_BANNER, ORANGE_WALL_BANNER, MAGENTA_WALL_BANNER, LIGHT_BLUE_WALL_BANNER, YELLOW_WALL_BANNER, LIME_WALL_BANNER, PINK_WALL_BANNER, GRAY_WALL_BANNER, LIGHT_GRAY_WALL_BANNER, CYAN_WALL_BANNER, PURPLE_WALL_BANNER, BLUE_WALL_BANNER, BROWN_WALL_BANNER, GREEN_WALL_BANNER, RED_WALL_BANNER, BLACK_WALL_BANNER,
+    WALL_SIGN,
+    LILY_PAD,
+    DANDELION
+);
\ No newline at end of file
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitor.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitor.kt
deleted file mode 100644
index 12433e1..0000000
--- a/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitor.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-package io.dico.parcels2.blockvisitor
-
-import io.dico.dicore.task.IteratorTask
-
-abstract class BlockVisitor<T>(iterator: Iterator<T>?) : IteratorTask<T>(iterator)
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitorManager.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitorManager.kt
deleted file mode 100644
index a26328f..0000000
--- a/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitorManager.kt
+++ /dev/null
@@ -1,52 +0,0 @@
-package io.dico.parcels2.blockvisitor
-
-import io.dico.parcels2.util.MutableVec3i
-import io.dico.parcels2.util.Region
-import kotlinx.coroutines.experimental.Deferred
-import org.bukkit.block.Block
-import org.bukkit.plugin.Plugin
-import kotlin.coroutines.experimental.SequenceBuilder
-import kotlin.coroutines.experimental.buildIterator
-
-typealias BlockProcessor = (Block) -> Boolean
-
-class BlockVisitorManager(val plugin: Plugin, var options: BlockVisitorOptions) {
-
-
-    fun doOperationSynchronously(region: Region, processor: BlockProcessor): Deferred<Unit> {
-
-
-    }
-
-
-}
-
-class RegionOperation(val region: Region, val processor: BlockProcessor) {
-
-    fun process(maxMillis: Int) {
-
-    }
-
-
-}
-
-enum class RegionTraversal(private val builder: suspend SequenceBuilder<MutableVec3i>.(Region) -> Unit) {
-    XZY({ region ->
-        val origin = region.origin
-        val result = MutableVec3i(origin.x, origin.y, origin.z)
-
-        val size = region.size
-
-        repeat(size.y) { y ->
-            repeat()
-
-            result.y++
-        }
-
-    })
-
-    ;
-
-    fun regionTraverser(region: Region) = Iterable { buildIterator { builder(region) } }
-
-}
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitorOptions.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitorOptions.kt
deleted file mode 100644
index e4ebf48..0000000
--- a/src/main/kotlin/io/dico/parcels2/blockvisitor/BlockVisitorOptions.kt
+++ /dev/null
@@ -1,3 +0,0 @@
-package io.dico.parcels2.blockvisitor
-
-data class BlockVisitorOptions(var pauseTicks: Int = 1, var workMillis: Int = 30)
\ No newline at end of file
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/RegionTraversal.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/RegionTraversal.kt
new file mode 100644
index 0000000..0e7d217
--- /dev/null
+++ b/src/main/kotlin/io/dico/parcels2/blockvisitor/RegionTraversal.kt
@@ -0,0 +1,30 @@
+package io.dico.parcels2.blockvisitor
+
+import io.dico.parcels2.util.Region
+import io.dico.parcels2.util.Vec3i
+import kotlin.coroutines.experimental.SequenceBuilder
+import kotlin.coroutines.experimental.buildIterator
+
+enum class RegionTraversal(private val builder: suspend SequenceBuilder<Vec3i>.(Region) -> Unit) {
+    XZY({ region ->
+        val origin = region.origin
+        val size = region.size
+
+        repeat(size.y) { y ->
+            repeat(size.z) { z ->
+                repeat(size.x) { x ->
+                    yield(origin.add(x, y, z))
+                }
+            }
+        }
+
+    }),
+
+    ;
+
+    fun regionTraverser(region: Region) = Iterable { buildIterator { builder(region) } }
+
+}
+
+
+
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/Schematic.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/Schematic.kt
index b48e4f1..1c01571 100644
--- a/src/main/kotlin/io/dico/parcels2/blockvisitor/Schematic.kt
+++ b/src/main/kotlin/io/dico/parcels2/blockvisitor/Schematic.kt
@@ -1,13 +1,52 @@
 package io.dico.parcels2.blockvisitor
 
+import io.dico.parcels2.util.Region
 import io.dico.parcels2.util.Vec3i
+import io.dico.parcels2.util.get
+import org.bukkit.World
 import org.bukkit.block.data.BlockData
 
-class Schematic(val origin: Vec3i, val size: Vec3i) {
-    private var data: Array<BlockData>? = null
+class Schematic {
+    val size: Vec3i get() = _size!!
+    private var _size: Vec3i? = null
+        set(value) {
+            field?.let { throw IllegalStateException() }
+            field = value
+        }
 
+    private var _data: Array<BlockData?>? = null
+    //private var extra: Map<Vec3i, (Block) -> Unit>? = null
+    private var isLoaded = false; private set
 
+    fun getLoadTask(world: World, region: Region): TimeLimitedTask = {
+        val size = region.size.also { _size = it }
+        val data = arrayOfNulls<BlockData>(region.blockCount).also { _data = it }
+        //val extra = mutableMapOf<Vec3i, (Block) -> Unit>().also { extra = it }
+        val blocks = RegionTraversal.XZY.regionTraverser(region)
 
+        for ((index, vec) in blocks.withIndex()) {
+            markSuspensionPoint()
+            val block = world[vec]
+            if (block.y > 255) continue
+            val blockData = block.blockData
+            data[index] = blockData
+        }
 
+        isLoaded = true
+    }
 
-}
\ No newline at end of file
+    fun getPasteTask(world: World, position: Vec3i): TimeLimitedTask = {
+        if (!isLoaded) throw IllegalStateException()
+        val region = Region(position, _size!!)
+        val blocks = RegionTraversal.XZY.regionTraverser(region)
+        val data = _data!!
+
+        for ((index, vec) in blocks.withIndex()) {
+            markSuspensionPoint()
+            val block = world[vec]
+            if (block.y > 255) continue
+            data[index]?.let { block.blockData = it }
+        }
+    }
+
+}
diff --git a/src/main/kotlin/io/dico/parcels2/blockvisitor/WorktimeLimiter.kt b/src/main/kotlin/io/dico/parcels2/blockvisitor/WorktimeLimiter.kt
new file mode 100644
index 0000000..2394da0
--- /dev/null
+++ b/src/main/kotlin/io/dico/parcels2/blockvisitor/WorktimeLimiter.kt
@@ -0,0 +1,207 @@
+package io.dico.parcels2.blockvisitor
+
+import io.dico.parcels2.Options
+import kotlinx.coroutines.experimental.CoroutineStart
+import kotlinx.coroutines.experimental.Job
+import kotlinx.coroutines.experimental.asCoroutineDispatcher
+import kotlinx.coroutines.experimental.launch
+import org.bukkit.plugin.Plugin
+import org.bukkit.scheduler.BukkitTask
+import java.util.*
+import java.util.concurrent.Executor
+import kotlin.coroutines.experimental.Continuation
+import kotlin.coroutines.experimental.ContinuationInterceptor
+import kotlin.coroutines.experimental.intrinsics.COROUTINE_SUSPENDED
+import kotlin.coroutines.experimental.intrinsics.suspendCoroutineUninterceptedOrReturn
+
+interface WorktimeLimiter {
+    /**
+     * Submit a task that should be run synchronously, but limited such that it does not stall the server
+     * a bunch
+     */
+    fun submit(job: TimeLimitedTask): JobData
+
+    /**
+     * A task should call this frequently during its execution, such that the timer can suspend it when necessary.
+     */
+    suspend fun markSuspensionPoint()
+
+    /**
+     * A task should call this method to indicate its progress
+     */
+    fun setProgress(progress: Double)
+}
+
+typealias TimeLimitedTask = suspend WorktimeLimiter.() -> Unit
+
+interface JobData {
+    val job: Job?
+    val isComplete: Boolean
+    val progress: Double?
+
+    /**
+     * Calls the given [block] whenever the progress is updated,
+     * if [minInterval] milliseconds expired since the last call.
+     *
+     * The first call occurs after at least [minDelay] milliseconds in a likewise manner.
+     * Repeated invocations of this method result in an [IllegalStateException]
+     */
+    fun onProgressUpdate(minDelay: Int, minInterval: Int, block: JobUpdateListener): JobData
+    val isUpdateBlockPresent: Boolean
+
+    /**
+     * Calls the given [block] when this job completes.
+     */
+    fun onCompleted(block: JobUpdateListener): JobData
+}
+
+typealias JobUpdateListener = JobData.(Double) -> Unit
+
+class JobDataImpl(val task: TimeLimitedTask) : JobData {
+    override var job: Job? = null
+        set(value) {
+            field?.let { throw IllegalStateException() }
+            field = value!!
+            value.invokeOnCompletion { onCompletedBlock?.invoke(this, 1.0) }
+        }
+
+    var next: Continuation<Unit>? = null
+
+    override var progress: Double? = null
+        set(value) {
+            field = value
+            doProgressUpdate()
+        }
+
+    private fun doProgressUpdate() {
+        val progressUpdate = progressUpdateBlock ?: return
+        val time = System.currentTimeMillis()
+        if (time > lastUpdateTime + progressUpdateInterval) {
+            progressUpdate(progress!!)
+            lastUpdateTime = time
+        }
+    }
+
+    override val isUpdateBlockPresent get() = progressUpdateBlock != null
+    private var progressUpdateBlock: JobUpdateListener? = null
+    private var progressUpdateInterval: Int = 0
+    private var lastUpdateTime: Long = 0L
+    override fun onProgressUpdate(minDelay: Int, minInterval: Int, block: JobUpdateListener): JobDataImpl {
+        progressUpdateBlock?.let { throw IllegalStateException() }
+        progressUpdateBlock = block
+        progressUpdateInterval = minInterval
+        lastUpdateTime = System.currentTimeMillis() + minDelay - minInterval
+        return this
+    }
+
+    override val isComplete get() = job?.isCompleted == true
+    private var onCompletedBlock: JobUpdateListener? = null
+    override fun onCompleted(block: JobUpdateListener): JobDataImpl {
+        onCompletedBlock?.let { throw IllegalStateException() }
+        onCompletedBlock = block
+        return this
+    }
+
+}
+
+/**
+ * An object that controls one or more jobs, ensuring that they don't stall the server too much.
+ * The amount of milliseconds that can accumulate each server tick is configurable
+ */
+class TickWorktimeLimiter(private val plugin: Plugin, private val optionsRoot: Options) : WorktimeLimiter {
+    // Coroutine dispatcher for jobs
+    private val dispatcher = Executor(Runnable::run).asCoroutineDispatcher()
+    // union of Continuation<Unit> and suspend WorktimeLimited.() -> Unit
+    private var jobs = LinkedList<JobDataImpl>()
+    // The currently registered bukkit scheduler task
+    private var task: BukkitTask? = null
+    // The data associated with the task that is currently being executed
+    private var curJobData: JobDataImpl? = null
+    // Used to keep track of when the current task should end
+    private var curJobEndTime = 0L
+    // Tick work time options
+    private inline val options get() = optionsRoot.tickWorktime
+
+    override fun submit(job: TimeLimitedTask): JobData {
+        val jobData = JobDataImpl(job)
+        jobs.addFirst(jobData)
+        if (task == null) task = plugin.server.scheduler.runTaskTimer(plugin, ::tickJobs, 0, options.tickInterval.toLong())
+        return jobData
+    }
+
+    override suspend fun markSuspensionPoint() {
+        if (System.currentTimeMillis() >= curJobEndTime)
+            suspendCoroutineUninterceptedOrReturn(::scheduleContinuation)
+    }
+
+    override fun setProgress(progress: Double) {
+        curJobData!!.progress = progress
+    }
+
+    private fun tickJobs() {
+        if (jobs.isEmpty()) return
+        val tickStartTime = System.currentTimeMillis()
+        val jobs = this.jobs; this.jobs = LinkedList()
+
+        var count = jobs.size
+
+        while (!jobs.isEmpty()) {
+            val job = jobs.poll()
+            val time = System.currentTimeMillis()
+            val timeElapsed = time - tickStartTime
+            val timeLeft = options.workTime - timeElapsed
+
+            if (timeLeft <= 0) {
+                this.jobs.addAll(0, jobs)
+                return
+            }
+
+            val timePerJob = (timeLeft + count - 1) / count
+            tickJob(job, time + timePerJob)
+            count--
+        }
+
+        if (jobs.isEmpty() && this.jobs.isEmpty()) {
+            task?.cancel()
+            task = null
+        }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private fun tickJob(job: JobDataImpl, endTime: Long) {
+        curJobData = job
+        curJobEndTime = endTime
+        try {
+            val next = job.next
+            if (next == null) startJob(job)
+            else next.resume(Unit)
+        }
+        finally {
+            curJobData = null
+            curJobEndTime = 0L
+        }
+    }
+
+    private fun startJob(job: JobDataImpl) {
+        job.job = launch(context = dispatcher, start = CoroutineStart.UNDISPATCHED) { job.task(this@TickWorktimeLimiter) }
+    }
+
+    private fun scheduleContinuation(continuation: Continuation<Unit>): Any? {
+        curJobData!!.next = continuation
+        jobs.addLast(curJobData)
+        return COROUTINE_SUSPENDED
+    }
+
+}
+
+data class TickWorktimeOptions(var workTime: Int, var tickInterval: Int)
+
+
+/**
+ * While the implementation of [kotlin.coroutines.experimental.intrinsics.intercepted] is intrinsic, it should look something like this
+ * We don't care for intercepting the coroutine as we want it to resume immediately when we call resume().
+ * Thus, above, we use an unintercepted suspension. It's not necessary as the dispatcher (or interceptor) also calls it synchronously, but whatever.
+ */
+private fun <T> Continuation<T>.interceptedImpl(): Continuation<T> {
+    return context[ContinuationInterceptor]?.interceptContinuation(this) ?: this
+}
\ No newline at end of file
diff --git a/src/main/kotlin/io/dico/parcels2/command/CommandsGeneral.kt b/src/main/kotlin/io/dico/parcels2/command/CommandsGeneral.kt
index 7308a00..715e957 100644
--- a/src/main/kotlin/io/dico/parcels2/command/CommandsGeneral.kt
+++ b/src/main/kotlin/io/dico/parcels2/command/CommandsGeneral.kt
@@ -1,15 +1,18 @@
 package io.dico.parcels2.command
 
+import io.dico.dicore.command.ExecutionContext
 import io.dico.dicore.command.annotation.Cmd
 import io.dico.dicore.command.annotation.Desc
 import io.dico.dicore.command.annotation.RequireParameters
 import io.dico.parcels2.ParcelOwner
 import io.dico.parcels2.ParcelsPlugin
+import io.dico.parcels2.blockvisitor.JobUpdateListener
 import io.dico.parcels2.command.NamedParcelDefaultValue.FIRST_OWNED
 import io.dico.parcels2.storage.getParcelBySerializedValue
 import io.dico.parcels2.util.hasAdminManage
 import io.dico.parcels2.util.hasParcelHomeOthers
 import io.dico.parcels2.util.uuid
+import kotlinx.coroutines.experimental.Job
 import org.bukkit.entity.Player
 
 //@Suppress("unused")
@@ -77,5 +80,13 @@ class CommandsGeneral(plugin: ParcelsPlugin) : AbstractParcelCommands(plugin) {
         return "Enjoy your new parcel!"
     }
 
+    @Cmd("clear")
+    @ParcelRequire(owner = true)
+    fun ParcelScope.cmdClear(player: Player, context: ExecutionContext) {
+        val onProgressUpdate: JobUpdateListener = { progress -> context.sendMessage("[Clearing] Progress: %.06f%%".format(progress * 100)) }
+        world.generator.clearParcel(parcel)
+            .onProgressUpdate(1000, 1500, onProgressUpdate)
+            .onCompleted(onProgressUpdate)
+    }
 
 }
\ No newline at end of file
diff --git a/src/main/kotlin/io/dico/parcels2/util/MaterialExtensions.kt b/src/main/kotlin/io/dico/parcels2/util/MaterialExtensions.kt
index 5cfcb47..f38f687 100644
--- a/src/main/kotlin/io/dico/parcels2/util/MaterialExtensions.kt
+++ b/src/main/kotlin/io/dico/parcels2/util/MaterialExtensions.kt
@@ -5,30 +5,9 @@ import org.bukkit.Material.*
 
 /* 
 colors:
-WHITE_$,
-ORANGE_$,
-MAGENTA_$,
-LIGHT_BLUE_$,
-YELLOW_$,
-LIME_$,
-PINK_$,
-GRAY_$,
-LIGHT_GRAY_$,
-CYAN_$,
-PURPLE_$,
-BLUE_$,
-BROWN_$,
-GREEN_$,
-RED_$,
-BLACK_$,
-
+WHITE_$, ORANGE_$, MAGENTA_$, LIGHT_BLUE_$, YELLOW_$, LIME_$, PINK_$, GRAY_$, LIGHT_GRAY_$, CYAN_$, PURPLE_$, BLUE_$, BROWN_$, GREEN_$, RED_$, BLACK_$, 
 wood:
-OAK_$,
-BIRCH_$,
-SPRUCE_$,
-JUNGLE_$,
-ACACIA_$,
-DARK_OAK_$,
+OAK_$, BIRCH_$, SPRUCE_$, JUNGLE_$, ACACIA_$, DARK_OAK_$,
  */
 
 val Material.isBed get() = when(this) {
diff --git a/src/main/kotlin/io/dico/parcels2/util/Region.kt b/src/main/kotlin/io/dico/parcels2/util/Region.kt
index 8cc98df..5717906 100644
--- a/src/main/kotlin/io/dico/parcels2/util/Region.kt
+++ b/src/main/kotlin/io/dico/parcels2/util/Region.kt
@@ -1,3 +1,5 @@
 package io.dico.parcels2.util
 
-data class Region(val origin: Vec3i, val size: Vec3i)
\ No newline at end of file
+data class Region(val origin: Vec3i, val size: Vec3i) {
+    val blockCount: Int get() = size.x * size.y * size.z
+}
\ No newline at end of file
diff --git a/src/main/kotlin/io/dico/parcels2/util/Vec3i.kt b/src/main/kotlin/io/dico/parcels2/util/Vec3i.kt
index d400fac..a4655d0 100644
--- a/src/main/kotlin/io/dico/parcels2/util/Vec3i.kt
+++ b/src/main/kotlin/io/dico/parcels2/util/Vec3i.kt
@@ -1,13 +1,19 @@
 package io.dico.parcels2.util
 
+import org.bukkit.World
+import org.bukkit.block.Block
+
 data class Vec3i(
     val x: Int,
     val y: Int,
     val z: Int
-)
+) {
+    operator fun plus(o: Vec3i) = Vec3i(x + o.x, y + o.y, z + o.z)
+    infix fun addX(o: Int) = Vec3i(x + o, y, z)
+    infix fun addY(o: Int) = Vec3i(x, y + o, z)
+    infix fun addZ(o: Int) = Vec3i(x, y, z + o)
+    fun add(ox: Int, oy: Int, oz: Int) = Vec3i(x + ox, y + oy, z + oz)
+}
 
-data class MutableVec3i(
-    var x: Int,
-    var y: Int,
-    var z: Int
-)
\ No newline at end of file
+@Suppress("NOTHING_TO_INLINE")
+inline operator fun World.get(vec: Vec3i): Block = getBlockAt(vec.x, vec.y, vec.z)
\ No newline at end of file