GenerationChunkHolder.java

net.minecraft.server.level.GenerationChunkHolder

信息

• 全限定名：net.minecraft.server.level.GenerationChunkHolder
• 类型：public abstract class
• 包：net.minecraft.server.level
• 源码路径：src/main/java/net/minecraft/server/level/GenerationChunkHolder.java
• 起始行号：L23
• 职责：

  TODO

字段/常量

• CHUNK_STATUSES

  • 类型: List<ChunkStatus>
  • 修饰符: private static final
  • 源码定位: L24
  • 说明:

    TODO

• NOT_DONE_YET

  • 类型: ChunkResult<ChunkAccess>
  • 修饰符: private static final
  • 源码定位: L25
  • 说明:

    TODO

• UNLOADED_CHUNK

  • 类型: ChunkResult<ChunkAccess>
  • 修饰符: public static final
  • 源码定位: L26
  • 说明:

    TODO

• UNLOADED_CHUNK_FUTURE

  • 类型: CompletableFuture<ChunkResult<ChunkAccess>>
  • 修饰符: public static final
  • 源码定位: L27
  • 说明:

    TODO

• pos

  • 类型: ChunkPos
  • 修饰符: protected final
  • 源码定位: L28
  • 说明:

    TODO

• highestAllowedStatus

  • 类型: ChunkStatus
  • 修饰符: private volatile
  • 源码定位: L29
  • 说明:

    TODO

• startedWork

  • 类型: AtomicReference<ChunkStatus>
  • 修饰符: private final
  • 源码定位: L30
  • 说明:

    TODO

• futures

  • 类型: AtomicReferenceArray<CompletableFuture<ChunkResult<ChunkAccess>>>
  • 修饰符: private final
  • 源码定位: L31
  • 说明:

    TODO

• task

  • 类型: AtomicReference<ChunkGenerationTask>
  • 修饰符: private final
  • 源码定位: L32
  • 说明:

    TODO

• generationRefCount

  • 类型: AtomicInteger
  • 修饰符: private final
  • 源码定位: L33
  • 说明:

    TODO

• generationSaveSyncFuture

  • 类型: CompletableFuture<Void>
  • 修饰符: private volatile
  • 源码定位: L34
  • 说明:

    TODO

内部类/嵌套类型

• 无

构造器

public GenerationChunkHolder(ChunkPos pos) @ L36

• 构造器名：GenerationChunkHolder
• 源码定位：L36
• 修饰符：public

参数:

• pos: ChunkPos

说明:

TODO

方法

下面的方法块按源码顺序生成。

public CompletableFuture<ChunkResult<ChunkAccess>> scheduleChunkGenerationTask(ChunkStatus status, ChunkMap scheduler) @ L43

• 方法名：scheduleChunkGenerationTask
• 源码定位：L43
• 返回类型：CompletableFuture<ChunkResult>
• 修饰符：public

参数:

• status: ChunkStatus
• scheduler: ChunkMap

说明:

TODO

CompletableFuture<ChunkResult<ChunkAccess>> applyStep(ChunkStep step, GeneratingChunkMap chunkMap, StaticCache2D<GenerationChunkHolder> cache) @ L61

• 方法名：applyStep
• 源码定位：L61
• 返回类型：CompletableFuture<ChunkResult>
• 修饰符：package-private

参数:

• step: ChunkStep
• chunkMap: GeneratingChunkMap
• cache: StaticCache2D

说明:

TODO

protected void updateHighestAllowedStatus(ChunkMap scheduler) @ L78

• 方法名：updateHighestAllowedStatus
• 源码定位：L78
• 返回类型：void
• 修饰符：protected

参数:

• scheduler: ChunkMap

说明:

TODO

public void replaceProtoChunk(ImposterProtoChunk chunk) @ L91

• 方法名：replaceProtoChunk
• 源码定位：L91
• 返回类型：void
• 修饰符：public

参数:

• chunk: ImposterProtoChunk

说明:

TODO

void removeTask(ChunkGenerationTask task) @ L108

• 方法名：removeTask
• 源码定位：L108
• 返回类型：void
• 修饰符：package-private

参数:

• task: ChunkGenerationTask

说明:

TODO

private void rescheduleChunkTask(ChunkMap scheduler, ChunkStatus status) @ L112

• 方法名：rescheduleChunkTask
• 源码定位：L112
• 返回类型：void
• 修饰符：private

参数:

• scheduler: ChunkMap
• status: ChunkStatus

说明:

TODO

private CompletableFuture<ChunkResult<ChunkAccess>> getOrCreateFuture(ChunkStatus status) @ L126

• 方法名：getOrCreateFuture
• 源码定位：L126
• 返回类型：CompletableFuture<ChunkResult>
• 修饰符：private

参数:

• status: ChunkStatus

说明:

TODO

private void failAndClearPendingFuturesBetween(ChunkStatus fromExclusive, ChunkStatus toInclusive) @ L150

• 方法名：failAndClearPendingFuturesBetween
• 源码定位：L150
• 返回类型：void
• 修饰符：private

参数:

• fromExclusive: ChunkStatus
• toInclusive: ChunkStatus

说明:

TODO

private void failAndClearPendingFuture(int index, CompletableFuture<ChunkResult<ChunkAccess>> previous) @ L162

• 方法名：failAndClearPendingFuture
• 源码定位：L162
• 返回类型：void
• 修饰符：private

参数:

• index: int
• previous: CompletableFuture<ChunkResult>

说明:

TODO

private void completeFuture(ChunkStatus status, ChunkAccess chunk) @ L168

• 方法名：completeFuture
• 源码定位：L168
• 返回类型：void
• 修饰符：private

参数:

• status: ChunkStatus
• chunk: ChunkAccess

说明:

TODO

private ChunkStatus findHighestStatusWithPendingFuture(ChunkStatus newStatus) @ L192

• 方法名：findHighestStatusWithPendingFuture
• 源码定位：L192
• 返回类型：ChunkStatus
• 修饰符：private

参数:

• newStatus: ChunkStatus

说明:

TODO

private boolean acquireStatusBump(ChunkStatus status) @ L215

• 方法名：acquireStatusBump
• 源码定位：L215
• 返回类型：boolean
• 修饰符：private

参数:

• status: ChunkStatus

说明:

TODO

private boolean isStatusDisallowed(ChunkStatus status) @ L227

• 方法名：isStatusDisallowed
• 源码定位：L227
• 返回类型：boolean
• 修饰符：private

参数:

• status: ChunkStatus

说明:

TODO

protected abstract void addSaveDependency(CompletableFuture<?> sync) @ L232

• 方法名：addSaveDependency
• 源码定位：L232
• 返回类型：void
• 修饰符：protected abstract

参数:

• sync: CompletableFuture<?>

说明:

TODO

public void increaseGenerationRefCount() @ L234

• 方法名：increaseGenerationRefCount
• 源码定位：L234
• 返回类型：void
• 修饰符：public

参数:

• 无

说明:

TODO

public void decreaseGenerationRefCount() @ L241

• 方法名：decreaseGenerationRefCount
• 源码定位：L241
• 返回类型：void
• 修饰符：public

参数:

• 无

说明:

TODO

public ChunkAccess getChunkIfPresentUnchecked(ChunkStatus status) @ L253

• 方法名：getChunkIfPresentUnchecked
• 源码定位：L253
• 返回类型：ChunkAccess
• 修饰符：public

参数:

• status: ChunkStatus

说明:

TODO

public ChunkAccess getChunkIfPresent(ChunkStatus status) @ L258

• 方法名：getChunkIfPresent
• 源码定位：L258
• 返回类型：ChunkAccess
• 修饰符：public

参数:

• status: ChunkStatus

说明:

TODO

public ChunkAccess getLatestChunk() @ L262

• 方法名：getLatestChunk
• 源码定位：L262
• 返回类型：ChunkAccess
• 修饰符：public

参数:

• 无

说明:

TODO

public ChunkStatus getPersistedStatus() @ L272

• 方法名：getPersistedStatus
• 源码定位：L272
• 返回类型：ChunkStatus
• 修饰符：public

参数:

• 无

说明:

TODO

public ChunkPos getPos() @ L278

• 方法名：getPos
• 源码定位：L278
• 返回类型：ChunkPos
• 修饰符：public

参数:

• 无

说明:

TODO

public FullChunkStatus getFullStatus() @ L282

• 方法名：getFullStatus
• 源码定位：L282
• 返回类型：FullChunkStatus
• 修饰符：public

参数:

• 无

说明:

TODO

public abstract int getTicketLevel() @ L286

• 方法名：getTicketLevel
• 源码定位：L286
• 返回类型：int
• 修饰符：public abstract

参数:

• 无

说明:

TODO

public abstract int getQueueLevel() @ L288

• 方法名：getQueueLevel
• 源码定位：L288
• 返回类型：int
• 修饰符：public abstract

参数:

• 无

说明:

TODO

public List<Pair<ChunkStatus,CompletableFuture<ChunkResult<ChunkAccess>>>> getAllFutures() @ L290

• 方法名：getAllFutures
• 源码定位：L290
• 返回类型：List<Pair<ChunkStatus,CompletableFuture<ChunkResult>>>
• 修饰符：public

参数:

• 无

说明:

TODO

public ChunkStatus getLatestStatus() @ L301

• 方法名：getLatestStatus
• 源码定位：L301
• 返回类型：ChunkStatus
• 修饰符：public

参数:

• 无

说明:

TODO

代码

public abstract class GenerationChunkHolder {
    private static final List<ChunkStatus> CHUNK_STATUSES = ChunkStatus.getStatusList();
    private static final ChunkResult<ChunkAccess> NOT_DONE_YET = ChunkResult.error("Not done yet");
    public static final ChunkResult<ChunkAccess> UNLOADED_CHUNK = ChunkResult.error("Unloaded chunk");
    public static final CompletableFuture<ChunkResult<ChunkAccess>> UNLOADED_CHUNK_FUTURE = CompletableFuture.completedFuture(UNLOADED_CHUNK);
    protected final ChunkPos pos;
    private volatile @Nullable ChunkStatus highestAllowedStatus;
    private final AtomicReference<@Nullable ChunkStatus> startedWork = new AtomicReference<>();
    private final AtomicReferenceArray<@Nullable CompletableFuture<ChunkResult<ChunkAccess>>> futures = new AtomicReferenceArray<>(CHUNK_STATUSES.size());
    private final AtomicReference<@Nullable ChunkGenerationTask> task = new AtomicReference<>();
    private final AtomicInteger generationRefCount = new AtomicInteger();
    private volatile CompletableFuture<Void> generationSaveSyncFuture = CompletableFuture.completedFuture(null);
 
    public GenerationChunkHolder(ChunkPos pos) {
        this.pos = pos;
        if (!pos.isValid()) {
            throw new IllegalStateException("Trying to create chunk out of reasonable bounds: " + pos);
        }
    }
 
    public CompletableFuture<ChunkResult<ChunkAccess>> scheduleChunkGenerationTask(ChunkStatus status, ChunkMap scheduler) {
        if (this.isStatusDisallowed(status)) {
            return UNLOADED_CHUNK_FUTURE;
        } else {
            CompletableFuture<ChunkResult<ChunkAccess>> future = this.getOrCreateFuture(status);
            if (future.isDone()) {
                return future;
            } else {
                ChunkGenerationTask task = this.task.get();
                if (task == null || status.isAfter(task.targetStatus)) {
                    this.rescheduleChunkTask(scheduler, status);
                }
 
                return future;
            }
        }
    }
 
    CompletableFuture<ChunkResult<ChunkAccess>> applyStep(ChunkStep step, GeneratingChunkMap chunkMap, StaticCache2D<GenerationChunkHolder> cache) {
        if (this.isStatusDisallowed(step.targetStatus())) {
            return UNLOADED_CHUNK_FUTURE;
        } else {
            return this.acquireStatusBump(step.targetStatus()) ? chunkMap.applyStep(this, step, cache).handle((chunk, exception) -> {
                if (exception != null) {
                    CrashReport report = CrashReport.forThrowable(exception, "Exception chunk generation/loading");
                    BlockableEventLoop.relayDelayCrash(report);
                } else {
                    this.completeFuture(step.targetStatus(), chunk);
                }
 
                return ChunkResult.of(chunk);
            }) : this.getOrCreateFuture(step.targetStatus());
        }
    }
 
    protected void updateHighestAllowedStatus(ChunkMap scheduler) {
        ChunkStatus oldStatus = this.highestAllowedStatus;
        ChunkStatus newStatus = ChunkLevel.generationStatus(this.getTicketLevel());
        this.highestAllowedStatus = newStatus;
        boolean statusDropped = oldStatus != null && (newStatus == null || newStatus.isBefore(oldStatus));
        if (statusDropped) {
            this.failAndClearPendingFuturesBetween(newStatus, oldStatus);
            if (this.task.get() != null) {
                this.rescheduleChunkTask(scheduler, this.findHighestStatusWithPendingFuture(newStatus));
            }
        }
    }
 
    public void replaceProtoChunk(ImposterProtoChunk chunk) {
        CompletableFuture<ChunkResult<ChunkAccess>> imposterFuture = CompletableFuture.completedFuture(ChunkResult.of(chunk));
 
        for (int i = 0; i < this.futures.length() - 1; i++) {
            CompletableFuture<ChunkResult<ChunkAccess>> future = this.futures.get(i);
            Objects.requireNonNull(future);
            ChunkAccess maybeProtoChunk = future.getNow(NOT_DONE_YET).orElse(null);
            if (!(maybeProtoChunk instanceof ProtoChunk)) {
                throw new IllegalStateException("Trying to replace a ProtoChunk, but found " + maybeProtoChunk);
            }
 
            if (!this.futures.compareAndSet(i, future, imposterFuture)) {
                throw new IllegalStateException("Future changed by other thread while trying to replace it");
            }
        }
    }
 
    void removeTask(ChunkGenerationTask task) {
        this.task.compareAndSet(task, null);
    }
 
    private void rescheduleChunkTask(ChunkMap scheduler, @Nullable ChunkStatus status) {
        ChunkGenerationTask newTask;
        if (status != null) {
            newTask = scheduler.scheduleGenerationTask(status, this.getPos());
        } else {
            newTask = null;
        }
 
        ChunkGenerationTask oldTask = this.task.getAndSet(newTask);
        if (oldTask != null) {
            oldTask.markForCancellation();
        }
    }
 
    private CompletableFuture<ChunkResult<ChunkAccess>> getOrCreateFuture(ChunkStatus status) {
        if (this.isStatusDisallowed(status)) {
            return UNLOADED_CHUNK_FUTURE;
        } else {
            int index = status.getIndex();
            CompletableFuture<ChunkResult<ChunkAccess>> future = this.futures.get(index);
 
            while (future == null) {
                CompletableFuture<ChunkResult<ChunkAccess>> newValue = new CompletableFuture<>();
                future = this.futures.compareAndExchange(index, null, newValue);
                if (future == null) {
                    if (this.isStatusDisallowed(status)) {
                        this.failAndClearPendingFuture(index, newValue);
                        return UNLOADED_CHUNK_FUTURE;
                    }
 
                    return newValue;
                }
            }
 
            return future;
        }
    }
 
    private void failAndClearPendingFuturesBetween(@Nullable ChunkStatus fromExclusive, ChunkStatus toInclusive) {
        int start = fromExclusive == null ? 0 : fromExclusive.getIndex() + 1;
        int end = toInclusive.getIndex();
 
        for (int i = start; i <= end; i++) {
            CompletableFuture<ChunkResult<ChunkAccess>> previous = this.futures.get(i);
            if (previous != null) {
                this.failAndClearPendingFuture(i, previous);
            }
        }
    }
 
    private void failAndClearPendingFuture(int index, CompletableFuture<ChunkResult<ChunkAccess>> previous) {
        if (previous.complete(UNLOADED_CHUNK) && !this.futures.compareAndSet(index, previous, null)) {
            throw new IllegalStateException("Nothing else should replace the future here");
        }
    }
 
    private void completeFuture(ChunkStatus status, ChunkAccess chunk) {
        ChunkResult<ChunkAccess> result = ChunkResult.of(chunk);
        int index = status.getIndex();
 
        while (true) {
            CompletableFuture<ChunkResult<ChunkAccess>> future = this.futures.get(index);
            if (future == null) {
                if (this.futures.compareAndSet(index, null, CompletableFuture.completedFuture(result))) {
                    return;
                }
            } else {
                if (future.complete(result)) {
                    return;
                }
 
                if (future.getNow(NOT_DONE_YET).isSuccess()) {
                    throw new IllegalStateException("Trying to complete a future but found it to be completed successfully already");
                }
 
                Thread.yield();
            }
        }
    }
 
    private @Nullable ChunkStatus findHighestStatusWithPendingFuture(@Nullable ChunkStatus newStatus) {
        if (newStatus == null) {
            return null;
        } else {
            ChunkStatus highestStatus = newStatus;
 
            for (ChunkStatus alreadyStarted = this.startedWork.get();
                alreadyStarted == null || highestStatus.isAfter(alreadyStarted);
                highestStatus = highestStatus.getParent()
            ) {
                if (this.futures.get(highestStatus.getIndex()) != null) {
                    return highestStatus;
                }
 
                if (highestStatus == ChunkStatus.EMPTY) {
                    break;
                }
            }
 
            return null;
        }
    }
 
    private boolean acquireStatusBump(ChunkStatus status) {
        ChunkStatus parent = status == ChunkStatus.EMPTY ? null : status.getParent();
        ChunkStatus previousStarted = this.startedWork.compareAndExchange(parent, status);
        if (previousStarted == parent) {
            return true;
        } else if (previousStarted != null && !status.isAfter(previousStarted)) {
            return false;
        } else {
            throw new IllegalStateException("Unexpected last startedWork status: " + previousStarted + " while trying to start: " + status);
        }
    }
 
    private boolean isStatusDisallowed(ChunkStatus status) {
        ChunkStatus highestAllowedStatus = this.highestAllowedStatus;
        return highestAllowedStatus == null || status.isAfter(highestAllowedStatus);
    }
 
    protected abstract void addSaveDependency(final CompletableFuture<?> sync);
 
    public void increaseGenerationRefCount() {
        if (this.generationRefCount.getAndIncrement() == 0) {
            this.generationSaveSyncFuture = new CompletableFuture<>();
            this.addSaveDependency(this.generationSaveSyncFuture);
        }
    }
 
    public void decreaseGenerationRefCount() {
        CompletableFuture<Void> future = this.generationSaveSyncFuture;
        int newValue = this.generationRefCount.decrementAndGet();
        if (newValue == 0) {
            future.complete(null);
        }
 
        if (newValue < 0) {
            throw new IllegalStateException("More releases than claims. Count: " + newValue);
        }
    }
 
    public @Nullable ChunkAccess getChunkIfPresentUnchecked(ChunkStatus status) {
        CompletableFuture<ChunkResult<ChunkAccess>> future = this.futures.get(status.getIndex());
        return future == null ? null : future.getNow(NOT_DONE_YET).orElse(null);
    }
 
    public @Nullable ChunkAccess getChunkIfPresent(ChunkStatus status) {
        return this.isStatusDisallowed(status) ? null : this.getChunkIfPresentUnchecked(status);
    }
 
    public @Nullable ChunkAccess getLatestChunk() {
        ChunkStatus status = this.startedWork.get();
        if (status == null) {
            return null;
        } else {
            ChunkAccess chunk = this.getChunkIfPresentUnchecked(status);
            return chunk != null ? chunk : this.getChunkIfPresentUnchecked(status.getParent());
        }
    }
 
    public @Nullable ChunkStatus getPersistedStatus() {
        CompletableFuture<ChunkResult<ChunkAccess>> future = this.futures.get(ChunkStatus.EMPTY.getIndex());
        ChunkAccess chunkAccess = future == null ? null : future.getNow(NOT_DONE_YET).orElse(null);
        return chunkAccess == null ? null : chunkAccess.getPersistedStatus();
    }
 
    public ChunkPos getPos() {
        return this.pos;
    }
 
    public FullChunkStatus getFullStatus() {
        return ChunkLevel.fullStatus(this.getTicketLevel());
    }
 
    public abstract int getTicketLevel();
 
    public abstract int getQueueLevel();
 
    @VisibleForDebug
    public List<Pair<ChunkStatus, @Nullable CompletableFuture<ChunkResult<ChunkAccess>>>> getAllFutures() {
        List<Pair<ChunkStatus, CompletableFuture<ChunkResult<ChunkAccess>>>> result = new ArrayList<>();
 
        for (int i = 0; i < CHUNK_STATUSES.size(); i++) {
            result.add(Pair.of(CHUNK_STATUSES.get(i), this.futures.get(i)));
        }
 
        return result;
    }
 
    @VisibleForDebug
    public @Nullable ChunkStatus getLatestStatus() {
        ChunkStatus status = this.startedWork.get();
        if (status == null) {
            return null;
        } else {
            ChunkAccess chunk = this.getChunkIfPresentUnchecked(status);
            return chunk != null ? status : status.getParent();
        }
    }
}

引用的其他类

• CrashReport

  • 引用位置: 方法调用
  • 关联成员: CrashReport.forThrowable()

• ChunkGenerationTask

  • 引用位置: 参数/字段

• ChunkLevel

  • 引用位置: 方法调用
  • 关联成员: ChunkLevel.fullStatus(), ChunkLevel.generationStatus()

• ChunkMap

  • 引用位置: 参数

• ChunkResult

  • 引用位置: 参数/字段/方法调用/返回值
  • 关联成员: ChunkResult.error(), ChunkResult.of()

• FullChunkStatus

  • 引用位置: 返回值

• GeneratingChunkMap

  • 引用位置: 参数

• StaticCache2D

  • 引用位置: 参数

• BlockableEventLoop

  • 引用位置: 方法调用
  • 关联成员: BlockableEventLoop.relayDelayCrash()

• ChunkPos

  • 引用位置: 参数/字段/返回值

• ChunkAccess

  • 引用位置: 参数/字段/返回值

• ImposterProtoChunk

  • 引用位置: 参数

• ChunkStatus

  • 引用位置: 参数/字段/方法调用/返回值
  • 关联成员: ChunkStatus.getStatusList()

• ChunkStep

  • 引用位置: 参数