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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.skyframe;
import com.google.devtools.build.lib.concurrent.ThreadSafety;
import java.util.function.Supplier;
import javax.annotation.Nullable;
/** Receiver for various stages of the lifetime of a skyframe node evaluation. */
@ThreadSafety.ThreadSafe
public interface EvaluationProgressReceiver {
/** A no-op {@link EvaluationProgressReceiver}. */
EvaluationProgressReceiver NULL = new EvaluationProgressReceiver() {};
/** New state of the value entry after evaluation. */
enum EvaluationState {
/** The value was successfully re-evaluated. */
BUILT,
/** The value is clean or re-validated. */
CLEAN,
}
/** Whether or not evaluation of this node succeeded. */
enum EvaluationSuccessState {
SUCCESS(true),
FAILURE(false);
EvaluationSuccessState(boolean succeeded) {
this.succeeded = succeeded;
}
private final boolean succeeded;
public boolean succeeded() {
return succeeded;
}
public Supplier<EvaluationSuccessState> supplier() {
return () -> this;
}
}
/** New state of the value entry after invalidation. */
enum InvalidationState {
/** The value is dirty, although it might get re-validated again. */
DIRTY,
/** The value is dirty and got deleted, cannot get re-validated again. */
DELETED,
}
/** Overall state of the node while it is being evaluated. */
enum NodeState {
/** The node is undergoing a dirtiness check and may be re-validated. */
CHECK_DIRTY,
/** The node is prepping for evaluation. */
INITIALIZING_ENVIRONMENT,
/** The node is in compute(). */
COMPUTE,
/** The node is done evaluation and committing the result. */
COMMIT,
}
/**
* Notifies that the node for {@code key} has been invalidated.
*
* <p>{@code state} indicates the new state of the value.
*
* <p>May be called concurrently from multiple threads.
*
* <p>If {@code state} is {@link InvalidationState#DIRTY}, should only be called after a
* successful {@link ThinNodeEntry#markDirty} call: a call that returns a non-null value.
*/
default void invalidated(SkyKey skyKey, InvalidationState state) {}
/**
* Notifies that {@code skyKey} is about to get queued for evaluation.
*
* <p>Note that we don't guarantee that it actually got enqueued or will, only that if everything
* "goes well" (e.g. no interrupts happen) it will.
*
* <p>This guarantee is intentionally vague to encourage writing robust implementations.
*/
default void enqueueing(SkyKey skyKey) {}
/**
* Notifies that the node for {@code skyKey} is about to enter the given {@code nodeState}.
*
* <p>Notably, this includes {@link SkyFunction#compute} calls due to Skyframe restarts, but also
* dirtiness checking and node completion.
*/
default void stateStarting(SkyKey skyKey, NodeState nodeState) {}
/**
* Notifies that the node for {@code skyKey} is about to complete the given {@code nodeState}.
*
* <p>Always called symmetrically with {@link #stateStarting(SkyKey, NodeState)}}.
*/
default void stateEnding(SkyKey skyKey, NodeState nodeState) {}
/**
* Notifies that the node for {@code skyKey} has been evaluated, or found to not need
* re-evaluation.
*
* @param newValue The new value. Only available if just evaluated, i.e. on success *and* {@code
* state == EvaluationState.BUILT}
* @param newError The new error. Only available if just evaluated, i.e. on error *and* {@code
* state == EvaluationState.BUILT}
* @param evaluationSuccessState whether the node has a value or only an error, behind a {@link
* Supplier} for lazy retrieval. Available regardless of whether the node was just evaluated
* @param state {@code EvaluationState.BUILT} if the node needed to be evaluated and has a new
* value or error (i.e., {@code EvaluationState.BUILT} if and only if at least one of newValue
* and newError is non-null)
*/
default void evaluated(
SkyKey skyKey,
@Nullable SkyValue newValue,
@Nullable ErrorInfo newError,
Supplier<EvaluationSuccessState> evaluationSuccessState,
EvaluationState state) {}
}