// Copyright 2015 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.ThreadSafe; import com.google.devtools.build.lib.util.Preconditions; import javax.annotation.Nullable; /** * A node in the graph without the means to access its value. All operations on this class are * thread-safe. Note, however, the warning on the return value of {@link #markDirty}. * *
This interface is public only for the benefit of alternative graph implementations outside of * the package. */ public interface ThinNodeEntry { /** Returns whether the entry has been built and is finished evaluating. */ @ThreadSafe boolean isDone(); /** * Returns an immutable iterable of the direct deps of this node. This method may only be called * after the evaluation of this node is complete. * *
This method is not very efficient, but is only be called in limited circumstances --
* when the node is about to be deleted, or when the node is expected to have no direct deps (in
* which case the overhead is not so bad). It should not be called repeatedly for the same node,
* since each call takes time proportional to the number of direct deps of the node.
*/
@ThreadSafe
Iterable May only be called if this entry is not done (i.e. {@link #isDone} is false) and
* {@param reverseDep} is present in {@link #getReverseDeps}
*/
@ThreadSafe
void removeInProgressReverseDep(SkyKey reverseDep);
/**
* Returns a copy of the set of reverse dependencies. Note that this introduces a potential
* check-then-act race; {@link #removeReverseDep} may fail for a key that is returned here.
*/
@ThreadSafe
Iterable {@code markDirty(b)} must not be called on an undone node if {@code isChanged() == b}.
* It is the caller's responsibility to ensure that this does not happen. Calling
* {@code markDirty(false)} when {@code isChanged() == true} has no effect. The idea here is that
* the caller will only ever want to call {@code markDirty()} a second time if a transition from a
* dirty-unchanged state to a dirty-changed state is required.
*
* @return A {@link ThinNodeEntry.MarkedDirtyResult} if the node was previously clean, and
* {@code null} if it was already dirty. If it was already dirty, the caller should abort its
* handling of this node, since another thread is already dealing with it. Note the warning on
* {@link ThinNodeEntry.MarkedDirtyResult} regarding the collection it provides.
*/
@Nullable
@ThreadSafe
MarkedDirtyResult markDirty(boolean isChanged);
/**
* Returned by {@link #markDirty} if that call changed the node from clean to dirty. Contains an
* iterable of the node's reverse deps for efficiency, because the single use case for {@link
* #markDirty} is during invalidation, and if such an invalidation call wins, the invalidator
* must immediately afterwards schedule the invalidation of the node's reverse deps.
*
* Warning: {@link #getReverseDepsUnsafe()} may return a live view of the reverse deps
* collection of the marked-dirty node. The consumer of this data must be careful only to
* iterate over and consume its values while that collection is guaranteed not to change. This
* is true during invalidation, because reverse deps don't change during invalidation.
*/
class MarkedDirtyResult {
private final Iterable