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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.lib.skyframe;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.google.common.collect.Interner;
import com.google.devtools.build.lib.concurrent.BlazeInterners;
import com.google.devtools.build.lib.packages.Package.ConfigSettingVisibilityPolicy;
import com.google.devtools.build.lib.packages.RuleVisibility;
import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import com.google.devtools.build.skyframe.AbstractSkyKey;
import com.google.devtools.build.skyframe.Injectable;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyFunctionName;
import com.google.devtools.build.skyframe.SkyValue;
import java.util.Map;
import java.util.UUID;
import javax.annotation.Nullable;
import net.starlark.java.eval.StarlarkSemantics;
/**
* A value that represents something computed outside of the skyframe framework. These values are
* "precomputed" from skyframe's perspective and so the graph needs to be prepopulated with them
* (e.g. via injection).
*/
@AutoCodec
public class PrecomputedValue implements SkyValue {
/**
* An externally-injected precomputed value. Exists so that modules can inject precomputed values
* into Skyframe's graph.
*
* @see com.google.devtools.build.lib.runtime.BlazeModule#getPrecomputedValues
*/
public static final class Injected {
private final Precomputed<?> precomputed;
private final Supplier<? extends Object> supplier;
private Injected(Precomputed<?> precomputed, Supplier<? extends Object> supplier) {
this.precomputed = precomputed;
this.supplier = supplier;
}
public void inject(Injectable injectable) {
injectable.inject(precomputed.key, new PrecomputedValue(supplier.get()));
}
@Override
public String toString() {
return precomputed + ": " + supplier.get();
}
}
public static <T> Injected injected(Precomputed<T> precomputed, Supplier<T> value) {
return new Injected(precomputed, value);
}
public static <T> Injected injected(Precomputed<T> precomputed, T value) {
return new Injected(precomputed, Suppliers.ofInstance(value));
}
public static final Precomputed<RuleVisibility> DEFAULT_VISIBILITY =
new Precomputed<>("default_visibility");
public static final Precomputed<ConfigSettingVisibilityPolicy> CONFIG_SETTING_VISIBILITY_POLICY =
new Precomputed<>("config_setting_visibility_policy");
public static final Precomputed<StarlarkSemantics> STARLARK_SEMANTICS =
new Precomputed<>("starlark_semantics");
static final Precomputed<UUID> BUILD_ID = new UnsharablePrecomputed<>("build_id");
public static final Precomputed<Map<String, String>> ACTION_ENV = new Precomputed<>("action_env");
public static final Precomputed<Map<String, String>> REPO_ENV = new Precomputed<>("repo_env");
public static final Precomputed<PathPackageLocator> PATH_PACKAGE_LOCATOR =
new Precomputed<>("path_package_locator");
public static final Precomputed<Boolean> REMOTE_EXECUTION_ENABLED =
new Precomputed<>("remote_execution_enabled");
private final Object value;
@AutoCodec.Instantiator
public PrecomputedValue(Object value) {
this.value = Preconditions.checkNotNull(value);
}
/**
* Returns the value of the variable.
*/
public Object get() {
return value;
}
@Override
public int hashCode() {
return value.hashCode();
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof PrecomputedValue)) {
return false;
}
PrecomputedValue other = (PrecomputedValue) obj;
return value.equals(other.value);
}
@Override
public String toString() {
return "<BuildVariable " + value + ">";
}
/**
* A helper object corresponding to a variable in Skyframe.
*
* <p>Instances do not have internal state.
*/
public static class Precomputed<T> {
protected final Key key;
public Precomputed(String key) {
this.key = Key.create(key);
}
@VisibleForTesting
public Key getKeyForTesting() {
return key;
}
/**
* Retrieves the value of this variable from Skyframe.
*
* <p>If the value was not set, an exception will be raised.
*/
@Nullable
@SuppressWarnings("unchecked")
public T get(SkyFunction.Environment env) throws InterruptedException {
PrecomputedValue value = (PrecomputedValue) env.getValue(key);
if (value == null) {
return null;
}
return (T) value.get();
}
/** Injects a new variable value. */
public void set(Injectable injectable, T value) {
injectable.inject(key, new PrecomputedValue(value));
}
}
private static class UnsharablePrecomputed<T> extends Precomputed<T> {
private UnsharablePrecomputed(String key) {
super(key);
}
/** Injects a new variable value. */
@Override
public void set(Injectable injectable, T value) {
injectable.inject(key, new UnshareablePrecomputedValue(value));
}
}
/** An unshareable version of {@link PrecomputedValue}. */
private static final class UnshareablePrecomputedValue extends PrecomputedValue {
private UnshareablePrecomputedValue(Object value) {
super(value);
}
@Override
public boolean dataIsShareable() {
return false;
}
}
/** {@link com.google.devtools.build.skyframe.SkyKey} for {@code PrecomputedValue}. */
@AutoCodec
public static class Key extends AbstractSkyKey<String> {
private static final Interner<Key> interner = BlazeInterners.newWeakInterner();
private Key(String arg) {
super(arg);
}
@AutoCodec.Instantiator
public static Key create(String arg) {
return interner.intern(new Key(arg));
}
@Override
public SkyFunctionName functionName() {
return SkyFunctions.PRECOMPUTED;
}
}
}