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// Copyright 2017 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.rules;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
import com.google.devtools.build.lib.cmdline.RepositoryName;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.packages.BuildFileContainsErrorsException;
import com.google.devtools.build.lib.packages.NoSuchPackageException;
import com.google.devtools.build.lib.packages.Package;
import com.google.devtools.build.lib.packages.Rule;
import com.google.devtools.build.lib.skyframe.PackageLookupValue;
import com.google.devtools.build.lib.skyframe.PackageValue;
import com.google.devtools.build.lib.skyframe.WorkspaceFileValue;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.util.Preconditions;
import com.google.devtools.build.lib.vfs.RootedPath;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyFunction.Environment;
import com.google.devtools.build.skyframe.SkyFunctionException;
import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
import com.google.devtools.build.skyframe.SkyKey;
import java.io.IOException;
import java.util.List;
import javax.annotation.Nullable;
/** Utility class to centralize looking up rules from the external package. */
public class ExternalPackageUtil {
/**
* Loads the external package and then calls the selector to find matching rules.
*
* @param env the environment to use for lookups
* @param returnFirst whether to return only the first rule found
* @param selector the function to call to load rules
*/
@Nullable
private static List<Rule> getRules(
Environment env, boolean returnFirst, Function<Package, Iterable<Rule>> selector)
throws ExternalPackageException, InterruptedException {
SkyKey packageLookupKey = PackageLookupValue.key(Label.EXTERNAL_PACKAGE_IDENTIFIER);
PackageLookupValue packageLookupValue = (PackageLookupValue) env.getValue(packageLookupKey);
if (packageLookupValue == null) {
return null;
}
RootedPath workspacePath = packageLookupValue.getRootedPath(Label.EXTERNAL_PACKAGE_IDENTIFIER);
List<Rule> rules = ImmutableList.of();
SkyKey workspaceKey = WorkspaceFileValue.key(workspacePath);
do {
WorkspaceFileValue value = (WorkspaceFileValue) env.getValue(workspaceKey);
if (value == null) {
return null;
}
Package externalPackage = value.getPackage();
if (externalPackage.containsErrors()) {
Event.replayEventsOn(env.getListener(), externalPackage.getEvents());
throw new ExternalPackageException(
new BuildFileContainsErrorsException(
Label.EXTERNAL_PACKAGE_IDENTIFIER, "Could not load //external package"),
Transience.PERSISTENT);
}
Iterable<Rule> results = selector.apply(externalPackage);
if (results != null) {
rules = ImmutableList.copyOf(results);
if (returnFirst && !rules.isEmpty()) {
return ImmutableList.of(Iterables.getFirst(results, null));
}
}
workspaceKey = value.next();
} while (workspaceKey != null);
return rules;
}
/** Uses a rule name to fetch the corresponding Rule from the external package. */
@Nullable
public static List<Rule> getRuleByRuleClass(final String ruleClassName, Environment env)
throws ExternalPackageException, InterruptedException {
List<Rule> rules =
getRules(
env,
false,
new Function<Package, Iterable<Rule>>() {
@Nullable
@Override
public Iterable<Rule> apply(Package externalPackage) {
return externalPackage.getRulesMatchingRuleClass(ruleClassName);
}
});
if (env.valuesMissing()) {
return null;
}
return ImmutableList.copyOf(rules);
}
/** Uses a rule name to fetch the corresponding Rule from the external package. */
@Nullable
public static Rule getRuleByName(final String ruleName, Environment env)
throws ExternalPackageException, InterruptedException {
List<Rule> rules =
getRules(
env,
true,
new Function<Package, Iterable<Rule>>() {
@Nullable
@Override
public Iterable<Rule> apply(Package externalPackage) {
Rule rule = externalPackage.getRule(ruleName);
if (rule == null) {
return null;
}
return ImmutableList.of(rule);
}
});
if (env.valuesMissing()) {
return null;
}
if (rules == null || rules.isEmpty()) {
throw new ExternalRuleNotFoundException(ruleName);
}
return Iterables.getFirst(rules, null);
}
@Nullable
public static Rule getRule(String ruleName, @Nullable String ruleClassName, Environment env)
throws ExternalPackageException, InterruptedException {
try {
return getRepository(RepositoryName.create("@" + ruleName), ruleClassName, env);
} catch (LabelSyntaxException e) {
throw new ExternalPackageException(
new IOException("Invalid rule name " + ruleName), Transience.PERSISTENT);
}
}
/**
* Uses a remote repository name to fetch the corresponding Rule describing how to get it. This
* should be called from {@link SkyFunction#compute} functions, which should return null if this
* returns null. If {@code ruleClassName} is set, the rule found must have a matching rule class
* name.
*/
@Nullable
public static Rule getRepository(
RepositoryName repositoryName, @Nullable String ruleClassName, Environment env)
throws ExternalPackageException, InterruptedException {
Rule rule = getRuleByName(repositoryName.strippedName(), env);
Preconditions.checkState(
rule == null || ruleClassName == null || rule.getRuleClass().equals(ruleClassName),
"Got %s, was expecting a %s",
rule,
ruleClassName);
return rule;
}
/**
* Loads the external package and then returns the registered toolchain labels.
*
* @param env the environment to use for lookups
*/
@Nullable
public static List<Label> getRegisteredToolchainLabels(Environment env)
throws ExternalPackageException, InterruptedException {
PackageValue externalPackageValue =
(PackageValue) env.getValue(PackageValue.key(Label.EXTERNAL_PACKAGE_IDENTIFIER));
if (externalPackageValue == null) {
return null;
}
Package externalPackage = externalPackageValue.getPackage();
return externalPackage.getRegisteredToolchainLabels();
}
/** Exception thrown when something goes wrong accessing a rule. */
public static class ExternalPackageException extends SkyFunctionException {
public ExternalPackageException(NoSuchPackageException cause, Transience transience) {
super(cause, transience);
}
/** Error reading or writing to the filesystem. */
public ExternalPackageException(IOException cause, Transience transience) {
super(cause, transience);
}
/** For errors in WORKSPACE file rules (e.g., malformed paths or URLs). */
public ExternalPackageException(EvalException cause, Transience transience) {
super(cause, transience);
}
}
/** Exception thrown when a rule cannot be found. */
public static final class ExternalRuleNotFoundException extends ExternalPackageException {
public ExternalRuleNotFoundException(String ruleName) {
super(
new BuildFileContainsErrorsException(
Label.EXTERNAL_PACKAGE_IDENTIFIER,
"The rule named '" + ruleName + "' could not be resolved"),
Transience.PERSISTENT);
}
}
}
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