Java tutorial
// 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.collect.ImmutableList; import com.google.common.collect.ImmutableSet; import com.google.devtools.build.lib.cmdline.Label; import com.google.devtools.build.lib.cmdline.LabelValidator; import com.google.devtools.build.lib.cmdline.PackageIdentifier; import com.google.devtools.build.lib.packages.BuildFileNotFoundException; import com.google.devtools.build.lib.packages.ErrorDeterminingRepositoryException; import com.google.devtools.build.lib.packages.NoSuchPackageException; import com.google.devtools.build.lib.pkgcache.PathPackageLocator; import com.google.devtools.build.lib.skyframe.PackageLookupValue.BuildFileName; import com.google.devtools.build.lib.syntax.EvalException; import com.google.devtools.build.lib.util.Preconditions; import com.google.devtools.build.lib.vfs.Path; import com.google.devtools.build.lib.vfs.PathFragment; import com.google.devtools.build.lib.vfs.RootedPath; import com.google.devtools.build.skyframe.SkyFunction; import com.google.devtools.build.skyframe.SkyFunctionException; import com.google.devtools.build.skyframe.SkyFunctionException.Transience; import com.google.devtools.build.skyframe.SkyKey; import com.google.devtools.build.skyframe.SkyValue; import java.io.IOException; import java.util.List; import java.util.concurrent.atomic.AtomicReference; import javax.annotation.Nullable; /** * SkyFunction for {@link PackageLookupValue}s. */ public class PackageLookupFunction implements SkyFunction { /** Lists possible ways to handle a package label which crosses into a new repository. */ public enum CrossRepositoryLabelViolationStrategy { /** Ignore the violation. */ IGNORE, /** Generate an error. */ ERROR; } private final AtomicReference<ImmutableSet<PackageIdentifier>> deletedPackages; private final CrossRepositoryLabelViolationStrategy crossRepositoryLabelViolationStrategy; private final List<BuildFileName> buildFilesByPriority; public PackageLookupFunction(AtomicReference<ImmutableSet<PackageIdentifier>> deletedPackages, CrossRepositoryLabelViolationStrategy crossRepositoryLabelViolationStrategy, List<BuildFileName> buildFilesByPriority) { this.deletedPackages = deletedPackages; this.crossRepositoryLabelViolationStrategy = crossRepositoryLabelViolationStrategy; this.buildFilesByPriority = buildFilesByPriority; } @Override public SkyValue compute(SkyKey skyKey, Environment env) throws PackageLookupFunctionException, InterruptedException { PathPackageLocator pkgLocator = PrecomputedValue.PATH_PACKAGE_LOCATOR.get(env); PackageIdentifier packageKey = (PackageIdentifier) skyKey.argument(); if (PackageFunction.isDefaultsPackage(packageKey)) { return PackageLookupValue.success(pkgLocator.getPathEntries().get(0), BuildFileName.BUILD); } if (!packageKey.getRepository().isMain()) { return computeExternalPackageLookupValue(skyKey, env, packageKey); } else if (packageKey.equals(Label.EXTERNAL_PACKAGE_IDENTIFIER)) { return computeWorkspacePackageLookupValue(env, pkgLocator.getPathEntries()); } String packageNameErrorMsg = LabelValidator .validatePackageName(packageKey.getPackageFragment().getPathString()); if (packageNameErrorMsg != null) { return PackageLookupValue .invalidPackageName("Invalid package name '" + packageKey + "': " + packageNameErrorMsg); } if (deletedPackages.get().contains(packageKey)) { return PackageLookupValue.DELETED_PACKAGE_VALUE; } BlacklistedPackagePrefixesValue blacklistedPatternsValue = (BlacklistedPackagePrefixesValue) env .getValue(BlacklistedPackagePrefixesValue.key()); if (blacklistedPatternsValue == null) { return null; } PathFragment buildFileFragment = packageKey.getPackageFragment(); for (PathFragment pattern : blacklistedPatternsValue.getPatterns()) { if (buildFileFragment.startsWith(pattern)) { return PackageLookupValue.DELETED_PACKAGE_VALUE; } } return findPackageByBuildFile(env, pkgLocator, packageKey); } @Nullable @Override public String extractTag(SkyKey skyKey) { return null; } @Nullable private PackageLookupValue findPackageByBuildFile(Environment env, PathPackageLocator pkgLocator, PackageIdentifier packageKey) throws PackageLookupFunctionException, InterruptedException { // TODO(bazel-team): The following is O(n^2) on the number of elements on the package path due // to having restart the SkyFunction after every new dependency. However, if we try to batch // the missing value keys, more dependencies than necessary will be declared. This wart can be // fixed once we have nicer continuation support [skyframe-loading] for (Path packagePathEntry : pkgLocator.getPathEntries()) { // This checks for the build file names in the correct precedence order. for (BuildFileName buildFileName : buildFilesByPriority) { PackageLookupValue result = getPackageLookupValue(env, packagePathEntry, packageKey, buildFileName); if (result == null) { return null; } if (result != PackageLookupValue.NO_BUILD_FILE_VALUE) { return result; } } } return PackageLookupValue.NO_BUILD_FILE_VALUE; } @Nullable private static FileValue getFileValue(RootedPath fileRootedPath, Environment env, PackageIdentifier packageIdentifier) throws PackageLookupFunctionException, InterruptedException { String basename = fileRootedPath.asPath().getBaseName(); SkyKey fileSkyKey = FileValue.key(fileRootedPath); FileValue fileValue = null; try { fileValue = (FileValue) env.getValueOrThrow(fileSkyKey, IOException.class, FileSymlinkException.class, InconsistentFilesystemException.class); } catch (IOException e) { // TODO(bazel-team): throw an IOException here and let PackageFunction wrap that into a // BuildFileNotFoundException. throw new PackageLookupFunctionException( new BuildFileNotFoundException(packageIdentifier, "IO errors while looking for " + basename + " file reading " + fileRootedPath.asPath() + ": " + e.getMessage(), e), Transience.PERSISTENT); } catch (FileSymlinkException e) { throw new PackageLookupFunctionException(new BuildFileNotFoundException(packageIdentifier, "Symlink cycle detected while trying to find " + basename + " file " + fileRootedPath.asPath()), Transience.PERSISTENT); } catch (InconsistentFilesystemException e) { // This error is not transient from the perspective of the PackageLookupFunction. throw new PackageLookupFunctionException(e, Transience.PERSISTENT); } return fileValue; } private PackageLookupValue getPackageLookupValue(Environment env, ImmutableList<Path> packagePathEntries, PackageIdentifier packageIdentifier, BuildFileName buildFileName) throws PackageLookupFunctionException, InterruptedException { // TODO(bazel-team): The following is O(n^2) on the number of elements on the package path due // to having restart the SkyFunction after every new dependency. However, if we try to batch // the missing value keys, more dependencies than necessary will be declared. This wart can be // fixed once we have nicer continuation support [skyframe-loading] for (Path packagePathEntry : packagePathEntries) { PackageLookupValue result = getPackageLookupValue(env, packagePathEntry, packageIdentifier, buildFileName); if (result == null) { return null; } if (result != PackageLookupValue.NO_BUILD_FILE_VALUE) { return result; } } return PackageLookupValue.NO_BUILD_FILE_VALUE; } private PackageLookupValue getPackageLookupValue(Environment env, Path packagePathEntry, PackageIdentifier packageIdentifier, BuildFileName buildFileName) throws InterruptedException, PackageLookupFunctionException { PathFragment buildFileFragment = buildFileName.getBuildFileFragment(packageIdentifier); RootedPath buildFileRootedPath = RootedPath.toRootedPath(packagePathEntry, buildFileFragment); if (crossRepositoryLabelViolationStrategy == CrossRepositoryLabelViolationStrategy.ERROR) { // Is this path part of a local repository? RootedPath currentPath = RootedPath.toRootedPath(packagePathEntry, buildFileFragment.getParentDirectory()); SkyKey repositoryLookupKey = LocalRepositoryLookupValue.key(currentPath); // TODO(jcater): Consider parallelizing these lookups. LocalRepositoryLookupValue localRepository; try { localRepository = (LocalRepositoryLookupValue) env.getValueOrThrow(repositoryLookupKey, ErrorDeterminingRepositoryException.class); if (localRepository == null) { return null; } } catch (ErrorDeterminingRepositoryException e) { // If the directory selected isn't part of a repository, that's an error. // TODO(katre): Improve the error message given here. throw new PackageLookupFunctionException(new BuildFileNotFoundException(packageIdentifier, "Unable to determine the local repository for directory " + currentPath.asPath().getPathString()), Transience.PERSISTENT); } if (localRepository.exists() && !localRepository.getRepository().equals(packageIdentifier.getRepository())) { // There is a repository mismatch, this is an error. // TODO(jcater): Work out the correct package name for this error message. return PackageLookupValue.invalidPackageName( "Package crosses into repository " + localRepository.getRepository().getName()); } // There's no local repository, keep going. } else { // Future-proof against adding future values to CrossRepositoryLabelViolationStrategy. Preconditions.checkState( crossRepositoryLabelViolationStrategy == CrossRepositoryLabelViolationStrategy.IGNORE, crossRepositoryLabelViolationStrategy); } // Check for the existence of the build file. FileValue fileValue = getFileValue(buildFileRootedPath, env, packageIdentifier); if (fileValue == null) { return null; } if (fileValue.isFile()) { return PackageLookupValue.success(buildFileRootedPath.getRoot(), buildFileName); } return PackageLookupValue.NO_BUILD_FILE_VALUE; } private PackageLookupValue computeWorkspacePackageLookupValue(Environment env, ImmutableList<Path> packagePathEntries) throws PackageLookupFunctionException, InterruptedException { PackageLookupValue result = getPackageLookupValue(env, packagePathEntries, Label.EXTERNAL_PACKAGE_IDENTIFIER, BuildFileName.WORKSPACE); if (result == null) { return null; } if (result.packageExists()) { return result; } // Fall back on the last package path entry if there were any and nothing else worked. // TODO(kchodorow): get rid of this, the semantics are wrong (successful package lookup should // mean the package exists). a bunch of tests need to be rewritten first though. if (packagePathEntries.isEmpty()) { return PackageLookupValue.NO_BUILD_FILE_VALUE; } Path lastPackagePath = packagePathEntries.get(packagePathEntries.size() - 1); FileValue lastPackagePackagePathFileValue = getFileValue( RootedPath.toRootedPath(lastPackagePath, PathFragment.EMPTY_FRAGMENT), env, Label.EXTERNAL_PACKAGE_IDENTIFIER); if (lastPackagePackagePathFileValue == null) { return null; } return lastPackagePackagePathFileValue.exists() ? PackageLookupValue.success(lastPackagePath, BuildFileName.WORKSPACE) : PackageLookupValue.NO_BUILD_FILE_VALUE; } /** * Gets a PackageLookupValue from a different Bazel repository. * * <p>To do this, it looks up the "external" package and finds a path mapping for the repository * name. */ private PackageLookupValue computeExternalPackageLookupValue(SkyKey skyKey, Environment env, PackageIdentifier packageIdentifier) throws PackageLookupFunctionException, InterruptedException { PackageIdentifier id = (PackageIdentifier) skyKey.argument(); SkyKey repositoryKey = RepositoryValue.key(id.getRepository()); RepositoryValue repositoryValue; try { repositoryValue = (RepositoryValue) env.getValueOrThrow(repositoryKey, NoSuchPackageException.class, IOException.class, EvalException.class); if (repositoryValue == null) { return null; } } catch (NoSuchPackageException | IOException | EvalException e) { throw new PackageLookupFunctionException(new BuildFileNotFoundException(id, e.getMessage()), Transience.PERSISTENT); } // This checks for the build file names in the correct precedence order. for (BuildFileName buildFileName : buildFilesByPriority) { PathFragment buildFileFragment = id.getPackageFragment().getChild(buildFileName.getFilename()); RootedPath buildFileRootedPath = RootedPath.toRootedPath(repositoryValue.getPath(), buildFileFragment); FileValue fileValue = getFileValue(buildFileRootedPath, env, packageIdentifier); if (fileValue == null) { return null; } if (fileValue.isFile()) { return PackageLookupValue.success(repositoryValue.getPath(), buildFileName); } } return PackageLookupValue.NO_BUILD_FILE_VALUE; } /** * Used to declare all the exception types that can be wrapped in the exception thrown by * {@link PackageLookupFunction#compute}. */ private static final class PackageLookupFunctionException extends SkyFunctionException { public PackageLookupFunctionException(BuildFileNotFoundException e, Transience transience) { super(e, transience); } public PackageLookupFunctionException(InconsistentFilesystemException e, Transience transience) { super(e, transience); } } }