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// Copyright 2014 Google Inc. 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.devtools.build.lib.cmdline.PackageIdentifier;
import com.google.devtools.build.lib.packages.RuleClassProvider;
import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
import com.google.devtools.build.lib.syntax.BuildFileAST;
import com.google.devtools.build.lib.syntax.Mutability;
import com.google.devtools.build.lib.syntax.Runtime;
import com.google.devtools.build.lib.syntax.ValidationEnvironment;
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;
/**
* A SkyFunction for {@link ASTFileLookupValue}s. Tries to locate a file and load it as a
* syntax tree and cache the resulting {@link BuildFileAST}. If the file doesn't exist
* the function doesn't fail but returns a specific NO_FILE ASTLookupValue.
*/
public class ASTFileLookupFunction implements SkyFunction {
private abstract static class FileLookupResult {
/** Returns whether the file lookup was successful. */
public abstract boolean lookupSuccessful();
/** If {@code lookupSuccessful()}, returns the {@link RootedPath} to the file. */
public abstract RootedPath rootedPath();
/** If {@code lookupSuccessful()}, returns the file's size, in bytes. */
public abstract long fileSize();
static FileLookupResult noFile() {
return UnsuccessfulFileResult.INSTANCE;
}
static FileLookupResult file(RootedPath rootedPath, long fileSize) {
return new SuccessfulFileResult(rootedPath, fileSize);
}
private static class SuccessfulFileResult extends FileLookupResult {
private final RootedPath rootedPath;
private final long fileSize;
private SuccessfulFileResult(RootedPath rootedPath, long fileSize) {
this.rootedPath = rootedPath;
this.fileSize = fileSize;
}
@Override
public boolean lookupSuccessful() {
return true;
}
@Override
public RootedPath rootedPath() {
return rootedPath;
}
@Override
public long fileSize() {
return fileSize;
}
}
private static class UnsuccessfulFileResult extends FileLookupResult {
private static final UnsuccessfulFileResult INSTANCE = new UnsuccessfulFileResult();
private UnsuccessfulFileResult() {
}
@Override
public boolean lookupSuccessful() {
return false;
}
@Override
public RootedPath rootedPath() {
throw new IllegalStateException("unsuccessful lookup");
}
@Override
public long fileSize() {
throw new IllegalStateException("unsuccessful lookup");
}
}
}
private final AtomicReference<PathPackageLocator> pkgLocator;
private final RuleClassProvider ruleClassProvider;
public ASTFileLookupFunction(AtomicReference<PathPackageLocator> pkgLocator,
RuleClassProvider ruleClassProvider) {
this.pkgLocator = pkgLocator;
this.ruleClassProvider = ruleClassProvider;
}
@Override
public SkyValue compute(SkyKey skyKey, Environment env) throws SkyFunctionException,
InterruptedException {
PackageIdentifier key = (PackageIdentifier) skyKey.argument();
PathFragment astFilePathFragment = key.getPackageFragment();
FileLookupResult lookupResult = getASTFile(env, key);
if (lookupResult == null) {
return null;
}
if (!lookupResult.lookupSuccessful()) {
return ASTFileLookupValue.noFile();
}
BuildFileAST ast = null;
Path path = lookupResult.rootedPath().asPath();
long fileSize = lookupResult.fileSize();
// Skylark files end with bzl.
boolean parseAsSkylark = astFilePathFragment.getPathString().endsWith(".bzl");
try {
if (parseAsSkylark) {
try (Mutability mutability = Mutability.create("validate")) {
ast = BuildFileAST.parseSkylarkFile(path, fileSize, env.getListener(),
new ValidationEnvironment(
ruleClassProvider.createSkylarkRuleClassEnvironment(
mutability,
env.getListener(),
// the two below don't matter for extracting the ValidationEnvironment:
/*astFileContentHashCode=*/null,
/*importMap=*/null)
.setupDynamic(Runtime.PKG_NAME, Runtime.NONE)));
}
} else {
ast = BuildFileAST.parseBuildFile(path, fileSize, env.getListener(), false);
}
} catch (IOException e) {
throw new ASTLookupFunctionException(new ErrorReadingSkylarkExtensionException(
e.getMessage()), Transience.TRANSIENT);
}
return ASTFileLookupValue.withFile(ast);
}
private FileLookupResult getASTFile(Environment env, PackageIdentifier key)
throws ASTLookupFunctionException {
List<Path> candidateRoots;
if (!key.getRepository().isDefault()) {
RepositoryValue repository =
(RepositoryValue) env.getValue(RepositoryValue.key(key.getRepository()));
if (repository == null) {
return null;
}
candidateRoots = ImmutableList.of(repository.getPath());
} else {
candidateRoots = pkgLocator.get().getPathEntries();
}
for (Path root : candidateRoots) {
RootedPath rootedPath = RootedPath.toRootedPath(root, key.getPackageFragment());
FileValue fileValue;
try {
fileValue = (FileValue) env.getValueOrThrow(FileValue.key(rootedPath),
IOException.class, FileSymlinkException.class, InconsistentFilesystemException.class);
} catch (IOException | FileSymlinkException e) {
throw new ASTLookupFunctionException(new ErrorReadingSkylarkExtensionException(
e.getMessage()), Transience.PERSISTENT);
} catch (InconsistentFilesystemException e) {
throw new ASTLookupFunctionException(e, Transience.PERSISTENT);
}
if (fileValue == null) {
return null;
}
if (fileValue.isFile()) {
return FileLookupResult.file(rootedPath, fileValue.getSize());
}
}
return FileLookupResult.noFile();
}
@Nullable
@Override
public String extractTag(SkyKey skyKey) {
return null;
}
private static final class ASTLookupFunctionException extends SkyFunctionException {
private ASTLookupFunctionException(ErrorReadingSkylarkExtensionException e,
Transience transience) {
super(e, transience);
}
private ASTLookupFunctionException(InconsistentFilesystemException e, Transience transience) {
super(e, transience);
}
}
}
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