blob: c729465bc47fa2119ad5a4ae985514da2c2d2a8e [file] [log] [blame]
// 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.lib.skyframe;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Interner;
import com.google.devtools.build.lib.concurrent.BlazeInterners;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import com.google.devtools.build.lib.vfs.RootedPath;
import com.google.devtools.build.skyframe.AbstractSkyKey;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyFunctionName;
import com.google.devtools.build.skyframe.SkyKey;
/**
* A {@link SkyFunction} that has the side effect of reporting a file symlink expansion error
* exactly once. This is achieved by forcing the same value key for two logically equivalent
* expansion errors (e.g. ['a' -> 'b' -> 'c' -> 'a/nope'] and ['b' -> 'c' -> 'a' -> 'a/nope']),
* and letting Skyframe do its magic.
*/
public class FileSymlinkInfiniteExpansionUniquenessFunction
extends AbstractChainUniquenessFunction<RootedPath> {
static SkyKey key(ImmutableList<RootedPath> cycle) {
return Key.create(ChainUniquenessUtils.canonicalize(cycle));
}
@AutoCodec.VisibleForSerialization
@AutoCodec
static class Key extends AbstractSkyKey<ImmutableList<RootedPath>> {
private static final Interner<Key> interner = BlazeInterners.newWeakInterner();
private Key(ImmutableList<RootedPath> arg) {
super(arg);
}
@AutoCodec.VisibleForSerialization
@AutoCodec.Instantiator
static Key create(ImmutableList<RootedPath> arg) {
return interner.intern(new Key(arg));
}
@Override
public SkyFunctionName functionName() {
return SkyFunctions.FILE_SYMLINK_INFINITE_EXPANSION_UNIQUENESS;
}
}
@Override
protected String elementToString(RootedPath elt) {
return elt.asPath().toString();
}
@Override
protected String getConciseDescription() {
return "infinite symlink expansion";
}
@Override
protected String getHeaderMessage() {
return "[start of symlink chain]";
}
@Override
protected String getFooterMessage() {
return "[end of symlink chain]";
}
}