// 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.rules.fileset;
import com.google.devtools.build.lib.packages.FilesetEntry;
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 java.io.IOException;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* FilesetLinks manages the set of links added to a Fileset. If two links conflict, the first wins.
*
* <p>FilesetLinks is FileSystem-aware. For example, if you first create a link
* (a/b/c, foo), a subsequent call to link (a/b, bar) is a no-op.
* This is because the first link requires us to create a directory "a/b",
* so "a/b" cannot also link to "bar".
*
* <p>TODO(bazel-team): Consider warning if we have such a conflict; we don't do that currently.
*/
public interface FilesetLinks {
/**
* Get late directory information for a source.
*
* @param src The source to search for.
* @return The late directory info, or null if none was found.
*/
public LateDirectoryInfo getLateDirectoryInfo(PathFragment src);
public boolean putLateDirectoryInfo(PathFragment src, LateDirectoryInfo lateDir);
/**
* Add specified file as a symlink.
*
* The behavior when the target file is a symlink depends on the
* symlinkBehavior parameter (see comments for FilesetEntry.SymlinkBehavior).
*
* @param src The root-relative symlink path.
* @param target The symlink target.
*/
public void addFile(PathFragment src, Path target, String metadata,
FilesetEntry.SymlinkBehavior symlinkBehavior)
throws IOException;
/**
* Add all late directories as symlinks. This function should be called only
* after all recursions have completed, but before getData or getSymlinks are
* called.
*/
public void addLateDirectories() throws IOException;
/**
* Adds the given symlink to the tree.
*
* @param fromFrag The root-relative symlink path.
* @param toFrag The symlink target.
* @return true iff the symlink was added.
*/
public boolean addLink(PathFragment fromFrag, PathFragment toFrag, String dataVal);
/**
* @return The unmodifiable map of symlinks.
*/
public Map<PathFragment, PathFragment> getSymlinks();
/**
* @return The unmodifiable map of metadata.
*/
public Map<PathFragment, String> getData();
/**
* A data structure for containing all the information about a directory that
* is late-added. This means the directory is skipped unless we need to
* recurse into it later. If the directory is never recursed into, we will
* create a symlink directly to it.
*/
public static final class LateDirectoryInfo {
// The constructors are private. Use the factory functions below to create
// instances of this class.
/** Construct a stub LateDirectoryInfo object. */
private LateDirectoryInfo() {
this.added = new AtomicBoolean(true);
// Shut up the compiler.
this.target = null;
this.src = null;
this.pkgMode = SubpackageMode.IGNORE;
this.metadata = null;
this.symlinkBehavior = null;
}
/** Construct a normal LateDirectoryInfo object. */
private LateDirectoryInfo(Path target, PathFragment src, SubpackageMode pkgMode,
String metadata, FilesetEntry.SymlinkBehavior symlinkBehavior) {
this.target = target;
this.src = src;
this.pkgMode = pkgMode;
this.metadata = metadata;
this.symlinkBehavior = symlinkBehavior;
this.added = new AtomicBoolean(false);
}
/** @return The target path for the symlink. The target is the referent. */
public Path getTarget() {
return target;
}
/**
* @return The source path for the symlink. The source is the place the
* symlink will be written. */
public PathFragment getSrc() {
return src;
}
/**
* @return Whether we should show a warning if we cross a package boundary
* when recursing into this directory.
*/
public SubpackageMode getPkgMode() {
return pkgMode;
}
/**
* @return The metadata we will write into the manifest if we symlink to
* this directory.
*/
public String getMetadata() {
return metadata;
}
/**
* @return How to perform the symlinking if the source happens to be a
* symlink itself.
*/
public FilesetEntry.SymlinkBehavior getTargetSymlinkBehavior() {
return Preconditions.checkNotNull(symlinkBehavior,
"should not call this method on stub instances");
}
/**
* Atomically checks if the late directory has been added to the manifest
* and marks it as added. If this function returns true, it is the
* responsibility of the caller to recurse into the late directory.
* Otherwise, some other caller has already, or is in the process of
* recursing into it.
* @return Whether the caller should recurse into the late directory.
*/
public boolean shouldAdd() {
return !added.getAndSet(true);
}
/**
* Create a stub LateDirectoryInfo that is already marked as added.
* @return The new LateDirectoryInfo object.
*/
public static LateDirectoryInfo createStub() {
return new LateDirectoryInfo();
}
/**
* Create a LateDirectoryInfo object with the specified attributes.
* @param target The directory to which the symlinks will refer.
* @param src The location at which to create the symlink.
* @param pkgMode How to handle recursion into another package.
* @param metadata The metadata for the directory to write into the
* manifest if we symlink it directly.
* @return The new LateDirectoryInfo object.
*/
public static LateDirectoryInfo create(Path target, PathFragment src, SubpackageMode pkgMode,
String metadata, FilesetEntry.SymlinkBehavior symlinkBehavior) {
return new LateDirectoryInfo(target, src, pkgMode, metadata, symlinkBehavior);
}
/**
* The target directory to which the symlink will point.
* Note this is a real path on the filesystem and can't be compared to src
* or any source (key) in the links map.
*/
private final Path target;
/** The referent of the symlink. */
private final PathFragment src;
/** Whether to show cross package boundary warnings / errors. */
private final SubpackageMode pkgMode;
/** The metadata to write into the manifest file. */
private final String metadata;
/** How to perform the symlinking if the source happens to be a symlink itself. */
private final FilesetEntry.SymlinkBehavior symlinkBehavior;
/** Whether the directory has already been recursed into. */
private final AtomicBoolean added;
}
/** How to handle filesets that cross subpackages. */
public static enum SubpackageMode {
ERROR, WARNING, IGNORE;
}
}