Update from Google.
--
MOE_MIGRATED_REVID=85702957
diff --git a/src/main/java/com/google/devtools/build/lib/exec/SymlinkTreeHelper.java b/src/main/java/com/google/devtools/build/lib/exec/SymlinkTreeHelper.java
new file mode 100644
index 0000000..6127cee
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/exec/SymlinkTreeHelper.java
@@ -0,0 +1,137 @@
+// 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.exec;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.devtools.build.lib.actions.AbstractAction;
+import com.google.devtools.build.lib.actions.ActionExecutionContext;
+import com.google.devtools.build.lib.actions.BaseSpawn;
+import com.google.devtools.build.lib.actions.ExecException;
+import com.google.devtools.build.lib.actions.ResourceManager;
+import com.google.devtools.build.lib.actions.ResourceSet;
+import com.google.devtools.build.lib.analysis.config.BinTools;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.shell.CommandException;
+import com.google.devtools.build.lib.util.CommandBuilder;
+import com.google.devtools.build.lib.util.OsUtils;
+import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.PathFragment;
+
+import java.util.List;
+
+/**
+ * Helper class responsible for the symlink tree creation.
+ * Used to generate runfiles and fileset symlink farms.
+ */
+public final class SymlinkTreeHelper {
+
+ private static final String BUILD_RUNFILES = "build-runfiles" + OsUtils.executableExtension();
+
+ /**
+ * These actions run faster overall when serialized, because most of their
+ * cost is in the ext2 block allocator, and there's less seeking required if
+ * their directory creations get non-interleaved allocations. So we give them
+ * a huge resource cost.
+ */
+ public static final ResourceSet RESOURCE_SET = new ResourceSet(1000, 0.5, 0.75);
+
+ private final PathFragment inputManifest;
+ private final PathFragment symlinkTreeRoot;
+ private final boolean filesetTree;
+
+ /**
+ * Creates SymlinkTreeHelper instance. Can be used independently of
+ * SymlinkTreeAction.
+ *
+ * @param inputManifest exec path to the input runfiles manifest
+ * @param symlinkTreeRoot exec path to the symlink tree location
+ * @param filesetTree true if this is fileset symlink tree,
+ * false if this is a runfiles symlink tree.
+ */
+ public SymlinkTreeHelper(PathFragment inputManifest, PathFragment symlinkTreeRoot,
+ boolean filesetTree) {
+ this.inputManifest = inputManifest;
+ this.symlinkTreeRoot = symlinkTreeRoot;
+ this.filesetTree = filesetTree;
+ }
+
+ public PathFragment getSymlinkTreeRoot() { return symlinkTreeRoot; }
+
+ /**
+ * Creates a symlink tree using a CommandBuilder. This means that the symlink
+ * tree will always be present on the developer's workstation. Useful when
+ * running commands locally.
+ *
+ * Warning: this method REALLY executes the command on the box Blaze was
+ * run on, without any kind of synchronization, locking, or anything else.
+ *
+ * @param config the configuration that is used for creating the symlink tree.
+ * @throws CommandException
+ */
+ public void createSymlinksUsingCommand(Path execRoot,
+ BuildConfiguration config, BinTools binTools) throws CommandException {
+ List<String> argv = getSpawnArgumentList(execRoot, binTools);
+
+ CommandBuilder builder = new CommandBuilder();
+ builder.addArgs(argv);
+ builder.setWorkingDir(execRoot);
+ builder.build().execute();
+ }
+
+ /**
+ * Creates symlink tree using appropriate method. At this time tree
+ * always created using build-runfiles helper application.
+ *
+ * Note: method may try to acquire resources - meaning that it would
+ * block for undetermined period of time. If it is interrupted during
+ * that wait, ExecException will be thrown but interrupted bit will be
+ * preserved.
+ *
+ * @param action action instance that requested symlink tree creation
+ * @param actionExecutionContext Services that are in the scope of the action.
+ */
+ public void createSymlinks(AbstractAction action, ActionExecutionContext actionExecutionContext,
+ BinTools binTools) throws ExecException, InterruptedException {
+ List<String> args = getSpawnArgumentList(
+ actionExecutionContext.getExecutor().getExecRoot(), binTools);
+ try {
+ ResourceManager.instance().acquireResources(action, RESOURCE_SET);
+ actionExecutionContext.getExecutor().getSpawnActionContext(action.getMnemonic()).exec(
+ new BaseSpawn.Local(args, ImmutableMap.<String, String>of(), action),
+ actionExecutionContext);
+ } finally {
+ ResourceManager.instance().releaseResources(action, RESOURCE_SET);
+ }
+ }
+
+ /**
+ * Returns the complete argument list build-runfiles has to be called with.
+ */
+ private List<String> getSpawnArgumentList(Path execRoot, BinTools binTools) {
+ List<String> args = Lists.newArrayList(
+ execRoot.getRelative(binTools.getExecPath(BUILD_RUNFILES))
+ .getPathString());
+
+ if (filesetTree) {
+ args.add("--allow_relative");
+ args.add("--use_metadata");
+ }
+
+ args.add(inputManifest.getPathString());
+ args.add(symlinkTreeRoot.getPathString());
+
+ return args;
+ }
+}
