1 files changed, 137 insertions, 0 deletions
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 0000000000..6127ceec80
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+++ 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;
+  }
+}