1 files changed, 218 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/rules/fileset/FilesetLinks.java b/src/main/java/com/google/devtools/build/lib/rules/fileset/FilesetLinks.java
new file mode 100644
index 0000000000..d523edc356
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+++ b/src/main/java/com/google/devtools/build/lib/rules/fileset/FilesetLinks.java
@@ -0,0 +1,218 @@
+// 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.rules.fileset;
+
+import com.google.common.base.Preconditions;
+import com.google.devtools.build.lib.syntax.FilesetEntry;
+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;
+  }
+}