Update from Google.

--
MOE_MIGRATED_REVID=85702957

1 files changed, 126 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/vfs/ModifiedFileSet.java b/src/main/java/com/google/devtools/build/lib/vfs/ModifiedFileSet.java
new file mode 100644
index 0000000000..3d6a6387d9
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/vfs/ModifiedFileSet.java
@@ -0,0 +1,126 @@
+// 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.vfs;
+
+import com.google.common.collect.ImmutableSet;
+
+import java.util.Objects;
+
+import javax.annotation.Nullable;
+
+/**
+ * An immutable set of modified source files. The scope of these files is context-dependent; in some
+ * uses this may mean information about all files in the client, while in other uses this may mean
+ * information about some specific subset of files. {@link #EVERYTHING_MODIFIED} can be used to
+ * indicate that all files of interest have been modified.
+ */
+public final class ModifiedFileSet {
+
+  public static final ModifiedFileSet EVERYTHING_MODIFIED = new ModifiedFileSet(null);
+  public static final ModifiedFileSet NOTHING_MODIFIED = new ModifiedFileSet(
+      ImmutableSet.<PathFragment>of());
+
+  @Nullable private final ImmutableSet<PathFragment> modified;
+
+  /**
+   * Whether all files of interest should be treated as potentially modified.
+   */
+  public boolean treatEverythingAsModified() {
+    return modified == null;
+  }
+
+  /**
+   * The set of files of interest that were modified.
+   *
+   * @throws IllegalStateException if {@link #treatEverythingAsModified} returns true.
+   */
+  public ImmutableSet<PathFragment> modifiedSourceFiles() {
+    if (treatEverythingAsModified()) {
+      throw new IllegalStateException();
+    }
+    return modified;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (!(o instanceof ModifiedFileSet)) {
+      return false;
+    }
+    ModifiedFileSet other = (ModifiedFileSet) o;
+    return Objects.equals(modified, other.modified);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(modified);
+  }
+
+  @Override
+  public String toString() {
+    if (this == EVERYTHING_MODIFIED) {
+      return "EVERYTHING_MODIFIED";
+    } else if (this == NOTHING_MODIFIED) {
+      return "NOTHING_MODIFIED";
+    } else {
+      return modified.toString();
+    }
+  }
+
+  private ModifiedFileSet(ImmutableSet<PathFragment> modified) {
+    this.modified = modified;
+  }
+
+  /**
+   * The builder for {@link ModifiedFileSet}.
+   */
+  public static class Builder {
+    private final ImmutableSet.Builder<PathFragment> setBuilder =
+        ImmutableSet.<PathFragment>builder();
+
+    public ModifiedFileSet build() {
+      ImmutableSet<PathFragment> modified = setBuilder.build();
+      return modified.isEmpty() ? NOTHING_MODIFIED : new ModifiedFileSet(modified);
+    }
+
+    public Builder modify(PathFragment pathFragment) {
+      setBuilder.add(pathFragment);
+      return this;
+    }
+
+    public Builder modifyAll(Iterable<PathFragment> pathFragments) {
+      setBuilder.addAll(pathFragments);
+      return this;
+    }
+  }
+
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  public static ModifiedFileSet union(ModifiedFileSet mfs1, ModifiedFileSet mfs2) {
+    if (mfs1.treatEverythingAsModified() || mfs2.treatEverythingAsModified()) {
+      return ModifiedFileSet.EVERYTHING_MODIFIED;
+    }
+    if (mfs1.equals(ModifiedFileSet.NOTHING_MODIFIED)) {
+      return mfs2;
+    }
+    if (mfs2.equals(ModifiedFileSet.NOTHING_MODIFIED)) {
+      return mfs1;
+    }
+    return ModifiedFileSet.builder()
+        .modifyAll(mfs1.modifiedSourceFiles())
+        .modifyAll(mfs2.modifiedSourceFiles())
+        .build();
+  }
+}