Pull cacheinvalidations code directory into chromium repo.

third_party/cacheinvalidation/src/java/com/google/ipc/invalidation/ticl/DigestStore.java

Index: third_party/cacheinvalidation/src/java/com/google/ipc/invalidation/ticl/DigestStore.java
diff --git a/third_party/cacheinvalidation/src/java/com/google/ipc/invalidation/ticl/DigestStore.java b/third_party/cacheinvalidation/src/java/com/google/ipc/invalidation/ticl/DigestStore.java
new file mode 100644
index 0000000000000000000000000000000000000000..05bde244140b9afe803aac9e8a27e4d95ce57a16
--- /dev/null
+++ b/third_party/cacheinvalidation/src/java/com/google/ipc/invalidation/ticl/DigestStore.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * 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.ipc.invalidation.ticl;
+
+import java.util.Collection;
+
+/**
+ * Interface for a store that allows objects to be added/removed along with
+ * the ability to get the digest for the whole or partial set of those objects.
+ *
+ * @param <ElementType> the type of the element stored in this
+ *
+ */
+public interface DigestStore<ElementType> {
+
+  /** Returns the number of elements. */
+  int size();
+
+  /** Returns whether {@code element} is in the store. */
+  boolean contains(ElementType element);
+
+  /**
+   * Returns a digest of the desired objects.
+   * <p>
+   * NOTE: the digest computations <b>MUST NOT</b> depend on the order in which the elements
+   * were added.
+   */
+  byte[] getDigest();
+
+  /**
+   * Returns the elements whose digest prefixes begin with the bit prefix {@code digestPrefix}.
+   * {@code prefixLen} is the length of {@code digestPrefix} in bits, which may be less than
+   * {@code digestPrefix.length} (and may be 0). The implementing class can return *more* objects
+   * than what has been specified by {@code digestPrefix}, e.g., it could return all the objects
+   * in the store.
+   */
+  Collection<ElementType> getElements(byte[] digestPrefix, int prefixLen);
+
+  /**
+   * Adds {@code element} to the store. No-op if {@code element} is already present.
+   * @return whether the element was added
+   */
+  boolean add(ElementType element);
+
+  /**
+   * Adds {@code elements} to the store. If any element in {@code elements} is already present,
+   * the addition is a no-op for that element.
+   * @return the elements that were added
+   */
+  Collection<ElementType> add(Collection<ElementType> elements);
+
+  /**
+   * Removes {@code element} from the store. No-op if {@code element} is not present.
+   * @return whether the element was removed
+   */
+  boolean remove(ElementType element);
+
+  /**
+   * Remove {@code elements} to the store. If any element in {@code elements} is not present, the
+   * removal is a no-op for that element.
+   * @return the elements that were removed
+   */
+  Collection<ElementType> remove(Collection<ElementType> elements);
+
+  /** Removes all elements in this and returns them. */
+  Collection<ElementType> removeAll();
+}