add delta update class. (envoyproxy#74)

mixerclient/BUILD

@@ -28,6 +28,8 @@ cc_library(
         "src/cache_key_set.h",
         "src/client_impl.cc",
         "src/client_impl.h",
+        "src/delta_update.cc",
+        "src/delta_update.h",
         "src/signature.cc",
         "src/signature.h",
         "src/quota_cache.cc",
@@ -122,6 +124,17 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "delta_update_test",
+    size = "small",
+    srcs = ["src/delta_update_test.cc"],
+    linkstatic = 1,
+    deps = [
+        ":mixer_client_lib",
+        "//external:googletest_main",
+    ],
+)
+
 cc_test(
     name = "quota_cache_test",
     size = "small",

mixerclient/src/delta_update.cc

@@ -0,0 +1,81 @@
+/* Copyright 2017 Istio Authors. 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.
+ */
+#include "src/delta_update.h"
+
+#include <set>
+
+namespace istio {
+namespace mixer_client {
+namespace {
+
+class DeltaUpdateImpl : public DeltaUpdate {
+ public:
+  // Start a update for a request.
+  void Start() override {
+    prev_set_.clear();
+    for (const auto& it : prev_map_) {
+      prev_set_.insert(it.first);
+    }
+  }
+
+  bool Check(int index, const Attributes::Value& value) override {
+    bool same = false;
+    const auto& it = prev_map_.find(index);
+    if (it != prev_map_.end()) {
+      if (it->second.type == value.type && it->second == value) {
+        same = true;
+      }
+    }
+    if (!same) {
+      prev_map_[index] = value;
+    }
+    prev_set_.erase(index);
+    return same;
+  }
+
+  // "deleted" is not supported for now. If some attributes are missing,
+  // return false to indicate delta update is not supported.
+  bool Finish() override { return prev_set_.empty(); }
+
+ private:
+  // The remaining attributes from previous.
+  std::set<int> prev_set_;
+
+  // The attribute map from previous.
+  std::map<int, Attributes::Value> prev_map_;
+};
+
+// An optimization for non-delta update case.
+class DeltaUpdateNoOpImpl : public DeltaUpdate {
+ public:
+  void Start() override {}
+  bool Check(int index, const Attributes::Value& value) override {
+    return false;
+  }
+  bool Finish() override { return true; }
+};
+
+}  // namespace
+
+std::unique_ptr<DeltaUpdate> DeltaUpdate::Create() {
+  return std::unique_ptr<DeltaUpdate>(new DeltaUpdateImpl);
+}
+
+std::unique_ptr<DeltaUpdate> DeltaUpdate::CreateNoOp() {
+  return std::unique_ptr<DeltaUpdate>(new DeltaUpdateNoOpImpl);
+}
+
+}  // namespace mixer_client
+}  // namespace istio

mixerclient/src/delta_update.h

@@ -0,0 +1,57 @@
+/* Copyright 2017 Istio Authors. 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.
+ */
+
+#ifndef MIXERCLIENT_DELTA_UPDATE_H
+#define MIXERCLIENT_DELTA_UPDATE_H
+
+#include "include/attribute.h"
+
+#include <memory>
+
+namespace istio {
+namespace mixer_client {
+
+// A class to support attribute delta update.
+// It has previous attribute values and check
+// for the current one.
+class DeltaUpdate {
+ public:
+  virtual ~DeltaUpdate() {}
+
+  // Start a new delta update
+  virtual void Start() = 0;
+
+  // Check an attribute, return true if it is in the previous
+  // set with same value, so no need to send it again.
+  // Each attribute in the current set needs to call this method.
+  virtual bool Check(int index, const Attributes::Value& value) = 0;
+
+  // Finish a delta update.
+  // Return false if delta update is not supported.
+  // For example, "deleted" is not supported, if some attributes are
+  // missing, delta update will not be supported.
+  virtual bool Finish() = 0;
+
+  // Create an instance.
+  static std::unique_ptr<DeltaUpdate> Create();
+
+  // Create an no-op instance; an optimization for no delta update cases.
+  static std::unique_ptr<DeltaUpdate> CreateNoOp();
+};
+
+}  // namespace mixer_client
+}  // namespace istio
+
+#endif  // MIXERCLIENT_DELTA_UPDATE_H

mixerclient/src/delta_update_test.cc

@@ -0,0 +1,77 @@
+/* Copyright 2017 Istio Authors. 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.
+ */
+
+#include "src/delta_update.h"
+#include "gtest/gtest.h"
+
+namespace istio {
+namespace mixer_client {
+
+class DeltaUpdateTest : public ::testing::Test {
+ public:
+  void SetUp() {
+    string_map_value_ = Attributes::StringMapValue({{"foo", "bar"}});
+    update_ = DeltaUpdate::Create();
+
+    update_->Start();
+    EXPECT_FALSE(update_->Check(1, Attributes::Int64Value(1)));
+    EXPECT_FALSE(update_->Check(2, Attributes::Int64Value(2)));
+    EXPECT_FALSE(update_->Check(3, string_map_value_));
+    EXPECT_TRUE(update_->Finish());
+  }
+
+  std::unique_ptr<DeltaUpdate> update_;
+  Attributes::Value string_map_value_;
+};
+
+TEST_F(DeltaUpdateTest, TestUpdateNoDelete) {
+  update_->Start();
+  // 1: value is the same.
+  EXPECT_TRUE(update_->Check(1, Attributes::Int64Value(1)));
+  // 2: value is different.
+  EXPECT_FALSE(update_->Check(2, Attributes::Int64Value(3)));
+  // 3: compare string map.
+  EXPECT_TRUE(update_->Check(3, string_map_value_));
+  // 4: an new attribute.
+  EXPECT_FALSE(update_->Check(4, Attributes::Int64Value(4)));
+  // No missing item
+  EXPECT_TRUE(update_->Finish());
+}
+
+TEST_F(DeltaUpdateTest, TestUpdateWithDelete) {
+  update_->Start();
+  // 1: value is the same.
+  EXPECT_TRUE(update_->Check(1, Attributes::Int64Value(1)));
+
+  // 2: is missing
+
+  // 3: compare string map
+  EXPECT_FALSE(update_->Check(3, Attributes::StringMapValue({})));
+
+  // 4: an new attribute.
+  EXPECT_FALSE(update_->Check(4, Attributes::Int64Value(4)));
+
+  // There is a missing item
+  EXPECT_FALSE(update_->Finish());
+}
+
+TEST_F(DeltaUpdateTest, TestDifferentType) {
+  update_->Start();
+  // 1 is differnt type.
+  EXPECT_FALSE(update_->Check(1, Attributes::StringValue("")));
+}
+
+}  // namespace mixer_client
+}  // namespace istio