Initial TreeSortedMap and SortedMap in C++ (#980)

* Prepare for TreeSortedMap
  * Factor out SortedMapBase
  * Move ArraySortedMap to impl
  * Factor out SortedMap testing utilities

* Add a minimal TreeSortedMap

* Add the public SortedMap type

5 files changed, 291 insertions, 132 deletions

diff --git a/Firestore/core/test/firebase/firestore/immutable/CMakeLists.txt b/Firestore/core/test/firebase/firestore/immutable/CMakeLists.txt
index e7b0b6e..753e2d0 100644
--- a/Firestore/core/test/firebase/firestore/immutable/CMakeLists.txt
+++ b/Firestore/core/test/firebase/firestore/immutable/CMakeLists.txt
@@ -16,6 +16,9 @@ cc_test(
   firebase_firestore_immutable_test
   SOURCES
     array_sorted_map_test.cc
+    testing.h
+    sorted_map_test.cc
+    tree_sorted_map_test.cc
   DEPENDS
     firebase_firestore_immutable
     firebase_firestore_util
diff --git a/Firestore/core/test/firebase/firestore/immutable/array_sorted_map_test.cc b/Firestore/core/test/firebase/firestore/immutable/array_sorted_map_test.cc
index 260506b..fceab7d 100644
--- a/Firestore/core/test/firebase/firestore/immutable/array_sorted_map_test.cc
+++ b/Firestore/core/test/firebase/firestore/immutable/array_sorted_map_test.cc
@@ -20,127 +20,18 @@
 #include <random>
 
 #include "Firestore/core/src/firebase/firestore/util/secure_random.h"
+
+#include "Firestore/core/test/firebase/firestore/immutable/testing.h"
 #include "gtest/gtest.h"
 
 namespace firebase {
 namespace firestore {
 namespace immutable {
+namespace impl {
 
 typedef ArraySortedMap<int, int> IntMap;
 constexpr IntMap::size_type kFixedSize = IntMap::kFixedSize;
 
-template <typename K, typename V>
-testing::AssertionResult NotFound(const ArraySortedMap<K, V>& set,
-                                  const K& key) {
-  auto found = set.find(key);
-  if (found == set.end()) {
-    return testing::AssertionSuccess();
-  } else {
-    return testing::AssertionFailure()
-           << "Should not have found (" << found->first << ", " << found->second
-           << ") @ " << found;
-  }
-}
-
-template <typename K, typename V>
-testing::AssertionResult Found(const ArraySortedMap<K, V>& map,
-                               const K& key,
-                               const V& expected) {
-  auto found = map.find(key);
-  if (found == map.end()) {
-    return testing::AssertionFailure() << "Did not find key " << key;
-  }
-  if (found->second == expected) {
-    return testing::AssertionSuccess();
-  } else {
-    return testing::AssertionFailure() << "Found entry was (" << found->first
-                                       << ", " << found->second << ")";
-  }
-}
-
-/**
- * Creates a vector containing a sequence of integers from the given starting
- * element up to, but not including, the given end element, with values
- * incremented by the given step.
- *
- * If step is negative the sequence is in descending order (but still starting
- * at start and ending before end).
- */
-std::vector<int> Sequence(int start, int end, int step = 1) {
-  std::vector<int> result;
-  if (step > 0) {
-    for (int i = start; i < end; i += step) {
-      result.push_back(i);
-    }
-  } else {
-    for (int i = start; i > end; i += step) {
-      result.push_back(i);
-    }
-  }
-  return result;
-}
-
-/**
- * Creates a vector containing a sequence of integers with the given number of
- * elements, from zero up to, but not including the given value.
- */
-std::vector<int> Sequence(int num_elements) {
-  return Sequence(0, num_elements);
-}
-
-/**
- * Creates a copy of the given vector with contents shuffled randomly.
- */
-std::vector<int> Shuffled(const std::vector<int>& values) {
-  std::vector<int> result(values);
-  util::SecureRandom rng;
-  std::shuffle(result.begin(), result.end(), rng);
-  return result;
-}
-
-/**
- * Creates a copy of the given vector with contents sorted.
- */
-std::vector<int> Sorted(const std::vector<int>& values) {
-  std::vector<int> result(values);
-  std::sort(result.begin(), result.end());
-  return result;
-}
-
-/**
- * Creates a vector of pairs where each pair has the same first and second
- * corresponding to an element in the given vector.
- */
-std::vector<std::pair<int, int>> Pairs(const std::vector<int>& values) {
-  std::vector<std::pair<int, int>> result;
-  for (auto&& value : values) {
-    result.emplace_back(value, value);
-  }
-  return result;
-}
-
-/**
- * Creates an ArraySortedMap by inserting a pair for each value in the vector.
- * Each pair will have the same key and value.
- */
-IntMap ToMap(const std::vector<int>& values) {
-  IntMap result;
-  for (auto&& value : values) {
-    result = result.insert(value, value);
-  }
-  return result;
-}
-
-/**
- * Appends the contents of the given container to a new vector.
- */
-template <typename Container>
-std::vector<typename Container::value_type> Append(const Container& container) {
-  std::vector<typename Container::value_type> result;
-  result.insert(result.begin(), container.begin(), container.end());
-  return result;
-}
-
 // TODO(wilhuff): ReverseTraversal
 
 #define ASSERT_SEQ_EQ(x, y) ASSERT_EQ((x), Append(y));
@@ -167,7 +58,7 @@ TEST(ArraySortedMap, RemoveKeyValuePair) {
 }
 
 TEST(ArraySortedMap, MoreRemovals) {
-  IntMap map = IntMap()
+  IntMap map = IntMap{}
                    .insert(1, 1)
                    .insert(50, 50)
                    .insert(3, 3)
@@ -230,7 +121,7 @@ TEST(ArraySortedMap, Increasing) {
 }
 
 TEST(ArraySortedMap, Override) {
-  IntMap map = IntMap().insert(10, 10).insert(10, 8);
+  IntMap map = IntMap{}.insert(10, 10).insert(10, 8);
 
   ASSERT_TRUE(Found(map, 10, 8));
   ASSERT_FALSE(Found(map, 10, 10));
@@ -238,7 +129,7 @@ TEST(ArraySortedMap, Override) {
 
 TEST(ArraySortedMap, ChecksSize) {
   std::vector<int> to_insert = Sequence(kFixedSize);
-  IntMap map = ToMap(to_insert);
+  IntMap map = ToMap<IntMap>(to_insert);
 
   // Replacing an existing entry should not hit increase size
   map = map.insert(5, 10);
@@ -247,25 +138,11 @@ TEST(ArraySortedMap, ChecksSize) {
   ASSERT_ANY_THROW(map.insert(next, next));
 }
 
-TEST(ArraySortedMap, Empty) {
-  IntMap map = IntMap().insert(10, 10).erase(10);
-  EXPECT_TRUE(map.empty());
-  EXPECT_EQ(0u, map.size());
-  EXPECT_TRUE(NotFound(map, 1));
-  EXPECT_TRUE(NotFound(map, 10));
-}
-
 TEST(ArraySortedMap, EmptyGet) {
   IntMap map;
   EXPECT_TRUE(NotFound(map, 10));
 }
 
-TEST(ArraySortedMap, EmptySize) {
-  IntMap map;
-  EXPECT_TRUE(map.empty());
-  EXPECT_EQ(0u, map.size());
-}
-
 TEST(ArraySortedMap, EmptyRemoval) {
   IntMap map;
   IntMap new_map = map.erase(1);
@@ -281,7 +158,7 @@ TEST(ArraySortedMap, InsertionAndRemovalOfMaxItems) {
   std::vector<int> to_remove = Shuffled(to_insert);
 
   // Add them to the map
-  IntMap map = ToMap(to_insert);
+  IntMap map = ToMap<IntMap>(to_insert);
   ASSERT_EQ(expected_size, map.size())
       << "Check if all N objects are in the map";
 
@@ -297,7 +174,7 @@ TEST(ArraySortedMap, InsertionAndRemovalOfMaxItems) {
 TEST(ArraySortedMap, BalanceProblem) {
   std::vector<int> to_insert{1, 7, 8, 5, 2, 6, 4, 0, 3};
 
-  IntMap map = ToMap(to_insert);
+  IntMap map = ToMap<IntMap>(to_insert);
   ASSERT_SEQ_EQ(Pairs(Sorted(to_insert)), map);
 }
 
@@ -306,7 +183,7 @@ TEST(ArraySortedMap, BalanceProblem) {
 // TODO(wilhuff): IndexOf
 
 TEST(ArraySortedMap, AvoidsCopying) {
-  IntMap map = IntMap().insert(10, 20);
+  IntMap map = IntMap{}.insert(10, 20);
   auto found = map.find(10);
   ASSERT_NE(found, map.end());
   EXPECT_EQ(20, found->second);
@@ -321,6 +198,7 @@ TEST(ArraySortedMap, AvoidsCopying) {
   EXPECT_EQ(found, duped_found);
 }
 
+}  // namespace impl
 }  // namespace immutable
 }  // namespace firestore
 }  // namespace firebase
diff --git a/Firestore/core/test/firebase/firestore/immutable/sorted_map_test.cc b/Firestore/core/test/firebase/firestore/immutable/sorted_map_test.cc
new file mode 100644
index 0000000..44dca50
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/immutable/sorted_map_test.cc
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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 "Firestore/core/src/firebase/firestore/immutable/sorted_map.h"
+
+#include <numeric>
+#include <random>
+
+#include "Firestore/core/src/firebase/firestore/immutable/array_sorted_map.h"
+#include "Firestore/core/src/firebase/firestore/immutable/tree_sorted_map.h"
+#include "Firestore/core/src/firebase/firestore/util/secure_random.h"
+
+#include "Firestore/core/test/firebase/firestore/immutable/testing.h"
+#include "gtest/gtest.h"
+
+using firebase::firestore::immutable::impl::SortedMapBase;
+
+namespace firebase {
+namespace firestore {
+namespace immutable {
+
+using SizeType = SortedMapBase::size_type;
+
+template <typename MapType>
+struct TestPolicy {
+  // TODO(mcg): increase beyond what ArraySortedMap supports
+  static const SizeType kFixedSize = SortedMapBase::kFixedSize;
+};
+
+template <typename IntMap>
+class SortedMapTest : public ::testing::Test {
+ public:
+  template <typename Integer = SizeType>
+  Integer fixed_size() {
+    return static_cast<Integer>(TestPolicy<IntMap>::kFixedSize);
+  }
+};
+
+typedef ::testing::Types<SortedMap<int, int>,
+                         impl::ArraySortedMap<int, int>,
+                         impl::TreeSortedMap<int, int>>
+    TestedTypes;
+TYPED_TEST_CASE(SortedMapTest, TestedTypes);
+
+TYPED_TEST(SortedMapTest, EmptySize) {
+  TypeParam map;
+  EXPECT_TRUE(map.empty());
+  EXPECT_EQ(0u, map.size());
+}
+
+TYPED_TEST(SortedMapTest, Empty) {
+  TypeParam map = TypeParam{}.insert(10, 10).erase(10);
+  EXPECT_TRUE(map.empty());
+  EXPECT_EQ(0u, map.size());
+
+  // TODO(wilhuff): re-add find
+  // EXPECT_TRUE(NotFound(map, 1));
+  // EXPECT_TRUE(NotFound(map, 10));
+}
+
+}  // namespace immutable
+}  // namespace firestore
+}  // namespace firebase
diff --git a/Firestore/core/test/firebase/firestore/immutable/testing.h b/Firestore/core/test/firebase/firestore/immutable/testing.h
new file mode 100644
index 0000000..337140f
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/immutable/testing.h
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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 FIRESTORE_CORE_TEST_FIREBASE_FIRESTORE_IMMUTABLE_TESTING_H_
+#define FIRESTORE_CORE_TEST_FIREBASE_FIRESTORE_IMMUTABLE_TESTING_H_
+
+#include <algorithm>
+#include <utility>
+#include <vector>
+
+#include "Firestore/core/src/firebase/firestore/util/secure_random.h"
+#include "gtest/gtest.h"
+
+namespace firebase {
+namespace firestore {
+namespace immutable {
+
+template <typename Container, typename K>
+testing::AssertionResult NotFound(const Container& map, const K& key) {
+  auto found = map.find(key);
+  if (found == map.end()) {
+    return testing::AssertionSuccess();
+  } else {
+    return testing::AssertionFailure()
+           << "Should not have found (" << found->first << ", " << found->second
+           << ")";
+  }
+}
+
+template <typename Container, typename K, typename V>
+testing::AssertionResult Found(const Container& map,
+                               const K& key,
+                               const V& expected) {
+  auto found = map.find(key);
+  if (found == map.end()) {
+    return testing::AssertionFailure() << "Did not find key " << key;
+  }
+  if (found->second == expected) {
+    return testing::AssertionSuccess();
+  } else {
+    return testing::AssertionFailure() << "Found entry was (" << found->first
+                                       << ", " << found->second << ")";
+  }
+}
+
+/** Creates an empty vector (for readability). */
+inline std::vector<int> Empty() {
+  return {};
+}
+
+/**
+ * Creates a vector containing a sequence of integers from the given starting
+ * element up to, but not including, the given end element, with values
+ * incremented by the given step.
+ *
+ * If step is negative the sequence is in descending order (but still starting
+ * at start and ending before end).
+ */
+inline std::vector<int> Sequence(int start, int end, int step = 1) {
+  std::vector<int> result;
+  if (step > 0) {
+    for (int i = start; i < end; i += step) {
+      result.push_back(i);
+    }
+  } else {
+    for (int i = start; i > end; i += step) {
+      result.push_back(i);
+    }
+  }
+  return result;
+}
+
+/**
+ * Creates a vector containing a sequence of integers with the given number of
+ * elements, from zero up to, but not including the given value.
+ */
+inline std::vector<int> Sequence(int num_elements) {
+  return Sequence(0, num_elements);
+}
+
+/**
+ * Creates a copy of the given vector with contents shuffled randomly.
+ */
+inline std::vector<int> Shuffled(const std::vector<int>& values) {
+  std::vector<int> result{values};
+  util::SecureRandom rng;
+  std::shuffle(result.begin(), result.end(), rng);
+  return result;
+}
+
+/**
+ * Creates a copy of the given vector with contents sorted.
+ */
+inline std::vector<int> Sorted(const std::vector<int>& values) {
+  std::vector<int> result{values};
+  std::sort(result.begin(), result.end());
+  return result;
+}
+
+/**
+ * Creates a copy of the given vector with contents reversed.
+ */
+inline std::vector<int> Reversed(const std::vector<int>& values) {
+  std::vector<int> result{values};
+  std::reverse(result.begin(), result.end());
+  return result;
+}
+
+/**
+ * Creates a vector of pairs where each pair has the same first and second
+ * corresponding to an element in the given vector.
+ */
+inline std::vector<std::pair<int, int>> Pairs(const std::vector<int>& values) {
+  std::vector<std::pair<int, int>> result;
+  for (auto&& value : values) {
+    result.emplace_back(value, value);
+  }
+  return result;
+}
+
+/**
+ * Creates a SortedMap by inserting a pair for each value in the vector.
+ * Each pair will have the same key and value.
+ */
+template <typename Container>
+Container ToMap(const std::vector<int>& values) {
+  Container result;
+  for (auto&& value : values) {
+    result = result.insert(value, value);
+  }
+  return result;
+}
+
+/**
+ * Appends the contents of the given container to a new vector.
+ */
+template <typename Container>
+std::vector<typename Container::value_type> Append(const Container& container) {
+  return {container.begin(), container.end()};
+}
+
+#define ASSERT_SEQ_EQ(x, y) ASSERT_EQ((x), Append(y));
+#define EXPECT_SEQ_EQ(x, y) EXPECT_EQ((x), Append(y));
+
+}  // namespace immutable
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_TEST_FIREBASE_FIRESTORE_IMMUTABLE_TESTING_H_
diff --git a/Firestore/core/test/firebase/firestore/immutable/tree_sorted_map_test.cc b/Firestore/core/test/firebase/firestore/immutable/tree_sorted_map_test.cc
new file mode 100644
index 0000000..7a96b67
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/immutable/tree_sorted_map_test.cc
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2018 Google
+ *
+ * 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 "Firestore/core/src/firebase/firestore/immutable/tree_sorted_map.h"
+
+#include "Firestore/core/src/firebase/firestore/util/secure_random.h"
+#include "Firestore/core/test/firebase/firestore/immutable/testing.h"
+#include "gtest/gtest.h"
+
+namespace firebase {
+namespace firestore {
+namespace immutable {
+namespace impl {
+
+typedef TreeSortedMap<int, int> IntMap;
+
+TEST(TreeSortedMap, EmptySize) {
+  IntMap map;
+  EXPECT_TRUE(map.empty());
+  EXPECT_EQ(0u, map.size());
+  EXPECT_EQ(Color::Black, map.root().color());
+}
+
+}  // namespace impl
+}  // namespace immutable
+}  // namespace firestore
+}  // namespace firebase