Move FunctionView from AudioCodingModule to the rtc namespace

webrtc/base/function_view_unittest.cc

+/*
+ *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <memory>
+#include <utility>
+
+#include "webrtc/base/function_view.h"
+#include "webrtc/base/gunit.h"
+
+namespace rtc {
+
+namespace {
+
+int CallWith33(rtc::FunctionView<int(int)> fv) {
+  return fv(33);
+}
+
+}  // namespace
+
+// Test the main use case of FunctionView: implicitly converting a lambda
+// function argument.
+TEST(FunctionViewTest, ImplicitConversion) {
+  EXPECT_EQ(38, CallWith33([](int x) { return x + 5; }));
+}
+
+TEST(FunctionViewTest, IntIntLambdaWithoutState) {
+  auto f = [](int x) { return x + 1; };
+  EXPECT_EQ(18, f(17));
+  rtc::FunctionView<int(int)> fv(f);
+  EXPECT_EQ(18, fv(17));
+}
+
+TEST(FunctionViewTest, IntVoidLambdaWithState) {
+  int x = 13;
+  auto f = [x]() mutable { return ++x; };
+  rtc::FunctionView<int()> fv(f);
+  EXPECT_EQ(14, f());
+  EXPECT_EQ(15, fv());
+  EXPECT_EQ(16, f());
+  EXPECT_EQ(17, fv());
+}
+
+// Ensure that FunctionView handles move-only arguments and return values.
+TEST(FunctionViewTest, UniquePtrPassthrough) {
+  auto f = [](std::unique_ptr<int> x) { return x; };
+  rtc::FunctionView<std::unique_ptr<int>(std::unique_ptr<int>)> fv(f);
+  std::unique_ptr<int> x(new int);
+  int* x_addr = x.get();
+  auto y = fv(std::move(x));
+  EXPECT_EQ(x_addr, y.get());
+}
+
+TEST(FunctionViewTest, CopyConstructor) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  rtc::FunctionView<int()> fv2(fv1);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+TEST(FunctionViewTest, MoveConstructorIsCopy) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  rtc::FunctionView<int()> fv2(std::move(fv1));
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+TEST(FunctionViewTest, CopyAssignment) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  auto f23 = [] { return 23; };
+  rtc::FunctionView<int()> fv2(f23);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(23, fv2());
+  fv2 = fv1;
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+TEST(FunctionViewTest, MoveAssignmentIsCopy) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  auto f23 = [] { return 23; };
+  rtc::FunctionView<int()> fv2(f23);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(23, fv2());
+  fv2 = std::move(fv1);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+TEST(FunctionViewTest, Swap) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  auto f23 = [] { return 23; };
+  rtc::FunctionView<int()> fv2(f23);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(23, fv2());
+  using std::swap;
+  swap(fv1, fv2);
+  EXPECT_EQ(23, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+// Ensure that when you copy-construct a FunctionView, the new object points to
+// the same function as the old one, as opposed to the new object pointing to
+// the old one.
+TEST(FunctionViewTest, CopyConstructorChaining) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  rtc::FunctionView<int()> fv2(fv1);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(17, fv2());
+  auto f23 = [] { return 23; };
+  fv1 = f23;
+  EXPECT_EQ(23, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+// Ensure that when you assign one FunctionView to another, we actually make a
+// copy as opposed to making the second FunctionView point to the first one.
+TEST(FunctionViewTest, CopyAssignmentChaining) {
+  auto f17 = [] { return 17; };
+  rtc::FunctionView<int()> fv1(f17);
+  auto f3 = [] { return 3; };
+  rtc::FunctionView<int()> fv2(f3);
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(3, fv2());
+  fv2 = fv1;
+  EXPECT_EQ(17, fv1());
+  EXPECT_EQ(17, fv2());
+  auto f23 = [] { return 23; };
+  fv1 = f23;
+  EXPECT_EQ(23, fv1());
+  EXPECT_EQ(17, fv2());
+}
+
+}  // namespace rtc