commit 30abc364443c6070bfe174946ded0f4d31d77e75
author Karl Wiberg <kwiberg@webrtc.org> Mon Feb 04 12:07:18 2019
committer Commit Bot <commit-bot@chromium.org> Mon Feb 04 13:42:20 2019
tree d6784ebf75dd02cca22a4dd4b2426e7cfece7015
parent ee61f9440a4929cea43526eaf32e6a1674fba524

ArrayView: Also accept const references when doing implicit conversions

This allows us to bind to temporaries.

Bug: none
Change-Id: Ic84ad378f344776bef38f9dc81a6fe0dee74400f
Reviewed-on: https://webrtc-review.googlesource.com/c/120901
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26530}

api/array_view.h

diff --git a/api/array_view.h b/api/array_view.h
index efc642d..bf91484 100644
--- a/api/array_view.h
+++ b/api/array_view.h
@@ -231,6 +231,12 @@
                               HasDataAndSize<U, T>::value>::type* = nullptr>
   ArrayView(U& u)  // NOLINT
       : ArrayView(u.data(), u.size()) {}
+  template <
+      typename U,
+      typename std::enable_if<Size == impl::kArrayViewVarSize &&
+                              HasDataAndSize<U, T>::value>::type* = nullptr>
+  ArrayView(const U& u)  // NOLINT(runtime/explicit)
+      : ArrayView(u.data(), u.size()) {}
 
   // Indexing and iteration. These allow mutation even if the ArrayView is
   // const, because the ArrayView doesn't own the array. (To prevent mutation,

api/array_view_unittest.cc

diff --git a/api/array_view_unittest.cc b/api/array_view_unittest.cc
index 694ed0b..62b51c0 100644
--- a/api/array_view_unittest.cc
+++ b/api/array_view_unittest.cc
@@ -28,16 +28,21 @@
 using ::testing::IsEmpty;
 
 template <typename T>
-void Call(ArrayView<T>) {}
+size_t Call(ArrayView<T> av) {
+  return av.size();
+}
+
+template <typename T, size_t N>
+void CallFixed(ArrayView<T, N> av) {}
 
 }  // namespace
 
 TEST(ArrayViewTest, TestConstructFromPtrAndArray) {
   char arr[] = "Arrr!";
   const char carr[] = "Carrr!";
-  Call<const char>(arr);
-  Call<const char>(carr);
-  Call<char>(arr);
+  EXPECT_EQ(6u, Call<const char>(arr));
+  EXPECT_EQ(7u, Call<const char>(carr));
+  EXPECT_EQ(6u, Call<char>(arr));
   // Call<char>(carr);  // Compile error, because can't drop const.
   // Call<int>(arr);  // Compile error, because incompatible types.
   ArrayView<int*> x;
@@ -182,6 +187,8 @@
 }
 
 TEST(ArrayViewTest, TestStdArray) {
+  EXPECT_EQ(4u, Call<const int>(std::array<int, 4>{1, 2, 3, 4}));
+  CallFixed<const int, 3>(std::array<int, 3>{2, 3, 4});
   constexpr size_t size = 5;
   std::array<float, size> arr{};
   // Fixed size view.
@@ -214,11 +221,12 @@
 }
 
 TEST(ArrayViewTest, TestStdVector) {
+  EXPECT_EQ(3u, Call<const int>(std::vector<int>{4, 5, 6}));
   std::vector<int> v;
   v.push_back(3);
   v.push_back(11);
-  Call<const int>(v);
-  Call<int>(v);
+  EXPECT_EQ(2u, Call<const int>(v));
+  EXPECT_EQ(2u, Call<int>(v));
   // Call<unsigned int>(v);  // Compile error, because incompatible types.
   ArrayView<int> x = v;
   EXPECT_EQ(2u, x.size());
@@ -229,7 +237,7 @@
   EXPECT_EQ(v.data(), y.data());
   // ArrayView<double> d = v;  // Compile error, because incompatible types.
   const std::vector<int> cv;
-  Call<const int>(cv);
+  EXPECT_EQ(0u, Call<const int>(cv));
   // Call<int>(cv);  // Compile error, because can't drop const.
   ArrayView<const int> z = cv;
   EXPECT_EQ(0u, z.size());
@@ -239,8 +247,8 @@
 
 TEST(ArrayViewTest, TestRtcBuffer) {
   rtc::Buffer b = "so buffer";
-  Call<const uint8_t>(b);
-  Call<uint8_t>(b);
+  EXPECT_EQ(10u, Call<const uint8_t>(b));
+  EXPECT_EQ(10u, Call<uint8_t>(b));
   // Call<int8_t>(b);  // Compile error, because incompatible types.
   ArrayView<uint8_t> x = b;
   EXPECT_EQ(10u, x.size());
@@ -251,7 +259,7 @@
   EXPECT_EQ(b.data(), y.data());
   // ArrayView<char> d = b;  // Compile error, because incompatible types.
   const rtc::Buffer cb = "very const";
-  Call<const uint8_t>(cb);
+  EXPECT_EQ(11u, Call<const uint8_t>(cb));
   // Call<uint8_t>(cb);  // Compile error, because can't drop const.
   ArrayView<const uint8_t> z = cb;
   EXPECT_EQ(11u, z.size());