[Impeller] Make storage sizes typed. (#53700)

This is similar to our handling of degrees and radians or really any of the stuff in chrono.

Storage is always in bytes. Before being displayed, it can be converted into any of unit that makes the most sense. Conversions are non-truncating and everything is constexpr safe.

Author: chinmaygarde

ci/licenses_golden/excluded_files

@@ -133,6 +133,7 @@
 ../../../flutter/impeller/aiks/canvas_unittests.cc
 ../../../flutter/impeller/aiks/testing
 ../../../flutter/impeller/base/README.md
+../../../flutter/impeller/base/allocation_size_unittests.cc
 ../../../flutter/impeller/base/base_unittests.cc
 ../../../flutter/impeller/compiler/README.md
 ../../../flutter/impeller/compiler/compiler_unittests.cc

ci/licenses_golden/licenses_flutter

@@ -41853,6 +41853,8 @@ ORIGIN: ../../../flutter/impeller/aiks/picture_recorder.cc + ../../../flutter/LI
 ORIGIN: ../../../flutter/impeller/aiks/picture_recorder.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/base/allocation.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/base/allocation.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/base/allocation_size.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/base/allocation_size.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/base/backend_cast.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/base/comparable.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/base/comparable.h + ../../../flutter/LICENSE
@@ -44717,6 +44719,8 @@ FILE: ../../../flutter/impeller/aiks/picture_recorder.cc
 FILE: ../../../flutter/impeller/aiks/picture_recorder.h
 FILE: ../../../flutter/impeller/base/allocation.cc
 FILE: ../../../flutter/impeller/base/allocation.h
+FILE: ../../../flutter/impeller/base/allocation_size.cc
+FILE: ../../../flutter/impeller/base/allocation_size.h
 FILE: ../../../flutter/impeller/base/backend_cast.h
 FILE: ../../../flutter/impeller/base/comparable.cc
 FILE: ../../../flutter/impeller/base/comparable.h

impeller/base/BUILD.gn

@@ -8,6 +8,8 @@ impeller_component("base") {
   sources = [
     "allocation.cc",
     "allocation.h",
+    "allocation_size.cc",
+    "allocation_size.h",
     "backend_cast.h",
     "comparable.cc",
     "comparable.h",
@@ -33,7 +35,10 @@ impeller_component("base") {
 
 impeller_component("base_unittests") {
   testonly = true
-  sources = [ "base_unittests.cc" ]
+  sources = [
+    "allocation_size_unittests.cc",
+    "base_unittests.cc",
+  ]
   deps = [
     ":base",
     "//flutter/testing",

impeller/base/allocation.h

@@ -9,6 +9,7 @@
 #include <memory>
 
 #include "flutter/fml/mapping.h"
+#include "impeller/base/allocation_size.h"
 
 namespace impeller {
 

impeller/base/allocation_size.cc

@@ -0,0 +1,11 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "impeller/base/allocation_size.h"
+
+namespace impeller {
+
+//
+
+}  // namespace impeller

impeller/base/allocation_size.h

@@ -0,0 +1,198 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_IMPELLER_BASE_ALLOCATION_SIZE_H_
+#define FLUTTER_IMPELLER_BASE_ALLOCATION_SIZE_H_
+
+#include <cstddef>
+#include <cstdint>
+
+namespace impeller {
+
+enum class FromBytesTag { kFromBytes };
+
+//------------------------------------------------------------------------------
+/// @brief      Represents the size of an allocation in different units.
+///
+///             Refer to the typedefs for Bytes, KiloBytes, MegaBytes,
+///             Gigabytes, KibiBytes, MebiBytes, and GibiBytes below when using.
+///
+///             Storage and all operations are always on unsigned units of
+///             bytes.
+///
+/// @tparam     Period   The number of bytes in 1 unit of the allocation size.
+///
+template <size_t Period>
+class AllocationSize {
+ public:
+  //----------------------------------------------------------------------------
+  /// @brief      Create a zero allocation size.
+  ///
+  constexpr AllocationSize() = default;
+
+  //----------------------------------------------------------------------------
+  /// @brief      Create an allocation size with the amount in the `Period`
+  ///             number of bytes.
+  ///
+  /// @param[in]  size  The size in `Period` number of bytes.
+  ///
+  explicit constexpr AllocationSize(double size) : bytes_(size * Period) {}
+
+  //----------------------------------------------------------------------------
+  /// @brief      Create an allocation size from another instance with a
+  ///             different period.
+  ///
+  /// @param[in]  other        The other allocation size.
+  ///
+  /// @tparam     OtherPeriod  The period of the other allocation.
+  ///
+  template <size_t OtherPeriod>
+  explicit constexpr AllocationSize(const AllocationSize<OtherPeriod>& other)
+      : bytes_(other.GetByteSize()) {}
+
+  //----------------------------------------------------------------------------
+  /// @brief      Create an allocation size with the amount directly specified
+  ///             in bytes.
+  ///
+  /// @param[in]  byte_size  The byte size.
+  /// @param[in]  tag        A tag for this constructor.
+  ///
+  constexpr AllocationSize(uint64_t byte_size, FromBytesTag)
+      : bytes_(byte_size) {}
+
+  //----------------------------------------------------------------------------
+  /// @return     The byte size.
+  ///
+  constexpr uint64_t GetByteSize() const { return bytes_; }
+
+  //----------------------------------------------------------------------------
+  /// @return     The number of `Periods` of bytes.
+  ///
+  constexpr double GetSize() const {
+    return GetByteSize() / static_cast<double>(Period);
+  }
+
+  //----------------------------------------------------------------------------
+  /// @brief      Convert the allocation size from one unit to another.
+  ///
+  ///             Conversions are non-truncating.
+  ///
+  /// @tparam     AllocationSize  The allocation size to convert to.
+  ///
+  /// @return     The new allocation size.
+  ///
+  template <class AllocationSize>
+  constexpr AllocationSize ConvertTo() {
+    return AllocationSize{GetByteSize(), FromBytesTag::kFromBytes};
+  }
+
+  // The following relational operators can be replaced with a defaulted
+  // spaceship operator post C++20.
+
+  constexpr bool operator<(const AllocationSize& other) const {
+    return bytes_ < other.bytes_;
+  }
+
+  constexpr bool operator>(const AllocationSize& other) const {
+    return bytes_ > other.bytes_;
+  }
+
+  constexpr bool operator>=(const AllocationSize& other) const {
+    return bytes_ >= other.bytes_;
+  }
+
+  constexpr bool operator<=(const AllocationSize& other) const {
+    return bytes_ <= other.bytes_;
+  }
+
+  constexpr bool operator==(const AllocationSize& other) const {
+    return bytes_ == other.bytes_;
+  }
+
+  constexpr bool operator!=(const AllocationSize& other) const {
+    return bytes_ != other.bytes_;
+  }
+
+  // Explicit casts.
+
+  explicit constexpr operator bool() const { return bytes_ != 0u; }
+
+  // Arithmetic operators (overflows are caller error).
+
+  constexpr AllocationSize operator+(const AllocationSize& other) const {
+    return AllocationSize(bytes_ + other.GetByteSize(),
+                          FromBytesTag::kFromBytes);
+  }
+
+  constexpr AllocationSize operator-(const AllocationSize& other) const {
+    return AllocationSize(bytes_ - other.GetByteSize(),
+                          FromBytesTag::kFromBytes);
+  }
+
+  constexpr AllocationSize& operator+=(const AllocationSize& other) {
+    bytes_ += other.GetByteSize();
+    return *this;
+  }
+
+  constexpr AllocationSize& operator-=(const AllocationSize& other) {
+    bytes_ -= other.GetByteSize();
+    return *this;
+  }
+
+ private:
+  uint64_t bytes_ = {};
+};
+
+using Bytes = AllocationSize<1u>;
+
+using KiloBytes = AllocationSize<1'000u>;
+using MegaBytes = AllocationSize<1'000u * 1'000u>;
+using GigaBytes = AllocationSize<1'000u * 1'000u * 1'000u>;
+
+using KibiBytes = AllocationSize<1'024u>;
+using MebiBytes = AllocationSize<1'024u * 1'024u>;
+using GibiBytes = AllocationSize<1'024u * 1'024u * 1'024u>;
+
+inline namespace allocation_size_literals {
+
+// NOLINTNEXTLINE
+constexpr Bytes operator"" _bytes(unsigned long long int size) {
+  return Bytes{static_cast<double>(size)};
+}
+
+// NOLINTNEXTLINE
+constexpr KiloBytes operator"" _kb(unsigned long long int size) {
+  return KiloBytes{static_cast<double>(size)};
+}
+
+// NOLINTNEXTLINE
+constexpr MegaBytes operator"" _mb(unsigned long long int size) {
+  return MegaBytes{static_cast<double>(size)};
+}
+
+// NOLINTNEXTLINE
+constexpr GigaBytes operator"" _gb(unsigned long long int size) {
+  return GigaBytes{static_cast<double>(size)};
+}
+
+// NOLINTNEXTLINE
+constexpr KibiBytes operator"" _kib(unsigned long long int size) {
+  return KibiBytes{static_cast<double>(size)};
+}
+
+// NOLINTNEXTLINE
+constexpr MebiBytes operator"" _mib(unsigned long long int size) {
+  return MebiBytes{static_cast<double>(size)};
+}
+
+// NOLINTNEXTLINE
+constexpr GibiBytes operator"" _gib(unsigned long long int size) {
+  return GibiBytes{static_cast<double>(size)};
+}
+
+}  // namespace allocation_size_literals
+
+}  // namespace impeller
+
+#endif  // FLUTTER_IMPELLER_BASE_ALLOCATION_SIZE_H_

impeller/base/allocation_size_unittests.cc

@@ -0,0 +1,110 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/testing/testing.h"
+#include "impeller/base/allocation_size.h"
+
+namespace impeller::testing {
+
+TEST(AllocationSizeTest, CanCreateTypedAllocations) {
+  auto bytes = Bytes{1024};
+  ASSERT_EQ(bytes.GetByteSize(), 1024u);
+
+  auto kilobytes = KiloBytes{5};
+  ASSERT_EQ(kilobytes.GetByteSize(), 5u * 1e3);
+
+  auto megabytes = MegaBytes{5};
+  ASSERT_EQ(megabytes.GetByteSize(), 5u * 1e6);
+
+  auto gigabytes = GigaBytes{5};
+  ASSERT_EQ(gigabytes.GetByteSize(), 5u * 1e9);
+
+  auto kibibytes = KibiBytes{1};
+  ASSERT_EQ(kibibytes.GetByteSize(), 1024u);
+
+  auto mebibytes = MebiBytes{1};
+  ASSERT_EQ(mebibytes.GetByteSize(), 1048576u);
+
+  auto gigibytes = GibiBytes{1};
+  ASSERT_EQ(gigibytes.GetByteSize(), 1073741824u);
+}
+
+TEST(AllocationSizeTest, CanCreateTypedAllocationsWithLiterals) {
+  using namespace allocation_size_literals;
+  ASSERT_EQ((1024_bytes).GetByteSize(), 1024u);
+  ASSERT_EQ((5_kb).GetByteSize(), 5u * 1e3);
+  ASSERT_EQ((5_mb).GetByteSize(), 5u * 1e6);
+  ASSERT_EQ((5_gb).GetByteSize(), 5u * 1e9);
+  ASSERT_EQ((1_kib).GetByteSize(), 1024u);
+  ASSERT_EQ((1_mib).GetByteSize(), 1048576u);
+  ASSERT_EQ((1_gib).GetByteSize(), 1073741824u);
+}
+
+TEST(AllocationSizeTest, CanConvert) {
+  using namespace allocation_size_literals;
+  ASSERT_EQ((5_gb).ConvertTo<MegaBytes>().GetSize(), 5000u);
+}
+
+TEST(AllocationSizeTest, ConversionsAreNonTruncating) {
+  using namespace allocation_size_literals;
+  ASSERT_DOUBLE_EQ((1500_bytes).ConvertTo<KiloBytes>().GetSize(), 1.5);
+  ASSERT_EQ((1500_bytes).ConvertTo<KiloBytes>().GetByteSize(), 1500u);
+}
+
+TEST(AllocationSizeTest, CanGetFloatValues) {
+  using namespace allocation_size_literals;
+  ASSERT_DOUBLE_EQ((1500_bytes).ConvertTo<KiloBytes>().GetSize(), 1.5);
+}
+
+TEST(AllocationSizeTest, RelationalOperatorsAreFunctional) {
+  using namespace allocation_size_literals;
+
+  auto a = 1500_bytes;
+  auto b = 2500_bytes;
+  auto c = 0_bytes;
+
+  ASSERT_TRUE(a != b);
+  ASSERT_FALSE(a == b);
+  ASSERT_TRUE(b > a);
+  ASSERT_TRUE(b >= a);
+  ASSERT_TRUE(a < b);
+  ASSERT_TRUE(a <= b);
+  ASSERT_TRUE(a);
+  ASSERT_FALSE(c);
+}
+
+TEST(AllocationSizeTest, CanCast) {
+  using namespace allocation_size_literals;
+  {
+    auto a = KiloBytes{1500_bytes};
+    ASSERT_DOUBLE_EQ(a.GetSize(), 1.5);
+  }
+  {
+    auto a = KiloBytes{Bytes{1500}};
+    ASSERT_DOUBLE_EQ(a.GetSize(), 1.5);
+  }
+
+  ASSERT_DOUBLE_EQ(MebiBytes{Bytes{4194304}}.GetSize(), 4);
+}
+
+TEST(AllocationSizeTest, CanPerformSimpleArithmetic) {
+  using namespace allocation_size_literals;
+  {
+    auto a = 100_bytes;
+    auto b = 200_bytes;
+    ASSERT_EQ((a + b).GetByteSize(), 300u);
+  }
+  {
+    auto a = 100_bytes;
+    a += 200_bytes;
+    ASSERT_EQ(a.GetByteSize(), 300u);
+  }
+  {
+    auto a = 100_bytes;
+    a -= 50_bytes;
+    ASSERT_EQ(a.GetByteSize(), 50u);
+  }
+}
+
+}  // namespace impeller::testing

impeller/core/allocator.h

@@ -6,6 +6,7 @@
 #define FLUTTER_IMPELLER_CORE_ALLOCATOR_H_
 
 #include "flutter/fml/mapping.h"
+#include "impeller/base/allocation_size.h"
 #include "impeller/core/device_buffer_descriptor.h"
 #include "impeller/core/texture.h"
 #include "impeller/core/texture_descriptor.h"
@@ -51,7 +52,7 @@ class Allocator {
   virtual void DebugTraceMemoryStatistics() const {};
 
   // Visible for testing.
-  virtual size_t DebugGetHeapUsage() const { return 0; }
+  virtual Bytes DebugGetHeapUsage() const { return Bytes{0}; }
 
  protected:
   Allocator();