ARROW-17875: [C++] Remove assorted pre-C++17 compatibility measures

cpp/src/arrow/result.h

@@ -420,11 +420,7 @@ class [[nodiscard]] Result : public util::EqualityComparable<Result<T>> {
 
   constexpr const T& ValueUnsafe() const& { return *storage_.get(); }
 
-#if __cpp_constexpr >= 201304L  // non-const constexpr
   constexpr T& ValueUnsafe() & { return *storage_.get(); }
-#else
-  T& ValueUnsafe() & { return *storage_.get(); }
-#endif
 
   T ValueUnsafe() && { return MoveValueUnsafe(); }
 

cpp/src/arrow/status.h

@@ -133,7 +133,7 @@ class ARROW_EXPORT [[nodiscard]] Status : public util::EqualityComparable<Status
                                           public util::ToStringOstreamable<Status> {
  public:
   // Create a success status.
-  Status() noexcept : state_(NULLPTR) {}
+  constexpr Status() noexcept : state_(NULLPTR) {}
   ~Status() noexcept {
     // ARROW-2400: On certain compilers, splitting off the slow path improves
     // performance significantly.
@@ -271,41 +271,43 @@ class ARROW_EXPORT [[nodiscard]] Status : public util::EqualityComparable<Status
   }
 
   /// Return true iff the status indicates success.
-  bool ok() const { return (state_ == NULLPTR); }
+  constexpr bool ok() const { return (state_ == NULLPTR); }
 
   /// Return true iff the status indicates an out-of-memory error.
-  bool IsOutOfMemory() const { return code() == StatusCode::OutOfMemory; }
+  constexpr bool IsOutOfMemory() const { return code() == StatusCode::OutOfMemory; }
   /// Return true iff the status indicates a key lookup error.
-  bool IsKeyError() const { return code() == StatusCode::KeyError; }
+  constexpr bool IsKeyError() const { return code() == StatusCode::KeyError; }
   /// Return true iff the status indicates invalid data.
-  bool IsInvalid() const { return code() == StatusCode::Invalid; }
+  constexpr bool IsInvalid() const { return code() == StatusCode::Invalid; }
   /// Return true iff the status indicates a cancelled operation.
-  bool IsCancelled() const { return code() == StatusCode::Cancelled; }
+  constexpr bool IsCancelled() const { return code() == StatusCode::Cancelled; }
   /// Return true iff the status indicates an IO-related failure.
-  bool IsIOError() const { return code() == StatusCode::IOError; }
+  constexpr bool IsIOError() const { return code() == StatusCode::IOError; }
   /// Return true iff the status indicates a container reaching capacity limits.
-  bool IsCapacityError() const { return code() == StatusCode::CapacityError; }
+  constexpr bool IsCapacityError() const { return code() == StatusCode::CapacityError; }
   /// Return true iff the status indicates an out of bounds index.
-  bool IsIndexError() const { return code() == StatusCode::IndexError; }
+  constexpr bool IsIndexError() const { return code() == StatusCode::IndexError; }
   /// Return true iff the status indicates a type error.
-  bool IsTypeError() const { return code() == StatusCode::TypeError; }
+  constexpr bool IsTypeError() const { return code() == StatusCode::TypeError; }
   /// Return true iff the status indicates an unknown error.
-  bool IsUnknownError() const { return code() == StatusCode::UnknownError; }
+  constexpr bool IsUnknownError() const { return code() == StatusCode::UnknownError; }
   /// Return true iff the status indicates an unimplemented operation.
-  bool IsNotImplemented() const { return code() == StatusCode::NotImplemented; }
+  constexpr bool IsNotImplemented() const { return code() == StatusCode::NotImplemented; }
   /// Return true iff the status indicates a (de)serialization failure
-  bool IsSerializationError() const { return code() == StatusCode::SerializationError; }
+  constexpr bool IsSerializationError() const {
+    return code() == StatusCode::SerializationError;
+  }
   /// Return true iff the status indicates a R-originated error.
-  bool IsRError() const { return code() == StatusCode::RError; }
+  constexpr bool IsRError() const { return code() == StatusCode::RError; }
 
-  bool IsCodeGenError() const { return code() == StatusCode::CodeGenError; }
+  constexpr bool IsCodeGenError() const { return code() == StatusCode::CodeGenError; }
 
-  bool IsExpressionValidationError() const {
+  constexpr bool IsExpressionValidationError() const {
     return code() == StatusCode::ExpressionValidationError;
   }
 
-  bool IsExecutionError() const { return code() == StatusCode::ExecutionError; }
-  bool IsAlreadyExists() const { return code() == StatusCode::AlreadyExists; }
+  constexpr bool IsExecutionError() const { return code() == StatusCode::ExecutionError; }
+  constexpr bool IsAlreadyExists() const { return code() == StatusCode::AlreadyExists; }
 
   /// \brief Return a string representation of this status suitable for printing.
   ///
@@ -318,7 +320,7 @@ class ARROW_EXPORT [[nodiscard]] Status : public util::EqualityComparable<Status
   static std::string CodeAsString(StatusCode);
 
   /// \brief Return the StatusCode value attached to this status.
-  StatusCode code() const { return ok() ? StatusCode::OK : state_->code; }
+  constexpr StatusCode code() const { return ok() ? StatusCode::OK : state_->code; }
 
   /// \brief Return the specific error message attached to this status.
   const std::string& message() const {

cpp/src/arrow/stl.h

@@ -20,7 +20,6 @@
 #include <algorithm>
 #include <cstddef>
 #include <memory>
-#include <sstream>
 #include <string>
 #include <tuple>
 #include <type_traits>
@@ -436,18 +435,15 @@ Status TupleRangeFromTable(const Table& table, const compute::CastOptions& cast_
   constexpr std::size_t n_columns = std::tuple_size<row_type>::value;
 
   if (table.schema()->num_fields() != n_columns) {
-    std::stringstream ss;
-    ss << "Number of columns in the table does not match the width of the target: ";
-    ss << table.schema()->num_fields() << " != " << n_columns;
-    return Status::Invalid(ss.str());
+    return Status::Invalid(
+        "Number of columns in the table does not match the width of the target: ",
+        table.schema()->num_fields(), " != ", n_columns);
   }
 
-  // TODO: Use std::size with C++17
-  if (rows->size() != static_cast<size_t>(table.num_rows())) {
-    std::stringstream ss;
-    ss << "Number of rows in the table does not match the size of the target: ";
-    ss << table.num_rows() << " != " << rows->size();
-    return Status::Invalid(ss.str());
+  if (std::size(*rows) != static_cast<size_t>(table.num_rows())) {
+    return Status::Invalid(
+        "Number of rows in the table does not match the size of the target: ",
+        table.num_rows(), " != ", std::size(*rows));
   }
 
   // Check that all columns have the correct type, otherwise cast them.

cpp/src/arrow/util/aligned_storage.h

@@ -32,13 +32,9 @@ class AlignedStorage {
  public:
   static constexpr bool can_memcpy = std::is_trivial<T>::value;
 
-#if __cpp_constexpr >= 201304L  // non-const constexpr
   constexpr T* get() noexcept {
     return arrow::internal::launder(reinterpret_cast<T*>(&data_));
   }
-#else
-  T* get() noexcept { return arrow::internal::launder(reinterpret_cast<T*>(&data_)); }
-#endif
 
   constexpr const T* get() const noexcept {
     // Use fully qualified name to avoid ambiguities with MSVC (ARROW-14800)

cpp/src/arrow/util/macros.h

@@ -89,33 +89,14 @@
 // This macro takes an optional deprecation message
 #ifdef __COVERITY__
 #  define ARROW_DEPRECATED(...)
-#  define ARROW_DEPRECATED_USING(...)
-#elif __cplusplus > 201103L
-#  define ARROW_DEPRECATED(...) [[deprecated(__VA_ARGS__)]]
-#  define ARROW_DEPRECATED_USING(...) ARROW_DEPRECATED(__VA_ARGS__)
 #else
-# ifdef __GNUC__
-#  define ARROW_DEPRECATED(...) __attribute__((deprecated(__VA_ARGS__)))
-#  define ARROW_DEPRECATED_USING(...) ARROW_DEPRECATED(__VA_ARGS__)
-# elif defined(_MSC_VER)
-#  define ARROW_DEPRECATED(...) __declspec(deprecated(__VA_ARGS__))
-#  define ARROW_DEPRECATED_USING(...)
-# else
-#  define ARROW_DEPRECATED(...)
-#  define ARROW_DEPRECATED_USING(...)
-# endif
+#  define ARROW_DEPRECATED(...) [[deprecated(__VA_ARGS__)]]
 #endif
 
 #ifdef __COVERITY__
 #  define ARROW_DEPRECATED_ENUM_VALUE(...)
-#elif __cplusplus > 201103L
-#  define ARROW_DEPRECATED_ENUM_VALUE(...) [[deprecated(__VA_ARGS__)]]
 #else
-# if defined(__GNUC__) && __GNUC__ >= 6
-#  define ARROW_DEPRECATED_ENUM_VALUE(...) __attribute__((deprecated(__VA_ARGS__)))
-# else
-#  define ARROW_DEPRECATED_ENUM_VALUE(...)
-# endif
+#  define ARROW_DEPRECATED_ENUM_VALUE(...) [[deprecated(__VA_ARGS__)]]
 #endif
 
 // clang-format on

cpp/src/arrow/util/small_vector.h

@@ -65,11 +65,7 @@ struct StaticVectorStorage : public StaticVectorStorageBase<T, N, D> {
 
   StaticVectorStorage() noexcept = default;
 
-#if __cpp_constexpr >= 201304L  // non-const constexpr
   constexpr storage_type* storage_ptr() { return static_data_; }
-#else
-  storage_type* storage_ptr() { return static_data_; }
-#endif
 
   constexpr const storage_type* const_storage_ptr() const { return static_data_; }
 
@@ -124,11 +120,7 @@ struct SmallVectorStorage {
 
   ~SmallVectorStorage() { destroy(); }
 
-#if __cpp_constexpr >= 201304L  // non-const constexpr
   constexpr storage_type* storage_ptr() { return data_; }
-#else
-  storage_type* storage_ptr() { return data_; }
-#endif
 
   constexpr const storage_type* const_storage_ptr() const { return data_; }