src: enable DataView feature by default

This patch contains the following things:
  - Add a document for `DataView` feature
  - Remove NAPI_DATA_VIEW_FEATURE

Refs: nodejs/node-addon-api#196

PR-URL: nodejs/node-addon-api#331
Refs: nodejs/node-addon-api#196
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Nicola Del Gobbo <nicoladelgobbo@NickNaso.local>

README.md

@@ -97,6 +97,7 @@ still a work in progress as its not yet complete).
     - [ArrayBuffer](doc/array_buffer.md)
     - [TypedArray](doc/typed_array.md)
       - [TypedArrayOf](doc/typed_array_of.md)
+    - [DataView](doc/dataview.md)
  - [Memory Management](doc/memory_management.md)
  - [Async Operations](doc/async_operations.md)
     - [AsyncWorker](doc/async_worker.md)

doc/dataview.md

@@ -0,0 +1,244 @@
+# DataView
+
+The `Napi::DataView` class corresponds to the
+[JavaScript `DataView`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView)
+class.
+
+## Methods
+
+### New
+
+Allocates a new `Napi::DataView` instance with a given `Napi::ArrayBuffer`.
+
+```cpp
+static Napi::DataView New(napi_env env, Napi::ArrayBuffer arrayBuffer);
+```
+
+- `[in] env`: The environment in which to create the `Napi::DataView` instance.
+- `[in] arrayBuffer` : `Napi::ArrayBuffer` underlying the `Napi::DataView`.
+
+Returns a new `Napi::DataView` instance.
+
+### New
+
+Allocates a new `Napi::DataView` instance with a given `Napi::ArrayBuffer`.
+
+```cpp
+static Napi::DataView New(napi_env env, Napi::ArrayBuffer arrayBuffer, size_t byteOffset);
+```
+
+- `[in] env`: The environment in which to create the `Napi::DataView` instance.
+- `[in] arrayBuffer` : `Napi::ArrayBuffer` underlying the `Napi::DataView`.
+- `[in] byteOffset` : The byte offset within the `Napi::ArrayBuffer` from which to start projecting the `Napi::DataView`.
+
+Returns a new `Napi::DataView` instance.
+
+### New
+
+Allocates a new `Napi::DataView` instance with a given `Napi::ArrayBuffer`.
+
+```cpp
+static Napi::DataView New(napi_env env, Napi::ArrayBuffer arrayBuffer, size_t byteOffset, size_t byteLength);
+```
+
+- `[in] env`: The environment in which to create the `Napi::DataView` instance.
+- `[in] arrayBuffer` : `Napi::ArrayBuffer` underlying the `Napi::DataView`.
+- `[in] byteOffset` : The byte offset within the `Napi::ArrayBuffer` from which to start projecting the `Napi::DataView`.
+- `[in] byteLength` : Number of elements in the `Napi::DataView`.
+
+Returns a new `Napi::DataView` instance.
+
+### Constructor
+
+Initializes an empty instance of the `Napi::DataView` class.
+
+```cpp
+DataView();
+```
+
+### Constructor
+
+Initializes a wrapper instance of an existing `Napi::DataView` instance.
+
+```cpp
+DataView(napi_env env, napi_value value);
+```
+
+- `[in] env`: The environment in which to create the `Napi::DataView` instance.
+- `[in] value`: The `Napi::DataView` reference to wrap.
+
+### ArrayBuffer
+
+```cpp
+Napi::ArrayBuffer ArrayBuffer() const;
+```
+
+Returns the backing array buffer.
+
+### ByteOffset
+
+```cpp
+size_t ByteOffset() const;
+```
+
+Returns the offset into the `Napi::DataView` where the array starts, in bytes.
+
+### ByteLength
+
+```cpp
+size_t ByteLength() const;
+```
+
+Returns the length of the array, in bytes.
+
+### GetFloat32
+
+```cpp
+float GetFloat32(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a signed 32-bit float (float) at the specified byte offset from the start of the `DataView`.
+
+### GetFloat64
+
+```cpp
+double GetFloat64(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a signed 64-bit float (double) at the specified byte offset from the start of the `Napi::DataView`.
+
+### GetInt8
+
+```cpp
+int8_t GetInt8(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a signed 8-bit integer (byte) at the specified byte offset from the start of the `Napi::DataView`.
+
+### GetInt16
+
+```cpp
+int16_t GetInt16(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a signed 16-bit integer (short) at the specified byte offset from the start of the `Napi::DataView`.
+
+### GetInt32
+
+```cpp
+int32_t GetInt32(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a signed 32-bit integer (long) at the specified byte offset from the start of the `Napi::DataView`.
+
+### GetUint8
+
+```cpp
+uint8_t GetUint8(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a unsigned 8-bit integer (unsigned byte) at the specified byte offset from the start of the `Napi::DataView`.
+
+### GetUint16
+
+```cpp
+uint16_t GetUint16(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a unsigned 16-bit integer (unsigned short) at the specified byte offset from the start of the `Napi::DataView`.
+
+### GetUint32
+
+```cpp
+uint32_t GetUint32(size_t byteOffset) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+
+Returns a unsigned 32-bit integer (unsigned long) at the specified byte offset from the start of the `Napi::DataView`.
+
+### SetFloat32
+
+```cpp
+void SetFloat32(size_t byteOffset, float value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetFloat64
+
+```cpp
+void SetFloat64(size_t byteOffset, double value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetInt8
+
+```cpp
+void SetInt8(size_t byteOffset, int8_t value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetInt16
+
+```cpp
+void SetInt16(size_t byteOffset, int16_t value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetInt32
+
+```cpp
+void SetInt32(size_t byteOffset, int32_t value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetUint8
+
+```cpp
+void SetUint8(size_t byteOffset, uint8_t value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetUint16
+
+```cpp
+void SetUint16(size_t byteOffset, uint16_t value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.
+
+### SetUint32
+
+```cpp
+void SetUint32(size_t byteOffset, uint32_t value) const;
+```
+
+- `[in] byteOffset`: The offset, in byte, from the start of the view where to read the data.
+- `[in] value`: The value to set.

napi-inl.h

@@ -364,7 +364,6 @@ inline bool Value::IsPromise() const {
   return result;
 }
 
-#if NAPI_DATA_VIEW_FEATURE
 inline bool Value::IsDataView() const {
   if (_value == nullptr) {
     return false;
@@ -375,7 +374,6 @@ inline bool Value::IsDataView() const {
   NAPI_THROW_IF_FAILED(_env, status, false);
   return result;
 }
-#endif
 
 inline bool Value::IsBuffer() const {
   if (_value == nullptr) {
@@ -1255,7 +1253,6 @@ inline void ArrayBuffer::EnsureInfo() const {
   }
 }
 
-#if NAPI_DATA_VIEW_FEATURE
 ////////////////////////////////////////////////////////////////////////////////
 // DataView class
 ////////////////////////////////////////////////////////////////////////////////
@@ -1426,7 +1423,6 @@ inline void DataView::WriteData(size_t byteOffset, T value) const {
 
   *reinterpret_cast<T*>(static_cast<uint8_t*>(_data) + byteOffset) = value;
 }
-#endif
 
 ////////////////////////////////////////////////////////////////////////////////
 // TypedArray class

napi.h

@@ -189,9 +189,7 @@ namespace Napi {
     bool IsObject() const;      ///< Tests if a value is a JavaScript object.
     bool IsFunction() const;    ///< Tests if a value is a JavaScript function.
     bool IsPromise() const;     ///< Tests if a value is a JavaScript promise.
-#if NAPI_DATA_VIEW_FEATURE
     bool IsDataView() const;    ///< Tests if a value is a JavaScript data view.
-#endif
     bool IsBuffer() const;      ///< Tests if a value is a Node buffer.
     bool IsExternal() const;    ///< Tests if a value is a pointer to external data.
 
@@ -836,7 +834,6 @@ namespace Napi {
                  T* data);
   };
 
-#if NAPI_DATA_VIEW_FEATURE
   /// The DataView provides a low-level interface for reading/writing multiple
   /// number types in an ArrayBuffer irrespective of the platform's endianness.
   class DataView : public Object {
@@ -888,7 +885,6 @@ namespace Napi {
     void* _data;
     size_t _length;
   };
-#endif
 
   class Function : public Object {
   public:

test/binding.gyp

@@ -37,7 +37,7 @@
   'targets': [
     {
       'target_name': 'binding',
-      'defines': [ 'NAPI_CPP_EXCEPTIONS', 'NAPI_DATA_VIEW_FEATURE' ],
+      'defines': [ 'NAPI_CPP_EXCEPTIONS' ],
       'cflags!': [ '-fno-exceptions' ],
       'cflags_cc!': [ '-fno-exceptions' ],
       'msvs_settings': {
@@ -54,7 +54,7 @@
     },
     {
       'target_name': 'binding_noexcept',
-      'defines': [ 'NAPI_DISABLE_CPP_EXCEPTIONS', 'NAPI_DATA_VIEW_FEATURE' ],
+      'defines': [ 'NAPI_DISABLE_CPP_EXCEPTIONS' ],
       'cflags': [ '-fno-exceptions' ],
       'cflags_cc': [ '-fno-exceptions' ],
       'msvs_settings': {