[fastapi] Stop using deprecated FastApiTypedArray (#202)

* [fastapi] Stop using deprecated FastApiTypedArray

* [fastapi] Stop using deprecated FastApiTypedArray

This PR changes the signature of `FastCopy` and `WriteString` to not use
`FastApiTypedArray` anymore. Instead the buffer is received as
`Local<Value>`, and the type check is done in node instead of generated
code.

The data of the buffers is extracted the same as for slow calls. For the
source of `FastCopy` it would also be possible to use the new V8 API
`ArrayBufferView::GetContents()`, but I thought it's better for now to
remain close to the regular implementation. For the other buffers this
API cannot be used because it does not provide write access to the data,
as it copies the data if it's stored on the heap.

src/node_buffer.cc

@@ -42,7 +42,15 @@
 #include "nbytes.h"
 
 #define THROW_AND_RETURN_UNLESS_BUFFER(env, obj)                            \
-  THROW_AND_RETURN_IF_NOT_BUFFER(env, obj, "argument")                      \
+  THROW_AND_RETURN_IF_NOT_BUFFER(env, obj, "argument")
+
+#define THROW_AND_RETURN_VAL_UNLESS_BUFFER(isolate, val, prefix, retval)       \
+  do {                                                                         \
+    if (!Buffer::HasInstance(val)) {                                           \
+      node::THROW_ERR_INVALID_ARG_TYPE(isolate, prefix " must be a buffer");   \
+      return retval;                                                           \
+    }                                                                          \
+  } while (0)
 
 #define THROW_AND_RETURN_IF_OOB(r)                                          \
   do {                                                                      \
@@ -60,7 +68,6 @@ using v8::ArrayBufferView;
 using v8::BackingStore;
 using v8::Context;
 using v8::EscapableHandleScope;
-using v8::FastApiTypedArray;
 using v8::FunctionCallbackInfo;
 using v8::Global;
 using v8::HandleScope;
@@ -582,19 +589,17 @@ void SlowCopy(const FunctionCallbackInfo<Value>& args) {
 
 // Assume caller has properly validated args.
 uint32_t FastCopy(Local<Value> receiver,
-                  const v8::FastApiTypedArray<uint8_t>& source,
-                  const v8::FastApiTypedArray<uint8_t>& target,
+                  Local<Value> source_obj,
+                  Local<Value> target_obj,
                   uint32_t target_start,
                   uint32_t source_start,
-                  uint32_t to_copy) {
-  uint8_t* source_data;
-  CHECK(source.getStorageIfAligned(&source_data));
-
-  uint8_t* target_data;
-  CHECK(target.getStorageIfAligned(&target_data));
-
-  memmove(target_data + target_start, source_data + source_start, to_copy);
+                  uint32_t to_copy,
+                  // NOLINTNEXTLINE(runtime/references) This is V8 api.
+                  v8::FastApiCallbackOptions& options) {
+  ArrayBufferViewContents<char> source(source_obj);
+  SPREAD_BUFFER_ARG(target_obj, target);
 
+  memmove(target_data + target_start, source.data() + source_start, to_copy);
   return to_copy;
 }
 
@@ -1469,21 +1474,25 @@ void SlowWriteString(const FunctionCallbackInfo<Value>& args) {
 
 template <encoding encoding>
 uint32_t FastWriteString(Local<Value> receiver,
-                         const v8::FastApiTypedArray<uint8_t>& dst,
+                         Local<Value> dst,
                          const v8::FastOneByteString& src,
                          uint32_t offset,
-                         uint32_t max_length) {
-  uint8_t* dst_data;
-  CHECK(dst.getStorageIfAligned(&dst_data));
-  CHECK(offset <= dst.length());
-  CHECK(dst.length() - offset <= std::numeric_limits<uint32_t>::max());
+                         uint32_t max_length,
+                         // NOLINTNEXTLINE(runtime/references) This is V8 api.
+                         v8::FastApiCallbackOptions& options) {
+  THROW_AND_RETURN_VAL_UNLESS_BUFFER(options.isolate, dst, "dst", 0);
+  SPREAD_BUFFER_ARG(dst, dst_buffer);
+  CHECK(dst_buffer_length <=
+        static_cast<size_t>(std::numeric_limits<uint32_t>::max()));
+  uint32_t dst_size = static_cast<uint32_t>(dst_buffer_length);
+  CHECK(offset <= dst_size);
   TRACK_V8_FAST_API_CALL("buffer.writeString");
 
   return WriteOneByteString<encoding>(
       src.data,
       src.length,
-      reinterpret_cast<char*>(dst_data + offset),
-      std::min<uint32_t>(dst.length() - offset, max_length));
+      reinterpret_cast<char*>(dst_buffer_data + offset),
+      std::min<uint32_t>(dst_size - offset, max_length));
 }
 
 static v8::CFunction fast_write_string_ascii(

src/node_external_reference.h

@@ -53,18 +53,20 @@ using CFunctionWithBool = void (*)(v8::Local<v8::Value>,
 
 using CFunctionWriteString =
     uint32_t (*)(v8::Local<v8::Value> receiver,
-                 const v8::FastApiTypedArray<uint8_t>& dst,
+                 v8::Local<v8::Value> dst,
                  const v8::FastOneByteString& src,
                  uint32_t offset,
-                 uint32_t max_length);
+                 uint32_t max_length,
+                 v8::FastApiCallbackOptions&);
 
 using CFunctionBufferCopy =
     uint32_t (*)(v8::Local<v8::Value> receiver,
-                 const v8::FastApiTypedArray<uint8_t>& source,
-                 const v8::FastApiTypedArray<uint8_t>& target,
+                 v8::Local<v8::Value> source,
+                 v8::Local<v8::Value> target,
                  uint32_t target_start,
                  uint32_t source_start,
-                 uint32_t to_copy);
+                 uint32_t to_copy,
+                 v8::FastApiCallbackOptions&);
 
 // This class manages the external references from the V8 heap
 // to the C++ addresses in Node.js.