Implement RawValue type (alternative)

Cargo.toml

@@ -26,6 +26,12 @@ compiletest_rs = "0.3"
 serde_bytes = "0.10"
 serde_derive = "1.0"
 
+[package.metadata.docs.rs]
+features = ["raw_value"]
+
+[package.metadata.playground]
+features = ["raw_value"]
+
 
 ### FEATURES #################################################################
 
@@ -41,3 +47,6 @@ preserve_order = ["indexmap"]
 # allows JSON numbers of arbitrary size/precision to be read into a Number and
 # written back to a JSON string without loss of precision.
 arbitrary_precision = []
+
+# Provide a RawValue type that can hold unprocessed JSON during deserialization.
+raw_value = []

src/de.rs

@@ -946,6 +946,17 @@ impl<'de, R: Read<'de>> Deserializer<R> {
             }
         }
     }
+
+    #[cfg(feature = "raw_value")]
+    fn deserialize_raw_value<V>(&mut self, visitor: V) -> Result<V::Value>
+    where
+        V: de::Visitor<'de>,
+    {
+        self.parse_whitespace()?;
+        self.read.begin_raw_buffering();
+        self.ignore_value()?;
+        self.read.end_raw_buffering(visitor)
+    }
 }
 
 impl FromStr for Number {
@@ -1412,10 +1423,18 @@ impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
 
     /// Parses a newtype struct as the underlying value.
     #[inline]
-    fn deserialize_newtype_struct<V>(self, _name: &str, visitor: V) -> Result<V::Value>
+    fn deserialize_newtype_struct<V>(self, name: &str, visitor: V) -> Result<V::Value>
     where
         V: de::Visitor<'de>,
     {
+        #[cfg(feature = "raw_value")]
+        {
+            if name == ::raw::TOKEN {
+                return self.deserialize_raw_value(visitor);
+            }
+        }
+
+        let _ = name;
         visitor.visit_newtype_struct(self)
     }
 

src/lib.rs

@@ -389,3 +389,6 @@ pub mod value;
 mod iter;
 mod number;
 mod read;
+
+#[cfg(feature = "raw_value")]
+mod raw;

src/number.rs

@@ -26,12 +26,7 @@ use error::ErrorCode;
 #[cfg(feature = "arbitrary_precision")]
 /// Not public API. Should be pub(crate).
 #[doc(hidden)]
-pub const SERDE_STRUCT_FIELD_NAME: &'static str = "$__serde_private_number";
-
-#[cfg(feature = "arbitrary_precision")]
-/// Not public API. Should be pub(crate).
-#[doc(hidden)]
-pub const SERDE_STRUCT_NAME: &'static str = "$__serde_private_Number";
+pub const TOKEN: &'static str = "$serde_json::private::Number";
 
 /// Represents a JSON number, whether integer or floating point.
 #[derive(Clone, PartialEq)]
@@ -346,8 +341,8 @@ impl Serialize for Number {
     {
         use serde::ser::SerializeStruct;
 
-        let mut s = serializer.serialize_struct(SERDE_STRUCT_NAME, 1)?;
-        s.serialize_field(SERDE_STRUCT_FIELD_NAME, &self.n)?;
+        let mut s = serializer.serialize_struct(TOKEN, 1)?;
+        s.serialize_field(TOKEN, &self.n)?;
         s.end()
     }
 }
@@ -426,7 +421,7 @@ impl<'de> de::Deserialize<'de> for NumberKey {
             where
                 E: de::Error,
             {
-                if s == SERDE_STRUCT_FIELD_NAME {
+                if s == TOKEN {
                     Ok(())
                 } else {
                     Err(de::Error::custom("expected field with custom name"))
@@ -638,7 +633,7 @@ impl<'de> Deserializer<'de> for NumberFieldDeserializer {
     where
         V: de::Visitor<'de>,
     {
-        visitor.visit_borrowed_str(SERDE_STRUCT_FIELD_NAME)
+        visitor.visit_borrowed_str(TOKEN)
     }
 
     forward_to_deserialize_any! {