turn KeyEncoder into a marker trait

libs/proxy/json/src/lib.rs

@@ -81,7 +81,7 @@ mod macros;
 mod str;
 mod value;
 
-pub use value::{Null, ValueEncoder};
+pub use value::{KeyEncoder, Null, ValueEncoder};
 
 #[must_use]
 /// Serialize a single json value.
@@ -164,7 +164,9 @@ impl<'buf> ObjectSer<'buf> {
     /// Start a new object entry with the given string key, returning a [`ValueSer`] for the associated value.
     #[inline]
     pub fn key(&mut self, key: impl KeyEncoder) -> ValueSer<'_> {
-        key.write_key(self)
+        // we create a psuedo value to write the key into.
+        let start = self.start;
+        self.entry_inner(|buf| key.encode(ValueSer { buf, start }))
     }
 
     /// Write an entry (key-value pair) to the object.
@@ -211,10 +213,6 @@ impl<'buf> ObjectSer<'buf> {
     }
 }
 
-pub trait KeyEncoder {
-    fn write_key<'a>(self, obj: &'a mut ObjectSer) -> ValueSer<'a>;
-}
-
 #[must_use]
 /// Serialize a json object.
 pub struct ListSer<'buf> {

libs/proxy/json/src/value.rs

@@ -2,10 +2,13 @@ use core::fmt;
 use std::collections::{BTreeMap, HashMap};
 
 use crate::str::{format_escaped_fmt, format_escaped_str};
-use crate::{KeyEncoder, ObjectSer, ValueSer, value_as_list, value_as_object};
+use crate::{ValueSer, value_as_list, value_as_object};
+
+/// Marker trait for values that are valid keys
+pub trait KeyEncoder: ValueEncoder {}
 
 /// Write a value to the underlying json representation.
-pub trait ValueEncoder {
+pub trait ValueEncoder: Sized {
     fn encode(self, v: ValueSer<'_>);
 }
 
@@ -24,6 +27,7 @@ impl<T: Copy + ValueEncoder> ValueEncoder for &T {
     }
 }
 
+impl KeyEncoder for &str {}
 impl ValueEncoder for &str {
     #[inline]
     fn encode(self, v: ValueSer<'_>) {
@@ -32,6 +36,7 @@ impl ValueEncoder for &str {
     }
 }
 
+impl KeyEncoder for String {}
 impl ValueEncoder for String {
     #[inline]
     fn encode(self, v: ValueSer<'_>) {
@@ -39,6 +44,7 @@ impl ValueEncoder for String {
     }
 }
 
+impl KeyEncoder for fmt::Arguments<'_> {}
 impl ValueEncoder for fmt::Arguments<'_> {
     #[inline]
     fn encode(self, v: ValueSer<'_>) {
@@ -101,32 +107,6 @@ impl<T: ValueEncoder> ValueEncoder for Option<T> {
     }
 }
 
-impl KeyEncoder for &str {
-    #[inline]
-    fn write_key<'a>(self, obj: &'a mut ObjectSer) -> ValueSer<'a> {
-        let obj = &mut *obj;
-        obj.entry_inner(|b| format_escaped_str(b, self))
-    }
-}
-
-impl KeyEncoder for String {
-    #[inline]
-    fn write_key<'a>(self, obj: &'a mut ObjectSer) -> ValueSer<'a> {
-        self.as_str().write_key(obj)
-    }
-}
-
-impl KeyEncoder for fmt::Arguments<'_> {
-    #[inline]
-    fn write_key<'a>(self, obj: &'a mut ObjectSer) -> ValueSer<'a> {
-        if let Some(key) = self.as_str() {
-            obj.entry_inner(|b| format_escaped_str(b, key))
-        } else {
-            obj.entry_inner(|b| format_escaped_fmt(b, self))
-        }
-    }
-}
-
 /// Represents the JSON null value.
 pub struct Null;