1 files changed, 77 insertions, 0 deletions
diff --git a/third_party/rust/serde_urlencoded/src/ser/key.rs b/third_party/rust/serde_urlencoded/src/ser/key.rs
new file mode 100644
index 0000000000..8128a64ebb
--- /dev/null
+++ b/third_party/rust/serde_urlencoded/src/ser/key.rs
@@ -0,0 +1,77 @@
+use crate::ser::part::Sink;
+use crate::ser::Error;
+use serde::Serialize;
+use std::borrow::Cow;
+use std::ops::Deref;
+
+pub enum Key<'key> {
+    Static(&'static str),
+    Dynamic(Cow<'key, str>),
+}
+
+impl<'key> Deref for Key<'key> {
+    type Target = str;
+
+    fn deref(&self) -> &str {
+        match *self {
+            Key::Static(key) => key,
+            Key::Dynamic(ref key) => key,
+        }
+    }
+}
+
+impl<'key> From<Key<'key>> for Cow<'static, str> {
+    fn from(key: Key<'key>) -> Self {
+        match key {
+            Key::Static(key) => key.into(),
+            Key::Dynamic(key) => key.into_owned().into(),
+        }
+    }
+}
+
+pub struct KeySink<End> {
+    end: End,
+}
+
+impl<End, Ok> KeySink<End>
+where
+    End: for<'key> FnOnce(Key<'key>) -> Result<Ok, Error>,
+{
+    pub fn new(end: End) -> Self {
+        KeySink { end }
+    }
+}
+
+impl<End, Ok> Sink for KeySink<End>
+where
+    End: for<'key> FnOnce(Key<'key>) -> Result<Ok, Error>,
+{
+    type Ok = Ok;
+
+    fn serialize_static_str(self, value: &'static str) -> Result<Ok, Error> {
+        (self.end)(Key::Static(value))
+    }
+
+    fn serialize_str(self, value: &str) -> Result<Ok, Error> {
+        (self.end)(Key::Dynamic(value.into()))
+    }
+
+    fn serialize_string(self, value: String) -> Result<Ok, Error> {
+        (self.end)(Key::Dynamic(value.into()))
+    }
+
+    fn serialize_none(self) -> Result<Ok, Error> {
+        Err(self.unsupported())
+    }
+
+    fn serialize_some<T: ?Sized + Serialize>(
+        self,
+        _value: &T,
+    ) -> Result<Ok, Error> {
+        Err(self.unsupported())
+    }
+
+    fn unsupported(self) -> Error {
+        Error::Custom("unsupported key".into())
+    }
+}