split up http body module

actix-http/src/body/size.rs

@@ -0,0 +1,40 @@
+/// Body size hint.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum BodySize {
+    /// Absence of body can be assumed from method or status code.
+    ///
+    /// Will skip writing Content-Length header.
+    None,
+
+    /// Zero size body.
+    ///
+    /// Will write `Content-Length: 0` header.
+    Empty,
+
+    /// Known size body.
+    ///
+    /// Will write `Content-Length: N` header. `Sized(0)` is treated the same as `Empty`.
+    Sized(u64),
+
+    /// Unknown size body.
+    ///
+    /// Will not write Content-Length header. Can be used with chunked Transfer-Encoding.
+    Stream,
+}
+
+impl BodySize {
+    /// Returns true if size hint indicates no or empty body.
+    ///
+    /// ```
+    /// # use actix_http::body::BodySize;
+    /// assert!(BodySize::None.is_eof());
+    /// assert!(BodySize::Empty.is_eof());
+    /// assert!(BodySize::Sized(0).is_eof());
+    ///
+    /// assert!(!BodySize::Sized(64).is_eof());
+    /// assert!(!BodySize::Stream.is_eof());
+    /// ```
+    pub fn is_eof(&self) -> bool {
+        matches!(self, BodySize::None | BodySize::Empty | BodySize::Sized(0))
+    }
+}