micro_http: check arithmetic operations

Signed-off-by: Ioana Chirca <chioana@amazon.com>
Signed-off-by: YUAN LYU <lyuyuan92@gmail.com>

src/common/mod.rs

@@ -28,6 +28,10 @@ pub enum RequestError {
     InvalidHeader,
     /// The Request is invalid and cannot be served.
     InvalidRequest,
+    /// Overflow occurred when parsing a request.
+    Overflow,
+    /// Underflow occurred when parsing a request.
+    Underflow,
 }
 
 impl Display for RequestError {
@@ -39,6 +43,8 @@ impl Display for RequestError {
             Self::UnsupportedHeader => write!(f, "Unsupported header."),
             Self::InvalidHeader => write!(f, "Invalid header."),
             Self::InvalidRequest => write!(f, "Invalid request."),
+            Self::Overflow => write!(f, "Overflow occurred when parsing a request."),
+            Self::Underflow => write!(f, "Underflow occurred when parsing a request."),
         }
     }
 }
@@ -91,6 +97,10 @@ pub enum ServerError {
     ConnectionError(ConnectionError),
     /// Server maximum capacity has been reached.
     ServerFull,
+    /// Overflow occured while processing messages.
+    Overflow,
+    /// Underflow occured while processing mesagges.
+    Underflow,
 }
 
 impl Display for ServerError {
@@ -99,6 +109,8 @@ impl Display for ServerError {
             Self::IOError(inner) => write!(f, "IO error: {}", inner),
             Self::ConnectionError(inner) => write!(f, "Connection error: {}", inner),
             Self::ServerFull => write!(f, "Server is full."),
+            Self::Overflow => write!(f, "Overflow occured while processing messages."),
+            Self::Underflow => write!(f, "Underflow occured while processing messages."),
         }
     }
 }
@@ -250,9 +262,11 @@ mod tests {
         fn eq(&self, other: &Self) -> bool {
             use self::ConnectionError::*;
             match (self, other) {
-                (ParseError(_), ParseError(_)) => true,
+                (ParseError(ref e), ParseError(ref other_e)) => e.eq(other_e),
                 (ConnectionClosed, ConnectionClosed) => true,
-                (StreamError(_), StreamError(_)) => true,
+                (StreamError(ref e), StreamError(ref other_e)) => {
+                    format!("{}", e).eq(&format!("{}", other_e))
+                }
                 (InvalidWrite, InvalidWrite) => true,
                 _ => false,
             }
@@ -309,29 +323,37 @@ mod tests {
     #[test]
     fn test_display_request_error() {
         assert_eq!(
-            format!("{}", RequestError::InvalidHttpMethod("test")),
-            "Invalid HTTP Method: test"
+            format!("{}", RequestError::InvalidHeader),
+            "Invalid header."
         );
         assert_eq!(
-            format!("{}", RequestError::InvalidUri("test")),
-            "Invalid URI: test"
+            format!("{}", RequestError::InvalidHttpMethod("test")),
+            "Invalid HTTP Method: test"
         );
         assert_eq!(
             format!("{}", RequestError::InvalidHttpVersion("test")),
             "Invalid HTTP Version: test"
         );
         assert_eq!(
-            format!("{}", RequestError::InvalidHeader),
-            "Invalid header."
+            format!("{}", RequestError::InvalidRequest),
+            "Invalid request."
+        );
+        assert_eq!(
+            format!("{}", RequestError::InvalidUri("test")),
+            "Invalid URI: test"
+        );
+        assert_eq!(
+            format!("{}", RequestError::Overflow),
+            "Overflow occurred when parsing a request."
+        );
+        assert_eq!(
+            format!("{}", RequestError::Underflow),
+            "Underflow occurred when parsing a request."
         );
         assert_eq!(
             format!("{}", RequestError::UnsupportedHeader),
             "Unsupported header."
         );
-        assert_eq!(
-            format!("{}", RequestError::InvalidRequest),
-            "Invalid request."
-        );
     }
 
     #[test]
@@ -377,6 +399,14 @@ mod tests {
             ),
             "IO error: Resource temporarily unavailable (os error 11)"
         );
+        assert_eq!(
+            format!("{}", ServerError::Overflow),
+            "Overflow occured while processing messages."
+        );
+        assert_eq!(
+            format!("{}", ServerError::Underflow),
+            "Underflow occured while processing messages."
+        );
     }
 
     #[test]