add BufferToSmall error case to FFIResult kind

Author: joemphilips

bindings/src/error.rs

@@ -36,6 +36,9 @@ pub enum Kind {
     Ok,
     EmptyPointerProvided,
     InvalidSeedLength,
+    /// Return this when buffer for allocating error message is too small.
+    /// When this is the last error, the caller should try to increase the buffer size and call the function again.
+    BufferTooSmall,
     InternalError,
 }
 
@@ -133,6 +136,14 @@ impl FFIResult {
         self.kind == Kind::EmptyPointerProvided
     }
 
+    pub(super) fn buffer_too_small() -> Self {
+        FFIResult { kind: Kind::BufferTooSmall, id: next_err_id() }
+    }
+
+    pub fn is_buffer_too_small(&self) -> bool {
+        self.kind == Kind::BufferTooSmall
+    }
+
     pub(super) fn invalid_seed_length() -> Self {
         FFIResult { kind: Kind::InvalidSeedLength, id: next_err_id() }
     }
@@ -157,6 +168,7 @@ impl FFIResult {
             Kind::EmptyPointerProvided => Some("a required pointer argument was null"),
             Kind::InvalidSeedLength => Some("provided seed buffer has invalid length"),
             Kind::InternalError => Some("An internal error occured"),
+            Kind::BufferTooSmall => Some("buffer was too small"),
         }
     }