create and use LogError enum

Author: YruamaLairba

log/src/lib.rs

@@ -56,6 +56,19 @@ unsafe impl EntryType for URID<WarningClass> {
     }
 }
 
+/// Errors potentially generated by [`Log`](struct.Log.html) methods
+#[derive(PartialEq, Eq, Clone, Copy, Debug)]
+pub enum LogError {
+    /// An error occured when sending message to the host
+    PrintError,
+    /// The provided string don't have a `'\0'` to indicate it's end
+    NoNullTerminator,
+    /// No callback was provided by the host
+    ///
+    /// This can only happen with a faulty host
+    NoCallback,
+}
+
 /// The Log feature
 #[repr(transparent)]
 pub struct Log<'a> {
@@ -77,11 +90,11 @@ unsafe impl<'a> Feature for Log<'a> {
 }
 
 impl<'a> Log<'a> {
-    pub fn print(&self, entry_type: impl EntryType, message: &str) -> Result<(), ()> {
+    pub fn print(&self, entry_type: impl EntryType, message: &str) -> Result<(), LogError> {
         let printf = if let Some(printf) = self.internal.printf {
             printf
         } else {
-            return Err(());
+            return Err(LogError::NoCallback);
         };
         //checking for null terminator
         let mut have_null = false;
@@ -92,7 +105,7 @@ impl<'a> Log<'a> {
             }
         }
         if !have_null {
-            return Err(());
+            return Err(LogError::NoNullTerminator);
         }
 
         let res = unsafe {
@@ -106,7 +119,7 @@ impl<'a> Log<'a> {
         if res > 0 {
             Ok(())
         } else {
-            Err(())
+            Err(LogError::PrintError)
         }
     }
 }