feat: add libnotify error

src/api/errors.rs

@@ -0,0 +1,37 @@
+/// Enum mapping every possible error that can happen in this lib, with a nice enum.
+#[derive(Debug)]
+pub enum LibnotifyError {
+    /// [libnotify init](https://gnome.pages.gitlab.gnome.org/libnotify/func.init.html) failed
+    InitFail,
+    /// `&str` contains a null terminator. Read more at [std documentation](https://doc.rust-lang.org/std/ffi/struct.NulError.html)
+    NulError(std::ffi::NulError),
+}
+
+impl std::fmt::Display for LibnotifyError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::InitFail => {
+                write!(f, "Libnotify failed to init")
+            }
+
+            Self::NulError(_) => {
+                write!(f, "Argument contains a null terminator")
+            }
+        }
+    }
+}
+
+impl std::error::Error for LibnotifyError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            Self::InitFail => None,
+            Self::NulError(e) => Some(e),
+        }
+    }
+}
+
+impl From<std::ffi::NulError> for LibnotifyError {
+    fn from(value: std::ffi::NulError) -> Self {
+        Self::NulError(value)
+    }
+}