revise MsgBoxCreationError

Cargo.toml

@@ -17,6 +17,9 @@ repository = "https://github.com/bekker/msgbox-rs"
 keywords = ["msgbox", "gui", "gtk"]
 license = "MIT"
 
+[dependencies]
+thiserror = "1.0"
+
 [target.'cfg(target_os = "windows")'.dependencies]
 winapi = { version = "^0.3.8", features = ["winuser"] }
 

examples/hello_world.rs

@@ -1,6 +1,7 @@
 extern crate msgbox;
 
 use msgbox::IconType;
+use std::error::Error;
 
 fn main() {
     open_window("Hello Title", "Hello World!", IconType::Info);
@@ -10,7 +11,12 @@ fn main() {
 fn open_window(title: &str, content: &str, icon_type: IconType) {
     match msgbox::create(title, content, icon_type) {
         Ok(()) => (),
-        Err(err) => eprintln!("Failed to open window (type: {}, title: \"{}\", content: \"{}\")",
-            err.icon_type, err.title, err.content),
+        Err(err) => {
+            eprintln!("{} (type: {}, title: \"{}\", content: \"{}\")",
+                err, icon_type, title, content);
+            if err.source().is_some() {
+                eprintln!("cause: {}", err.source().unwrap())
+            }
+        }
     }
 }

src/common.rs

@@ -1,19 +1,20 @@
-#[derive(Debug)]
+use std::{fmt, error};
+
+#[derive(Debug, Copy, Clone)]
 pub enum IconType {
     Error,
     Info,
     None,
 }
 
-impl std::fmt::Display for IconType {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        std::fmt::Debug::fmt(self, f)
+impl fmt::Display for IconType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(self, f)
     }
 }
 
-#[derive(Debug)]
-pub struct MsgBoxCreationError<'a> {
-    pub title: &'a str,
-    pub content: &'a str,
-    pub icon_type: IconType,
+#[derive(thiserror::Error, Debug)]
+pub enum MsgBoxError {
+    #[error("failed to create a message box")]
+    Create{#[source] source: Option<Box<dyn error::Error>>},
 }

src/lib.rs

@@ -1,5 +1,7 @@
+extern crate thiserror;
+
 mod common;
-pub use common::{IconType, MsgBoxCreationError};
+pub use common::{IconType, MsgBoxError};
 
 /**
  * GTK+3

src/linux.rs

@@ -2,15 +2,17 @@ use ::gtk;
 use ::gtk::prelude::*;
 use ::gtk::{ButtonsType, DialogFlags, MessageType, MessageDialog};
 
-use common::{IconType, MsgBoxCreationError};
+use common::{IconType, MsgBoxError};
 
-pub fn create<'a>(title:&'a str, content:&'a str, icon_type:IconType) -> std::result::Result<(), MsgBoxCreationError<'a>> {
+#[derive(thiserror::Error, Debug)]
+pub enum GtkError {
+    #[error("failed to initialize GTK")]
+    Init,
+}
+
+pub fn create(title:&str, content:&str, icon_type:IconType) -> std::result::Result<(), MsgBoxError> {
     if gtk::init().is_err() {
-        return Err(MsgBoxCreationError {
-            title,
-            content,
-            icon_type
-        });
+        return Err(MsgBoxError::Create{source: Some(Box::new(GtkError::Init))})
     }
 
     let message_type = match icon_type {

src/macos.rs

@@ -4,7 +4,7 @@
 use cocoa::base::{id, nil};
 use cocoa::foundation::NSString;
 
-use common::{IconType, MsgBoxCreationError};
+use common::{IconType, MsgBoxError};
 
 /**
  * cocoa-rs doesn't implement NSAlert yet (0.14.0)
@@ -86,7 +86,7 @@ impl NSAlert for id {
     }
 }
 
-pub fn create<'a>(title: &'a str, content: &'a str, icon_type: IconType) -> std::result::Result<(), MsgBoxCreationError<'a>> {
+pub fn create(title: &str, content: &str, icon_type: IconType) -> std::result::Result<(), MsgBoxError> {
     let alert_style = match icon_type {
         IconType::Error => NSAlertStyle::critical,
         IconType::Info => NSAlertStyle::informational,

src/windows.rs

@@ -4,9 +4,9 @@ use winapi::um::winuser::{
     MessageBoxW, MB_ICONERROR, MB_ICONINFORMATION, MB_OK, MB_SYSTEMMODAL,
 };
 
-use common::{IconType, MsgBoxCreationError};
+use common::{IconType, MsgBoxError};
 
-pub fn create<'a>(title: &'a str, content: &'a str, icon_type: IconType) -> std::result::Result<(), MsgBoxCreationError<'a>> {
+pub fn create(title: &str, content: &str, icon_type: IconType) -> std::result::Result<(), MsgBoxError> {
 
     let lp_text: Vec<u16> = content.encode_utf16().chain(once(0)).collect();
     let lp_caption: Vec<u16> = title.encode_utf16().chain(once(0)).collect();
@@ -28,11 +28,7 @@ pub fn create<'a>(title: &'a str, content: &'a str, icon_type: IconType) -> std:
             lp_caption.as_ptr(),
             window_type,
         ) {
-            0 => Err(MsgBoxCreationError {
-                title,
-                content,
-                icon_type
-            }),
+            0 => Err(MsgBoxError::Create{source: None}),
             _ => Ok(())
         }
     }