Make `TTS` clonable.

Also, add other possibly useful derives.

Cargo.toml

@@ -16,6 +16,7 @@ crate-type = ["lib", "cdylib", "staticlib"]
 use_tolk = ["tolk"]
 
 [dependencies]
+dyn-clonable = "0.9"
 lazy_static = "1"
 log = "0.4"
 thiserror = "1"
@@ -24,7 +25,7 @@ thiserror = "1"
 env_logger = "0.8"
 
 [target.'cfg(windows)'.dependencies]
-tolk = { version = ">= 0.2.1", optional = true }
+tolk = { version = "0.3", optional = true }
 winrt = "0.7"
 tts_winrt_bindings = { version = "0.1", path="winrt_bindings" }
 

src/backends/appkit.rs

@@ -9,6 +9,7 @@ use objc::*;
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId};
 
+#[derive(Clone)]
 pub(crate) struct AppKit(*mut Object, *mut Object);
 
 impl AppKit {

src/backends/av_foundation.rs

@@ -11,6 +11,7 @@ use objc::{class, declare::ClassDecl, msg_send, sel, sel_impl};
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
+#[derive(Clone)]
 pub(crate) struct AvFoundation {
     id: BackendId,
     delegate: *mut Object,

src/backends/speech_dispatcher.rs

@@ -8,6 +8,7 @@ use speech_dispatcher::*;
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
+#[derive(Clone)]
 pub(crate) struct SpeechDispatcher(Connection);
 
 lazy_static! {

src/backends/tolk.rs

@@ -4,6 +4,7 @@ use tolk::Tolk as TolkPtr;
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId};
 
+#[derive(Clone)]
 pub(crate) struct Tolk(TolkPtr);
 
 impl Tolk {

src/backends/web.rs

@@ -12,6 +12,7 @@ use web_sys::{
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
+#[derive(Clone)]
 pub struct Web {
     id: BackendId,
     rate: f32,

src/backends/winrt.rs

@@ -21,6 +21,7 @@ impl From<winrt::Error> for Error {
     }
 }
 
+#[derive(Clone)]
 pub struct WinRT {
     id: BackendId,
     synth: SpeechSynthesizer,

src/lib.rs

@@ -19,6 +19,7 @@ use std::sync::Mutex;
 
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 use cocoa_foundation::base::id;
+use dyn_clonable::*;
 use lazy_static::lazy_static;
 #[cfg(target_os = "macos")]
 use libc::c_char;
@@ -28,6 +29,7 @@ use thiserror::Error;
 
 mod backends;
 
+#[derive(Clone, Copy, Debug)]
 pub enum Backends {
     #[cfg(target_os = "linux")]
     SpeechDispatcher,
@@ -107,7 +109,8 @@ pub enum Error {
     OutOfRange,
 }
 
-pub trait Backend {
+#[clonable]
+trait Backend: Clone {
     fn id(&self) -> Option<BackendId>;
     fn supported_features(&self) -> Features;
     fn speak(&mut self, text: &str, interrupt: bool) -> Result<Option<UtteranceId>, Error>;
@@ -148,6 +151,7 @@ lazy_static! {
     };
 }
 
+#[derive(Clone)]
 pub struct TTS(Box<dyn Backend>);
 
 unsafe impl Send for TTS {}