Rework commands and make them statically typed. (#993)

CHANGELOG.md

@@ -72,6 +72,7 @@ This means that druid no longer requires cairo on macOS and uses Core Graphics i
 - Replaced `NEW_WINDOW`, `SET_MENU` and `SHOW_CONTEXT_MENU` commands with methods on `EventCtx` and `DelegateCtx`. ([#931] by [@finnerale])
 - Replaced `Command::one_shot` and `::take_object` with a `SingleUse` payload wrapper type. ([#959] by [@finnerale])
 - Renamed `WidgetPod` methods: `paint` to `paint_raw`, `paint_with_offset` to `paint`, `paint_with_offset_always` to `paint_always`. ([#980] by [@totsteps])
+- `Command` and `Selector` have been reworked and are now statically typed, similarly to `Env` and `Key`. ([#993] by [@finnerale])
 
 ### Deprecated
 
@@ -242,6 +243,7 @@ This means that druid no longer requires cairo on macOS and uses Core Graphics i
 [#984]: https://github.com/xi-editor/druid/pull/984
 [#990]: https://github.com/xi-editor/druid/pull/990
 [#991]: https://github.com/xi-editor/druid/pull/991
+[#993]: https://github.com/xi-editor/druid/pull/993
 
 ## [0.5.0] - 2020-04-01
 

druid/examples/blocking_function.rs

@@ -23,9 +23,9 @@ use druid::{
 
 use druid::widget::{Button, Either, Flex, Label};
 
-const START_SLOW_FUNCTION: Selector = Selector::new("start_slow_function");
+const START_SLOW_FUNCTION: Selector<u32> = Selector::new("start_slow_function");
 
-const FINISH_SLOW_FUNCTION: Selector = Selector::new("finish_slow_function");
+const FINISH_SLOW_FUNCTION: Selector<u32> = Selector::new("finish_slow_function");
 
 struct Delegate {
     eventsink: ExtEventSink,
@@ -61,20 +61,15 @@ impl AppDelegate<AppState> for Delegate {
         data: &mut AppState,
         _env: &Env,
     ) -> bool {
-        match cmd.selector {
-            START_SLOW_FUNCTION => {
-                data.processing = true;
-                wrapped_slow_function(self.eventsink.clone(), data.value);
-                true
-            }
-            FINISH_SLOW_FUNCTION => {
-                data.processing = false;
-                let number = cmd.get_object::<u32>().expect("api violation");
-                data.value = *number;
-                true
-            }
-            _ => true,
+        if cmd.is(START_SLOW_FUNCTION) {
+            data.processing = true;
+            wrapped_slow_function(self.eventsink.clone(), data.value);
         }
+        if let Some(number) = cmd.get(FINISH_SLOW_FUNCTION) {
+            data.processing = false;
+            data.value = *number;
+        }
+        true
     }
 }
 

druid/examples/ext_event.rs

@@ -22,7 +22,7 @@ use druid::kurbo::RoundedRect;
 use druid::widget::prelude::*;
 use druid::{AppLauncher, Color, Data, LocalizedString, Rect, Selector, WidgetExt, WindowDesc};
 
-const SET_COLOR: Selector = Selector::new("event-example.set-color");
+const SET_COLOR: Selector<Color> = Selector::new("event-example.set-color");
 
 /// A widget that displays a color.
 struct ColorWell;
@@ -53,8 +53,8 @@ impl ColorWell {
 impl Widget<MyColor> for ColorWell {
     fn event(&mut self, ctx: &mut EventCtx, event: &Event, data: &mut MyColor, _env: &Env) {
         match event {
-            Event::Command(cmd) if cmd.selector == SET_COLOR => {
-                data.0 = cmd.get_object::<Color>().unwrap().clone();
+            Event::Command(cmd) if cmd.is(SET_COLOR) => {
+                data.0 = cmd.get_unchecked(SET_COLOR).clone();
                 ctx.request_paint();
             }
             _ => (),

druid/examples/identity.rs

@@ -40,7 +40,7 @@ use druid::{
 
 const CYCLE_DURATION: Duration = Duration::from_millis(100);
 
-const FREEZE_COLOR: Selector = Selector::new("identity-example.freeze-color");
+const FREEZE_COLOR: Selector<Color> = Selector::new("identity-example.freeze-color");
 const UNFREEZE_COLOR: Selector = Selector::new("identity-example.unfreeze-color");
 
 /// Honestly: it's just a color in fancy clothing.
@@ -109,20 +109,13 @@ impl Widget<OurData> for ColorWell {
                 self.token = ctx.request_timer(CYCLE_DURATION);
                 ctx.request_paint();
             }
-
             Event::WindowConnected if self.randomize => {
                 self.token = ctx.request_timer(CYCLE_DURATION);
             }
-
-            Event::Command(cmd) if cmd.selector == FREEZE_COLOR => {
-                self.frozen = cmd
-                    .get_object::<Color>()
-                    .ok()
-                    .cloned()
-                    .expect("payload is always a Color")
-                    .into();
+            Event::Command(cmd) if cmd.is(FREEZE_COLOR) => {
+                self.frozen = cmd.get(FREEZE_COLOR).cloned();
             }
-            Event::Command(cmd) if cmd.selector == UNFREEZE_COLOR => self.frozen = None,
+            Event::Command(cmd) if cmd.is(UNFREEZE_COLOR) => self.frozen = None,
             _ => (),
         }
     }

druid/examples/multiwin.rs

@@ -25,7 +25,7 @@ use druid::{
 };
 use log::info;
 
-const MENU_COUNT_ACTION: Selector = Selector::new("menu-count-action");
+const MENU_COUNT_ACTION: Selector<usize> = Selector::new("menu-count-action");
 const MENU_INCREMENT_ACTION: Selector = Selector::new("menu-increment-action");
 const MENU_DECREMENT_ACTION: Selector = Selector::new("menu-decrement-action");
 const MENU_SWITCH_GLOW_ACTION: Selector = Selector::new("menu-switch-glow");
@@ -155,16 +155,16 @@ impl AppDelegate<State> for Delegate {
         data: &mut State,
         _env: &Env,
     ) -> bool {
-        match cmd.selector {
-            sys_cmds::NEW_FILE => {
+        match cmd {
+            _ if cmd.is(sys_cmds::NEW_FILE) => {
                 let new_win = WindowDesc::new(ui_builder)
                     .menu(make_menu(data))
                     .window_size((data.selected as f64 * 100.0 + 300.0, 500.0));
                 ctx.new_window(new_win);
                 false
             }
-            MENU_COUNT_ACTION => {
-                data.selected = *cmd.get_object().unwrap();
+            _ if cmd.is(MENU_COUNT_ACTION) => {
+                data.selected = *cmd.get_unchecked(MENU_COUNT_ACTION);
                 let menu = make_menu::<State>(data);
                 for id in &self.windows {
                     ctx.set_menu(menu.clone(), *id);
@@ -173,23 +173,23 @@ impl AppDelegate<State> for Delegate {
             }
             // wouldn't it be nice if a menu (like a button) could just mutate state
             // directly if desired?
-            MENU_INCREMENT_ACTION => {
+            _ if cmd.is(MENU_INCREMENT_ACTION) => {
                 data.menu_count += 1;
                 let menu = make_menu::<State>(data);
                 for id in &self.windows {
                     ctx.set_menu(menu.clone(), *id);
                 }
                 false
             }
-            MENU_DECREMENT_ACTION => {
+            _ if cmd.is(MENU_DECREMENT_ACTION) => {
                 data.menu_count = data.menu_count.saturating_sub(1);
                 let menu = make_menu::<State>(data);
                 for id in &self.windows {
                     ctx.set_menu(menu.clone(), *id);
                 }
                 false
             }
-            MENU_SWITCH_GLOW_ACTION => {
+            _ if cmd.is(MENU_SWITCH_GLOW_ACTION) => {
                 data.glow_hot = !data.glow_hot;
                 false
             }

druid/examples/open_save.rs

@@ -14,7 +14,7 @@
 
 use druid::widget::{Align, Button, Flex, TextBox};
 use druid::{
-    AppDelegate, AppLauncher, Command, DelegateCtx, Env, FileDialogOptions, FileInfo, FileSpec,
+    commands, AppDelegate, AppLauncher, Command, DelegateCtx, Env, FileDialogOptions, FileSpec,
     LocalizedString, Target, Widget, WindowDesc,
 };
 
@@ -77,30 +77,24 @@ impl AppDelegate<String> for Delegate {
         data: &mut String,
         _env: &Env,
     ) -> bool {
-        match cmd.selector {
-            druid::commands::SAVE_FILE => {
-                if let Ok(file_info) = cmd.get_object::<FileInfo>() {
-                    if let Err(e) = std::fs::write(file_info.path(), &data[..]) {
-                        println!("Error writing file: {}", e);
-                    }
-                }
-                true
+        if let Some(Some(file_info)) = cmd.get(commands::SAVE_FILE) {
+            if let Err(e) = std::fs::write(file_info.path(), &data[..]) {
+                println!("Error writing file: {}", e);
             }
-            druid::commands::OPEN_FILE => {
-                if let Ok(file_info) = cmd.get_object::<FileInfo>() {
-                    match std::fs::read_to_string(file_info.path()) {
-                        Ok(s) => {
-                            let first_line = s.lines().next().unwrap_or("");
-                            *data = first_line.to_owned();
-                        }
-                        Err(e) => {
-                            println!("Error opening file: {}", e);
-                        }
-                    }
+            return true;
+        }
+        if let Some(file_info) = cmd.get(commands::OPEN_FILE) {
+            match std::fs::read_to_string(file_info.path()) {
+                Ok(s) => {
+                    let first_line = s.lines().next().unwrap_or("");
+                    *data = first_line.to_owned();
+                }
+                Err(e) => {
+                    println!("Error opening file: {}", e);
                 }
-                true
             }
-            _ => false,
+            return true;
         }
+        false
     }
 }

druid/src/app_delegate.rs

@@ -57,7 +57,7 @@ impl<'a> DelegateCtx<'a> {
     pub fn new_window<T: Any>(&mut self, desc: WindowDesc<T>) {
         if self.app_data_type == TypeId::of::<T>() {
             self.submit_command(
-                Command::new(commands::NEW_WINDOW, SingleUse::new(desc)),
+                Command::new(commands::NEW_WINDOW, SingleUse::new(Box::new(desc))),
                 Target::Global,
             );
         } else {
@@ -77,7 +77,7 @@ impl<'a> DelegateCtx<'a> {
     pub fn set_menu<T: Any>(&mut self, menu: MenuDesc<T>, window: WindowId) {
         if self.app_data_type == TypeId::of::<T>() {
             self.submit_command(
-                Command::new(commands::SET_MENU, menu),
+                Command::new(commands::SET_MENU, Box::new(menu)),
                 Target::Window(window),
             );
         } else {