Start on copy-paste

gpui/src/app.rs

@@ -1215,6 +1215,10 @@ impl MutableAppContext {
     pub fn copy(&self, text: &str) {
         self.platform.copy(text);
     }
+
+    pub fn paste(&self) -> Option<String> {
+        self.platform.paste()
+    }
 }
 
 impl ReadModel for MutableAppContext {

gpui/src/platform/mac/platform.rs

@@ -26,6 +26,7 @@ use std::{
     path::PathBuf,
     ptr,
     rc::Rc,
+    slice,
     sync::Arc,
 };
 
@@ -299,6 +300,19 @@ impl platform::Platform for MacPlatform {
         }
     }
 
+    fn paste(&self) -> Option<String> {
+        unsafe {
+            let pasteboard = NSPasteboard::generalPasteboard(nil);
+            let data = pasteboard.dataForType(NSPasteboardTypeString);
+            if data == nil {
+                None
+            } else {
+                let bytes = slice::from_raw_parts(data.bytes() as *mut u8, data.length() as usize);
+                Some(String::from_utf8_unchecked(bytes.to_vec()))
+            }
+        }
+    }
+
     fn set_menus(&self, menus: Vec<Menu>) {
         unsafe {
             let app: id = msg_send![APP_CLASS, sharedApplication];

gpui/src/platform/mod.rs

@@ -43,6 +43,7 @@ pub trait Platform {
     fn prompt_for_paths(&self, options: PathPromptOptions) -> Option<Vec<PathBuf>>;
     fn quit(&self);
     fn copy(&self, text: &str);
+    fn paste(&self) -> Option<String>;
     fn set_menus(&self, menus: Vec<Menu>);
 }
 

gpui/src/platform/test.rs

@@ -73,6 +73,10 @@ impl super::Platform for Platform {
     }
 
     fn copy(&self, _: &str) {}
+
+    fn paste(&self) -> Option<String> {
+        None
+    }
 }
 
 impl Window {