perf: avoid JXA startup for macOS clipboard writes

2026-10-13 11:05:37 +02:00
parent 8c5d218c11
commit b94739183d
4 changed files with 194 additions and 39 deletions
@@ -20,7 +20,8 @@
    - Space s flips orientation; configurable startup default and shared pane geometry/directional focus.
 - [x] add `C` and `D` for deleting line from current cursor position (and entering insert mode: `C`); add `Y` for copying line from current cursor position; add `r` for replacing character at cursor position; add `s` for deleting character at current cursor position and entering insert mode; add `d<count>w` for deleting whole words; add `d<count>b` for deleting backwards (same as `d<count>w` but backwards).
 - [x] diff view: make foreground of etched areas (where no lines exist) the same dimmed color as the normal gutter text
- [ ] copying is pretty slow; optimize performance to reduce latency. 
+- [x] copying is pretty slow; optimize performance to reduce latency.
+- [ ] enable margins in bar elements (i.e. for top and bottom bars) and give the lsp symbol (next to language) a default margin of 1 column on either side.
 - [ ] pull a pr description and display it in a buffer:
 	- open a selector that allows you to pick a pr from remote
 	- selector should be searchable
@@ -91,7 +91,7 @@ Diff highlighting lazily owns two instances of the same syntax cache, keyed by t

 ## Clipboard providers

-macOS uses fixed JXA/AppKit `NSPasteboardTypeString` access through `osascript`, preserving literal RTF/EPS text rather than treating it as rich clipboard data. Linux supports Wayland with `wl-paste`/`wl-copy`, or X11 with `xclip`, on PATH with the corresponding display environment. Other platforms report unsupported access. Commands have a two-second deadline and bounded output; failures terminate/reap their process group.
+macOS publishes `public.utf8-plain-text` through the native Pasteboard Manager, checking allocation and OS-status failures before reporting success. Publication is synchronous and avoids per-copy interpreter/process startup; native calls do not have a subprocess deadline. Reads retain fixed JXA/AppKit `NSPasteboardTypeString` access through `osascript`. Both paths preserve literal RTF/EPS text rather than treating it as rich clipboard data. Linux supports Wayland with `wl-paste`/`wl-copy`, or X11 with `xclip`, on PATH with the corresponding display environment. Other platforms report unsupported access. Subprocess-backed access has a two-second deadline and bounded output; failures terminate/reap the process group.

 ## Native LSP

@@ -134,7 +134,7 @@ For other applications, characterwise multi-selection exports join fragments wit

 System paste validates UTF-8, unsupported controls, newlines, and a 4 MiB limit before editing; CRLF/CR normalize to LF. System exports also have a 4 MiB limit. Provider failures report an error without deleting/changing buffer text, caret/selection state, history, or repeat intent. No silent internal fallback occurs in System mode; choose Separate if clipboard access is unavailable. A native provider that fails after publishing may already have changed OS clipboard formats; vamp cannot roll that external side effect back.

-System clipboard access supports macOS through `osascript`, Linux Wayland through `wl-paste`/`wl-copy`, and Linux X11 through `xclip`. Linux tools must be on PATH with the corresponding display environment. Other platforms report unsupported access; choose Separate mode when system clipboard access is unavailable.
+macOS copies publish UTF-8 plain text directly through the native pasteboard API, avoiding interpreter/process startup for every copy or cut; paste reads still use `osascript` with JXA/AppKit. Linux Wayland uses `wl-paste`/`wl-copy`, and Linux X11 uses `xclip`. Linux tools must be on PATH with the corresponding display environment. Other platforms report unsupported access; choose Separate mode when system clipboard access is unavailable.

 ## Repeat last edit

@@ -15,20 +15,6 @@ function run() {
 }
 "#;

-#[cfg(target_os = "macos")]
-const MAC_WRITE: &str = r#"
-ObjC.import('AppKit');
-function run() {
-    var data = $.NSFileHandle.fileHandleWithStandardInput.readDataToEndOfFile;
-    var text = $.NSString.alloc.initWithDataEncoding(data, $.NSUTF8StringEncoding);
-    if (text.isNil()) throw Error('Clipboard input is not UTF-8');
-    var pasteboard = $.NSPasteboard.generalPasteboard;
-    pasteboard.clearContents;
-    if (!pasteboard.setStringForType(text, $.NSPasteboardTypeString))
-        throw Error('Cannot write plain-text clipboard');
-}
-"#;
-
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum ClipboardMode {
    System,
@@ -42,7 +28,7 @@ struct ClipboardCommand {

 struct Commands {
    reader: ClipboardCommand,
-    writer: ClipboardCommand,
+    writer: Option<ClipboardCommand>,
 }

 pub struct SystemClipboard {
@@ -72,10 +58,10 @@ impl SystemClipboard {
                    program: reader,
                    args: &[],
                },
-                writer: ClipboardCommand {
+                writer: Some(ClipboardCommand {
                    program: writer,
                    args: &[],
-                },
+                }),
            })),
            timeout: COMMAND_TIMEOUT,
        }
@@ -95,8 +81,13 @@ impl SystemClipboard {
        }
        let timeout = self.timeout;
        let commands = self.commands.get_or_insert_with(select_commands);
-        let command = &commands.as_ref().map_err(Clone::clone)?.writer;
-        run(command, Some(text.as_bytes()), timeout).map(|_| ())
+        match &commands.as_ref().map_err(Clone::clone)?.writer {
+            Some(command) => run(command, Some(text.as_bytes()), timeout).map(|_| ()),
+            #[cfg(target_os = "macos")]
+            None => macos::write(text),
+            #[cfg(not(target_os = "macos"))]
+            None => Err("System clipboard is unsupported on this platform".into()),
+        }
    }
 }

@@ -117,19 +108,13 @@ fn executable(name: &str) -> Option<PathBuf> {
 fn select_commands() -> Result<Commands, String> {
    #[cfg(target_os = "macos")]
    {
-        if let Some(program) = executable("osascript") {
-            return Ok(Commands {
+        Ok(Commands {
            reader: ClipboardCommand {
-                    program: program.clone(),
+                program: executable("osascript").unwrap_or_else(|| "/usr/bin/osascript".into()),
                args: &["-l", "JavaScript", "-e", MAC_READ],
            },
-                writer: ClipboardCommand {
-                    program,
-                    args: &["-l", "JavaScript", "-e", MAC_WRITE],
-                },
-            });
-        }
-        Err("System clipboard requires osascript with JXA/AppKit on PATH".into())
+            writer: None,
+        })
    }
    #[cfg(target_os = "linux")]
    {
@@ -140,10 +125,10 @@ fn select_commands() -> Result<Commands, String> {
                        program: reader,
                        args: &["--no-newline", "--type", "text"],
                    },
-                    writer: ClipboardCommand {
+                    writer: Some(ClipboardCommand {
                        program: writer,
                        args: &["--type", "text/plain;charset=utf-8"],
-                    },
+                    }),
                });
            }
        }
@@ -154,10 +139,10 @@ fn select_commands() -> Result<Commands, String> {
                        program: program.clone(),
                        args: &["-selection", "clipboard", "-target", "UTF8_STRING", "-out"],
                    },
-                    writer: ClipboardCommand {
+                    writer: Some(ClipboardCommand {
                        program,
                        args: &["-selection", "clipboard", "-target", "UTF8_STRING", "-in"],
-                    },
+                    }),
                });
            }
        }
@@ -169,6 +154,173 @@ fn select_commands() -> Result<Commands, String> {
    }
 }

+#[cfg(target_os = "macos")]
+mod macos {
+    use std::ffi::{c_char, c_void};
+    use std::ptr;
+
+    type Object = *const c_void;
+
+    #[link(name = "CoreFoundation", kind = "framework")]
+    unsafe extern "C" {
+        fn CFStringCreateWithCString(
+            allocator: Object,
+            bytes: *const c_char,
+            encoding: u32,
+        ) -> Object;
+        fn CFDataCreate(allocator: Object, bytes: *const u8, length: isize) -> Object;
+        fn CFRelease(object: Object);
+    }
+
+    #[link(name = "CoreServices", kind = "framework")]
+    unsafe extern "C" {
+        static kUTTypeUTF8PlainText: Object;
+    }
+
+    #[link(name = "ApplicationServices", kind = "framework")]
+    unsafe extern "C" {
+        fn PasteboardCreate(name: Object, pasteboard: *mut Object) -> i32;
+        fn PasteboardClear(pasteboard: Object) -> i32;
+        fn PasteboardPutItemFlavor(
+            pasteboard: Object,
+            item: usize,
+            flavor: Object,
+            data: Object,
+            flags: u32,
+        ) -> i32;
+    }
+
+    struct Owned(Object);
+    impl Owned {
+        fn new(object: Object) -> Result<Self, String> {
+            if object.is_null() {
+                Err("Cannot allocate system clipboard data".into())
+            } else {
+                Ok(Self(object))
+            }
+        }
+    }
+    impl Drop for Owned {
+        fn drop(&mut self) {
+            // SAFETY: each handle owns one Core Foundation reference.
+            unsafe { CFRelease(self.0) };
+        }
+    }
+
+    fn check(status: i32) -> Result<(), String> {
+        if status == 0 {
+            Ok(())
+        } else {
+            Err(format!("System clipboard publication failed ({status})"))
+        }
+    }
+
+    fn write_to(name: Object, text: &str) -> Result<(), String> {
+        // SAFETY: framework constants and byte slices live throughout the calls.
+        unsafe {
+            let data = Owned::new(CFDataCreate(
+                ptr::null(),
+                text.as_ptr(),
+                text.len() as isize,
+            ))?;
+            let mut board = ptr::null();
+            check(PasteboardCreate(name, &mut board))?;
+            let board = Owned::new(board)?;
+            // Prepare all allocations before changing clipboard contents.
+            check(PasteboardClear(board.0))?;
+            check(PasteboardPutItemFlavor(
+                board.0,
+                1,
+                kUTTypeUTF8PlainText,
+                data.0,
+                0,
+            ))
+        }
+    }
+
+    pub(super) fn write(text: &str) -> Result<(), String> {
+        // SAFETY: the clipboard name is a process-lifetime, null-terminated literal.
+        let name = unsafe {
+            Owned::new(CFStringCreateWithCString(
+                ptr::null(),
+                c"com.apple.pasteboard.clipboard".as_ptr(),
+                0x0800_0100,
+            ))?
+        };
+        write_to(name.0, text)
+    }
+
+    #[cfg(test)]
+    mod tests {
+        use super::*;
+        unsafe extern "C" {
+            fn PasteboardSynchronize(pasteboard: Object) -> u32;
+            fn PasteboardGetItemIdentifier(
+                pasteboard: Object,
+                index: isize,
+                item: *mut usize,
+            ) -> i32;
+            fn PasteboardCopyItemFlavorData(
+                pasteboard: Object,
+                item: usize,
+                flavor: Object,
+                data: *mut Object,
+            ) -> i32;
+            fn CFDataGetBytePtr(data: Object) -> *const u8;
+            fn CFDataGetLength(data: Object) -> isize;
+        }
+        #[test]
+        fn native_publication_preserves_plain_utf8_bytes_on_an_isolated_pasteboard() {
+            // A private pasteboard leaves the user's clipboard untouched.
+            let name = unsafe {
+                Owned::new(CFStringCreateWithCString(
+                    ptr::null(),
+                    c"vamp-native-clipboard-regression".as_ptr(),
+                    0x0800_0100,
+                ))
+                .unwrap()
+            };
+            let board = unsafe {
+                let mut board = ptr::null();
+                check(PasteboardCreate(name.0, &mut board)).unwrap();
+                Owned::new(board).unwrap()
+            };
+            for text in [
+                "",
+                "é e\u{301} 👨‍💻\n\0tail",
+                "{\\rtf1 plain text}",
+                "%!PS-Adobe-3.0\nplain",
+            ] {
+                write_to(name.0, text).unwrap();
+                unsafe {
+                    PasteboardSynchronize(board.0);
+                    let mut item = 0;
+                    check(PasteboardGetItemIdentifier(board.0, 1, &mut item)).unwrap();
+                    let flavor = Owned::new(CFStringCreateWithCString(
+                        ptr::null(),
+                        c"public.utf8-plain-text".as_ptr(),
+                        0x0800_0100,
+                    ))
+                    .unwrap();
+                    let mut data = ptr::null();
+                    check(PasteboardCopyItemFlavorData(
+                        board.0, item, flavor.0, &mut data,
+                    ))
+                    .unwrap();
+                    let data = Owned::new(data).unwrap();
+                    let length = CFDataGetLength(data.0) as usize;
+                    let bytes = if length == 0 {
+                        &[]
+                    } else {
+                        std::slice::from_raw_parts(CFDataGetBytePtr(data.0), length)
+                    };
+                    assert_eq!(bytes, text.as_bytes());
+                }
+            }
+        }
+    }
+}
+
 #[cfg(not(any(target_os = "macos", target_os = "linux")))]
 fn run(_: &ClipboardCommand, _: Option<&[u8]>, _: Duration) -> Result<Vec<u8>, String> {
    Err("System clipboard is unsupported on this platform".into())
@@ -514,6 +666,8 @@ mod tests {
            .as_mut()
            .unwrap()
            .writer
+            .as_mut()
+            .unwrap()
            .program = fixture.command(
            "noisy",
            &format!("/bin/dd if=/dev/zero bs=65536 count=8 >&2\nexec /bin/cat > {state}"),