first crack at adding SyncGuard from Funami580

Co-authored-by: Funami580 <63090225+Funami580@users.noreply.github.com>

Author: chris-laplante

src/lib.rs

@@ -78,7 +78,7 @@
 
 pub use crate::kb::Key;
 pub use crate::term::{
-    user_attended, user_attended_stderr, Term, TermFamily, TermFeatures, TermTarget,
+    user_attended, user_attended_stderr, SyncGuard, Term, TermFamily, TermFeatures, TermTarget,
 };
 pub use crate::utils::{
     colors_enabled, colors_enabled_stderr, measure_text_width, pad_str, pad_str_with,

src/term.rs

@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::fmt::{Debug, Display};
 use std::io::{self, Read, Write};
 use std::sync::{Arc, Mutex, RwLock};
@@ -78,6 +79,19 @@ impl<'a> TermFeatures<'a> {
         is_a_color_terminal(self.0)
     }
 
+    #[inline]
+    pub fn is_synchronized_output_supported(&self) -> bool {
+        #[cfg(unix)]
+        {
+            supports_synchronized_output()
+        }
+        #[cfg(not(unix))]
+        {
+            // TODO
+            false
+        }
+    }
+
     /// Check if this terminal is an msys terminal.
     ///
     /// This is sometimes useful to disable features that are known to not
@@ -656,6 +670,42 @@ impl<'a> Read for &'a Term {
     }
 }
 
+pub struct SyncGuard<'a> {
+    term: Cell<Option<&'a Term>>,
+}
+
+impl<'a> SyncGuard<'a> {
+    pub fn begin_sync(term: &'a Term) -> io::Result<Self> {
+        let ret = if term.features().is_synchronized_output_supported() {
+            term.write_str("\x1b[?2026h")?;
+            Some(term)
+        } else {
+            None
+        };
+
+        Ok(Self {
+            term: Cell::new(ret),
+        })
+    }
+
+    pub fn finish_sync(self) -> io::Result<()> {
+        self.finish_sync_inner()
+    }
+
+    fn finish_sync_inner(&self) -> io::Result<()> {
+        if let Some(term) = self.term.take() {
+            term.write_str("\x1b[?2026l")?;
+        }
+        Ok(())
+    }
+}
+
+impl Drop for SyncGuard<'_> {
+    fn drop(&mut self) {
+        let _ = self.finish_sync_inner();
+    }
+}
+
 #[cfg(all(unix, not(target_arch = "wasm32")))]
 pub use crate::unix_term::*;
 #[cfg(target_arch = "wasm32")]