fix: refresh diff colors on terminal theme changes

vendor/crossterm/src/ansi_support.rs

@@ -0,0 +1,46 @@
+use std::sync::atomic::{AtomicBool, Ordering};
+
+use crossterm_winapi::{ConsoleMode, Handle};
+use parking_lot::Once;
+use winapi::um::wincon::ENABLE_VIRTUAL_TERMINAL_PROCESSING;
+
+/// Enable virtual terminal processing.
+///
+/// This method attempts to enable virtual terminal processing for this
+/// console. If there was a problem enabling it, then an error returned.
+/// On success, the caller may assume that enabling it was successful.
+///
+/// When virtual terminal processing is enabled, characters emitted to the
+/// console are parsed for VT100 and similar control character sequences
+/// that control color and other similar operations.
+fn enable_vt_processing() -> std::io::Result<()> {
+    let mask = ENABLE_VIRTUAL_TERMINAL_PROCESSING;
+
+    let console_mode = ConsoleMode::from(Handle::current_out_handle()?);
+    let old_mode = console_mode.mode()?;
+
+    if old_mode & mask == 0 {
+        console_mode.set_mode(old_mode | mask)?;
+    }
+
+    Ok(())
+}
+
+static SUPPORTS_ANSI_ESCAPE_CODES: AtomicBool = AtomicBool::new(false);
+static INITIALIZER: Once = Once::new();
+
+/// Checks if the current terminal supports ANSI escape sequences
+pub fn supports_ansi() -> bool {
+    INITIALIZER.call_once(|| {
+        // Some terminals on Windows like GitBash can't use WinAPI calls directly
+        // so when we try to enable the ANSI-flag for Windows this won't work.
+        // Because of that we should check first if the TERM-variable is set
+        // and see if the current terminal is a terminal who does support ANSI.
+        let supported = enable_vt_processing().is_ok()
+            || std::env::var("TERM").map_or(false, |term| term != "dumb");
+
+        SUPPORTS_ANSI_ESCAPE_CODES.store(supported, Ordering::SeqCst);
+    });
+
+    SUPPORTS_ANSI_ESCAPE_CODES.load(Ordering::SeqCst)
+}