feat: finish ghostty pane backend integration

1 files changed, 58 insertions, 0 deletions

diff --git a/vendor/libghostty-vt/src/input/keyboard.zig b/vendor/libghostty-vt/src/input/keyboard.zig
new file mode 100644
index 00000000..d2882a23
--- /dev/null
+++ b/vendor/libghostty-vt/src/input/keyboard.zig
@@ -0,0 +1,58 @@
+const std = @import("std");
+const OptionAsAlt = @import("config.zig").OptionAsAlt;
+
+/// Keyboard layouts.
+///
+/// These aren't heavily used in Ghostty and having a fully comprehensive
+/// list is not important. We only need to distinguish between a few
+/// different layouts for some nice-to-have features, such as setting a default
+/// value for "macos-option-as-alt".
+pub const Layout = enum {
+    // Unknown, unmapped layout. Ghostty should not make any assumptions
+    // about the layout of the keyboard.
+    unknown,
+
+    // The remaining should be fairly self-explanatory:
+    us_standard,
+    us_international,
+
+    /// Map an Apple keyboard layout ID to a value in this enum. The layout
+    /// ID can be retrieved using Carbon's TIKeyboardLayoutGetInputSourceProperty
+    /// function.
+    ///
+    /// Even though our layout supports "unknown", we return null if we don't
+    /// recognize the layout ID so callers can detect this scenario.
+    pub fn mapAppleId(id: []const u8) ?Layout {
+        if (std.mem.eql(u8, id, "com.apple.keylayout.US")) {
+            return .us_standard;
+        } else if (std.mem.eql(u8, id, "com.apple.keylayout.USInternational")) {
+            return .us_international;
+        }
+
+        return null;
+    }
+
+    /// Returns the default macos-option-as-alt value for this layout.
+    ///
+    /// We apply some heuristics to change the default based on the keyboard
+    /// layout if "macos-option-as-alt" is unset. We do this because on some
+    /// keyboard layouts such as US standard layouts, users generally expect
+    /// an input such as option-b to map to alt-b but macOS by default will
+    /// convert it to the codepoint "∫".
+    ///
+    /// This behavior however is desired on international layout where the
+    /// option key is used for important, regularly used inputs.
+    pub fn detectOptionAsAlt(self: Layout) OptionAsAlt {
+        return switch (self) {
+            // On US standard, the option key is typically used as alt
+            // and not as a modifier for other codepoints. For example,
+            // option-B = ∫ but usually the user wants alt-B.
+            .us_standard,
+            .us_international,
+            => .true,
+
+            .unknown,
+            => .false,
+        };
+    }
+};