From a3696a918590d16f3191bda8774d1ebe4f85aaab Mon Sep 17 00:00:00 2001
From: cryptocode <cryptocode@zolo.io>
Date: Thu, 14 Sep 2023 14:53:31 +0200
Subject: [PATCH 1/4] Implement OSC 10 and OSC 11 default color queries

These OSC commands report the default foreground and background colors.

Most terminals return the RGB components scaled up to 16-bit components, because some
legacy software are unable to read 8-bit components. The PR follows this conventions.

iTerm2 allow 8-bit reporting through a config option, and a similar option is
added here. In addition to picking between scaled and unscaled reporting, the user
can also turn off OSC 10/11 replies altogether.

Scaling is essentially c / 1 * 65535, where c is the 8-bit component, and reporting
is left-padded with zeros if necessary. This format appears to stem from the XParseColor
format.
---
 src/config/Config.zig   | 23 ++++++++++
 src/terminal/Parser.zig |  2 +-
 src/terminal/osc.zig    | 95 +++++++++++++++++++++++++++++++++++++++++
 src/terminal/stream.zig |  6 +++
 src/termio/Exec.zig     | 52 ++++++++++++++++++++++
 5 files changed, 177 insertions(+), 1 deletion(-)

diff --git a/src/config/Config.zig b/src/config/Config.zig
index ff599e1ee..69827c4c3 100644
--- a/src/config/Config.zig
+++ b/src/config/Config.zig
@@ -305,6 +305,22 @@ keybind: Keybinds = .{},
 /// The default value is "detect".
 @"shell-integration": ShellIntegration = .detect,
 
+/// Sets the reporting format for OSC sequences that request color information.
+/// Ghostty currently supports OSC 10 (foreground) and OSC 11 (background) queries,
+/// and by default the reported values are scaled-up RGB values, where each component
+/// are 16 bits. This is how most terminals report these values. However, some legacy
+/// applications may require 8-bit, unscaled, components. We also support turning off
+/// reporting alltogether. The components are lowercase hex values.
+///
+/// Allowable values are:
+///
+///   * "none" - OSC 10/11 queries receive no reply
+///   * "bits8" - Color components are return unscaled, i.e. rr/gg/bb
+///   * "bits16" - Color components are returned scaled, e.g. rrrr/gggg/bbbb
+///
+/// The default value is "bits16".
+@"osc-color-report-format": OSCColorReportFormat = .bits16,
+
 /// If anything other than false, fullscreen mode on macOS will not use the
 /// native fullscreen, but make the window fullscreen without animations and
 /// using a new space. It's faster than the native fullscreen mode since it
@@ -1480,3 +1496,10 @@ pub const ShellIntegration = enum {
     fish,
     zsh,
 };
+
+/// OSC 10 and 11 default color reporting format.
+pub const OSCColorReportFormat = enum {
+    none,
+    bits8,
+    bits16,
+};
diff --git a/src/terminal/Parser.zig b/src/terminal/Parser.zig
index d376d5d10..1ddf2f55f 100644
--- a/src/terminal/Parser.zig
+++ b/src/terminal/Parser.zig
@@ -248,7 +248,7 @@ pub fn next(self: *Parser, c: u8) [3]?Action {
     return [3]?Action{
         // Exit depends on current state
         if (self.state == next_state) null else switch (self.state) {
-            .osc_string => if (self.osc_parser.end()) |cmd|
+            .osc_string => if (self.osc_parser.endWithStringTerminator(c)) |cmd|
                 Action{ .osc_dispatch = cmd }
             else
                 null,
diff --git a/src/terminal/osc.zig b/src/terminal/osc.zig
index f61504daf..dd05a0940 100644
--- a/src/terminal/osc.zig
+++ b/src/terminal/osc.zig
@@ -84,6 +84,7 @@ pub const Command = union(enum) {
         value: []const u8,
     },
 
+<<<<<<< HEAD
     /// OSC 22. Set the mouse shape. There doesn't seem to be a standard
     /// naming scheme for cursors but it looks like terminals such as Foot
     /// are moving towards using the W3C CSS cursor names. For OSC parsing,
@@ -91,6 +92,16 @@ pub const Command = union(enum) {
     mouse_shape: struct {
         value: []const u8,
     },
+
+    /// OSC 10 and OSC 11 default color report.
+    report_default_color: struct {
+        /// OSC 10 requests the foreground color, OSC 11 the background color.
+        kind: enum { foreground, background },
+
+        /// We must reply with the same string terminator (ST) as used in the
+        /// request. This is either ESC\ or BEL (0x07)
+        string_terminator: ?[]const u8 = null,
+    },
 };
 
 pub const Parser = struct {
@@ -134,6 +145,7 @@ pub const Parser = struct {
         // but the state space is small enough that we just build it up this way.
         @"0",
         @"1",
+        @"10",
         @"11",
         @"13",
         @"133",
@@ -143,6 +155,14 @@ pub const Parser = struct {
         @"52",
         @"7",
 
+        // OSC 10 is used to query the default foreground color, and to set the default foreground color.
+        // Only querying is currently supported.
+        osc_10,
+
+        // OSC 11 is used to query the default background color, and to set the default background color.
+        // Only querying is currently supported.
+        osc_11,
+
         // We're in a semantic prompt OSC command but we aren't sure
         // what the command is yet, i.e. `133;`
         semantic_prompt,
@@ -210,12 +230,23 @@ pub const Parser = struct {
             },
 
             .@"1" => switch (c) {
+                '0' => self.state = .@"10",
                 '1' => self.state = .@"11",
                 '3' => self.state = .@"13",
                 else => self.state = .invalid,
             },
 
+            .@"10" => switch (c) {
+                ';' => {
+                    self.state = .osc_10;
+                },
+                else => self.state = .invalid,
+            },
+
             .@"11" => switch (c) {
+                ';' => {
+                    self.state = .osc_11;
+                },
                 '2' => {
                     self.complete = true;
                     self.command = .{ .reset_cursor_color = {} };
@@ -303,6 +334,22 @@ pub const Parser = struct {
                 else => self.state = .invalid,
             },
 
+            .osc_10 => switch (c) {
+                '?' => {
+                    self.command = .{ .report_default_color = .{ .kind = .foreground } };
+                    self.complete = true;
+                },
+                else => self.state = .invalid,
+            },
+
+            .osc_11 => switch (c) {
+                '?' => {
+                    self.command = .{ .report_default_color = .{ .kind = .background } };
+                    self.complete = true;
+                },
+                else => self.state = .invalid,
+            },
+
             .semantic_prompt => switch (c) {
                 'A' => {
                     self.state = .semantic_option_start;
@@ -466,6 +513,24 @@ pub const Parser = struct {
 
         return self.command;
     }
+
+    /// End the sequence and return the command, if any. If the return value
+    /// is null, then no valid command was found. The provided `string_terminator`
+    /// character originates from the request. This way we can use the same
+    /// terminator in the reply, which would otherwise break applications that
+    /// don't consider both options.
+    pub fn endWithStringTerminator(self: *Parser, string_separator: u8) ?Command {
+        var maybe_cmd = self.end();
+        if (maybe_cmd) |*cmd| {
+            switch (cmd.*) {
+                .report_default_color => |*c| {
+                    c.string_terminator = if (string_separator == 0x07) "\x07" else "\x1b\\";
+                },
+                else => {},
+            }
+        }
+        return maybe_cmd;
+    }
 };
 
 test "OSC: change_window_title" {
@@ -697,3 +762,33 @@ test "OSC: longer than buffer" {
 
     try testing.expect(p.end() == null);
 }
+
+test "OSC: report default foreground color" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "10;?";
+    for (input) |ch| p.next(ch);
+
+    // This corresponds to ST = ESC \
+    const cmd = p.endWithStringTerminator('\x1b').?;
+    try testing.expect(cmd == .report_default_color);
+    try testing.expect(cmd.report_default_color.kind == .foreground);
+    try testing.expectEqualSlices(u8, cmd.report_default_color.string_terminator.?, "\x1b\\");
+}
+
+test "OSC: report default background color" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "11;?";
+    for (input) |ch| p.next(ch);
+
+    // This corresponds to ST = BELL
+    const cmd = p.endWithStringTerminator('\x07').?;
+    try testing.expect(cmd == .report_default_color);
+    try testing.expect(cmd.report_default_color.kind == .background);
+    try testing.expectEqualSlices(u8, cmd.report_default_color.string_terminator.?, "\x07");
+}
diff --git a/src/terminal/stream.zig b/src/terminal/stream.zig
index c12bc4063..5240b33b6 100644
--- a/src/terminal/stream.zig
+++ b/src/terminal/stream.zig
@@ -861,6 +861,12 @@ pub fn Stream(comptime Handler: type) type {
                     } else log.warn("unimplemented OSC callback: {}", .{cmd});
                 },
 
+                .report_default_color => |v| {
+                    if (@hasDecl(T, "reportDefaultColor")) {
+                        try self.handler.reportDefaultColor(if (v.kind == .foreground) "10" else "11", v.string_terminator);
+                    } else log.warn("unimplemented OSC callback: {}", .{cmd});
+                },
+
                 else => if (@hasDecl(T, "oscUnimplemented"))
                     try self.handler.oscUnimplemented(cmd)
                 else
diff --git a/src/termio/Exec.zig b/src/termio/Exec.zig
index 36deb1235..94deb6df5 100644
--- a/src/termio/Exec.zig
+++ b/src/termio/Exec.zig
@@ -68,6 +68,15 @@ grid_size: renderer.GridSize,
 default_cursor_style: terminal.Cursor.Style,
 default_cursor_blink: bool,
 
+/// Default foreground color for OSC 10 reporting.
+default_foreground_color: terminal.color.RGB,
+
+/// Default background color for OSC 11 reporting.
+default_background_color: terminal.color.RGB,
+
+/// The OSC 10/11 reply style.
+osc_color_report_format: configpkg.Config.OSCColorReportFormat,
+
 /// The data associated with the currently running thread.
 data: ?*EventData,
 
@@ -79,6 +88,9 @@ pub const DerivedConfig = struct {
     image_storage_limit: usize,
     cursor_style: terminal.Cursor.Style,
     cursor_blink: bool,
+    foreground: configpkg.Config.Color,
+    background: configpkg.Config.Color,
+    osc_color_report_format: configpkg.Config.OSCColorReportFormat,
 
     pub fn init(
         alloc_gpa: Allocator,
@@ -91,6 +103,9 @@ pub const DerivedConfig = struct {
             .image_storage_limit = config.@"image-storage-limit",
             .cursor_style = config.@"cursor-style",
             .cursor_blink = config.@"cursor-style-blink",
+            .foreground = config.foreground,
+            .background = config.background,
+            .osc_color_report_format = config.@"osc-color-report-format",
         };
     }
 
@@ -140,6 +155,9 @@ pub fn init(alloc: Allocator, opts: termio.Options) !Exec {
         .grid_size = opts.grid_size,
         .default_cursor_style = opts.config.cursor_style,
         .default_cursor_blink = opts.config.cursor_blink,
+        .default_foreground_color = config.foreground.toTerminalRGB(),
+        .default_background_color = config.background.toTerminalRGB(),
+        .osc_color_report_format = config.osc_color_report_format,
         .data = null,
     };
 }
@@ -204,6 +222,9 @@ pub fn threadEnter(self: *Exec, thread: *termio.Thread) !ThreadData {
                 .grid_size = &self.grid_size,
                 .default_cursor_style = self.default_cursor_style,
                 .default_cursor_blink = self.default_cursor_blink,
+                .default_foreground_color = self.default_foreground_color,
+                .default_background_color = self.default_background_color,
+                .osc_color_report_format = self.osc_color_report_format,
             },
         },
     };
@@ -1141,6 +1162,9 @@ const StreamHandler = struct {
     default_cursor: bool = true,
     default_cursor_style: terminal.Cursor.Style,
     default_cursor_blink: bool,
+    default_foreground_color: terminal.color.RGB,
+    default_background_color: terminal.color.RGB,
+    osc_color_report_format: configpkg.Config.OSCColorReportFormat,
 
     pub fn deinit(self: *StreamHandler) void {
         self.apc.deinit();
@@ -1779,4 +1803,32 @@ const StreamHandler = struct {
             self.ev.seen_title = false;
         }
     }
+
+    /// Implements OSC 10 and OSC 11, which reports default foreground and background color respectively.
+    pub fn reportDefaultColor(self: *StreamHandler, osc_code: []const u8, string_terminator: ?[]const u8) !void {
+        if (self.osc_color_report_format == .none) return;
+        var msg: termio.Message = .{ .write_small = .{} };
+
+        const resp = resp: {
+            if (self.osc_color_report_format == .bits16) {
+                break :resp try std.fmt.bufPrint(&msg.write_small.data, "\x1B]{s};rgb:{x:0>4}/{x:0>4}/{x:0>4}{s}", .{
+                    osc_code,
+                    @as(u16, self.default_foreground_color.r) * 257,
+                    @as(u16, self.default_foreground_color.g) * 257,
+                    @as(u16, self.default_foreground_color.b) * 257,
+                    if (string_terminator) |st| st else "\x1b\\",
+                });
+            } else {
+                break :resp try std.fmt.bufPrint(&msg.write_small.data, "\x1B]{s};rgb:{x:0>2}/{x:0>2}/{x:0>2}{s}", .{
+                    osc_code,
+                    @as(u16, self.default_foreground_color.r),
+                    @as(u16, self.default_foreground_color.g),
+                    @as(u16, self.default_foreground_color.b),
+                    if (string_terminator) |st| st else "\x1b\\",
+                });
+            }
+        };
+        msg.write_small.len = @intCast(resp.len);
+        self.messageWriter(msg);
+    }
 };

From dc14ca86ca5ba9f3ff698b8dbc5dc8de42ce67a2 Mon Sep 17 00:00:00 2001
From: cryptocode <cryptocode@zolo.io>
Date: Thu, 14 Sep 2023 21:14:23 +0200
Subject: [PATCH 2/4] Review updates:

* Change state names to more human readable query_default_fg/bg
* Single-line state prongs
* String terminator is not an enum
* Removed `endWithStringTerminator` and added nullabe arg to `end`
* Fixed a color reporting bug, fg/bg wasn't correctly picked
---
 src/terminal/Parser.zig |   2 +-
 src/terminal/osc.zig    | 104 ++++++++++++++++++----------------------
 src/terminal/stream.zig |   5 +-
 src/termio/Exec.zig     |  14 +++---
 4 files changed, 58 insertions(+), 67 deletions(-)

diff --git a/src/terminal/Parser.zig b/src/terminal/Parser.zig
index 1ddf2f55f..06b10e140 100644
--- a/src/terminal/Parser.zig
+++ b/src/terminal/Parser.zig
@@ -248,7 +248,7 @@ pub fn next(self: *Parser, c: u8) [3]?Action {
     return [3]?Action{
         // Exit depends on current state
         if (self.state == next_state) null else switch (self.state) {
-            .osc_string => if (self.osc_parser.endWithStringTerminator(c)) |cmd|
+            .osc_string => if (self.osc_parser.end(c)) |cmd|
                 Action{ .osc_dispatch = cmd }
             else
                 null,
diff --git a/src/terminal/osc.zig b/src/terminal/osc.zig
index dd05a0940..c49ef38a0 100644
--- a/src/terminal/osc.zig
+++ b/src/terminal/osc.zig
@@ -84,7 +84,6 @@ pub const Command = union(enum) {
         value: []const u8,
     },
 
-<<<<<<< HEAD
     /// OSC 22. Set the mouse shape. There doesn't seem to be a standard
     /// naming scheme for cursors but it looks like terminals such as Foot
     /// are moving towards using the W3C CSS cursor names. For OSC parsing,
@@ -99,8 +98,13 @@ pub const Command = union(enum) {
         kind: enum { foreground, background },
 
         /// We must reply with the same string terminator (ST) as used in the
-        /// request. This is either ESC\ or BEL (0x07)
-        string_terminator: ?[]const u8 = null,
+        /// request.
+        string_terminator: ?enum {
+            /// The preferred string terminator is ESC followed by \
+            st,
+            /// Some applications and terminals use BELL (0x07) as the string terminator.
+            bel,
+        } = null,
     },
 };
 
@@ -157,11 +161,11 @@ pub const Parser = struct {
 
         // OSC 10 is used to query the default foreground color, and to set the default foreground color.
         // Only querying is currently supported.
-        osc_10,
+        query_default_fg,
 
         // OSC 11 is used to query the default background color, and to set the default background color.
         // Only querying is currently supported.
-        osc_11,
+        query_default_bg,
 
         // We're in a semantic prompt OSC command but we aren't sure
         // what the command is yet, i.e. `133;`
@@ -237,16 +241,12 @@ pub const Parser = struct {
             },
 
             .@"10" => switch (c) {
-                ';' => {
-                    self.state = .osc_10;
-                },
+                ';' => self.state = .query_default_fg,
                 else => self.state = .invalid,
             },
 
             .@"11" => switch (c) {
-                ';' => {
-                    self.state = .osc_11;
-                },
+                ';' => self.state = .query_default_bg,
                 '2' => {
                     self.complete = true;
                     self.command = .{ .reset_cursor_color = {} };
@@ -334,7 +334,7 @@ pub const Parser = struct {
                 else => self.state = .invalid,
             },
 
-            .osc_10 => switch (c) {
+            .query_default_fg => switch (c) {
                 '?' => {
                     self.command = .{ .report_default_color = .{ .kind = .foreground } };
                     self.complete = true;
@@ -342,7 +342,7 @@ pub const Parser = struct {
                 else => self.state = .invalid,
             },
 
-            .osc_11 => switch (c) {
+            .query_default_bg => switch (c) {
                 '?' => {
                     self.command = .{ .report_default_color = .{ .kind = .background } };
                     self.complete = true;
@@ -497,7 +497,7 @@ pub const Parser = struct {
 
     /// End the sequence and return the command, if any. If the return value
     /// is null, then no valid command was found.
-    pub fn end(self: *Parser) ?Command {
+    pub fn end(self: *Parser, string_separator: ?u8) ?Command {
         if (!self.complete) {
             log.warn("invalid OSC command: {s}", .{self.buf[0..self.buf_idx]});
             return null;
@@ -511,25 +511,13 @@ pub const Parser = struct {
             else => {},
         }
 
-        return self.command;
-    }
-
-    /// End the sequence and return the command, if any. If the return value
-    /// is null, then no valid command was found. The provided `string_terminator`
-    /// character originates from the request. This way we can use the same
-    /// terminator in the reply, which would otherwise break applications that
-    /// don't consider both options.
-    pub fn endWithStringTerminator(self: *Parser, string_separator: u8) ?Command {
-        var maybe_cmd = self.end();
-        if (maybe_cmd) |*cmd| {
-            switch (cmd.*) {
-                .report_default_color => |*c| {
-                    c.string_terminator = if (string_separator == 0x07) "\x07" else "\x1b\\";
-                },
-                else => {},
-            }
+        switch (self.command) {
+            .report_default_color => |*c| {
+                c.string_terminator = if (string_separator == 0x07) .bel else .st;
+            },
+            else => {},
         }
-        return maybe_cmd;
+        return self.command;
     }
 };
 
@@ -541,7 +529,7 @@ test "OSC: change_window_title" {
     p.next(';');
     p.next('a');
     p.next('b');
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .change_window_title);
     try testing.expectEqualStrings("ab", cmd.change_window_title);
 }
@@ -554,7 +542,7 @@ test "OSC: change_window_title with 2" {
     p.next(';');
     p.next('a');
     p.next('b');
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .change_window_title);
     try testing.expectEqualStrings("ab", cmd.change_window_title);
 }
@@ -567,7 +555,7 @@ test "OSC: prompt_start" {
     const input = "133;A";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .prompt_start);
     try testing.expect(cmd.prompt_start.aid == null);
     try testing.expect(cmd.prompt_start.redraw);
@@ -581,7 +569,7 @@ test "OSC: prompt_start with single option" {
     const input = "133;A;aid=14";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .prompt_start);
     try testing.expectEqualStrings("14", cmd.prompt_start.aid.?);
 }
@@ -594,7 +582,7 @@ test "OSC: prompt_start with redraw disabled" {
     const input = "133;A;redraw=0";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .prompt_start);
     try testing.expect(!cmd.prompt_start.redraw);
 }
@@ -607,7 +595,7 @@ test "OSC: prompt_start with redraw invalid value" {
     const input = "133;A;redraw=42";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .prompt_start);
     try testing.expect(cmd.prompt_start.redraw);
     try testing.expect(cmd.prompt_start.kind == .primary);
@@ -621,7 +609,7 @@ test "OSC: prompt_start with continuation" {
     const input = "133;A;k=c";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .prompt_start);
     try testing.expect(cmd.prompt_start.kind == .continuation);
 }
@@ -634,7 +622,7 @@ test "OSC: end_of_command no exit code" {
     const input = "133;D";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .end_of_command);
 }
 
@@ -646,7 +634,7 @@ test "OSC: end_of_command with exit code" {
     const input = "133;D;25";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .end_of_command);
     try testing.expectEqual(@as(u8, 25), cmd.end_of_command.exit_code.?);
 }
@@ -659,7 +647,7 @@ test "OSC: prompt_end" {
     const input = "133;B";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .prompt_end);
 }
 
@@ -671,7 +659,7 @@ test "OSC: end_of_input" {
     const input = "133;C";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .end_of_input);
 }
 
@@ -683,7 +671,7 @@ test "OSC: reset_cursor_color" {
     const input = "112";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .reset_cursor_color);
 }
 
@@ -695,7 +683,7 @@ test "OSC: get/set clipboard" {
     const input = "52;s;?";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .clipboard_contents);
     try testing.expect(cmd.clipboard_contents.kind == 's');
     try testing.expect(std.mem.eql(u8, "?", cmd.clipboard_contents.data));
@@ -709,7 +697,7 @@ test "OSC: get/set clipboard (optional parameter)" {
     const input = "52;;?";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .clipboard_contents);
     try testing.expect(cmd.clipboard_contents.kind == 'c');
     try testing.expect(std.mem.eql(u8, "?", cmd.clipboard_contents.data));
@@ -723,7 +711,7 @@ test "OSC: report pwd" {
     const input = "7;file:///tmp/example";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .report_pwd);
     try testing.expect(std.mem.eql(u8, "file:///tmp/example", cmd.report_pwd.value));
 }
@@ -736,7 +724,7 @@ test "OSC: pointer cursor" {
     const input = "22;pointer";
     for (input) |ch| p.next(ch);
 
-    const cmd = p.end().?;
+    const cmd = p.end(null).?;
     try testing.expect(cmd == .mouse_shape);
     try testing.expect(std.mem.eql(u8, "pointer", cmd.mouse_shape.value));
 }
@@ -749,7 +737,7 @@ test "OSC: report pwd empty" {
     const input = "7;";
     for (input) |ch| p.next(ch);
 
-    try testing.expect(p.end() == null);
+    try testing.expect(p.end(null) == null);
 }
 
 test "OSC: longer than buffer" {
@@ -760,7 +748,7 @@ test "OSC: longer than buffer" {
     const input = "a" ** (Parser.MAX_BUF + 2);
     for (input) |ch| p.next(ch);
 
-    try testing.expect(p.end() == null);
+    try testing.expect(p.end(null) == null);
 }
 
 test "OSC: report default foreground color" {
@@ -771,11 +759,11 @@ test "OSC: report default foreground color" {
     const input = "10;?";
     for (input) |ch| p.next(ch);
 
-    // This corresponds to ST = ESC \
-    const cmd = p.endWithStringTerminator('\x1b').?;
+    // This corresponds to ST = ESC followed by \
+    const cmd = p.end('\x1b').?;
     try testing.expect(cmd == .report_default_color);
-    try testing.expect(cmd.report_default_color.kind == .foreground);
-    try testing.expectEqualSlices(u8, cmd.report_default_color.string_terminator.?, "\x1b\\");
+    try testing.expectEqual(cmd.report_default_color.kind, .foreground);
+    try testing.expectEqual(cmd.report_default_color.string_terminator, .st);
 }
 
 test "OSC: report default background color" {
@@ -786,9 +774,9 @@ test "OSC: report default background color" {
     const input = "11;?";
     for (input) |ch| p.next(ch);
 
-    // This corresponds to ST = BELL
-    const cmd = p.endWithStringTerminator('\x07').?;
+    // This corresponds to ST = BEL character
+    const cmd = p.end('\x07').?;
     try testing.expect(cmd == .report_default_color);
-    try testing.expect(cmd.report_default_color.kind == .background);
-    try testing.expectEqualSlices(u8, cmd.report_default_color.string_terminator.?, "\x07");
+    try testing.expectEqual(cmd.report_default_color.kind, .background);
+    try testing.expectEqual(cmd.report_default_color.string_terminator.?, .bel);
 }
diff --git a/src/terminal/stream.zig b/src/terminal/stream.zig
index 5240b33b6..79d02a8e8 100644
--- a/src/terminal/stream.zig
+++ b/src/terminal/stream.zig
@@ -863,7 +863,10 @@ pub fn Stream(comptime Handler: type) type {
 
                 .report_default_color => |v| {
                     if (@hasDecl(T, "reportDefaultColor")) {
-                        try self.handler.reportDefaultColor(if (v.kind == .foreground) "10" else "11", v.string_terminator);
+                        try self.handler.reportDefaultColor(
+                            if (v.kind == .foreground) "10" else "11",
+                            if (v.string_terminator == .st) "\x1b\\" else "\x07",
+                        );
                     } else log.warn("unimplemented OSC callback: {}", .{cmd});
                 },
 
diff --git a/src/termio/Exec.zig b/src/termio/Exec.zig
index 94deb6df5..453673761 100644
--- a/src/termio/Exec.zig
+++ b/src/termio/Exec.zig
@@ -1808,22 +1808,22 @@ const StreamHandler = struct {
     pub fn reportDefaultColor(self: *StreamHandler, osc_code: []const u8, string_terminator: ?[]const u8) !void {
         if (self.osc_color_report_format == .none) return;
         var msg: termio.Message = .{ .write_small = .{} };
-
+        const color = if (std.mem.eql(u8, osc_code, "10")) self.default_foreground_color else self.default_background_color;
         const resp = resp: {
             if (self.osc_color_report_format == .bits16) {
                 break :resp try std.fmt.bufPrint(&msg.write_small.data, "\x1B]{s};rgb:{x:0>4}/{x:0>4}/{x:0>4}{s}", .{
                     osc_code,
-                    @as(u16, self.default_foreground_color.r) * 257,
-                    @as(u16, self.default_foreground_color.g) * 257,
-                    @as(u16, self.default_foreground_color.b) * 257,
+                    @as(u16, color.r) * 257,
+                    @as(u16, color.g) * 257,
+                    @as(u16, color.b) * 257,
                     if (string_terminator) |st| st else "\x1b\\",
                 });
             } else {
                 break :resp try std.fmt.bufPrint(&msg.write_small.data, "\x1B]{s};rgb:{x:0>2}/{x:0>2}/{x:0>2}{s}", .{
                     osc_code,
-                    @as(u16, self.default_foreground_color.r),
-                    @as(u16, self.default_foreground_color.g),
-                    @as(u16, self.default_foreground_color.b),
+                    @as(u16, color.r),
+                    @as(u16, color.g),
+                    @as(u16, color.b),
                     if (string_terminator) |st| st else "\x1b\\",
                 });
             }

From 19ef4a22a950474a25b5dbbc14e26126c2707e8e Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 14 Sep 2023 13:12:41 -0700
Subject: [PATCH 3/4] terminal: stylistic changes for OSC terminators, 10/11
 params

---
 src/terminal/main.zig   |  1 +
 src/terminal/osc.zig    | 65 ++++++++++++++++++++++++++++++++---------
 src/terminal/stream.zig |  5 +---
 src/termio/Exec.zig     | 46 +++++++++++++++++++----------
 4 files changed, 84 insertions(+), 33 deletions(-)

diff --git a/src/terminal/main.zig b/src/terminal/main.zig
index 3de1835d9..23b032daf 100644
--- a/src/terminal/main.zig
+++ b/src/terminal/main.zig
@@ -6,6 +6,7 @@ const ansi = @import("ansi.zig");
 const csi = @import("csi.zig");
 const sgr = @import("sgr.zig");
 pub const apc = @import("apc.zig");
+pub const osc = @import("osc.zig");
 pub const point = @import("point.zig");
 pub const color = @import("color.zig");
 pub const kitty = @import("kitty.zig");
diff --git a/src/terminal/osc.zig b/src/terminal/osc.zig
index c49ef38a0..03d3baf99 100644
--- a/src/terminal/osc.zig
+++ b/src/terminal/osc.zig
@@ -95,17 +95,53 @@ pub const Command = union(enum) {
     /// OSC 10 and OSC 11 default color report.
     report_default_color: struct {
         /// OSC 10 requests the foreground color, OSC 11 the background color.
-        kind: enum { foreground, background },
+        kind: DefaultColorKind,
 
         /// We must reply with the same string terminator (ST) as used in the
         /// request.
-        string_terminator: ?enum {
-            /// The preferred string terminator is ESC followed by \
-            st,
-            /// Some applications and terminals use BELL (0x07) as the string terminator.
-            bel,
-        } = null,
+        terminator: Terminator = .st,
     },
+
+    pub const DefaultColorKind = enum {
+        foreground,
+        background,
+
+        pub fn code(self: DefaultColorKind) []const u8 {
+            return switch (self) {
+                .foreground => "10",
+                .background => "11",
+            };
+        }
+    };
+};
+
+/// The terminator used to end an OSC command. For OSC commands that demand
+/// a response, we try to match the terminator used in the request since that
+/// is most likely to be accepted by the calling program.
+pub const Terminator = enum {
+    /// The preferred string terminator is ESC followed by \
+    st,
+
+    /// Some applications and terminals use BELL (0x07) as the string terminator.
+    bel,
+
+    /// Initialize the terminator based on the last byte seen. If the
+    /// last byte is a BEL then we use BEL, otherwise we just assume ST.
+    pub fn init(ch: ?u8) Terminator {
+        return switch (ch orelse return .st) {
+            0x07 => .bel,
+            else => .st,
+        };
+    }
+
+    /// The terminator as a string. This is static memory so it doesn't
+    /// need to be freed.
+    pub fn string(self: Terminator) []const u8 {
+        return switch (self) {
+            .st => "\x1b\\",
+            .bel => "\x07",
+        };
+    }
 };
 
 pub const Parser = struct {
@@ -496,8 +532,10 @@ pub const Parser = struct {
     }
 
     /// End the sequence and return the command, if any. If the return value
-    /// is null, then no valid command was found.
-    pub fn end(self: *Parser, string_separator: ?u8) ?Command {
+    /// is null, then no valid command was found. The optional terminator_ch
+    /// is the final character in the OSC sequence. This is used to determine
+    /// the response terminator.
+    pub fn end(self: *Parser, terminator_ch: ?u8) ?Command {
         if (!self.complete) {
             log.warn("invalid OSC command: {s}", .{self.buf[0..self.buf_idx]});
             return null;
@@ -512,11 +550,10 @@ pub const Parser = struct {
         }
 
         switch (self.command) {
-            .report_default_color => |*c| {
-                c.string_terminator = if (string_separator == 0x07) .bel else .st;
-            },
+            .report_default_color => |*c| c.terminator = Terminator.init(terminator_ch),
             else => {},
         }
+
         return self.command;
     }
 };
@@ -763,7 +800,7 @@ test "OSC: report default foreground color" {
     const cmd = p.end('\x1b').?;
     try testing.expect(cmd == .report_default_color);
     try testing.expectEqual(cmd.report_default_color.kind, .foreground);
-    try testing.expectEqual(cmd.report_default_color.string_terminator, .st);
+    try testing.expectEqual(cmd.report_default_color.terminator, .st);
 }
 
 test "OSC: report default background color" {
@@ -778,5 +815,5 @@ test "OSC: report default background color" {
     const cmd = p.end('\x07').?;
     try testing.expect(cmd == .report_default_color);
     try testing.expectEqual(cmd.report_default_color.kind, .background);
-    try testing.expectEqual(cmd.report_default_color.string_terminator.?, .bel);
+    try testing.expectEqual(cmd.report_default_color.terminator, .bel);
 }
diff --git a/src/terminal/stream.zig b/src/terminal/stream.zig
index 79d02a8e8..824d08ffa 100644
--- a/src/terminal/stream.zig
+++ b/src/terminal/stream.zig
@@ -863,10 +863,7 @@ pub fn Stream(comptime Handler: type) type {
 
                 .report_default_color => |v| {
                     if (@hasDecl(T, "reportDefaultColor")) {
-                        try self.handler.reportDefaultColor(
-                            if (v.kind == .foreground) "10" else "11",
-                            if (v.string_terminator == .st) "\x1b\\" else "\x07",
-                        );
+                        try self.handler.reportDefaultColor(v.kind, v.terminator);
                     } else log.warn("unimplemented OSC callback: {}", .{cmd});
                 },
 
diff --git a/src/termio/Exec.zig b/src/termio/Exec.zig
index 453673761..8dec213d2 100644
--- a/src/termio/Exec.zig
+++ b/src/termio/Exec.zig
@@ -1804,29 +1804,45 @@ const StreamHandler = struct {
         }
     }
 
-    /// Implements OSC 10 and OSC 11, which reports default foreground and background color respectively.
-    pub fn reportDefaultColor(self: *StreamHandler, osc_code: []const u8, string_terminator: ?[]const u8) !void {
+    /// Implements OSC 10 and OSC 11, which reports default foreground and
+    /// background color respectively.
+    pub fn reportDefaultColor(
+        self: *StreamHandler,
+        kind: terminal.osc.Command.DefaultColorKind,
+        terminator: terminal.osc.Terminator,
+    ) !void {
         if (self.osc_color_report_format == .none) return;
+
+        const color = switch (kind) {
+            .foreground => self.default_foreground_color,
+            .background => self.default_background_color,
+        };
+
         var msg: termio.Message = .{ .write_small = .{} };
-        const color = if (std.mem.eql(u8, osc_code, "10")) self.default_foreground_color else self.default_background_color;
-        const resp = resp: {
-            if (self.osc_color_report_format == .bits16) {
-                break :resp try std.fmt.bufPrint(&msg.write_small.data, "\x1B]{s};rgb:{x:0>4}/{x:0>4}/{x:0>4}{s}", .{
-                    osc_code,
+        const resp = switch (self.osc_color_report_format) {
+            .bits16 => try std.fmt.bufPrint(
+                &msg.write_small.data,
+                "\x1B]{s};rgb:{x:0>4}/{x:0>4}/{x:0>4}{s}",
+                .{
+                    kind.code(),
                     @as(u16, color.r) * 257,
                     @as(u16, color.g) * 257,
                     @as(u16, color.b) * 257,
-                    if (string_terminator) |st| st else "\x1b\\",
-                });
-            } else {
-                break :resp try std.fmt.bufPrint(&msg.write_small.data, "\x1B]{s};rgb:{x:0>2}/{x:0>2}/{x:0>2}{s}", .{
-                    osc_code,
+                    terminator.string(),
+                },
+            ),
+
+            else => try std.fmt.bufPrint(
+                &msg.write_small.data,
+                "\x1B]{s};rgb:{x:0>2}/{x:0>2}/{x:0>2}{s}",
+                .{
+                    kind.code(),
                     @as(u16, color.r),
                     @as(u16, color.g),
                     @as(u16, color.b),
-                    if (string_terminator) |st| st else "\x1b\\",
-                });
-            }
+                    terminator.string(),
+                },
+            ),
         };
         msg.write_small.len = @intCast(resp.len);
         self.messageWriter(msg);

From 14724290d8fed2dd32dbb657662bb932649b694b Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Thu, 14 Sep 2023 13:15:09 -0700
Subject: [PATCH 4/4] config: change osc-color-report-format enum

---
 src/config/Config.zig | 12 ++++++------
 src/termio/Exec.zig   |  6 ++++--
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/config/Config.zig b/src/config/Config.zig
index 69827c4c3..b5e4340dd 100644
--- a/src/config/Config.zig
+++ b/src/config/Config.zig
@@ -315,11 +315,11 @@ keybind: Keybinds = .{},
 /// Allowable values are:
 ///
 ///   * "none" - OSC 10/11 queries receive no reply
-///   * "bits8" - Color components are return unscaled, i.e. rr/gg/bb
-///   * "bits16" - Color components are returned scaled, e.g. rrrr/gggg/bbbb
+///   * "8-bit" - Color components are return unscaled, i.e. rr/gg/bb
+///   * "16-bit" - Color components are returned scaled, e.g. rrrr/gggg/bbbb
 ///
-/// The default value is "bits16".
-@"osc-color-report-format": OSCColorReportFormat = .bits16,
+/// The default value is "16-bit".
+@"osc-color-report-format": OSCColorReportFormat = .@"16-bit",
 
 /// If anything other than false, fullscreen mode on macOS will not use the
 /// native fullscreen, but make the window fullscreen without animations and
@@ -1500,6 +1500,6 @@ pub const ShellIntegration = enum {
 /// OSC 10 and 11 default color reporting format.
 pub const OSCColorReportFormat = enum {
     none,
-    bits8,
-    bits16,
+    @"8-bit",
+    @"16-bit",
 };
diff --git a/src/termio/Exec.zig b/src/termio/Exec.zig
index 8dec213d2..06911050a 100644
--- a/src/termio/Exec.zig
+++ b/src/termio/Exec.zig
@@ -1820,7 +1820,7 @@ const StreamHandler = struct {
 
         var msg: termio.Message = .{ .write_small = .{} };
         const resp = switch (self.osc_color_report_format) {
-            .bits16 => try std.fmt.bufPrint(
+            .@"16-bit" => try std.fmt.bufPrint(
                 &msg.write_small.data,
                 "\x1B]{s};rgb:{x:0>4}/{x:0>4}/{x:0>4}{s}",
                 .{
@@ -1832,7 +1832,7 @@ const StreamHandler = struct {
                 },
             ),
 
-            else => try std.fmt.bufPrint(
+            .@"8-bit" => try std.fmt.bufPrint(
                 &msg.write_small.data,
                 "\x1B]{s};rgb:{x:0>2}/{x:0>2}/{x:0>2}{s}",
                 .{
@@ -1843,6 +1843,8 @@ const StreamHandler = struct {
                     terminator.string(),
                 },
             ),
+
+            .none => unreachable, // early return above
         };
         msg.write_small.len = @intCast(resp.len);
         self.messageWriter(msg);