From 482edf4a10bb79e64e5fedf8c0db6ce35caf24b0 Mon Sep 17 00:00:00 2001
From: "Jeffrey C. Ollie" <jeff@ocjtech.us>
Date: Fri, 3 Jan 2025 15:44:55 -0600
Subject: [PATCH] core: function to detect the display type

---
 src/cli/version.zig | 37 +++++++++++++++++++------------------
 src/os/desktop.zig  | 27 +++++++++++++++++++++++++++
 src/os/main.zig     |  1 +
 3 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/src/cli/version.zig b/src/cli/version.zig
index 99f03384b..5607619f9 100644
--- a/src/cli/version.zig
+++ b/src/cli/version.zig
@@ -27,46 +27,47 @@ pub fn run(alloc: Allocator) !u8 {
     if (tty) try stdout.print("\x1b]8;;\x1b\\", .{});
 
     try stdout.print("Version\n", .{});
-    try stdout.print("  - version: {s}\n", .{build_config.version_string});
-    try stdout.print("  - channel: {s}\n", .{@tagName(build_config.release_channel)});
+    try stdout.print("  - version     : {s}\n", .{build_config.version_string});
+    try stdout.print("  - channel     : {s}\n", .{@tagName(build_config.release_channel)});
 
     try stdout.print("Build Config\n", .{});
-    try stdout.print("  - Zig version: {s}\n", .{builtin.zig_version_string});
-    try stdout.print("  - build mode : {}\n", .{builtin.mode});
-    try stdout.print("  - app runtime: {}\n", .{build_config.app_runtime});
-    try stdout.print("  - font engine: {}\n", .{build_config.font_backend});
-    try stdout.print("  - renderer   : {}\n", .{renderer.Renderer});
-    try stdout.print("  - libxev     : {}\n", .{xev.backend});
+    try stdout.print("  - Zig version : {s}\n", .{builtin.zig_version_string});
+    try stdout.print("  - build mode  : {}\n", .{builtin.mode});
+    try stdout.print("  - app runtime : {}\n", .{build_config.app_runtime});
+    try stdout.print("  - font engine : {}\n", .{build_config.font_backend});
+    try stdout.print("  - renderer    : {}\n", .{renderer.Renderer});
+    try stdout.print("  - libxev      : {}\n", .{xev.backend});
     if (comptime build_config.app_runtime == .gtk) {
-        try stdout.print("  - desktop env: {s}\n", .{@tagName(internal_os.desktopEnvironment())});
-        try stdout.print("  - GTK version:\n", .{});
-        try stdout.print("    build      : {d}.{d}.{d}\n", .{
+        try stdout.print("  - desktop env : {s}\n", .{@tagName(internal_os.desktopEnvironment())});
+        try stdout.print("  - display type: {s}\n", .{@tagName(internal_os.displayType())});
+        try stdout.print("  - GTK version :\n", .{});
+        try stdout.print("    build       : {d}.{d}.{d}\n", .{
             gtk.GTK_MAJOR_VERSION,
             gtk.GTK_MINOR_VERSION,
             gtk.GTK_MICRO_VERSION,
         });
-        try stdout.print("    runtime    : {d}.{d}.{d}\n", .{
+        try stdout.print("    runtime     : {d}.{d}.{d}\n", .{
             gtk.gtk_get_major_version(),
             gtk.gtk_get_minor_version(),
             gtk.gtk_get_micro_version(),
         });
         if (comptime build_options.adwaita) {
-            try stdout.print("  - libadwaita : enabled\n", .{});
-            try stdout.print("    build      : {s}\n", .{
+            try stdout.print("  - libadwaita  : enabled\n", .{});
+            try stdout.print("    build       : {s}\n", .{
                 gtk.ADW_VERSION_S,
             });
-            try stdout.print("    runtime    : {}.{}.{}\n", .{
+            try stdout.print("    runtime     : {}.{}.{}\n", .{
                 gtk.adw_get_major_version(),
                 gtk.adw_get_minor_version(),
                 gtk.adw_get_micro_version(),
             });
         } else {
-            try stdout.print("  - libadwaita : disabled\n", .{});
+            try stdout.print("  - libadwaita  : disabled\n", .{});
         }
         if (comptime build_options.x11) {
-            try stdout.print("  - libX11     : enabled\n", .{});
+            try stdout.print("  - libX11      : enabled\n", .{});
         } else {
-            try stdout.print("  - libX11     : disabled\n", .{});
+            try stdout.print("  - libX11      : disabled\n", .{});
         }
     }
     return 0;
diff --git a/src/os/desktop.zig b/src/os/desktop.zig
index 3a61e2eaa..46f3da375 100644
--- a/src/os/desktop.zig
+++ b/src/os/desktop.zig
@@ -85,3 +85,30 @@ pub fn desktopEnvironment() DesktopEnvironment {
         else => .other,
     };
 }
+
+pub const DisplayType = enum {
+    macos,
+    other,
+    wayland,
+    windows,
+    x11,
+};
+
+/// Detect what desktop environment we are running under. This is mainly used on
+/// Linux to enable or disable GTK client-side decorations but there may be more
+/// uses in the future.
+pub fn displayType() DisplayType {
+    return switch (comptime builtin.os.tag) {
+        .macos => .macos,
+        .windows => .windows,
+        .linux => dt: {
+            if (@inComptime()) @compileError("Checking for the display type on Linux must be done at runtime.");
+            // use $XDG_SESSION_TYPE to determine what display type we are using on Linux
+            const dt = posix.getenv("XDG_SESSION_TYPE") orelse break :dt .other;
+            if (std.ascii.eqlIgnoreCase("wayland", dt)) break :dt .wayland;
+            if (std.ascii.eqlIgnoreCase("x11", dt)) break :dt .x11;
+            break :dt .other;
+        },
+        else => .other,
+    };
+}
diff --git a/src/os/main.zig b/src/os/main.zig
index e652a7981..7b79de79f 100644
--- a/src/os/main.zig
+++ b/src/os/main.zig
@@ -33,6 +33,7 @@ pub const setenv = env.setenv;
 pub const unsetenv = env.unsetenv;
 pub const launchedFromDesktop = desktop.launchedFromDesktop;
 pub const desktopEnvironment = desktop.desktopEnvironment;
+pub const displayType = desktop.displayType;
 pub const rlimit = file.rlimit;
 pub const fixMaxFiles = file.fixMaxFiles;
 pub const restoreMaxFiles = file.restoreMaxFiles;