Move Utf-8 -> codepoint conversion to utils

Once we add more text to the bar, it makes sense to move this into a
helper function.

src/Bar.zig

@@ -224,17 +224,9 @@ pub fn draw(bar: *Bar) !void {
     var fbs = io.fixedBufferStream(&buf);
     try dt.strftime(fbs.writer(), "%H:%M");
 
-    // Convert ASCII text string to unicode
+    // Convert date string to Unicode codepoints
-    // XXX: Not sure if this even needs to be converted to unicode
+    const codepoints = try utils.utf8ToCodepoints(fbs.getWritten());
-    var codepoint_it = (try unicode.Utf8View.init(fbs.getWritten())).iterator();
-    const codepoint_count = try unicode.utf8CountCodepoints(fbs.getWritten());
-    // We use u32 for fcft even if zig uses u21
-    var codepoints: []u32 = try utils.gpa.alloc(u32, codepoint_count);
     defer utils.gpa.free(codepoints);
-    var i: usize = 0;
-    while (codepoint_it.nextCodepoint()) |cp| : (i += 1) {
-        codepoints[i] = cp;
-    }
 
     const text_width = try bar.textWidth(codepoints);
     var x: i32 = @divFloor(buffer.width - text_width, 2);
@@ -393,7 +385,6 @@ const assert = std.debug.assert;
 const io = std.io;
 const mem = std.mem;
 const process = std.process;
-const unicode = std.unicode;
 
 const wayland = @import("wayland");
 const wl = wayland.client.wl;

src/Window.zig

@@ -145,7 +145,7 @@ fn windowListener(river_window_v1: *river.WindowV1, event: river.WindowV1.Event,
                 while (it.next()) |seat| {
                     if (seat.focused_window == window) {
                         // Find another window to focus and warp pointer there
-                        if (output.prevWindow(window)) |next_focus| {
+                        if (output.nextWindow(window)) |next_focus| {
                             if (next_focus != window) {
                                 seat.pending_manage.window = .{ .window = next_focus };
                                 seat.pending_manage.should_warp_pointer = true;

src/utils.zig

@@ -193,6 +193,21 @@ pub fn stripQuotes(s: []const u8) []const u8 {
     return s;
 }
 
+/// Convert a Utf-8 string into codepoints
+/// Caller owns the returned slice and is responsible for freeing it.
+pub fn utf8ToCodepoints(utf8: []const u8) ![]u32 {
+    var codepoint_it = (try unicode.Utf8View.init(utf8)).iterator();
+    const codepoint_count = try unicode.utf8CountCodepoints(utf8);
+    // We use u32 for fcft even if zig uses u21
+    const codepoints: []u32 = try gpa.alloc(u32, codepoint_count);
+    var i: usize = 0;
+    while (codepoint_it.nextCodepoint()) |cp| : (i += 1) {
+        codepoints[i] = cp;
+    }
+
+    return codepoints;
+}
+
 /// Report that the given WaylandGlobal wasn't advertised and exit the program
 pub fn interfaceNotAdvertised(comptime WaylandGlobal: type) noreturn {
     fatal("{s} not advertised. Exiting", .{WaylandGlobal.interface.name});
@@ -207,6 +222,7 @@ const std = @import("std");
 const fatal = std.process.fatal;
 const fmt = std.fmt;
 const mem = std.mem;
+const unicode = std.unicode;
 
 const wayland = @import("wayland");
 const river = wayland.client.river;
@@ -447,3 +463,41 @@ test "tokenizeShell quotes mid-token" {
     try testing.expectEqual(1, result.len);
     try testing.expectEqualStrings("foobar bazqux", result[0]);
 }
+
+test "utf8ToCodepoints ASCII" {
+    const codepoints = try utf8ToCodepoints("hello");
+    defer gpa.free(codepoints);
+    try testing.expectEqual(5, codepoints.len);
+    try testing.expectEqual('h', codepoints[0]);
+    try testing.expectEqual('e', codepoints[1]);
+    try testing.expectEqual('l', codepoints[2]);
+    try testing.expectEqual('l', codepoints[3]);
+    try testing.expectEqual('o', codepoints[4]);
+}
+
+test "utf8ToCodepoints multi-byte" {
+    const codepoints = try utf8ToCodepoints("grüezi");
+    defer gpa.free(codepoints);
+    try testing.expectEqual(6, codepoints.len);
+    try testing.expectEqual('g', codepoints[0]);
+    try testing.expectEqual('r', codepoints[1]);
+    try testing.expectEqual(0x00FC, codepoints[2]); // ü
+    try testing.expectEqual('e', codepoints[3]);
+    try testing.expectEqual('z', codepoints[4]);
+    try testing.expectEqual('i', codepoints[5]);
+}
+
+test "utf8ToCodepoints empty" {
+    const codepoints = try utf8ToCodepoints("");
+    defer gpa.free(codepoints);
+    try testing.expectEqual(0, codepoints.len);
+}
+
+test "utf8ToCodepoints emoji" {
+    // 🇨🇦 is two regional indicator symbols: U+1F1E8 U+1F1E6
+    const codepoints = try utf8ToCodepoints("🇨🇦");
+    defer gpa.free(codepoints);
+    try testing.expectEqual(2, codepoints.len);
+    try testing.expectEqual(0x1F1E8, codepoints[0]);
+    try testing.expectEqual(0x1F1E6, codepoints[1]);
+}