WIP

Author: habedi

.github/workflows/zig-master.yml

@@ -1,9 +1,5 @@
 name: Zig Master Canary
 
-# Early-warning build against the Zig master toolchain. A failure here does not block anything;
-# it signals upcoming breakage (std API churn, bundled Clang changes, dependency build.zig incompatibilities)
-# months before the next Zig release forces an upgrade.
-
 on:
   workflow_dispatch:
   schedule: # Run every Monday at 06:00 (UTC)

build.zig.zon

@@ -9,8 +9,8 @@
             .hash = "minish-0.3.0-SQtSTYI3AgCxWdWbKxS_lvmfbp0wJk29ZW5C9CozJaxm",
         },
         .chilli = .{
-            .url = "https://github.com/CogitatorTech/chilli/archive/refs/tags/v0.3.1.tar.gz",
-            .hash = "chilli-0.3.1-c19PrjizAQByQrJlXzEb8SrMY6cDJyWaZ9FnxFfN0kYl",
+            .url = "https://github.com/CogitatorTech/chilli/archive/refs/tags/v0.3.2.tar.gz",
+            .hash = "chilli-0.3.2-c19PrireAQAXEfA7xrmJW2lrSiNiuuG8wtJI-MJVZgFU",
         },
         .zsdl = .{
             .url = "https://github.com/zig-gamedev/zsdl/archive/100f46b336a112497436144e14877118573e0adf.tar.gz",

src/platform.zig

@@ -77,15 +77,17 @@ pub const File = struct {
         return self.f.writer(io(), buffer);
     }
 
+    // std.Io.File exposes no public seek wrappers (only positional reads and
+    // writes), so go through the Io vtable, which implements seeking for
+    // every supported OS.
     pub fn seekTo(self: File, offset: u64) !void {
-        const rc = std.os.linux.lseek(self.f.handle, @intCast(offset), std.os.linux.SEEK.SET);
-        if (std.os.linux.errno(rc) != .SUCCESS) return error.Unseekable;
+        const i = io();
+        return i.vtable.fileSeekTo(i.userdata, self.f, offset);
     }
 
-    pub fn getPos(self: File) !u64 {
-        const rc = std.os.linux.lseek(self.f.handle, 0, std.os.linux.SEEK.CUR);
-        if (std.os.linux.errno(rc) != .SUCCESS) return error.Unseekable;
-        return rc;
+    pub fn seekBy(self: File, offset: i64) !void {
+        const i = io();
+        return i.vtable.fileSeekBy(i.userdata, self.f, offset);
     }
 
     pub fn readToEndAlloc(self: File, allocator: std.mem.Allocator, max_bytes: usize) ![]u8 {
@@ -97,6 +99,28 @@ pub const File = struct {
     }
 };
 
+test "File seekTo and seekBy reposition the stream" {
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+
+    var file = try (Dir{ .d = tmp.dir }).createFile("seek.bin", .{ .read = true });
+    defer file.close();
+    try file.writeAll("abcdef");
+
+    try file.seekTo(1);
+    var buf: [2]u8 = undefined;
+    try std.testing.expectEqual(@as(usize, 2), try file.readAll(buf[0..2]));
+    try std.testing.expectEqualSlices(u8, "bc", buf[0..2]);
+
+    try file.seekBy(-1);
+    try std.testing.expectEqual(@as(usize, 1), try file.readAll(buf[0..1]));
+    try std.testing.expectEqual(@as(u8, 'c'), buf[0]);
+
+    try file.seekTo(0);
+    try std.testing.expectEqual(@as(usize, 1), try file.readAll(buf[0..1]));
+    try std.testing.expectEqual(@as(u8, 'a'), buf[0]);
+}
+
 pub fn stdout() File {
     return .{ .f = std.Io.File.stdout() };
 }

src/recording/gif.zig

@@ -66,8 +66,8 @@ pub const GifRecorder = struct {
         if (framebuffer.len < stride * (height - 1) + width) return error.InvalidFrameSize;
 
         if (self.frame_count > 0) {
-            const pos = self.file.getPos() catch 0;
-            if (pos > 0) self.file.seekTo(pos - 1) catch {};
+            // Step back over the GIF trailer byte so the new frame overwrites it.
+            self.file.seekBy(-1) catch {};
         }
 
         var palette: [max_colors]u32 = [_]u32{0} ** max_colors;

src/unit_test_root.zig

@@ -39,6 +39,7 @@ const frontend_saves = @import("frontend/saves.zig");
 const input_gamepad = @import("input/gamepad.zig");
 const input_keyboard = @import("input/keyboard.zig");
 const libretro = @import("libretro.zig");
+const platform_mod = @import("platform.zig");
 
 comptime {
     _ = audio_blip_buf;
@@ -82,4 +83,5 @@ comptime {
     _ = input_gamepad;
     _ = input_keyboard;
     _ = libretro;
+    _ = platform_mod;
 }