From 52520d04ef66375bfd861842a1ff9552dadfae9b Mon Sep 17 00:00:00 2001
From: Stephen Gutekanst <stephen@hexops.com>
Date: Tue, 16 Aug 2022 20:12:25 -0700
Subject: [PATCH] gpu: improve type naming for next_in_chain extension types

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
---
 gpu/README.md                 |  2 +-
 gpu/examples/sample_utils.zig |  6 +++---
 gpu/src/shader_module.zig     | 14 +++++++-------
 gpu/src/surface.zig           | 26 +++++++++++++-------------
 4 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/gpu/README.md b/gpu/README.md
index 5fdfcb54..7eebd593 100644
--- a/gpu/README.md
+++ b/gpu/README.md
@@ -218,7 +218,7 @@ Here `gpu.Surface.Descriptor` is a concrete type. The `next_in_chain` field is s
 Complexity aside, `next_in_chain` is not type safe! It cannot be, because such an extension could be implementation-specific. To make this safer, we instead change the `next_in_chain` field type to be a union, where one option is the type-unsafe `generic` pointer, and the other options are known extensions:
 
 ```zig
-pub const Extension = extern union {
+pub const NextInChain = extern union {
     generic: ?*const ChainedStruct,
     from_windows_hwnd: *const DescriptorFromWindowsHWND,
     // ...
diff --git a/gpu/examples/sample_utils.zig b/gpu/examples/sample_utils.zig
index 270c563d..19dd2e72 100644
--- a/gpu/examples/sample_utils.zig
+++ b/gpu/examples/sample_utils.zig
@@ -170,12 +170,12 @@ pub fn createSurfaceForWindow(
     comptime glfw_options: glfw.BackendOptions,
 ) *gpu.Surface {
     const glfw_native = glfw.Native(glfw_options);
-    const extension = if (glfw_options.win32) gpu.Surface.Extension{
+    const extension = if (glfw_options.win32) gpu.Surface.Descriptor.NextInChain{
         .from_windows_hwnd = &.{
             .hinstance = std.os.windows.kernel32.GetModuleHandleW(null).?,
             .hwnd = glfw_native.getWin32Window(window),
         },
-    } else if (glfw_options.x11) gpu.Surface.Extension{
+    } else if (glfw_options.x11) gpu.Surface.Descriptor.NextInChain{
         .from_xlib_window = &.{
             .display = glfw_native.getX11Display(),
             .window = glfw_native.getX11Window(window),
@@ -194,7 +194,7 @@ pub fn createSurfaceForWindow(
         const scale_factor = msgSend(ns_window, "backingScaleFactor", .{}, f64); // [ns_window backingScaleFactor]
         msgSend(layer.?, "setContentsScale:", .{scale_factor}, void); // [layer setContentsScale:scale_factor]
 
-        break :blk gpu.Surface.Extension{ .from_metal_layer = &.{ .layer = layer.? } };
+        break :blk gpu.Surface.Descriptor.NextInChain{ .from_metal_layer = &.{ .layer = layer.? } };
     } else if (glfw_options.wayland) {
         @panic("TODO: this example does not support Wayland");
     } else unreachable;
diff --git a/gpu/src/shader_module.zig b/gpu/src/shader_module.zig
index b2fd7561..8dc1b259 100644
--- a/gpu/src/shader_module.zig
+++ b/gpu/src/shader_module.zig
@@ -5,14 +5,14 @@ const CompilationInfo = @import("types.zig").CompilationInfo;
 const Impl = @import("interface.zig").Impl;
 
 pub const ShaderModule = opaque {
-    pub const Extension = extern union {
-        generic: ?*const ChainedStruct,
-        spirv_descriptor: ?*const SPIRVDescriptor,
-        wgsl_descriptor: ?*const WGSLDescriptor,
-    };
-
     pub const Descriptor = extern struct {
-        next_in_chain: Extension = .{ .generic = null },
+        pub const NextInChain = extern union {
+            generic: ?*const ChainedStruct,
+            spirv_descriptor: ?*const SPIRVDescriptor,
+            wgsl_descriptor: ?*const WGSLDescriptor,
+        };
+
+        next_in_chain: NextInChain = .{ .generic = null },
         label: ?[*:0]const u8 = null,
     };
 
diff --git a/gpu/src/surface.zig b/gpu/src/surface.zig
index 8452dab1..ad8d4b1a 100644
--- a/gpu/src/surface.zig
+++ b/gpu/src/surface.zig
@@ -2,20 +2,20 @@ const ChainedStruct = @import("types.zig").ChainedStruct;
 const Impl = @import("interface.zig").Impl;
 
 pub const Surface = opaque {
-    pub const Extension = extern union {
-        generic: ?*const ChainedStruct,
-        from_android_native_window: *const DescriptorFromAndroidNativeWindow,
-        from_canvas_html_selector: *const DescriptorFromCanvasHTMLSelector,
-        from_metal_layer: *const DescriptorFromMetalLayer,
-        from_wayland_surface: *const DescriptorFromWaylandSurface,
-        from_windows_core_window: *const DescriptorFromWindowsCoreWindow,
-        from_windows_hwnd: *const DescriptorFromWindowsHWND,
-        from_windows_swap_chain_panel: *const DescriptorFromWindowsSwapChainPanel,
-        from_xlib_window: *const DescriptorFromXlibWindow,
-    };
-
     pub const Descriptor = extern struct {
-        next_in_chain: Extension = .{ .generic = null },
+        pub const NextInChain = extern union {
+            generic: ?*const ChainedStruct,
+            from_android_native_window: *const DescriptorFromAndroidNativeWindow,
+            from_canvas_html_selector: *const DescriptorFromCanvasHTMLSelector,
+            from_metal_layer: *const DescriptorFromMetalLayer,
+            from_wayland_surface: *const DescriptorFromWaylandSurface,
+            from_windows_core_window: *const DescriptorFromWindowsCoreWindow,
+            from_windows_hwnd: *const DescriptorFromWindowsHWND,
+            from_windows_swap_chain_panel: *const DescriptorFromWindowsSwapChainPanel,
+            from_xlib_window: *const DescriptorFromXlibWindow,
+        };
+
+        next_in_chain: NextInChain = .{ .generic = null },
         label: ?[*:0]const u8 = null,
     };