glfw: remove xcode_frameworks submodule; Sdk type

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

README.md

@@ -54,11 +54,7 @@ Then in your `build.zig` add:
 
 ```zig
 ...
-const glfw = @import("libs/mach-glfw/build.zig").Sdk(.{
+const glfw = @import("libs/mach-glfw/build.zig");
-    // TODO(build-system): This cannot be imported with the Zig package manager
-    // error: TarUnsupportedFileType
-    .xcode_frameworks = @import("libs/mach-glfw/libs/xcode-frameworks/build.zig"),
-});
 
 pub fn build(b: *Build) !void {
     ...

build.zig

@@ -6,19 +6,11 @@ pub fn build(b: *Build) !void {
     const optimize = b.standardOptimizeOption(.{});
     const target = b.standardTargetOptions(.{});
 
-    const glfw = Sdk(.{
-        // TODO(build-system): This cannot be imported with the Zig package manager
-        // error: TarUnsupportedFileType
-        .xcode_frameworks = @import("libs/xcode-frameworks/build.zig"),
-    });
-
     const test_step = b.step("test", "Run library tests");
-    test_step.dependOn(&(try glfw.testStep(b, optimize, target)).step);
+    test_step.dependOn(&(try testStep(b, optimize, target)).step);
-    test_step.dependOn(&(try glfw.testStepShared(b, optimize, target)).step);
+    test_step.dependOn(&(try testStepShared(b, optimize, target)).step);
 }
 
-pub fn Sdk(comptime deps: anytype) type {
-    return struct {
 pub fn testStep(b: *Build, optimize: std.builtin.OptimizeMode, target: std.zig.CrossTarget) !*std.build.RunStep {
     const main_tests = b.addTest(.{
         .name = "glfw-tests",
@@ -95,7 +87,7 @@ pub fn Sdk(comptime deps: anytype) type {
         //     .optimize = step.optimize,
         // }).artifact("xcode-frameworks"));
         // @import("xcode_frameworks").addPaths(step);
-                deps.xcode_frameworks.addPaths(step);
+        xcode_frameworks.addPaths(b, step);
     }
 }
 
@@ -204,7 +196,7 @@ pub fn Sdk(comptime deps: anytype) type {
         //     .optimize = step.optimize,
         // }).artifact("xcode-frameworks"));
         // @import("xcode_frameworks").addPaths(step);
-                deps.xcode_frameworks.addPaths(step);
+        xcode_frameworks.addPaths(b, step);
     }
     switch (step.target_info.target.os.tag) {
         .windows => {
@@ -262,5 +254,113 @@ pub fn Sdk(comptime deps: anytype) type {
         break :blk root_dir ++ suffix;
     };
 }
+
+// TODO(build-system): This is a workaround that we copy anywhere xcode_frameworks needs to be used.
+// With the Zig package manager, it should be possible to remove this entirely and instead just
+// write:
+//
+// ```
+// step.linkLibrary(b.dependency("xcode_frameworks", .{
+//     .target = step.target,
+//     .optimize = step.optimize,
+// }).artifact("xcode-frameworks"));
+// @import("xcode_frameworks").addPaths(step);
+// ```
+//
+// However, today this package cannot be imported with the Zig package manager due to `error: TarUnsupportedFileType`
+// which would be fixed by https://github.com/ziglang/zig/pull/15382 - so instead for now you must
+// copy+paste this struct into your `build.zig` and write:
+//
+// ```
+// try xcode_frameworks.addPaths(b, step);
+// ```
+const xcode_frameworks = struct {
+    pub fn addPaths(b: *std.Build, step: *std.build.CompileStep) void {
+        // branch: mach
+        ensureGitRepoCloned(b.allocator, "https://github.com/hexops/xcode-frameworks", "723aa55e9752c8c6c25d3413722b5fe13d72ac4f", "zig-cache/xcode_frameworks") catch |err| @panic(@errorName(err));
+
+        step.addFrameworkPath("zig-cache/xcode_frameworks/Frameworks");
+        step.addSystemIncludePath("zig-cache/xcode_frameworks/include");
+        step.addLibraryPath("zig-cache/xcode_frameworks/lib");
+    }
+
+    fn xcodeSdkPath(comptime suffix: []const u8) []const u8 {
+        if (suffix[0] != '/') @compileError("suffix must be an absolute path");
+        return comptime blk: {
+            const root_dir = std.fs.path.dirname(@src().file) orelse ".";
+            break :blk root_dir ++ suffix;
         };
     }
+
+    fn ensureGitRepoCloned(allocator: std.mem.Allocator, clone_url: []const u8, revision: []const u8, rel_dir: []const u8) !void {
+        if (isEnvVarTruthy(allocator, "NO_ENSURE_SUBMODULES") or isEnvVarTruthy(allocator, "NO_ENSURE_GIT")) {
+            return;
+        }
+
+        ensureGit(allocator);
+
+        if (std.fs.cwd().realpathAlloc(allocator, rel_dir)) |dir| {
+            const current_revision = try getCurrentGitRevision(allocator, dir);
+            if (!std.mem.eql(u8, current_revision, revision)) {
+                // Reset to the desired revision
+                exec(allocator, &[_][]const u8{ "git", "fetch" }, dir) catch |err| std.debug.print("warning: failed to 'git fetch' in {s}: {s}\n", .{ dir, @errorName(err) });
+                try exec(allocator, &[_][]const u8{ "git", "checkout", "--quiet", "--force", revision }, dir);
+                try exec(allocator, &[_][]const u8{ "git", "submodule", "update", "--init", "--recursive" }, dir);
+            }
+            return;
+        } else |err| return switch (err) {
+            error.FileNotFound => {
+                std.log.info("cloning required dependency..\ngit clone {s} {s}..\n", .{ clone_url, rel_dir });
+
+                try exec(allocator, &[_][]const u8{ "git", "clone", "-c", "core.longpaths=true", clone_url, rel_dir }, xcodeSdkPath("/"));
+                try exec(allocator, &[_][]const u8{ "git", "checkout", "--quiet", "--force", revision }, rel_dir);
+                try exec(allocator, &[_][]const u8{ "git", "submodule", "update", "--init", "--recursive" }, rel_dir);
+                return;
+            },
+            else => err,
+        };
+    }
+
+    fn exec(allocator: std.mem.Allocator, argv: []const []const u8, cwd: []const u8) !void {
+        var child = std.ChildProcess.init(argv, allocator);
+        child.cwd = cwd;
+        _ = try child.spawnAndWait();
+    }
+
+    fn getCurrentGitRevision(allocator: std.mem.Allocator, cwd: []const u8) ![]const u8 {
+        const result = try std.ChildProcess.exec(.{ .allocator = allocator, .argv = &.{ "git", "rev-parse", "HEAD" }, .cwd = cwd });
+        allocator.free(result.stderr);
+        if (result.stdout.len > 0) return result.stdout[0 .. result.stdout.len - 1]; // trim newline
+        return result.stdout;
+    }
+
+    fn ensureGit(allocator: std.mem.Allocator) void {
+        const argv = &[_][]const u8{ "git", "--version" };
+        const result = std.ChildProcess.exec(.{
+            .allocator = allocator,
+            .argv = argv,
+            .cwd = ".",
+        }) catch { // e.g. FileNotFound
+            std.log.err("mach: error: 'git --version' failed. Is git not installed?", .{});
+            std.process.exit(1);
+        };
+        defer {
+            allocator.free(result.stderr);
+            allocator.free(result.stdout);
+        }
+        if (result.term.Exited != 0) {
+            std.log.err("mach: error: 'git --version' failed. Is git not installed?", .{});
+            std.process.exit(1);
+        }
+    }
+
+    fn isEnvVarTruthy(allocator: std.mem.Allocator, name: []const u8) bool {
+        if (std.process.getEnvVarOwned(allocator, name)) |truthy| {
+            defer allocator.free(truthy);
+            if (std.mem.eql(u8, truthy, "true")) return true;
+            return false;
+        } else |_| {
+            return false;
+        }
+    }
+};