1const std = @import("std");
 2const testing = std.testing;
 3const builtin = @import("builtin");
 4const common = @import("common.zig");
 5const panic = @import("common.zig").panic;
 6
 7const have_availability_version_check = builtin.os.tag.isDarwin() and
 8    builtin.os.version_range.semver.min.order(.{ .major = 10, .minor = 15, .patch = 0 }).compare(.gte);
 9
10comptime {
11    if (have_availability_version_check) {
12        @export(&__isPlatformVersionAtLeast, .{ .name = "__isPlatformVersionAtLeast", .linkage = common.linkage, .visibility = common.visibility });
13    }
14}
15
16// Ported from llvm-project 13.0.0 d7b669b3a30345cfcdb2fde2af6f48aa4b94845d
17//
18// https://github.com/llvm/llvm-project/blob/llvmorg-13.0.0/compiler-rt/lib/builtins/os_version_check.c
19
20// The compiler generates calls to __isPlatformVersionAtLeast() when Objective-C's @available
21// function is invoked.
22//
23// Old versions of clang would instead emit calls to __isOSVersionAtLeast(), which is still
24// supported in clang's compiler-rt implementation today in case anyone tries to link an object file
25// produced with an old clang version. This requires dynamically loading frameworks, parsing a
26// system plist file, and generally adds a fair amount of complexity to the implementation and so
27// our implementation differs by simply removing that backwards compatability support. We only use
28// the newer codepath, which merely calls out to the Darwin _availability_version_check API which is
29// available on macOS 10.15+, iOS 13+, tvOS 13+ and watchOS 6+.
30
31const __isPlatformVersionAtLeast = if (have_availability_version_check) struct {
32    inline fn constructVersion(major: u32, minor: u32, subminor: u32) u32 {
33        return ((major & 0xffff) << 16) | ((minor & 0xff) << 8) | (subminor & 0xff);
34    }
35
36    // Darwin-only
37    fn __isPlatformVersionAtLeast(platform: u32, major: u32, minor: u32, subminor: u32) callconv(.c) i32 {
38        const build_version = dyld_build_version_t{
39            .platform = platform,
40            .version = constructVersion(major, minor, subminor),
41        };
42        return @intFromBool(_availability_version_check(1, &[_]dyld_build_version_t{build_version}));
43    }
44
45    // _availability_version_check darwin API support.
46    const dyld_platform_t = u32;
47    const dyld_build_version_t = extern struct {
48        platform: dyld_platform_t,
49        version: u32,
50    };
51    // Darwin-only
52    extern "c" fn _availability_version_check(count: u32, versions: [*c]const dyld_build_version_t) bool;
53}.__isPlatformVersionAtLeast else struct {};
54
55test "isPlatformVersionAtLeast" {
56    if (!have_availability_version_check) return error.SkipZigTest;
57
58    // Note: this test depends on the actual host OS version since it is merely calling into the
59    // native Darwin API.
60    const macos_platform_constant = 1;
61    try testing.expect(__isPlatformVersionAtLeast(macos_platform_constant, 10, 0, 15) == 1);
62    try testing.expect(__isPlatformVersionAtLeast(macos_platform_constant, 99, 0, 0) == 0);
63}