From 70fae468c26175ffe38bf65fb69ca8e360c959cf Mon Sep 17 00:00:00 2001
From: dweiller <4678790+dweiller@users.noreply.github.com>
Date: Sat, 20 Jul 2024 03:34:14 +1000
Subject: [PATCH] add XDG base directory spec support

---
 build.zig | 19 ++++++++++++++++---
 zigup.zig | 37 ++++++++++++++++++++++++++++++-------
 2 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/build.zig b/build.zig
index cd1cd7b..b8f4f1e 100644
--- a/build.zig
+++ b/build.zig
@@ -5,8 +5,17 @@ pub fn build(b: *std.Build) !void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
+    const use_xdg = b.option(
+        bool,
+        "use-xdg",
+        "Use the XDG base directory specification (default: false)",
+    ) orelse false;
+
+    const build_options = b.addOptions();
+    build_options.addOption(bool, "use_xdg", use_xdg);
+
     const zigup_exe_native = blk: {
-        const exe = addZigupExe(b, target, optimize);
+        const exe = addZigupExe(b, target, optimize, build_options);
         b.installArtifact(exe);
         const run_cmd = b.addRunArtifact(exe);
         run_cmd.step.dependOn(b.getInstallStep());
@@ -74,13 +83,14 @@ pub fn build(b: *std.Build) !void {
     ci_step.dependOn(test_step);
     ci_step.dependOn(unzip_step);
     ci_step.dependOn(zip_step);
-    try ci(b, ci_step, test_step, host_zip_exe);
+    try ci(b, ci_step, test_step, host_zip_exe, build_options);
 }
 
 fn addZigupExe(
     b: *std.Build,
     target: std.Build.ResolvedTarget,
     optimize: std.builtin.Mode,
+    build_options: *std.Build.Step.Options,
 ) *std.Build.Step.Compile {
     const win32exelink_mod: ?*std.Build.Module = blk: {
         if (target.result.os.tag == .windows) {
@@ -104,6 +114,8 @@ fn addZigupExe(
         .optimize = optimize,
     });
 
+    exe.root_module.addOptions("build-options", build_options);
+
     if (target.result.os.tag == .windows) {
         exe.root_module.addImport("win32exelink", win32exelink_mod.?);
     }
@@ -115,6 +127,7 @@ fn ci(
     ci_step: *std.Build.Step,
     test_step: *std.Build.Step,
     host_zip_exe: *std.Build.Step.Compile,
+    build_options: *std.Build.Step.Options,
 ) !void {
     const ci_targets = [_][]const u8{
         "x86_64-linux",
@@ -140,7 +153,7 @@ fn ci(
         const optimize: std.builtin.OptimizeMode =
             // Compile in ReleaseSafe on Windows for faster extraction
             if (target.result.os.tag == .windows) .ReleaseSafe else .Debug;
-        const zigup_exe = addZigupExe(b, target, optimize);
+        const zigup_exe = addZigupExe(b, target, optimize, build_options);
         const zigup_exe_install = b.addInstallArtifact(zigup_exe, .{
             .dest_dir = .{ .override = .{ .custom = ci_target_str } },
         });
diff --git a/zigup.zig b/zigup.zig
index f7a60b8..6208eca 100644
--- a/zigup.zig
+++ b/zigup.zig
@@ -2,6 +2,8 @@ const std = @import("std");
 const builtin = @import("builtin");
 const mem = std.mem;
 
+const build_options = @import("build-options");
+
 const ArrayList = std.ArrayList;
 const Allocator = mem.Allocator;
 
@@ -119,10 +121,15 @@ fn ignoreHttpCallback(request: []const u8) void {
 }
 
 fn getHomeDir() ![]const u8 {
-    return std.posix.getenv("HOME") orelse {
+    const home = std.posix.getenv("HOME") orelse {
         std.log.err("cannot find install directory, $HOME environment variable is not set", .{});
-        return error.MissingHomeEnvironmentVariable;
+        return error.AlreadyReported;
     };
+    if (!std.fs.path.isAbsolute(home)) {
+        std.log.err("$HOME environment variable '{s}' is not an absolute path", .{home});
+        return error.AlreadyReported;
+    }
+    return home;
 }
 
 fn allocInstallDirString(allocator: Allocator) ![]const u8 {
@@ -133,12 +140,28 @@ fn allocInstallDirString(allocator: Allocator) ![]const u8 {
         defer allocator.free(self_exe_dir);
         return std.fs.path.join(allocator, &.{ self_exe_dir, "zig" });
     }
-    const home = try getHomeDir();
-    if (!std.fs.path.isAbsolute(home)) {
-        std.log.err("$HOME environment variable '{s}' is not an absolute path", .{home});
-        return error.BadHomeEnvironmentVariable;
+
+    if (build_options.use_xdg) {
+        if (std.posix.getenv("XDG_DATA_HOME")) |xdg_data_home| {
+            if (xdg_data_home.len > 0) {
+                if (!std.fs.path.isAbsolute(xdg_data_home)) {
+                    std.log.err(
+                        "$XDG_DATA_HOME environment variable '{s}' is not an absolute path",
+                        .{xdg_data_home},
+                    );
+                    return error.AlreadyReported;
+                }
+                return std.fs.path.join(allocator, &.{ xdg_data_home, "zigup" });
+            }
+        }
+        const sep = .{std.fs.path.sep};
+        return std.fs.path.join(allocator, &.{
+            try getHomeDir(), ".local" ++ sep ++ "share" ++ sep ++ "zigup",
+        });
     }
-    return std.fs.path.join(allocator, &[_][]const u8{ home, "zig" });
+    return std.fs.path.join(allocator, &[_][]const u8{
+        try getHomeDir(), "zig",
+    });
 }
 const GetInstallDirOptions = struct {
     create: bool,