From d256d071e0dca88c7929aa018b22b66bbbae7dbd Mon Sep 17 00:00:00 2001
From: PiergiorgioZagaria <pgiorgio.zagaria@gmail.com>
Date: Wed, 27 Jul 2022 10:24:53 +0200
Subject: [PATCH] gamemode: WIP building gamemode from source

---
 build.zig                            |  5 ++--
 gamemode-zig/build.zig               | 34 ++++++++++++++++++++++++----
 gamemode-zig/c/common/build-config.h |  4 ++++
 3 files changed, 36 insertions(+), 7 deletions(-)
 create mode 100644 gamemode-zig/c/common/build-config.h

diff --git a/build.zig b/build.zig
index f6a5cf85..5d43ee29 100644
--- a/build.zig
+++ b/build.zig
@@ -230,8 +230,9 @@ pub const App = struct {
                 if (target.os.tag == .linux) {
                     exe.addPackage(gamemode.pkg);
                     // TODO: choose between system lib vs buildlib?
-                    gamemode.link(exe);
-                    // gamemode.buildAndLink(b, exe);
+                    gamemode.linkFromSystem(exe);
+                    // gamemode.linkFromSource(b, exe, .{});
+                    // gamemode.linkFromBinary(exe);
                 }
 
                 break :blk exe;
diff --git a/gamemode-zig/build.zig b/gamemode-zig/build.zig
index 256f721d..1af01996 100644
--- a/gamemode-zig/build.zig
+++ b/gamemode-zig/build.zig
@@ -1,32 +1,56 @@
 const std = @import("std");
+const LibExeObjStep = std.build.LibExeObjStep;
 
 pub const pkg = std.build.Pkg{
     .name = "gamemode",
     .source = .{ .path = thisDir() ++ "/src/gamemode.zig" },
 };
 
+pub const Options = struct {
+    libexecdir: []const u8 = "",
+    sysconfdir: []const u8 = "",
+    gamemode_version: []const u8 = "",
+
+    // Seems to be the only option the c files for libgamemode use
+    have_fn_pidfd_open: bool = true,
+};
+
 /// Link system library gamemode
-pub fn link(exe: *std.build.LibExeObjStep) void {
+pub fn linkFromSystem(exe: *LibExeObjStep) void {
     exe.linkSystemLibrary("gamemode");
 }
 
-// TODO: to build we still need to generate a config file called build_common.h
-// (see https://github.com/FeralInteractive/gamemode/blob/4dc99dff76218718763a6b07fc1900fa6d1dafd9/meson.build) line 151
-
 /// Build and link gamemode
-pub fn buildAndLink(b: *std.build.Builder, exe: *std.build.LibExeObjStep) void {
+pub fn linkFromSource(b: *std.build.Builder, exe: *LibExeObjStep, opts: Options) void {
+    var build_config = std.fs.createFileAbsolute((comptime thisDir()) ++ "/c/common/build-config.h", .{}) catch unreachable;
+    defer build_config.close();
+    const writer = build_config.writer();
+    writer.print(
+        \\#define LIBEXECDIR "{s}"
+        \\#define SYSCONFDIR "{s}"
+        \\#define GAMEMODE_VERSION "{s}"
+        \\#define HAVE_FN_PIDFD_OPEN {}
+    , .{ opts.libexecdir, opts.sysconfdir, opts.gamemode_version, @boolToInt(opts.have_fn_pidfd_open) }) catch unreachable;
+
     const lib_common = b.addStaticLibrary("common", null);
     lib_common.addCSourceFiles(&.{ (comptime thisDir()) ++ "/c/common/common-helpers.c", (comptime thisDir()) ++ "/c/common/common-pidfds.c" }, &.{});
+    lib_common.addIncludePath((comptime thisDir()) ++ "/c/common/");
     lib_common.linkLibC();
 
     const lib_gamemode = b.addSharedLibrarySource("gamemode", null, .unversioned);
     lib_gamemode.addCSourceFile((comptime thisDir()) ++ "/c/client_impl.c", &.{});
+    lib_gamemode.addIncludePath((comptime thisDir()) ++ "/c/common/");
     lib_gamemode.linkLibC();
+    lib_gamemode.linkSystemLibrary("dbus-1");
     lib_gamemode.linkLibrary(lib_common);
 
     exe.linkLibrary(lib_gamemode);
 }
 
+//  TODO:
+/// Build from provided shared library binary
+// pub fn linkFromBinary(exe: *LibExeObjStep) void {}
+
 fn thisDir() []const u8 {
     return std.fs.path.dirname(@src().file) orelse ".";
 }
diff --git a/gamemode-zig/c/common/build-config.h b/gamemode-zig/c/common/build-config.h
new file mode 100644
index 00000000..e311c300
--- /dev/null
+++ b/gamemode-zig/c/common/build-config.h
@@ -0,0 +1,4 @@
+#define LIBEXECDIR ""
+#define SYSCONFDIR ""
+#define GAMEMODE_VERSION ""
+#define HAVE_FN_PIDFD_OPEN 1
\ No newline at end of file