build info

1 files changed, 31 insertions, 0 deletions

diff --git a/build.zig b/build.zig
index 9ceae7f..ebde0a2 100644
--- a/build.zig
+++ b/build.zig
@@ -1,6 +1,9 @@
 const std = @import("std");
 const builtin = @import("builtin");
 
+const HEAD_location = ".git/HEAD";
+const commit_location = ".git/refs/heads/master";
+
 pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
@@ -11,6 +14,11 @@ pub fn build(b: *std.Build) void {
         .link_libc = true,
     });
 
+    
+    // Adding a build version
+
+    root.addCMacro("BUILD_VERSION", GetVersionString(b, optimize) catch "Build UNTRACKED");
+
     root.addCSourceFiles(.{
         .files = &[_][]const u8 {
             "src/main.c",
@@ -62,3 +70,26 @@ pub fn build(b: *std.Build) void {
         run_cmd.addArgs(args);
     }
 }
+
+// Returns a build version. Returns an empty string if build in release mode
+fn GetVersionString(b: *std.Build, optimization: std.builtin.OptimizeMode) ![]u8 {
+    if (optimization != .Debug) {
+        return "";
+    }
+
+    const allocator = b.allocator;
+    var threaded = std.Io.Threaded.init(allocator, .{});
+    defer threaded.deinit();
+
+    const headContents = try std.Io.Dir.cwd().readFileAlloc(threaded.io(), HEAD_location, allocator, .limited(std.math.maxInt(usize)));
+    var headIter = std.mem.tokenizeAny(u8, headContents[0..headContents.len - 1], "/");
+    var branchName: []const u8 = "";
+    while (headIter.next()) |token| {
+        branchName = token;
+    }
+    const commitContents = try std.Io.Dir.cwd().readFileAlloc(threaded.io(), commit_location, allocator, .limited(std.math.maxInt(usize)));
+    return try std.fmt.allocPrint(allocator, "\"Build {s}:{s}\"", .{
+        branchName,
+        commitContents[0..@min(commitContents.len-1, 10)]
+    });
+}