From 70120051c882c71f35c104fb469ea373535e4a34 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@jakstys.lt>
Date: Tue, 19 Apr 2022 10:29:14 +0300
Subject: [PATCH] members is a pointer now

---
 lib/DB.zig     | 46 +++++++++++++++++++++++-----------------------
 lib/cgroup.zig | 25 ++++---------------------
 2 files changed, 27 insertions(+), 44 deletions(-)

diff --git a/lib/DB.zig b/lib/DB.zig
index fa348d5..9b7f668 100644
--- a/lib/DB.zig
+++ b/lib/DB.zig
@@ -261,9 +261,9 @@ fn getGroup(
     buf.*[buf_offset + name.len] = 0;
 
     return CGroup{
-        .name = buf.*[buf_offset .. buf_offset + name.len].ptr,
         .gid = group.gid(),
-        .members = member_ptrs,
+        .name = buf.*[buf_offset .. buf_offset + name.len].ptr,
+        .members = member_ptrs.ptr,
     };
 }
 
@@ -602,28 +602,28 @@ test "high-level API" {
     var buf = try testing.allocator.alloc(u8, db.header.getgr_bufsize);
     defer testing.allocator.free(buf);
 
-    const all = try db.getgrnam("all", &buf);
-    try testing.expect(all != null);
-    try testing.expectEqual(all.?.gid, 9999);
-    try testing.expectEqualStrings(all.?.name[0..3], "all");
-    const members = all.?.members;
-    try testing.expectEqualStrings(mem.sliceTo(members[0].?, 0), "Name" ** 8);
-    try testing.expectEqualStrings(mem.sliceTo(members[1].?, 0), "root");
-    try testing.expectEqualStrings(mem.sliceTo(members[2].?, 0), "svc-bar");
-    try testing.expectEqualStrings(mem.sliceTo(members[3].?, 0), "vidmantas");
-    try testing.expectEqual(members[4], null);
+    {
+        const doesnotexist = try db.getgrnam("doesnotexist", &buf);
+        try testing.expectEqual(doesnotexist, null);
+        const all = (try db.getgrnam("all", &buf)).?;
+        try testing.expectEqual(all.gid, 9999);
+        try testing.expectEqualStrings(all.name[0..3], "all");
+        try testing.expectEqual(all.name[3], 0);
+        const members = all.members;
+        try testing.expectEqualStrings(mem.sliceTo(members[0].?, 0), "Name" ** 8);
+        try testing.expectEqualStrings(mem.sliceTo(members[1].?, 0), "root");
+        try testing.expectEqualStrings(mem.sliceTo(members[2].?, 0), "svc-bar");
+        try testing.expectEqualStrings(mem.sliceTo(members[3].?, 0), "vidmantas");
+        try testing.expectEqual(members[4], null);
+    }
 
-    const cgroup = all.?.ptr();
-    try testing.expectEqual(cgroup.gid, all.?.gid);
-    try testing.expectEqual(cgroup.name[0], 'a');
-    try testing.expectEqual(cgroup.name[1], 'l');
-    try testing.expectEqual(cgroup.name[2], 'l');
-    try testing.expectEqual(cgroup.name[3], 0);
-
-    const all_gid = try db.getgrgid(9999, &buf);
-    try testing.expect(all_gid != null);
-    try testing.expectEqual(all_gid.?.gid, 9999);
-    try testing.expectEqualStrings(all_gid.?.name[0..3], "all");
+    {
+        const doesnotexist = try db.getgrgid(42, &buf);
+        try testing.expectEqual(doesnotexist, null);
+        const all = (try db.getgrgid(9999, &buf)).?;
+        try testing.expectEqual(all.gid, 9999);
+        try testing.expectEqualStrings(all.name[0..3], "all");
+    }
 }
 
 test "getgr_bufsize" {
diff --git a/lib/cgroup.zig b/lib/cgroup.zig
index 569b123..bb98020 100644
--- a/lib/cgroup.zig
+++ b/lib/cgroup.zig
@@ -1,32 +1,15 @@
 const meta = @import("std").meta;
 
-// All string fields are 0-terminated, but that's not part of the type.
-// members field is null-terminated, but that's also not part of the type.
-// Making it part of the type crashes zig compiler in pre-0.10.
-// https://github.com/ziglang/zig/issues/7517
-
+// Name type should be 0-terminated, members should be null-terminated, but
+// sentinel is not part of the type (but is always there). Adding sentinel
+// crashes zig compiler in pre-0.10. https://github.com/ziglang/zig/issues/7517
 pub const CGroup = struct {
     gid: u32,
     // should be [*:0]const u8
     name: [*]const u8,
     // Should be [*:null]align(1) const ?[*:0]const u8
-    members: []align(1) const ?[*:0]const u8,
-
-    pub fn ptr(self: *const CGroup) CGroupPtr {
-        return CGroupPtr{
-            .gid = self.gid,
-            .name = self.name,
-            .members = @intToPtr([*]const u8, @ptrToInt(self.members.ptr)),
-        };
-    }
+    members: [*]align(1) const ?[*:0]const u8,
 };
 
 // size of the pointer to a single member.
 pub const ptr_size = @sizeOf(meta.Child(meta.fieldInfo(CGroup, .members).field_type));
-
-// a workaround of not having sentinel-terminated `name` and `members`.
-pub const CGroupPtr = extern struct {
-    gid: u32,
-    name: [*]const u8,
-    members: [*]const u8,
-};