mutate users in tests

src/user.zig

@@ -4,10 +4,11 @@ const pad = @import("padding.zig");
 const assert = std.debug.assert;
 const mem = std.mem;
 const Allocator = mem.Allocator;
+const ArrayList = std.ArrayList;
 
-// ShellIndexFn is a function prototype that, given a shell's index (in
+// Idx2ShellProto is a function prototype that, given a shell's index (in
-// global shell section), will return a shell string. Matches ShelReader.get.
+// global shell section), will return a shell string. Matches ShellReader.get.
-const ShellIndexFn = fn (u6) []const u8;
+const Idx2ShellProto = fn (u6) []const u8;
 
 // User is a convenient public struct for record construction and
 // serialization. Iterator can help retrieve these records.
@@ -28,19 +29,19 @@ fn packedUser(immutable: bool) type {
         const Self = @This();
 
         const AlignmentBits = 3;
-        const shellIndexFn = fn ([]const u8) ?u6;
+        const shell2idxProto = fn ([]const u8) ?u6;
 
         const InnerSize = @divExact(@bitSizeOf(Inner), 8);
         const Inner = packed struct {
             uid: u32,
             gid: u32,
-            additional_gids_offset: u29,
             shell_here: bool,
             shell_len_or_idx: u6,
             home_len: u6,
             name_is_a_suffix: bool,
             name_len: u5,
             gecos_len: u8,
+            additional_gids_offset: u29,
 
             fn homeLen(self: *const Inner) usize {
                 return @as(u32, self.home_len) + 1;
@@ -107,7 +108,7 @@ fn packedUser(immutable: bool) type {
         };
 
         pub fn fromBytes(bytes: Bytes) Entry {
-            const inner = std.mem.bytesAsValue(
+            const inner = mem.bytesAsValue(
                 Inner,
                 // Should use InnerSize instead of sizeOf, see
                 // https://github.com/ziglang/zig/issues/10958
@@ -154,7 +155,7 @@ fn packedUser(immutable: bool) type {
         pub fn packTo(
             arr: *ArrayList(u8),
             user: User,
-            idxFn: shellIndexFn,
+            idxFn: shell2idxProto,
         ) packErr!void {
             // function arguments are consts. We need to mutate the underlying
             // slice, so passing it via pointer instead.
@@ -219,6 +220,10 @@ fn packedUser(immutable: bool) type {
             return self.inner.gid;
         }
 
+        pub fn additionalGidsOffset(self: Self) u29 {
+            return self.inner.additional_gids_offset;
+        }
+
         pub fn home(self: Self) []const u8 {
             return self.userdata[0..self.inner.homeLen()];
         }
@@ -235,7 +240,7 @@ fn packedUser(immutable: bool) type {
             return self.userdata[gecos_pos .. gecos_pos + gecos_len];
         }
 
-        pub fn shell(self: Self, idxFn: ShellIndexFn) []const u8 {
+        pub fn shell(self: Self, idxFn: Idx2ShellProto) []const u8 {
             if (self.inner.shell_here) {
                 const shell_pos = self.inner.maybeShellStart();
                 const shell_len = self.inner.shellLen();
@@ -244,9 +249,17 @@ fn packedUser(immutable: bool) type {
             return idxFn(self.inner.shell_len_or_idx);
         }
 
+        pub fn setAdditionalGidsOffset(self: Self, new: u29) void {
+            // TODO(motiejus) how to not declare function for const PackedUser at all?
+            if (immutable) {
+                @compileError("this function is available only for mutable PackedUsers");
+            }
+            self.inner.additional_gids_offset = new;
+        }
+
         pub const Iterator = struct {
             section: ?Bytes,
-            shellIndex: ShellIndexFn,
+            shellIndex: Idx2ShellProto,
 
             pub fn next(it: *Iterator) ?Self {
                 if (it.section) |section| {
@@ -258,7 +271,7 @@ fn packedUser(immutable: bool) type {
             }
         };
 
-        pub fn iterator(section: Bytes, idxFn: ShellIndexFn) Iterator {
+        pub fn iterator(section: Bytes, idxFn: Idx2ShellProto) Iterator {
             return Iterator{
                 .section = section,
                 .shellIndex = idxFn,
@@ -268,7 +281,6 @@ fn packedUser(immutable: bool) type {
 }
 
 const testing = std.testing;
-const ArrayList = std.ArrayList;
 
 test "PackedUser internal and external alignment" {
     // External padding (AlignmentBits) must be higher or equal to
@@ -277,7 +289,7 @@ test "PackedUser internal and external alignment" {
     // cannot be converted from/to [@bitSizeOf(PackedUser)/8]u8;
     // asBytes/bytesAsValue use @sizeOf, which is larger. Now we are putting no
     // more than 1, but it probably could be higher.
-    try testing.expect(@sizeOf(PackedUserMut.Inner) * 8 - @bitSizeOf(PackedUserMut.Inner) <= 8);
+    try testing.expectEqual(8, @sizeOf(PackedUserConst.Inner) * 8 - @bitSizeOf(PackedUserConst.Inner));
 }
 
 fn testShellIndex(shell: []const u8) ?u6 {
@@ -331,21 +343,47 @@ test "construct PackedUser section" {
         .shell = "/",
     } };
     for (users) |user| {
-        try buf.ensureUnusedCapacity(PackedUserMut.maxSize());
+        try PackedUserConst.packTo(&buf, user, testShellIndex);
-        try PackedUserMut.packTo(&buf, user, testShellIndex);
     }
 
-    var it = PackedUserMut.iterator(buf.items, testShell);
+    var i: u29 = 0;
-    var i: u32 = 0;
+    {
+        var it = PackedUserConst.iterator(buf.items, testShell);
+        i = 0;
         while (it.next()) |user| : (i += 1) {
             try testing.expectEqual(users[i].uid, user.uid());
             try testing.expectEqual(users[i].gid, user.gid());
+            try testing.expectEqual(
+                @as(u29, std.math.maxInt(u29)),
+                user.additionalGidsOffset(),
+            );
             try testing.expectEqualStrings(users[i].name, user.name());
             try testing.expectEqualStrings(users[i].gecos, user.gecos());
             try testing.expectEqualStrings(users[i].home, user.home());
             try testing.expectEqualStrings(users[i].shell, user.shell(testShell));
         }
         try testing.expectEqual(users.len, i);
+    }
+
+    {
+        var it = PackedUserMut.iterator(buf.items, testShell);
+        i = 0;
+        while (it.next()) |user| : (i += 1) {
+            user.setAdditionalGidsOffset(i);
+        }
+        try testing.expectEqual(users.len, i);
+    }
+
+    {
+        var it = PackedUserConst.iterator(buf.items, testShell);
+        i = 0;
+        while (it.next()) |user| : (i += 1) {
+            try testing.expectEqual(users[i].gid, user.gid());
+            try testing.expectEqual(i, user.additionalGidsOffset());
+            try testing.expectEqualStrings(users[i].name, user.name());
+        }
+        try testing.expectEqual(users.len, i);
+    }
 }
 
 test "PackedUser.maxSize()" {