Function createEnvironFromExisting [src]

Creates a null-delimited environment variable block in the format expected by POSIX, from a hash map plus options.

Prototype

 pub fn createEnvironFromExisting( arena: Allocator, existing: [*:null]const ?[*:0]const u8, options: CreateEnvironOptions, ) Allocator.Error![:null]?[*:0]u8

Parameters

arena: Allocatorexisting: [*:null]const ?[*:0]const u8options: CreateEnvironOptions

Source

  pub fn createEnvironFromExisting(
    arena: Allocator,
    existing: [*:null]const ?[*:0]const u8,
    options: CreateEnvironOptions,
) Allocator.Error![:null]?[*:0]u8 {
    const existing_count, const contains_zig_progress = c: {
        var count: usize = 0;
        var contains = false;
        while (existing[count]) |line| : (count += 1) {
            contains = contains or mem.eql(u8, mem.sliceTo(line, '='), "ZIG_PROGRESS");
        }
        break :c .{ count, contains };
    };
    const ZigProgressAction = enum { nothing, edit, delete, add };
    const zig_progress_action: ZigProgressAction = a: {
        const fd = options.zig_progress_fd orelse break :a .nothing;
        if (fd >= 0) {
            break :a if (contains_zig_progress) .edit else .add;
        } else {
            if (contains_zig_progress) break :a .delete;
        }
        break :a .nothing;
    };

    const envp_count: usize = c: {
        var count: usize = existing_count;
        switch (zig_progress_action) {
            .add => count += 1,
            .delete => count -= 1,
            .nothing, .edit => {},
        }
        break :c count;
    };

    const envp_buf = try arena.allocSentinel(?[*:0]u8, envp_count, null);
    var i: usize = 0;
    var existing_index: usize = 0;

    if (zig_progress_action == .add) {
        envp_buf[i] = try std.fmt.allocPrintSentinel(arena, "ZIG_PROGRESS={d}", .{options.zig_progress_fd.?}, 0);
        i += 1;
    }

    while (existing[existing_index]) |line| : (existing_index += 1) {
        if (mem.eql(u8, mem.sliceTo(line, '='), "ZIG_PROGRESS")) switch (zig_progress_action) {
            .add => unreachable,
            .delete => continue,
            .edit => {
                envp_buf[i] = try std.fmt.allocPrintSentinel(arena, "ZIG_PROGRESS={d}", .{options.zig_progress_fd.?}, 0);
                i += 1;
                continue;
            },
            .nothing => {},
        };
        envp_buf[i] = try arena.dupeZ(u8, mem.span(line));
        i += 1;
    }

    assert(i == envp_count);
    return envp_buf;
}  