build/config/utility.cxx


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41

// file      : build/config/utility.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#include <build/config/utility>

using namespace std;

namespace build
{
  namespace config
  {
    // The same as the template except it is a bit more efficient
    // when it comes to not creating the default value string
    // unnecessarily.
    //
    pair<const string&, bool>
    required (scope& root, const char* name, const char* def_value)
    {
      string r;
      const variable& var (variable_pool.find (name));

      if (auto v = root[var])
      {
        const string& s (v.as<const string&> ());

        if (!v.belongs (*global_scope)) // A value from (some) config.build.
          return pair<const string&, bool> (s, false);

        r = s;
      }
      else
        r = def_value;

      auto v (root.assign (var));
      v = move (r);

      return pair<const string&, bool> (v.as<const string&> (), true);
    }
  }
}