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// file : build2/config/utility.txx -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <build2/scope>
#include <build2/context>
namespace build2
{
namespace config
{
template <typename T>
pair<reference_wrapper<const value>, bool>
required (scope& root, const variable& var, const T& def_val, bool def_ovr)
{
if (current_mif->id == configure_id)
save_variable (root, var);
pair<lookup, size_t> org (root.find_original (var));
lookup l (org.first);
bool n (false);
// The interaction with command line overrides can get tricky. For
// example, the override to defaul value could make (non-recursive)
// command line override in the outer scope no longer apply. So what we
// are going to do is first ignore overrides and perform the normal
// logic on the original. Then we apply the overrides on the result.
//
if (!l.defined () || (def_ovr && !l.belongs (root)))
{
l = lookup ((root.assign (var) = def_val), root);
org = make_pair (l, 1); // Lookup depth is 1 since in root.vars.
n = true;
}
if (var.override != nullptr)
{
pair<lookup, size_t> ovr (root.find_override (var, move (org)));
if (l != ovr.first) // Overriden?
{
l = move (ovr.first);
// Overriden and not inherited (same logic as in save_config()).
//
n = l.belongs (root) || l.belongs (*global_scope);
}
}
return pair<reference_wrapper<const value>, bool> (*l, n);
}
}
}
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