Split build system into library and driver

1 files changed, 147 insertions, 0 deletions

diff --git a/libbuild2/module.cxx b/libbuild2/module.cxx
new file mode 100644
index 0000000..50530f2
--- /dev/null
+++ b/libbuild2/module.cxx
@@ -0,0 +1,147 @@
+// file      : libbuild2/module.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <libbuild2/module.hxx>
+
+#include <libbuild2/scope.hxx>
+#include <libbuild2/variable.hxx>
+#include <libbuild2/diagnostics.hxx>
+
+using namespace std;
+
+namespace build2
+{
+  available_module_map builtin_modules;
+
+  void
+  boot_module (scope& rs, const string& name, const location& loc)
+  {
+    // First see if this modules has already been loaded for this project.
+    //
+    loaded_module_map& lm (rs.root_extra->modules);
+    auto i (lm.find (name));
+
+    if (i != lm.end ())
+    {
+      module_state& s (i->second);
+
+      // The only valid situation here is if the module has already been
+      // bootstrapped.
+      //
+      assert (s.boot);
+      return;
+    }
+
+    // Otherwise search for this module.
+    //
+    auto j (builtin_modules.find (name));
+
+    if (j == builtin_modules.end ())
+      fail (loc) << "unknown module " << name;
+
+    const module_functions& mf (j->second);
+
+    if (mf.boot == nullptr)
+      fail (loc) << "module " << name << " shouldn't be loaded in bootstrap";
+
+    i = lm.emplace (name,
+                    module_state {true, false, mf.init, nullptr, loc}).first;
+    i->second.first = mf.boot (rs, loc, i->second.module);
+
+    rs.assign (var_pool.rw (rs).insert (name + ".booted")) = true;
+  }
+
+  bool
+  load_module (scope& rs,
+               scope& bs,
+               const string& name,
+               const location& loc,
+               bool opt,
+               const variable_map& hints)
+  {
+    // First see if this modules has already been loaded for this project.
+    //
+    loaded_module_map& lm (rs.root_extra->modules);
+    auto i (lm.find (name));
+    bool f (i == lm.end ());
+
+    if (f)
+    {
+      // Otherwise search for this module.
+      //
+      auto j (builtin_modules.find (name));
+
+      if (j == builtin_modules.end ())
+      {
+        if (!opt)
+          fail (loc) << "unknown module " << name;
+      }
+      else
+      {
+        const module_functions& mf (j->second);
+
+        if (mf.boot != nullptr)
+          fail (loc) << "module " << name << " should be loaded in bootstrap";
+
+        i = lm.emplace (
+          name,
+          module_state {false, false, mf.init, nullptr, loc}).first;
+      }
+    }
+    else
+    {
+      module_state& s (i->second);
+
+      if (s.boot)
+      {
+        s.boot = false;
+        f = true; // This is a first call to init.
+      }
+    }
+
+    // Note: pattern-typed in context.cxx:reset() as project-visibility
+    // variables of type bool.
+    //
+    auto& vp (var_pool.rw (rs));
+    value& lv (bs.assign (vp.insert (name + ".loaded")));
+    value& cv (bs.assign (vp.insert (name + ".configured")));
+
+    bool l; // Loaded.
+    bool c; // Configured.
+
+    // Suppress duplicate init() calls for the same module in the same scope.
+    //
+    if (!lv.null)
+    {
+      assert (!cv.null);
+
+      l = cast<bool> (lv);
+      c = cast<bool> (cv);
+
+      if (!opt)
+      {
+        if (!l)
+          fail (loc) << "unknown module " << name;
+
+        // We don't have original diagnostics. We could call init() again so
+        // that it can issue it. But that means optional modules must be
+        // prepared to be called again if configuring failed. Let's keep it
+        // simple for now.
+        //
+        if (!c)
+          fail (loc) << "module " << name << " failed to configure";
+      }
+    }
+    else
+    {
+      l = i != lm.end ();
+      c = l && i->second.init (rs, bs, loc, i->second.module, f, opt, hints);
+
+      lv = l;
+      cv = c;
+    }
+
+    return l && c;
+  }
+}