Cache project name in root_extra

5 files changed, 55 insertions, 19 deletions

diff --git a/libbuild2/file.cxx b/libbuild2/file.cxx
index e0467ad..4431bd1 100644
--- a/libbuild2/file.cxx
+++ b/libbuild2/file.cxx
@@ -497,6 +497,7 @@ namespace build2
 
     root.root_extra.reset (
       new scope::root_extra_type {
+        nullopt /* project */,
         nullopt /* amalgamation */,
         a,
         a ? alt_build_ext        : std_build_ext,
@@ -646,8 +647,6 @@ namespace build2
     }
   }
 
-
-
   // Extract the project name from bootstrap.build.
   //
   static project_name
@@ -673,10 +672,14 @@ namespace build2
           altn = s.root_extra->altn;
         else
           assert (*altn == s.root_extra->altn);
-      }
 
-      if (lookup l = s.vars[ctx.var_project])
-        return cast<project_name> (l);
+        if (s.root_extra->project)
+        {
+          return (*s.root_extra->project != nullptr
+                  ? **s.root_extra->project
+                  : empty_project_name);
+        }
+      }
 
       src_root = s.src_path_;
     }
@@ -856,6 +859,7 @@ namespace build2
     if (bf.empty ())
     {
       r = false;
+      rs.root_extra->project = nullptr; // Simple project.
     }
     // We assume that bootstrap out cannot load this file explicitly. It
     // feels wrong to allow this since that makes the whole bootstrap
@@ -864,6 +868,20 @@ namespace build2
     //
     else if (rs.buildfiles.insert (bf).second)
     {
+      // Extract and pre-cache the project name before loading
+      // bootstrap.build.
+      //
+      // @@ TODO: optimize by extracting both of them at once?
+      //
+      auto pp (extract_variable (ctx, bf, *ctx.var_project, 1));
+
+      if (!pp.second)
+        fail << "variable " << *ctx.var_project << " expected as a first "
+             << "line in " << bf;
+
+      const project_name pn (cast<project_name> (move (pp.first)));
+      rs.root_extra->project = &pn;
+
       // Deal with the empty amalgamation variable (which indicates that
       // amalgamating this project is disabled). We go through all this
       // trouble of extracting its value manually (and thus requiring its
@@ -882,6 +900,10 @@ namespace build2
         source (p, rs, rs, bf);
       }
 
+      // Update to point to the variable value.
+      //
+      rs.root_extra->project = &cast<project_name> (rs.vars[ctx.var_project]);
+
       // Detect and diagnose the case where the amalgamation variable is not
       // the second line.
       //
@@ -2001,8 +2023,7 @@ namespace build2
 
           // First check the amalgamation itself.
           //
-          if (r != &iroot &&
-              cast<project_name> (r->vars[ctx.var_project]) == proj)
+          if (r != &iroot && project (*r) == proj)
           {
             out_root = r->out_path ();
             break;
@@ -2137,7 +2158,7 @@ namespace build2
 
       // Now we know this project's name as well as all its subprojects.
       //
-      if (cast<project_name> (root->vars[ctx.var_project]) == proj)
+      if (project (*root) == proj)
         break;
 
       if (auto l = root->vars[ctx.var_subprojects])
diff --git a/libbuild2/operation.cxx b/libbuild2/operation.cxx
index 37baddd..6dd46c7 100644
--- a/libbuild2/operation.cxx
+++ b/libbuild2/operation.cxx
@@ -546,7 +546,7 @@ namespace build2
       // This could be a simple project that doesn't set project name.
       //
       cout
-        << "project: "      << cast_empty<project_name> (rs[ctx.var_project]) << endl
+        << "project: "      << project (rs) << endl
         << "version: "      << cast_empty<string> (rs[ctx.var_version]) << endl
         << "summary: "      << cast_empty<string> (rs[ctx.var_project_summary]) << endl
         << "url: "          << cast_empty<string> (rs[ctx.var_project_url]) << endl
diff --git a/libbuild2/scope.hxx b/libbuild2/scope.hxx
index 027fa46..bd1a70b 100644
--- a/libbuild2/scope.hxx
+++ b/libbuild2/scope.hxx
@@ -416,6 +416,14 @@ namespace build2
   public:
     struct root_extra_type
     {
+      // This project's name (var_project value). Absent means it is not yet
+      // determined. NULL means simple project. Empty means unnamed project.
+      //
+      // Note that it is set to point to a temporary value before loading
+      // bootstrap.build and to a permanent one (from the variable) after.
+      //
+      optional<const project_name*> project;
+
       // This project's amalgamation (var_amalgamation value). Absent means it
       // is not yet determined. NULL means amalgamation is disabled.
       //
@@ -562,6 +570,10 @@ namespace build2
 
   // Return the project name or empty if unnamed.
   //
+  // Note that this function and named_project() below expect the root scope
+  // to either be already bootstrapped or being src-bootstrapped (see
+  // bootstrap_src()).
+  //
   const project_name&
   project (const scope& root);
 
diff --git a/libbuild2/scope.ixx b/libbuild2/scope.ixx
index a3a417f..01d239b 100644
--- a/libbuild2/scope.ixx
+++ b/libbuild2/scope.ixx
@@ -162,8 +162,11 @@ namespace build2
   inline const project_name&
   project (const scope& rs)
   {
-    auto l (rs[rs.ctx.var_project]);
-    return l ? cast<project_name> (l) : empty_project_name;
+    assert (rs.root_extra != nullptr && rs.root_extra->project);
+
+    return *rs.root_extra->project != nullptr
+      ? **rs.root_extra->project
+      : empty_project_name;
   }
 
   inline const project_name&
diff --git a/libbuild2/version/init.cxx b/libbuild2/version/init.cxx
index 7c5d589..681b6a4 100644
--- a/libbuild2/version/init.cxx
+++ b/libbuild2/version/init.cxx
@@ -68,19 +68,19 @@ namespace build2
           {
             if (nv.name == "name")
             {
-              auto* pn (cast_null<project_name> (rs.vars[ctx.var_project]));
+              const project_name& pn (project (rs));
 
-              if (pn == nullptr)
+              if (pn.empty ())
                 fail (l) << "version module loaded in unnamed project";
 
-              if (nv.value != pn->string ())
+              if (nv.value != pn.string ())
               {
                 path bf (rs.src_path () / rs.root_extra->bootstrap_file);
                 location ml (f, nv.value_line, nv.value_column);
                 location bl (bf);
 
                 fail (ml) << "package name " << nv.value << " does not match "
-                          << "build system project name " << *pn <<
+                          << "build system project name " << pn <<
                   info (bl) << "build system project name specified here";
               }
             }
@@ -273,7 +273,7 @@ namespace build2
       // Create the module instance.
       //
       extra.set_module (
-        new module (cast<project_name> (rs.vars[ctx.var_project]),
+        new module (project (rs),
                     move (v),
                     committed,
                     rewritten,
@@ -298,8 +298,6 @@ namespace build2
       if (!first)
         fail (l) << "multiple version module initializations";
 
-      context& ctx (rs.ctx);
-
       // Load in.base (in.* variables, in{} target type).
       //
       load_module (rs, rs, "in.base", l);
@@ -324,7 +322,9 @@ namespace build2
 
         if (!val)
         {
-          string p (cast<project_name> (rs.vars[ctx.var_project]).string ());
+          // We've already verified in boot() it is named.
+          //
+          string p (project (rs).string ());
           p += '-';
           p += v.string ();
           val = move (p);