From da89007801070651f592575f73dd4130dc324998 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 14 Feb 2022 11:58:58 +0200
Subject: Implement package skeleton loading and enable and reflect clauses
 evaluation

---
 bpkg/package-skeleton.hxx | 96 ++++++++++++++++-------------------------------
 1 file changed, 33 insertions(+), 63 deletions(-)

(limited to 'bpkg/package-skeleton.hxx')

diff --git a/bpkg/package-skeleton.hxx b/bpkg/package-skeleton.hxx
index 1a56bfb..c4c59cc 100644
--- a/bpkg/package-skeleton.hxx
+++ b/bpkg/package-skeleton.hxx
@@ -19,14 +19,14 @@ namespace bpkg
   class package_skeleton
   {
   public:
-    // If the package is external and will not be disfigured, then the
-    // existing package source root directory needs to be specified. In this
-    // case this source directory and the automatically deduced potentially
-    // non-existent out root directory will be used for build2 state loading
-    // instead of the newly created skeleton directory. This, in particular,
-    // makes sure we take into account the existing configuration variables
-    // while evaluating the dependency clauses (this logic is "parallel" to
-    // the configuration preservation in pkg-build.cxx).
+    // If the package is external, then the existing package source root
+    // directory needs to be specified (as absolute and normalized). In this
+    // case, if output root is specified (as absolute and normalized; normally
+    // <config-dir>/<package-name>), then it's used as is. Otherwise, an empty
+    // skeleton directory is used as output root.
+    //
+    // If the package is not external, then none of the root directories
+    // should be specified.
     //
     // Note that the database and available_package are expected to outlive
     // this object.
@@ -34,70 +34,38 @@ namespace bpkg
     // Note also that this creates an "unloaded" skeleton and is therefore
     // cheap.
     //
-    // @@ Note that storing the list of configuration variables by reference
-    //    complicates its use in pkg-build, where both the configuration and
-    //    the optional skeleton are parts of the same copyable/moveable
-    //    build_package object. We could probably move the configuration into
-    //    the skeleton if create it, complicating an access to the
-    //    configuration for the users (if the skeleton is present then get
-    //    configuration from it, etc). Let's however keep it simple for now
-    //    and just copy the configuration.
-    //
     package_skeleton (database&,
                       const available_package&,
-                      const strings& cvs,
-                      optional<dir_path> src_root);
+                      strings config_vars,
+                      optional<dir_path> src_root,
+                      optional<dir_path> out_root);
 
-    // Evaluate the enable clause.
+    // For the following evaluate_*() functions assume that the clause belongs
+    // to the specified (by index) depends value (used to print its location
+    // on failure for an external package).
     //
-    // @@ What can we pass as location? Maybe somehow point to manifest in the
-    //    skeleton (will need to re-acquire the position somehow)?
+    // Evaluate the enable clause.
     //
     bool
-    evaluate_enable (const string&)
-    {
-      // @@ TMP
-      //
-      fail << "conditional dependency for package " << name () <<
-        info << "conditional dependencies are not yet supported";
-
-      load ();
-
-      // TODO
-
-      return true; // @@ TMP
-    }
+    evaluate_enable (const string&, size_t depends_index);
 
     // Evaluate the reflect clause.
     //
     void
-    evaluate_reflect (const string& r)
-    {
-      load ();
-
-      // TODO
-
-      // @@ DEP For now we assume that the reflection, if present, contains
-      //    a single configuration variable that assigns a literal value.
-      //
-      reflect_.push_back (r);
-
-      // Mark the build system state as needing reloading since some computed
-      // values in root.build may depend on the new configuration values.
-      //
-      dirty_ = true;
-    }
+    evaluate_reflect (const string&, size_t depends_index);
 
     // Return the accumulated reflect values.
     //
+    // Note that the result is merged with config_vars and you should be used
+    // instead rather than in addition to config_vars.
+    //
+    // Note also that this should be the final call on this object.
+    //
     strings
-    collect_reflect ()
-    {
-      return reflect_;
-    }
+    collect_reflect () &&;
 
     const package_name&
-    name () const {return available_.get ().id.name;}
+    name () const {return available_->id.name;}
 
     // Implementation details.
     //
@@ -116,24 +84,26 @@ namespace bpkg
     //
     // Call this function before evaluating every clause.
     //
-    void
+    build2::scope&
     load ();
 
   private:
     // NOTE: remember to update move/copy constructors!
     //
-    reference_wrapper<database> db_;
-    reference_wrapper<const available_package> available_;
+    database* db_;
+    const available_package* available_;
     strings config_vars_;
 
-    dir_path src_root_;
+    dir_path src_root_; // Must be absolute and normalized.
     dir_path out_root_; // If empty, the same as src_root_.
 
-    unique_ptr<build2::context> ctx_;
     bool created_ = false;
-    bool dirty_ = false;
+    unique_ptr<build2::context> ctx_;
+    build2::scope* rs_ = nullptr;
 
-    strings reflect_;
+    strings reflect_names_; // Reflect configuration variable names.
+    strings reflect_vars_;  // Reflect configuration variable overrides.
+    string  reflect_frag_;  // Reflect configuration variable fragment.
   };
 }
 
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