Move cli module to libbuild2-cli library

This is a temporary measure (until we unboundle this module) needed for
in-process configure support in bpkg.

1 files changed, 287 insertions, 0 deletions

diff --git a/libbuild2/cli/init.cxx b/libbuild2/cli/init.cxx
new file mode 100644
index 0000000..581fdaf
--- /dev/null
+++ b/libbuild2/cli/init.cxx
@@ -0,0 +1,287 @@
+// file      : libbuild2/cli/init.cxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#include <libbuild2/cli/init.hxx>
+
+#include <libbuild2/file.hxx>
+#include <libbuild2/scope.hxx>
+#include <libbuild2/target.hxx>
+#include <libbuild2/variable.hxx>
+#include <libbuild2/diagnostics.hxx>
+
+#include <libbuild2/config/utility.hxx>
+
+#include <libbuild2/cxx/target.hxx>
+
+#include <libbuild2/cli/rule.hxx>
+#include <libbuild2/cli/module.hxx>
+#include <libbuild2/cli/target.hxx>
+
+namespace build2
+{
+  namespace cli
+  {
+    // Remaining issues/semantics change:
+    //
+    // @@ Unconfigured caching.
+    //
+    // @@ Default-found cli used to result in config.cli=cli and now it's just
+    //    omitted (and default-not-found -- in config.cli.configured=false).
+    //
+    //    - Writing any default will take precedence over config.import.cli.
+    //      In fact, this duality is a bigger problem: if we have a config
+    //      that uses config.cli there is no way to reconfigure it to use
+    //      config.import.cli.
+    //
+    //    - We could have saved it commented.
+    //
+    //    - We could do this at the module level only since we also have
+    //      config.cli.options?
+    //
+    //    - Note that in the CLI compiler itself we now rely on default cli
+    //      being NULL/undefined. So if faving, should probably be commented
+    //      out. BUT: it will still be defined, so will need to be defined
+    //      NULL. Note also that long term the CLI compiler will not use the
+    //      module relying on an ad hoc recipe instead.
+    //
+    //    ! Maybe reserving NULL (instead of making it the same as NULL) for
+    //      this "configured to default" state and saving commented is not a
+    //      bad idea. Feels right to have some marker in config.build that
+    //      things are in effect. And I believe if config.import.cli is
+    //      specified, it will just be dropped.
+
+    bool
+    guess_init (scope& rs,
+                scope& bs,
+                const location& loc,
+                bool,
+                bool opt,
+                module_init_extra& extra)
+    {
+      tracer trace ("cli::guess_init");
+      l5 ([&]{trace << "for " << rs;});
+
+      // We only support root loading (which means there can only be one).
+      //
+      if (rs != bs)
+        fail (loc) << "cli.guess module must be loaded in project root";
+
+      // Adjust module config.build save priority (code generator).
+      //
+      config::save_module (rs, "cli", 150);
+
+      // Enter metadata variables.
+      //
+      // They are all qualified so go straight for the public variable pool.
+      //
+      auto& vp (rs.var_pool (true /* public */));
+
+      auto& v_ver (vp.insert<string> ("cli.version"));
+      auto& v_sum (vp.insert<string> ("cli.checksum"));
+
+      // Import the CLI compiler target.
+      //
+      // Note that the special config.cli=false value (recognized by the
+      // import machinery) is treated as an explicit request to leave the
+      // module unconfigured.
+      //
+      bool new_cfg (false);
+      import_result<exe> ir (
+        import_direct<exe> (
+          new_cfg,
+          rs,
+          name ("cli", dir_path (), "exe", "cli"), // cli%exe{cli}
+          true      /* phase2 */,
+          opt,
+          true      /* metadata */,
+          loc,
+          "module load"));
+
+      const exe* tgt (ir.target);
+
+      // Extract metadata.
+      //
+      auto* ver (tgt != nullptr ? &cast<string> (tgt->vars[v_ver]) : nullptr);
+      auto* sum (tgt != nullptr ? &cast<string> (tgt->vars[v_sum]) : nullptr);
+
+      // Print the report.
+      //
+      // If this is a configuration with new values, then print the report
+      // at verbosity level 2 and up (-v).
+      //
+      if (verb >= (new_cfg ? 2 : 3))
+      {
+        diag_record dr (text);
+        dr << "cli " << project (rs) << '@' << rs << '\n';
+
+        if (tgt != nullptr)
+          dr << "  cli        " << ir << '\n'
+             << "  version    " << *ver << '\n'
+             << "  checksum   " << *sum;
+        else
+          dr << "  cli        " << "not found, leaving unconfigured";
+      }
+
+      if (tgt == nullptr)
+        return false;
+
+      // The cli variable (untyped) is an imported compiler target name.
+      //
+      rs.assign ("cli") = move (ir.name);
+      rs.assign (v_sum) = *sum;
+      rs.assign (v_ver) = *ver;
+
+      {
+        standard_version v (*ver);
+
+        rs.assign<uint64_t> ("cli.version.number") = v.version;
+        rs.assign<uint64_t> ("cli.version.major") = v.major ();
+        rs.assign<uint64_t> ("cli.version.minor") = v.minor ();
+        rs.assign<uint64_t> ("cli.version.patch") = v.patch ();
+      }
+
+      // Cache some values in the module for easier access in the rule.
+      //
+      extra.set_module (new module (data {*tgt, *sum}));
+
+      return true;
+    }
+
+    bool
+    config_init (scope& rs,
+                 scope& bs,
+                 const location& loc,
+                 bool,
+                 bool opt,
+                 module_init_extra& extra)
+    {
+      tracer trace ("cli::config_init");
+      l5 ([&]{trace << "for " << rs;});
+
+      // We only support root loading (which means there can only be one).
+      //
+      if (rs != bs)
+        fail (loc) << "cli.config module must be loaded in project root";
+
+      // Load cli.guess and share its module instance as ours.
+      //
+      if (optional<shared_ptr<build2::module>> r = load_module (
+            rs, rs, "cli.guess", loc, opt, extra.hints))
+      {
+        extra.module = *r;
+      }
+      else
+      {
+        // This can happen if someone already optionally loaded cli.guess
+        // and it has failed to configure.
+        //
+        if (!opt)
+          fail (loc) << "cli could not be configured" <<
+            info << "re-run with -V for more information";
+
+        return false;
+      }
+
+      // Configuration.
+      //
+      using config::append_config;
+
+      // config.cli.options
+      //
+      // Note that we merge it into the corresponding cli.* variable.
+      //
+      append_config<strings> (rs, rs, "cli.options", nullptr);
+
+      return true;
+    }
+
+    bool
+    init (scope& rs,
+          scope& bs,
+          const location& loc,
+          bool,
+          bool opt,
+          module_init_extra& extra)
+    {
+      tracer trace ("cli::init");
+      l5 ([&]{trace << "for " << rs;});
+
+      // We only support root loading (which means there can only be one).
+      //
+      if (rs != bs)
+        fail (loc) << "cli module must be loaded in project root";
+
+      // Make sure the cxx module has been loaded since we need its targets
+      // types (?xx{}). Note that we don't try to load it ourselves because of
+      // the non-trivial variable merging semantics. So it is better to let
+      // the user load cxx explicitly. @@ Not sure the reason still holds
+      // though it might still make sense to expect the user to load cxx.
+      //
+      if (!cast_false<bool> (rs["cxx.loaded"]))
+        fail (loc) << "cxx module must be loaded before cli";
+
+      // Load cli.config and get its module instance.
+      //
+      if (optional<shared_ptr<build2::module>> r = load_module (
+            rs, rs, "cli.config", loc, opt, extra.hints))
+      {
+        extra.module = *r;
+      }
+      else
+      {
+        // This can happen if someone already optionally loaded cli.config
+        // and it has failed to configure.
+        //
+        if (!opt)
+          fail (loc) << "cli could not be configured" <<
+            info << "re-run with -V for more information";
+
+        return false;
+      }
+
+      auto& m (extra.module_as<module> ());
+
+      // Register target types.
+      //
+      rs.insert_target_type<cli> ();
+      rs.insert_target_type<cli_cxx> ();
+
+      // Register our rules.
+      //
+      // Other rules (e.g., cc::compile) may need to have the group members
+      // resolved/linked up. Looks like a general pattern: groups should
+      // resolve on *(update).
+      {
+        auto reg = [&rs, &m] (meta_operation_id mid, operation_id oid)
+        {
+          rs.insert_rule<cli_cxx>  (mid, oid, "cli.compile", m);
+          rs.insert_rule<cxx::hxx> (mid, oid, "cli.compile", m);
+          rs.insert_rule<cxx::cxx> (mid, oid, "cli.compile", m);
+          rs.insert_rule<cxx::ixx> (mid, oid, "cli.compile", m);
+        };
+
+        reg (0 /* wildcard */, update_id);
+        reg (perform_id,       clean_id);
+      }
+
+      return true;
+    }
+
+    static const module_functions mod_functions[] =
+    {
+      // NOTE: don't forget to also update the documentation in init.hxx if
+      //       changing anything here.
+
+      {"cli.guess",  nullptr, guess_init},
+      {"cli.config", nullptr, config_init},
+      {"cli",        nullptr, init},
+      {nullptr,      nullptr, nullptr}
+    };
+
+    const module_functions*
+    build2_cli_load ()
+    {
+      return mod_functions;
+    }
+  }
+}