Add support for default options files

8 files changed, 312 insertions, 8 deletions

diff --git a/build2/b-options.cxx b/build2/b-options.cxx
index 4c8e63b..9ad7429 100644
--- a/build2/b-options.cxx
+++ b/build2/b-options.cxx
@@ -476,6 +476,12 @@ namespace build2
 
         xs = true;
       }
+
+      static void
+      merge (X& b, const X& a)
+      {
+        b = a;
+      }
     };
 
     template <>
@@ -487,6 +493,12 @@ namespace build2
         s.next ();
         x = true;
       }
+
+      static void
+      merge (bool& b, const bool&)
+      {
+        b = true;
+      }
     };
 
     template <>
@@ -504,6 +516,12 @@ namespace build2
 
         xs = true;
       }
+
+      static void
+      merge (std::string& b, const std::string& a)
+      {
+        b = a;
+      }
     };
 
     template <typename X>
@@ -518,6 +536,12 @@ namespace build2
         c.push_back (x);
         xs = true;
       }
+
+      static void
+      merge (std::vector<X>& b, const std::vector<X>& a)
+      {
+        b.insert (b.end (), a.begin (), a.end ());
+      }
     };
 
     template <typename X>
@@ -532,6 +556,12 @@ namespace build2
         c.insert (x);
         xs = true;
       }
+
+      static void
+      merge (std::set<X>& b, const std::set<X>& a)
+      {
+        b.insert (a.begin (), a.end ());
+      }
     };
 
     template <typename K, typename V>
@@ -580,6 +610,15 @@ namespace build2
 
         xs = true;
       }
+
+      static void
+      merge (std::map<K, V>& b, const std::map<K, V>& a)
+      {
+        for (typename std::map<K, V>::const_iterator i (a.begin ()); 
+             i != a.end (); 
+             ++i)
+          b[i->first] = i->second;
+      }
     };
 
     template <typename X, typename T, T X::*M>
@@ -644,6 +683,7 @@ namespace build2
     pager_specified_ (false),
     pager_option_ (),
     pager_option_specified_ (false),
+    no_default_options_ (),
     help_ (),
     version_ ()
   {
@@ -712,6 +752,191 @@ namespace build2
     return r;
   }
 
+  void options::
+  merge (const options& a)
+  {
+    CLI_POTENTIALLY_UNUSED (a);
+
+    if (a.v_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->v_, a.v_);
+    }
+
+    if (a.V_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->V_, a.V_);
+    }
+
+    if (a.quiet_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->quiet_, a.quiet_);
+    }
+
+    if (a.verbose_specified_)
+    {
+      ::build2::cl::parser< uint16_t>::merge (
+        this->verbose_, a.verbose_);
+      this->verbose_specified_ = true;
+    }
+
+    if (a.stat_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->stat_, a.stat_);
+    }
+
+    if (a.dump_specified_)
+    {
+      ::build2::cl::parser< std::set<string>>::merge (
+        this->dump_, a.dump_);
+      this->dump_specified_ = true;
+    }
+
+    if (a.progress_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->progress_, a.progress_);
+    }
+
+    if (a.no_progress_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->no_progress_, a.no_progress_);
+    }
+
+    if (a.jobs_specified_)
+    {
+      ::build2::cl::parser< size_t>::merge (
+        this->jobs_, a.jobs_);
+      this->jobs_specified_ = true;
+    }
+
+    if (a.max_jobs_specified_)
+    {
+      ::build2::cl::parser< size_t>::merge (
+        this->max_jobs_, a.max_jobs_);
+      this->max_jobs_specified_ = true;
+    }
+
+    if (a.queue_depth_specified_)
+    {
+      ::build2::cl::parser< size_t>::merge (
+        this->queue_depth_, a.queue_depth_);
+      this->queue_depth_specified_ = true;
+    }
+
+    if (a.max_stack_specified_)
+    {
+      ::build2::cl::parser< size_t>::merge (
+        this->max_stack_, a.max_stack_);
+      this->max_stack_specified_ = true;
+    }
+
+    if (a.serial_stop_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->serial_stop_, a.serial_stop_);
+    }
+
+    if (a.dry_run_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->dry_run_, a.dry_run_);
+    }
+
+    if (a.match_only_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->match_only_, a.match_only_);
+    }
+
+    if (a.structured_result_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->structured_result_, a.structured_result_);
+    }
+
+    if (a.mtime_check_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->mtime_check_, a.mtime_check_);
+    }
+
+    if (a.no_mtime_check_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->no_mtime_check_, a.no_mtime_check_);
+    }
+
+    if (a.no_column_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->no_column_, a.no_column_);
+    }
+
+    if (a.no_line_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->no_line_, a.no_line_);
+    }
+
+    if (a.buildfile_specified_)
+    {
+      ::build2::cl::parser< path>::merge (
+        this->buildfile_, a.buildfile_);
+      this->buildfile_specified_ = true;
+    }
+
+    if (a.config_guess_specified_)
+    {
+      ::build2::cl::parser< path>::merge (
+        this->config_guess_, a.config_guess_);
+      this->config_guess_specified_ = true;
+    }
+
+    if (a.config_sub_specified_)
+    {
+      ::build2::cl::parser< path>::merge (
+        this->config_sub_, a.config_sub_);
+      this->config_sub_specified_ = true;
+    }
+
+    if (a.pager_specified_)
+    {
+      ::build2::cl::parser< string>::merge (
+        this->pager_, a.pager_);
+      this->pager_specified_ = true;
+    }
+
+    if (a.pager_option_specified_)
+    {
+      ::build2::cl::parser< strings>::merge (
+        this->pager_option_, a.pager_option_);
+      this->pager_option_specified_ = true;
+    }
+
+    if (a.no_default_options_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->no_default_options_, a.no_default_options_);
+    }
+
+    if (a.help_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->help_, a.help_);
+    }
+
+    if (a.version_)
+    {
+      ::build2::cl::parser< bool>::merge (
+        this->version_, a.version_);
+    }
+  }
+
   ::build2::cl::usage_para options::
   print_usage (::std::ostream& os, ::build2::cl::usage_para p)
   {
@@ -899,6 +1124,9 @@ namespace build2
        << "                     this option to specify multiple pager options." << ::std::endl;
 
     os << std::endl
+       << "\033[1m--no-default-options\033[0m Don't load default options files." << ::std::endl;
+
+    os << std::endl
        << "\033[1m--help\033[0m               Print usage information and exit." << ::std::endl;
 
     os << std::endl
@@ -995,6 +1223,8 @@ namespace build2
       _cli_options_map_["--pager-option"] = 
       &::build2::cl::thunk< options, strings, &options::pager_option_,
         &options::pager_option_specified_ >;
+      _cli_options_map_["--no-default-options"] = 
+      &::build2::cl::thunk< options, bool, &options::no_default_options_ >;
       _cli_options_map_["--help"] = 
       &::build2::cl::thunk< options, bool, &options::help_ >;
       _cli_options_map_["--version"] = 
diff --git a/build2/b-options.hxx b/build2/b-options.hxx
index 3e10901..297e6a4 100644
--- a/build2/b-options.hxx
+++ b/build2/b-options.hxx
@@ -422,6 +422,12 @@ namespace build2
            ::build2::cl::unknown_mode option = ::build2::cl::unknown_mode::fail,
            ::build2::cl::unknown_mode argument = ::build2::cl::unknown_mode::stop);
 
+    // Merge options from the specified instance appending/overriding
+    // them as if they appeared after options in this instance.
+    //
+    void
+    merge (const options&);
+
     // Option accessors.
     //
     const bool&
@@ -533,6 +539,9 @@ namespace build2
     pager_option_specified () const;
 
     const bool&
+    no_default_options () const;
+
+    const bool&
     help () const;
 
     const bool&
@@ -593,6 +602,7 @@ namespace build2
     bool pager_specified_;
     strings pager_option_;
     bool pager_option_specified_;
+    bool no_default_options_;
     bool help_;
     bool version_;
   };
diff --git a/build2/b-options.ixx b/build2/b-options.ixx
index a8dd01c..ab5af3f 100644
--- a/build2/b-options.ixx
+++ b/build2/b-options.ixx
@@ -477,6 +477,12 @@ namespace build2
   }
 
   inline const bool& options::
+  no_default_options () const
+  {
+    return this->no_default_options_;
+  }
+
+  inline const bool& options::
   help () const
   {
     return this->help_;
diff --git a/build2/b.cli b/build2/b.cli
index 4ab397b..f0ddb93 100644
--- a/build2/b.cli
+++ b/build2/b.cli
@@ -622,6 +622,11 @@ namespace build2
        specify multiple pager options."
     }
 
+    bool --no-default-options
+    {
+      "Don't load default options files."
+    }
+
     bool --help {"Print usage information and exit."}
     bool --version {"Print version and exit."}
   };
diff --git a/build2/b.cxx b/build2/b.cxx
index 8965d64..15844dc 100644
--- a/build2/b.cxx
+++ b/build2/b.cxx
@@ -19,8 +19,9 @@
 #include <exception> // terminate(), set_terminate(), terminate_handler
 
 #include <libbutl/pager.mxx>
-#include <libbutl/fdstream.mxx>  // stderr_fd(), fdterm()
-#include <libbutl/backtrace.mxx> // backtrace()
+#include <libbutl/fdstream.mxx>        // stderr_fd(), fdterm()
+#include <libbutl/backtrace.mxx>       // backtrace()
+#include <libbutl/default-options.mxx>
 
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
@@ -225,6 +226,18 @@ main (int argc, char* argv[])
   //
   try
   {
+    // Note that the diagnostics verbosity level can only be calculated after
+    // default options are loaded and merged (see below). Thus, to trace the
+    // default options files search, we refer to the verbosity level specified
+    // on the command line.
+    //
+    auto verbosity = [] ()
+    {
+      return ops.verbose_specified ()
+             ? ops.verbose ()
+             : ops.V () ? 3 : ops.v () ? 2 : ops.quiet () ? 0 : 1;
+    };
+
     // We want to be able to specify options, vars, and buildspecs in any
     // order (it is really handy to just add -v at the end of the command
     // line).
@@ -349,6 +362,36 @@ main (int argc, char* argv[])
           args += ')';
       }
 
+      // Handle default options files.
+      //
+      if (!ops.no_default_options ()) // Command line option.
+      try
+      {
+        ops = merge_default_options (
+          load_default_options<options,
+                               cl::argv_file_scanner,
+                               cl::unknown_mode> (
+            nullopt /* sys_dir */,
+            path::home_directory (), // The home variable is not assigned yet.
+            default_options_files {{path ("b.options")},
+                                   nullopt /* start_dir */},
+            [&trace, &verbosity] (const path& f, bool remote)
+            {
+              if (verbosity () >= 3)
+                trace << "loading " << (remote ? "remote " : "local ") << f;
+            }),
+          ops);
+      }
+      catch (const pair<path, system_error>& e)
+      {
+        fail << "unable to load default options files: " << e.first << ": "
+             << e.second;
+      }
+      catch (const system_error& e)
+      {
+        fail << "unable to obtain home directory: " << e;
+      }
+
       // Validate options.
       //
       if (ops.progress () && ops.no_progress ())
@@ -364,9 +407,7 @@ main (int argc, char* argv[])
 
     // Initialize the diagnostics state.
     //
-    init_diag ((ops.verbose_specified ()
-                ? ops.verbose ()
-                : ops.V () ? 3 : ops.v () ? 2 : ops.quiet () ? 0 : 1),
+    init_diag (verbosity (),
                (ops.progress ()    ? optional<bool> (true)  :
                 ops.no_progress () ? optional<bool> (false) : nullopt),
                ops.no_line (),
diff --git a/build2/buildfile b/build2/buildfile
index d3b937f..d8b045a 100644
--- a/build2/buildfile
+++ b/build2/buildfile
@@ -90,7 +90,7 @@ if $cli.configured
 --include-prefix build2 --guard-prefix BUILD2 \
 --cxx-prologue "#include <build2/types-parsers.hxx>" \
 --cli-namespace build2::cl --generate-file-scanner --keep-separator \
---generate-parse --generate-specifier
+--generate-parse --generate-merge --generate-specifier
 
   # Usage options.
   #
diff --git a/build2/types-parsers.hxx b/build2/types-parsers.hxx
index beea977..db55c05 100644
--- a/build2/types-parsers.hxx
+++ b/build2/types-parsers.hxx
@@ -24,6 +24,9 @@ namespace build2
     {
       static void
       parse (path&, bool&, scanner&);
+
+      static void
+      merge (path& b, const path& a) {b = a;}
     };
 
     template <>
@@ -31,6 +34,9 @@ namespace build2
     {
       static void
       parse (dir_path&, bool&, scanner&);
+
+      static void
+      merge (dir_path& b, const dir_path& a) {b = a;}
     };
   }
 }
diff --git a/libbuild2/utility.cxx b/libbuild2/utility.cxx
index 506e88e..79545cc 100644
--- a/libbuild2/utility.cxx
+++ b/libbuild2/utility.cxx
@@ -143,7 +143,6 @@ namespace build2
         else if (rb.sub (home))
           return "~/" + rb.leaf (home).representation ();
       }
-
 #endif
 
       return move (rb).representation ();
@@ -515,6 +514,13 @@ namespace build2
       fail << "invalid current working directory: " << e;
     }
 
-    home = dir_path::home_directory ();
+    try
+    {
+      home = dir_path::home_directory ();
+    }
+    catch (const system_error& e)
+    {
+      fail << "unable to obtain home directory: " << e;
+    }
   }
 }