Add load_default_options() function template overload that accepts tracing function

4 files changed, 52 insertions, 24 deletions

diff --git a/libbutl/default-options.ixx b/libbutl/default-options.ixx
new file mode 100644
index 0000000..e1a3dcf
--- /dev/null
+++ b/libbutl/default-options.ixx
@@ -0,0 +1,16 @@
+// file      : libbutl/default-options.ixx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
+{
+  template <typename O>
+  inline O
+  merge_default_options (const default_options<O>& def_ops, const O& cmd_ops)
+  {
+    return merge_default_options (
+      def_ops,
+      cmd_ops,
+      [] (const default_options_entry<O>&, const O&) {});
+  }
+}
diff --git a/libbutl/default-options.mxx b/libbutl/default-options.mxx
index 01d32c1..d7aa70b 100644
--- a/libbutl/default-options.mxx
+++ b/libbutl/default-options.mxx
@@ -7,7 +7,7 @@
 #endif
 
 #ifndef __cpp_lib_modules_ts
-#include <utility> // move()
+#include <utility> // move(), forward()
 #endif
 
 // Other includes.
@@ -58,6 +58,11 @@ LIBBUTL_MODEXPORT namespace butl
   // Search for and load (using scanner S and parsing in the U::fail mode for
   // both options and arguments) the specified list of options files in the
   // specified directories returning a vector of option class instances (O).
+  // Pass each default options file path to the specified function prior to
+  // load (can be used for tracing, etc). The function signature is:
+  //
+  // void (const path&, bool remote)
+  //
   // Throw std::system_error on the underlying OS error and pass through
   // exceptions thrown by the options scanner/parser.
   //
@@ -80,11 +85,12 @@ LIBBUTL_MODEXPORT namespace butl
   // sufficient ground to definititevly conclude that the file is not remote;
   // to be sure we would need to query the VCS or some such).
   //
-  template <typename O, typename S, typename U>
+  template <typename O, typename S, typename U, typename F>
   default_options<O>
   load_default_options (const optional<dir_path>& sys_dir,
                         const optional<dir_path>& home_dir,
-                        const default_options_files&);
+                        const default_options_files&,
+                        F&&);
 
   // Merge the default options and the command line options.
   //
@@ -112,4 +118,5 @@ LIBBUTL_MODEXPORT namespace butl
   merge_default_options (const default_options<O>&, const O&, F&&);
 }
 
+#include <libbutl/default-options.ixx>
 #include <libbutl/default-options.txx>
diff --git a/libbutl/default-options.txx b/libbutl/default-options.txx
index 42dd585..2ed12e4 100644
--- a/libbutl/default-options.txx
+++ b/libbutl/default-options.txx
@@ -17,14 +17,15 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
   // in both the directory itself and its local/ subdirectory are considered
   // remote (see load_default_options() for details).
   //
-  template <typename O, typename S, typename U>
+  template <typename O, typename S, typename U, typename F>
   void
   load_default_options_files (const dir_path& d,
                               bool remote,
                               const small_vector<path, 2>& fs,
+                              F&& fn,
                               default_options<O>& r)
   {
-    auto load = [&fs, &r] (const dir_path& d, bool remote)
+    auto load = [&fs, &fn, &r] (const dir_path& d, bool remote)
     {
       using namespace std;
 
@@ -34,6 +35,8 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
 
         if (file_exists (p)) // Follows symlinks.
         {
+          fn (p, remote);
+
           S s (p.string ());
 
           // @@ Note that the potentially thrown exceptions (unknown option,
@@ -63,11 +66,12 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
   // to the resulting list. Return true if the directory is "remote" (i.e.,
   // belongs to a VCS repository).
   //
-  template <typename O, typename S, typename U>
+  template <typename O, typename S, typename U, typename F>
   bool
   load_default_options_files (const dir_path& start_dir,
                               const optional<dir_path>& home_dir,
                               const small_vector<path, 2>& fs,
+                              F&& fn,
                               default_options<O>& r)
   {
     if (start_dir.root () || (home_dir && start_dir == *home_dir))
@@ -76,22 +80,28 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
     bool remote (load_default_options_files<O, S, U> (start_dir.directory (),
                                                      home_dir,
                                                      fs,
+                                                     std::forward<F> (fn),
                                                      r) ||
                  git_repository (start_dir));
 
     dir_path d (start_dir / dir_path (".build2"));
 
     if (dir_exists (d))
-      load_default_options_files<O, S, U> (d, remote, fs, r);
+      load_default_options_files<O, S, U> (d,
+                                           remote,
+                                           fs,
+                                           std::forward<F> (fn),
+                                           r);
 
     return remote;
   }
 
-  template <typename O, typename S, typename U>
+  template <typename O, typename S, typename U, typename F>
   default_options<O>
   load_default_options (const optional<dir_path>& sys_dir,
                         const optional<dir_path>& home_dir,
-                        const default_options_files& ofs)
+                        const default_options_files& ofs,
+                        F&& fn)
   {
     default_options<O> r;
 
@@ -103,6 +113,7 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
         load_default_options_files<O, S, U> (*sys_dir,
                                              false /* remote */,
                                              ofs.files,
+                                             std::forward<F> (fn),
                                              r);
     }
 
@@ -116,6 +127,7 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
         load_default_options_files<O, S, U> (d,
                                              false /* remote */,
                                              ofs.files,
+                                             std::forward<F> (fn),
                                              r);
     }
 
@@ -126,6 +138,7 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
       load_default_options_files<O, S, U> (*ofs.start_dir,
                                            home_dir,
                                            ofs.files,
+                                           std::forward<F> (fn),
                                            r);
     }
 
@@ -136,7 +149,7 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
   O
   merge_default_options (const default_options<O>& def_ops,
                          const O& cmd_ops,
-                         F&& f)
+                         F&& fn)
   {
     // Optimize for the common case.
     //
@@ -146,21 +159,11 @@ LIBBUTL_MODEXPORT namespace butl //@@ MOD Clang needs this for some reason.
     O r;
     for (const default_options_entry<O>& e: def_ops)
     {
-      f (e, cmd_ops);
+      fn (e, cmd_ops);
       r.merge (e.options);
     }
 
     r.merge (cmd_ops);
     return r;
   }
-
-  template <typename O>
-  inline O
-  merge_default_options (const default_options<O>& def_ops, const O& cmd_ops)
-  {
-    return merge_default_options (
-      def_ops,
-      cmd_ops,
-      [] (const default_options_entry<O>&, const O&) {});
-  }
 }
diff --git a/tests/default-options/driver.cxx b/tests/default-options/driver.cxx
index a2ed43d..535df31 100644
--- a/tests/default-options/driver.cxx
+++ b/tests/default-options/driver.cxx
@@ -150,9 +150,11 @@ main (int argc, const char* argv[])
   // Load and print the default options.
   //
   default_options<options> def_ops (
-    load_default_options<options, scanner, unknow_mode> (sys_dir,
-                                                         home_dir,
-                                                         fs));
+    load_default_options<options, scanner, unknow_mode> (
+      sys_dir,
+      home_dir,
+      fs,
+      [] (const path&, bool) {}));
 
   if (print_entries)
   {