Use prefix_map for scopes, establish root scope

11 files changed, 120 insertions, 14 deletions

diff --git a/build/b.cxx b/build/b.cxx
index 05dac4c..492fdea 100644
--- a/build/b.cxx
+++ b/build/b.cxx
@@ -152,6 +152,16 @@ main (int argc, char* argv[])
       trace << "src_root: " << src_root.string ();
     }
 
+    // Create root scope. For Win32 we use the empty path since there
+    // is no such "real" root path. On POSIX, however, this is a real
+    // path. See the comment in <build/path-map> for details.
+    //
+#ifdef _WIN32
+    root_scope = &scopes[path ()];
+#else
+    root_scope = &scopes[path ("/")];
+#endif
+
     // Parse buildfile.
     //
     path bf ("buildfile");
diff --git a/build/context b/build/context
index c177603..4f5b029 100644
--- a/build/context
+++ b/build/context
@@ -21,6 +21,9 @@ namespace build
   extern path src_base;
   extern path out_base;
 
+  class scope;
+  extern scope* root_scope;
+
   // Return the src/out directory corresponding to the given out/src. The
   // passed directory should be a sub-directory of out/src_root.
   //
diff --git a/build/context.cxx b/build/context.cxx
index 79753ec..a298d41 100644
--- a/build/context.cxx
+++ b/build/context.cxx
@@ -20,6 +20,8 @@ namespace build
   path src_base;
   path out_base;
 
+  scope* root_scope;
+
   path
   src_out (const path& o)
   {
diff --git a/build/parser.cxx b/build/parser.cxx
index 5102c60..9ebf8d3 100644
--- a/build/parser.cxx
+++ b/build/parser.cxx
@@ -158,8 +158,15 @@ namespace build
             if (dir)
             {
               scope& prev (*scope_);
-              path p (tns[0].name);
 
+              // On Win32 translate the root path to the special empty path.
+              // Search for root_scope for details.
+              //
+#ifdef _WIN32
+              path p (tns[0].name != "/" ? path (tns[0].name) : path ());
+#else
+              path p (tns[0].name);
+#endif
               if (p.relative ())
                 p = prev.path () / p;
 
@@ -197,9 +204,14 @@ namespace build
 
         // Dependency declaration.
         //
-        if (tt == type::name || tt == type::lcbrace || tt == type::newline)
+        if (tt == type::name    ||
+            tt == type::lcbrace ||
+            tt == type::newline ||
+            tt == type::eos)
         {
-          names_type pns (tt != type::newline ? names (t, tt) : names_type ());
+          names_type pns (tt != type::newline && tt != type::eos
+                          ? names (t, tt)
+                          : names_type ());
 
           // Prepare the prerequisite list.
           //
@@ -224,7 +236,7 @@ namespace build
                 n = move (pn.name); // NOTE: steal!
               else
               {
-                d /= path (pn.name, i);
+                d /= path (pn.name, i != 0 ? i : 1); // Special case: "/".
                 n.assign (pn.name, i + 1, string::npos);
               }
 
@@ -292,7 +304,7 @@ namespace build
                 n = move (tn.name); // NOTE: steal!
               else
               {
-                d /= path (tn.name, i);
+                d /= path (tn.name, i != 0 ? i : 1); // Special case: "/".
                 n.assign (tn.name, i + 1, string::npos);
               }
 
@@ -630,7 +642,10 @@ namespace build
   peek ()
   {
     if (!peeked_)
+    {
       peek_ = lexer_->next ();
+      peeked_ = true;
+    }
 
     return peek_.type ();
   }
diff --git a/build/path-map b/build/path-map
new file mode 100644
index 0000000..c422dde
--- /dev/null
+++ b/build/path-map
@@ -0,0 +1,77 @@
+// file      : build/path-map -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef BUILD_PATH_MAP
+#define BUILD_PATH_MAP
+
+#include <build/path>
+#include <build/prefix-map>
+
+namespace build
+{
+  // prefix_map for paths
+  //
+  // The paths should be normalized.
+  //
+  // Note that the path's representation of POSIX root ('/') is
+  // inconsistent in that we have a trailing delimiter at the end of
+  // the path (its "proper" representation would have been an empty
+  // string but that would have clashed with empty paths). To work
+  // around this snag, this implementation, during key comparison,
+  // detects '/' and treats it as empty. Note that the map will
+  // still store the key as you have first inserted it. So if you
+  // want a particular representation, pre-populate the map with
+  // it.
+  //
+  template <typename C>
+  struct compare_prefix<basic_path<C>>: compare_prefix<std::basic_string<C>>
+  {
+    typedef basic_path<C> K;
+
+    typedef C char_type;
+    typedef std::basic_string<C> string_type;
+    typedef compare_prefix<std::basic_string<C>> base;
+
+    explicit
+    compare_prefix (C d): base (d) {}
+
+    bool
+    operator() (const K& x, const K& y) const
+    {
+      const auto& xs (x.string ());
+      const auto& ys (y.string ());
+
+#ifdef _WIN32
+      return base::compare (xs.c_str (),
+                            xs.size (),
+                            ys.c_str (),
+                            ys.size ()) < 0;
+#else
+      return base::compare (xs.c_str (),
+                            x.root () ? 0 : xs.size (),
+                            ys.c_str (),
+                            y.root () ? 0 : ys.size ()) < 0;
+#endif
+    }
+
+    bool
+    prefix (const K& p, const K& k) const
+    {
+      const auto& ps (p.string ());
+      const auto& ks (k.string ());
+
+#ifdef _WIN32
+      return base::prefix (ps, ks);
+#else
+      return base::prefix (p.root () ? string_type () : ps,
+                           k.root () ? string_type () : ks);
+#endif
+    }
+  };
+
+  template <typename T>
+  using path_map = prefix_map<path, T, path::traits::directory_separator>;
+}
+
+#endif // BUILD_PATH_MAP
diff --git a/build/path.txx b/build/path.txx
index 881dc17..5fbabbd 100644
--- a/build/path.txx
+++ b/build/path.txx
@@ -58,7 +58,7 @@ namespace build
   basic_path<C>& basic_path<C>::
   operator/= (basic_path<C> const& r)
   {
-    if (r.absolute ())
+    if (r.absolute () && !path_.empty ()) // Allow ('' / '/foo').
       throw invalid_basic_path<C> (r.path_);
 
     if (path_.empty () || r.path_.empty ())
diff --git a/build/prefix-map b/build/prefix-map
index a385ca8..1b00337 100644
--- a/build/prefix-map
+++ b/build/prefix-map
@@ -44,6 +44,7 @@ namespace build
           p.c_str (), pn, k.c_str (), pn == k.size () ? pn : pn + 1) == 0;
     }
 
+  protected:
     int
     compare (const C* x, size_type xn,
              const C* y, size_type yn) const
diff --git a/build/prerequisite.cxx b/build/prerequisite.cxx
index debafe6..f2c72e5 100644
--- a/build/prerequisite.cxx
+++ b/build/prerequisite.cxx
@@ -30,7 +30,7 @@ namespace build
       {
         string s (diag_relative_work (p.scope.path ()));
 
-        if (!s.empty ())
+        if (!s.empty () && s.back () != path::traits::directory_separator)
           os << s << path::traits::directory_separator << ": ";
       }
 
@@ -40,7 +40,7 @@ namespace build
       {
         string s (diag_relative_work (p.dir));
 
-        if (!s.empty ())
+        if (!s.empty () && s.back () != path::traits::directory_separator)
           os << s << path::traits::directory_separator;
       }
 
diff --git a/build/scope b/build/scope
index 760fc03..58f7933 100644
--- a/build/scope
+++ b/build/scope
@@ -5,9 +5,8 @@
 #ifndef BUILD_SCOPE
 #define BUILD_SCOPE
 
-#include <map>
-
 #include <build/path>
+#include <build/path-map>
 #include <build/prerequisite>
 
 namespace build
@@ -23,7 +22,7 @@ namespace build
   private:
     friend class scope_map;
 
-    typedef std::map<path_type, scope>::const_iterator iterator;
+    typedef path_map<scope>::const_iterator iterator;
 
     scope () = default;
 
@@ -37,7 +36,7 @@ namespace build
     iterator i_;
   };
 
-  class scope_map: std::map<path, scope>
+  class scope_map: path_map<scope>
   {
   public:
     scope&
diff --git a/build/target.cxx b/build/target.cxx
index 235ceef..bb578c1 100644
--- a/build/target.cxx
+++ b/build/target.cxx
@@ -33,7 +33,7 @@ namespace build
       {
         os << s;
 
-        if (!t.name.empty ())
+        if (!t.name.empty () && s.back () != path::traits::directory_separator)
           os << path::traits::directory_separator;
       }
     }
diff --git a/build/utility b/build/utility
index 5523e8b..f429598 100644
--- a/build/utility
+++ b/build/utility
@@ -12,7 +12,6 @@
 #include <exception>
 #include <unordered_set>
 
-
 namespace build
 {
   struct compare_c_string