Add abstract c_inc{} and cxx_inc{} target types

These abstract base target types are meant for deriving additional target
types (for example, Qt moc{}) that can be #include'd in C and C++ translation
units, respectively. In particular, only such targets will be considered to
reverse-lookup extensions to target types (see dyndep_rule::map_extension()
for background).

2 files changed, 32 insertions, 0 deletions

diff --git a/libbuild2/cc/target.cxx b/libbuild2/cc/target.cxx
index 6c5d7c8..6a518dd 100644
--- a/libbuild2/cc/target.cxx
+++ b/libbuild2/cc/target.cxx
@@ -80,6 +80,19 @@ namespace build2
       target_type::flag::none
     };
 
+    const target_type c_inc::static_type
+    {
+      "c_inc",
+      &cc::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      target_type::flag::none
+    };
+
     extern const char pc_ext[] = "pc"; // VC14 rejects constexpr.
     const target_type pc::static_type
     {
diff --git a/libbuild2/cc/target.hxx b/libbuild2/cc/target.hxx
index a078422..01f2d6e 100644
--- a/libbuild2/cc/target.hxx
+++ b/libbuild2/cc/target.hxx
@@ -100,6 +100,25 @@ namespace build2
       static const target_type static_type;
     };
 
+    // This is an abstract base target for deriving additional targets that
+    // can be #include'd in C translation units (the same rationale for having
+    // it here as for c{} above). In particular, only such targets will be
+    // considered to reverse-lookup extensions to target types (see
+    // dyndep_rule::map_extension() for background).
+    //
+    class LIBBUILD2_CC_SYMEXPORT c_inc: public cc
+    {
+    public:
+      c_inc (context& c, dir_path d, dir_path o, string n)
+        : cc (c, move (d), move (o), move (n))
+      {
+        dynamic_type = &static_type;
+      }
+
+    public:
+      static const target_type static_type;
+    };
+
     // pkg-config file targets.
     //
     class LIBBUILD2_CC_SYMEXPORT pc: public file // .pc (common)