From 18e079b37794dc97b6c51045476bf43296b56dd3 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 22 Aug 2023 09:43:20 +0200
Subject: 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).
---
 libbuild2/c/init.cxx     |  3 ++-
 libbuild2/c/target.hxx   |  1 +
 libbuild2/cc/target.cxx  | 13 +++++++++++++
 libbuild2/cc/target.hxx  | 19 +++++++++++++++++++
 libbuild2/cxx/init.cxx   |  6 ++++--
 libbuild2/cxx/target.cxx | 13 +++++++++++++
 libbuild2/cxx/target.hxx | 20 +++++++++++++++++++-
 7 files changed, 71 insertions(+), 4 deletions(-)

diff --git a/libbuild2/c/init.cxx b/libbuild2/c/init.cxx
index c3d8174..1922a99 100644
--- a/libbuild2/c/init.cxx
+++ b/libbuild2/c/init.cxx
@@ -350,7 +350,7 @@ namespace build2
     };
 
     // Note that we include S{} here because .S files can include each other.
-    // (And maybe from inline assember instrcutions?)
+    // (And maybe from inline assembler instructions?)
     //
     static const target_type* const inc[] =
     {
@@ -358,6 +358,7 @@ namespace build2
       &c::static_type,
       &m::static_type,
       &S::static_type,
+      &c_inc::static_type,
       nullptr
     };
 
diff --git a/libbuild2/c/target.hxx b/libbuild2/c/target.hxx
index 39fcf89..c9955e3 100644
--- a/libbuild2/c/target.hxx
+++ b/libbuild2/c/target.hxx
@@ -17,6 +17,7 @@ namespace build2
     using cc::c;
     using cc::m;
     using cc::S;
+    using cc::c_inc;
   }
 }
 
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)
diff --git a/libbuild2/cxx/init.cxx b/libbuild2/cxx/init.cxx
index 3cf330f..d5476a6 100644
--- a/libbuild2/cxx/init.cxx
+++ b/libbuild2/cxx/init.cxx
@@ -806,8 +806,8 @@ namespace build2
     };
 
     // Note that we don't include S{} here because none of the files we
-    // compile can plausibly want to include .S. (Maybe in inline assember
-    // instrcutions?)
+    // compile can plausibly want to include .S. (Maybe in inline assembler
+    // instructions?)
     //
     static const target_type* const inc[] =
     {
@@ -820,6 +820,8 @@ namespace build2
       &c::static_type,
       &mm::static_type,
       &m::static_type,
+      &cxx_inc::static_type,
+      &cc::c_inc::static_type,
       nullptr
     };
 
diff --git a/libbuild2/cxx/target.cxx b/libbuild2/cxx/target.cxx
index 5ead620..37096c3 100644
--- a/libbuild2/cxx/target.cxx
+++ b/libbuild2/cxx/target.cxx
@@ -90,5 +90,18 @@ namespace build2
       &file_search,
       target_type::flag::none
     };
+
+    const target_type cxx_inc::static_type
+    {
+      "cxx_inc",
+      &cc::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      target_type::flag::none
+    };
   }
 }
diff --git a/libbuild2/cxx/target.hxx b/libbuild2/cxx/target.hxx
index fc85f75..06e8a67 100644
--- a/libbuild2/cxx/target.hxx
+++ b/libbuild2/cxx/target.hxx
@@ -7,7 +7,6 @@
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
 
-#include <libbuild2/target.hxx>
 #include <libbuild2/cc/target.hxx>
 
 #include <libbuild2/cxx/export.hxx>
@@ -104,6 +103,25 @@ namespace build2
     public:
       static const target_type static_type;
     };
+
+    // This is an abstract base target for deriving additional targets (for
+    // example, Qt moc{}) that can be #include'd in C++ translation units. In
+    // particular, only such targets will be considered to reverse-lookup
+    // extensions to target types (see dyndep_rule::map_extension() for
+    // background).
+    //
+    class LIBBUILD2_CXX_SYMEXPORT cxx_inc: public cc::cc
+    {
+    public:
+      cxx_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;
+    };
   }
 }
 
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