From bd3fb4a1324228b768bfa1f34ab4ce12539eb45b Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sat, 19 May 2018 09:18:29 +0200
Subject: Add manifest{} target type ('manifest' file name automatically mapped
 as such)

---
 build2/context.cxx |  5 +++++
 build2/target.cxx  | 44 ++++++++++++++++++++++++++++++++++++++++++++
 build2/target.hxx  | 17 +++++++++++++++--
 buildfile          |  2 +-
 4 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/build2/context.cxx b/build2/context.cxx
index 7067d8f..95230a6 100644
--- a/build2/context.cxx
+++ b/build2/context.cxx
@@ -526,6 +526,11 @@ namespace build2
       t.insert<man1>  ();
 
       {
+        auto& tt (t.insert<manifest> ());
+        t.insert_file ("manifest", tt);
+      }
+
+      {
         auto& tt (t.insert<buildfile> ());
         t.insert_file ("buildfile", tt);
       }
diff --git a/build2/target.cxx b/build2/target.cxx
index 201bd15..13db67e 100644
--- a/build2/target.cxx
+++ b/build2/target.cxx
@@ -1035,4 +1035,48 @@ namespace build2
     &file_search,
     false
   };
+
+  static const char*
+  manifest_target_extension (const target_key& tk)
+  {
+    // If the name is special 'manifest', then there is no extension,
+    // otherwise it is .manifest.
+    //
+    return *tk.name == "manifest" ? "" : "manifest";
+  }
+
+  static bool
+  manifest_target_pattern (const target_type&,
+                           const scope&,
+                           string& v,
+                           bool r)
+  {
+    size_t p (path::traits::find_extension (v));
+
+    if (r)
+    {
+      assert (p != string::npos);
+      v.resize (p);
+    }
+    else if (p == string::npos && v != "manifest")
+    {
+      v += ".manifest";
+      return true;
+    }
+
+    return false;
+  }
+
+  const target_type manifest::static_type
+  {
+    "manifest",
+    &doc::static_type,
+    &target_factory<manifest>,
+    &manifest_target_extension,
+    nullptr, /* default_extension */
+    &manifest_target_pattern,
+    nullptr,
+    &file_search,
+    false
+  };
 }
diff --git a/build2/target.hxx b/build2/target.hxx
index 2f32064..05a748c 100644
--- a/build2/target.hxx
+++ b/build2/target.hxx
@@ -1626,8 +1626,6 @@ namespace build2
 
   // Common documentation file targets.
   //
-  // @@ Maybe these should be in the built-in doc module?
-  //
   class doc: public file
   {
   public:
@@ -1692,6 +1690,21 @@ namespace build2
     virtual const target_type& dynamic_type () const {return static_type;}
   };
 
+  // We derive manifest from doc rather than file so that it get automatically
+  // installed into the same place where the rest of the documentation goes.
+  // If you think about it, it's kind of a documentation, similar to (but
+  // better than) the version file that many projects come with.
+  //
+  class manifest: public doc
+  {
+  public:
+    using doc::doc;
+
+  public:
+    static const target_type static_type;
+    virtual const target_type& dynamic_type () const {return static_type;}
+  };
+
   // Common implementation of the target factory, extension, and search
   // functions.
   //
diff --git a/buildfile b/buildfile
index 7c129d8..38c95ce 100644
--- a/buildfile
+++ b/buildfile
@@ -4,7 +4,7 @@
 
 ./: {*/ -build/ -config/ -old-tests/}                             \
     doc{INSTALL LICENSE NEWS README version}                      \
-    file{INSTALL.cli bootstrap* config.guess config.sub manifest}
+    file{INSTALL.cli bootstrap* config.guess config.sub} manifest
 
 # The version file is auto-generated (by the version module) from manifest.
 # Include it in distribution and don't remove when cleaning in src (so that
-- 
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