From 774bfb559ecaef2aac1dcb7a0414bc6895a9b9d5 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 17 Jun 2016 16:42:38 +0200
Subject: Initial take on DLL support for MinGW toolchain

---
 build2/algorithm.cxx | 89 ++++++++++++++++++++++++++++++++--------------------
 1 file changed, 55 insertions(+), 34 deletions(-)

(limited to 'build2/algorithm.cxx')

diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index a22837f..17768e3 100644
--- a/build2/algorithm.cxx
+++ b/build2/algorithm.cxx
@@ -478,60 +478,81 @@ namespace build2
   }
 
   target_state
-  perform_clean (action a, target& t)
+  clean_extra (action a, file& ft, initializer_list<const char*> es)
   {
-    // The reverse order of update: first remove the file, then clean
-    // prerequisites.
+    // Clean the extras first and don't print the commands at verbosity level
+    // below 3.
     //
-    file& ft (dynamic_cast<file&> (t));
+    target_state er (target_state::unchanged);
+    path ef; // First extra file that actually got removed (see below).
 
-    target_state r (rmfile (ft.path (), ft)
-                    ? target_state::changed
-                    : target_state::unchanged);
+    for (const char* e: es)
+    {
+      if (e == nullptr)
+        continue;
 
-    // Update timestamp in case there are operations after us that
-    // could use the information.
-    //
-    ft.mtime (timestamp_nonexistent);
+      path f;
+      if (*e == '+')
+        f = ft.path () + ++e;
+      else
+        f = ft.path ().base () + e;
 
-    // Clean prerequisites.
-    //
-    r |= reverse_execute_prerequisites (a, t);
+      target_state r (rmfile (f, false)
+                      ? target_state::changed
+                      : target_state::unchanged);
 
-    return r;
-  }
+      if (r == target_state::changed && ef.empty ())
+      {
+        ef = move (f);
+      }
 
-  target_state
-  perform_clean_depdb (action a, target& t)
-  {
-    // Normally the .d file is created/updated before the target so remove it
-    // first. Also, don't print the command at verbosity level below 3.
-    //
-    file& ft (dynamic_cast<file&> (t));
+      er |= r;
+    }
 
-    path df (ft.path () + ".d");
-    target_state dr (rmfile (df, false)
+    // Now clean the primary target and its prerequisited in the reverse order
+    // of update: first remove the file, then clean the prerequisites.
+    //
+    target_state tr (rmfile (ft.path (), ft)
                      ? target_state::changed
                      : target_state::unchanged);
 
-    // Factor the result of removing the .d file into the target state. While
-    // strictly speaking removing it doesn't change the target state, if we
-    // don't do this, then we may end up removing the file but still saying
-    // that everything is clean (e.g., if someone removes the target file but
-    // leaves .d laying around). That would be confusing.
+    // Update timestamp in case there are operations after us that could use
+    // the information.
+    //
+    ft.mtime (timestamp_nonexistent);
+
+    // Clean prerequisites.
     //
-    target_state tr (perform_clean (a, t));
+    tr |= reverse_execute_prerequisites (a, ft);
 
+    // Factor the result of removing the extra files into the target state.
+    // While strictly speaking removing them doesn't change the target state,
+    // if we don't do this, then we may end up removing the file but still
+    // saying that everything is clean (e.g., if someone removes the target
+    // file but leaves the extra laying around). That would be confusing.
+    //
     // What would also be confusing is if we didn't print any commands in
     // this case.
     //
-    if (tr == target_state::unchanged && dr == target_state::changed)
+    if (tr != target_state::changed && er == target_state::changed)
     {
       if (verb > 0 && verb < 3)
-        text << "rm " << df;
+        text << "rm " << ef;
     }
 
-    tr |= dr;
+    tr |= er;
     return tr;
   }
+
+  target_state
+  perform_clean (action a, target& t)
+  {
+    return clean_extra (a, dynamic_cast<file&> (t), {});
+  }
+
+  target_state
+  perform_clean_depdb (action a, target& t)
+  {
+    return clean_extra (a, dynamic_cast<file&> (t), {"+.d"});
+  }
 }
-- 
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