From 52c1c81918c23da3007db0ff8fa39c9e95cd69af Mon Sep 17 00:00:00 2001
From: Vladimir Prus <ghost@cs.msu.su>
Date: Thu, 4 Mar 2010 23:02:57 +0000
Subject: [PATCH] Implement PRECIOUS builtin.

Note that existing code already tried to assume that the 'together'
flag means precious, but as described at:
http://public.perforce.com:8080/@md=d&cd=//public/jam/src/&cdf=//public/jam/src/make1.c&c=klD@/1494?ac=10
this was not really wrong.

Now, PRECIOUS makes the target never removed. I plan to extend it so that
user can control what exit codes cause the target to be removed.


[SVN r60157]
---
 historic/jam/src/builtins.c | 20 ++++++++++++++++++++
 historic/jam/src/builtins.h |  1 +
 historic/jam/src/make1.c    | 12 ++++++++++--
 historic/jam/src/rules.h    |  2 ++
 4 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/historic/jam/src/builtins.c b/historic/jam/src/builtins.c
index 66d178af7..4f94edc3a 100644
--- a/historic/jam/src/builtins.c
+++ b/historic/jam/src/builtins.c
@@ -375,6 +375,12 @@ void load_builtins()
                         builtin_pad, 0, args );
       }
 
+      {
+          char * args[] = { "targets", "*", 0 };
+          bind_builtin( "PRECIOUS",
+                        builtin_precious, 0, args );
+      }
+
       /* Initialize builtin modules. */
       init_set();
       init_path();
@@ -1685,6 +1691,20 @@ LIST *builtin_pad( PARSE *parse, FRAME *frame )
     }
 }
 
+LIST *builtin_precious( PARSE *parse, FRAME *frame )
+{
+    LIST* targets = lol_get(frame->args, 0);
+
+    for ( ; targets; targets = list_next( targets ) )    
+    {
+        TARGET* t = bindtarget (targets->string);
+        t->flags |= T_FLAG_PRECIOUS;
+    }
+
+    return L0;
+}
+
+
 #ifdef HAVE_PYTHON
 
 LIST * builtin_python_import_rule( PARSE * parse, FRAME * frame )
diff --git a/historic/jam/src/builtins.h b/historic/jam/src/builtins.h
index ba37b87ea..1edaab738 100644
--- a/historic/jam/src/builtins.h
+++ b/historic/jam/src/builtins.h
@@ -59,6 +59,7 @@ LIST *builtin_shell( PARSE *parse, FRAME *frame );
 LIST *builtin_md5( PARSE *parse, FRAME *frame );
 LIST *builtin_file_open( PARSE *parse, FRAME *frame );
 LIST *builtin_pad( PARSE *parse, FRAME *frame );
+LIST *builtin_precious( PARSE *parse, FRAME *frame );
 
 void backtrace( FRAME *frame );
 
diff --git a/historic/jam/src/make1.c b/historic/jam/src/make1.c
index 26ee5c41e..8001f3339 100644
--- a/historic/jam/src/make1.c
+++ b/historic/jam/src/make1.c
@@ -839,12 +839,20 @@ static void make1d( state * pState )
     /* If the command was interrupted or failed and the target is not
      * "precious", remove the targets.
      */
-    if ( ( status != EXEC_CMD_OK ) && !( cmd->rule->actions->flags & RULE_TOGETHER ) )
+    if (status != EXEC_CMD_OK) 
     {
         LIST * targets = lol_get( &cmd->args, 0 );
         for ( ; targets; targets = list_next( targets ) )
-            if ( !unlink( targets->string ) )
+        {
+            int need_unlink = 1;
+            TARGET* t = bindtarget ( targets->string );
+            if (t->flags & T_FLAG_PRECIOUS)
+            {                
+                need_unlink = 0;
+            }
+            if (need_unlink && !unlink( targets->string ) )
                 printf( "...removing %s\n", targets->string );
+        }
     }
 
     /* Free this command and call make1c() to move onto the next one scheduled
diff --git a/historic/jam/src/rules.h b/historic/jam/src/rules.h
index 9ad4171b6..78e056202 100644
--- a/historic/jam/src/rules.h
+++ b/historic/jam/src/rules.h
@@ -166,6 +166,8 @@ struct _target
  */
 #define T_FLAG_ISFILE         0x0400
 
+#define T_FLAG_PRECIOUS       0x0800 
+
     char       binding;               /* how target relates to a real file or
                                        * folder
                                        */