* vm.c (ruby_vm_at_exit): new API. This enables extension libs to

hook a VM termination.  Right now, because the VM we have is
	  process global, most extensions do not deallocate resources and
	  leave them to Operating System's reaping userland processes.  But
	  in a future we plan to have multiple VMs to run simultaneously in
	  a single process (MVM project).  At that stage we can no longer
	  rely on OSes and have to manage every resources to be reclaimed
	  properly.  So it is.  For a forward-compatibility reason this API
	  is introduced now, encouraging you to be as gentle as you can for
	  your resources; that is, tidy up your room.

	* include/ruby/vm.h: ditto.

	* vm_core.h (rb_vm_struct): new field.

	* vm.c (vm_init2): initialize above new field.

	* eval.c (ruby_cleanup): trigger those hooks.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30050 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,24 @@
+Thu Dec  2 19:58:24 2010  URABE Shyouhei  <shyouhei@ruby-lang.org>
+
+	* vm.c (ruby_vm_at_exit): new API.  This enables extension libs to
+	  hook a VM termination.  Right now, because the VM we have is
+	  process global, most extensions do not deallocate resources and
+	  leave them to Operating System's reaping userland processes.  But
+	  in a future we plan to have multiple VMs to run simultaneously in
+	  a single process (MVM project).  At that stage we can no longer
+	  rely on OSes and have to manage every resources to be reclaimed
+	  properly.  So it is.  For a forward-compatibility reason this API
+	  is introduced now, encouraging you to be as gentle as you can for
+	  your resources; that is, tidy up your room.
+
+	* include/ruby/vm.h: ditto.
+
+	* vm_core.h (rb_vm_struct): new field.
+
+	* vm.c (vm_init2): initialize above new field.
+
+	* eval.c (ruby_cleanup): trigger those hooks.
+
 Thu Dec  2 17:00:44 2010  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c: parenthesize macro arguments.

eval.c

@@ -129,6 +129,9 @@ ruby_cleanup(volatile int ex)
     int nerr;
     void rb_threadptr_interrupt(rb_thread_t *th);
     void rb_threadptr_check_signal(rb_thread_t *mth);
+    int i;
+    rb_vm_t *vm = GET_VM();
+    VALUE ary = (VALUE)&vm->at_exit;
 
     rb_threadptr_interrupt(th);
     rb_threadptr_check_signal(th);
@@ -148,6 +151,13 @@ ruby_cleanup(volatile int ex)
     }
     POP_TAG();
 
+    /* at_exit functions called here; any other place more apropriate
+     * for this purpose? let me know if any. */
+    for (i=0; i<RARRAY_LEN(ary); i++) {
+       ((void(*)(rb_vm_t*))RARRAY_PTR(ary)[i])(vm);
+    }
+    rb_ary_clear(ary);
+
     errs[0] = th->errinfo;
     PUSH_TAG();
     if ((state = EXEC_TAG()) == 0) {

include/ruby/vm.h

@@ -36,6 +36,24 @@ typedef struct rb_vm_struct ruby_vm_t;
 /* core API */
 int ruby_vm_destruct(ruby_vm_t *vm);
 
+/**
+ * ruby_vm_at_exit registers a function _func_ to be invoked when a VM
+ * passed away.  Functions registered this way runs in reverse order
+ * of registration, just like END {} block does.  The difference is
+ * its timing to be triggered. ruby_vm_at_exit functions runs when a
+ * VM _passed_ _away_, while END {} blocks runs just _before_ a VM
+ * _is_ _passing_ _away_.
+ *
+ * You cannot register a function to another VM than where you are in.
+ * So where to register is intuitive, omitted.  OTOH the argument
+ * _func_ cannot know which VM it is in because at the time of
+ * invocation, the VM has already died and there is no execution
+ * context.  The VM itself is passed as the first argument to it.
+ *
+ * @param[in] func the function to register.
+ */
+void ruby_vm_at_exit(void(*func)(ruby_vm_t *));
+
 #if defined __GNUC__ && __GNUC__ >= 4
 #pragma GCC visibility pop
 #endif

vm.c

@@ -173,6 +173,14 @@ vm_get_ruby_level_caller_cfp(rb_thread_t *th, rb_control_frame_t *cfp)
     return 0;
 }
 
+/* at exit */
+
+void
+ruby_vm_at_exit(void (*func)(rb_vm_t *))
+{
+    rb_ary_push((VALUE)&GET_VM()->at_exit, (VALUE)func);
+}
+
 /* Env */
 
 /*
@@ -1572,6 +1580,8 @@ vm_init2(rb_vm_t *vm)
 {
     MEMZERO(vm, rb_vm_t, 1);
     vm->src_encoding_index = -1;
+    vm->at_exit.basic.flags = (T_ARRAY | RARRAY_EMBED_FLAG) & ~RARRAY_EMBED_LEN_MASK; /* len set 0 */
+    vm->at_exit.basic.klass = 0;
 }
 
 /* Thread */

vm_core.h

@@ -317,6 +317,12 @@ typedef struct rb_vm_struct {
 #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
     struct rb_objspace *objspace;
 #endif
+
+    /*
+     * @shyouhei notes that this is not for storing normal Ruby
+     * objects so do *NOT* mark this when you GC.
+     */
+    struct RArray at_exit;
 } rb_vm_t;
 
 typedef struct {