some code touch on process management

moo/kernel/System.moo

@@ -207,14 +207,14 @@ class System(Apex)
 			 3 ..  -> other processes started by application.
 			*/
 /* TODO: this loop is error-prone as it can't handle when the processs id wraps back and the id of gcfin_proc and ossig_proc gets bigger than normal child processes */
-			//proc := System _findProcessByIdGreaterThan: self.ossig_pid.
+			//proc := System _findNextProcess: self.ossig_pid.
-			proc := System _findProcessByIdGreaterThan: -1.
+			proc := System _findNextProcess: -1.
 			while (proc notError)
 			{
 				pid := proc id.
 				System logNl: ("Requesting to terminate process of id - " & pid asString).
 				proc terminate.
-				proc := System _findProcessByIdGreaterThan: pid.
+				proc := System _findNextProcess: pid.
 			}.
 
 			System logNl: 'Requesting to terminate the caller process of id ' & (caller id) asString.
@@ -236,7 +236,7 @@ class System(Apex)
 	method(#class,#primitive) _halting.
 	method(#class,#primitive) _toggleProcessSwitching: v.
 	method(#class,#primitive,#lenient) _findProcessById: id.
-	method(#class,#primitive,#lenient) _findProcessByIdGreaterThan: id.
+	method(#class,#primitive,#lenient) _findNextProcess: id.
 
 	method(#class,#primitive) _popCollectable.
 	method(#class,#primitive) collectGarbage.

moo/lib/exec.c

@@ -1628,7 +1628,7 @@ static moo_oop_process_t start_initial_process (moo_t* moo, moo_oop_context_t c)
 	MOO_ASSERT (moo, moo->processor->runnable.count == MOO_SMOOI_TO_OOP(0));
 	MOO_ASSERT (moo, moo->processor->active == moo->nil_process);
 
-	proc = make_process(moo, c, 2);
+	proc = make_process(moo, c, MOO_OBJ_FLAGS_PROC_SYSTEM);
 	if (!proc) return MOO_NULL;
 
 	chain_into_processor (moo, proc, PROC_STATE_RUNNING);
@@ -3342,7 +3342,58 @@ static moo_pfrc_t pf_system_find_process_by_id (moo_t* moo, moo_mod_t* mod, moo_
 	return MOO_PF_FAILURE;
 }
 
-static moo_pfrc_t pf_system_find_process_by_id_gt (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
+
+static MOO_INLINE moo_oop_t __find_adjacent_process_by_id_noseterr (moo_t* moo, moo_ooi_t index, int find_next, int exclude_system)
+{
+	if (find_next)
+	{
+		if (index < -1) index = -1;
+
+	/* TOOD: enhance alloc_pid() and free_pid() to maintain the hightest pid number so that this loop can stop before reaching proc_map_capa */
+		for (++index; index < moo->proc_map_capa; index++)
+		{
+			/* note the free slot contains a small integer which indicate the next slot index in proc_map.
+			 * if the slot it taken, it should point to a process object. read the comment at end of this loop. */
+			moo_oop_t tmp;
+
+			tmp = moo->proc_map[index];
+			if (MOO_CLASSOF(moo, tmp) == moo->_process)
+			{
+				if (exclude_system && MOO_OBJ_GET_FLAGS_PROC(tmp) == MOO_OBJ_FLAGS_PROC_SYSTEM) continue;
+				MOO_ASSERT (moo, MOO_OBJ_GET_FLAGS_PROC(tmp) == MOO_OBJ_FLAGS_PROC_NORMAL);
+				return tmp;
+			}
+
+			/* it must be in a free list since the pid slot is not allocated. see alloc_pid() and free_pid() */
+			MOO_ASSERT (moo, MOO_OOP_IS_SMOOI(moo->proc_map[index]));
+		}
+	}
+	else
+	{
+		/* find the previous one */
+
+		if (index > moo->proc_map_capa || index <= -1) index = moo->proc_map_capa;
+		for (--index; index >= 0; index--)
+		{
+			moo_oop_t tmp;
+
+			tmp = moo->proc_map[index];
+			if (MOO_CLASSOF(moo, tmp) == moo->_process)
+			{
+				if (exclude_system && MOO_OBJ_GET_FLAGS_PROC(tmp) == MOO_OBJ_FLAGS_PROC_SYSTEM) continue;
+				MOO_ASSERT (moo, MOO_OBJ_GET_FLAGS_PROC(tmp) == MOO_OBJ_FLAGS_PROC_NORMAL);
+				return tmp;
+			}
+
+			/* it must be in a free list since the pid slot is not allocated. see alloc_pid() and free_pid() */
+			MOO_ASSERT (moo, MOO_OOP_IS_SMOOI(moo->proc_map[index]));
+		}
+	}
+
+	return MOO_NULL;
+}
+
+static moo_pfrc_t pf_system_find_next_process (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
 {
 	moo_oop_t /*rcv,*/ id;
 
@@ -3351,28 +3402,25 @@ static moo_pfrc_t pf_system_find_process_by_id_gt (moo_t* moo, moo_mod_t* mod, m
 
 	/*MOO_PF_CHECK_RCV (moo, rcv == (moo_oop_t)moo->processor);*/
 
+	if (id == moo->_nil)
+	{
+		id = MOO_SMOOI_TO_OOP(-1);
+	}
+	else if (MOO_CLASSOF(moo, id) == moo->_process)
+	{
+		/* the argument is a process object */
+		id = ((moo_oop_process_t)id)->id;
+	}
+
 	if (MOO_OOP_IS_SMOOI(id))
 	{
-		moo_ooi_t index = MOO_OOP_TO_SMOOI(id);
+		moo_oop_t tmp;
-		if (index >= -1) /* allow -1 to be able to return pid 0. */
+
+		tmp = __find_adjacent_process_by_id_noseterr(moo, MOO_OOP_TO_SMOOI(id), 1, 1);
+		if (tmp)
 		{
-/* TOOD: enhance alloc_pid() and free_pid() to maintain the hightest pid number so that this loop can stop before reaching proc_map_capa */
+			MOO_STACK_SETRET (moo, nargs, tmp);
-			for (++index; index < moo->proc_map_capa; index++)
+			return MOO_PF_SUCCESS;
-			{
-				/* note the free slot contains a small integer which indicate the next slot index in proc_map.
-				 * if the slot it taken, it should point to a process object. read the comment at end of this loop. */
-				moo_oop_t tmp;
-
-				tmp = moo->proc_map[index];
-				if (MOO_CLASSOF(moo, tmp) == moo->_process && MOO_OBJ_GET_FLAGS_PROC(tmp) == 1) /* normal process only. skip a system process	 */
-				{
-					MOO_STACK_SETRET (moo, nargs, tmp);
-					return MOO_PF_SUCCESS;
-				}
-
-				/* it must be in a free list since the pid slot is not allocated. see alloc_pid() and free_pid() */
-				MOO_ASSERT (moo, MOO_OOP_IS_SMOOI(moo->proc_map[index]));
-			}
 		}
 	}
 
@@ -3380,7 +3428,6 @@ static moo_pfrc_t pf_system_find_process_by_id_gt (moo_t* moo, moo_mod_t* mod, m
 	return MOO_PF_FAILURE;
 }
 
-
 /* ------------------------------------------------------------------ */
 static moo_pfrc_t pf_number_scale (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
 {
@@ -4497,8 +4544,8 @@ static pf_t pftab[] =
 	{ "System_calloc",                         { moo_pf_system_calloc,                    1, 1 } },
 	{ "System_calloc:",                        { moo_pf_system_calloc,                    1, 1 } },
 	{ "System_collectGarbage",                 { moo_pf_system_collect_garbage,           0, 0 } },
+	{ "System_findNextProcess:",               { pf_system_find_next_process,             1, 1 } },
 	{ "System_findProcessById:",               { pf_system_find_process_by_id,            1, 1 } },
-	{ "System_findProcessByIdGreaterThan:",    { pf_system_find_process_by_id_gt,         1, 1 } },
 	{ "System_free",                           { moo_pf_system_free,                      1, 1 } },
 	{ "System_free:",                          { moo_pf_system_free,                      1, 1 } },
 	{ "System_gc",                             { moo_pf_system_collect_garbage,           0, 0 } },

moo/lib/moo.h

@@ -376,6 +376,10 @@ typedef enum moo_gcfin_t moo_gcfin_t;
 #define MOO_OBJ_FLAGS_HASH_CALLED 1 /* the hash method has been invoked for this object  */
 #define MOO_OBJ_FLAGS_HASH_STORED 2 /* the object with hash invoke has been moved by GC  */
 
+#define MOO_OBJ_FLAGS_PROC_NOT    0  /* not process */
+#define MOO_OBJ_FLAGS_PROC_NORMAL 1  /* normal process spawned with a block sent newProcess: */
+#define MOO_OBJ_FLAGS_PROC_SYSTEM 2  /* internal process */
+
 #define MOO_OBJ_HEADER \
 	moo_oow_t _flags; \
 	moo_oow_t _size; \