3 files changed, 26 insertions, 10 deletions

diff --git a/includes/Task.h b/includes/Task.h
index 3219397..9539d7d 100644
--- a/includes/Task.h
+++ b/includes/Task.h
@@ -14,12 +14,15 @@ namespace Balau {
 
 namespace Events { class BaseEvent; };
 
+class Task;
+
 class EAgain : public GeneralException {
   public:
-      EAgain(Events::BaseEvent * evt) : GeneralException(), m_evt(evt) { }
     Events::BaseEvent * getEvent() { return m_evt; }
   private:
+      EAgain(Events::BaseEvent * evt) : GeneralException(), m_evt(evt) { }
     Events::BaseEvent * m_evt;
+    friend class Task;
 };
 
 class TaskSwitch : public GeneralException {
@@ -28,7 +31,6 @@ class TaskSwitch : public GeneralException {
 };
 
 class TaskMan;
-class Task;
 
 namespace Events {
 
@@ -176,8 +178,10 @@ class Task {
     };
   protected:
     void yield() throw (GeneralException) {
-        if (yield(false))
+        if (yield(false)) {
+            AAssert(!m_cannotEAgain, "task at %p in simple context mode can't EAgain", this);
             throw EAgain(NULL);
+        }
     }
     virtual void Do() = 0;
     void waitFor(Events::BaseEvent * event);
@@ -199,8 +203,10 @@ class Task {
   private:
     void yield(Events::BaseEvent * evt) throw (GeneralException) {
         waitFor(evt);
-        if (yield(false))
+        if (yield(false)) {
+            AAssert(!m_cannotEAgain, "task at %p in simple context mode can't EAgain", this);
             throw EAgain(NULL);
+        }
     }
     bool yield(bool stillRunning);
     static size_t stackSize() { return 64 * 1024; }
@@ -210,13 +216,22 @@ class Task {
     static void CALLBACK coroutineTrampoline(void *);
     void coroutine();
     bool enterSimpleContext() {
-        AAssert(!m_stackless, "You can't enter a simple context in a stackless task");
-        bool r = m_okayToEAgain;
-        m_okayToEAgain = false;
+        bool r;
+        if (m_stackless) {
+            r = m_cannotEAgain;
+            m_cannotEAgain = true;
+        } else {
+            r = m_okayToEAgain;
+            m_okayToEAgain = false;
+        }
         return r;
     }
     void leaveSimpleContext(bool oldStatus) {
-        m_okayToEAgain = oldStatus;
+        if (m_stackless) {
+            m_cannotEAgain = oldStatus;
+        } else {
+            m_okayToEAgain = oldStatus;
+        }
     }
     void * m_stack = NULL;
 #ifndef _WIN32
@@ -232,7 +247,7 @@ class Task {
     Lock m_eventLock;
     typedef std::list<Events::TaskEvent *> waitedByList_t;
     waitedByList_t m_waitedBy;
-    bool m_okayToEAgain = false, m_stackless = false;
+    bool m_okayToEAgain = false, m_stackless = false, m_cannotEAgain = false;
       Task(const Task &) = delete;
     Task & operator=(const Task &) = delete;
 };
diff --git a/src/BLua.cc b/src/BLua.cc
index 7eda510..2bc726e 100644
--- a/src/BLua.cc
+++ b/src/BLua.cc
@@ -870,7 +870,7 @@ bool Balau::Lua::yieldC() throw (GeneralException) {
     Future<int> * p = (Future<int> *) touserdata(-2);
 
     if (p->m_ranOnce)
-        throw EAgain(p->m_evt);
+        Task::operationYield(p->m_evt, Task::STACKLESS);
 
     resumeC();
     return yieldC();
diff --git a/src/Task.cc b/src/Task.cc
index ed03532..345d310 100644
--- a/src/Task.cc
+++ b/src/Task.cc
@@ -301,6 +301,7 @@ void Balau::Task::operationYield(Events::BaseEvent * evt, enum OperationYieldTyp
         return;
 
     if ((yieldType != SIMPLE) && t->m_okayToEAgain && !gotSignal && doEAgain) {
+        AAssert(!t->m_cannotEAgain, "task at %p in simple context mode can't EAgain", t);
         Printer::elog(E_TASK, "operation is throwing an EAgain exception with event %p", evt);
         throw EAgain(evt);
     }