fix issues #581: nested timeouts canceled each-other

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/util/cancel_eh.h

@@ -26,12 +26,14 @@ Revision History:
 */
 template<typename T>
 class cancel_eh : public event_handler {
+    bool m_canceled;
     T & m_obj;
 public:
-    cancel_eh(T & o):m_obj(o) {}
-    ~cancel_eh() { m_obj.reset_cancel(); }
+    cancel_eh(T & o): m_canceled(false), m_obj(o) {}
+    ~cancel_eh() { if (m_canceled) m_obj.dec_cancel(); }
     virtual void operator()() { 
-        m_obj.cancel(); 
+        m_canceled = true;
+        m_obj.inc_cancel(); 
     }
 };
 

src/util/rlimit.cpp

@@ -31,7 +31,7 @@ uint64 reslimit::count() const {
 
 bool reslimit::inc() {
     ++m_count;
-    return !m_cancel && (m_limit == 0 || m_count <= m_limit);
+    return m_cancel == 0 && (m_limit == 0 || m_count <= m_limit);
 }
 
 bool reslimit::inc(unsigned offset) {
@@ -46,7 +46,7 @@ void reslimit::push(unsigned delta_limit) {
     }
     m_limits.push_back(m_limit);
     m_limit = m_limit==0?new_limit:std::min(new_limit, m_limit);
-    m_cancel = false;
+    m_cancel = 0;
 }
 
 void reslimit::pop() {
@@ -55,11 +55,11 @@ void reslimit::pop() {
     }
     m_limit = m_limits.back();
     m_limits.pop_back();
-    m_cancel = false;
+    m_cancel = 0;
 }
 
 char const* reslimit::get_cancel_msg() const {
-    if (m_cancel) {
+    if (m_cancel > 0) {
         return Z3_CANCELED_MSG;
     }
     else {
@@ -84,7 +84,7 @@ void reslimit::pop_child() {
 void reslimit::cancel() {
     #pragma omp critical (reslimit_cancel)
     {
-        set_cancel(true);
+        set_cancel(m_cancel+1);
     }
 }
 
@@ -92,11 +92,28 @@ void reslimit::cancel() {
 void reslimit::reset_cancel() {
     #pragma omp critical (reslimit_cancel)
     {
-        set_cancel(false);
+        set_cancel(0);
     }
 }
 
-void reslimit::set_cancel(bool f) { 
+void reslimit::inc_cancel() {
+    #pragma omp critical (reslimit_cancel)
+    {        
+        set_cancel(m_cancel+1);
+    }
+}
+
+
+void reslimit::dec_cancel() {
+    #pragma omp critical (reslimit_cancel)
+    {
+        if (m_cancel > 0) {
+            set_cancel(m_cancel-1);
+        }
+    }
+}
+
+void reslimit::set_cancel(unsigned f) { 
     m_cancel = f; 
     for (unsigned i = 0; i < m_children.size(); ++i) {
         m_children[i]->set_cancel(f);

src/util/rlimit.h

@@ -22,13 +22,13 @@ Revision History:
 #include "vector.h"
 
 class reslimit {
-    volatile bool   m_cancel;
+    volatile unsigned   m_cancel;
     uint64          m_count;
     uint64          m_limit;
     svector<uint64> m_limits;
     ptr_vector<reslimit> m_children;
 
-    void set_cancel(bool f);
+    void set_cancel(unsigned f);
     
 public:    
     reslimit();
@@ -42,10 +42,13 @@ public:
     uint64 count() const; 
 
 
-    bool get_cancel_flag() const { return m_cancel; }
+    bool get_cancel_flag() const { return m_cancel > 0; }
     char const* get_cancel_msg() const;
     void cancel();
     void reset_cancel();
+
+    void inc_cancel();
+    void dec_cancel();
 };
 
 class scoped_rlimit {