Store position in VirtualMachine

Author: adazem009

src/engine/engine.cpp

@@ -123,9 +123,7 @@ void Engine::frame()
         m_breakFrame = false;
 
         do {
-            auto ret = script->run(m_scriptPositions[i]);
-            if (script->savePos())
-                m_scriptPositions[i] = ret;
+            script->run();
             if (script->atEnd()) {
                 for (auto &[key, value] : m_broadcastMap)
                     value.erase(std::remove(value.begin(), value.end(), script->script()), value.end());
@@ -144,7 +142,6 @@ void Engine::frame()
         }
         assert(index != -1);
         m_runningScripts.erase(m_runningScripts.begin() + index);
-        m_scriptPositions.erase(m_scriptPositions.begin() + index);
     }
     m_scriptsToRemove.clear();
 }
@@ -166,7 +163,6 @@ void Engine::start()
 void Engine::stop()
 {
     m_runningScripts.clear();
-    m_scriptPositions.clear();
 }
 
 /*! Starts a script with the given top level block as the given Target (a sprite or the stage). */
@@ -186,7 +182,6 @@ void Engine::startScript(std::shared_ptr<Block> topLevelBlock, std::shared_ptr<T
     if (topLevelBlock->next()) {
         auto script = m_scripts[topLevelBlock];
         m_runningScripts.push_back(script->start());
-        m_scriptPositions.push_back(script->bytecode());
     }
 }
 
@@ -204,12 +199,11 @@ void libscratchcpp::Engine::broadcast(unsigned int index, VirtualMachine *source
         }
         if (index != -1) {
             // Reset the script if it's already running
-            m_scriptPositions[index] = m_runningScripts[index]->bytecode();
+            m_runningScripts[index]->reset();
             if (script == sourceScript->script())
                 sourceScript->stop(false, true);
         } else {
             m_runningScripts.push_back(script->start());
-            m_scriptPositions.push_back(script->bytecode());
         }
     }
 }

src/engine/engine.h

@@ -77,7 +77,6 @@ class LIBSCRATCHCPP_EXPORT Engine
         std::unordered_map<unsigned int, std::vector<Script *>> m_broadcastMap;
         std::vector<std::string> m_extensions;
         std::vector<std::shared_ptr<VirtualMachine>> m_runningScripts;
-        std::vector<unsigned int *> m_scriptPositions;
         std::vector<VirtualMachine *> m_scriptsToRemove;
         std::unordered_map<std::shared_ptr<Block>, std::shared_ptr<Script>> m_scripts;
         std::vector<BlockFunc> m_functions;

src/engine/virtualmachine.cpp

@@ -149,15 +149,25 @@ void VirtualMachine::setLists(List **lists)
 void VirtualMachine::setBytecode(unsigned int *code)
 {
     m_bytecode = code;
+    m_pos = code;
 }
 
-/*! Runs the script. */
-unsigned int *VirtualMachine::run()
+/*! Continues running the script from last position (the first instruction is skipped). */
+void VirtualMachine::run()
 {
-    return run(m_bytecode);
+    unsigned int *ret = run(m_pos);
+    assert(ret);
+    if (m_savePos)
+        m_pos = ret;
+}
+
+/*! Jumps back to the initial position. */
+void VirtualMachine::reset()
+{
+    assert(m_bytecode);
+    m_pos = m_bytecode;
 }
 
-/*! Continues running the script from the given position (the first instruction is skipped). */
 unsigned int *VirtualMachine::run(unsigned int *pos)
 {
     static const void *dispatch_table[] = {

src/engine/virtualmachine.h

@@ -111,8 +111,8 @@ class LIBSCRATCHCPP_EXPORT VirtualMachine
         void addReturnValue(const Value &v) { *m_regs[m_regCount++] = v; };
         void replaceReturnValue(const Value &v, unsigned int offset) { *m_regs[m_regCount - offset] = v; };
 
-        unsigned int *run();
-        unsigned int *run(unsigned int *pos);
+        void run();
+        void reset();
 
         /*!
          * Use this to stop the script from a function.
@@ -134,10 +134,12 @@ class LIBSCRATCHCPP_EXPORT VirtualMachine
         /*! Returns true if the VM has reached the vm::OP_HALT instruction. */
         bool atEnd() const { return m_atEnd; };
 
-        /*! Used by Engine to check whether the position can be preserved. */
+        /*! Used to check whether the position can be preserved. */
         bool savePos() const { return m_savePos; }
 
     private:
+        unsigned int *run(unsigned int *pos);
+
         static const unsigned int instruction_arg_count[];
 
         typedef struct
@@ -153,6 +155,7 @@ class LIBSCRATCHCPP_EXPORT VirtualMachine
         Target *m_target = nullptr;
         Engine *m_engine = nullptr;
         Script *m_script = nullptr;
+        unsigned int *m_pos = nullptr;
         bool m_atEnd = false;
         std::vector<Loop> m_loops;
         std::vector<unsigned int *> m_callTree;