common taskScheduler: thread sync optmization

replaced future/promise with mutex since they use a lot of memory allocation number.

plus, binary size is reduced from 2094896 -> 1746864

src/lib/sw_engine/tvgSwRenderer.cpp

@@ -139,7 +139,7 @@ SwRenderer::~SwRenderer()
 
 bool SwRenderer::clear()
 {
-    for (auto task : tasks) task->get();
+    for (auto task : tasks) task->done();
     tasks.clear();
 
     return true;
@@ -181,7 +181,7 @@ bool SwRenderer::postRender()
 bool SwRenderer::render(const Shape& shape, void *data)
 {
     auto task = static_cast<SwTask*>(data);
-    task->get();
+    task->done();
 
     uint8_t r, g, b, a;
     if (auto fill = task->sdata->fill()) {
@@ -205,7 +205,7 @@ bool SwRenderer::dispose(TVG_UNUSED const Shape& sdata, void *data)
     auto task = static_cast<SwTask*>(data);
     if (!task) return true;
 
-    task->get();
+    task->done();
     shapeFree(&task->shape);
     if (task->transform) free(task->transform);
     delete(task);
@@ -226,13 +226,13 @@ void* SwRenderer::prepare(const Shape& sdata, void* data, const RenderTransform*
     if (flags == RenderUpdateFlag::None) return task;
 
     //Finish previous task if it has duplicated request.
-    if (task->valid()) task->get();
+    task->done();
 
     task->sdata = &sdata;
 
     if (compList.size() > 0) {
         //Guarantee composition targets get ready.
-        for (auto comp : compList)  static_cast<SwTask*>(comp.edata)->get();
+        for (auto comp : compList)  static_cast<SwTask*>(comp.edata)->done();
         task->compList.assign(compList.begin(), compList.end());
     }
 

src/lib/tvgTaskScheduler.cpp

@@ -22,6 +22,8 @@
 #include <deque>
 #include <thread>
 #include <vector>
+#include <atomic>
+#include <condition_variable>
 #include "tvgTaskScheduler.h"
 
 /************************************************************************/
@@ -179,7 +181,12 @@ void TaskScheduler::term()
 
 void TaskScheduler::request(Task* task)
 {
-    if (inst) {
-        inst->request(task);
-    }
+    if (inst) inst->request(task);
+}
+
+
+unsigned TaskScheduler::threads()
+{
+    if (inst) return inst->threadCnt;
+    return 0;
 }

src/lib/tvgTaskScheduler.h

@@ -22,31 +22,40 @@
 #ifndef _TVG_TASK_SCHEDULER_H_
 #define _TVG_TASK_SCHEDULER_H_
 
-#include <future>
+#include <mutex>
 #include "tvgCommon.h"
 
 namespace tvg
 {
 
+struct Task;
+
+struct TaskScheduler
+{
+    static unsigned threads();
+    static void init(unsigned threads);
+    static void term();
+    static void request(Task* task);
+};
+
 struct Task
 {
 private:
-    promise<void> sender;
-    future<void>  receiver;
+    mutex mtx;
+    bool working = false;
 
 public:
     virtual ~Task() = default;
 
-    void get()
+    void done()
     {
-        if (receiver.valid()) {
-            receiver.get();
-        }
-    }
+        if (!working) return;
 
-    bool valid()
-    {
-        return receiver.valid();
+        if (TaskScheduler::threads() > 0) {
+            mtx.lock();
+            working = false;
+            mtx.unlock();
+        }
     }
 
 protected:
@@ -56,24 +65,22 @@ private:
     void operator()(unsigned tid)
     {
         run(tid);
-        sender.set_value();
+
+        if (TaskScheduler::threads() > 0) mtx.unlock();
     }
 
     void prepare()
     {
-        sender = promise<void>();
-        receiver = sender.get_future();
+        if (TaskScheduler::threads() > 0) {
+            working = true;
+            mtx.lock();
+        }
     }
 
     friend class TaskSchedulerImpl;
 };
 
-struct TaskScheduler
-{
-    static void init(unsigned threads);
-    static void term();
-    static void request(Task* task);
-};
+
 
 }
 

src/loaders/svg/tvgSvgLoader.cpp

@@ -2518,7 +2518,7 @@ bool SvgLoader::read()
 
 bool SvgLoader::close()
 {
-    this->get();
+    this->done();
 
     if (loaderData.svgParse) {
         free(loaderData.svgParse);
@@ -2541,7 +2541,7 @@ bool SvgLoader::close()
 
 unique_ptr<Scene> SvgLoader::data()
 {
-    this->get();
+    this->done();
     if (root) return move(root);
     else return nullptr;
 }