fix log thread bug, add clean memory button, fix pinch zoom bug, set android back button to undo

engine/log.cpp

@@ -12,7 +12,7 @@ static size_t data_handler(void *contents, size_t size, size_t nmemb, void *user
 
 void LogRemote::start()
 {
-    if (m_running)
+    if (m_running || m_error)
         return; // already running
 
     m_running = true;
@@ -20,7 +20,7 @@ void LogRemote::start()
         net_init();
         auto session_string = net_request("/start");
         m_session = atoi(session_string.c_str());
-        while (m_running)
+        while (m_running && !m_error)
         {
             auto m = m_mq.Get();
             auto escaped = curl_easy_escape(curl, m.c_str(), (int)m.size());
@@ -30,6 +30,7 @@ void LogRemote::start()
             net_request("/log", std::string(data.get(), sz));
         }
         net_close();
+        LOG("NET thread loop exit");
     });
 }
 void LogRemote::net_init()
@@ -50,7 +51,11 @@ std::string LogRemote::net_request(std::string cmd, std::string data /*= ""*/)
     curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
     res = curl_easy_perform(curl);
     if (res != CURLcode::CURLE_OK)
+    {
+        LOG("NET error, closed");
         m_running = false;
+        m_error = true;
+    }
     return readBuffer;
 }
 void LogRemote::net_close()
@@ -58,6 +63,7 @@ void LogRemote::net_close()
     if (curl)
         curl_easy_cleanup(curl);
     curl = nullptr;
+    m_running = false;
 }
 void LogRemote::log(const char* format, ...)
 {