Enhancements

Add mutex lock to prevent reading and writing a cached file at the same time.
Optimize codes.

src/misc.cpp

@@ -711,10 +711,11 @@ std::string fileGet(const std::string &path, bool scope_limit)
         std::fseek(fp, 0, SEEK_END);
         long tot = std::ftell(fp);
         char *data = new char[tot + 1];
+        data[tot] = '\0';
         std::rewind(fp);
         std::fread(&data[0], 1, tot, fp);
         std::fclose(fp);
-        content.append(data, 0, tot);
+        content.assign(data, tot);
         delete[] data;
     }