Add runtime Lua script pre-compilation and general .luac file support (#3318) (#4119)

* [simu] simpgmspace: Populate file date/time/size  in f_stat(); Add f_utime(); Fix f_getcwd() on Windows; Fix f_mkdir() build error on Windows.

* [Lua] Add runtime support for script pre-compilation. Changes behavior with LUA_COMPILER (Re: https://github.com/opentx/opentx/issues/3318):
  All .lua scripts are now compiled and saved to binary "bytecode" file (.luac extension) upon first execution;
  Scripts are also automatically re-compiled if .lua source file is newer than existing .luac file;
  The pre-compiled .luac version is loaded if modification time is newer or equivalent to .lua source file;
  If a .luac version of a script exists, then the .lua version does not need to be present;
  Guards against bytecode compatibility issues (binaries from 64-bit sim will not run on 32-bit sim/radio);
  In SIMU and DEBUG builds, the source .lua file is always preferred in order to preserve full debug info (this is is controlled with new LUA_SCRIPT_LOAD_MODE macro, see lua_api.h);
  GC is now run after each script is loaded.

* [Lua] Add loadScript() API function as alternative to loadfile() from Lua base. This can take advantage of the new OTx script pre-compilation features to reduce memory footprint when loading functions dynamically. This is an interface to luaLoadScriptFileToState(). Fully documented.

* [SD][Lua] Flexible file extensions support:
  Allow for variable length file extensions throughout system (no longer hard-coded in LEN_FILE_EXTENSION);
  Fixes issues with renaming files in SD manager which have file extensions longer than ".ext";
  Expand general support for multiple file extensions per file type in sdListFiles() (eg. .lua and .luac for scripts);
  Lua scripts with .luac extensions can now be selected in custom/telemetry/function menus even if no .lua version exists (duplicates are not shown);
  .luac files can now also be executed from SD file manager UI.

* [Build] Added CMake options for LUA_COMPILER and LUA_SCRIPT_LOAD_MODE.

* Cosmetics.

* [SD][gui] Improve efficiency of some file name handling routines in sdmanager GUI and sdListFiles() by extending getFileExtension() function. Use shared isExtensionMatching() in place of isImageFileExtension(). Only allow executing .luac files when LUA_COMPILER defined (as per request).

* [simpgmspace] Fix f_mkdir() for MSVC build and misc. cleanup.

* [Lua] Use getFileExtension() in script loader to determine file type and check for buffer overflow.

radio/src/targets/simu/simpgmspace.cpp

@@ -24,10 +24,7 @@
 #include <stdarg.h>
 #include <sys/stat.h>
 
-#if defined(_MSC_VER)
-  #include <direct.h>
-  #define mkdir(s, f) _mkdir(s)
-#else
+#if !defined _MSC_VER
   #include <sys/time.h>
 #endif
 
@@ -522,21 +519,24 @@ uint16_t stackAvailable()
 }
 
 #if defined(SDCARD) && !defined(SKIP_FATFS_DECLARATION) && !defined(SIMU_DISKIO)
+#if defined(_MSC_VER) || !defined(__GNUC__)
+  #include <direct.h>
+  #include <stdlib.h>
+  #include <sys/utime.h>
+  #define mkdir(s, f) _mkdir(s)
+#else
+  #include <utime.h>
+#endif
+#include "ff.h"
+#include <map>
+#include <string>
+
 namespace simu {
 #include <dirent.h>
-#if !defined WIN32
+#if !defined(_MSC_VER)
   #include <libgen.h>
 #endif
 }
-#include "ff.h"
-
-#if defined WIN32 || !defined __GNUC__
-#include <direct.h>
-#include <stdlib.h>
-#endif
-
-#include <map>
-#include <string>
 
 #if defined(CPUARM)
 FATFS g_FATFS_Obj;
@@ -647,6 +647,11 @@ FRESULT f_stat (const TCHAR * name, FILINFO *fno)
     TRACE_SIMPGMSPACE("f_stat(%s) = OK", path);
     if (fno) {
       fno->fattrib = (tmp.st_mode & S_IFDIR) ? AM_DIR : 0;
+      // convert to FatFs fdate/ftime
+      struct tm *ltime = localtime(&tmp.st_mtime);
+      fno->fdate = ((ltime->tm_year - 80) << 9) | ((ltime->tm_mon + 1) << 5) | ltime->tm_mday;
+      fno->ftime = (ltime->tm_hour << 11) | (ltime->tm_min << 5) | (ltime->tm_sec / 2);
+      fno->fsize = (DWORD)tmp.st_size;
     }
     return FR_OK;
   }
@@ -808,7 +813,11 @@ FRESULT f_mkfs (const TCHAR* path, BYTE opt, DWORD au, void* work, UINT len)
 FRESULT f_mkdir (const TCHAR * name)
 {
   char * path = convertSimuPath(name);
+#if defined(WIN32) && defined(__GNUC__)
+  if (mkdir(path)) {
+#else
   if (mkdir(path, 0777)) {
+#endif
     TRACE_SIMPGMSPACE("mkdir(%s) = error %d (%s)", path, errno, strerror(errno));
     return FR_INVALID_NAME;
   }
@@ -846,6 +855,38 @@ FRESULT f_rename(const TCHAR *oldname, const TCHAR *newname)
   return FR_OK;
 }
 
+FRESULT f_utime(const TCHAR* path, const FILINFO* fno)
+{
+  if (fno == NULL)
+    return FR_INVALID_PARAMETER;
+
+  char *simpath = convertSimuPath(path);
+  char *realPath = findTrueFileName(simpath);
+  struct utimbuf newTimes;
+  struct tm ltime;
+
+  // convert from FatFs fdate/ftime
+  ltime.tm_year = ((fno->fdate >> 9) & 0x7F) + 80;
+  ltime.tm_mon = ((fno->fdate >> 5) & 0xF) - 1;
+  ltime.tm_mday = (fno->fdate & 0x1F);
+  ltime.tm_hour = ((fno->ftime >> 11) & 0x1F);
+  ltime.tm_min = ((fno->ftime >> 5) & 0x3F);
+  ltime.tm_sec = (fno->ftime & 0x1F) * 2;
+  ltime.tm_isdst = -1;  // force mktime() to check dst
+
+  newTimes.modtime = mktime(&ltime);
+  newTimes.actime = newTimes.modtime;
+
+  if (utime(realPath, &newTimes)) {
+    TRACE_SIMPGMSPACE("f_utime(%s) = error %d (%s)", simpath, errno, strerror(errno));
+    return FR_DENIED;
+  }
+  else {
+    TRACE_SIMPGMSPACE("f_utime(%s) set mtime = %s", simpath, ctime(&newTimes.modtime));
+    return FR_OK;
+  }
+}
+
 int f_putc (TCHAR c, FIL * fil)
 {
   if (fil && fil->obj.fs) fwrite(&c, 1, 1, (FILE*)fil->obj.fs);
@@ -873,27 +914,33 @@ int f_printf (FIL *fil, const TCHAR * format, ...)
 FRESULT f_getcwd (TCHAR *path, UINT sz_path)
 {
   char cwd[1024];
+  size_t sdlen = strlen(simuSdDirectory);
   if (!getcwd(cwd, 1024)) {
     TRACE_SIMPGMSPACE("f_getcwd() = getcwd() error %d (%s)", errno, strerror(errno));
     strcpy(path, ".");
     return FR_NO_PATH;
   }
+  size_t cwdlen = strlen(cwd);
 
-  if (strlen(cwd) < strlen(simuSdDirectory)) {
+  if (cwdlen < sdlen) {
     TRACE_SIMPGMSPACE("f_getcwd() = logic error strlen(cwd) < strlen(simuSdDirectory):  cwd: \"%s\",  simuSdDirectory: \"%s\"", cwd, simuSdDirectory);
     strcpy(path, ".");
     return FR_NO_PATH;
   }
 
-  if (sz_path < (strlen(cwd) - strlen(simuSdDirectory))) {
-    TRACE_SIMPGMSPACE("f_getcwd(): buffer too short");
+  if (sz_path < (cwdlen - sdlen)) {
+    //TRACE_SIMPGMSPACE("f_getcwd(): buffer too short");
     return FR_NOT_ENOUGH_CORE;
   }
 
   // remove simuSdDirectory from the cwd
-  strcpy(path, cwd + strlen(simuSdDirectory));
+#ifdef _MSC_VER
+  strcpy(path, cwd + sdlen + 2);  // account for drive name
+#else
+  strcpy(path, cwd + sdlen);
+#endif
 
-  if (strlen(path) == 0) {
+  if (path[0] == '\0') {
     strcpy(path, "/");    // fix for the root directory
   }