Fix RAM losses when creating files

File::File used to allocate RAM what was not freed when destroying the File object.
Adding a dedicated destructor war not enough to fix. It would also need copy- and move-constructors.

Removed the File::FILE(const char* name) constructor.
Changed the File::File(void) constructor to not malloc() any RAM.

Unified and changed the SDClass::open() methods.
Removed the open method without mode parameter. Instead gave the method with a mode parameter a default mode.
Now open() has the complete control over memory allocation. When it is not able to open a file no memory in left allocated.

Advantage: A created File what was not opened or was not able to be opened has not to be closed anymore to avoid memory losses. Only a scsessfilly opened file has to be closed.

Author: AnHardt

src/SD.cpp

@@ -119,34 +119,43 @@ bool SDClass::rmdir(const char *filepath)
 /**
   * @brief  Open a file on the SD disk, if not existing it's created
   * @param  filename: File name
+  * @param  mode: the mode in which to open the file
   * @retval File object referring to the opened file
   */
-File SDClass::open(const char *filepath)
+File SDClass::open(const char *filepath, uint8_t mode /* = FA_READ */)
 {
-  File file = File(filepath);
+  File file = File();
 
-  if (f_open(file._fil, filepath, FA_READ) != FR_OK) {
-    f_opendir(&file._dir, filepath);
+  file._name = (char *)malloc(strlen(filepath) + 1);
+  if (file._name == NULL) {
+    Error_Handler();
   }
-  return file;
-}
+  sprintf(file._name, "%s", filepath);
 
-/**
-  * @brief  Open a file on the SD disk, if not existing it's created
-  * @param  filename: File name
-  * @param  mode: the mode in which to open the file
-  * @retval File object referring to the opened file
-  */
-File SDClass::open(const char *filepath, uint8_t mode)
-{
-  File file = File(filepath);
+  file._fil = (FIL *)malloc(sizeof(FIL));
+  if (file._fil == NULL) {
+    Error_Handler();
+  }
 
+#if _FATFS == 68300
+  file._fil->obj.fs = 0;
+  file._dir.obj.fs = 0;
+#else
+  file._fil->fs = 0;
+  file._dir.fs = 0;
+#endif
+  
   if ((mode == FILE_WRITE) && (!SD.exists(filepath))) {
     mode = mode | FA_CREATE_ALWAYS;
   }
 
   if (f_open(file._fil, filepath, mode) != FR_OK) {
-    f_opendir(&file._dir, filepath);
+    free(file._fil);
+    file._fil = NULL;
+    if (f_opendir(&file._dir, filepath) != FR_OK) {
+      free(file._name);
+      file._name = NULL;
+    }
   }
   return file;
 }
@@ -167,52 +176,13 @@ bool SDClass::remove(const char *filepath)
 
 File SDClass::openRoot(void)
 {
-  File file = File(_fatFs.getRoot());
-
-  if (f_opendir(&file._dir, _fatFs.getRoot()) != FR_OK) {
-#if _FATFS == 68300
-    file._dir.obj.fs = 0;
-#else
-    file._dir.fs = 0;
-#endif
-  }
-  return file;
+  return open(_fatFs.getRoot());
 }
 
 File::File()
 {
   _name = NULL;
-  _fil = (FIL *)malloc(sizeof(FIL));
-  if (_fil == NULL) {
-    Error_Handler();
-  }
-#if _FATFS == 68300
-  _fil->obj.fs = 0;
-  _dir.obj.fs = 0;
-#else
-  _fil->fs = 0;
-  _dir.fs = 0;
-#endif
-}
-
-File::File(const char *name)
-{
-  _name = (char *)malloc(strlen(name) + 1);
-  if (_name == NULL) {
-    Error_Handler();
-  }
-  sprintf(_name, "%s", name);
-  _fil = (FIL *)malloc(sizeof(FIL));
-  if (_fil == NULL) {
-    Error_Handler();
-  }
-#if _FATFS == 68300
-  _fil->obj.fs = 0;
-  _dir.obj.fs = 0;
-#else
-  _fil->fs = 0;
-  _dir.fs = 0;
-#endif
+  _fil = NULL;
 }
 
 /** List directory contents to Serial.
@@ -617,9 +587,6 @@ File File::openNextFile(uint8_t mode)
   FRESULT res = FR_OK;
   FILINFO fno;
   char *fn;
-  char *fullPath = NULL;
-  size_t name_len = strlen(_name);
-  size_t len = name_len;
 #if _USE_LFN && _FATFS != 68300
   static char lfn[_MAX_LFN];
   fno.lfname = lfn;
@@ -638,8 +605,8 @@ File File::openNextFile(uint8_t mode)
 #else
     fn = fno.fname;
 #endif
-    len += strlen(fn) + 2;
-    fullPath = (char *)malloc(len);
+    size_t name_len = strlen(_name);
+    char *fullPath = (char *)malloc(name_len + strlen(fn) + 2);
     if (fullPath != NULL) {
       // Avoid twice '/'
       if ((name_len > 0)  && (_name[name_len - 1] == '/')) {

src/STM32SD.h

@@ -33,7 +33,6 @@ uint8_t const LS_R = 4;
 class File {
   public:
     File(void);
-    File(const char *name);
     virtual size_t write(uint8_t);
     virtual size_t write(const uint8_t *buf, size_t size);
     virtual size_t write(const char *buf, size_t size);
@@ -82,8 +81,7 @@ class SDClass {
 
     /* Initialize the SD peripheral */
     bool begin(uint32_t detectpin = SD_DETECT_NONE);
-    static File open(const char *filepath, uint8_t mode);
-    static File open(const char *filepath);
+    static File open(const char *filepath, uint8_t mode = FA_READ);
     static bool exists(const char *filepath);
     static bool mkdir(const char *filepath);
     static bool remove(const char *filepath);