Espruino/libs/filesystem/jswrap_file.c

/*
 * This file is part of Espruino, a JavaScript interpreter for Microcontrollers
 *
 * Copyright (C) 2013 Gordon Williams <gw@pur3.co.uk>
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * ----------------------------------------------------------------------------
 * This file is designed to be parsed during the build process
 *
 * Contains built-in functions for SD card access
 * ----------------------------------------------------------------------------
 */
#include "jswrap_file.h"

#define JS_FS_DATA_NAME JS_HIDDEN_CHAR_STR"FSdata" // the data in each file
#define JS_FS_OPEN_FILES_NAME JS_HIDDEN_CHAR_STR"FSOpenFiles" // the list of open files


#ifndef LINUX
FATFS jsfsFAT;
#endif

bool fat_initialised = false;

void jsfsReportError(const char *msg, FRESULT res) {
  const char *errStr = "UNKNOWN";
  if (res==FR_OK             ) errStr = "OK";
#ifndef LINUX
  else if (res==FR_DISK_ERR       ) errStr = "DISK_ERR";
  else if (res==FR_INT_ERR        ) errStr = "INT_ERR";
  else if (res==FR_NOT_READY      ) errStr = "NOT_READY";
  else if (res==FR_NO_FILE        ) errStr = "NO_FILE";
  else if (res==FR_NO_PATH        ) errStr = "NO_PATH";
  else if (res==FR_INVALID_NAME   ) errStr = "INVALID_NAME";
  else if (res==FR_DENIED         ) errStr = "DENIED";
  else if (res==FR_EXIST          ) errStr = "EXIST";
  else if (res==FR_INVALID_OBJECT ) errStr = "INVALID_OBJECT";
  else if (res==FR_WRITE_PROTECTED) errStr = "WRITE_PROTECTED";
  else if (res==FR_INVALID_DRIVE  ) errStr = "INVALID_DRIVE";
  else if (res==FR_NOT_ENABLED    ) errStr = "NOT_ENABLED";
  else if (res==FR_NO_FILESYSTEM  ) errStr = "NO_FILESYSTEM";
  else if (res==FR_MKFS_ABORTED   ) errStr = "MKFS_ABORTED";
  else if (res==FR_TIMEOUT        ) errStr = "TIMEOUT";
#endif
  jsError("%s : %s", msg, errStr);
}

bool jsfsInit() {
#ifndef LINUX
  if (!fat_initialised) {
    FRESULT res;
    if ((res = f_mount(&jsfsFAT, "", 1/*immediate*/)) != FR_OK) {
      jsfsReportError("Unable to mount SD card", res);
      return false;
    }
    fat_initialised = true;
  }
#endif
  return true;
}





/* TODO: maybe this should be in the 'E' library. However we don't currently
 * have a way of doing that in build_jswrapper.py  */
/*JSON{
  "type" : "class",
  "class" : "File"
}
This is the File object - it allows you to stream data to and from files (As opposed to the `require('fs').readFile(..)` style functions that read an entire file).

To create a File object, you must type ```var fd = E.openFile('filepath','mode')``` - see [E.openFile](#l_E_openFile) for more information.

**Note:** If you want to remove an SD card after you have started using it, you *must* call `E.unmountSD()` or you may cause damage to the card.
*/

static JsVar* fsGetArray(bool create) {
  return jsvObjectGetChild(execInfo.hiddenRoot, JS_FS_OPEN_FILES_NAME, create ? JSV_ARRAY : 0);
}

static bool fileGetFromVar(JsFile *file, JsVar *parent) {
  bool ret = false;
  JsVar *fHandle = jsvObjectGetChild(parent, JS_FS_DATA_NAME, 0);
  if (fHandle) {
    jsvGetString(fHandle, (char*)&file->data, sizeof(JsFileData)+1/*trailing zero*/);
    jsvUnLock(fHandle);
    file->fileVar = parent;
    if(file->data.state == FS_OPEN) {// return false if the file has been closed.
      ret = true;
    }
  }
  return ret;
}

static void fileSetVar(JsFile *file) {
  JsVar *fHandle = jsvFindChildFromString(file->fileVar, JS_FS_DATA_NAME, true);
  JsVar *data = jsvSkipName(fHandle);
  if (!data) {
    data = jsvNewStringOfLength(sizeof(JsFileData));
    jsvSetValueOfName(fHandle, data);
  }
  jsvUnLock(fHandle);
  assert(data);
  jsvSetString(data, (char*)&file->data, sizeof(JsFileData));
  jsvUnLock(data);
}

/*JSON{
  "type" : "kill",
  "generate" : "jswrap_file_kill"
}*/
void jswrap_file_kill() {
  JsVar *arr = fsGetArray(false);
  if (arr) {
    JsvObjectIterator it;
    jsvObjectIteratorNew(&it, arr);
    while (jsvObjectIteratorHasValue(&it)) {
      JsVar *file = jsvObjectIteratorGetValue(&it);
      jswrap_file_close(file);
      jsvUnLock(file);
      jsvObjectIteratorNext(&it);
    }
    jsvObjectIteratorFree(&it);
    jsvRemoveAllChildren(arr);
    jsvUnLock(arr);
  }
  // close fs library
#ifndef LINUX
  if (fat_initialised) {
    fat_initialised = false;
    f_mount(0, 0, 0);
  }
#endif
}

/*JSON{
  "type" : "staticmethod",
  "class" : "E",
  "name" : "unmountSD",
  "generate" : "jswrap_E_unmountSD"
}
Unmount the SD card, so it can be removed. If you remove the SD card without calling this you may cause corruption, and you will be unable to access another SD card until you reset Espruino or call `E.unmountSD()`.
*/
void jswrap_E_unmountSD() {
  jswrap_file_kill();
}

static bool allocateJsFile(JsFile* file,FileMode mode, FileType type) {
  JsVar *parent = jspNewObject(0, "File");
  if (!parent) return false; // low memory
  file->fileVar = parent;
  file->data.mode = mode;
  file->data.type = type;
  file->data.state = FS_NONE;
  return true;
}

/*JSON{
  "type" : "staticmethod",
  "class" : "E",
  "name" : "openFile",
  "generate" : "jswrap_E_openFile",
  "params" : [
    ["path","JsVar","the path to the file to open."],
    ["mode","JsVar","The mode to use when opening the file. Valid values for mode are 'r' for read, 'w' for write new, 'w+' for write existing, and 'a' for append. If not specified, the default is 'r'."]
  ],
  "return" : ["JsVar","A File object"],
  "return_object" : "File"
}
Open a file
*/
JsVar *jswrap_E_openFile(JsVar* path, JsVar* mode) {
  FRESULT res = FR_INVALID_NAME;
  JsFile file;
  file.fileVar = 0;
  FileMode fMode = FM_NONE;
  if (jsfsInit()) {
    JsVar *arr = fsGetArray(true);
    if (!arr) return 0; // out of memory

    char pathStr[JS_DIR_BUF_SIZE] = "";
    char modeStr[3] = "r";
    if (!jsvIsUndefined(path)) {
      jsvGetString(path, pathStr, JS_DIR_BUF_SIZE);
      if (!jsvIsUndefined(mode))
        jsvGetString(mode, modeStr, 3);

#ifndef LINUX
      BYTE ff_mode = 0;
      bool append = false;
#endif

      if(strcmp(modeStr,"r") == 0) {
        fMode = FM_READ;
#ifndef LINUX
        ff_mode = FA_READ | FA_OPEN_EXISTING;
#endif
      } else if(strcmp(modeStr,"a") == 0) {
        fMode = FM_WRITE;
#ifndef LINUX
        ff_mode = FA_WRITE | FA_OPEN_ALWAYS;
        append = true;
#endif
      } else if(strcmp(modeStr,"w") == 0) {
        fMode = FM_WRITE;
#ifndef LINUX
        ff_mode = FA_WRITE | FA_CREATE_ALWAYS;
#endif
      } else if(strcmp(modeStr,"w+") == 0) {
        fMode = FM_READ_WRITE;
#ifndef LINUX
        ff_mode = FA_WRITE | FA_OPEN_ALWAYS;
#endif
      }
      if(fMode != FM_NONE && allocateJsFile(&file, fMode, FT_FILE)) {
#ifndef LINUX
        if ((res=f_open(&file.data.handle, pathStr, ff_mode)) == FR_OK) {
          if (append) f_lseek(&file.data.handle, file.data.handle.fsize); // move to end of file
#else
        file.data.handle = fopen(pathStr, modeStr);
        if (file.data.handle) {
          res=FR_OK;
#endif
          file.data.state = FS_OPEN;
          fileSetVar(&file);
          // add to list of open files
          jsvArrayPush(arr, file.fileVar);
        } else {
          // File open failed
          jsvUnLock(file.fileVar);
          file.fileVar = 0;
        }

        if(res != FR_OK)
          jsfsReportError("Could not open file", res);

      }
    } else {
      jsError("Path is undefined");
    }

    jsvUnLock(arr);
  }


  return file.fileVar;
}

/*JSON{
  "type" : "method",
  "class" : "File",
  "name" : "close",
  "generate_full" : "jswrap_file_close(parent)"
}
Close an open file.
*/
void jswrap_file_close(JsVar* parent) {
  if (jsfsInit()) {
    JsFile file;
    if (fileGetFromVar(&file, parent) && file.data.state == FS_OPEN) {
#ifndef LINUX
      f_close(&file.data.handle);
#else
      fclose(file.data.handle);
      file.data.handle = 0;
#endif
      file.data.state = FS_CLOSED;
      fileSetVar(&file);
      // TODO: could try and free the memory used by file.data ?

      JsVar *arr = fsGetArray(false);
      if (arr) {
        JsVar *idx = jsvGetArrayIndexOf(arr, file.fileVar, true);
        if (idx) {
          jsvRemoveChild(arr, idx);
          jsvUnLock(idx);
        }
        jsvUnLock(arr);
      }
    }
  }
}

/*JSON{
  "type" : "method",
  "class" : "File",
  "name" : "write",
  "generate" : "jswrap_file_write",
  "params" : [
    ["buffer","JsVar","A string containing the bytes to write"]
  ],
  "return" : ["int32","the number of bytes written"]
}
write data to a file
*/
size_t jswrap_file_write(JsVar* parent, JsVar* buffer) {
  FRESULT res = 0;
  size_t bytesWritten = 0;
  if (jsfsInit()) {
    JsFile file;
    if (fileGetFromVar(&file, parent)) {
      if(file.data.mode == FM_WRITE || file.data.mode == FM_READ_WRITE) {
        JsvIterator it;
        jsvIteratorNew(&it, buffer);
        char buf[32];

        while (jsvIteratorHasElement(&it)) {
          // pull in a buffer's worth of data
          size_t n = 0;
          while (jsvIteratorHasElement(&it) && n<sizeof(buf)) {
            buf[n++] = (char)jsvIteratorGetIntegerValue(&it);
            jsvIteratorNext(&it);
          }
          // write it out
          size_t written = 0;
#ifndef LINUX
          res = f_write(&file.data.handle, &buf, n, &written);
#else
          written = fwrite(&buf, 1, n, file.data.handle);
#endif
          bytesWritten += written;
          if(written == 0)
            res = FR_DISK_ERR;
          if (res) break;
        }
        jsvIteratorFree(&it);
        // finally, sync - just in case there's a reset or something
#ifndef LINUX
        f_sync(&file.data.handle);
#else
        fflush(file.data.handle);
#endif
      }

      fileSetVar(&file);
    }
  }

  if (res) {
    jsfsReportError("Unable to write file", res);
  }
  return bytesWritten;
}

/*JSON{
  "type" : "method",
  "class" : "File",
  "name" : "read",
  "generate" : "jswrap_file_read",
  "params" : [
    ["length","int32","is an integer specifying the number of bytes to read."]
  ],
  "return" : ["JsVar","A string containing the characters that were read"]
}
Read data in a file in byte size chunks
*/
JsVar *jswrap_file_read(JsVar* parent, int length) {
  JsVar *buffer = 0;
  JsvStringIterator it;
  FRESULT res = 0;
  size_t bytesRead = 0;
  if (jsfsInit()) {
    JsFile file;
    if (fileGetFromVar(&file, parent)) {
      if(file.data.mode == FM_READ || file.data.mode == FM_READ_WRITE) {
        char buf[32];
        size_t actual = 0;

        while (bytesRead < (size_t)length) {
          size_t requested = (size_t)length - bytesRead;
          if (requested > sizeof( buf ))
            requested = sizeof( buf );
          actual = 0;
    #ifndef LINUX
          res = f_read(&file.data.handle, buf, requested, &actual);
          if(res) break;
    #else
          actual = fread(buf, 1, requested, file.data.handle);
    #endif
          if (actual>0) {
            if (!buffer) {
              buffer = jsvNewFromEmptyString();
              if (!buffer) return 0; // out of memory
              jsvStringIteratorNew(&it, buffer, 0);
            }
            size_t i;
            for (i=0;i<actual;i++)
              jsvStringIteratorAppend(&it, buf[i]);
          }
          bytesRead += actual;
          if(actual != requested) break;
        }
        fileSetVar(&file);
      }
    }
  }
  if (res) jsfsReportError("Unable to read file", res);

  if (buffer)
    jsvStringIteratorFree(&it);

  return buffer;
}

/*JSON{
  "type" : "method",
  "class" : "File",
  "name" : "skip",
  "generate_full" : "jswrap_file_skip_or_seek(parent,nBytes,true)",
  "params" : [
    ["nBytes","int32","is a positive integer specifying the number of bytes to skip forwards."]
  ]
}
Skip the specified number of bytes forward in the file
*/
/*JSON{
  "type" : "method",
  "class" : "File",
  "name" : "seek",
  "generate_full" : "jswrap_file_skip_or_seek(parent,nBytes,false)",
  "params" : [
    ["nBytes","int32","is an integer specifying the number of bytes to skip forwards."]
  ]
}
Seek to a certain position in the file
*/
void jswrap_file_skip_or_seek(JsVar* parent, int nBytes, bool is_skip) {
  if (nBytes<0) {
    jsWarn(is_skip ? "Bytes to skip must be >=0" : "Position to seek to must be >=0");
    return;
  }
  FRESULT res = 0;
  if (jsfsInit()) {
    JsFile file;
    if (fileGetFromVar(&file, parent)) {
      if(file.data.mode == FM_READ || file.data.mode == FM_WRITE || file.data.mode == FM_READ_WRITE) {
  #ifndef LINUX
        res = (FRESULT)f_lseek(&file.data.handle, (DWORD)(is_skip ? f_tell(&file.data.handle) : 0) + (DWORD)nBytes);
  #else
        fseek(file.data.handle, nBytes, is_skip ? SEEK_CUR : SEEK_SET);
  #endif
        fileSetVar(&file);
      }
    }
  }
  if (res) jsfsReportError(is_skip?"Unable to skip":"Unable to seek", res);
}

/*JSON{
  "type" : "method",
  "class" : "File",
  "name" : "pipe",
  "ifndef" : "SAVE_ON_FLASH",
  "generate" : "jswrap_pipe",
  "params" : [
    ["destination","JsVar","The destination file/stream that will receive content from the source."],
    ["options","JsVar",["An optional object `{ chunkSize : int=32, end : bool=true, complete : function }`","chunkSize : The amount of data to pipe from source to destination at a time","complete : a function to call when the pipe activity is complete","end : call the 'end' function on the destination when the source is finished"]]
  ]
}
Pipe this file to a stream (an object with a 'write' method)
*/