SD library question.

Projects Programming
1

Working on file commands and having problems with listing directories.

The first time to list any directory seems fine, if I go back to a directory after listing a different directory files & directory names will be missing.

#include <SD.h>
#include <lists.h>
#include <lilParser.h>

enum commands { noCommand, rm, ls, pwd, cd, mkdir, rmdir };

lilParser mParser;

char workingDir[40] = "/";
char cmdCursor[] = ">";

void setup(void) {

  Serial.begin(9600);
  while (!Serial);
  if (!SD.begin(4)) {
    Serial.println(F("SD Drive failed to boot."));
    Serial.println(F("Shutting down."));
    while(true);
  }
  mParser.addCmd(rm, "rm");
  mParser.addCmd(ls, "ls");
  mParser.addCmd(pwd, "pwd");
  mParser.addCmd(cd, "cd");
  mParser.addCmd(mkdir, "mkdir");
  mParser.addCmd(rmdir, "rmdir");
  Serial.print(cmdCursor);
}


bool removeFile(void) {

    char fileName[20];
    char filePath[40];
    File theFile;
    bool  success;

    success = false;
    if (mParser.numParams()) {
      mParser.getParam(fileName);
      strcpy(filePath,workingDir);
      strcat(filePath,fileName);
      if (SD.exists(filePath)) {
        theFile = SD.open(filePath);
        if (!theFile.isDirectory()) {
          theFile.close();
          success = SD.remove(filePath);
          if (!success) {
            Serial.println(F("Unknown file error."));
          }
        } else {
          theFile.close();
          Serial.print(fileName);Serial.println(F(" is not a file."));
        }
      } else {
        Serial.println(F("No such file name."));
      }
    } else {
      Serial.println(F("Missing file name."));
    }
    return success;
  }


void listDirectory(void) {

    File wd;
    File entry;
  
    wd = SD.open(workingDir);
    do {
      entry = wd.openNextFile();
      if (entry) {
        Serial.print(entry.name());
        if (entry.isDirectory()) {
          Serial.println("/");
        } else {
          Serial.print("\t"); Serial.println(entry.size(), DEC);
        }
      }
    } while (entry);
    wd.rewindDirectory();
    wd.close();
  }


bool changeDirectory() {

    File  testFile;
    bool  success;
    char  path[20];
    char  temp[40];
    byte  trace;
    
    success = false;
    if (mParser.numParams()) {
      mParser.getParam(path);
      if (!strcmp(path,"..")) {
        trace = strlen(workingDir)-2;
        if (trace>0) {
          while(workingDir[trace]!='/' && trace>0) {
            trace--;
          }
          workingDir[trace+1] = '\0';
        } else {
          Serial.println(F("Already at root."));
        }
      } else {
        strcpy(temp, workingDir);
        strcat(temp, path);
        if (SD.exists(temp)) {
          testFile = SD.open(temp);
          success = testFile.isDirectory();
          if (success) {
            strcpy(workingDir, temp);
          } else {
            Serial.println(F("Path must be directory names, not filenames."));
          }
        } else {
          Serial.println(F("No such directory."));
        }
      }
    } else {
      Serial.println(F("Missing directory name."));
    }
    return success;
  }


  bool makeDirectory(void) {
    Serial.println(F("Not yet implemented."));
  }

  bool removeDirectory(void) {
    Serial.println(F("Not yet implemented."));
  }


  void loop() {

    char      inChar;
    commands  command;

    if (Serial.available()) {
      inChar = Serial.read();
      Serial.print(inChar);
      command = mParser.addChar(inChar);
      switch ((int)command) {                       // Cheat: Allows -1 passed back as error.
        case noCommand : break;
        case rm : removeFile(); break;
        case ls : listDirectory(); break;
        case pwd : Serial.print(workingDir);Serial.println("|"); break;
        case cd : changeDirectory(); break;
        case mkdir : makeDirectory(); break;
        case rmdir : removeDirectory(); break;
        case -1 : Serial.println("???"); break;
      }
      if (command) Serial.print(cmdCursor);
    }
  }

If you want to see the rest of the librarys, the parser & lists, just say the word. And I'll add 'em.

Thanks.

-jim lee

2

Don't bother, I figured it out.

Thanks!

-jim lee

3 
    if (mParser.numParams()) {

Why would a function called numParams() return a boolean? If it doesn't, why do you treat it as though it does?

     if (!strcmp(path,"..")) {

strcmp() returns -n, 0, or +n, depending on the lexical order of the entries. It would be far more understandable to compare the value to 0.

Where do you rewind to the root directory?

4

Somewhere in my foggy memory I recall that a boolean defined as 0 or not 0. IE any number not 0 for true & 0 for false. I think I picked it up back when I learned c a long, long time ago. I've been using them in that way ever since.

if (mParser.numParams()) { <- if it returns 0 I'm treating it as false. At that point thats all I was looking for. Got any params at all?

if (!strcmp(path,"..")) { <- Again, I never really thought about it. I'd been doing the string checks like that since I learned c.

rewinding the root was 1/2 the problem. I'd assumed going out of scope would call the File's destructor and that would take care of closing it. But that does not seem to be the case. I had to explicitly close each and every one before it would work corretly.

I'm surprised you didn't catch my force casting the enum to an int to catch the -1 error flag when parsing. I plan on re-writing that bit.

-jim lee