/*

 *   Copyright (c) 2001, 2006 Michael J. Roberts

 *   

 *   This file is part of TADS 3.

 *   

 *   This module defines classes and constants related to the File

 *   intrinsic class.  In particular, this module defines the Exception

 *   subclasses thrown by File methods.  

 */

#include <tads.h>

#include <file.h>

/* ------------------------------------------------------------------------ */

/*

 *   File Exception classes.  All File exceptions derive from FileException,

 *   to allow for generic 'catch' clauses which catch any file-related

 *   error.  

 */

class FileException: Exception

    displayException() { "file error"; }

;

/*

 *   File not found - this is thrown when attempting to open a file for

 *   reading and the file doesn't exist or can't be opened (because the user

 *   doesn't have privileges to read the file, or the file is already being

 *   used by another user, for example).

 */

class FileNotFoundException: FileException

    displayException() { "file not found"; }

;

/*

 *   File creation error - this is thrown when attempting to open a file for

 *   writing and the file can't be created; this can happen because the disk

 *   or the directory is full, due to privilege failures, or due to sharing

 *   violations, among other reasons.  

 */

class FileCreationException: FileException

    displayException() { "cannot create file"; }

;

/*

 *   File cannot be opened - this is thrown when attempting to open a file

 *   for reading and writing but the file can't be opened.  This can happen

 *   for numerous reasons: sharing violations, privilege failures, lack of

 *   space on the disk or in the directory. 

 */

class FileOpenException: FileException

    displayException() { "cannot open file"; }

;

/*

 *   File synchronization exception.  This is thrown when an operation

 *   (such as a read or write) is attempted during normal execution on a

 *   file object that was originally opened during pre-initialization.  A

 *   file object created during pre-initialization can't be used to access

 *   the file during ordinary execution, since the state of the external

 *   file might have changed since the pre-init session ended.  In such

 *   cases, a new file object must be created instead.  

 */

class FileSyncException: FileException

    displayException() { "file synchronization error"; }

;

/*

 *   File closed - this is thrown when an operation is attempted on a file

 *   that has already been explicitly closed. 

 */

class FileClosedException: FileException

    displayException() { "operation attempted on closed file"; }

;

/*

 *   File I/O exception - this is thrown when a read or write operation on a

 *   file fails.  This can indicate, for example, that the device containing

 *   the file is full, or that a physical media error occurred.  

 */

class FileIOException: FileException

    displayException() { "file I/O error"; }

;

/*

 *   File mode error - this is thrown when an attempted operation is

 *   incompatible with the file's mode.  This is thrown under these

 *   conditions:

 *   

 *   - writing to a file opened for read-only access

 *.  - reading from a file opened for write-only access

 *.  - calling readFile or writeFile on a raw-mode file

 *.  - calling readBytes or writeBytes on a non-raw-mode file 

 */

class FileModeException: FileException

    displayException() { "invalid file mode"; }

;

/*

 *   File safety error - this is thrown when an attempted "open" operation

 *   is prohibited by the current file safety level set by the user. 

 */

class FileSafetyException: FileException

    displayException()

    {

        "file operation prohibited by user-specified file safety level";

    }

;

/* export the file exceptions for use by the intrinsic class */

export FileNotFoundException 'File.FileNotFoundException';

export FileCreationException 'File.FileCreationException';

export FileOpenException 'File.FileOpenException';

export FileIOException 'File.FileIOException';

export FileSyncException 'File.FileSyncException';

export FileClosedException 'File.FileClosedException';

export FileModeException 'File.FileModeException';

export FileSafetyException 'File.FileSafetyException';