filehandle.pmc

/*
Copyright (C) 2008-2011, Parrot Foundation.

=head1 NAME

src/pmc/filehandle.pmc - FileHandle PMC

=head1 DESCRIPTION

The FileHandle PMC performs I/O operations on a source or destination file.

=head2 Vtable Functions

=over 4

=cut

*/

#include "../src/io/io_private.h"
#include "pmc/pmc_bytebuffer.h"

#ifdef PARROT_HAS_READLINE
#ifdef __cplusplus
extern "C" {
#endif
    char *readline(const char *);
    void add_history(const char*);
#ifdef __cplusplus
}
#endif
#endif

/* HEADERIZER HFILE: none */
/* HEADERIZER BEGIN: static */
/* HEADERIZER END: static */

pmclass FileHandle extends Handle auto_attrs {
    ATTR INTVAL flags;                /* Filehandle flags             */
    ATTR STRING *filename;            /* The opened path and filename */
    ATTR STRING *mode;                /* The mode string used in open */
    ATTR STRING *encoding;            /* The encoding for read/write  */
    ATTR INTVAL process_id;           /* Child process on pipes       */
    ATTR INTVAL exit_status;          /* Child exit status on pipes   */
    ATTR PIOOFF_T file_pos;           /* Current real file pointer    */
    ATTR PIOOFF_T last_pos;           /* Last file position           */
    ATTR size_t buffer_size;          /* Buffer size                  */
    ATTR INTVAL buffer_flags;         /* Buffer flags                 */
    ATTR unsigned char *buffer_start; /* Start of buffer              */
    ATTR unsigned char *buffer_end;   /* End of buffer                */
    ATTR unsigned char *buffer_next;  /* Current read/write pointer   */

/*
 * Using INTVAL for process_id is a temporary solution.
 * We may need to define a custom type to store it in a platform dependant way.
 */

/*

=item C<void init()>

Initializes a newly created FileHandle object.

=cut

*/

    VTABLE void init() {
        Parrot_FileHandle_attributes * const attrs =
            PMC_data_typed(SELF, Parrot_FileHandle_attributes *);

        attrs->record_separator = '\n';
        attrs->flags            = 0;
        attrs->filename         = STRINGNULL;
        attrs->mode             = STRINGNULL;
        attrs->encoding         = STRINGNULL;
        attrs->process_id       = 0;
        attrs->exit_status      = 0;
        attrs->file_pos         = piooffsetzero;
        attrs->last_pos         = piooffsetzero;
        attrs->buffer_size      = 0;
        attrs->buffer_flags     = 0;
        attrs->buffer_start     = NULL;
        attrs->buffer_end       = NULL;
        attrs->buffer_next      = NULL;

        /* Initialize the os_handle to the platform-specific value for closed */
        attrs->os_handle     = (PIOHANDLE) PIO_INVALID_HANDLE;

        PObj_custom_mark_SET(SELF);
        PObj_custom_destroy_SET(SELF);
    }


/*

=item C<PMC *clone()>

Create a copy of the filehandle.

=cut

*/

    VTABLE PMC *clone() {
        Parrot_FileHandle_attributes * const old_attrs
            = PARROT_FILEHANDLE(SELF);
        PMC * const copy = Parrot_pmc_new(interp, enum_class_FileHandle);
        Parrot_FileHandle_attributes * const new_attrs
            = PARROT_FILEHANDLE(copy);

        /* Properly clone string data. */
        new_attrs->filename       = old_attrs->filename;
        new_attrs->mode           = old_attrs->mode;
        new_attrs->encoding       = old_attrs->encoding;

        /* Prevent GC of the strings. */
        Parrot_gc_mark_STRING_alive(INTERP, new_attrs->filename);
        Parrot_gc_mark_STRING_alive(INTERP, new_attrs->mode);
        Parrot_gc_mark_STRING_alive(INTERP, new_attrs->encoding);

        /* Copy over some metadata */
        new_attrs->flags          = old_attrs->flags;
        new_attrs->process_id     = old_attrs->process_id;
        new_attrs->exit_status    = old_attrs->exit_status;
        new_attrs->file_pos       = old_attrs->file_pos;
        new_attrs->last_pos       = old_attrs->last_pos;

        /* Duplicate the file handle. */
        new_attrs->os_handle = PIO_DUP(interp, old_attrs->os_handle);

        /* We need to correctly allocate a buffer, so we check for the buffering mode. */
        if (new_attrs->flags & PIO_F_LINEBUF)
            Parrot_io_setbuf(INTERP, copy, PIO_LINEBUFSIZE);
        else
            Parrot_io_setbuf(INTERP, copy, old_attrs->buffer_size);

        /* Transfer only read/write flags on the buffer. */
        new_attrs->buffer_flags &= ~(PIO_BF_READBUF & PIO_BF_WRITEBUF);
        new_attrs->buffer_flags |= old_attrs->buffer_flags &
            (PIO_BF_READBUF & PIO_BF_WRITEBUF);

        /* Then after we've set the buffer mode we can memcpy the data over. */
        if (old_attrs->buffer_size > 0)
            memcpy(new_attrs->buffer_start, old_attrs->buffer_start,
                old_attrs->buffer_end - old_attrs->buffer_start);

        /* This is an offset, so we must do math to get a new offset. */
        new_attrs->buffer_next = new_attrs->buffer_start +
            (old_attrs->buffer_next - old_attrs->buffer_start);

        return copy;
    }


/*

=item C<void mark()>

Mark active filehandle data as live.

=cut

*/

    VTABLE void mark() {
        Parrot_FileHandle_attributes * const attrs
            = PARROT_FILEHANDLE(SELF);

        Parrot_gc_mark_STRING_alive(INTERP, attrs->mode);
        Parrot_gc_mark_STRING_alive(INTERP, attrs->filename);
        Parrot_gc_mark_STRING_alive(INTERP, attrs->encoding);
    }


/*

=item C<void destroy()>

Free structures.

=cut

*/
    VTABLE void destroy() {
        if (PARROT_FILEHANDLE(SELF)) {
            Parrot_FileHandle_attributes * const attrs = PARROT_FILEHANDLE(SELF);

            if (!Parrot_io_is_closed_filehandle(INTERP, SELF)) {
                if (attrs->flags & PIO_F_SHARED)
                    Parrot_io_flush_filehandle(INTERP, SELF);
                else
                    Parrot_io_close_filehandle(INTERP, SELF);
            }

            if (attrs->buffer_start)
                mem_gc_free(INTERP, attrs->buffer_start);
        }
    }


/*

=item C<INTVAL get_integer_keyed_int(INTVAL key)>

Shortcut to get the value of some attributes.
For internal usage only, subject to change without notice.

=cut

*/

    VTABLE INTVAL get_integer_keyed_int(INTVAL key) {
        INTVAL result;
        switch (key) {
          case 0:
            GET_ATTR_process_id(INTERP, SELF, result);
            break;
          default:
            result = 0;
        }

        return result;
    }


/*

=item C<void set_integer_keyed_int(INTVAL key, INTVAL value)>

Shortcut to set the value of some attributes
For internal usage only, subject to change without notice.

=cut

*/

    VTABLE void set_integer_keyed_int(INTVAL key, INTVAL value) {
        switch (key) {
          case 0:
            SET_ATTR_process_id(INTERP, SELF, value);
            break;
          default:
            break;
        }
    }


/*

=item C<INTVAL get_bool()>

Return false if a previous read attempted to read past the end of the underlying
filehandle.  Note that this method may return true even if there are no bytes
remaining if the most recent read requested the exact number of bytes remaining
in the file.


=cut

*/

    VTABLE INTVAL get_bool() {
        return !Parrot_io_eof(INTERP, SELF);
    }


/*

=back

=head2 Methods

=over 4

=item C<METHOD open(STRING *filename :optional, STRING *mode :optional)>

Opens the file at the given filename (including path) with the given mode. The
invocant is modified and becomes an open filehandle. A copy of the invocant is
also returned by the method (some subclasses may create this as the primary
filehandle, rather than modifying the invocant).

=cut

*/

    METHOD open(STRING *filename :optional, INTVAL got_filename :opt_flag,
        STRING *mode :optional, INTVAL got_mode :opt_flag) {
        PMC    *filehandle;

        if (!Parrot_io_is_closed_filehandle(INTERP, SELF))
            Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_PIO_ERROR,
                                "Cannot reopen already open filehandle");

        if (!got_mode || STRING_IS_NULL(mode))
            GET_ATTR_mode(INTERP, SELF, mode);

        if (!got_filename || STRING_IS_NULL(filename))
            GET_ATTR_filename(INTERP, SELF, filename);

        filehandle = Parrot_io_open_handle(INTERP, SELF, filename, mode);

        RETURN(PMC *filehandle);
    }


/*

=item C<METHOD read_bytes(INTVAL bytes)>

Read the given number of bytes from the handle and return them in a
ByteBuffer.

=cut

*/

    METHOD read_bytes(INTVAL length) {
        PMC           *buffer;
        unsigned char *content;
        INTVAL         bytes_read;
        INTVAL         flags;

        GETATTR_FileHandle_flags(INTERP, SELF, flags);

        if (Parrot_io_is_closed_filehandle(INTERP, SELF)
        || !(flags & PIO_F_READ))
            Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_PIO_ERROR,
                "Cannot read from a closed or non-readable filehandle");

        buffer = Parrot_pmc_new_init_int(INTERP, enum_class_ByteBuffer, length);
        GETATTR_ByteBuffer_content(INTERP, buffer, content);

        bytes_read = Parrot_io_read_buffer(INTERP, SELF, (char *)content, length);

        if (bytes_read != length)
            VTABLE_set_integer_native(INTERP, buffer, bytes_read);

        RETURN(PMC *buffer);
    }


/*

=item C<METHOD isatty()>

Returns a boolean value indicating whether C<SELF> is a console/tty.

=cut

*/

    METHOD isatty() {
        const INTVAL isatty = Parrot_io_is_tty_handle(INTERP, SELF);
        RETURN(INTVAL isatty);
    }


/*

=item C<METHOD is_closed()>

Test if the filehandle is closed.

=cut

*/

    METHOD is_closed() {
        const INTVAL status = Parrot_io_is_closed(INTERP, SELF);
        RETURN(INTVAL status);
    }


/*

=item C<METHOD readline_interactive(STRING *prompt)>

Read a line from the filehandle and return it in a string.

=cut

*/

    METHOD readline_interactive(STRING *prompt     :optional,
                                INTVAL  got_prompt :opt_flag) {
        STRING *string_result = NULL;

#ifdef PARROT_HAS_READLINE
    /* 4-column indent to get c_indent.t to DTRT */
        char * const prompt_cstring =
            (got_prompt ? Parrot_str_to_cstring(INTERP, prompt) : NULL);
        char * const r = readline(prompt_cstring);
        Parrot_str_free_cstring(prompt_cstring);

        if (r) {
            STRING *encoding;
            const STR_VTABLE *enc = NULL;
            GET_ATTR_encoding(INTERP, SELF, encoding);
            if (*r)
                add_history(r);
            if (!STRING_IS_NULL(encoding))
                enc = Parrot_find_encoding_by_string(INTERP, encoding);
            if (enc == NULL)
                string_result = Parrot_str_new(INTERP, r, 0);
            else
                string_result = Parrot_str_new_init(INTERP, r, strlen(r), enc, 0);
            free(r);
        }
#else
        if (got_prompt) {
            char * const prompt_cstring = Parrot_str_to_cstring(INTERP, prompt);
            fprintf(stderr, "%s", prompt_cstring);
            Parrot_str_free_cstring(prompt_cstring);
        }

        string_result = Parrot_io_readline(INTERP, SELF);

        {
            INTVAL len = STRING_length(string_result);

            if (len == 0) {
                string_result = NULL;
            }
            else {
                while (len > 0) {
                    const INTVAL c = STRING_ord(interp, string_result, len - 1);

                    if (c != '\n' && c != '\r')
                        break;

                    --len;
                }

                string_result = STRING_substr(interp, string_result, 0, len);
            }
        }
#endif

        if (string_result)
            RETURN(STRING *string_result);
        else
            RETURN(PMC *PMCNULL);
    }

/*

=item METHOD readall(STRING *name);

Read the entire contents of a file named I<name> into a Parrot string. On a
filehandle object that isn't opened yet, the path to a file can be passed to
C<readall> and it will open a filehandle on that file, read in the contents,
and close the filehandle.

  .local pmc pio
  pio = new 'FileHandle'
  $S0 = pio.'readall'('the_file')

If the filehandle is already open, then no file path should be passed. The
C<readall> method will read the contents of the file, and will not close the
filehandle when finished.

  pio = open 'the_file', 'r'
  $S0 = pio.'readall'()

=cut

*/

    METHOD readall(STRING *name :optional, INTVAL got_name :opt_flag) {
        STRING *result;

        if (got_name) {
            /* called as class method - open, slurp, close file */
            PMC    *filehandle;
            STRING *encoding;
            size_t  size;

            GET_ATTR_encoding(INTERP, SELF, encoding);

            if (!Parrot_io_is_closed_filehandle(INTERP, SELF))
                Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_PIO_ERROR,
                    "Cannot readall on a new file from an already open filehandle");

            filehandle  = Parrot_io_open_handle(INTERP, PMCNULL, name, STRINGNULL);

            PARROT_ASSERT(filehandle->vtable->base_type == enum_class_FileHandle);

            SET_ATTR_encoding(INTERP, filehandle, encoding);
            size = (size_t)(Parrot_file_stat_intval(INTERP, name, STAT_FILESIZE));

            result = Parrot_io_reads(INTERP, filehandle, size);
            Parrot_io_close_handle(INTERP, filehandle);
        }
        else {
            PMC *sb;

            /* slurp open file */
            if (Parrot_io_is_closed_filehandle(INTERP, SELF))
                Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_PIO_ERROR,
                    "Cannot readall without a file name or open filehandle");

            sb = Parrot_pmc_new_init_int(interp, enum_class_StringBuilder,
                    4096);

            do {
                STRING * const part = Parrot_io_reads(INTERP, SELF, 4096);
                VTABLE_push_string(interp, sb, part);
            } while (!Parrot_io_eof(INTERP, SELF));

            result = VTABLE_get_string(interp, sb);
        }

        RETURN(STRING *result);
    }


/*

=item C<METHOD flush()>

Flushes the filehandle.

=cut

*/

    METHOD flush() {
        Parrot_io_flush_filehandle(INTERP, SELF);
    }

/*

=item C<METHOD print([INTVAL|FLOATVAL|STRING *|PMC*] value)>

Print the passed in integer, number, string, or PMC to the filehandle.
(Integers, numbers, and strings are auto-boxed as PMCs.)

=cut

*/

    METHOD print(PMC *to_print) {
        STRING * const string_to_print = VTABLE_get_string(INTERP, to_print);

        const INTVAL status = Parrot_io_putps(INTERP, SELF, string_to_print);

        RETURN(INTVAL status);
    }

/*

=item C<METHOD buffer_type(STRING *new_type :optional)>

Set or retrieve the buffering behavior for the filehandle. The argument and
return value are one of the following:

=over

=item C<unbuffered>

Buffering disabled, bytes are sent as soon as possible.

=item C<line-buffered>

Line buffering, bytes are sent when a record separator is encountered.

=item C<full-buffered>

Full buffering, bytes are sent when the buffer is full.

=cut

*/

    METHOD buffer_type(STRING *new_type :optional, INTVAL got_type :opt_flag) {
        STRING * const nobuffer_string   = CONST_STRING(INTERP, "unbuffered");
        STRING * const linebuffer_string = CONST_STRING(INTERP, "line-buffered");
        STRING * const fullbuffer_string = CONST_STRING(INTERP, "full-buffered");
        INTVAL flags;

        if (got_type) {
            if (STRING_equal(INTERP, new_type, nobuffer_string))
                Parrot_io_setbuf(INTERP, SELF, PIOCTL_NONBUF);
            else if (STRING_equal(INTERP, new_type, linebuffer_string))
                Parrot_io_setlinebuf(INTERP, SELF);
            else if (STRING_equal(INTERP, new_type, fullbuffer_string))
                Parrot_io_setbuf(INTERP, SELF, PIO_UNBOUND);
        }

        GET_ATTR_flags(INTERP, SELF, flags);

        if (flags & PIO_F_LINEBUF)
            RETURN(STRING *linebuffer_string);
        else if (flags & PIO_F_BLKBUF)
            RETURN(STRING *fullbuffer_string);

        RETURN(STRING *nobuffer_string);
    }


/*

=item C<METHOD buffer_size(INTVAL new_size :optional)>

Set or retrieve the buffer size for the filehandle.

=cut

*/

    METHOD buffer_size(INTVAL new_size :optional, INTVAL got_size :opt_flag) {
        INTVAL buffer_size;

        if (got_size)
            Parrot_io_setbuf(INTERP, SELF, (size_t)new_size);

        buffer_size = (INTVAL)Parrot_io_get_buffer_size(INTERP, SELF);

        RETURN(INTVAL buffer_size);
    }


/*

=item C<METHOD mode()>

Retrieve the read mode string for the filehandle.

=cut

*/

    METHOD mode() {
        STRING *mode;
        GET_ATTR_mode(INTERP, SELF, mode);
        RETURN(STRING *mode);
    }


/*

=item C<METHOD encoding(STRING *new_encoding)>

Set or retrieve the encoding attribute (a string name of the selected encoding
scheme) for the filehandle.

=cut

*/

    METHOD encoding(STRING *new_encoding :optional, INTVAL got_encoding :opt_flag) {
        STRING *encoding;

        if (got_encoding) {
            SET_ATTR_encoding(INTERP, SELF, new_encoding);
            RETURN(STRING *new_encoding);
        }

        GET_ATTR_encoding(INTERP, SELF, encoding);
        RETURN(STRING *encoding);
    }


/*

=item C<METHOD eof()>

Return true if a previous read attempted to read past the end of the underlying
filehandle.  Note that this method may return false even if there are no bytes
remaining if the most recent read requested the exact number of bytes remaining
in the file.

=cut

*/

    METHOD eof() {
        const INTVAL flags = Parrot_io_eof(INTERP, SELF);
        RETURN(INTVAL flags);
    }


/*

=item C<METHOD handle()>

Returns the INTVAL used by the OS to identify this filehandle.

=cut

*/

    METHOD handle() {
        INTVAL handle;
        GET_ATTR_os_handle(INTERP, SELF, handle);
        RETURN(INTVAL handle);
    }

/*

=item C<METHOD exit_status()>

If this is a pipe, return the exit status of the child process.

=cut

*/
    METHOD exit_status() {
        INTVAL exit_status;
        GET_ATTR_exit_status(INTERP, SELF, exit_status);
        RETURN(INTVAL exit_status);
    }


/*

=item C<METHOD tell()>

Get the file position of the stream. 2 C<INTVAL>s are returned. The first is
the position. The second is the position shifted down by 32 bits to handle
overflows on 32-bit systems.

=cut

*/

    METHOD tell() {
        PIOOFF_T pos;
        GET_ATTR_file_pos(INTERP, SELF, pos);
        RETURN(INTVAL pos, INTVAL pos >> 32);
    }

/*

=item C<METHOD seek(INTVAL whence, INTVAL offs, INTVAL offs_overflow)>

Set the file position to an offset specified by C<offs> (and optionally
C<offs_overflow>). C<whence> determines from where in the file the offset is
taken.

 Whence Value      Meaning
 0                 Seek from the beginning of the file
 1                 Seek from the current position
 2                 Seek from the end of the file

C<offs_overflow> is optional and is used to handle offsets higher than 2Gb on
32bit systems.

=cut

*/

    METHOD seek(INTVAL whence, INTVAL offs, INTVAL offs_overflow :optional,
                int has_overflow :opt_flag) {
        const PIOOFF_T pio_offs = has_overflow ?
                                    Parrot_io_make_offset32(offs_overflow, offs) :
                                    offs;
        if (0 > Parrot_io_seek_handle(INTERP, SELF, pio_offs, whence))
            Parrot_ex_throw_from_c_args(INTERP, NULL, EXCEPTION_PIO_ERROR, "seek failed");
    }

/*

=item C<METHOD peek()>

Returns the next byte from the stream, but does not remove it.

=cut

*/

    METHOD peek() {
        STRING * const s = Parrot_io_peek(INTERP, SELF);
        RETURN(STRING* s);
    }

/*

=item C<METHOD setasync()>

=cut

*/
    METHOD setasync() {
        Parrot_io_async(INTERP, SELF, 1);
    }

/*

=item C<METHOD setblocking()>

=cut

*/
    METHOD setblocking() {
        Parrot_io_async(INTERP, SELF, 0);
    }

/*

=back

=cut

*/


} /* end pmclass */

/*
 * Local variables:
 *   c-file-style: "parrot"
 * End:
 * vim: expandtab shiftwidth=4 cinoptions='\:2=2' :
 */