path: root/camel/camel-stream-fs.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-stream-fs.c : file system based stream */

/*
 * Authors: Bertrand Guiheneuf <bertrand@helixcode.com>
 *      Michael Zucchi <notzed@helixcode.com>
 *
 * Copyright 1999, 2000 Helix Code, Inc. (http://www.helixcode.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

#include <config.h>
#include "camel-stream-fs.h"
#include "camel-exception.h"
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>

static CamelSeekableStreamClass *parent_class = NULL;

/* Returns the class for a CamelStreamFS */
#define CSFS_CLASS(so) CAMEL_STREAM_FS_CLASS (GTK_OBJECT(so)->klass)

static int stream_read   (CamelStream *stream, char *buffer, unsigned int n,
              CamelException *ex);
static int stream_write  (CamelStream *stream, const char *buffer,
              unsigned int n, CamelException *ex);
static void stream_flush (CamelStream *stream, CamelException *ex);
static off_t stream_seek (CamelSeekableStream *stream, off_t offset,
              CamelStreamSeekPolicy policy,
              CamelException *ex);

static void finalize (GtkObject *object);

static void
camel_stream_fs_class_init (CamelStreamFsClass *camel_stream_fs_class)
{
    CamelSeekableStreamClass *camel_seekable_stream_class =
        CAMEL_SEEKABLE_STREAM_CLASS (camel_stream_fs_class);
    CamelStreamClass *camel_stream_class =
        CAMEL_STREAM_CLASS (camel_stream_fs_class);
    GtkObjectClass *gtk_object_class =
        GTK_OBJECT_CLASS (camel_stream_fs_class);

    parent_class = gtk_type_class (camel_seekable_stream_get_type ());

    /* virtual method overload */
    camel_stream_class->read = stream_read;
    camel_stream_class->write = stream_write;
    camel_stream_class->flush = stream_flush;

    camel_seekable_stream_class->seek = stream_seek;

    gtk_object_class->finalize = finalize;
}

static void
camel_stream_fs_init (gpointer object, gpointer klass)
{
    CamelStreamFs *stream = CAMEL_STREAM_FS (object);

    stream->fd = -1;
}

GtkType
camel_stream_fs_get_type (void)
{
    static GtkType camel_stream_fs_type = 0;

    if (!camel_stream_fs_type) {
        GtkTypeInfo camel_stream_fs_info =
        {
            "CamelStreamFs",
            sizeof (CamelStreamFs),
            sizeof (CamelStreamFsClass),
            (GtkClassInitFunc) camel_stream_fs_class_init,
            (GtkObjectInitFunc) camel_stream_fs_init,
                /* reserved_1 */ NULL,
                /* reserved_2 */ NULL,
            (GtkClassInitFunc) NULL,
        };

        camel_stream_fs_type = gtk_type_unique (camel_seekable_stream_get_type (), &camel_stream_fs_info);
    }

    return camel_stream_fs_type;
}

static void
finalize (GtkObject *object)
{
    CamelStreamFs *stream_fs = CAMEL_STREAM_FS (object);

    if (stream_fs->fd != -1)
        close (stream_fs->fd);

    GTK_OBJECT_CLASS (parent_class)->finalize (object);
}

/**
 * camel_stream_fs_new_with_fd:
 * @fd: a file descriptor
 *
 * Returns a stream associated with the given file descriptor.
 * When the stream is destroyed, the file descriptor will be closed.
 *
 * Return value: the stream
 **/
CamelStream *
camel_stream_fs_new_with_fd (int fd)
{
    CamelStreamFs *stream_fs;
    off_t offset;

    stream_fs = gtk_type_new (camel_stream_fs_get_type ());
    stream_fs->fd = fd;
    offset = lseek (fd, 0, SEEK_CUR);
    if (offset == -1)
        offset = 0;
    CAMEL_SEEKABLE_STREAM (stream_fs)->position = offset;

    return CAMEL_STREAM (stream_fs);
}

/**
 * camel_stream_fs_new_with_fd_and_bounds:
 * @fd: a file descriptor
 * @start: the first valid position in the file
 * @end: the first invalid position in the file, or CAMEL_STREAM_UNBOUND
 *
 * Returns a stream associated with the given file descriptor and bounds.
 * When the stream is destroyed, the file descriptor will be closed.
 *
 * Return value: the stream
 **/
CamelStream *
camel_stream_fs_new_with_fd_and_bounds (int fd, off_t start, off_t end,
                    CamelException *ex)
{
    CamelStream *stream;

    stream = camel_stream_fs_new_with_fd (fd);
    camel_seekable_stream_set_bounds (CAMEL_SEEKABLE_STREAM (stream),
                      start, end, ex);

    return stream;
}

/**
 * camel_stream_fs_new_with_name:
 * @name: a local filename
 * @flags: flags as in open(2)
 * @mode: a file mode
 * @ex: a CamelException.
 *
 * Creates a new CamelStream corresponding to the named file, flags,
 * and mode. If an error occurs, @ex will be set.
 *
 * Return value: the stream
 **/
CamelStream *
camel_stream_fs_new_with_name (const char *name, int flags, mode_t mode,
                   CamelException *ex)
{
    CamelStream *stream;
    int fd;

    fd = open (name, flags, mode);
    if (fd == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      "Could not open file %s: %s.",
                      name, g_strerror (errno));
        return NULL;
    }

    stream = camel_stream_fs_new_with_fd (fd);

    return stream;
}

/**
 * camel_stream_fs_new_with_name_and_bounds:
 * @name: a local filename
 * @flags: flags as in open(2)
 * @mode: a file mode
 * @start: the first valid position in the file
 * @end: the first invalid position in the file, or CAMEL_STREAM_UNBOUND
 * @ex: a CamelException.
 *
 * Creates a new CamelStream corresponding to the given arguments. If
 * an error occurs, @ex will be set.
 *
 * Return value: the stream
 **/
CamelStream *
camel_stream_fs_new_with_name_and_bounds (const char *name, int flags,
                      mode_t mode, off_t start, off_t end,
                      CamelException *ex)
{
    CamelStream *stream;

    stream = camel_stream_fs_new_with_name (name, flags, mode, ex);
    if (camel_exception_is_set (ex))
        return NULL;

    camel_seekable_stream_set_bounds (CAMEL_SEEKABLE_STREAM (stream),
                      start, end, ex);
    if (camel_exception_is_set (ex)) {
        gtk_object_unref (GTK_OBJECT (stream));
        return NULL;
    }

    return stream;
}


static int
stream_read (CamelStream *stream, char *buffer, unsigned int n,
         CamelException *ex)
{
    CamelStreamFs *stream_fs = CAMEL_STREAM_FS (stream);
    CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
    int nread;

    if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
        n = MIN (seekable->bound_end - seekable->position, n);

    do {
        nread = read (stream_fs->fd, buffer, n);
    } while (nread == -1 && errno == EINTR);

    if (nread > 0)
        seekable->position += nread;
    else if (nread == 0)
        stream->eos = TRUE;
    else {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      "Could not read from stream: %s",
                      g_strerror (errno));
    }

    return nread;
}

static int
stream_write (CamelStream *stream, const char *buffer, unsigned int n,
          CamelException *ex)
{
    CamelStreamFs *stream_fs = CAMEL_STREAM_FS (stream);
    CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
    int v, written = 0;

    if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
        n = MIN (seekable->bound_end - seekable->position, n);

    do {
        v = write (stream_fs->fd, buffer, n);
        if (v > 0)
            written += v;
    } while (v == -1 && errno == EINTR);

    if (written > 0)
        seekable->position += written;
    else if (v == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      "Could not write to stream: %s",
                      g_strerror (errno));
    }

    return written;
}

static void
stream_flush (CamelStream *stream, CamelException *ex)
{
    if (fsync (CAMEL_STREAM_FS (stream)->fd) == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      "Could not flush stream data: %s",
                      g_strerror (errno));
    }
}

static off_t
stream_seek (CamelSeekableStream *stream, off_t offset,
         CamelStreamSeekPolicy policy, CamelException *ex)
{
    CamelStreamFs *stream_fs = CAMEL_STREAM_FS (stream);
    off_t real = 0;

    switch  (policy) {
    case CAMEL_STREAM_SET:
        real = offset;
        break;
    case CAMEL_STREAM_CUR:
        real = stream->position + offset;
        break;
    case CAMEL_STREAM_END:
        if (stream->bound_end != CAMEL_STREAM_UNBOUND) {
            real = lseek(stream_fs->fd, offset, SEEK_END);
            if (real != -1)
                stream->position = real;
            else {
                camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                              "Could not seek to "
                              "given offset: %s",
                              g_strerror (errno));
            }
            return real;
        }
        real = stream->bound_end + offset;
        break;
    }

    if (stream->bound_end != CAMEL_STREAM_UNBOUND)
        real = MIN (real, stream->bound_end);
    real = MAX (real, stream->bound_start);

    real = lseek(stream_fs->fd, real, SEEK_SET);
    if (real == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      "Could not seek to given offset: %s",
                      g_strerror (errno));
        return -1;
    }

    if (real != stream->position && ((CamelStream *)stream)->eos)
        ((CamelStream *)stream)->eos = FALSE;

    stream->position = real;

    return real;
}