path: root/em-format/e-mail-inline-filter.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Michael Zucchi <notzed@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>

#include "e-mail-inline-filter.h"
#include "e-mail-part-utils.h"

#define d(x)

G_DEFINE_TYPE (EMailInlineFilter, e_mail_inline_filter, CAMEL_TYPE_MIME_FILTER)

enum {
    EMIF_PLAIN,
    EMIF_BINHEX,
    EMIF_POSTSCRIPT,
    EMIF_PGPSIGNED,
    EMIF_PGPENCRYPTED
};

static const struct {
    const gchar *type;
    const gchar *subtype;
    CamelTransferEncoding encoding;
    guint plain : 1;
} emif_types[] = {
    { "text", "plain",
      CAMEL_TRANSFER_ENCODING_DEFAULT, 1 },

    { "application", "mac-binhex40",
      CAMEL_TRANSFER_ENCODING_7BIT, 0 },

    { "application", "postscript",
      CAMEL_TRANSFER_ENCODING_7BIT, 0 },

    { "application", "x-inlinepgp-signed",
      CAMEL_TRANSFER_ENCODING_DEFAULT, 0 },

    { "application", "x-inlinepgp-encrypted",
      CAMEL_TRANSFER_ENCODING_DEFAULT, 0 }
};

static CamelMimePart *
construct_part_from_stream (CamelStream *mem,
                            const GByteArray *data)
{
    CamelMimePart *part = NULL;
    CamelMimeParser *parser;

    g_return_val_if_fail (mem != NULL, NULL);
    g_return_val_if_fail (data != NULL, NULL);

    if (data->len <= 13 || g_ascii_strncasecmp ((const gchar *) data->data, "Content-Type:", 13) != 0)
        return NULL;

    parser = camel_mime_parser_new ();
    camel_mime_parser_scan_from (parser, FALSE);
    camel_mime_parser_scan_pre_from (parser, FALSE);

    if (camel_mime_parser_init_with_stream (parser, mem, NULL) != -1) {
        part = camel_mime_part_new ();
        if (!camel_mime_part_construct_from_parser_sync (part, parser, NULL, NULL)) {
            g_object_unref (part);
            part = NULL;
        }
    }

    g_object_unref (parser);

    return part;
}

static void
inline_filter_add_part (EMailInlineFilter *emif,
                        const gchar *data,
                        gint len)
{
    CamelTransferEncoding encoding;
    CamelContentType *content_type;
    CamelDataWrapper *dw;
    const gchar *mimetype;
    CamelMimePart *part;
    CamelStream *mem;
    gchar *type;

    if (emif->state == EMIF_PLAIN || emif->state == EMIF_PGPSIGNED || emif->state == EMIF_PGPENCRYPTED)
        encoding = emif->base_encoding;
    else
        encoding = emif_types[emif->state].encoding;

    g_byte_array_append (emif->data, (guchar *) data, len);
    /* check the part will actually have content */
    if (emif->data->len <= 0) {
        return;
    }

    mem = camel_stream_mem_new_with_byte_array (emif->data);
    part = construct_part_from_stream (mem, emif->data);
    if (part) {
        g_object_unref (mem);
        emif->data = g_byte_array_new ();
        g_free (emif->filename);
        emif->filename = NULL;

        emif->parts = g_slist_append (emif->parts, part);
        emif->found_any = TRUE;

        return;
    }

    emif->data = g_byte_array_new ();
    g_seekable_seek (G_SEEKABLE (mem), 0, G_SEEK_SET, NULL, NULL);

    dw = camel_data_wrapper_new ();
    if (encoding == emif->base_encoding && (encoding == CAMEL_TRANSFER_ENCODING_BASE64 || encoding == CAMEL_TRANSFER_ENCODING_QUOTEDPRINTABLE)) {
        CamelMimeFilter *enc_filter = camel_mime_filter_basic_new (encoding == CAMEL_TRANSFER_ENCODING_BASE64 ? CAMEL_MIME_FILTER_BASIC_BASE64_ENC : CAMEL_MIME_FILTER_BASIC_QP_ENC);
        CamelStream *filter_stream;

        filter_stream = camel_stream_filter_new (mem);
        camel_stream_filter_add (CAMEL_STREAM_FILTER (filter_stream), enc_filter);

        /* properly encode content */
        camel_data_wrapper_construct_from_stream_sync (
            dw, filter_stream, NULL, NULL);

        g_object_unref (enc_filter);
        g_object_unref (filter_stream);
    } else {
        camel_data_wrapper_construct_from_stream_sync (
            dw, mem, NULL, NULL);
    }
    g_object_unref (mem);

    if (emif_types[emif->state].plain && emif->base_type) {
        /* create a copy */
        type = camel_content_type_format (emif->base_type);
        content_type = camel_content_type_decode (type);
        g_free (type);
    } else {
        /* we want to preserve all params */
        type = camel_content_type_format (emif->base_type);
        content_type = camel_content_type_decode (type);
        g_free (type);

        g_free (content_type->type);
        g_free (content_type->subtype);
        content_type->type = g_strdup (emif_types[emif->state].type);
        content_type->subtype = g_strdup (emif_types[emif->state].subtype);
    }

    camel_data_wrapper_set_mime_type_field (dw, content_type);
    camel_content_type_unref (content_type);
    dw->encoding = encoding;

    part = camel_mime_part_new ();
    camel_medium_set_content ((CamelMedium *) part, dw);
    camel_mime_part_set_encoding (part, encoding);
    g_object_unref (dw);

    if (emif->filename)
        camel_mime_part_set_filename (part, emif->filename);

    /* pre-snoop the mime type of unknown objects, and poke and hack it into place */
    if (camel_content_type_is (dw->mime_type, "application", "octet-stream")
        && (mimetype = e_mail_part_snoop_type (part))
        && strcmp (mimetype, "application/octet-stream") != 0) {
        camel_data_wrapper_set_mime_type (dw, mimetype);
        camel_mime_part_set_content_type (part, mimetype);
        if (emif->filename)
            camel_mime_part_set_filename (part, emif->filename);
    }

    g_free (emif->filename);
    emif->filename = NULL;

    emif->parts = g_slist_append (emif->parts, part);
}

static gboolean
newline_or_whitespace_follows (const gchar *str,
                               guint len,
                               guint skip_first)
{
    if (len <= skip_first)
        return len == skip_first;

    str += skip_first;
    len -= skip_first;

    while (len > 0 && *str != '\n') {
        if (!*str)
            return TRUE;

        if (!camel_mime_is_lwsp (*str))
            return FALSE;

        len--;
        str++;
    }

    return len == 0 || *str == '\n';
}

static gint
inline_filter_scan (CamelMimeFilter *f,
                    gchar *in,
                    gsize len,
                    gint final)
{
    EMailInlineFilter *emif = (EMailInlineFilter *) f;
    gchar *inptr = in, *inend = in + len;
    gchar *data_start = in;
    gchar *start = in;

    while (inptr < inend) {
        gint rest_len;
        gboolean set_null_byte = FALSE;

        start = inptr;

        while (inptr < inend && *inptr != '\n')
            inptr++;

        if (inptr == inend && start == inptr) {
            if (!final) {
                camel_mime_filter_backup (f, start, inend - start);
                inend = start;
            }
            break;
        }

        rest_len = inend - start;
        if (inptr < inend) {
            *inptr++ = 0;
            set_null_byte = TRUE;
        }

        #define restore_inptr() G_STMT_START { if (set_null_byte) inptr[-1] = '\n'; } G_STMT_END

        switch (emif->state) {
        case EMIF_PLAIN:
            if (rest_len >= 45 && strncmp (start, "(This file must be converted with BinHex 4.0)", 45) == 0) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, start - data_start);
                data_start = start;
                emif->state = EMIF_BINHEX;
            } else if (rest_len >= 11 && strncmp (start, "%!PS-Adobe-", 11) == 0) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, start - data_start);
                data_start = start;
                emif->state = EMIF_POSTSCRIPT;
            } else if (rest_len >= 34 && strncmp (start, "-----BEGIN PGP SIGNED MESSAGE-----", 34) == 0 &&
                   newline_or_whitespace_follows (start, rest_len, 34)) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, start - data_start);
                data_start = start;
                emif->state = EMIF_PGPSIGNED;
            } else if (rest_len >= 27 && strncmp (start, "-----BEGIN PGP MESSAGE-----", 27) == 0 &&
                   newline_or_whitespace_follows (start, rest_len, 27)) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, start - data_start);
                data_start = start;
                emif->state = EMIF_PGPENCRYPTED;
            }

            break;
        case EMIF_BINHEX:
            if (inptr > (start + 1) && inptr[-2] == ':') {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, inptr - data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
                emif->found_any = TRUE;
            }
            break;
        case EMIF_POSTSCRIPT:
            if (rest_len >= 5 && strncmp (start, "%%EOF", 5) == 0) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, inptr - data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
                emif->found_any = TRUE;
            }
            break;
        case EMIF_PGPSIGNED:
            if (rest_len >= 27 && strncmp (start, "-----END PGP SIGNATURE-----", 27) == 0 &&
                newline_or_whitespace_follows (start, rest_len, 27)) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, inptr - data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
                emif->found_any = TRUE;
            }
            break;
        case EMIF_PGPENCRYPTED:
            if (rest_len >= 25 && strncmp (start, "-----END PGP MESSAGE-----", 25) == 0 &&
                newline_or_whitespace_follows (start, rest_len, 25)) {
                restore_inptr ();
                inline_filter_add_part (emif, data_start, inptr - data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
                emif->found_any = TRUE;
            }
            break;
        }

        restore_inptr ();

        #undef restore_inptr
    }

    if (final) {
        /* always stop as plain, especially when not read those tags fully */
        emif->state = EMIF_PLAIN;

        inline_filter_add_part (emif, data_start, inend - data_start);
    } else if (start > data_start) {
        /* backup the last line, in case the tag is divided within buffers */
        camel_mime_filter_backup (f, start, inend - start);
        g_byte_array_append (emif->data, (guchar *) data_start, start - data_start);
    } else {
        g_byte_array_append (emif->data, (guchar *) data_start, inend - data_start);
    }

    return 0;
}

static void
inline_filter_finalize (GObject *object)
{
    EMailInlineFilter *emif = E_MAIL_INLINE_FILTER (object);

    if (emif->base_type)
        camel_content_type_unref (emif->base_type);

    camel_mime_filter_reset (CAMEL_MIME_FILTER (object));
    g_byte_array_free (emif->data, TRUE);
    g_free (emif->filename);

    /* Chain up to parent's finalize() method. */
    G_OBJECT_CLASS (e_mail_inline_filter_parent_class)->finalize (object);
}

static void
inline_filter_filter (CamelMimeFilter *filter,
                      const gchar *in,
                      gsize len,
                      gsize prespace,
                      gchar **out,
                      gsize *outlen,
                      gsize *outprespace)
{
    inline_filter_scan (filter, (gchar *) in, len, FALSE);

    *out = (gchar *)in;
    *outlen = len;
    *outprespace = prespace;
}

static void
inline_filter_complete (CamelMimeFilter *filter,
                        const gchar *in,
                        gsize len,
                        gsize prespace,
                        gchar **out,
                        gsize *outlen,
                        gsize *outprespace)
{
    inline_filter_scan (filter, (gchar *) in, len, TRUE);

    *out = (gchar *)in;
    *outlen = len;
    *outprespace = prespace;
}

static void
inline_filter_reset (CamelMimeFilter *filter)
{
    EMailInlineFilter *emif = E_MAIL_INLINE_FILTER (filter);
    GSList *l;

    l = emif->parts;
    while (l) {
        GSList *n = l->next;

        g_object_unref (l->data);
        g_slist_free_1 (l);

        l = n;
    }
    emif->parts = NULL;
    g_byte_array_set_size (emif->data, 0);
    emif->found_any = FALSE;
}

static void
e_mail_inline_filter_class_init (EMailInlineFilterClass *class)
{
    GObjectClass *object_class;
    CamelMimeFilterClass *mime_filter_class;

    object_class = G_OBJECT_CLASS (class);
    object_class->finalize = inline_filter_finalize;

    mime_filter_class = CAMEL_MIME_FILTER_CLASS (class);
    mime_filter_class->filter = inline_filter_filter;
    mime_filter_class->complete = inline_filter_complete;
    mime_filter_class->reset = inline_filter_reset;
}

static void
e_mail_inline_filter_init (EMailInlineFilter *emif)
{
    emif->data = g_byte_array_new ();
    emif->found_any = FALSE;
}

/**
 * em_inline_filter_new:
 * @base_encoding: The base transfer-encoding of the
 * raw data being processed.
 * @base_type: The base content-type of the raw data, should always be
 * text/plain.
 * @filename: Filename of the part, or NULL
 *
 * Create a filter which will scan a (text) stream for
 * embedded parts.  You can then retrieve the contents
 * as a CamelMultipart object.
 *
 * Return value:
 **/
EMailInlineFilter *
e_mail_inline_filter_new (CamelTransferEncoding base_encoding,
                          CamelContentType *base_type,
                          const gchar *filename)
{
    EMailInlineFilter *emif;

    emif = g_object_new (E_TYPE_MAIL_INLINE_FILTER, NULL);
    emif->base_encoding = base_encoding;
    if (base_type) {
        emif->base_type = base_type;
        camel_content_type_ref (emif->base_type);
    }

    if (filename && *filename)
        emif->filename = g_strdup (filename);

    return emif;
}

CamelMultipart *
e_mail_inline_filter_get_multipart (EMailInlineFilter *emif)
{
    GSList *l = emif->parts;
    CamelMultipart *mp;

    mp = camel_multipart_new ();
    while (l) {
        camel_multipart_add_part (mp, l->data);
        l = l->next;
    }

    return mp;
}

gboolean
e_mail_inline_filter_found_any (EMailInlineFilter *emif)
{
    g_return_val_if_fail (emif != NULL, FALSE);

    return emif->found_any;
}