path: root/mail/em-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 "em-inline-filter.h"

#include "em-utils.h"
#include "em-format/em-format.h"

#define d(x)

G_DEFINE_TYPE (EMInlineFilter, em_inline_filter, CAMEL_TYPE_MIME_FILTER)

enum {
    EMIF_PLAIN,
    EMIF_UUENC,
    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", "octet-stream",          CAMEL_TRANSFER_ENCODING_UUENCODE, 0, },
    { "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 void
inline_filter_add_part(EMInlineFilter *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);
    emif->data = g_byte_array_new();

    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 (dw, filter_stream, NULL);

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

    if (emif_types[emif->state].plain && emif->base_type) {
        camel_content_type_ref (emif->base_type);
        content_type = emif->base_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 = em_format_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 gint
inline_filter_scan(CamelMimeFilter *f, gchar *in, gsize len, gint final)
{
    EMInlineFilter *emif = (EMInlineFilter *)f;
    gchar *inptr = in, *inend = in+len;
    gchar *data_start = in;
    gchar *start;

    while (inptr < inend) {
        gint rest_len;

        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;

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

        switch (emif->state) {
        case EMIF_PLAIN:
            /* This could use some funky plugin, but this'll do for now */
            if (rest_len > 6 && strncmp (start, "begin ", 6) == 0
                && start[6] >= '0' && start[6] <= '7') {
                gint i = 7;
                gchar *name;

                while (i < rest_len && start[i] >='0' && start[i] <='7')
                    i++;

                restore_inptr ();

                if (i >= rest_len || start[i++] != ' ')
                    break;

                inline_filter_add_part(emif, data_start, start-data_start);

                name = g_strndup(start+i, inptr-start-i-1);
                emif->filename = camel_header_decode_string(name, emif->base_type?camel_content_type_param(emif->base_type, "charset"):NULL);
                g_free(name);
                data_start = start;
                emif->state = EMIF_UUENC;
            } else 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) {
                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) {
                restore_inptr ();
                inline_filter_add_part(emif, data_start, start-data_start);
                data_start = start;
                emif->state = EMIF_PGPENCRYPTED;
            }

            break;
        case EMIF_UUENC:
            if (rest_len >= 3 && strncmp (start, "end", 3) == 0) {
                restore_inptr ();
                inline_filter_add_part(emif, data_start, inptr-data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
            } else {
                gint linelen;

                /* check the length byte matches the data, if not, output what we have and re-scan this line */
                len = ((start[0] - ' ') & 077);
                linelen = inptr-start-1;
                while (linelen > 0 && (start[linelen] == '\r' || start[linelen] == '\n'))
                    linelen--;
                linelen--;
                linelen /= 4;
                linelen *= 3;
                if (!(len == linelen || len == linelen-1 || len == linelen-2)) {
                    restore_inptr ();
                    inline_filter_add_part(emif, data_start, start-data_start);
                    data_start = start;
                    inptr = start;
                    emif->state = EMIF_PLAIN;
                    continue;
                }
            }
            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;
            }
            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;
            }
            break;
        case EMIF_PGPSIGNED:
            if (rest_len >= 27 && strncmp (start, "-----END PGP SIGNATURE-----", 27) == 0) {
                restore_inptr ();
                inline_filter_add_part(emif, data_start, inptr-data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
            }
            break;
        case EMIF_PGPENCRYPTED:
            if (rest_len >= 25 && strncmp (start, "-----END PGP MESSAGE-----", 25) == 0) {
                restore_inptr ();
                inline_filter_add_part(emif, data_start, inptr-data_start);
                data_start = inptr;
                emif->state = EMIF_PLAIN;
            }
            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 {
        g_byte_array_append(emif->data, (guchar *)data_start, inend-data_start);
    }

    return 0;
}

static void
inline_filter_finalize (GObject *object)
{
    EMInlineFilter *emif = EM_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 (em_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)
{
    EMInlineFilter *emif = EM_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);
}

static void
em_inline_filter_class_init (EMInlineFilterClass *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
em_inline_filter_init (EMInlineFilter *emif)
{
    emif->data = g_byte_array_new();
}

/**
 * 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.
 *
 * Create a filter which will scan a (text) stream for
 * embedded parts.  You can then retrieve the contents
 * as a CamelMultipart object.
 *
 * Return value:
 **/
EMInlineFilter *
em_inline_filter_new(CamelTransferEncoding base_encoding, CamelContentType *base_type)
{
    EMInlineFilter *emif;

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

    return emif;
}

CamelMultipart *
em_inline_filter_get_multipart(EMInlineFilter *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;
}