path: root/modules/prefer-plain/e-mail-parser-prefer-plain.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/>
 */

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

#include <string.h>
#include <gtk/gtk.h>
#include <glib/gi18n.h>

#include "e-mail-parser-prefer-plain.h"

#include <em-format/e-mail-extension-registry.h>
#include <em-format/e-mail-parser-extension.h>
#include <em-format/e-mail-part.h>
#include <em-format/e-mail-part-utils.h>

#include <libebackend/libebackend.h>

#define d(x)

typedef struct _EMailParserPreferPlain {
    EExtension parent;

    GSettings *settings;
    gint mode;
    gboolean show_suppressed;
} EMailParserPreferPlain;

typedef struct _EMailParserPreferPlainClass {
    EExtensionClass parent_class;
} EMailParserPreferPlainClass;

GType e_mail_parser_prefer_plain_get_type (void);
static void e_mail_parser_mail_extension_interface_init (EMailExtensionInterface *iface);
static void e_mail_parser_parser_extension_interface_init (EMailParserExtensionInterface *iface);

enum {
    EPP_NORMAL,
    EPP_PREFER,
    EPP_TEXT
};

G_DEFINE_DYNAMIC_TYPE_EXTENDED (
    EMailParserPreferPlain,
    e_mail_parser_prefer_plain,
    E_TYPE_EXTENSION,
    0,
    G_IMPLEMENT_INTERFACE_DYNAMIC (
        E_TYPE_MAIL_EXTENSION,
        e_mail_parser_mail_extension_interface_init)
    G_IMPLEMENT_INTERFACE_DYNAMIC (
        E_TYPE_MAIL_PARSER_EXTENSION,
        e_mail_parser_parser_extension_interface_init));

static const gchar* parser_mime_types[] = { "multipart/alternative",
                        "text/html",
                        NULL };

static struct {
    const gchar *key;
    const gchar *label;
    const gchar *description;
} epp_options[] = {
    { "normal",
      N_("Show HTML if present"),
      N_("Let Evolution choose the best part to show.") },

    { "prefer_plain",
      N_("Show plain text if present"),
      N_("Show plain text part, if present, otherwise "
         "let Evolution choose the best part to show.") },

    { "only_plain",
      N_("Only ever show plain text"),
      N_("Always show plain text part and make attachments "
         "from other parts, if requested.") },
};

enum {
    PROP_0,
    PROP_MODE,
    PROP_SHOW_SUPPRESSED
};

static GSList *
make_part_attachment (EMailParser *parser,
                      CamelMimePart *part,
                      GString *part_id,
                      gboolean force_html,
                      GCancellable *cancellable)
{
    GSList *parts;

    if (camel_content_type_is (camel_mime_part_get_content_type (part), "text", "html")) {
        EMailPart *mail_part;
        gint len;
        /* always show HTML as attachments and not inline */
        camel_mime_part_set_disposition (part, "attachment");

        if (!camel_mime_part_get_filename (part)) {
            gchar *str = g_strdup_printf ("%s.html", _("attachment"));
            camel_mime_part_set_filename (part, str);
            g_free (str);
        }

        len = part_id->len;
        g_string_append (part_id, ".text_html");
        mail_part = e_mail_part_new (part, part_id->str);
        mail_part->mime_type = g_strdup ("text/html");
        g_string_truncate (part_id, len);

        parts = e_mail_parser_wrap_as_attachment (
                parser, part, g_slist_append (NULL, mail_part),
                part_id, cancellable);

    } else if (force_html && CAMEL_IS_MIME_MESSAGE (part)) {
        /* message was asked to be formatted as text/html;
         * might be for cases where message itself is a text/html part */
        CamelMimePart *new_part;
        CamelDataWrapper *content;

        content = camel_medium_get_content (CAMEL_MEDIUM (part));
        g_return_val_if_fail (content != NULL, NULL);

        new_part = camel_mime_part_new ();
        camel_medium_set_content (CAMEL_MEDIUM (new_part), content);

        parts = e_mail_parser_parse_part (
                parser, new_part, part_id, cancellable);

        g_object_unref (new_part);
    } else {
        parts = e_mail_parser_parse_part (
                parser, part, part_id, cancellable);
    }

    return parts;
}

static GSList *
export_as_attachments (CamelMultipart *mp,
                       EMailParser *parser,
                       CamelMimePart *except,
                       GString *part_id,
                       GCancellable *cancellable)
{
    gint i, nparts;
    CamelMimePart *part;
    gint len;
    GSList *parts;

    if (!mp || !CAMEL_IS_MULTIPART (mp))
        return NULL;

    len = part_id->len;
    nparts = camel_multipart_get_number (mp);
    parts = NULL;
    for (i = 0; i < nparts; i++) {
        part = camel_multipart_get_part (mp, i);

        if (part != except) {
            CamelMultipart *multipart = (CamelMultipart *) camel_medium_get_content ((CamelMedium *) part);

            g_string_append_printf (part_id, ".aleternative-prefer-plain.%d", i);
            if (CAMEL_IS_MULTIPART (multipart)) {
                parts = g_slist_concat (parts,
                        export_as_attachments (
                            multipart, parser,
                            except, part_id,
                            cancellable));
            } else {
                parts = g_slist_concat (parts,
                        make_part_attachment (
                            parser, part, part_id,
                            FALSE, cancellable));
            }
            g_string_truncate (part_id, len);
        }
    }

    return parts;
}

static GSList *
empe_prefer_plain_parse (EMailParserExtension *extension,
                         EMailParser *parser,
                         CamelMimePart *part,
                         GString *part_id,
                         GCancellable *cancellable)
{
    EMailParserPreferPlain *emp_pp;
    CamelMultipart *mp;
    CamelMimePart *display_part = NULL, *calendar_part = NULL;
    gint i, nparts, partidlen, displayid = 0, calendarid = 0;
    GSList *parts;

    emp_pp = (EMailParserPreferPlain *) extension;

    /* We 'can' parse HTML as well!
     * The reason simply is to convert the HTML part to attachment in some
     * cases, otherwise we will return NULL and fallback to "normal" parser. */
    if (camel_content_type_is (camel_mime_part_get_content_type (part), "text", "html")) {
        GQueue *extensions;
        EMailExtensionRegistry *reg;

        reg = e_mail_parser_get_extension_registry (parser);
        extensions = e_mail_extension_registry_get_for_mime_type (
                    reg, "text/html");

        if (emp_pp->mode != EPP_TEXT
            || strstr (part_id->str, ".alternative-prefer-plain.") != NULL
            || e_mail_part_is_inline (part, extensions)) {

            return NULL;

        } else if (emp_pp->show_suppressed) {
            return make_part_attachment (
                parser, part, part_id,
                TRUE, cancellable);
        }

        /* Return an empty item. We MUST return something, otherwise
         * the parser would think we have failed to parse the part
         * and would let a fallback extension to parse it and we don't
         * want that... */
        /* FIXME: In theory we could parse it anyway and just set
         * is_hidden to TRUE....? */
        return g_slist_alloc ();
    }

    mp  = (CamelMultipart *) camel_medium_get_content ((CamelMedium *) part);
    partidlen = part_id->len;

    parts = NULL;
    if (emp_pp->mode == EPP_NORMAL) {
        gboolean have_plain = FALSE;

        /* Try to find text/html part even when not as last and force
         * to show it.  Old handler will show the last part of
         * multipart/alternate, but if we can offer HTML, then
         * offer it, regardless of position in multipart.  But do
         * this when have only text/plain and text/html parts,
         * not more. */
        nparts = camel_multipart_get_number (mp);
        for (i = 0; i < nparts; i++) {
            CamelContentType *content_type;

            part = camel_multipart_get_part (mp, i);

            if (!part)
                continue;

            content_type = camel_mime_part_get_content_type (part);

            if (camel_content_type_is (content_type, "text", "html")) {
                displayid = i;
                display_part = part;

                if (have_plain)
                    break;
            } else if (camel_content_type_is (content_type, "text", "plain")) {
                have_plain = TRUE;

                if (display_part)
                    break;
            }
        }

        if (display_part && have_plain && nparts == 2) {
            g_string_append_printf (part_id, ".alternative-prefer-plain.%d", displayid);
            /* FIXME Not passing a GCancellable here. */
            parts = e_mail_parser_parse_part_as (
                parser, display_part, part_id,
                "text/html", cancellable);

            g_string_truncate (part_id, partidlen);
        } else {
            /* Parser will automatically fallback to next extension */
            return NULL;

        }

        return parts;

    } else if (!CAMEL_IS_MULTIPART (mp)) {
        return e_mail_parser_parse_part_as (
            parser, part, part_id,
            "application/vnd.evolution.source", cancellable);
    }

    nparts = camel_multipart_get_number (mp);
    for (i = 0; i < nparts; i++) {
        CamelContentType *ct;

        part = camel_multipart_get_part (mp, i);

        if (!part)
            continue;

        ct = camel_mime_part_get_content_type (part);
        if (!display_part && camel_content_type_is (ct, "text", "plain")) {
            displayid = i;
            display_part = part;
        } else if (!calendar_part && (camel_content_type_is (ct, "text", "calendar") || camel_content_type_is (ct, "text", "x-calendar"))) {
            calendarid = i;
            calendar_part = part;
        }
    }

    /* if we found a text part, show it */
    if (display_part) {
        g_string_append_printf(part_id, ".alternative-prefer-plain.%d", displayid);
        parts = g_slist_concat (parts,
                e_mail_parser_parse_part_as (
                    parser, display_part, part_id,
                    "text/plain", cancellable));

        g_string_truncate (part_id, partidlen);
    }

    /* all other parts are attachments */
    if (emp_pp->show_suppressed) {
        parts = g_slist_concat (parts,
                export_as_attachments (
                    mp, parser, display_part, part_id,
                    cancellable));
    } else if (calendar_part) {
        g_string_append_printf(part_id, ".alternative-prefer-plain.%d", calendarid);
        parts = g_slist_concat (parts,
                make_part_attachment (
                    parser, calendar_part, part_id,
                    FALSE, NULL));
    }

    g_string_truncate (part_id, partidlen);

    return parts;
}

static const gchar **
empe_mime_types (EMailExtension *extension)
{
    return parser_mime_types;
}

void
e_mail_parser_prefer_plain_type_register (GTypeModule *type_module)
{
    e_mail_parser_prefer_plain_register_type (type_module);
}

static void
e_mail_parser_mail_extension_interface_init (EMailExtensionInterface *iface)
{
    iface->mime_types = empe_mime_types;
}

static void
e_mail_parser_parser_extension_interface_init (EMailParserExtensionInterface *iface)
{
    iface->parse = empe_prefer_plain_parse;
}

static void
e_mail_parser_prefer_plain_constructed (GObject *object)
{
    EExtensible *extensible;
    EMailExtensionRegistry *reg;

    extensible = e_extension_get_extensible (E_EXTENSION (object));
    reg = E_MAIL_EXTENSION_REGISTRY (extensible);

    e_mail_extension_registry_add_extension (reg, E_MAIL_EXTENSION (object));
}

static void
e_mail_parser_prefer_plain_get_property (GObject *object,
                                         guint property_id,
                                         GValue *value,
                                         GParamSpec *pspec)
{
    EMailParserPreferPlain *parser;

    parser = (EMailParserPreferPlain *) object;

    switch (property_id) {
        case PROP_MODE:
            g_value_set_int (value, parser->mode);
            return;
        case PROP_SHOW_SUPPRESSED:
            g_value_set_boolean (value, parser->show_suppressed);
            return;
    }

    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
}

static void
e_mail_parser_prefer_plain_set_property (GObject *object,
                                         guint property_id,
                                         const GValue *value,
                                         GParamSpec *pspec)
{
    EMailParserPreferPlain *parser;

    parser = (EMailParserPreferPlain *) object;

    switch (property_id) {
        case PROP_MODE:
            parser->mode = g_value_get_int (value);
            return;
        case PROP_SHOW_SUPPRESSED:
            parser->show_suppressed = g_value_get_boolean (value);
            return;
    }

    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
}

static void
e_mail_parser_prefer_plain_finalize (GObject *object)
{
    EMailParserPreferPlain *parser;

    parser = (EMailParserPreferPlain *) object;

    g_clear_object (&parser->settings);

    G_OBJECT_CLASS (e_mail_parser_prefer_plain_parent_class)->finalize (object);
}

static void
e_mail_parser_prefer_plain_class_init (EMailParserPreferPlainClass *klass)
{
    GObjectClass *object_class;
    EExtensionClass *extension_class;

    e_mail_parser_prefer_plain_parent_class = g_type_class_peek_parent (klass);

    object_class = G_OBJECT_CLASS (klass);
    object_class->constructed = e_mail_parser_prefer_plain_constructed;
    object_class->get_property = e_mail_parser_prefer_plain_get_property;
    object_class->set_property = e_mail_parser_prefer_plain_set_property;
    object_class->finalize = e_mail_parser_prefer_plain_finalize;

    extension_class = E_EXTENSION_CLASS (klass);
    extension_class->extensible_type = E_TYPE_MAIL_PARSER_EXTENSION_REGISTRY;

    g_object_class_install_property (
        object_class,
        PROP_MODE,
        g_param_spec_int (
            "mode",
            "Mode",
            NULL,
            EPP_NORMAL,
            EPP_TEXT,
            EPP_NORMAL,
            G_PARAM_READABLE | G_PARAM_WRITABLE));

    g_object_class_install_property (
        object_class,
        PROP_SHOW_SUPPRESSED,
        g_param_spec_boolean (
            "show-suppressed",
            "Show Suppressed",
            NULL,
            FALSE,
            G_PARAM_READABLE | G_PARAM_WRITABLE));
}

void
e_mail_parser_prefer_plain_class_finalize (EMailParserPreferPlainClass *klass)
{
}

static gboolean
parser_mode_get_mapping (GValue *value,
                         GVariant *variant,
                         gpointer user_data)
{
    gint i;

    const gchar *key = g_variant_get_string (variant, NULL);
    if (key) {
        for (i = 0; i < G_N_ELEMENTS (epp_options); i++) {
            if (!strcmp (epp_options[i].key, key)) {
                g_value_set_int (value, i);
                return TRUE;
            }
        }
    } else {
        g_value_set_int (value, 0);
    }

    return TRUE;
}

static GVariant *
parser_mode_set_mapping (const GValue *value,
                         const GVariantType *expected_type,
                         gpointer user_data)
{
    return g_variant_new_string (epp_options[g_value_get_int (value)].key);
}

static void
e_mail_parser_prefer_plain_init (EMailParserPreferPlain *parser)
{
    gchar *key;
    gint i;

    parser->settings = g_settings_new ("org.gnome.evolution.plugin.prefer-plain");
    g_settings_bind_with_mapping (
        parser->settings, "mode",
        parser, "mode", G_SETTINGS_BIND_DEFAULT,
        parser_mode_get_mapping,
        parser_mode_set_mapping,
        NULL, NULL);
    g_settings_bind (
        parser->settings, "show-suppressed",
        parser, "show-suppressed", G_SETTINGS_BIND_DEFAULT);

    /* Initialize the settings */
    key = g_settings_get_string (parser->settings, "mode");
    if (key) {
        for (i = 0; i < G_N_ELEMENTS (epp_options); i++) {
            if (!strcmp (epp_options[i].key, key)) {
                parser->mode = i;
                break;
            }
        }
        g_free (key);
    } else {
        parser->mode = 0;
    }

    parser->show_suppressed = g_settings_get_boolean (parser->settings, "show-suppressed");
}