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 EMailParserPreferPlain;
typedef struct _EMailParserPreferPlainClass EMailParserPreferPlainClass;

struct _EMailParserPreferPlain {
    EExtension parent;

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

struct _EMailParserPreferPlainClass {
    EExtensionClass parent_class;
};

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 {
    PREFER_HTML,
    PREFER_PLAIN,
    ONLY_PLAIN
};

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 void
hide_parts (GSList *parts)
{
    GSList *iter;

    for (iter = parts; iter; iter = g_slist_next (iter)) {
        EMailPart *p = iter->data;

        if (!p)
            continue;

        p->is_hidden = TRUE;
    }
}

static GSList *
empe_prefer_plain_parse (EMailParserExtension *extension,
                         EMailParser *parser,
                         CamelMimePart *part,
                         GString *part_id,
                         GCancellable *cancellable)
{
    EMailParserPreferPlain *emp_pp;
    CamelMultipart *mp;
    gint i, nparts, partidlen;
    GSList *parts;
    CamelContentType *ct;
    gboolean has_calendar = FALSE;
    GSList *plain_text_parts, *iter;
    GSList *plain_text_placeholder = NULL;

    emp_pp = (EMailParserPreferPlain *) extension;

    ct = camel_mime_part_get_content_type (part);

    /* We can actually parse HTML, but just to discard it when
     * "Only ever show plain text" mode is set */
    if (camel_content_type_is (ct, "text", "html")) {

        /* Prevent recursion, fall back to next (real text/html) parser */
        if (strstr (part_id->str, ".alternative-prefer-plain.") != NULL)
            return NULL;

        /* Not enforcing text/plain, so use real parser */
        if (emp_pp->mode != ONLY_PLAIN)
            return NULL;

        /* Enforcing text/plain, but wants HTML as attachment */
        if (emp_pp->show_suppressed) {
            return make_part_attachment (
                parser, part, part_id,
                FALSE, cancellable);
        }

        /* Enforcing text/plain, does not want HTML part as attachment
         * so return nothing (can't return NULL as parser would fall
         * back to next extension) */
        return g_slist_alloc ();
    }

    parts = NULL;
    partidlen = part_id->len;

    mp = (CamelMultipart *) camel_medium_get_content (CAMEL_MEDIUM (part));

    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);
    plain_text_parts = NULL;
    for (i = 0; i < nparts; i++) {

        CamelMimePart *sp;
        GSList *sparts = NULL;

        sp = camel_multipart_get_part (mp, i);
        ct = camel_mime_part_get_content_type (sp);

        g_string_truncate (part_id, partidlen);
        g_string_append_printf (part_id, ".alternative-prefer-plain.%d", i);

        if (camel_content_type_is (ct, "text", "html")) {

            if (emp_pp->mode != PREFER_HTML) {
                if (emp_pp->show_suppressed) {
                    sparts = make_part_attachment (
                        parser, sp, part_id,
                        FALSE, cancellable);
                }
            } else {
                sparts = e_mail_parser_parse_part (
                    parser, sp, part_id, cancellable);
            }

            parts = g_slist_concat (parts, sparts);
            continue;
        }

        if (camel_content_type_is (ct, "text", "plain")) {

            plain_text_parts = e_mail_parser_parse_part (
                        parser, sp, part_id, cancellable);

            /* Placeholder - we will replace it by the actual text/plain
             * parts later */
            plain_text_placeholder = g_slist_alloc ();
            parts = g_slist_concat (parts, plain_text_placeholder);
            continue;
        }

        /* Always show calendar part! */
        if (camel_content_type_is (ct, "text", "calendar") ||
            camel_content_type_is (ct, "text", "x-calendar")) {

            /* Hide everything else, displaying native calendar part only */
            hide_parts (parts);

            sparts = e_mail_parser_parse_part (
                    parser, sp, part_id, cancellable);

            parts = g_slist_concat (parts, sparts);
            has_calendar = TRUE;
            continue;
        }

        /* Multiparts can represent a text/html with inline images or so */
        if (camel_content_type_is (ct, "multipart", "*")) {
            GSList *iter;
            gboolean has_html = FALSE;

            sparts = e_mail_parser_parse_part (
                    parser, sp, part_id, cancellable);

            /* Check whether the multipart contains a text/html part */
            for (iter = sparts; iter; iter = g_slist_next (iter)) {
                EMailPart *p = iter->data;
                if (!p)
                    continue;

                if (strstr (p->id, ".text_html") != NULL) {
                    has_html = TRUE;
                    break;
                }
            }

            if (has_html && (emp_pp->mode != PREFER_HTML)) {
                if (emp_pp->show_suppressed) {
                    sparts =  e_mail_parser_wrap_as_attachment (
                            parser, sp, sparts, part_id,
                            cancellable);
                } else {
                    hide_parts (sparts);
                }
            }

            parts = g_slist_concat (parts, sparts);
            continue;
        }

        /* Parse everything else as an attachment */
        sparts = e_mail_parser_parse_part (
                parser, sp, part_id, cancellable);
        parts = g_slist_concat (
                parts,
                e_mail_parser_wrap_as_attachment (
                    parser, sp, sparts, part_id,
                    cancellable));
    }

    /* Don't hide the plain text if there's nothing else to display */
    if (has_calendar || (nparts > 1 && emp_pp->mode == PREFER_HTML)) {
        hide_parts (plain_text_parts);
    }

    /* Replace the plain_text_placeholder by the actual plain_text_parts */
    for (iter = parts; iter; iter = iter->next) {
        if (iter && iter->next == plain_text_placeholder) {
            break;
        }
    }
    plain_text_parts = g_slist_concat (plain_text_parts, plain_text_placeholder);
    parts = g_slist_concat (iter, plain_text_parts);

    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_dispose (GObject *object)
{
    EMailParserPreferPlain *parser;

    parser = (EMailParserPreferPlain *) object;

    g_clear_object (&parser->settings);

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

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

    object_class = G_OBJECT_CLASS (class);
    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->dispose = e_mail_parser_prefer_plain_dispose;

    extension_class = E_EXTENSION_CLASS (class);
    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,
            PREFER_HTML,
            ONLY_PLAIN,
            PREFER_HTML,
            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 *class)
{
}

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");
}