path: root/libemail-engine/e-mail-utils.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:
 *      Srinivasa Ragavan <sragavan@gnome.org>
 *
 *
 */

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <time.h>

#include <glib/gstdio.h>

#ifdef G_OS_WIN32
/* Work around namespace clobbage in <windows.h> */
#define DATADIR windows_DATADIR
#include <windows.h>
#undef DATADIR
#undef interface
#endif

#include <glib/gi18n.h>
#include <libebook/libebook.h>

#include <libemail-utils/mail-mt.h>

#include "e-mail-folder-utils.h"
#include "e-mail-session.h"
#include "e-mail-utils.h"
#include "mail-tools.h"

#define d(x)

/**
 * em_utils_folder_is_drafts:
 * @registry: an #ESourceRegistry
 * @folder: a #CamelFolder
 *
 * Decides if @folder is a Drafts folder.
 *
 * Returns %TRUE if this is a Drafts folder or %FALSE otherwise.
 **/
gboolean
em_utils_folder_is_drafts (ESourceRegistry *registry,
                           CamelFolder *folder)
{
    CamelFolder *local_drafts_folder;
    CamelSession *session;
    CamelStore *store;
    GList *list, *iter;
    gchar *folder_uri;
    gboolean is_drafts = FALSE;
    const gchar *extension_name;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    local_drafts_folder =
        e_mail_session_get_local_folder (
        E_MAIL_SESSION (session), E_MAIL_LOCAL_FOLDER_DRAFTS);

    if (folder == local_drafts_folder)
        return TRUE;

    folder_uri = e_mail_folder_uri_from_folder (folder);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    extension_name = E_SOURCE_EXTENSION_MAIL_COMPOSITION;
    list = e_source_registry_list_sources (registry, extension_name);

    for (iter = list; iter != NULL; iter = g_list_next (iter)) {
        ESource *source = E_SOURCE (iter->data);
        ESourceExtension *extension;
        const gchar *drafts_folder_uri;

        extension = e_source_get_extension (source, extension_name);

        drafts_folder_uri =
            e_source_mail_composition_get_drafts_folder (
            E_SOURCE_MAIL_COMPOSITION (extension));

        if (drafts_folder_uri != NULL)
            is_drafts = e_mail_folder_uri_equal (
                session, folder_uri, drafts_folder_uri);

        if (is_drafts)
            break;
    }

    g_list_free_full (list, (GDestroyNotify) g_object_unref);
    g_free (folder_uri);

    return is_drafts;
}

/**
 * em_utils_folder_is_templates:
 * @registry: an #ESourceRegistry
 * @folder: a #CamelFolder
 *
 * Decides if @folder is a Templates folder.
 *
 * Returns %TRUE if this is a Templates folder or %FALSE otherwise.
 **/

gboolean
em_utils_folder_is_templates (ESourceRegistry *registry,
                              CamelFolder *folder)
{
    CamelFolder *local_templates_folder;
    CamelSession *session;
    CamelStore *store;
    GList *list, *iter;
    gchar *folder_uri;
    gboolean is_templates = FALSE;
    const gchar *extension_name;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    local_templates_folder =
        e_mail_session_get_local_folder (
        E_MAIL_SESSION (session), E_MAIL_LOCAL_FOLDER_TEMPLATES);

    if (folder == local_templates_folder)
        return TRUE;

    folder_uri = e_mail_folder_uri_from_folder (folder);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    extension_name = E_SOURCE_EXTENSION_MAIL_COMPOSITION;
    list = e_source_registry_list_sources (registry, extension_name);

    for (iter = list; iter != NULL; iter = g_list_next (iter)) {
        ESource *source = E_SOURCE (iter->data);
        ESourceExtension *extension;
        const gchar *templates_folder_uri;

        extension = e_source_get_extension (source, extension_name);

        templates_folder_uri =
            e_source_mail_composition_get_templates_folder (
            E_SOURCE_MAIL_COMPOSITION (extension));

        if (templates_folder_uri != NULL)
            is_templates = e_mail_folder_uri_equal (
                session, folder_uri, templates_folder_uri);

        if (is_templates)
            break;
    }

    g_list_free_full (list, (GDestroyNotify) g_object_unref);
    g_free (folder_uri);

    return is_templates;
}

/**
 * em_utils_folder_is_sent:
 * @registry: an #ESourceRegistry
 * @folder: a #CamelFolder
 *
 * Decides if @folder is a Sent folder.
 *
 * Returns %TRUE if this is a Sent folder or %FALSE otherwise.
 **/
gboolean
em_utils_folder_is_sent (ESourceRegistry *registry,
                         CamelFolder *folder)
{
    CamelFolder *local_sent_folder;
    CamelSession *session;
    CamelStore *store;
    GList *list, *iter;
    gchar *folder_uri;
    gboolean is_sent = FALSE;
    const gchar *extension_name;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    local_sent_folder =
        e_mail_session_get_local_folder (
        E_MAIL_SESSION (session), E_MAIL_LOCAL_FOLDER_SENT);

    if (folder == local_sent_folder)
        return TRUE;

    folder_uri = e_mail_folder_uri_from_folder (folder);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    extension_name = E_SOURCE_EXTENSION_MAIL_SUBMISSION;
    list = e_source_registry_list_sources (registry, extension_name);

    for (iter = list; iter != NULL; iter = g_list_next (iter)) {
        ESource *source = E_SOURCE (iter->data);
        ESourceExtension *extension;
        const gchar *sent_folder_uri;

        extension = e_source_get_extension (source, extension_name);

        sent_folder_uri =
            e_source_mail_submission_get_sent_folder (
            E_SOURCE_MAIL_SUBMISSION (extension));

        if (sent_folder_uri != NULL)
            is_sent = e_mail_folder_uri_equal (
                session, folder_uri, sent_folder_uri);

        if (is_sent)
            break;
    }

    g_list_free_full (list, (GDestroyNotify) g_object_unref);
    g_free (folder_uri);

    return is_sent;
}

/**
 * em_utils_folder_is_outbox:
 * @registry: an #ESourceRegistry
 * @folder: a #CamelFolder
 *
 * Decides if @folder is an Outbox folder.
 *
 * Returns %TRUE if this is an Outbox folder or %FALSE otherwise.
 **/
gboolean
em_utils_folder_is_outbox (ESourceRegistry *registry,
                           CamelFolder *folder)
{
    CamelStore *store;
    CamelSession *session;
    CamelFolder *local_outbox_folder;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);

    store = camel_folder_get_parent_store (folder);
    session = camel_service_get_session (CAMEL_SERVICE (store));

    local_outbox_folder =
        e_mail_session_get_local_folder (
        E_MAIL_SESSION (session), E_MAIL_LOCAL_FOLDER_OUTBOX);

    return (folder == local_outbox_folder);
}

/* ********************************************************************** */

struct TryOpenEBookStruct {
    GError **error;
    EFlag *flag;
    gboolean result;
};

static void
try_open_book_client_cb (GObject *source_object,
                         GAsyncResult *result,
                         gpointer closure)
{
    EBookClient *book_client = E_BOOK_CLIENT (source_object);
    struct TryOpenEBookStruct *data = (struct TryOpenEBookStruct *) closure;
    GError *error = NULL;

    if (!data)
        return;

    e_client_open_finish (E_CLIENT (book_client), result, &error);

    data->result = error == NULL;

    if (!data->result) {
        g_clear_error (data->error);
        g_propagate_error (data->error, error);
    }

    e_flag_set (data->flag);
}

/*
 * try_open_book_client:
 * Tries to open address book asynchronously, but acts as synchronous.
 * The advantage is it checks periodically whether the camel_operation
 * has been canceled or not, and if so, then stops immediately, with
 * result FALSE. Otherwise returns same as e_client_open()
 */
static gboolean
try_open_book_client (EBookClient *book_client,
                      gboolean only_if_exists,
                      GCancellable *cancellable,
                      GError **error)
{
    struct TryOpenEBookStruct data;
    gboolean canceled = FALSE;
    EFlag *flag = e_flag_new ();

    data.error = error;
    data.flag = flag;
    data.result = FALSE;

    e_client_open (
        E_CLIENT (book_client), only_if_exists,
        cancellable, try_open_book_client_cb, &data);

    while (canceled = g_cancellable_is_cancelled (cancellable),
            !canceled && !e_flag_is_set (flag)) {
        GTimeVal wait;

        g_get_current_time (&wait);
        g_time_val_add (&wait, 250000); /* waits 250ms */

        e_flag_timed_wait (flag, &wait);
    }

    if (canceled) {
        g_cancellable_cancel (cancellable);

        g_clear_error (error);
        g_propagate_error (
            error, e_client_error_create (
            E_CLIENT_ERROR_CANCELLED, NULL));
    }

    e_flag_wait (flag);
    e_flag_free (flag);

    return data.result && (!error || !*error);
}

#define NOT_FOUND_BOOK (GINT_TO_POINTER (1))

G_LOCK_DEFINE_STATIC (contact_cache);

/* key is lowercased contact email; value is EBook pointer
 * (just for comparison) where it comes from */
static GHashTable *contact_cache = NULL;

/* key is source ID; value is pointer to EBook */
static GHashTable *emu_books_hash = NULL;

/* key is source ID; value is same pointer as key; this is hash of
 * broken books, which failed to open for some reason */
static GHashTable *emu_broken_books_hash = NULL;

static gboolean
search_address_in_addressbooks (ESourceRegistry *registry,
                                const gchar *address,
                                gboolean local_only,
                                gboolean (*check_contact) (EContact *contact,
                                                           gpointer user_data),
                                gpointer user_data,
                                GCancellable *cancellable)
{
    GList *list, *link;
    GList *addr_sources = NULL;
    gboolean found = FALSE, stop = FALSE, found_any = FALSE;
    gchar *lowercase_addr;
    gpointer ptr;
    EBookQuery *book_query;
    gchar *query;
    const gchar *extension_name;

    if (!address || !*address)
        return FALSE;

    G_LOCK (contact_cache);

    if (emu_books_hash == NULL) {
        emu_books_hash = g_hash_table_new_full (
            g_str_hash, g_str_equal, g_free, g_object_unref);
        emu_broken_books_hash = g_hash_table_new_full (
            g_str_hash, g_str_equal, g_free, NULL);
        contact_cache = g_hash_table_new_full (
            g_str_hash, g_str_equal, g_free, NULL);
    }

    lowercase_addr = g_utf8_strdown (address, -1);
    ptr = g_hash_table_lookup (contact_cache, lowercase_addr);
    if (ptr != NULL && (check_contact == NULL || ptr == NOT_FOUND_BOOK)) {
        g_free (lowercase_addr);
        G_UNLOCK (contact_cache);
        return ptr != NOT_FOUND_BOOK;
    }

    book_query = e_book_query_field_test (E_CONTACT_EMAIL, E_BOOK_QUERY_IS, address);
    query = e_book_query_to_string (book_query);
    e_book_query_unref (book_query);

    extension_name = E_SOURCE_EXTENSION_ADDRESS_BOOK;
    list = e_source_registry_list_sources (registry, extension_name);

    for (link = list; link != NULL; link = g_list_next (link)) {
        ESource *source = E_SOURCE (link->data);
        ESourceExtension *extension;
        const gchar *backend_name;
        gboolean source_is_local;
        gboolean autocomplete;

        extension_name = E_SOURCE_EXTENSION_ADDRESS_BOOK;
        extension = e_source_get_extension (source, extension_name);

        backend_name = e_source_backend_get_backend_name (
            E_SOURCE_BACKEND (extension));

        source_is_local = (g_strcmp0 (backend_name, "local") == 0);

        if (local_only && !source_is_local)
            continue;

        extension_name = E_SOURCE_EXTENSION_AUTOCOMPLETE;
        extension = e_source_get_extension (source, extension_name);

        autocomplete = e_source_autocomplete_get_include_me (
            E_SOURCE_AUTOCOMPLETE (extension));

        if (!autocomplete)
            continue;

        addr_sources = g_list_prepend (
            addr_sources, g_object_ref (source));
    }

    g_list_free_full (list, (GDestroyNotify) g_object_unref);

    for (link = addr_sources; !stop && !found && link != NULL; link = g_list_next (link)) {
        ESource *source = E_SOURCE (link->data);
        GSList *contacts;
        EBookClient *book_client = NULL;
        gboolean cached_book = FALSE;
        const gchar *display_name;
        const gchar *uid;
        GError *err = NULL;

        uid = e_source_get_uid (source);
        display_name = e_source_get_display_name (source);

        /* failed to load this book last time, skip it now */
        if (g_hash_table_lookup (emu_broken_books_hash, uid) != NULL) {
            d(printf ("%s: skipping broken book '%s'\n",
                G_STRFUNC, display_name));
            continue;
        }

        d(printf(" checking '%s'\n", e_source_get_uri(source)));

        book_client = g_hash_table_lookup (emu_books_hash, uid);
        if (!book_client) {
            book_client = e_book_client_new (source, &err);

            if (book_client == NULL) {
                if (err && (g_error_matches (err, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
                    g_error_matches (err, G_IO_ERROR, G_IO_ERROR_CANCELLED))) {
                    stop = TRUE;
                } else if (err) {
                    gchar *source_uid;

                    source_uid = g_strdup (uid);

                    g_hash_table_insert (
                        emu_broken_books_hash,
                        source_uid, source_uid);

                    g_warning (
                        "%s: Unable to create addressbook '%s': %s",
                        G_STRFUNC,
                        display_name,
                        err->message);
                }
                g_clear_error (&err);
            } else if (!stop && !try_open_book_client (book_client, TRUE, cancellable, &err)) {
                g_object_unref (book_client);
                book_client = NULL;

                if (err && (g_error_matches (err, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
                    g_error_matches (err, G_IO_ERROR, G_IO_ERROR_CANCELLED))) {
                    stop = TRUE;
                } else if (err) {
                    gchar *source_uid;

                    source_uid = g_strdup (uid);

                    g_hash_table_insert (
                        emu_broken_books_hash,
                        source_uid, source_uid);

                    g_warning (
                        "%s: Unable to open addressbook '%s': %s",
                        G_STRFUNC,
                        display_name,
                        err->message);
                }
                g_clear_error (&err);
            }
        } else {
            cached_book = TRUE;
        }

        if (book_client && !stop &&
            e_book_client_get_contacts_sync (
            book_client, query, &contacts, cancellable, &err)) {
            if (contacts != NULL) {
                if (!found_any) {
                    g_hash_table_insert (
                        contact_cache,
                        g_strdup (lowercase_addr),
                        book_client);
                }
                found_any = TRUE;

                if (check_contact) {
                    GSList *l;

                    for (l = contacts; l && !found; l = l->next) {
                        EContact *contact = l->data;

                        found = check_contact (contact, user_data);
                    }
                } else {
                    found = TRUE;
                }

                g_slist_foreach (contacts, (GFunc) g_object_unref, NULL);
                g_slist_free (contacts);
            }
        } else if (book_client) {
            stop = stop || (err &&
                (g_error_matches (err, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
                 g_error_matches (err, G_IO_ERROR, G_IO_ERROR_CANCELLED)));
            if (err && !stop) {
                gchar *source_uid = g_strdup (uid);

                g_hash_table_insert (
                    emu_broken_books_hash,
                    source_uid, source_uid);

                g_warning (
                    "%s: Can't get contacts from '%s': %s",
                    G_STRFUNC,
                    display_name,
                    err->message);
            }
            g_clear_error (&err);
        }

        if (stop && !cached_book && book_client) {
            g_object_unref (book_client);
        } else if (!stop && book_client && !cached_book) {
            g_hash_table_insert (
                emu_books_hash, g_strdup (uid), book_client);
        }
    }

    g_list_free_full (addr_sources, (GDestroyNotify) g_object_unref);

    g_free (query);

    if (!found_any) {
        g_hash_table_insert (contact_cache, lowercase_addr, NOT_FOUND_BOOK);
        lowercase_addr = NULL;
    }

    G_UNLOCK (contact_cache);

    g_free (lowercase_addr);

    return found_any;
}

gboolean
em_utils_in_addressbook (ESourceRegistry *registry,
                         CamelInternetAddress *iaddr,
                         gboolean local_only,
                         GCancellable *cancellable)
{
    const gchar *addr;

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), FALSE);

    /* TODO: check all addresses? */
    if (iaddr == NULL || !camel_internet_address_get (iaddr, 0, NULL, &addr))
        return FALSE;

    return search_address_in_addressbooks (
        registry, addr, local_only, NULL, NULL, cancellable);
}

static gboolean
extract_photo_data (EContact *contact,
                    gpointer user_data)
{
    EContactPhoto **photo = user_data;

    g_return_val_if_fail (contact != NULL, FALSE);
    g_return_val_if_fail (user_data != NULL, FALSE);

    *photo = e_contact_get (contact, E_CONTACT_PHOTO);
    if (!*photo)
        *photo = e_contact_get (contact, E_CONTACT_LOGO);

    return *photo != NULL;
}

typedef struct _PhotoInfo {
    gchar *address;
    EContactPhoto *photo;
} PhotoInfo;

static void
emu_free_photo_info (PhotoInfo *pi)
{
    if (!pi)
        return;

    if (pi->address)
        g_free (pi->address);
    if (pi->photo)
        e_contact_photo_free (pi->photo);
    g_free (pi);
}

G_LOCK_DEFINE_STATIC (photos_cache);
static GSList *photos_cache = NULL; /* list of PhotoInfo-s */

CamelMimePart *
em_utils_contact_photo (ESourceRegistry *registry,
                        CamelInternetAddress *cia,
                        gboolean local_only,
                        GCancellable *cancellable)
{
    const gchar *addr = NULL;
    CamelMimePart *part = NULL;
    EContactPhoto *photo = NULL;
    GSList *p, *last = NULL;
    gint cache_len;

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), NULL);

    if (cia == NULL || !camel_internet_address_get (cia, 0, NULL, &addr) || !addr) {
        return NULL;
    }

    G_LOCK (photos_cache);

    /* search a cache first */
    cache_len = 0;
    last = NULL;
    for (p = photos_cache; p; p = p->next) {
        PhotoInfo *pi = p->data;

        if (!pi)
            continue;

        if (g_ascii_strcasecmp (addr, pi->address) == 0) {
            photo = pi->photo;
            break;
        }

        cache_len++;
        last = p;
    }

    /* !p means the address had not been found in the cache */
    if (!p && search_address_in_addressbooks (
        registry, addr, local_only, extract_photo_data, &photo, cancellable)) {

        PhotoInfo *pi;

        /* keep only up to 10 photos in memory */
        if (last && (cache_len >= 10)) {
            pi = last->data;
            photos_cache = g_slist_remove (photos_cache, pi);

            if (pi)
                emu_free_photo_info (pi);
        }

        pi = g_new0 (PhotoInfo, 1);
        pi->address = g_strdup (addr);
        pi->photo = photo;

        photos_cache = g_slist_prepend (photos_cache, pi);
    }

    /* some photo found, use it */
    if (photo) {
        /* Form a mime part out of the photo */
        part = camel_mime_part_new ();

        if (photo->type == E_CONTACT_PHOTO_TYPE_INLINED) {
            camel_mime_part_set_content (part,
                (const gchar *) photo->data.inlined.data,
                photo->data.inlined.length, "image/jpeg");
        } else {
            gchar *s = g_filename_from_uri (photo->data.uri, NULL, NULL);
            camel_mime_part_set_filename (part, s);
            g_free (s);
        }
    }

    G_UNLOCK (photos_cache);

    return part;
}

/* list of email addresses (strings) to remove from local cache of photos and
 * contacts, but only if the photo doesn't exist or is an not-found contact */
void
emu_remove_from_mail_cache (const GSList *addresses)
{
    const GSList *a;
    GSList *p;
    CamelInternetAddress *cia;

    cia = camel_internet_address_new ();

    for (a = addresses; a; a = a->next) {
        const gchar *addr = NULL;

        if (!a->data)
            continue;

        if (camel_address_decode ((CamelAddress *) cia, a->data) != -1 &&
            camel_internet_address_get (cia, 0, NULL, &addr) && addr) {
            gchar *lowercase_addr = g_utf8_strdown (addr, -1);

            G_LOCK (contact_cache);
            if (g_hash_table_lookup (contact_cache, lowercase_addr) == NOT_FOUND_BOOK)
                g_hash_table_remove (contact_cache, lowercase_addr);
            G_UNLOCK (contact_cache);

            g_free (lowercase_addr);

            G_LOCK (photos_cache);
            for (p = photos_cache; p; p = p->next) {
                PhotoInfo *pi = p->data;

                if (pi && !pi->photo && g_ascii_strcasecmp (pi->address, addr) == 0) {
                    photos_cache = g_slist_remove (photos_cache, pi);
                    emu_free_photo_info (pi);
                    break;
                }
            }
            G_UNLOCK (photos_cache);
        }
    }

    g_object_unref (cia);
}

void
emu_remove_from_mail_cache_1 (const gchar *address)
{
    GSList *l;

    g_return_if_fail (address != NULL);

    l = g_slist_append (NULL, (gpointer) address);

    emu_remove_from_mail_cache (l);

    g_slist_free (l);
}

/* frees all data created by call of em_utils_in_addressbook() or
 * em_utils_contact_photo() */
void
emu_free_mail_cache (void)
{
    G_LOCK (contact_cache);

    if (emu_books_hash) {
        g_hash_table_destroy (emu_books_hash);
        emu_books_hash = NULL;
    }

    if (emu_broken_books_hash) {
        g_hash_table_destroy (emu_broken_books_hash);
        emu_broken_books_hash = NULL;
    }

    if (contact_cache) {
        g_hash_table_destroy (contact_cache);
        contact_cache = NULL;
    }

    G_UNLOCK (contact_cache);

    G_LOCK (photos_cache);

    g_slist_foreach (photos_cache, (GFunc) emu_free_photo_info, NULL);
    g_slist_free (photos_cache);
    photos_cache = NULL;

    G_UNLOCK (photos_cache);
}

static ESource *
guess_mail_account_from_folder (ESourceRegistry *registry,
                                CamelFolder *folder)
{
    ESource *source;
    CamelStore *store;
    const gchar *uid;

    /* Lookup an ESource by CamelStore UID. */
    store = camel_folder_get_parent_store (folder);
    uid = camel_service_get_uid (CAMEL_SERVICE (store));
    source = e_source_registry_ref_source (registry, uid);

    /* If we found an ESource, make sure it's a mail account. */
    if (source != NULL) {
        const gchar *extension_name;

        extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
        if (!e_source_has_extension (source, extension_name)) {
            g_object_unref (source);
            source = NULL;
        }
    }

    return source;
}

static ESource *
guess_mail_account_from_message (ESourceRegistry *registry,
                                 CamelMimeMessage *message)
{
    ESource *source = NULL;
    const gchar *uid;

    /* Lookup an ESource by 'X-Evolution-Source' header. */
    uid = camel_mime_message_get_source (message);
    if (uid != NULL)
        source = e_source_registry_ref_source (registry, uid);

    /* If we found an ESource, make sure it's a mail account. */
    if (source != NULL) {
        const gchar *extension_name;

        extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
        if (!e_source_has_extension (source, extension_name)) {
            g_object_unref (source);
            source = NULL;
        }
    }

    return source;
}

ESource *
em_utils_guess_mail_account (ESourceRegistry *registry,
                             CamelMimeMessage *message,
                             CamelFolder *folder)
{
    ESource *source = NULL;
    const gchar *newsgroups;

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), NULL);
    g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), NULL);

    if (folder != NULL)
        g_return_val_if_fail (CAMEL_IS_FOLDER (folder), NULL);

    /* check for newsgroup header */
    newsgroups = camel_medium_get_header (
        CAMEL_MEDIUM (message), "Newsgroups");
    if (folder != NULL && newsgroups != NULL)
        source = guess_mail_account_from_folder (registry, folder);

    /* check for source folder */
    if (source == NULL && folder != NULL)
        source = guess_mail_account_from_folder (registry, folder);

    /* then message source */
    if (source == NULL)
        source = guess_mail_account_from_message (registry, message);

    return source;
}

ESource *
em_utils_guess_mail_identity (ESourceRegistry *registry,
                              CamelMimeMessage *message,
                              CamelFolder *folder)
{
    ESource *source;
    ESourceExtension *extension;
    const gchar *extension_name;
    const gchar *uid;

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), NULL);
    g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), NULL);

    if (folder != NULL)
        g_return_val_if_fail (CAMEL_IS_FOLDER (folder), NULL);

    source = em_utils_guess_mail_account (registry, message, folder);

    if (source == NULL)
        return NULL;

    extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
    extension = e_source_get_extension (source, extension_name);

    uid = e_source_mail_account_get_identity_uid (
        E_SOURCE_MAIL_ACCOUNT (extension));
    if (uid == NULL)
        return NULL;

    source = e_source_registry_ref_source (registry, uid);
    if (source == NULL)
        return NULL;

    extension_name = E_SOURCE_EXTENSION_MAIL_IDENTITY;
    if (!e_source_has_extension (source, extension_name)) {
        g_object_unref (source);
        return NULL;
    }

    return source;
}

static gboolean
mail_account_in_recipients (ESourceRegistry *registry,
                            ESource *source,
                            GHashTable *recipients)
{
    ESourceExtension *extension;
    const gchar *extension_name;
    const gchar *uid;
    gboolean match = FALSE;
    gchar *address;

    /* Disregard disabled mail accounts. */
    if (!e_source_get_enabled (source))
        return FALSE;

    extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
    extension = e_source_get_extension (source, extension_name);

    uid = e_source_mail_account_get_identity_uid (
        E_SOURCE_MAIL_ACCOUNT (extension));
    if (uid == NULL)
        return FALSE;

    source = e_source_registry_ref_source (registry, uid);
    if (source == NULL)
        return FALSE;

    extension_name = E_SOURCE_EXTENSION_MAIL_IDENTITY;
    if (!e_source_has_extension (source, extension_name)) {
        g_object_unref (source);
        return FALSE;
    }

    extension = e_source_get_extension (source, extension_name);

    address = e_source_mail_identity_dup_address (
        E_SOURCE_MAIL_IDENTITY (extension));

    g_object_unref (source);

    if (address != NULL) {
        match = (g_hash_table_lookup (recipients, address) != NULL);
        g_free (address);
    }

    return match;
}

ESource *
em_utils_guess_mail_account_with_recipients (ESourceRegistry *registry,
                                             CamelMimeMessage *message,
                                             CamelFolder *folder)
{
    ESource *source = NULL;
    GHashTable *recipients;
    CamelInternetAddress *addr;
    GList *list, *iter;
    const gchar *extension_name;
    const gchar *type;
    const gchar *key;

    /* This policy is subject to debate and tweaking,
     * but please also document the rational here. */

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), NULL);
    g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), NULL);

    /* Build a set of email addresses in which to test for membership.
     * Only the keys matter here; the values just need to be non-NULL. */
    recipients = g_hash_table_new (g_str_hash, g_str_equal);

    type = CAMEL_RECIPIENT_TYPE_TO;
    addr = camel_mime_message_get_recipients (message, type);
    if (addr != NULL) {
        gint index = 0;

        while (camel_internet_address_get (addr, index++, NULL, &key))
            g_hash_table_insert (
                recipients, (gpointer) key,
                GINT_TO_POINTER (1));
    }

    type = CAMEL_RECIPIENT_TYPE_CC;
    addr = camel_mime_message_get_recipients (message, type);
    if (addr != NULL) {
        gint index = 0;

        while (camel_internet_address_get (addr, index++, NULL, &key))
            g_hash_table_insert (
                recipients, (gpointer) key,
                GINT_TO_POINTER (1));
    }

    /* First Preference: We were given a folder that maps to an
     * enabled mail account, and that account's address appears
     * in the list of To: or Cc: recipients. */

    if (folder != NULL)
        source = guess_mail_account_from_folder (registry, folder);

    if (source == NULL)
        goto second_preference;

    if (mail_account_in_recipients (registry, source, recipients))
        goto exit;

second_preference:

    /* Second Preference: Choose any enabled mail account whose
     * address appears in the list to To: or Cc: recipients. */

    if (source != NULL) {
        g_object_unref (source);
        source = NULL;
    }

    extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
    list = e_source_registry_list_sources (registry, extension_name);

    for (iter = list; iter != NULL; iter = g_list_next (iter)) {
        ESource *temp = E_SOURCE (iter->data);

        if (mail_account_in_recipients (registry, temp, recipients)) {
            source = g_object_ref (temp);
            break;
        }
    }

    g_list_free_full (list, (GDestroyNotify) g_object_unref);

    if (source != NULL)
        goto exit;

    /* Last Preference: Defer to em_utils_guess_mail_account(). */
    source = em_utils_guess_mail_account (registry, message, folder);

exit:
    g_hash_table_destroy (recipients);

    return source;
}

ESource *
em_utils_guess_mail_identity_with_recipients (ESourceRegistry *registry,
                                              CamelMimeMessage *message,
                                              CamelFolder *folder)
{
    ESource *source;
    ESourceExtension *extension;
    const gchar *extension_name;
    const gchar *uid;

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), NULL);
    g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), NULL);

    source = em_utils_guess_mail_account_with_recipients (
        registry, message, folder);

    if (source == NULL)
        return NULL;

    extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
    extension = e_source_get_extension (source, extension_name);

    uid = e_source_mail_account_get_identity_uid (
        E_SOURCE_MAIL_ACCOUNT (extension));
    if (uid == NULL)
        return NULL;

    source = e_source_registry_ref_source (registry, uid);
    if (source == NULL)
        return NULL;

    extension_name = E_SOURCE_EXTENSION_MAIL_IDENTITY;
    if (!e_source_has_extension (source, extension_name)) {
        g_object_unref (source);
        return NULL;
    }

    return source;
}

ESource *
em_utils_ref_mail_identity_for_store (ESourceRegistry *registry,
                                      CamelStore *store)
{
    ESourceMailAccount *extension;
    ESource *source;
    const gchar *extension_name;
    const gchar *store_uid;
    gchar *identity_uid;

    g_return_val_if_fail (E_IS_SOURCE_REGISTRY (registry), NULL);
    g_return_val_if_fail (CAMEL_IS_STORE (store), NULL);

    store_uid = camel_service_get_uid (CAMEL_SERVICE (store));
    g_return_val_if_fail (store_uid != NULL, NULL);

    source = e_source_registry_ref_source (registry, store_uid);
    g_return_val_if_fail (source != NULL, NULL);

    extension_name = E_SOURCE_EXTENSION_MAIL_ACCOUNT;
    extension = e_source_get_extension (source, extension_name);
    identity_uid = e_source_mail_account_dup_identity_uid (extension);

    g_object_unref (source);
    source = NULL;

    if (identity_uid != NULL) {
        source = e_source_registry_ref_source (registry, identity_uid);
        g_free (identity_uid);
    }

    return source;
}

/**
 * em_utils_uids_free:
 * @uids: array of uids
 *
 * Frees the array of uids pointed to by @uids back to the system.
 **/
void
em_utils_uids_free (GPtrArray *uids)
{
    gint i;

    for (i = 0; i < uids->len; i++)
        g_free (uids->pdata[i]);

    g_ptr_array_free (uids, TRUE);
}

/* Returns TRUE if CamelURL points to a local mbox file. */
gboolean
em_utils_is_local_delivery_mbox_file (CamelURL *url)
{
    g_return_val_if_fail (url != NULL, FALSE);

    return g_str_equal (url->protocol, "mbox") &&
        (url->path != NULL) &&
        g_file_test (url->path, G_FILE_TEST_EXISTS) &&
        !g_file_test (url->path, G_FILE_TEST_IS_DIR);
}