path: root/libemail-engine/e-mail-folder-utils.c

/*
 * e-mail-folder-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/>
 *
 */

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

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

#include <glib/gi18n-lib.h>

#include <libedataserver/libedataserver.h>

#include <libemail-engine/e-mail-session.h>
#include <libemail-engine/mail-tools.h>

#include "e-mail-utils.h"

/* X-Mailer header value */
#define X_MAILER ("Evolution " VERSION SUB_VERSION " " VERSION_COMMENT)

typedef struct _AsyncContext AsyncContext;

struct _AsyncContext {
    CamelMimeMessage *message;
    CamelMessageInfo *info;
    CamelMimePart *part;
    GHashTable *hash_table;
    GPtrArray *ptr_array;
    GFile *destination;
    gchar *fwd_subject;
    gchar *message_uid;
};

static void
async_context_free (AsyncContext *context)
{
    if (context->message != NULL)
        g_object_unref (context->message);

    if (context->info != NULL)
        camel_message_info_unref (context->info);

    if (context->part != NULL)
        g_object_unref (context->part);

    if (context->hash_table != NULL)
        g_hash_table_unref (context->hash_table);

    if (context->ptr_array != NULL)
        g_ptr_array_unref (context->ptr_array);

    if (context->destination != NULL)
        g_object_unref (context->destination);

    g_free (context->fwd_subject);
    g_free (context->message_uid);

    g_slice_free (AsyncContext, context);
}

static void
mail_folder_append_message_thread (GSimpleAsyncResult *simple,
                                   GObject *object,
                                   GCancellable *cancellable)
{
    AsyncContext *context;
    GError *error = NULL;

    context = g_simple_async_result_get_op_res_gpointer (simple);

    e_mail_folder_append_message_sync (
        CAMEL_FOLDER (object), context->message,
        context->info, &context->message_uid,
        cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

gboolean
e_mail_folder_append_message_sync (CamelFolder *folder,
                                   CamelMimeMessage *message,
                                   CamelMessageInfo *info,
                                   gchar **appended_uid,
                                   GCancellable *cancellable,
                                   GError **error)
{
    CamelMedium *medium;
    gboolean success;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);
    g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), FALSE);

    medium = CAMEL_MEDIUM (message);

    camel_operation_push_message (
        cancellable,
        _("Saving message to folder '%s'"),
        camel_folder_get_display_name (folder));

    if (camel_medium_get_header (medium, "X-Mailer") == NULL)
        camel_medium_set_header (medium, "X-Mailer", X_MAILER);

    camel_mime_message_set_date (message, CAMEL_MESSAGE_DATE_CURRENT, 0);

    success = camel_folder_append_message_sync (
        folder, message, info, appended_uid, cancellable, error);

    camel_operation_pop_message (cancellable);

    return success;
}

void
e_mail_folder_append_message (CamelFolder *folder,
                              CamelMimeMessage *message,
                              CamelMessageInfo *info,
                              gint io_priority,
                              GCancellable *cancellable,
                              GAsyncReadyCallback callback,
                              gpointer user_data)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));
    g_return_if_fail (CAMEL_IS_MIME_MESSAGE (message));

    context = g_slice_new0 (AsyncContext);
    context->message = g_object_ref (message);

    if (info != NULL)
        context->info = camel_message_info_ref (info);

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback, user_data,
        e_mail_folder_append_message);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_set_op_res_gpointer (
        simple, context, (GDestroyNotify) async_context_free);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_append_message_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

gboolean
e_mail_folder_append_message_finish (CamelFolder *folder,
                                     GAsyncResult *result,
                                     gchar **appended_uid,
                                     GError **error)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_append_message), FALSE);

    simple = G_SIMPLE_ASYNC_RESULT (result);
    context = g_simple_async_result_get_op_res_gpointer (simple);

    if (appended_uid != NULL) {
        *appended_uid = context->message_uid;
        context->message_uid = NULL;
    }

    /* Assume success unless a GError is set. */
    return !g_simple_async_result_propagate_error (simple, error);
}

static void
mail_folder_expunge_thread (GSimpleAsyncResult *simple,
                            GObject *object,
                            GCancellable *cancellable)
{
    GError *error = NULL;

    e_mail_folder_expunge_sync (
        CAMEL_FOLDER (object), cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

static gboolean
mail_folder_expunge_pop3_stores (CamelFolder *folder,
                                 GCancellable *cancellable,
                                 GError **error)
{
    GHashTable *expunging_uids;
    CamelStore *parent_store;
    CamelService *service;
    CamelSession *session;
    ESourceRegistry *registry;
    GPtrArray *uids;
    GList *list, *link;
    const gchar *extension_name;
    gboolean success = TRUE;
    guint ii;

    parent_store = camel_folder_get_parent_store (folder);

    service = CAMEL_SERVICE (parent_store);
    session = camel_service_ref_session (service);
    registry = e_mail_session_get_registry (E_MAIL_SESSION (session));

    uids = camel_folder_get_uids (folder);

    if (uids == NULL)
        goto exit;

    expunging_uids = g_hash_table_new_full (
        (GHashFunc) g_str_hash,
        (GEqualFunc) g_str_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) g_free);

    for (ii = 0; ii < uids->len; ii++) {
        CamelMessageInfo *info;
        CamelMessageFlags flags = 0;
        CamelMimeMessage *message;
        const gchar *pop3_uid;
        const gchar *source_uid;

        info = camel_folder_get_message_info (
            folder, uids->pdata[ii]);

        if (info != NULL) {
            flags = camel_message_info_flags (info);
            camel_message_info_unref (info);
        }

        /* Only interested in deleted messages. */
        if ((flags & CAMEL_MESSAGE_DELETED) == 0)
            continue;

        /* because the UID in the local store doesn't
         * match with the UID in the pop3 store */
        message = camel_folder_get_message_sync (
            folder, uids->pdata[ii], cancellable, NULL);

        if (message == NULL)
            continue;

        pop3_uid = camel_medium_get_header (
            CAMEL_MEDIUM (message), "X-Evolution-POP3-UID");
        source_uid = camel_mime_message_get_source (message);

        if (pop3_uid != NULL)
            g_hash_table_insert (
                expunging_uids,
                g_strstrip (g_strdup (pop3_uid)),
                g_strstrip (g_strdup (source_uid)));

        g_object_unref (message);
    }

    camel_folder_free_uids (folder, uids);
    uids = NULL;

    if (g_hash_table_size (expunging_uids) == 0) {
        g_hash_table_destroy (expunging_uids);
        return TRUE;
    }

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

    for (link = list; link != NULL; link = g_list_next (link)) {
        ESource *source = E_SOURCE (link->data);
        ESourceBackend *extension;
        CamelFolder *folder;
        CamelService *service;
        CamelSettings *settings;
        const gchar *backend_name;
        const gchar *service_uid;
        const gchar *source_uid;
        gboolean any_found = FALSE;
        gboolean delete_expunged = FALSE;
        gboolean keep_on_server = FALSE;

        source_uid = e_source_get_uid (source);

        extension = e_source_get_extension (source, extension_name);
        backend_name = e_source_backend_get_backend_name (extension);

        if (g_strcmp0 (backend_name, "pop") != 0)
            continue;

        service = camel_session_ref_service (
            CAMEL_SESSION (session), source_uid);

        service_uid = camel_service_get_uid (service);
        settings = camel_service_ref_settings (service);

        g_object_get (
            settings,
            "delete-expunged", &delete_expunged,
            "keep-on-server", &keep_on_server,
            NULL);

        g_object_unref (settings);

        if (!keep_on_server || !delete_expunged) {
            g_object_unref (service);
            continue;
        }

        folder = camel_store_get_inbox_folder_sync (
            CAMEL_STORE (service), cancellable, error);

        /* Abort the loop on error. */
        if (folder == NULL) {
            g_object_unref (service);
            success = FALSE;
            break;
        }

        uids = camel_folder_get_uids (folder);

        if (uids == NULL) {
            g_object_unref (service);
            g_object_unref (folder);
            continue;
        }

        for (ii = 0; ii < uids->len; ii++) {
            const gchar *source_uid;

            source_uid = g_hash_table_lookup (
                expunging_uids, uids->pdata[ii]);
            if (g_strcmp0 (source_uid, service_uid) == 0) {
                any_found = TRUE;
                camel_folder_delete_message (
                    folder, uids->pdata[ii]);
            }
        }

        camel_folder_free_uids (folder, uids);

        if (any_found)
            success = camel_folder_synchronize_sync (
                folder, TRUE, cancellable, error);

        g_object_unref (folder);
        g_object_unref (service);

        /* Abort the loop on error. */
        if (!success)
            break;
    }

    g_list_free_full (list, (GDestroyNotify) g_object_unref);

    g_hash_table_destroy (expunging_uids);

exit:
    g_object_unref (session);

    return success;
}

gboolean
e_mail_folder_expunge_sync (CamelFolder *folder,
                            GCancellable *cancellable,
                            GError **error)
{
    CamelFolder *local_inbox;
    CamelStore *parent_store;
    CamelService *service;
    CamelSession *session;
    gboolean is_local_inbox;
    gboolean is_local_trash;
    gboolean store_is_local;
    gboolean success = TRUE;
    const gchar *uid;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);

    parent_store = camel_folder_get_parent_store (folder);

    service = CAMEL_SERVICE (parent_store);
    session = camel_service_ref_session (service);

    uid = camel_service_get_uid (service);
    store_is_local = (g_strcmp0 (uid, E_MAIL_SESSION_LOCAL_UID) == 0);

    local_inbox = e_mail_session_get_local_folder (
        E_MAIL_SESSION (session), E_MAIL_LOCAL_FOLDER_INBOX);
    is_local_inbox = (folder == local_inbox);
    is_local_trash = FALSE;

    if (store_is_local && !is_local_inbox) {
        CamelFolder *local_trash;

        local_trash = camel_store_get_trash_folder_sync (
            parent_store, cancellable, error);

        if (local_trash != NULL) {
            is_local_trash = (folder == local_trash);
            g_object_unref (local_trash);
        } else {
            success = FALSE;
            goto exit;
        }
    }

    /* Expunge all POP3 accounts when expunging
     * the local Inbox or Trash folder. */
    if (is_local_inbox || is_local_trash)
        success = mail_folder_expunge_pop3_stores (
            folder, cancellable, error);

    if (success)
        success = camel_folder_expunge_sync (
            folder, cancellable, error);

exit:
    g_object_unref (session);

    return success;
}

void
e_mail_folder_expunge (CamelFolder *folder,
                       gint io_priority,
                       GCancellable *cancellable,
                       GAsyncReadyCallback callback,
                       gpointer user_data)
{
    GSimpleAsyncResult *simple;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback,
        user_data, e_mail_folder_expunge);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_expunge_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

gboolean
e_mail_folder_expunge_finish (CamelFolder *folder,
                              GAsyncResult *result,
                              GError **error)
{
    GSimpleAsyncResult *simple;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_expunge), FALSE);

    simple = G_SIMPLE_ASYNC_RESULT (result);

    /* Assume success unless a GError is set. */
    return !g_simple_async_result_propagate_error (simple, error);
}

static void
mail_folder_build_attachment_thread (GSimpleAsyncResult *simple,
                                     GObject *object,
                                     GCancellable *cancellable)
{
    AsyncContext *context;
    GError *error = NULL;

    context = g_simple_async_result_get_op_res_gpointer (simple);

    context->part = e_mail_folder_build_attachment_sync (
        CAMEL_FOLDER (object), context->ptr_array,
        &context->fwd_subject, cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

CamelMimePart *
e_mail_folder_build_attachment_sync (CamelFolder *folder,
                                     GPtrArray *message_uids,
                                     gchar **fwd_subject,
                                     GCancellable *cancellable,
                                     GError **error)
{
    GHashTable *hash_table;
    CamelMimeMessage *message;
    CamelMimePart *part;
    const gchar *uid;

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

    /* Need at least one message UID to make an attachment. */
    g_return_val_if_fail (message_uids->len > 0, NULL);

    hash_table = e_mail_folder_get_multiple_messages_sync (
        folder, message_uids, cancellable, error);

    if (hash_table == NULL)
        return NULL;

    /* Create the forward subject from the first message. */

    uid = g_ptr_array_index (message_uids, 0);
    g_return_val_if_fail (uid != NULL, NULL);

    message = g_hash_table_lookup (hash_table, uid);
    g_return_val_if_fail (message != NULL, NULL);

    if (fwd_subject != NULL)
        *fwd_subject = mail_tool_generate_forward_subject (message);

    if (message_uids->len == 1) {
        part = mail_tool_make_message_attachment (message);

    } else {
        CamelMultipart *multipart;
        guint ii;

        multipart = camel_multipart_new ();
        camel_data_wrapper_set_mime_type (
            CAMEL_DATA_WRAPPER (multipart), "multipart/digest");
        camel_multipart_set_boundary (multipart, NULL);

        for (ii = 0; ii < message_uids->len; ii++) {
            uid = g_ptr_array_index (message_uids, ii);
            g_return_val_if_fail (uid != NULL, NULL);

            message = g_hash_table_lookup (hash_table, uid);
            g_return_val_if_fail (message != NULL, NULL);

            part = mail_tool_make_message_attachment (message);
            camel_multipart_add_part (multipart, part);
            g_object_unref (part);
        }

        part = camel_mime_part_new ();

        camel_medium_set_content (
            CAMEL_MEDIUM (part),
            CAMEL_DATA_WRAPPER (multipart));

        camel_mime_part_set_description (
            part, _("Forwarded messages"));

        g_object_unref (multipart);
    }

    g_hash_table_unref (hash_table);

    return part;
}

void
e_mail_folder_build_attachment (CamelFolder *folder,
                                GPtrArray *message_uids,
                                gint io_priority,
                                GCancellable *cancellable,
                                GAsyncReadyCallback callback,
                                gpointer user_data)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));
    g_return_if_fail (message_uids != NULL);

    /* Need at least one message UID to make an attachment. */
    g_return_if_fail (message_uids->len > 0);

    context = g_slice_new0 (AsyncContext);
    context->ptr_array = g_ptr_array_ref (message_uids);

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback, user_data,
        e_mail_folder_build_attachment);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_set_op_res_gpointer (
        simple, context, (GDestroyNotify) async_context_free);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_build_attachment_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

CamelMimePart *
e_mail_folder_build_attachment_finish (CamelFolder *folder,
                                       GAsyncResult *result,
                                       gchar **fwd_subject,
                                       GError **error)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_build_attachment), NULL);

    simple = G_SIMPLE_ASYNC_RESULT (result);
    context = g_simple_async_result_get_op_res_gpointer (simple);

    if (g_simple_async_result_propagate_error (simple, error))
        return NULL;

    if (fwd_subject != NULL) {
        *fwd_subject = context->fwd_subject;
        context->fwd_subject = NULL;
    }

    g_return_val_if_fail (CAMEL_IS_MIME_PART (context->part), NULL);

    return g_object_ref (context->part);
}

static void
mail_folder_find_duplicate_messages_thread (GSimpleAsyncResult *simple,
                                            GObject *object,
                                            GCancellable *cancellable)
{
    AsyncContext *context;
    GError *error = NULL;

    context = g_simple_async_result_get_op_res_gpointer (simple);

    context->hash_table = e_mail_folder_find_duplicate_messages_sync (
        CAMEL_FOLDER (object), context->ptr_array,
        cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

static GHashTable *
emfu_get_messages_hash_sync (CamelFolder *folder,
                             GPtrArray *message_uids,
                             GCancellable *cancellable,
                             GError **error)
{
    GHashTable *hash_table;
    CamelMimeMessage *message;
    guint ii;

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

    camel_operation_push_message (
        cancellable,
        ngettext (
            "Retrieving %d message",
            "Retrieving %d messages",
            message_uids->len),
        message_uids->len);

    hash_table = g_hash_table_new_full (
        (GHashFunc) g_str_hash,
        (GEqualFunc) g_str_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) g_free);

    /* This is an all or nothing operation.  Destroy the
     * hash table if we fail to retrieve any message. */

    for (ii = 0; ii < message_uids->len; ii++) {
        const gchar *uid;
        gint percent;

        uid = g_ptr_array_index (message_uids, ii);
        percent = ((ii + 1) * 100) / message_uids->len;

        message = camel_folder_get_message_sync (
            folder, uid, cancellable, error);

        camel_operation_progress (cancellable, percent);

        if (CAMEL_IS_MIME_MESSAGE (message)) {
            CamelDataWrapper *content;
            gchar *digest = NULL;

            /* Generate a digest string from the message's content. */
            content = camel_medium_get_content (CAMEL_MEDIUM (message));

            if (content != NULL) {
                CamelStream *stream;
                GByteArray *buffer;
                gssize n_bytes;

                stream = camel_stream_mem_new ();

                n_bytes = camel_data_wrapper_decode_to_stream_sync (
                    content, stream, cancellable, error);

                if (n_bytes >= 0) {
                    /* The CamelStreamMem owns the buffer. */
                    buffer = camel_stream_mem_get_byte_array (
                        CAMEL_STREAM_MEM (stream));
                    g_return_val_if_fail (buffer != NULL, NULL);

                    digest = g_compute_checksum_for_data (
                        G_CHECKSUM_SHA256, buffer->data, buffer->len);
                }

                g_object_unref (stream);
            }

            g_hash_table_insert (
                hash_table, g_strdup (uid), digest);
            g_object_unref (message);
        } else {
            g_hash_table_destroy (hash_table);
            hash_table = NULL;
            break;
        }
    }

    camel_operation_pop_message (cancellable);

    return hash_table;
}

GHashTable *
e_mail_folder_find_duplicate_messages_sync (CamelFolder *folder,
                                            GPtrArray *message_uids,
                                            GCancellable *cancellable,
                                            GError **error)
{
    GQueue trash = G_QUEUE_INIT;
    GHashTable *hash_table;
    GHashTable *unique_ids;
    GHashTableIter iter;
    gpointer key, value;

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

    /* hash_table = { MessageUID : digest-as-string } */
    hash_table = emfu_get_messages_hash_sync (
        folder, message_uids, cancellable, error);

    if (hash_table == NULL)
        return NULL;

    camel_operation_push_message (
        cancellable, _("Scanning messages for duplicates"));

    unique_ids = g_hash_table_new_full (
        (GHashFunc) g_int64_hash,
        (GEqualFunc) g_int64_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) g_free);

    g_hash_table_iter_init (&iter, hash_table);

    while (g_hash_table_iter_next (&iter, &key, &value)) {
        const CamelSummaryMessageID *message_id;
        CamelMessageFlags flags;
        CamelMessageInfo *info;
        gboolean duplicate;
        const gchar *digest;

        info = camel_folder_get_message_info (folder, key);
        message_id = camel_message_info_message_id (info);
        flags = camel_message_info_flags (info);

        /* Skip messages marked for deletion. */
        if (flags & CAMEL_MESSAGE_DELETED) {
            g_queue_push_tail (&trash, key);
            camel_message_info_unref (info);
            continue;
        }

        digest = value;

        if (digest == NULL) {
            g_queue_push_tail (&trash, key);
            camel_message_info_unref (info);
            continue;
        }

        /* Determine if the message a duplicate. */

        value = g_hash_table_lookup (unique_ids, &message_id->id.id);
        duplicate = (value != NULL) && g_str_equal (digest, value);

        if (!duplicate) {
            gint64 *v_int64;

            /* XXX Might be better to create a GArray
             *     of 64-bit integers and have the hash
             *     table keys point to array elements. */
            v_int64 = g_new0 (gint64, 1);
            *v_int64 = (gint64) message_id->id.id;

            g_hash_table_insert (unique_ids, v_int64, g_strdup (digest));
            g_queue_push_tail (&trash, key);
        }

        camel_message_info_unref (info);
    }

    /* Delete all non-duplicate messages from the hash table. */
    while ((key = g_queue_pop_head (&trash)) != NULL)
        g_hash_table_remove (hash_table, key);

    camel_operation_pop_message (cancellable);

    g_hash_table_destroy (unique_ids);

    return hash_table;
}

void
e_mail_folder_find_duplicate_messages (CamelFolder *folder,
                                       GPtrArray *message_uids,
                                       gint io_priority,
                                       GCancellable *cancellable,
                                       GAsyncReadyCallback callback,
                                       gpointer user_data)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));
    g_return_if_fail (message_uids != NULL);

    context = g_slice_new0 (AsyncContext);
    context->ptr_array = g_ptr_array_ref (message_uids);

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback, user_data,
        e_mail_folder_find_duplicate_messages);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_set_op_res_gpointer (
        simple, context, (GDestroyNotify) async_context_free);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_find_duplicate_messages_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

GHashTable *
e_mail_folder_find_duplicate_messages_finish (CamelFolder *folder,
                                              GAsyncResult *result,
                                              GError **error)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_find_duplicate_messages), NULL);

    simple = G_SIMPLE_ASYNC_RESULT (result);
    context = g_simple_async_result_get_op_res_gpointer (simple);

    if (g_simple_async_result_propagate_error (simple, error))
        return NULL;

    return g_hash_table_ref (context->hash_table);
}

static void
mail_folder_get_multiple_messages_thread (GSimpleAsyncResult *simple,
                                          GObject *object,
                                          GCancellable *cancellable)
{
    AsyncContext *context;
    GError *error = NULL;

    context = g_simple_async_result_get_op_res_gpointer (simple);

    context->hash_table = e_mail_folder_get_multiple_messages_sync (
        CAMEL_FOLDER (object), context->ptr_array,
        cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

GHashTable *
e_mail_folder_get_multiple_messages_sync (CamelFolder *folder,
                                          GPtrArray *message_uids,
                                          GCancellable *cancellable,
                                          GError **error)
{
    GHashTable *hash_table;
    CamelMimeMessage *message;
    guint ii;

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

    camel_operation_push_message (
        cancellable,
        ngettext (
            "Retrieving %d message",
            "Retrieving %d messages",
            message_uids->len),
        message_uids->len);

    hash_table = g_hash_table_new_full (
        (GHashFunc) g_str_hash,
        (GEqualFunc) g_str_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) g_object_unref);

    /* This is an all or nothing operation.  Destroy the
     * hash table if we fail to retrieve any message. */

    for (ii = 0; ii < message_uids->len; ii++) {
        const gchar *uid;
        gint percent;

        uid = g_ptr_array_index (message_uids, ii);
        percent = ((ii + 1) * 100) / message_uids->len;

        message = camel_folder_get_message_sync (
            folder, uid, cancellable, error);

        camel_operation_progress (cancellable, percent);

        if (CAMEL_IS_MIME_MESSAGE (message)) {
            g_hash_table_insert (
                hash_table, g_strdup (uid), message);
        } else {
            g_hash_table_destroy (hash_table);
            hash_table = NULL;
            break;
        }
    }

    camel_operation_pop_message (cancellable);

    return hash_table;
}

void
e_mail_folder_get_multiple_messages (CamelFolder *folder,
                                     GPtrArray *message_uids,
                                     gint io_priority,
                                     GCancellable *cancellable,
                                     GAsyncReadyCallback callback,
                                     gpointer user_data)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));
    g_return_if_fail (message_uids != NULL);

    context = g_slice_new0 (AsyncContext);
    context->ptr_array = g_ptr_array_ref (message_uids);

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback, user_data,
        e_mail_folder_get_multiple_messages);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_set_op_res_gpointer (
        simple, context, (GDestroyNotify) async_context_free);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_get_multiple_messages_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

GHashTable *
e_mail_folder_get_multiple_messages_finish (CamelFolder *folder,
                                            GAsyncResult *result,
                                            GError **error)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_get_multiple_messages), NULL);

    simple = G_SIMPLE_ASYNC_RESULT (result);
    context = g_simple_async_result_get_op_res_gpointer (simple);

    if (g_simple_async_result_propagate_error (simple, error))
        return NULL;

    return g_hash_table_ref (context->hash_table);
}

static void
mail_folder_remove_thread (GSimpleAsyncResult *simple,
                           GObject *object,
                           GCancellable *cancellable)
{
    GError *error = NULL;

    e_mail_folder_remove_sync (
        CAMEL_FOLDER (object), cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

static gboolean
mail_folder_remove_recursive (CamelStore *store,
                              CamelFolderInfo *folder_info,
                              GCancellable *cancellable,
                              GError **error)
{
    gboolean success = TRUE;

    while (folder_info != NULL) {
        CamelFolder *folder;

        if (folder_info->child != NULL) {
            success = mail_folder_remove_recursive (
                store, folder_info->child, cancellable, error);
            if (!success)
                break;
        }

        folder = camel_store_get_folder_sync (
            store, folder_info->full_name, 0, cancellable, error);
        if (folder == NULL) {
            success = FALSE;
            break;
        }

        if (!CAMEL_IS_VEE_FOLDER (folder)) {
            GPtrArray *uids;
            guint ii;

            /* Delete every message in this folder,
             * then expunge it. */

            camel_folder_freeze (folder);

            uids = camel_folder_get_uids (folder);

            for (ii = 0; ii < uids->len; ii++)
                camel_folder_delete_message (
                    folder, uids->pdata[ii]);

            camel_folder_free_uids (folder, uids);

            success = camel_folder_synchronize_sync (
                folder, TRUE, cancellable, error);

            camel_folder_thaw (folder);
        }

        g_object_unref (folder);

        if (!success)
            break;

        /* If the store supports subscriptions,
         * then unsubscribe from this folder. */
        if (CAMEL_IS_SUBSCRIBABLE (store)) {
            success = camel_subscribable_unsubscribe_folder_sync (
                CAMEL_SUBSCRIBABLE (store),
                folder_info->full_name,
                cancellable, error);
            if (!success)
                break;
        }

        success = camel_store_delete_folder_sync (
            store, folder_info->full_name, cancellable, error);
        if (!success)
            break;

        folder_info = folder_info->next;
    }

    return success;
}

static void
follow_cancel_cb (GCancellable *cancellable,
                  GCancellable *transparent_cancellable)
{
    g_cancellable_cancel (transparent_cancellable);
}

gboolean
e_mail_folder_remove_sync (CamelFolder *folder,
                           GCancellable *cancellable,
                           GError **error)
{
    CamelFolderInfo *folder_info;
    CamelFolderInfo *to_remove;
    CamelFolderInfo *next = NULL;
    CamelStore *parent_store;
    const gchar *display_name;
    const gchar *full_name;
    const gchar *message;
    gboolean success = TRUE;
    GCancellable *transparent_cancellable = NULL;
    gulong cbid = 0;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);

    full_name = camel_folder_get_full_name (folder);
    parent_store = camel_folder_get_parent_store (folder);

    folder_info = camel_store_get_folder_info_sync (
        parent_store, full_name,
        CAMEL_STORE_FOLDER_INFO_FAST |
        CAMEL_STORE_FOLDER_INFO_RECURSIVE |
        CAMEL_STORE_FOLDER_INFO_SUBSCRIBED,
        cancellable, error);

    if (folder_info == NULL)
        return FALSE;

    to_remove = folder_info;

    /* For cases when the top-level folder_info contains siblings,
     * such as when full_name contains a wildcard letter, compare
     * the folder name against folder_info->full_name to avoid
     * removing more folders than requested. */
    if (folder_info->next != NULL) {
        while (to_remove != NULL) {
            if (g_strcmp0 (to_remove->full_name, full_name) == 0)
                break;
            to_remove = to_remove->next;
        }

        /* XXX Should we set a GError and return FALSE here? */
        if (to_remove == NULL) {
            g_warning (
                "%s: Failed to find folder '%s'",
                G_STRFUNC, full_name);
            camel_folder_info_free (folder_info);
            return TRUE;
        }

        /* Prevent iterating over siblings. */
        next = to_remove->next;
        to_remove->next = NULL;
    }

    message = _("Removing folder '%s'");
    display_name = camel_folder_get_display_name (folder);
    camel_operation_push_message (cancellable, message, display_name);

    if (cancellable) {
        transparent_cancellable = g_cancellable_new ();
        cbid = g_cancellable_connect (
            cancellable, G_CALLBACK (follow_cancel_cb),
            transparent_cancellable, NULL);
    }

    success = mail_folder_remove_recursive (
        parent_store, to_remove, transparent_cancellable, error);

    if (transparent_cancellable) {
        g_cancellable_disconnect (cancellable, cbid);
        g_object_unref (transparent_cancellable);
    }

    camel_operation_pop_message (cancellable);

    /* Restore the folder_info tree to its original
     * state so we don't leak folder_info nodes. */
    to_remove->next = next;

    camel_folder_info_free (folder_info);

    return success;
}

void
e_mail_folder_remove (CamelFolder *folder,
                      gint io_priority,
                      GCancellable *cancellable,
                      GAsyncReadyCallback callback,
                      gpointer user_data)
{
    GSimpleAsyncResult *simple;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback,
        user_data, e_mail_folder_remove);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_remove_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

gboolean
e_mail_folder_remove_finish (CamelFolder *folder,
                             GAsyncResult *result,
                             GError **error)
{
    GSimpleAsyncResult *simple;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_remove), FALSE);

    simple = G_SIMPLE_ASYNC_RESULT (result);

    /* Assume success unless a GError is set. */
    return !g_simple_async_result_propagate_error (simple, error);
}

static void
mail_folder_remove_attachments_thread (GSimpleAsyncResult *simple,
                                       GObject *object,
                                       GCancellable *cancellable)
{
    AsyncContext *context;
    GError *error = NULL;

    context = g_simple_async_result_get_op_res_gpointer (simple);

    e_mail_folder_remove_attachments_sync (
        CAMEL_FOLDER (object), context->ptr_array,
        cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

/* Helper for e_mail_folder_remove_attachments_sync() */
static gboolean
mail_folder_strip_message (CamelFolder *folder,
                           CamelMimeMessage *message,
                           const gchar *message_uid,
                           GCancellable *cancellable,
                           GError **error)
{
    CamelDataWrapper *content;
    CamelMultipart *multipart;
    gboolean modified = FALSE;
    gboolean success = TRUE;
    guint ii, n_parts;

    content = camel_medium_get_content (CAMEL_MEDIUM (message));

    if (!CAMEL_IS_MULTIPART (content))
        return TRUE;

    multipart = CAMEL_MULTIPART (content);
    n_parts = camel_multipart_get_number (multipart);

    /* Replace MIME parts with "attachment" or "inline" dispositions
     * with a small "text/plain" part saying the file was removed. */
    for (ii = 0; ii < n_parts; ii++) {
        CamelMimePart *mime_part;
        const gchar *disposition;
        gboolean is_attachment;

        mime_part = camel_multipart_get_part (multipart, ii);
        disposition = camel_mime_part_get_disposition (mime_part);

        is_attachment =
            (g_strcmp0 (disposition, "attachment") == 0) ||
            (g_strcmp0 (disposition, "inline") == 0);

        if (is_attachment) {
            const gchar *filename;
            const gchar *content_type;
            gchar *content;

            disposition = "inline";
            content_type = "text/plain";
            filename = camel_mime_part_get_filename (mime_part);

            if (filename != NULL && *filename != '\0')
                content = g_strdup_printf (
                    _("File \"%s\" has been removed."),
                    filename);
            else
                content = g_strdup (
                    _("File has been removed."));

            camel_mime_part_set_content (
                mime_part, content,
                strlen (content), content_type);
            camel_mime_part_set_content_type (
                mime_part, content_type);
            camel_mime_part_set_disposition (
                mime_part, disposition);

            modified = TRUE;
        }
    }

    /* Append the modified message with removed attachments to
     * the folder and mark the original message for deletion. */
    if (modified) {
        CamelMessageInfo *orig_info;
        CamelMessageInfo *copy_info;
        CamelMessageFlags flags;

        orig_info =
            camel_folder_get_message_info (folder, message_uid);
        copy_info =
            camel_message_info_new_from_header (
            NULL, CAMEL_MIME_PART (message)->headers);

        flags = camel_folder_get_message_flags (folder, message_uid);
        camel_message_info_set_flags (copy_info, flags, flags);

        success = camel_folder_append_message_sync (
            folder, message, copy_info, NULL, cancellable, error);
        if (success)
            camel_message_info_set_flags (
                orig_info,
                CAMEL_MESSAGE_DELETED,
                CAMEL_MESSAGE_DELETED);

        camel_message_info_unref (orig_info);
        camel_message_info_unref (copy_info);
    }

    return success;
}

gboolean
e_mail_folder_remove_attachments_sync (CamelFolder *folder,
                                       GPtrArray *message_uids,
                                       GCancellable *cancellable,
                                       GError **error)
{
    gboolean success = TRUE;
    guint ii;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);
    g_return_val_if_fail (message_uids != NULL, FALSE);

    camel_folder_freeze (folder);

    camel_operation_push_message (cancellable, _("Removing attachments"));

    for (ii = 0; success && ii < message_uids->len; ii++) {
        CamelMimeMessage *message;
        const gchar *uid;
        gint percent;

        uid = g_ptr_array_index (message_uids, ii);

        message = camel_folder_get_message_sync (
            folder, uid, cancellable, error);

        if (message == NULL) {
            success = FALSE;
            break;
        }

        success = mail_folder_strip_message (
            folder, message, uid, cancellable, error);

        percent = ((ii + 1) * 100) / message_uids->len;
        camel_operation_progress (cancellable, percent);

        g_object_unref (message);
    }

    camel_operation_pop_message (cancellable);

    if (success)
        camel_folder_synchronize_sync (
            folder, FALSE, cancellable, error);

    camel_folder_thaw (folder);

    return success;
}

void
e_mail_folder_remove_attachments (CamelFolder *folder,
                                  GPtrArray *message_uids,
                                  gint io_priority,
                                  GCancellable *cancellable,
                                  GAsyncReadyCallback callback,
                                  gpointer user_data)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));
    g_return_if_fail (message_uids != NULL);

    context = g_slice_new0 (AsyncContext);
    context->ptr_array = g_ptr_array_ref (message_uids);

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback, user_data,
        e_mail_folder_remove_attachments);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_set_op_res_gpointer (
        simple, context, (GDestroyNotify) async_context_free);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_remove_attachments_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

gboolean
e_mail_folder_remove_attachments_finish (CamelFolder *folder,
                                         GAsyncResult *result,
                                         GError **error)
{
    GSimpleAsyncResult *simple;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_remove_attachments), FALSE);

    simple = G_SIMPLE_ASYNC_RESULT (result);

    /* Assume success unless a GError is set. */
    return !g_simple_async_result_propagate_error (simple, error);
}

static void
mail_folder_save_messages_thread (GSimpleAsyncResult *simple,
                                  GObject *object,
                                  GCancellable *cancellable)
{
    AsyncContext *context;
    GError *error = NULL;

    context = g_simple_async_result_get_op_res_gpointer (simple);

    e_mail_folder_save_messages_sync (
        CAMEL_FOLDER (object), context->ptr_array,
        context->destination, cancellable, &error);

    if (error != NULL)
        g_simple_async_result_take_error (simple, error);
}

/* Helper for e_mail_folder_save_messages_sync() */
static void
mail_folder_save_prepare_part (CamelMimePart *mime_part)
{
    CamelDataWrapper *content;

    content = camel_medium_get_content (CAMEL_MEDIUM (mime_part));

    if (content == NULL)
        return;

    if (CAMEL_IS_MULTIPART (content)) {
        guint n_parts, ii;

        n_parts = camel_multipart_get_number (
            CAMEL_MULTIPART (content));
        for (ii = 0; ii < n_parts; ii++) {
            mime_part = camel_multipart_get_part (
                CAMEL_MULTIPART (content), ii);
            mail_folder_save_prepare_part (mime_part);
        }

    } else if (CAMEL_IS_MIME_MESSAGE (content)) {
        mail_folder_save_prepare_part (CAMEL_MIME_PART (content));

    } else {
        CamelContentType *type;

        /* Save textual parts as 8-bit, not encoded. */
        type = camel_data_wrapper_get_mime_type_field (content);
        if (camel_content_type_is (type, "text", "*"))
            camel_mime_part_set_encoding (
                mime_part, CAMEL_TRANSFER_ENCODING_8BIT);
    }
}

gboolean
e_mail_folder_save_messages_sync (CamelFolder *folder,
                                  GPtrArray *message_uids,
                                  GFile *destination,
                                  GCancellable *cancellable,
                                  GError **error)
{
    GFileOutputStream *file_output_stream;
    CamelStream *base_stream = NULL;
    GByteArray *byte_array;
    gboolean success = TRUE;
    guint ii;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), FALSE);
    g_return_val_if_fail (message_uids != NULL, FALSE);
    g_return_val_if_fail (G_IS_FILE (destination), FALSE);

    /* Need at least one message UID to save. */
    g_return_val_if_fail (message_uids->len > 0, FALSE);

    camel_operation_push_message (
        cancellable, ngettext (
            "Saving %d message",
            "Saving %d messages",
            message_uids->len),
        message_uids->len);

    file_output_stream = g_file_replace (
        destination, NULL, FALSE,
        G_FILE_CREATE_PRIVATE |
        G_FILE_CREATE_REPLACE_DESTINATION,
        cancellable, error);

    if (file_output_stream == NULL) {
        camel_operation_pop_message (cancellable);
        return FALSE;
    }

    byte_array = g_byte_array_new ();

    for (ii = 0; ii < message_uids->len; ii++) {
        CamelMimeMessage *message;
        CamelMimeFilter *filter;
        CamelStream *stream;
        const gchar *uid;
        gchar *from_line;
        gint percent;
        gint retval;

        if (base_stream != NULL)
            g_object_unref (base_stream);

        /* CamelStreamMem does NOT take ownership of the byte
         * array when set with camel_stream_mem_set_byte_array().
         * This allows us to reuse the same memory slab for each
         * message, which is slightly more efficient. */
        base_stream = camel_stream_mem_new ();
        camel_stream_mem_set_byte_array (
            CAMEL_STREAM_MEM (base_stream), byte_array);

        uid = g_ptr_array_index (message_uids, ii);

        message = camel_folder_get_message_sync (
            folder, uid, cancellable, error);
        if (message == NULL) {
            success = FALSE;
            goto exit;
        }

        mail_folder_save_prepare_part (CAMEL_MIME_PART (message));

        from_line = camel_mime_message_build_mbox_from (message);
        g_return_val_if_fail (from_line != NULL, FALSE);

        success = g_output_stream_write_all (
            G_OUTPUT_STREAM (file_output_stream),
            from_line, strlen (from_line), NULL,
            cancellable, error);

        g_free (from_line);

        if (!success) {
            g_object_unref (message);
            goto exit;
        }

        filter = camel_mime_filter_from_new ();
        stream = camel_stream_filter_new (base_stream);
        camel_stream_filter_add (CAMEL_STREAM_FILTER (stream), filter);

        retval = camel_data_wrapper_write_to_stream_sync (
            CAMEL_DATA_WRAPPER (message),
            stream, cancellable, error);

        g_object_unref (filter);
        g_object_unref (stream);

        if (retval == -1) {
            g_object_unref (message);
            goto exit;
        }

        g_byte_array_append (byte_array, (guint8 *) "\n", 1);

        success = g_output_stream_write_all (
            G_OUTPUT_STREAM (file_output_stream),
            byte_array->data, byte_array->len,
            NULL, cancellable, error);

        if (!success) {
            g_object_unref (message);
            goto exit;
        }

        percent = ((ii + 1) * 100) / message_uids->len;
        camel_operation_progress (cancellable, percent);

        /* Reset the byte array for the next message. */
        g_byte_array_set_size (byte_array, 0);

        g_object_unref (message);
    }

exit:
    if (base_stream != NULL)
        g_object_unref (base_stream);

    g_byte_array_free (byte_array, TRUE);

    g_object_unref (file_output_stream);

    camel_operation_pop_message (cancellable);

    if (!success) {
        /* Try deleting the destination file. */
        g_file_delete (destination, NULL, NULL);
    }

    return success;
}

void
e_mail_folder_save_messages (CamelFolder *folder,
                             GPtrArray *message_uids,
                             GFile *destination,
                             gint io_priority,
                             GCancellable *cancellable,
                             GAsyncReadyCallback callback,
                             gpointer user_data)
{
    GSimpleAsyncResult *simple;
    AsyncContext *context;

    g_return_if_fail (CAMEL_IS_FOLDER (folder));
    g_return_if_fail (message_uids != NULL);
    g_return_if_fail (G_IS_FILE (destination));

    /* Need at least one message UID to save. */
    g_return_if_fail (message_uids->len > 0);

    context = g_slice_new0 (AsyncContext);
    context->ptr_array = g_ptr_array_ref (message_uids);
    context->destination = g_object_ref (destination);

    simple = g_simple_async_result_new (
        G_OBJECT (folder), callback, user_data,
        e_mail_folder_save_messages);

    g_simple_async_result_set_check_cancellable (simple, cancellable);

    g_simple_async_result_set_op_res_gpointer (
        simple, context, (GDestroyNotify) async_context_free);

    g_simple_async_result_run_in_thread (
        simple, mail_folder_save_messages_thread,
        io_priority, cancellable);

    g_object_unref (simple);
}

gboolean
e_mail_folder_save_messages_finish (CamelFolder *folder,
                                    GAsyncResult *result,
                                    GError **error)
{
    GSimpleAsyncResult *simple;

    g_return_val_if_fail (
        g_simple_async_result_is_valid (
        result, G_OBJECT (folder),
        e_mail_folder_save_messages), FALSE);

    simple = G_SIMPLE_ASYNC_RESULT (result);

    /* Assume success unless a GError is set. */
    return !g_simple_async_result_propagate_error (simple, error);
}

/**
 * e_mail_folder_uri_build:
 * @store: a #CamelStore
 * @folder_name: a folder name
 *
 * Builds a folder URI string from @store and @folder_name.
 *
 * Returns: a newly-allocated folder URI string
 **/
gchar *
e_mail_folder_uri_build (CamelStore *store,
                         const gchar *folder_name)
{
    const gchar *uid;
    gchar *encoded_name;
    gchar *encoded_uid;
    gchar *uri;

    g_return_val_if_fail (CAMEL_IS_STORE (store), NULL);
    g_return_val_if_fail (folder_name != NULL, NULL);

    /* Skip the leading slash, if present. */
    if (*folder_name == '/')
        folder_name++;

    uid = camel_service_get_uid (CAMEL_SERVICE (store));

    encoded_uid = camel_url_encode (uid, ":;@/");
    encoded_name = camel_url_encode (folder_name, "#");

    uri = g_strdup_printf ("folder://%s/%s", encoded_uid, encoded_name);

    g_free (encoded_uid);
    g_free (encoded_name);

    return uri;
}

/**
 * e_mail_folder_uri_parse:
 * @session: a #CamelSession
 * @folder_uri: a folder URI
 * @out_store: return location for a #CamelStore, or %NULL
 * @out_folder_name: return location for a folder name, or %NULL
 * @error: return location for a #GError, or %NULL
 *
 * Parses a folder URI generated by e_mail_folder_uri_build() and
 * returns the corresponding #CamelStore instance in @out_store and
 * folder name string in @out_folder_name.  If the URI is malformed
 * or no corresponding store exists, the function sets @error and
 * returns %FALSE.
 *
 * If the function is able to parse the URI, the #CamelStore instance
 * set in @out_store should be unreferenced with g_object_unref() when
 * done with it, and the folder name string set in @out_folder_name
 * should be freed with g_free().
 *
 * The function also handles older style URIs, such as ones where the
 * #CamelStore's #CamelStore::uri string was embedded directly in the
 * folder URI, and account-based URIs that used an "email://" prefix.
 *
 * Returns: %TRUE if @folder_uri could be parsed, %FALSE otherwise
 **/
gboolean
e_mail_folder_uri_parse (CamelSession *session,
                         const gchar *folder_uri,
                         CamelStore **out_store,
                         gchar **out_folder_name,
                         GError **error)
{
    CamelURL *url;
    CamelService *service = NULL;
    gchar *folder_name = NULL;
    gboolean success = FALSE;

    g_return_val_if_fail (CAMEL_IS_SESSION (session), FALSE);
    g_return_val_if_fail (folder_uri != NULL, FALSE);

    url = camel_url_new (folder_uri, error);
    if (url == NULL)
        return FALSE;

    /* Current URI Format: 'folder://' STORE_UID '/' FOLDER_PATH */
    if (g_strcmp0 (url->protocol, "folder") == 0) {

        if (url->host != NULL) {
            gchar *uid;

            if (url->user == NULL || *url->user == '\0')
                uid = g_strdup (url->host);
            else
                uid = g_strconcat (
                    url->user, "@", url->host, NULL);

            service = camel_session_ref_service (session, uid);
            g_free (uid);
        }

        if (url->path != NULL && *url->path == '/')
            folder_name = camel_url_decode_path (url->path + 1);

    /* This style was used to reference accounts by UID before
     * CamelServices themselves had UIDs.  Some examples are:
     *
     * Special cases:
     *
     *   'email://local@local/' FOLDER_PATH
     *   'email://vfolder@local/' FOLDER_PATH
     *
     * General case:
     *
     *   'email://' ACCOUNT_UID '/' FOLDER_PATH
     *
     * Note: ACCOUNT_UID is now equivalent to STORE_UID, and
     *       the STORE_UIDs for the special cases are 'local'
     *       and 'vfolder'.
     */
    } else if (g_strcmp0 (url->protocol, "email") == 0) {
        gchar *uid = NULL;

        /* Handle the special cases. */
        if (g_strcmp0 (url->host, "local") == 0) {
            if (g_strcmp0 (url->user, "local") == 0)
                uid = g_strdup ("local");
            if (g_strcmp0 (url->user, "vfolder") == 0)
                uid = g_strdup ("vfolder");
        }

        /* Handle the general case. */
        if (uid == NULL && url->host != NULL) {
            if (url->user == NULL)
                uid = g_strdup (url->host);
            else
                uid = g_strdup_printf (
                    "%s@%s", url->user, url->host);
        }

        if (uid != NULL) {
            service = camel_session_ref_service (session, uid);
            g_free (uid);
        }

        if (url->path != NULL && *url->path == '/')
            folder_name = camel_url_decode_path (url->path + 1);

    /* CamelFolderInfo URIs used to embed the store's URI, so the
     * folder name is appended as either a path part or a fragment
     * part, depending whether the store's URI used the path part.
     * To determine which it is, you have to check the provider
     * flags for CAMEL_URL_FRAGMENT_IS_PATH. */
    } else {
        gboolean local_mbox_folder;

        /* In Evolution 2.x, the local mail store used mbox
         * format.  camel_session_ref_service_by_url() won't
         * match "mbox:///.../mail/local" folder URIs, since
         * the local mail store is now Maildir format.  Test
         * for this corner case and work around it.
         *
         * The folder path is kept in the fragment part of the
         * URL which makes it easy to test the filesystem path.
         * The suffix "evolution/mail/local" should match both
         * the current XDG-compliant location and the old "dot
         * folder" location (~/.evolution/mail/local). */
        local_mbox_folder =
            (g_strcmp0 (url->protocol, "mbox") == 0) &&
            (url->path != NULL) &&
            g_str_has_suffix (url->path, "evolution/mail/local");

        if (local_mbox_folder) {
            service = camel_session_ref_service (session, "local");
        } else {
            service = camel_session_ref_service_by_url (
                session, url, CAMEL_PROVIDER_STORE);
        }

        if (CAMEL_IS_STORE (service)) {
            CamelProvider *provider;

            provider = camel_service_get_provider (service);

            if (provider->url_flags & CAMEL_URL_FRAGMENT_IS_PATH)
                folder_name = g_strdup (url->fragment);
            else if (url->path != NULL && *url->path == '/')
                folder_name = g_strdup (url->path + 1);
        }
    }

    if (CAMEL_IS_STORE (service) && folder_name != NULL) {
        if (out_store != NULL)
            *out_store = g_object_ref (service);

        if (out_folder_name != NULL) {
            *out_folder_name = folder_name;
            folder_name = NULL;
        }

        success = TRUE;
    } else {
        g_set_error (
            error, CAMEL_FOLDER_ERROR,
            CAMEL_FOLDER_ERROR_INVALID,
            _("Invalid folder URI '%s'"),
            folder_uri);
    }

    if (service != NULL)
        g_object_unref (service);

    g_free (folder_name);

    camel_url_free (url);

    return success;
}

/**
 * e_mail_folder_uri_equal:
 * @session: a #CamelSession
 * @folder_uri_a: a folder URI
 * @folder_uri_b: another folder URI
 *
 * Compares two folder URIs for equality.  If either URI is invalid,
 * the function returns %FALSE.
 *
 * Returns: %TRUE if the URIs are equal, %FALSE if not
 **/
gboolean
e_mail_folder_uri_equal (CamelSession *session,
                         const gchar *folder_uri_a,
                         const gchar *folder_uri_b)
{
    CamelStore *store_a;
    CamelStore *store_b;
    CamelStoreClass *class;
    gchar *folder_name_a;
    gchar *folder_name_b;
    gboolean success_a;
    gboolean success_b;
    gboolean equal = FALSE;

    g_return_val_if_fail (CAMEL_IS_SESSION (session), FALSE);
    g_return_val_if_fail (folder_uri_a != NULL, FALSE);
    g_return_val_if_fail (folder_uri_b != NULL, FALSE);

    success_a = e_mail_folder_uri_parse (
        session, folder_uri_a, &store_a, &folder_name_a, NULL);

    success_b = e_mail_folder_uri_parse (
        session, folder_uri_b, &store_b, &folder_name_b, NULL);

    if (!success_a || !success_b)
        goto exit;

    if (store_a != store_b)
        goto exit;

    /* Doesn't matter which store we use since they're the same. */
    class = CAMEL_STORE_GET_CLASS (store_a);
    g_return_val_if_fail (class->equal_folder_name != NULL, FALSE);

    equal = class->equal_folder_name (folder_name_a, folder_name_b);

exit:
    if (success_a) {
        g_object_unref (store_a);
        g_free (folder_name_a);
    }

    if (success_b) {
        g_object_unref (store_b);
        g_free (folder_name_b);
    }

    return equal;
}

/**
 * e_mail_folder_uri_from_folder:
 * @folder: a #CamelFolder
 *
 * Convenience function for building a folder URI from a #CamelFolder.
 * Free the returned URI string with g_free().
 *
 * Returns: a newly-allocated folder URI string
 **/
gchar *
e_mail_folder_uri_from_folder (CamelFolder *folder)
{
    CamelStore *store;
    const gchar *folder_name;

    g_return_val_if_fail (CAMEL_IS_FOLDER (folder), NULL);

    store = camel_folder_get_parent_store (folder);
    folder_name = camel_folder_get_full_name (folder);

    return e_mail_folder_uri_build (store, folder_name);
}

/**
 * e_mail_folder_uri_to_markup:
 * @session: a #CamelSession
 * @folder_uri: a folder URI
 * @error: return location for a #GError, or %NULL
 *
 * Converts @folder_uri to a markup string suitable for displaying to users.
 * The string consists of the #CamelStore display name (in bold), followed
 * by the folder path.  If the URI is malformed or no corresponding store
 * exists, the function sets @error and returns %NULL.  Free the returned
 * string with g_free().
 *
 * Returns: a newly-allocated markup string, or %NULL
 **/
gchar *
e_mail_folder_uri_to_markup (CamelSession *session,
                             const gchar *folder_uri,
                             GError **error)
{
    CamelStore *store = NULL;
    const gchar *display_name;
    gchar *folder_name = NULL;
    gchar *markup;
    gboolean success;

    g_return_val_if_fail (CAMEL_IS_SESSION (session), NULL);
    g_return_val_if_fail (folder_uri != NULL, NULL);

    success = e_mail_folder_uri_parse (
        session, folder_uri, &store, &folder_name, error);

    if (!success)
        return NULL;

    g_return_val_if_fail (CAMEL_IS_STORE (store), NULL);
    g_return_val_if_fail (folder_name != NULL, NULL);

    display_name = camel_service_get_display_name (CAMEL_SERVICE (store));

    markup = g_markup_printf_escaped (
        "<b>%s</b> : %s", display_name, folder_name);

    g_object_unref (store);
    g_free (folder_name);

    return markup;
}