EMailSession: Add helper functions for sending messages.

New functions:

    e_mail_session_get_fcc_for_message_sync()
    e_mail_session_get_fcc_for_message()
    e_mail_session_get_fcc_for_message_finish()
    e_mail_session_ref_transport()
    e_mail_session_ref_default_transport()
    e_mail_session_ref_transport_for_message()

(cherry picked from commit dea7daf4c33ce4bdd020c19a3440538371b415a7)

1 files changed, 664 insertions, 13 deletions

diff --git a/libemail-engine/e-mail-session-utils.c b/libemail-engine/e-mail-session-utils.c
index ce400c4d10..1ef18017dd 100644
--- a/libemail-engine/e-mail-session-utils.c
+++ b/libemail-engine/e-mail-session-utils.c
@@ -38,7 +38,7 @@
 typedef struct _AsyncContext AsyncContext;
 
 struct _AsyncContext {
-	CamelFolder *sent_folder;
+	CamelFolder *folder;
 
 	CamelMimeMessage *message;
 	CamelMessageInfo *info;
@@ -67,8 +67,8 @@ struct _AsyncContext {
 static void
 async_context_free (AsyncContext *context)
 {
-	if (context->sent_folder != NULL)
-		g_object_unref (context->sent_folder);
+	if (context->folder != NULL)
+		g_object_unref (context->folder);
 
 	if (context->message != NULL)
 		g_object_unref (context->message);
@@ -664,11 +664,11 @@ mail_session_send_to_thread (GSimpleAsyncResult *simple,
 
 	/* Try to extract a CamelFolder from the Sent folder URI. */
 	if (context->sent_folder_uri != NULL) {
-		context->sent_folder = e_mail_session_uri_to_folder_sync (
+		context->folder = e_mail_session_uri_to_folder_sync (
 			session, context->sent_folder_uri, 0,
 			cancellable, &error);
 		if (error != NULL) {
-			g_warn_if_fail (context->sent_folder == NULL);
+			g_warn_if_fail (context->folder == NULL);
 			if (error_messages->len > 0)
 				g_string_append (error_messages, "\n\n");
 			g_string_append_printf (
@@ -681,12 +681,12 @@ mail_session_send_to_thread (GSimpleAsyncResult *simple,
 	}
 
 	/* Fall back to the local Sent folder. */
-	if (context->sent_folder == NULL)
-		context->sent_folder = g_object_ref (local_sent_folder);
+	if (context->folder == NULL)
+		context->folder = g_object_ref (local_sent_folder);
 
 	/* Append the message. */
 	camel_folder_append_message_sync (
-		context->sent_folder, context->message,
+		context->folder, context->message,
 		context->info, NULL, cancellable, &error);
 
 	if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
@@ -697,11 +697,10 @@ mail_session_send_to_thread (GSimpleAsyncResult *simple,
 
 	/* If appending to a remote Sent folder failed,
 	 * try appending to the local Sent folder. */
-	if (context->sent_folder != local_sent_folder) {
+	if (context->folder != local_sent_folder) {
 		const gchar *description;
 
-		description = camel_folder_get_description (
-			context->sent_folder);
+		description = camel_folder_get_description (context->folder);
 
 		if (error_messages->len > 0)
 			g_string_append (error_messages, "\n\n");
@@ -770,9 +769,9 @@ exit:
 	}
 
 	/* Synchronize the Sent folder. */
-	if (context->sent_folder != NULL)
+	if (context->folder != NULL)
 		camel_folder_synchronize_sync (
-			context->sent_folder, FALSE, cancellable, NULL);
+			context->folder, FALSE, cancellable, NULL);
 
 	g_string_free (error_messages, TRUE);
 }
@@ -1008,3 +1007,655 @@ e_mail_session_send_to_finish (EMailSession *session,
 	return !g_simple_async_result_propagate_error (simple, error);
 }
 
+/* Helper for e_mail_session_get_fcc_for_message_sync() */
+static CamelFolder *
+mail_session_try_uri_to_folder (EMailSession *session,
+                                const gchar *folder_uri,
+                                GCancellable *cancellable,
+                                GError **error)
+{
+	CamelFolder *folder;
+	GError *local_error = NULL;
+
+	folder = e_mail_session_uri_to_folder_sync (
+		session, folder_uri, 0, cancellable, &local_error);
+
+	/* Sanity check. */
+	g_return_val_if_fail (
+		((folder != NULL) && (local_error == NULL)) ||
+		((folder == NULL) && (local_error != NULL)), NULL);
+
+	/* Disregard specific errors. */
+
+	/* Invalid URI. */
+	if (g_error_matches (
+		local_error, CAMEL_FOLDER_ERROR,
+		CAMEL_FOLDER_ERROR_INVALID))
+		g_clear_error (&local_error);
+
+	/* Folder not found. */
+	if (g_error_matches (
+		local_error, CAMEL_STORE_ERROR,
+		CAMEL_STORE_ERROR_NO_FOLDER))
+		g_clear_error (&local_error);
+
+	if (local_error != NULL)
+		g_propagate_error (error, local_error);
+
+	return folder;
+}
+
+/* Helper for e_mail_session_get_fcc_for_message_sync() */
+static CamelFolder *
+mail_session_ref_origin_folder (EMailSession *session,
+                                CamelMimeMessage *message,
+                                GCancellable *cancellable,
+                                GError **error)
+{
+	CamelMedium *medium;
+	const gchar *header_name;
+	const gchar *header_value;
+
+	medium = CAMEL_MEDIUM (message);
+
+	/* Check that a "X-Evolution-Source-Flags" header is present
+	 * and its value does not contain the substring "FORWARDED". */
+
+	header_name = "X-Evolution-Source-Flags";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	if (strstr (header_value, "FORWARDED") != NULL)
+		return NULL;
+
+	/* Check that a "X-Evolution-Source-Message" header is present. */
+
+	header_name = "X-Evolution-Source-Message";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	/* Check that a "X-Evolution-Source-Folder" header is present.
+	 * Its value specifies the origin folder as a folder URI. */
+
+	header_name = "X-Evolution-Source-Folder";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	/* This may return NULL without setting a GError. */
+	return mail_session_try_uri_to_folder (
+		session, header_value, cancellable, error);
+}
+
+/* Helper for e_mail_session_get_fcc_for_message_sync() */
+static CamelFolder *
+mail_session_ref_fcc_from_identity (EMailSession *session,
+                                    ESource *source,
+                                    CamelMimeMessage *message,
+                                    GCancellable *cancellable,
+                                    GError **error)
+{
+	ESourceRegistry *registry;
+	ESourceMailSubmission *extension;
+	CamelFolder *folder = NULL;
+	const gchar *extension_name;
+	gchar *folder_uri;
+
+	registry = e_mail_session_get_registry (session);
+	extension_name = E_SOURCE_EXTENSION_MAIL_SUBMISSION;
+
+	if (source == NULL)
+		return NULL;
+
+	if (!e_source_registry_check_enabled (registry, source))
+		return NULL;
+
+	if (!e_source_has_extension (source, extension_name))
+		return NULL;
+
+	extension = e_source_get_extension (source, extension_name);
+
+	if (e_source_mail_submission_get_replies_to_origin_folder (extension)) {
+		GError *local_error = NULL;
+
+		/* This may return NULL without setting a GError. */
+		folder = mail_session_ref_origin_folder (
+			session, message, cancellable, &local_error);
+
+		if (local_error != NULL) {
+			g_warn_if_fail (folder == NULL);
+			g_propagate_error (error, local_error);
+			return NULL;
+		}
+	}
+
+	folder_uri = e_source_mail_submission_dup_sent_folder (extension);
+
+	if (folder_uri != NULL && folder == NULL) {
+		/* This may return NULL without setting a GError. */
+		folder = mail_session_try_uri_to_folder (
+			session, folder_uri, cancellable, error);
+	}
+
+	g_free (folder_uri);
+
+	return folder;
+}
+
+/* Helper for e_mail_session_get_fcc_for_message_sync() */
+static CamelFolder *
+mail_session_ref_fcc_from_x_identity (EMailSession *session,
+                                      CamelMimeMessage *message,
+                                      GCancellable *cancellable,
+                                      GError **error)
+{
+	ESource *source;
+	ESourceRegistry *registry;
+	CamelFolder *folder;
+	CamelMedium *medium;
+	const gchar *header_name;
+	const gchar *header_value;
+	gchar *uid;
+
+	medium = CAMEL_MEDIUM (message);
+	header_name = "X-Evolution-Identity";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	uid = g_strstrip (g_strdup (header_value));
+
+	registry = e_mail_session_get_registry (session);
+	source = e_source_registry_ref_source (registry, uid);
+
+	/* This may return NULL without setting a GError. */
+	folder = mail_session_ref_fcc_from_identity (
+		session, source, message, cancellable, error);
+
+	g_clear_object (&source);
+
+	g_free (uid);
+
+	return folder;
+}
+
+/* Helper for e_mail_session_get_fcc_for_message_sync() */
+static CamelFolder *
+mail_session_ref_fcc_from_x_fcc (EMailSession *session,
+                                 CamelMimeMessage *message,
+                                 GCancellable *cancellable,
+                                 GError **error)
+{
+	CamelMedium *medium;
+	const gchar *header_name;
+	const gchar *header_value;
+
+	medium = CAMEL_MEDIUM (message);
+	header_name = "X-Evolution-Fcc";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	/* This may return NULL without setting a GError. */
+	return mail_session_try_uri_to_folder (
+		session, header_value, cancellable, error);
+}
+
+/* Helper for e_mail_session_get_fcc_for_message_sync() */
+static CamelFolder *
+mail_session_ref_fcc_from_default_identity (EMailSession *session,
+                                            CamelMimeMessage *message,
+                                            GCancellable *cancellable,
+                                            GError **error)
+{
+	ESource *source;
+	ESourceRegistry *registry;
+	CamelFolder *folder;
+
+	registry = e_mail_session_get_registry (session);
+	source = e_source_registry_ref_default_mail_identity (registry);
+
+	/* This may return NULL without setting a GError. */
+	folder = mail_session_ref_fcc_from_identity (
+		session, source, message, cancellable, error);
+
+	g_clear_object (&source);
+
+	return folder;
+}
+
+/**
+ * e_mail_session_get_fcc_for_message_sync:
+ * @session: an #EMailSession
+ * @message: a #CamelMimeMessage
+ * @cancellable: optional #GCancellable object, or %NULL
+ * @error: return location for a #GError, or %NULL
+ *
+ * Obtains the preferred "carbon-copy" folder (a.k.a Fcc) for @message
+ * by first checking @message for an "X-Evolution-Identity" header, and
+ * then an "X-Evolution-Fcc" header.  Failing that, the function checks
+ * the default mail identity (if available), and failing even that, the
+ * function falls back to the Sent folder from the built-in mail store.
+ *
+ * Where applicable, the function attempts to honor the
+ * #ESourceMailSubmission:replies-to-origin-folder preference.
+ *
+ * The returned #CamelFolder is referenced for thread-safety and must be
+ * unreferenced with g_object_unref() when finished with it.
+ *
+ * If a non-recoverable error occurs, the function sets @error and returns
+ * %NULL.
+ *
+ * Returns: a #CamelFolder, or %NULL
+ **/
+CamelFolder *
+e_mail_session_get_fcc_for_message_sync (EMailSession *session,
+                                         CamelMimeMessage *message,
+                                         GCancellable *cancellable,
+                                         GError **error)
+{
+	CamelFolder *folder = NULL;
+
+	g_return_val_if_fail (E_IS_MAIL_SESSION (session), NULL);
+	g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), NULL);
+
+	/* Check for "X-Evolution-Identity" header. */
+	if (folder == NULL) {
+		GError *local_error = NULL;
+
+		/* This may return NULL without setting a GError. */
+		folder = mail_session_ref_fcc_from_x_identity (
+			session, message, cancellable, &local_error);
+
+		if (local_error != NULL) {
+			g_warn_if_fail (folder == NULL);
+			g_propagate_error (error, local_error);
+			return NULL;
+		}
+	}
+
+	/* Check for "X-Evolution-Fcc" header. */
+	if (folder == NULL) {
+		GError *local_error = NULL;
+
+		/* This may return NULL without setting a GError. */
+		folder = mail_session_ref_fcc_from_x_fcc (
+			session, message, cancellable, &local_error);
+
+		if (local_error != NULL) {
+			g_warn_if_fail (folder == NULL);
+			g_propagate_error (error, local_error);
+			return NULL;
+		}
+	}
+
+	/* Check the default mail identity. */
+	if (folder == NULL) {
+		GError *local_error = NULL;
+
+		/* This may return NULL without setting a GError. */
+		folder = mail_session_ref_fcc_from_default_identity (
+			session, message, cancellable, &local_error);
+
+		if (local_error != NULL) {
+			g_warn_if_fail (folder == NULL);
+			g_propagate_error (error, local_error);
+			return NULL;
+		}
+	}
+
+	/* Last resort - local Sent folder. */
+	if (folder == NULL) {
+		folder = e_mail_session_get_local_folder (
+			session, E_MAIL_LOCAL_FOLDER_SENT);
+		g_object_ref (folder);
+	}
+
+	return folder;
+}
+
+/* Helper for e_mail_session_get_fcc_for_message() */
+static void
+mail_session_get_fcc_for_message_thread (GSimpleAsyncResult *simple,
+                                         GObject *source_object,
+                                         GCancellable *cancellable)
+{
+	AsyncContext *async_context;
+	GError *local_error = NULL;
+
+	async_context = g_simple_async_result_get_op_res_gpointer (simple);
+
+	async_context->folder =
+		e_mail_session_get_fcc_for_message_sync (
+			E_MAIL_SESSION (source_object),
+			async_context->message,
+			cancellable, &local_error);
+
+	if (local_error != NULL)
+		g_simple_async_result_take_error (simple, local_error);
+}
+
+/**
+ * e_mail_session_get_fcc_for_message:
+ * @session: an #EMailSession
+ * @message: a #CamelMimeMessage
+ * @io_priority: the I/O priority of the request
+ * @cancellable: optional #GCancellable object, or %NULL
+ * @callback: a #GAsyncReadyCallback to call when the request is satisfied
+ * @user_data: data to pass to the callback function
+ *
+ * Asynchronously obtains the preferred "carbon-copy" folder (a.k.a Fcc) for
+ * @message by first checking @message for an "X-Evolution-Identity" header,
+ * and then an "X-Evolution-Fcc" header.  Failing that, the function checks
+ * the default mail identity (if available), and failing even that, the
+ * function falls back to the Sent folder from the built-in mail store.
+ *
+ * Where applicable, the function attempts to honor the
+ * #ESourceMailSubmission:replies-to-origin-folder preference.
+ *
+ * When the operation is finished, @callback will be called.  You can then
+ * call e_mail_session_get_fcc_for_message_finish() to get the result of the
+ * operation.
+ **/
+void
+e_mail_session_get_fcc_for_message (EMailSession *session,
+                                    CamelMimeMessage *message,
+                                    gint io_priority,
+                                    GCancellable *cancellable,
+                                    GAsyncReadyCallback callback,
+                                    gpointer user_data)
+{
+	GSimpleAsyncResult *simple;
+	AsyncContext *async_context;
+
+	g_return_if_fail (E_IS_MAIL_SESSION (session));
+	g_return_if_fail (CAMEL_IS_MIME_MESSAGE (message));
+
+	async_context = g_slice_new0 (AsyncContext);
+	async_context->message = g_object_ref (message);
+
+	simple = g_simple_async_result_new (
+		G_OBJECT (session), callback, user_data,
+		e_mail_session_get_fcc_for_message);
+
+	g_simple_async_result_set_check_cancellable (simple, cancellable);
+
+	g_simple_async_result_set_op_res_gpointer (
+		simple, async_context, (GDestroyNotify) async_context_free);
+
+	g_simple_async_result_run_in_thread (
+		simple, mail_session_get_fcc_for_message_thread,
+		io_priority, cancellable);
+
+	g_object_unref (simple);
+}
+
+/**
+ * e_mail_session_get_fcc_for_message_finish:
+ * @session: an #EMailSession
+ * @result: a #GAsyncResult
+ * @error: return location for a #GError, or %NULL
+ *
+ * Finishes the operation started with e_mail_session_get_fcc_for_message().
+ *
+ * The returned #CamelFolder is referenced for thread-safety and must be
+ * unreferenced with g_object_unref() when finished with it.
+ *
+ * If a non-recoverable error occurred, the function sets @error and
+ * returns %NULL.
+ *
+ * Returns: a #CamelFolder, or %NULL
+ **/
+CamelFolder *
+e_mail_session_get_fcc_for_message_finish (EMailSession *session,
+                                           GAsyncResult *result,
+                                           GError **error)
+{
+	GSimpleAsyncResult *simple;
+	AsyncContext *async_context;
+
+	g_return_val_if_fail (
+		g_simple_async_result_is_valid (
+		result, G_OBJECT (session),
+		e_mail_session_get_fcc_for_message), NULL);
+
+	simple = G_SIMPLE_ASYNC_RESULT (result);
+	async_context = g_simple_async_result_get_op_res_gpointer (simple);
+
+	if (g_simple_async_result_propagate_error (simple, error))
+		return NULL;
+
+	g_return_val_if_fail (async_context->folder != NULL, NULL);
+
+	return g_object_ref (async_context->folder);
+}
+
+/**
+ * e_mail_session_ref_transport:
+ * @session: an #EMailSession
+ * @transport_uid: the UID of a mail transport
+ *
+ * Returns the transport #CamelService instance for @transport_uid,
+ * verifying first that the @transport_uid is indeed a mail transport and
+ * that the corresponding #ESource is enabled.  If these checks fail, the
+ * function returns %NULL.
+ *
+ * The returned #CamelService is referenced for thread-safety and must be
+ * unreferenced with g_object_unref() when finished with it.
+ *
+ * Returns: a #CamelService, or %NULL
+ **/
+CamelService *
+e_mail_session_ref_transport (EMailSession *session,
+                              const gchar *transport_uid)
+{
+	ESourceRegistry *registry;
+	ESource *source = NULL;
+	CamelService *transport = NULL;
+	const gchar *extension_name;
+
+	g_return_val_if_fail (E_IS_MAIL_SESSION (session), NULL);
+	g_return_val_if_fail (transport_uid != NULL, NULL);
+
+	registry = e_mail_session_get_registry (session);
+	extension_name = E_SOURCE_EXTENSION_MAIL_TRANSPORT;
+
+	source = e_source_registry_ref_source (registry, transport_uid);
+
+	if (source == NULL)
+		goto exit;
+
+	if (!e_source_registry_check_enabled (registry, source))
+		goto exit;
+
+	if (!e_source_has_extension (source, extension_name))
+		goto exit;
+
+	transport = camel_session_ref_service (
+		CAMEL_SESSION (session), transport_uid);
+
+	/* Sanity check. */
+	if (transport != NULL)
+		g_warn_if_fail (CAMEL_IS_TRANSPORT (transport));
+
+exit:
+	g_clear_object (&source);
+
+	return transport;
+}
+
+/* Helper for e_mail_session_ref_default_transport()
+ * and mail_session_ref_transport_from_x_identity(). */
+static CamelService *
+mail_session_ref_transport_for_identity (EMailSession *session,
+                                         ESource *source)
+{
+	ESourceRegistry *registry;
+	ESourceMailSubmission *extension;
+	CamelService *transport = NULL;
+	const gchar *extension_name;
+	gchar *uid;
+
+	registry = e_mail_session_get_registry (session);
+	extension_name = E_SOURCE_EXTENSION_MAIL_SUBMISSION;
+
+	if (source == NULL)
+		return NULL;
+
+	if (!e_source_registry_check_enabled (registry, source))
+		return NULL;
+
+	if (!e_source_has_extension (source, extension_name))
+		return NULL;
+
+	extension = e_source_get_extension (source, extension_name);
+	uid = e_source_mail_submission_dup_transport_uid (extension);
+
+	if (uid != NULL) {
+		transport = e_mail_session_ref_transport (session, uid);
+		g_free (uid);
+	}
+
+	return transport;
+}
+
+/**
+ * e_mail_session_ref_default_transport:
+ * @session: an #EMailSession
+ *
+ * Returns the default transport #CamelService instance according to
+ * #ESourceRegistry's #ESourceRegistry:default-mail-identity setting,
+ * verifying first that the #ESourceMailSubmission:transport-uid named by
+ * the #ESourceRegistry:default-mail-identity is indeed a mail transport,
+ * and that the corresponding #ESource is enabled.  If these checks fail,
+ * the function returns %NULL.
+ *
+ * The returned #CamelService is referenced for thread-safety and must be
+ * unreferenced with g_object_unref() when finished with it.
+ *
+ * Returns: a #CamelService, or %NULL
+ **/
+CamelService *
+e_mail_session_ref_default_transport (EMailSession *session)
+{
+	ESource *source;
+	ESourceRegistry *registry;
+	CamelService *transport;
+
+	g_return_val_if_fail (E_IS_MAIL_SESSION (session), NULL);
+
+	registry = e_mail_session_get_registry (session);
+	source = e_source_registry_ref_default_mail_identity (registry);
+	transport = mail_session_ref_transport_for_identity (session, source);
+	g_clear_object (&source);
+
+	return transport;
+}
+
+/* Helper for e_mail_session_ref_transport_for_message() */
+static CamelService *
+mail_session_ref_transport_from_x_identity (EMailSession *session,
+                                            CamelMimeMessage *message)
+{
+	ESource *source;
+	ESourceRegistry *registry;
+	CamelMedium *medium;
+	CamelService *transport;
+	const gchar *header_name;
+	const gchar *header_value;
+	gchar *uid;
+
+	medium = CAMEL_MEDIUM (message);
+	header_name = "X-Evolution-Identity";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	uid = g_strstrip (g_strdup (header_value));
+
+	registry = e_mail_session_get_registry (session);
+	source = e_source_registry_ref_source (registry, uid);
+	transport = mail_session_ref_transport_for_identity (session, source);
+	g_clear_object (&source);
+
+	g_free (uid);
+
+	return transport;
+}
+
+/* Helper for e_mail_session_ref_transport_for_message() */
+static CamelService *
+mail_session_ref_transport_from_x_transport (EMailSession *session,
+                                             CamelMimeMessage *message)
+{
+	CamelMedium *medium;
+	CamelService *transport;
+	const gchar *header_name;
+	const gchar *header_value;
+	gchar *uid;
+
+	medium = CAMEL_MEDIUM (message);
+	header_name = "X-Evolution-Transport";
+	header_value = camel_medium_get_header (medium, header_name);
+
+	if (header_value == NULL)
+		return NULL;
+
+	uid = g_strstrip (g_strdup (header_value));
+
+	transport = e_mail_session_ref_transport (session, uid);
+
+	g_free (uid);
+
+	return transport;
+}
+
+/**
+ * e_mail_session_ref_transport_for_message:
+ * @session: an #EMailSession
+ * @message: a #CamelMimeMessage
+ *
+ * Returns the preferred transport #CamelService instance for @message by
+ * first checking @message for an "X-Evolution-Identity" header, and then
+ * an "X-Evolution-Transport" header.  Failing that, the function returns
+ * the default transport #CamelService instance (if available).
+ *
+ * The returned #CamelService is referenced for thread-safety and must be
+ * unreferenced with g_object_unref() when finished with it.
+ *
+ * Returns: a #CamelService, or %NULL
+ **/
+CamelService *
+e_mail_session_ref_transport_for_message (EMailSession *session,
+                                          CamelMimeMessage *message)
+{
+	CamelService *transport = NULL;
+
+	g_return_val_if_fail (E_IS_MAIL_SESSION (session), NULL);
+	g_return_val_if_fail (CAMEL_IS_MIME_MESSAGE (message), NULL);
+
+	/* Check for "X-Evolution-Identity" header. */
+	if (transport == NULL)
+		transport = mail_session_ref_transport_from_x_identity (
+			session, message);
+
+	/* Check for "X-Evolution-Transport" header. */
+	if (transport == NULL)
+		transport = mail_session_ref_transport_from_x_transport (
+			session, message);
+
+	/* Fall back to the default mail transport. */
+	if (transport == NULL)
+		transport = e_mail_session_ref_default_transport (session);
+
+	return transport;
+}
+