EMailParserExtension: Collect EMailParts in a GQueue.

Collect EMailParts in a GQueue provided to the EMailParserExtension,
and change the return type of parse() to gboolean to indicate whether
the given CamelMimePart was handled (even if no parts were added to
the output GQueue).

This avoids the awkward corner case of a parser extension returning a
linked list node with a NULL data member to indicate the CamelMimePart
was handled but no EMailParts produced, and then having to watch out
for that NULL data member corner case throughout the application.

Also, remove the GCancellable parameter from e_mail_parser_error() and
e_mail_parser_wrap_as_attachment() since neither function blocks.

1 files changed, 22 insertions, 20 deletions

diff --git a/em-format/e-mail-parser-message-rfc822.c b/em-format/e-mail-parser-message-rfc822.c
index 4632c6e0eb..70bf8c89ed 100644
--- a/em-format/e-mail-parser-message-rfc822.c
+++ b/em-format/e-mail-parser-message-rfc822.c
@@ -62,14 +62,14 @@ static const gchar * parser_mime_types[] = { "message/rfc822",
 					    "message/news",
 					    NULL };
 
-static GSList *
+static gboolean
 empe_msg_rfc822_parse (EMailParserExtension *extension,
                        EMailParser *eparser,
                        CamelMimePart *part,
                        GString *part_id,
-                       GCancellable *cancellable)
+                       GCancellable *cancellable,
+                       GQueue *out_mail_parts)
 {
-	GSList *parts = NULL;
 	EMailPart *mail_part;
 	gint len;
 	CamelMimePart *message;
@@ -81,13 +81,14 @@ empe_msg_rfc822_parse (EMailParserExtension *extension,
 	len = part_id->len;
 	g_string_append (part_id, ".rfc822");
 
-        /* Create an empty PURI that will represent start of the RFC message */
+	/* Create an empty PURI that will represent start of the RFC message */
 	mail_part = e_mail_part_new (part, part_id->str);
 	mail_part->mime_type = g_strdup ("message/rfc822");
-	parts = g_slist_append (NULL, mail_part);
+	g_queue_push_tail (out_mail_parts, mail_part);
 
-	/* Sometime the _actual_ message is encapsulated in another CamelMimePart,
-	 * sometimes the CamelMimePart actually represents the RFC822 message */
+	/* Sometime the actual message is encapsulated in another
+	 * CamelMimePart, sometimes the CamelMimePart itself represents
+	 * the RFC822 message. */
 	ct = camel_mime_part_get_content_type (part);
 	if (camel_content_type_is (ct, "message", "rfc822")) {
 		new_stream = camel_stream_mem_new ();
@@ -110,28 +111,29 @@ empe_msg_rfc822_parse (EMailParserExtension *extension,
 		message = g_object_ref (part);
 	}
 
-	parts = g_slist_concat (parts, e_mail_parser_parse_part_as (
-						eparser, message, part_id,
-						"application/vnd.evolution.message",
-						cancellable));
+	e_mail_parser_parse_part_as (
+		eparser, message, part_id,
+		"application/vnd.evolution.message",
+		cancellable, out_mail_parts);
 
 	g_object_unref (message);
 
-        /* Add another generic EMailPart that represents end of the RFC message.
-         * The em_format_write() function will skip all parts between the ".rfc822"
-         * part and ".rfc822.end" part as they will be rendered in an <iframe> */
+	/* Add another generic EMailPart that represents end of the RFC
+	 * message.  The em_format_write() function will skip all parts
+	 * between the ".rfc822" part and ".rfc822.end" part as they will
+	 * be rendered in an <iframe>. */
 	g_string_append (part_id, ".end");
 	mail_part = e_mail_part_new (message, part_id->str);
 	mail_part->is_hidden = TRUE;
-	parts = g_slist_append (parts, mail_part);
+	g_queue_push_tail (out_mail_parts, mail_part);
+
 	g_string_truncate (part_id, len);
 
-	if (e_mail_part_is_attachment (message)) {
-		return e_mail_parser_wrap_as_attachment (
-			eparser, message, parts, part_id, cancellable);
-	}
+	if (e_mail_part_is_attachment (message))
+		e_mail_parser_wrap_as_attachment (
+			eparser, message, part_id, out_mail_parts);
 
-	return parts;
+	return TRUE;
 }
 
 static guint32