notmuch: Add a 'part' subcommand

A new 'part' subcommand allows the user to extract a single part from
a MIME message. Usage:
  notmuch part --part=<n> <search terms>
The search terms must match only a single message
(e.g. id:foo@bar.com). The part number specified refers to the part
identifiers output by `notmuch show'. The content of the part is
written the stdout with no formatting or identification marks. It is
not JSON formatted.

1 files changed, 92 insertions, 0 deletions

diff --git a/show-message.c b/show-message.c
index 05ced9c4..b1b61be4 100644
--- a/show-message.c
+++ b/show-message.c
@@ -102,3 +102,95 @@ show_message_body (const char *filename,
 
     return ret;
 }
+
+static void
+show_one_part_output (GMimeObject *part)
+{
+    GMimeStream *stream_filter = NULL;
+    GMimeDataWrapper *wrapper;
+    GMimeStream *stream_stdout = g_mime_stream_file_new (stdout);
+
+    stream_filter = g_mime_stream_filter_new(stream_stdout);
+    wrapper = g_mime_part_get_content_object (GMIME_PART (part));
+    if (wrapper && stream_filter)
+	g_mime_data_wrapper_write_to_stream (wrapper, stream_filter);
+    if (stream_filter)
+	g_object_unref(stream_filter);
+}
+
+static void
+show_one_part_worker (GMimeObject *part, int *part_count, int desired_part)
+{
+    if (GMIME_IS_MULTIPART (part)) {
+	GMimeMultipart *multipart = GMIME_MULTIPART (part);
+	int i;
+
+	for (i = 0; i < g_mime_multipart_get_count (multipart); i++) {
+		show_one_part_worker (g_mime_multipart_get_part (multipart, i),
+				      part_count, desired_part);
+	}
+	return;
+    }
+
+    if (GMIME_IS_MESSAGE_PART (part)) {
+	GMimeMessage *mime_message;
+
+	mime_message = g_mime_message_part_get_message (GMIME_MESSAGE_PART (part));
+
+	show_one_part_worker (g_mime_message_get_mime_part (mime_message),
+			      part_count, desired_part);
+
+	return;
+    }
+
+    if (! (GMIME_IS_PART (part)))
+	return;
+
+    *part_count = *part_count + 1;
+
+    if (*part_count == desired_part)
+	    show_one_part_output (part);
+}
+
+notmuch_status_t
+show_one_part (const char *filename, int part)
+{
+	GMimeStream *stream = NULL;
+	GMimeParser *parser = NULL;
+	GMimeMessage *mime_message = NULL;
+	notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;
+	FILE *file = NULL;
+	int part_count = 0;
+
+	file = fopen (filename, "r");
+	if (! file) {
+		fprintf (stderr, "Error opening %s: %s\n", filename, strerror (errno));
+		ret = NOTMUCH_STATUS_FILE_ERROR;
+		goto DONE;
+	}
+
+	stream = g_mime_stream_file_new (file);
+	g_mime_stream_file_set_owner (GMIME_STREAM_FILE (stream), FALSE);
+
+	parser = g_mime_parser_new_with_stream (stream);
+
+	mime_message = g_mime_parser_construct_message (parser);
+
+	show_one_part_worker (g_mime_message_get_mime_part (mime_message),
+			      &part_count, part);
+
+ DONE:
+	if (mime_message)
+		g_object_unref (mime_message);
+
+	if (parser)
+		g_object_unref (parser);
+
+	if (stream)
+		g_object_unref (stream);
+
+	if (file)
+		fclose (file);
+
+	return ret;
+}