[PATCH v3 13/25] trace-cmd library: Inherit compression algorithm from input file

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

When a new trace file output handler is allocated, based on given trace
file input handler - use the same compression algorithm.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-output.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 627cea42..ea90ef75 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -980,17 +980,27 @@ out_free:
 static int select_file_version(struct tracecmd_output *handle,
 				struct tracecmd_input *ihandle)
 {
+	const char *cname = NULL;
+	const char *cver = NULL;
+
 	if (ihandle) {
 		handle->file_version = tracecmd_get_file_version(ihandle);
-	} else {
-		handle->compress = tracecmd_compress_alloc(NULL, NULL, handle->fd,
-							   handle->pevent, handle->msg_handle);
-		if (handle->compress)
-			handle->file_version = 7;
-		else
-			handle->file_version = 6;
+		if (!tracecmd_get_file_compress_proto(ihandle, &cname, &cver)) {
+			handle->compress = tracecmd_compress_alloc(cname, cver, handle->fd,
+								   handle->pevent, handle->msg_handle);
+			if (!handle->compress)
+				return -1;
+		}
+		return 0;
 	}
 
+	handle->compress = tracecmd_compress_alloc(NULL, NULL, handle->fd,
+						   handle->pevent, handle->msg_handle);
+	if (handle->compress)
+		handle->file_version = 7;
+	else
+		handle->file_version = 6;
+
 	return 0;
 }
 
@@ -1645,6 +1655,8 @@ struct tracecmd_output *tracecmd_get_output_handle_fd(int fd)
 {
 	struct tracecmd_output *handle = NULL;
 	struct tracecmd_input *ihandle;
+	const char *cname = NULL;
+	const char *cver = NULL;
 	int fd2;
 
 	/* Move the file descriptor to the beginning */
@@ -1682,6 +1694,12 @@ struct tracecmd_output *tracecmd_get_output_handle_fd(int fd)
 	handle->file_version = tracecmd_get_file_version(ihandle);
 	list_head_init(&handle->options);
 
+	if (!tracecmd_get_file_compress_proto(ihandle, &cname, &cver)) {
+		handle->compress = tracecmd_compress_alloc(cname, cver, handle->fd,
+							   handle->pevent, handle->msg_handle);
+		if (!handle->compress)
+			goto out_free;
+	}
 	tracecmd_close(ihandle);
 
 	return handle;
-- 
2.31.1