tbf: add llc_queue_size() to check llc_queue is valid before calling size()

gcc6 is optimizing if (!this) {CODE} as this is assumed to never be a
std::nullptr here. Move the null check to the caller. In preparation of
removing the check within llc_queue->size(), all callers must check the object
before calling it. Make sure of that: make the llc_queue() access function
protected and offer only a public llc_queue_size() function that incorporates
the NULL check. All current callers are only interested in the
llc_queue_size().

Tweaked-by: nhofmeyr
Change-Id: I88cc3180f8f86785e3f07981895dabddf50b60a2

1 files changed, 4 insertions, 2 deletions

diff --git a/src/tbf.h b/src/tbf.h
index 3a6f42db..37401bfd 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -142,8 +142,7 @@ struct gprs_rlcmac_tbf {
 	uint8_t ms_class() const;
 	void set_ms_class(uint8_t);
 	GprsCodingScheme current_cs() const;
-	gprs_llc_queue *llc_queue();
-	const gprs_llc_queue *llc_queue() const;
+	int llc_queue_size() const;
 
 	time_t created_ts() const;
 	uint8_t dl_slots() const;
@@ -231,6 +230,9 @@ protected:
 	int set_tlli_from_ul(uint32_t new_tlli);
 	void merge_and_clear_ms(GprsMs *old_ms);
 
+	gprs_llc_queue *llc_queue();
+	const gprs_llc_queue *llc_queue() const;
+
 	static const char *tbf_state_name[7];
 
 	class GprsMs *m_ms;