From 7f9589922db4f2006287c1e3fc11e5ab308b9de3 Mon Sep 17 00:00:00 2001 From: Jack Mordaunt Date: Thu, 5 Jun 2025 15:27:24 -0300 Subject: [PATCH] core/sync.select_raw: return a useful index This fixes a flaw in the original implementation: the returned index is actually useless to the caller. This is because the index returned refers to the internal "candidate" list. This list is dynamic, and may not have all of the input channels (if they weren't ready according to chan.can_{recv,send}). That means the index is not guaranteed to mean anything to the caller. The fix introduced here is to return the index into the input slice (recvs,sends) and an enum to specify which input slice that is. If no selection was made, then (-1, .None) is returned to communicate as much. Signed-off-by: Jack Mordaunt --- core/sync/chan/chan.odin | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/core/sync/chan/chan.odin b/core/sync/chan/chan.odin index eca4c28d7..610cf16eb 100644 --- a/core/sync/chan/chan.odin +++ b/core/sync/chan/chan.odin @@ -1105,6 +1105,15 @@ can_send :: proc "contextless" (c: ^Raw_Chan) -> bool { return c.w_waiting == 0 } +/* +Specifies the direction of the selected channel. +*/ +Select_Status :: enum { + None, + Recv, + Send, +} + /* Attempts to either send or receive messages on the specified channels. @@ -1170,7 +1179,7 @@ Output: */ @(require_results) -select_raw :: proc "odin" (recvs: []^Raw_Chan, sends: []^Raw_Chan, send_msgs: []rawptr, recv_out: rawptr) -> (select_idx: int, ok: bool) #no_bounds_check { +select_raw :: proc "odin" (recvs: []^Raw_Chan, sends: []^Raw_Chan, send_msgs: []rawptr, recv_out: rawptr) -> (select_idx: int, status: Select_Status) #no_bounds_check { Select_Op :: struct { idx: int, // local to the slice that was given is_recv: bool, @@ -1204,15 +1213,22 @@ select_raw :: proc "odin" (recvs: []^Raw_Chan, sends: []^Raw_Chan, send_msgs: [] return } - select_idx = rand.int_max(count) if count > 0 else 0 + candidate_idx := rand.int_max(count) if count > 0 else 0 - sel := candidates[select_idx] + sel := candidates[candidate_idx] if sel.is_recv { - ok = recv_raw(recvs[sel.idx], recv_out) + status = .Recv + if !recv_raw(recvs[sel.idx], recv_out) { + return -1, .None + } } else { - ok = send_raw(sends[sel.idx], send_msgs[sel.idx]) + status = .Send + if !send_raw(sends[sel.idx], send_msgs[sel.idx]) { + return -1, .None + } } - return + + return sel.idx, status }