Synthesize a flush_chan upcall right before a channel's ref_count drops to zero. This should only happen in the Rust code and not in the drop glue, or on the unwind path. This change allows the task owning the channel to block on a flush and delete its own channel. This change also cleans up some code around rust_port and rust_chan.

1 files changed, 21 insertions, 3 deletions

diff --git a/src/rt/rust_port.cpp b/src/rt/rust_port.cpp
index bd9af6f9643..c97b5d4170a 100644
--- a/src/rt/rust_port.cpp
+++ b/src/rt/rust_port.cpp
@@ -21,14 +21,32 @@ rust_port::~rust_port() {
 
     // Disassociate channels from this port.
     while (chans.is_empty() == false) {
-        chans.pop()->disassociate();
+        rust_chan *chan = chans.peek();
+        chan->disassociate();
     }
 
-    // We're the only ones holding a reference to the remote channel, so
-    // clean it up.
     delete remote_channel;
 }
 
+bool rust_port::receive(void *dptr) {
+    for (uint32_t i = 0; i < chans.length(); i++) {
+        rust_chan *chan = chans[i];
+        if (chan->buffer.is_empty() == false) {
+            chan->buffer.dequeue(dptr);
+            if (chan->buffer.is_empty() && chan->task->blocked()) {
+                task->log(rust_log::COMM,
+                          "chan: 0x%" PRIxPTR
+                          " is flushing, wakeup task: 0x%" PRIxPTR,
+                          chan, chan->task);
+                chan->task->wakeup(this);
+            }
+            task->log(rust_log::COMM, "<=== read data ===");
+            return true;
+        }
+    }
+    return false;
+}
+
 void rust_port::log_state() {
     task->log(rust_log::COMM,
               "rust_port: 0x%" PRIxPTR ", associated channel(s): %d",