gh-84570: Factor Out _channel_send_wait() (gh-110949)

This makes several subsequent changes cleaner.

Author: ericsnowcurrently

Modules/_xxinterpchannelsmodule.c

@@ -1640,6 +1640,34 @@ _channel_send(_channels *channels, int64_t id, PyObject *obj,
     return 0;
 }
 
+static int
+_channel_send_wait(_channels *channels, int64_t cid, PyObject *obj)
+{
+    PyThread_type_lock mutex = PyThread_allocate_lock();
+    if (mutex == NULL) {
+        PyErr_NoMemory();
+        return -1;
+    }
+    PyThread_acquire_lock(mutex, NOWAIT_LOCK);
+
+    /* Queue up the object. */
+    int res = _channel_send(channels, cid, obj, mutex);
+    if (res < 0) {
+        PyThread_release_lock(mutex);
+        goto finally;
+    }
+
+    /* Wait until the object is received. */
+    wait_for_lock(mutex);
+
+    /* success! */
+    res = 0;
+
+finally:
+    // XXX Delete the lock.
+    return res;
+}
+
 static int
 _channel_recv(_channels *channels, int64_t id, PyObject **res)
 {
@@ -2526,30 +2554,16 @@ channel_send(PyObject *self, PyObject *args, PyObject *kwds)
     }
     cid = cid_data.cid;
 
+    /* Queue up the object. */
+    int err = 0;
     if (blocking) {
-        PyThread_type_lock mutex = PyThread_allocate_lock();
-        if (mutex == NULL) {
-            PyErr_NoMemory();
-            return NULL;
-        }
-        PyThread_acquire_lock(mutex, WAIT_LOCK);
-
-        /* Queue up the object. */
-        int err = _channel_send(&_globals.channels, cid, obj, mutex);
-        if (handle_channel_error(err, self, cid)) {
-            PyThread_release_lock(mutex);
-            return NULL;
-        }
-
-        /* Wait until the object is received. */
-        wait_for_lock(mutex);
+        err = _channel_send_wait(&_globals.channels, cid, obj);
     }
     else {
-        /* Queue up the object. */
-        int err = _channel_send(&_globals.channels, cid, obj, NULL);
-        if (handle_channel_error(err, self, cid)) {
-            return NULL;
-        }
+        err = _channel_send(&_globals.channels, cid, obj, NULL);
+    }
+    if (handle_channel_error(err, self, cid)) {
+        return NULL;
     }
 
     Py_RETURN_NONE;
@@ -2584,33 +2598,17 @@ channel_send_buffer(PyObject *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
 
+    /* Queue up the object. */
+    int err = 0;
     if (blocking) {
-        PyThread_type_lock mutex = PyThread_allocate_lock();
-        if (mutex == NULL) {
-            Py_DECREF(tempobj);
-            PyErr_NoMemory();
-            return NULL;
-        }
-        PyThread_acquire_lock(mutex, WAIT_LOCK);
-
-        /* Queue up the buffer. */
-        int err = _channel_send(&_globals.channels, cid, tempobj, mutex);
-        Py_DECREF(tempobj);
-        if (handle_channel_error(err, self, cid)) {
-            PyThread_acquire_lock(mutex, WAIT_LOCK);
-            return NULL;
-        }
-
-        /* Wait until the buffer is received. */
-        wait_for_lock(mutex);
+        err = _channel_send_wait(&_globals.channels, cid, tempobj);
     }
     else {
-        /* Queue up the buffer. */
-        int err = _channel_send(&_globals.channels, cid, tempobj, NULL);
-        Py_DECREF(tempobj);
-        if (handle_channel_error(err, self, cid)) {
-            return NULL;
-        }
+        err = _channel_send(&_globals.channels, cid, tempobj, NULL);
+    }
+    Py_DECREF(tempobj);
+    if (handle_channel_error(err, self, cid)) {
+        return NULL;
     }
 
     Py_RETURN_NONE;