synchronous set is now asynchronous behind your back

generic/zookeepertcl.c

@@ -452,6 +452,31 @@ zootcl_stat_completion_callback (int rc, const struct Stat *stat, const void *co
  Tcl_ThreadAlert (evPtr->zo->threadId);
 }
 
+/*
+ *--------------------------------------------------------------
+ *
+ * zootcl_sync_stat_completion_callback -- string completion callback function
+ *
+ *--------------------------------------------------------------
+ */
+void
+zootcl_sync_stat_completion_callback (int rc, const struct Stat *stat, const void *context)
+{
+ zootcl_syncCallbackContext *zsc = (zootcl_syncCallbackContext *)context;
+ zootcl_callbackEvent *evPtr;
+ zsc->rc = rc;
+ if (stat != NULL) {
+ zsc->stat = *stat;
+ }
+ zsc->syncDone = 1;
+printf("zootcl_sync_stat_completion_callback: done\n");
+ evPtr = ckalloc (sizeof (zootcl_callbackEvent));
+ evPtr->event.proc = zootcl_EventProc;
+ evPtr->callbackType = NULL_CALLBACK;
+ Tcl_ThreadQueueEvent (zsc->zo->threadId, (Tcl_Event *)evPtr, TCL_QUEUE_TAIL);
+ Tcl_ThreadAlert (zsc->zo->threadId);
+}
+
 /*
  *--------------------------------------------------------------
  *
@@ -749,6 +774,10 @@ zootcl_EventSetupProc (ClientData clientData, int flags) {
 int
 zootcl_EventProc (Tcl_Event *tevPtr, int flags) {
  zootcl_callbackEvent *evPtr = (zootcl_callbackEvent *)tevPtr;
+ if (evPtr->callbackType == NULL_CALLBACK) {
+ return 1;
+ }
+
  zootcl_objectClientData *zo = evPtr->zo;
  Tcl_Interp *interp = zo->interp;
  int tclReturnCode;
@@ -782,6 +811,10 @@ zootcl_EventProc (Tcl_Event *tevPtr, int flags) {
 
 
  switch(evPtr->callbackType) {
+ case NULL_CALLBACK:
+ // should never reach here
+ assert(0 == 1);
+
  case INTERNAL_INIT_CALLBACK:
  // break;
  case WATCHER_CALLBACK:
@@ -933,6 +966,59 @@ zootcl_zookeeperObjectDelete (ClientData clientData)
  ckfree((char *)clientData);
 }
 
+/*
+ *--------------------------------------------------------------
+ *
+ * zootcl_wait -- routine to make sync-like zookeeper functions
+ * wait while keeping the event loop alive.
+ *
+ * this code was derived from Tcl_VwaitObjCmd in the Tcl core
+ *
+ *--------------------------------------------------------------
+ */
+int
+zootcl_wait (zootcl_objectClientData *zo, zootcl_syncCallbackContext *zsc)
+{
+ assert (zo->zookeeper_object_magic == ZOOKEEPER_OBJECT_MAGIC);
+ Tcl_Interp *interp = zo->interp;
+ int foundEvent = 1;
+
+ while (!zsc->syncDone && foundEvent) {
+printf("zootcl_wait: doing an event, stat %d\n", zsc->syncDone);
+ foundEvent = Tcl_DoOneEvent(TCL_ALL_EVENTS);
+printf("zootcl_wait: back from event, stat %d\n", zsc->syncDone);
+
+ if (Tcl_Canceled(interp, TCL_LEAVE_ERR_MSG) == TCL_ERROR) {
+ break;
+ }
+
+ if (Tcl_LimitExceeded(interp)) {
+ Tcl_ResetResult(interp);
+ Tcl_SetObjResult(interp, Tcl_NewStringObj("limit exceeded", -1));
+ break;
+ }
+ }
+
+ if (!foundEvent) {
+ Tcl_ResetResult(interp);
+ Tcl_SetObjResult(interp, Tcl_NewStringObj("can't wait for zookeeper event: would wait forever", -1));
+ Tcl_SetErrorCode(interp, "TCL", "EVENT", "NO_SOURCES", NULL);
+ return TCL_ERROR;
+ }
+
+ if (!zsc->syncDone) {
+ return TCL_ERROR;
+ }
+
+ /*
+ * Clear out the interpreter's result, since it may have been set by event
+ * handlers.
+ */
+
+ Tcl_ResetResult(interp);
+ return TCL_OK;
+}
+
 /*
  *----------------------------------------------------------------------
  *
@@ -1471,13 +1557,21 @@ zootcl_set_subcommand(Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[], ZOOAP
 
  if (callbackObj == NULL) {
  // synchronous set
- status = zoo_set (zh, path, buffer, bufferLen, version);
+ zootcl_syncCallbackContext *zsc = (zootcl_syncCallbackContext *)ckalloc (sizeof (zootcl_syncCallbackContext));
+ zsc->zo = zo;
+ zsc->syncDone = 0;
+ status = zoo_aset (zh, path, buffer, bufferLen, version, zootcl_sync_stat_completion_callback, zsc);
+ if (zootcl_wait (zo, zsc) == TCL_ERROR) {
+ return TCL_ERROR;
+ }
+ int rc = zsc->rc;
+ ckfree (zsc);
+ return zootcl_set_tcl_return_code (interp, rc);
  } else {
  // asynchronous set
  zootcl_callbackContext *ztc = (zootcl_callbackContext *)ckalloc (sizeof (zootcl_callbackContext));
- ztc->callbackObj = callbackObj;
  ztc->zo = zo;
-
+ ztc->callbackObj = callbackObj;
  status = zoo_aset (zh, path, buffer, bufferLen, version, zootcl_stat_completion_callback, ztc);
  }
  return zootcl_set_tcl_return_code (interp, status);
@@ -2000,4 +2094,3 @@ zootcl_zookeeperObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_
 /* vim: set ts=4 sw=4 sts=4 noet : */
 
 
-

generic/zookeepertcl.h

@@ -34,14 +34,22 @@ typedef struct zootcl_objectClientData
  Tcl_Obj *initCallbackObj; // handle callbacks from zookeeper_init callback function
 } zootcl_objectClientData;
 
-enum zootcl_CallbackType {INTERNAL_INIT_CALLBACK, WATCHER_CALLBACK, DATA_CALLBACK, STRING_CALLBACK, VOID_CALLBACK, STAT_CALLBACK};
+enum zootcl_CallbackType {NULL_CALLBACK, INTERNAL_INIT_CALLBACK, WATCHER_CALLBACK, DATA_CALLBACK, STRING_CALLBACK, VOID_CALLBACK, STAT_CALLBACK};
 
 typedef struct zootcl_callbackContext
 {
  zootcl_objectClientData *zo;
  Tcl_Obj *callbackObj;
 } zootcl_callbackContext;
 
+typedef struct zootcl_syncCallbackContext
+{
+ zootcl_objectClientData *zo;
+ int rc;
+ struct Stat stat;
+ int syncDone;
+} zootcl_syncCallbackContext;
+
 // this is the data structure that zookeepertcl queues to tcl
 // to move an event from zookeeper into tcl
 typedef struct zootcl_callbackEvent