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Diffstat (limited to 'src/interfaces/libpgtcl/pgtclId.c')
-rw-r--r--src/interfaces/libpgtcl/pgtclId.c283
1 files changed, 267 insertions, 16 deletions
diff --git a/src/interfaces/libpgtcl/pgtclId.c b/src/interfaces/libpgtcl/pgtclId.c
index b3985f73216..4ed8f58d57f 100644
--- a/src/interfaces/libpgtcl/pgtclId.c
+++ b/src/interfaces/libpgtcl/pgtclId.c
@@ -12,7 +12,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/interfaces/libpgtcl/Attic/pgtclId.c,v 1.10 1998/05/06 23:53:30 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/interfaces/libpgtcl/Attic/pgtclId.c,v 1.11 1998/06/16 04:10:17 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -26,7 +26,8 @@
#include "pgtclCmds.h"
#include "pgtclId.h"
-int PgEndCopy(Pg_ConnectionId *connid, int *errorCodePtr)
+
+static int PgEndCopy(Pg_ConnectionId *connid, int *errorCodePtr)
{
connid->res_copyStatus = RES_COPY_NONE;
if (PQendcopy(connid->conn)) {
@@ -147,12 +148,14 @@ int PgOutputProc(DRIVER_OUTPUT_PROTO)
return bufSize;
}
-#if (TCL_MAJOR_VERSION == 7 && TCL_MINOR_VERSION == 6)
+#if HAVE_TCL_GETFILEPROC
+
Tcl_File
PgGetFileProc(ClientData cData, int direction)
{
return (Tcl_File)NULL;
}
+
#endif
Tcl_ChannelType Pg_ConnType = {
@@ -184,14 +187,18 @@ PgSetConnectionId(Tcl_Interp *interp, PGconn *conn)
connid->res_copy = -1;
connid->res_copyStatus = RES_COPY_NONE;
connid->results = (PGresult**)ckalloc(sizeof(PGresult*) * RES_START);
- for (i = 0; i < RES_START; i++) connid->results[i] = NULL;
- Tcl_InitHashTable(&connid->notify_hash, TCL_STRING_KEYS);
+ for (i = 0; i < RES_START; i++)
+ connid->results[i] = NULL;
+ connid->notify_list = NULL;
+ connid->notifier_running = 0;
sprintf(connid->id, "pgsql%d", PQsocket(conn));
#if TCL_MAJOR_VERSION == 7 && TCL_MINOR_VERSION == 5
+ /* Original signature (only seen in Tcl 7.5) */
conn_chan = Tcl_CreateChannel(&Pg_ConnType, connid->id, NULL, NULL, (ClientData)connid);
#else
+ /* Tcl 7.6 and later use this */
conn_chan = Tcl_CreateChannel(&Pg_ConnType, connid->id, (ClientData)connid,
TCL_READABLE | TCL_WRITABLE);
#endif
@@ -214,7 +221,7 @@ PgGetConnectionId(Tcl_Interp *interp, char *id, Pg_ConnectionId **connid_p)
conn_chan = Tcl_GetChannel(interp, id, 0);
if(conn_chan == NULL || Tcl_GetChannelType(conn_chan) != &Pg_ConnType) {
Tcl_ResetResult(interp);
- Tcl_AppendResult(interp, id, " is not a valid postgresql connection\n", 0);
+ Tcl_AppendResult(interp, id, " is not a valid postgresql connection", 0);
return (PGconn *)NULL;
}
@@ -232,9 +239,9 @@ PgGetConnectionId(Tcl_Interp *interp, char *id, Pg_ConnectionId **connid_p)
int PgDelConnectionId(DRIVER_DEL_PROTO)
{
Tcl_HashEntry *entry;
- char *hval;
Tcl_HashSearch hsearch;
Pg_ConnectionId *connid;
+ Pg_TclNotifies *notifies;
int i;
connid = (Pg_ConnectionId *)cData;
@@ -245,17 +252,38 @@ int PgDelConnectionId(DRIVER_DEL_PROTO)
}
ckfree((void*)connid->results);
- for (entry = Tcl_FirstHashEntry(&(connid->notify_hash), &hsearch);
- entry != NULL;
- entry = Tcl_NextHashEntry(&hsearch))
- {
- hval = (char*)Tcl_GetHashValue(entry);
- ckfree(hval);
+ /* Release associated notify info */
+ while ((notifies = connid->notify_list) != NULL) {
+ connid->notify_list = notifies->next;
+ for (entry = Tcl_FirstHashEntry(&notifies->notify_hash, &hsearch);
+ entry != NULL;
+ entry = Tcl_NextHashEntry(&hsearch)) {
+ ckfree((char*) Tcl_GetHashValue(entry));
+ }
+ Tcl_DeleteHashTable(&notifies->notify_hash);
+ Tcl_DontCallWhenDeleted(notifies->interp, PgNotifyInterpDelete,
+ (ClientData) notifies);
+ ckfree((void*) notifies);
}
-
- Tcl_DeleteHashTable(&connid->notify_hash);
+
+ /* Turn off the Tcl event source for this connection,
+ * and delete any pending notify events.
+ */
+ PgStopNotifyEventSource(connid);
+
+ /* Close the libpq connection too */
PQfinish(connid->conn);
- ckfree((void*)connid);
+ connid->conn = NULL;
+
+ /*
+ * We must use Tcl_EventuallyFree because we don't want the connid struct
+ * to vanish instantly if Pg_Notify_EventProc is active for it.
+ * (Otherwise, closing the connection from inside a pg_listen callback
+ * could lead to coredump.) Pg_Notify_EventProc can detect that the
+ * connection has been deleted from under it by checking connid->conn.
+ */
+ Tcl_EventuallyFree((ClientData) connid, TCL_DYNAMIC);
+
return 0;
}
@@ -407,3 +435,226 @@ PgGetConnByResultId(Tcl_Interp *interp, char *resid_c)
}
+
+
+/********************************************
+ Notify event source
+
+ These functions allow asynchronous notify messages arriving from
+ the SQL server to be dispatched as Tcl events. See the Tcl
+ Notifier(3) man page for more info.
+
+ The main trick in this code is that we have to cope with status changes
+ between the queueing and the execution of a Tcl event. For example,
+ if the user changes or cancels the pg_listen callback command, we should
+ use the new setting; we do that by not resolving the notify relation
+ name until the last possible moment.
+ We also have to handle closure of the channel or deletion of the interpreter
+ to be used for the callback (note that with multiple interpreters,
+ the channel can outlive the interpreter it was created by!)
+ Upon closure of the channel, we immediately delete any pending events
+ that reference it. But for interpreter deletion, we just set any
+ matching interp pointers in the Pg_TclNotifies list to NULL. The
+ list item stays around until the connection is deleted. (This avoids
+ trouble with walking through a list whose members may get deleted under us.)
+ *******************************************/
+
+typedef struct {
+ Tcl_Event header; /* Standard Tcl event info */
+ PGnotify info; /* Notify name from SQL server */
+ Pg_ConnectionId *connid; /* Connection for server */
+} NotifyEvent;
+
+/* Setup before waiting in event loop */
+
+static void Pg_Notify_SetupProc (ClientData clientData, int flags)
+{
+ Pg_ConnectionId *connid = (Pg_ConnectionId *) clientData;
+ Tcl_File handle;
+
+ /* We classify SQL notifies as Tcl file events. */
+ if (!(flags & TCL_FILE_EVENTS)) {
+ return;
+ }
+
+ /* Set up to watch for asynchronous data arrival on backend channel */
+ handle = Tcl_GetFile((ClientData) PQsocket(connid->conn), TCL_UNIX_FD);
+ Tcl_WatchFile(handle, TCL_READABLE);
+}
+
+/* Check to see if events have arrived in event loop */
+
+static void Pg_Notify_CheckProc (ClientData clientData, int flags)
+{
+ Pg_ConnectionId *connid = (Pg_ConnectionId *) clientData;
+ Tcl_File handle;
+
+ /* We classify SQL notifies as Tcl file events. */
+ if (!(flags & TCL_FILE_EVENTS)) {
+ return;
+ }
+
+ /* Consume any data available from the SQL server
+ * (this just buffers it internally to libpq).
+ * We use Tcl_FileReady to avoid a useless kernel call
+ * when no data is available.
+ */
+ handle = Tcl_GetFile((ClientData) PQsocket(connid->conn), TCL_UNIX_FD);
+ if (Tcl_FileReady(handle, TCL_READABLE) != 0) {
+ PQconsumeInput(connid->conn);
+ }
+
+ /* Transfer notify events from libpq to Tcl event queue. */
+ PgNotifyTransferEvents(connid);
+}
+
+/* Dispatch an event that has reached the front of the event queue */
+
+static int Pg_Notify_EventProc (Tcl_Event *evPtr, int flags)
+{
+ NotifyEvent *event = (NotifyEvent *) evPtr;
+ Pg_TclNotifies *notifies;
+ Tcl_HashEntry *entry;
+ char *callback;
+ char *svcallback;
+
+ /* We classify SQL notifies as Tcl file events. */
+ if (!(flags & TCL_FILE_EVENTS)) {
+ return 0;
+ }
+
+ /* Preserve/Release to ensure the connection struct doesn't disappear
+ * underneath us.
+ */
+ Tcl_Preserve((ClientData) event->connid);
+
+ /*
+ * Loop for each interpreter that has ever registered on the connection.
+ * Each one can get a callback.
+ */
+
+ for (notifies = event->connid->notify_list;
+ notifies != NULL;
+ notifies = notifies->next) {
+ Tcl_Interp *interp = notifies->interp;
+ if (interp == NULL)
+ continue; /* ignore deleted interpreter */
+ /*
+ * Find the callback to be executed for this interpreter, if any.
+ */
+ entry = Tcl_FindHashEntry(&notifies->notify_hash,
+ event->info.relname);
+ if (entry == NULL)
+ continue; /* no pg_listen in this interpreter */
+ callback = (char *) Tcl_GetHashValue(entry);
+ if (callback == NULL)
+ continue; /* safety check -- shouldn't happen */
+ /*
+ * We have to copy the callback string in case the user executes
+ * a new pg_listen during the callback.
+ */
+ svcallback = (char *) ckalloc((unsigned) (strlen(callback) + 1));
+ strcpy(svcallback, callback);
+ /*
+ * Execute the callback.
+ */
+ Tcl_Preserve((ClientData) interp);
+ if (Tcl_GlobalEval(interp, svcallback) != TCL_OK) {
+ Tcl_AddErrorInfo(interp, "\n (\"pg_listen\" script)");
+ Tcl_BackgroundError(interp);
+ }
+ Tcl_Release((ClientData) interp);
+ ckfree(svcallback);
+ /*
+ * Check for the possibility that the callback closed the connection.
+ */
+ if (event->connid->conn == NULL)
+ break;
+ }
+
+ Tcl_Release((ClientData) event->connid);
+
+ return 1;
+}
+
+/*
+ * Transfer any notify events available from libpq into the Tcl event queue.
+ * Note that this must be called after each PQexec (to capture notifies
+ * that arrive during command execution) as well as in Pg_Notify_CheckProc
+ * (to capture notifies that arrive when we're idle).
+ */
+
+void PgNotifyTransferEvents (Pg_ConnectionId *connid)
+{
+ PGnotify *notify;
+
+ while ((notify = PQnotifies(connid->conn)) != NULL) {
+ NotifyEvent *event = (NotifyEvent *) ckalloc(sizeof(NotifyEvent));
+ event->header.proc = Pg_Notify_EventProc;
+ event->info = *notify;
+ event->connid = connid;
+ Tcl_QueueEvent((Tcl_Event *) event, TCL_QUEUE_TAIL);
+ free(notify);
+ }
+}
+
+/*
+ * Cleanup code for coping when an interpreter or a channel is deleted.
+ *
+ * PgNotifyInterpDelete is registered as an interpreter deletion callback
+ * for each extant Pg_TclNotifies structure.
+ * NotifyEventDeleteProc is used by PgStopNotifyEventSource to get
+ * rid of pending Tcl events that reference a dying connection.
+ */
+
+void PgNotifyInterpDelete(ClientData clientData, Tcl_Interp *interp)
+{
+ /* Mark the interpreter dead, but don't do anything else yet */
+ Pg_TclNotifies *notifies = (Pg_TclNotifies *) clientData;
+ notifies->interp = NULL;
+}
+
+/* Comparison routine for detecting events to be removed by DeleteEvent */
+static int NotifyEventDeleteProc(Tcl_Event *evPtr, ClientData clientData)
+{
+ NotifyEvent *event;
+ Pg_ConnectionId *connid = (Pg_ConnectionId *) clientData;
+
+ if (evPtr->proc != Pg_Notify_EventProc) {
+ return 0;
+ }
+ event = (NotifyEvent *) evPtr;
+ if (event->connid != connid) {
+ return 0;
+ }
+ return 1;
+}
+
+/* Start and stop the notify event source for a connection.
+ * We do not bother to run the notifier unless at least one
+ * pg_listen has been executed on the connection. Currently,
+ * once started the notifier is run until the connection is
+ * closed.
+ */
+
+void PgStartNotifyEventSource(Pg_ConnectionId *connid)
+{
+ /* Start the notify event source if it isn't already running */
+ if (! connid->notifier_running) {
+ Tcl_CreateEventSource(Pg_Notify_SetupProc, Pg_Notify_CheckProc,
+ (ClientData) connid);
+ connid->notifier_running = 1;
+ }
+}
+
+void PgStopNotifyEventSource(Pg_ConnectionId *connid)
+{
+ /* Remove the event source */
+ if (connid->notifier_running) {
+ Tcl_DeleteEventSource(Pg_Notify_SetupProc, Pg_Notify_CheckProc,
+ (ClientData) connid);
+ connid->notifier_running = 0;
+ }
+ /* Kill any queued Tcl events that reference this channel */
+ Tcl_DeleteEvents(NotifyEventDeleteProc, (ClientData) connid);
+}
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