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authordkf <donal.k.fellows@manchester.ac.uk>2016-05-21 09:27:30 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2016-05-21 09:27:30 (GMT)
commitca66ff4b66c7c2c37cf104ead999ae2fc8c85747 (patch)
tree41386636fdb87c929e9f9a78888ce2539fa00a3d /generic
parent09ec4a59520b6557298cffe32e679a6733928077 (diff)
parentf74fa93858b232af77de13991c43775c193df25a (diff)
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Fix for [f97d4ee020]; use a two-stage approach to avoid quadratic behavior.
Diffstat (limited to 'generic')
-rw-r--r--generic/tclNamesp.c86
1 files changed, 64 insertions, 22 deletions
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index dfab185..58a86d9 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -1105,8 +1105,6 @@ TclTeardownNamespace(
Interp *iPtr = (Interp *) nsPtr->interp;
register Tcl_HashEntry *entryPtr;
Tcl_HashSearch search;
- Tcl_Namespace *childNsPtr;
- Tcl_Command cmd;
int i;
/*
@@ -1121,16 +1119,31 @@ TclTeardownNamespace(
/*
* Delete all commands in this namespace. Be careful when traversing the
* hash table: when each command is deleted, it removes itself from the
- * command table.
- *
- * Don't optimize to Tcl_NextHashEntry() because of traces.
+ * command table. Because of traces (and the desire to avoid the quadratic
+ * problems of just using Tcl_FirstHashEntry over and over, [Bug
+ * f97d4ee020]) we copy to a temporary array and then delete all those
+ * commands.
*/
- for (entryPtr = Tcl_FirstHashEntry(&nsPtr->cmdTable, &search);
- entryPtr != NULL;
- entryPtr = Tcl_FirstHashEntry(&nsPtr->cmdTable, &search)) {
- cmd = Tcl_GetHashValue(entryPtr);
- Tcl_DeleteCommandFromToken((Tcl_Interp *) iPtr, cmd);
+ while (nsPtr->cmdTable.numEntries > 0) {
+ int length = nsPtr->cmdTable.numEntries;
+ Command **cmds = TclStackAlloc((Tcl_Interp *) iPtr,
+ sizeof(Command *) * length);
+
+ i = 0;
+ for (entryPtr = Tcl_FirstHashEntry(&nsPtr->cmdTable, &search);
+ entryPtr != NULL;
+ entryPtr = Tcl_NextHashEntry(&search)) {
+ cmds[i] = Tcl_GetHashValue(entryPtr);
+ cmds[i]->refCount++;
+ i++;
+ }
+ for (i = 0 ; i < length ; i++) {
+ Tcl_DeleteCommandFromToken((Tcl_Interp *) iPtr,
+ (Tcl_Command) cmds[i]);
+ TclCleanupCommandMacro(cmds[i]);
+ }
+ TclStackFree((Tcl_Interp *) iPtr, cmds);
}
Tcl_DeleteHashTable(&nsPtr->cmdTable);
Tcl_InitHashTable(&nsPtr->cmdTable, TCL_STRING_KEYS);
@@ -1175,25 +1188,54 @@ TclTeardownNamespace(
*
* BE CAREFUL: When each child is deleted, it will divorce itself from its
* parent. You can't traverse a hash table properly if its elements are
- * being deleted. We use only the Tcl_FirstHashEntry function to be safe.
+ * being deleted. Because of traces (and the desire to avoid the
+ * quadratic problems of just using Tcl_FirstHashEntry over and over, [Bug
+ * f97d4ee020]) we copy to a temporary array and then delete all those
+ * namespaces.
*
- * Don't optimize to Tcl_NextHashEntry() because of traces.
+ * Important: leave the hash table itself still live.
*/
#ifndef BREAK_NAMESPACE_COMPAT
- for (entryPtr = Tcl_FirstHashEntry(&nsPtr->childTable, &search);
- entryPtr != NULL;
- entryPtr = Tcl_FirstHashEntry(&nsPtr->childTable, &search)) {
- childNsPtr = Tcl_GetHashValue(entryPtr);
- Tcl_DeleteNamespace(childNsPtr);
+ while (nsPtr->childTable.numEntries > 0) {
+ int length = nsPtr->childTable.numEntries;
+ Namespace **children = TclStackAlloc((Tcl_Interp *) iPtr,
+ sizeof(Namespace *) * length);
+
+ i = 0;
+ for (entryPtr = Tcl_FirstHashEntry(&nsPtr->childTable, &search);
+ entryPtr != NULL;
+ entryPtr = Tcl_NextHashEntry(&search)) {
+ children[i] = Tcl_GetHashValue(entryPtr);
+ children[i]->refCount++;
+ i++;
+ }
+ for (i = 0 ; i < length ; i++) {
+ Tcl_DeleteNamespace((Tcl_Namespace *) children[i]);
+ TclNsDecrRefCount(children[i]);
+ }
+ TclStackFree((Tcl_Interp *) iPtr, children);
}
#else
if (nsPtr->childTablePtr != NULL) {
- for (entryPtr = Tcl_FirstHashEntry(nsPtr->childTablePtr, &search);
- entryPtr != NULL;
- entryPtr = Tcl_FirstHashEntry(nsPtr->childTablePtr,&search)) {
- childNsPtr = Tcl_GetHashValue(entryPtr);
- Tcl_DeleteNamespace(childNsPtr);
+ while (nsPtr->childTablePtr->numEntries > 0) {
+ int length = nsPtr->childTablePtr->numEntries;
+ Namespace **children = TclStackAlloc((Tcl_Interp *) iPtr,
+ sizeof(Namespace *) * length);
+
+ i = 0;
+ for (entryPtr = Tcl_FirstHashEntry(nsPtr->childTablePtr, &search);
+ entryPtr != NULL;
+ entryPtr = Tcl_NextHashEntry(&search)) {
+ children[i] = Tcl_GetHashValue(entryPtr);
+ children[i]->refCount++;
+ i++;
+ }
+ for (i = 0 ; i < length ; i++) {
+ Tcl_DeleteNamespace((Tcl_Namespace *) children[i]);
+ TclNsDecrRefCount(children[i]);
+ }
+ TclStackFree((Tcl_Interp *) iPtr, children);
}
}
#endif