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authorSverker Eriksson <sverker@erlang.org>2010-07-06 20:28:51 +0200
committerSverker Eriksson <sverker@erlang.org>2010-07-07 14:31:58 +0200
commitac90c289ab5ce18395c5fa53c30b38bc5f50ae1d (patch)
treed2d5c15054299553fdef69113871fe17cf2f59be /erts/emulator/beam/erl_db_tree.c
parent91078fbc7b0719150a0c7749a1de9e5c0c9bbdeb (diff)
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Fix ets:select hanging on ordered_set with empty list as key.
erl_db_tree.c incorrectly used NIL (empty list) as "lastkey" to mark start of the iteration. A real NIL key could then cause a select or match iteration to be restarted over and over again if the last key before a trap happended to be NIL. Changed NIL to THE_NON_VALUE. Should be ok as the initial key value can never be put into any continuation tuple.
Diffstat (limited to 'erts/emulator/beam/erl_db_tree.c')
-rw-r--r--erts/emulator/beam/erl_db_tree.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/erts/emulator/beam/erl_db_tree.c b/erts/emulator/beam/erl_db_tree.c
index b6b3cabafe..96e577ed90 100644
--- a/erts/emulator/beam/erl_db_tree.c
+++ b/erts/emulator/beam/erl_db_tree.c
@@ -1081,11 +1081,12 @@ static int db_select_continue_tree(Process *p,
static int db_select_tree(Process *p, DbTable *tbl,
Eterm pattern, int reverse, Eterm *ret)
{
+ /* Strategy: Traverse backwards to build resulting list from tail to head */
DbTableTree *tb = &tbl->tree;
DbTreeStack* stack;
struct select_context sc;
struct mp_info mpi;
- Eterm lastkey = NIL;
+ Eterm lastkey = THE_NON_VALUE;
Eterm key;
Eterm continuation;
unsigned sz;
@@ -1293,7 +1294,7 @@ static int db_select_count_tree(Process *p, DbTable *tbl,
DbTreeStack* stack;
struct select_count_context sc;
struct mp_info mpi;
- Eterm lastkey = NIL;
+ Eterm lastkey = THE_NON_VALUE;
Eterm key;
Eterm continuation;
unsigned sz;
@@ -1395,7 +1396,7 @@ static int db_select_chunk_tree(Process *p, DbTable *tbl,
DbTreeStack* stack;
struct select_context sc;
struct mp_info mpi;
- Eterm lastkey = NIL;
+ Eterm lastkey = THE_NON_VALUE;
Eterm key;
Eterm continuation;
unsigned sz;
@@ -1636,7 +1637,7 @@ static int db_select_delete_tree(Process *p, DbTable *tbl,
DbTableTree *tb = &tbl->tree;
struct select_delete_context sc;
struct mp_info mpi;
- Eterm lastkey = NIL;
+ Eterm lastkey = THE_NON_VALUE;
Eterm key;
Eterm continuation;
unsigned sz;
@@ -2628,7 +2629,7 @@ static void traverse_backwards(DbTableTree *tb,
{
TreeDbTerm *this, *next;
- if (lastkey == NIL) {
+ if (lastkey == THE_NON_VALUE) {
stack->pos = stack->slot = 0;
if (( this = tb->root ) == NULL) {
return;
@@ -2666,7 +2667,7 @@ static void traverse_forward(DbTableTree *tb,
{
TreeDbTerm *this, *next;
- if (lastkey == NIL) {
+ if (lastkey == THE_NON_VALUE) {
stack->pos = stack->slot = 0;
if (( this = tb->root ) == NULL) {
return;