diff options
Diffstat (limited to 'ext/rtree/rtree.c')
| -rw-r--r-- | ext/rtree/rtree.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/ext/rtree/rtree.c b/ext/rtree/rtree.c index 8f67c801b..b805676b7 100644 --- a/ext/rtree/rtree.c +++ b/ext/rtree/rtree.c @@ -2322,6 +2322,12 @@ splitnode_out: ** If node pLeaf is not the root of the r-tree and its pParent pointer is ** still NULL, load all ancestor nodes of pLeaf into memory and populate ** the pLeaf->pParent chain all the way up to the root node. +** +** This operation is required when a row is deleted (or updated - an update +** is implemented as a delete followed by an insert). SQLite provides the +** rowid of the row to delete, which can be used to find the leaf on which +** the entry resides (argument pLeaf). Once the leaf is located, this +** function is called to determine its ancestry. */ static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){ int rc = SQLITE_OK; @@ -2331,8 +2337,15 @@ static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){ sqlite3_bind_int64(pRtree->pReadParent, 1, pChild->iNode); rc = sqlite3_step(pRtree->pReadParent); if( rc==SQLITE_ROW ){ - RtreeNode *pTest; - i64 iNode = sqlite3_column_int64(pRtree->pReadParent, 0); + RtreeNode *pTest; /* Used to test for reference loops */ + i64 iNode; /* Node number of parent node */ + + /* Before setting pChild->pParent, test that we are not creating a + ** loop of references (as we would if, say, pChild==pParent). We don't + ** want to do this as it leads to a memory leak when trying to delete + ** the referenced counted node structures. + */ + iNode = sqlite3_column_int64(pRtree->pReadParent, 0); for(pTest=pLeaf; pTest && pTest->iNode!=iNode; pTest=pTest->pParent); if( !pTest ){ rc2 = nodeAcquire(pRtree, iNode, 0, &pChild->pParent); |