Tweak MIDLs, catch errors.

Grow midls earlier in order to catch errors earlier.  Use
mdb_midl_need() instead of mdb_midl_grow(), then mdb_midl_xappend()
needs no error checks. Factor out mdb_midl_append_range().

libraries/liblmdb/mdb.c

@@ -1438,8 +1438,8 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 		if (!mop) {
 			if (!(env->me_pghead = mop = mdb_midl_alloc(i)))
 				return ENOMEM;
-		} else if (mop_len+i > mop[-1]) {
+		} else {
-			if ((rc = mdb_midl_grow(&env->me_pghead, i)) != 0)
+			if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)
 				return rc;
 			mop = env->me_pghead;
 		}
@@ -1538,12 +1538,13 @@ mdb_page_touch(MDB_cursor *mc)
 	int rc;
 
 	if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
-		if ((rc = mdb_page_alloc(mc, 1, &np)))
+		if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
+			(rc = mdb_page_alloc(mc, 1, &np)))
 			return rc;
 		pgno = np->mp_pgno;
 		DPRINTF("touched db %u page %zu -> %zu", mc->mc_dbi,mp->mp_pgno,pgno);
 		assert(mp->mp_pgno != pgno);
-		mdb_midl_append(&txn->mt_free_pgs, mp->mp_pgno);
+		mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
 		/* Update the parent page, if any, to point to the new page */
 		if (mc->mc_top) {
 			MDB_page *parent = mc->mc_pg[mc->mc_top-1];
@@ -4207,16 +4208,11 @@ mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
 	 */
 	if ((mp->mp_flags & P_DIRTY) && !txn->mt_parent && txn->mt_env->me_pghead) {
 		unsigned j, x;
-		pgno_t *mop = txn->mt_env->me_pghead;
+		pgno_t *mop;
 		MDB_ID2 *dl, ix, iy;
-		/* Prepare to insert pg */
+		rc = mdb_midl_need(&txn->mt_env->me_pghead, ovpages);
-		j = mop[0] + ovpages;
+		if (rc)
-		if (j > mop[-1]) {
+			return rc;
-			rc = mdb_midl_grow(&mop, ovpages);
-			if (rc)
-				return rc;
-			txn->mt_env->me_pghead = mop;
-		}
 		/* Remove from dirty list */
 		dl = txn->mt_u.dirty_list;
 		x = dl[0].mid--;
@@ -4231,16 +4227,17 @@ mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
 			}
 		}
 		/* Insert in me_pghead */
+		mop = txn->mt_env->me_pghead;
+		j = mop[0] + ovpages;
 		for (i = mop[0]; i && mop[i] < pg; i--)
 			mop[j--] = mop[i];
 		while (j>i)
 			mop[j--] = pg++;
 		mop[0] += ovpages;
 	} else {
-		for (i=0; i<ovpages; i++) {
+		rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
-			mdb_midl_append(&txn->mt_free_pgs, pg);
+		if (rc)
-			pg++;
+			return rc;
-		}
 	}
 	mc->mc_db->md_overflow_pages -= ovpages;
 	return 0;
@@ -5229,7 +5226,8 @@ current:
 					memcpy(METADATA(omp), data->mv_data, data->mv_size);
 				goto done;
 			} else {
-				mdb_ovpage_free(mc, omp);
+				if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)
+					return rc2;
 			}
 		} else if (NODEDSZ(leaf) == data->mv_size) {
 			/* same size, just replace it. Note that we could
@@ -6308,7 +6306,10 @@ mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
 			return rc;
 	}
 
-	mdb_midl_append(&csrc->mc_txn->mt_free_pgs, csrc->mc_pg[csrc->mc_top]->mp_pgno);
+	rc = mdb_midl_append(&csrc->mc_txn->mt_free_pgs,
+		csrc->mc_pg[csrc->mc_top]->mp_pgno);
+	if (rc)
+		return rc;
 	if (IS_LEAF(csrc->mc_pg[csrc->mc_top]))
 		csrc->mc_db->md_leaf_pages--;
 	else
@@ -6409,7 +6410,9 @@ mdb_rebalance(MDB_cursor *mc)
 			mc->mc_db->md_root = P_INVALID;
 			mc->mc_db->md_depth = 0;
 			mc->mc_db->md_leaf_pages = 0;
-			mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
+			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
+			if (rc)
+				return rc;
 			/* Adjust cursors pointing to mp */
 			mc->mc_snum = 0;
 			mc->mc_top = 0;
@@ -6434,7 +6437,9 @@ mdb_rebalance(MDB_cursor *mc)
 			}
 		} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
 			DPUTS("collapsing root page!");
-			mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
+			rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
+			if (rc)
+				return rc;
 			mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
 			rc = mdb_page_get(mc->mc_txn,mc->mc_db->md_root,&mc->mc_pg[0],NULL);
 			if (rc)
@@ -6539,10 +6544,9 @@ mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf)
 		pgno_t pg;
 
 		memcpy(&pg, NODEDATA(leaf), sizeof(pg));
-		if ((rc = mdb_page_get(mc->mc_txn, pg, &omp, NULL)) != 0)
+		if ((rc = mdb_page_get(mc->mc_txn, pg, &omp, NULL)) ||
+			(rc = mdb_ovpage_free(mc, omp)))
 			return rc;
-		assert(IS_OVERFLOW(omp));
-		mdb_ovpage_free(mc, omp);
 	}
 	mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], mc->mc_db->md_pad);
 	mc->mc_db->md_entries--;
@@ -7312,7 +7316,6 @@ mdb_drop0(MDB_cursor *mc, int subs)
 				for (i=0; i<n; i++) {
 					ni = NODEPTR(mp, i);
 					if (ni->mn_flags & F_BIGDATA) {
-						int j, ovpages;
 						MDB_page *omp;
 						pgno_t pg;
 						memcpy(&pg, NODEDATA(ni), sizeof(pg));
@@ -7320,11 +7323,10 @@ mdb_drop0(MDB_cursor *mc, int subs)
 						if (rc != 0)
 							return rc;
 						assert(IS_OVERFLOW(omp));
-						ovpages = omp->mp_pages;
+						rc = mdb_midl_append_range(&txn->mt_free_pgs,
-						for (j=0; j<ovpages; j++) {
+							pg, omp->mp_pages);
-							mdb_midl_append(&txn->mt_free_pgs, pg);
+						if (rc)
-							pg++;
+							return rc;
-						}
 					} else if (subs && (ni->mn_flags & F_SUBDATA)) {
 						mdb_xcursor_init1(mc, ni);
 						rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
@@ -7333,12 +7335,14 @@ mdb_drop0(MDB_cursor *mc, int subs)
 					}
 				}
 			} else {
+				if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
+					return rc;
 				for (i=0; i<n; i++) {
 					pgno_t pg;
 					ni = NODEPTR(mp, i);
 					pg = NODEPGNO(ni);
 					/* free it */
-					mdb_midl_append(&txn->mt_free_pgs, pg);
+					mdb_midl_xappend(txn->mt_free_pgs, pg);
 				}
 			}
 			if (!mc->mc_top)
@@ -7358,9 +7362,11 @@ mdb_drop0(MDB_cursor *mc, int subs)
 			}
 		}
 		/* free it */
-		mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
+		rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
+	} else if (rc == MDB_NOTFOUND) {
+		rc = MDB_SUCCESS;
 	}
-	return 0;
+	return rc;
 }
 
 int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)

libraries/liblmdb/midl.c

@@ -120,8 +120,9 @@ void mdb_midl_free(MDB_IDL ids)
 int mdb_midl_shrink( MDB_IDL *idp )
 {
 	MDB_IDL ids = *idp;
-	if (*(--ids) > MDB_IDL_UM_MAX) {
+	if (*(--ids) > MDB_IDL_UM_MAX &&
-		ids = realloc(ids, (MDB_IDL_UM_MAX+1) * sizeof(MDB_ID));
+		(ids = realloc(ids, (MDB_IDL_UM_MAX+1) * sizeof(MDB_ID))))
+	{
 		*ids++ = MDB_IDL_UM_MAX;
 		*idp = ids;
 		return 1;
@@ -129,7 +130,7 @@ int mdb_midl_shrink( MDB_IDL *idp )
 	return 0;
 }
 
-int mdb_midl_grow( MDB_IDL *idp, int num )
+static int mdb_midl_grow( MDB_IDL *idp, int num )
 {
 	MDB_IDL idn = *idp-1;
 	/* grow it */
@@ -141,6 +142,20 @@ int mdb_midl_grow( MDB_IDL *idp, int num )
 	return 0;
 }
 
+int mdb_midl_need( MDB_IDL *idp, unsigned num )
+{
+	MDB_IDL ids = *idp;
+	num += ids[0];
+	if (num > ids[-1]) {
+		num = (num + num/4 + (256 + 2)) & -256;
+		if (!(ids = realloc(ids-1, num * sizeof(MDB_ID))))
+			return ENOMEM;
+		*ids++ += num -= 2;
+		*idp = ids;
+	}
+	return 0;
+}
+
 int mdb_midl_append( MDB_IDL *idp, MDB_ID id )
 {
 	MDB_IDL ids = *idp;
@@ -169,6 +184,22 @@ int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app )
 	return 0;
 }
 
+int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n )
+{
+	MDB_ID *ids = *idp, len = ids[0];
+	/* Too big? */
+	if (len + n > ids[-1]) {
+		if (mdb_midl_grow(idp, n | MDB_IDL_UM_MAX))
+			return ENOMEM;
+		ids = *idp;
+	}
+	ids[0] = len + n;
+	ids += len;
+	while (n)
+		ids[n--] = id++;
+	return 0;
+}
+
 /* Quicksort + Insertion sort for small arrays */
 
 #define SMALL	8

libraries/liblmdb/midl.h

@@ -68,6 +68,12 @@ typedef MDB_ID *MDB_IDL;
 #define MDB_IDL_FIRST( ids )	( (ids)[1] )
 #define MDB_IDL_LAST( ids )		( (ids)[(ids)[0]] )
 
+	/** Append ID to IDL. The IDL must be big enough. */
+#define mdb_midl_xappend(idl, id) do { \
+		MDB_ID *xidl = (idl), xlen = ++(xidl[0]); \
+		xidl[xlen] = (id); \
+	} while (0)
+
 #if 0	/* superseded by append/sort */
 	/** Insert an ID into an IDL.
 	 * @param[in,out] ids	The IDL to insert into.
@@ -95,28 +101,35 @@ void mdb_midl_free(MDB_IDL ids);
 	 */
 int mdb_midl_shrink(MDB_IDL *idp);
 
-	/** Grow an IDL.
+	/** Make room for num additional elements in an IDL.
-	 * Add room for num additional elements.
+	 * @param[in,out] idp	Address of the IDL.
-	 * @param[in,out] idp	Address of the IDL to grow.
+	 * @param[in] num	Number of elements to make room for.
-	 * @param[in] num	Number of elements to add.
+	 * @return	0 on success, ENOMEM on failure.
-	 * @return	0 on success, -1 on failure.
 	 */
-int mdb_midl_grow(MDB_IDL *idp, int num);
+int mdb_midl_need(MDB_IDL *idp, unsigned num);
 
 	/** Append an ID onto an IDL.
 	 * @param[in,out] idp	Address of the IDL to append to.
 	 * @param[in] id	The ID to append.
-	 * @return	0 on success, -1 if the IDL is too large.
+	 * @return	0 on success, ENOMEM if the IDL is too large.
 	 */
 int mdb_midl_append( MDB_IDL *idp, MDB_ID id );
 
 	/** Append an IDL onto an IDL.
 	 * @param[in,out] idp	Address of the IDL to append to.
 	 * @param[in] app	The IDL to append.
-	 * @return	0 on success, -1 if the IDL is too large.
+	 * @return	0 on success, ENOMEM if the IDL is too large.
 	 */
 int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app );
 
+	/** Append an ID range onto an IDL.
+	 * @param[in,out] idp	Address of the IDL to append to.
+	 * @param[in] id	The lowest ID to append.
+	 * @param[in] n		Number of IDs to append.
+	 * @return	0 on success, ENOMEM if the IDL is too large.
+	 */
+int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n );
+
 	/** Sort an IDL.
 	 * @param[in,out] ids	The IDL to sort.
 	 */