Merge pull request #423 from zerebubuth/c_iterate_upper_bound

C iterate upper bound

db/c.cc

@@ -80,7 +80,10 @@ struct rocksdb_writebatch_t      { WriteBatch        rep; };
 struct rocksdb_snapshot_t        { const Snapshot*   rep; };
 struct rocksdb_flushoptions_t    { FlushOptions      rep; };
 struct rocksdb_fifo_compaction_options_t { CompactionOptionsFIFO rep; };
-struct rocksdb_readoptions_t     { ReadOptions       rep; };
+struct rocksdb_readoptions_t {
+   ReadOptions rep;
+   Slice upper_bound; // stack variable to set pointer to in ReadOptions
+};
 struct rocksdb_writeoptions_t    { WriteOptions      rep; };
 struct rocksdb_options_t         { Options           rep; };
 struct rocksdb_block_based_table_options_t  { BlockBasedTableOptions rep; };
@@ -1891,8 +1894,14 @@ void rocksdb_readoptions_set_snapshot(
 void rocksdb_readoptions_set_iterate_upper_bound(
     rocksdb_readoptions_t* opt,
     const char* key, size_t keylen) {
-  Slice prefix = Slice(key, keylen);
-  opt->rep.iterate_upper_bound = &prefix;
+  if (key == nullptr) {
+    opt->upper_bound = Slice();
+    opt->rep.iterate_upper_bound = nullptr;
+
+  } else {
+    opt->upper_bound = Slice(key, keylen);
+    opt->rep.iterate_upper_bound = &opt->upper_bound;
+  }
 }
 
 void rocksdb_readoptions_set_read_tier(

db/c_test.c

@@ -823,6 +823,66 @@ int main(int argc, char** argv) {
     rocksdb_cuckoo_options_destroy(cuckoo_options);
   }
 
+  StartPhase("iterate_upper_bound");
+  {
+    // Create new empty database
+    rocksdb_close(db);
+    rocksdb_destroy_db(options, dbname, &err);
+    CheckNoError(err);
+
+    rocksdb_options_set_prefix_extractor(options, NULL);
+    db = rocksdb_open(options, dbname, &err);
+    CheckNoError(err);
+
+    rocksdb_put(db, woptions, "a",    1, "0",    1, &err); CheckNoError(err);
+    rocksdb_put(db, woptions, "foo",  3, "bar",  3, &err); CheckNoError(err);
+    rocksdb_put(db, woptions, "foo1", 4, "bar1", 4, &err); CheckNoError(err);
+    rocksdb_put(db, woptions, "g1",   2, "0",    1, &err); CheckNoError(err);
+
+    // testing basic case with no iterate_upper_bound and no prefix_extractor
+    {
+       rocksdb_readoptions_set_iterate_upper_bound(roptions, NULL, 0);
+       rocksdb_iterator_t* iter = rocksdb_create_iterator(db, roptions);
+
+       rocksdb_iter_seek(iter, "foo", 3);
+       CheckCondition(rocksdb_iter_valid(iter));
+       CheckIter(iter, "foo", "bar");
+
+       rocksdb_iter_next(iter);
+       CheckCondition(rocksdb_iter_valid(iter));
+       CheckIter(iter, "foo1", "bar1");
+
+       rocksdb_iter_next(iter);
+       CheckCondition(rocksdb_iter_valid(iter));
+       CheckIter(iter, "g1", "0");
+
+       rocksdb_iter_destroy(iter);
+    }
+
+    // testing iterate_upper_bound and forward iterator
+    // to make sure it stops at bound
+    {
+       // iterate_upper_bound points beyond the last expected entry
+       rocksdb_readoptions_set_iterate_upper_bound(roptions, "foo2", 4);
+
+       rocksdb_iterator_t* iter = rocksdb_create_iterator(db, roptions);
+
+       rocksdb_iter_seek(iter, "foo", 3);
+       CheckCondition(rocksdb_iter_valid(iter));
+       CheckIter(iter, "foo", "bar");
+
+       rocksdb_iter_next(iter);
+       CheckCondition(rocksdb_iter_valid(iter));
+       CheckIter(iter, "foo1", "bar1");
+
+       rocksdb_iter_next(iter);
+       // should stop here...
+       CheckCondition(!rocksdb_iter_valid(iter));
+
+       rocksdb_iter_destroy(iter);
+    }
+  }
+
   StartPhase("cleanup");
   rocksdb_close(db);
   rocksdb_options_destroy(options);