!12295 Fix Dataset cache problem after cleanup

From: @hfarahat
Reviewed-by: @robingrosman,@nsyca
Signed-off-by: @robingrosman

mindspore/ccsrc/minddata/dataset/api/python/bindings/dataset/include/datasets_bindings.cc

@@ -87,9 +87,8 @@ PYBIND_REGISTER(DatasetNode, 1, ([](const py::module *m) {
                            return num_workers ? self->SetNumWorkers(*num_workers) : self;
                          })
                     .def("set_cache_client",
-                         [](std::shared_ptr<DatasetNode> self) {
-                           std::shared_ptr<DatasetCache> dc = nullptr;
-                           return self->SetDatasetCache(dc);
+                         [](std::shared_ptr<DatasetNode> self, std::shared_ptr<CacheClient> cc) {
+                           return self->SetDatasetCache(toDatasetCache(std::move(cc)));
                          })
                     .def(
                       "Zip",

mindspore/dataset/engine/datasets.py

@@ -3472,7 +3472,7 @@ class GeneratorDataset(MappableDataset):
                 new_op.sampler = None
                 new_op.sample_fn = sample_fn
                 new_op.source_len = min(new_op.source_len,
-                                        new_op.num_samples) if new_op.num_samples is not None else new_op.source_len
+                                        new_op.num_samples) if new_op.num_samples != 0 else new_op.source_len
                 iter(self.source)
             except TypeError:
                 # Use generator function if input callable