mindspore2022/mindspore/ccsrc/minddata/dataset/api/iterator.cc

104 lines
3.6 KiB
C++

/**
* Copyright 2020 Huawei Technologies Co., Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "minddata/dataset/include/iterator.h"
#include "minddata/dataset/core/client.h"
#include "minddata/dataset/include/datasets.h"
namespace mindspore {
namespace dataset {
namespace api {
// Get the next row from the data pipeline.
void Iterator::GetNextRow(TensorMap *row) {
Status rc = iterator_->GetNextAsMap(row);
if (rc.IsError()) {
MS_LOG(ERROR) << "GetNextRow: Failed to get next row.";
row->clear();
}
}
// Shut down the data pipeline.
void Iterator::Stop() {
// Releasing the iterator_ unique_ptre. This should trigger the destructor of iterator_.
iterator_.reset();
// Release ownership of tree_ shared pointer. This will decrement the ref count.
tree_.reset();
}
// Function to build and launch the execution tree.
Status Iterator::BuildAndLaunchTree(std::shared_ptr<Dataset> ds) {
// One time init
Status rc;
rc = GlobalInit();
RETURN_IF_NOT_OK(rc);
// Instantiate the execution tree
tree_ = std::make_shared<ExecutionTree>();
// Iterative BFS converting Dataset tree into runtime Execution tree.
std::queue<std::pair<std::shared_ptr<Dataset>, std::shared_ptr<DatasetOp>>> q;
if (ds == nullptr) {
RETURN_STATUS_UNEXPECTED("Input is null pointer");
} else {
// Convert the current root node.
auto root_op = ds->Build()->front();
RETURN_UNEXPECTED_IF_NULL(root_op);
RETURN_IF_NOT_OK(tree_->AssociateNode(root_op));
q.push(std::make_pair(ds, root_op));
// Traverse down to the children and convert them to the corresponding DatasetOps (i.e. execution tree nodes)
while (!q.empty()) {
auto node_pair = q.front();
q.pop();
// Iterate through all the direct children of the first element in our BFS queue
for (auto child : node_pair.first->children) {
auto child_ops = child->Build();
RETURN_UNEXPECTED_IF_NULL(child_ops);
auto node_op = node_pair.second;
// Iterate through all the DatasetOps returned by calling Build on the last Dataset object, associate them
// with the execution tree and add the child and parent relationship between the nodes
// Note that some Dataset objects might return more than one DatasetOps
// e.g. MapDataset will return MapOp and ProjectOp if project_columns is set for MapDataset
for (auto child_op : *child_ops) {
RETURN_IF_NOT_OK(tree_->AssociateNode(child_op));
RETURN_IF_NOT_OK(node_op->AddChild(child_op));
node_op = child_op;
}
// Add the child and the last element of the returned DatasetOps (which is now the leaf node in our current
// execution tree) to the BFS queue
q.push(std::make_pair(child, child_ops->back()));
}
}
RETURN_IF_NOT_OK(tree_->AssignRoot(root_op));
}
// Launch the execution tree.
RETURN_IF_NOT_OK(tree_->Prepare());
RETURN_IF_NOT_OK(tree_->Launch());
iterator_ = std::make_unique<DatasetIterator>(tree_);
RETURN_UNEXPECTED_IF_NULL(iterator_);
return rc;
}
} // namespace api
} // namespace dataset
} // namespace mindspore