!1574 fix tfreadop hang

Merge pull request !1574 from yanghaitao/yht_tfreadop_equal_rows_hang_r0.3

mindspore/ccsrc/dataset/engine/datasetops/source/tf_reader_op.cc

@@ -433,11 +433,13 @@ Status TFReaderOp::FillIOBlockShuffle(const std::vector<int64_t> &i_keys) {
   int64_t start_offset = 0;
   int64_t end_offset = 0;
   bool finish = false;
+  bool end_of_epoch = false;
   while (!finish) {
     for (auto it = i_keys.begin(); it != i_keys.end(); ++it) {
       {
         std::unique_lock<std::mutex> lock(load_io_block_queue_mutex_);
         if (load_io_block_queue_ == false) {
+          end_of_epoch = true;
           break;
         }
       }
@@ -461,7 +463,8 @@ Status TFReaderOp::FillIOBlockShuffle(const std::vector<int64_t> &i_keys) {
         pre_count += filename_numrows_[file_name];
       }
     }
-    if (equal_rows_per_shard_ && pre_count < (static_cast<int64_t>(device_id_) + 1) * num_rows_per_shard_) {
+    if (equal_rows_per_shard_ && pre_count < (static_cast<int64_t>(device_id_) + 1) * num_rows_per_shard_ &&
+        !end_of_epoch) {
       finish = false;
     } else {
       finish = true;
@@ -478,12 +481,14 @@ Status TFReaderOp::FillIOBlockNoShuffle() {
   int64_t start_offset = 0;
   int64_t end_offset = 0;
   bool finish = false;
+  bool end_of_epoch = false;
   while (!finish) {
     // Iterate over all the keys and add one key to each block.
     for (auto it = filename_index_->begin(); it != filename_index_->end(); ++it) {
       {
         std::unique_lock<std::mutex> lock(load_io_block_queue_mutex_);
         if (load_io_block_queue_ == false) {
+          end_of_epoch = true;
           break;
         }
       }
@@ -505,7 +510,8 @@ Status TFReaderOp::FillIOBlockNoShuffle() {
         pre_count += filename_numrows_[file_name];
       }
     }
-    if (equal_rows_per_shard_ && pre_count < (static_cast<int64_t>(device_id_) + 1) * num_rows_per_shard_) {
+    if (equal_rows_per_shard_ && pre_count < (static_cast<int64_t>(device_id_) + 1) * num_rows_per_shard_ &&
+        !end_of_epoch) {
       finish = false;
     } else {
       finish = true;