Merge branch 'dev_reader_shutdown_start' of...

Merge branch 'dev_reader_shutdown_start' of https://github.com/JiayiFeng/Paddle into dev_reader_shutdown_start

paddle/fluid/framework/reader.cc

@@ -39,7 +39,7 @@ void ReaderBase::Start() {
   }
 }
 
-ReaderBase::~ReaderBase() {}
+ReaderBase::~ReaderBase() { Shutdown(); }
 
 }  // namespace framework
 }  // namespace paddle

paddle/fluid/framework/reader.h

@@ -39,9 +39,9 @@ class ReaderBase {
  protected:
   virtual void ReadNextImpl(std::vector<LoDTensor>* out) = 0;
 
-  virtual void ShutdownImpl() = 0;
+  virtual void ShutdownImpl() {}
 
-  virtual void StartImpl() = 0;
+  virtual void StartImpl() {}
 
   ReaderStatus status_{kRunning};
 
@@ -63,15 +63,8 @@ class DecoratedReader : public ReaderBase {
   std::shared_ptr<ReaderBase> reader_;
 };
 
-class FileReader : public ReaderBase {
- public:
-  FileReader() : ReaderBase() {}
-
- protected:
-  void ShutdownImpl() override {}
-
-  void StartImpl() override {}
-};
+// FileReader is just a conceptual class.
+class FileReader : public ReaderBase {};
 
 // The ReaderHolder is used as reader' unified wrapper,
 // making it easier to access different type reader in Variables.

paddle/fluid/operators/reader/create_py_reader_op.cc

@@ -56,8 +56,8 @@ class CreatePyReaderOp : public framework::OperatorBase {
 
     const std::string& queue_name = Input("blocking_queue");
     auto* queue_holder_var = scope.FindVar(queue_name);
-    PADDLE_ENFORCE(
-        queue_holder_var != nullptr,
+    PADDLE_ENFORCE_NOT_NULL(
+        queue_holder_var,
         "No LoDTensorBlockingQueueHolder variable with name %s found",
         queue_name);
     auto* queue_holder =

paddle/fluid/operators/reader/create_recordio_file_reader_op.cc

@@ -22,8 +22,7 @@ template <bool ThreadSafe>
 class RecordIOFileReader : public framework::FileReader {
  public:
   explicit RecordIOFileReader(const std::string& filename)
-      : FileReader(),
-        scanner_(filename),
+      : scanner_(filename),
         dev_ctx_(*platform::DeviceContextPool::Instance().Get(
             platform::CPUPlace())) {
     if (ThreadSafe) {
@@ -42,7 +41,7 @@ class RecordIOFileReader : public framework::FileReader {
     }
   }
 
-  void ShutdownImpl() override { scanner_.Reset(); }
+  void StartImpl() override { scanner_.Reset(); }
 
  private:
   std::unique_ptr<std::mutex> mutex_;