Add StatefulErrorReporter and make error_reporter() public from Interpreter API.

PiperOrigin-RevId: 335505537
Change-Id: Ic48a841ca1ace3d664969baa12a9b2e7681a3bb3

tensorflow/lite/BUILD

@@ -669,6 +669,12 @@ cc_library(
     hdrs = ["core/macros.h"],
 )
 
+cc_library(
+    name = "stateful_error_reporter",
+    hdrs = ["stateful_error_reporter.h"],
+    deps = ["//tensorflow/lite/core/api"],
+)
+
 # Shared lib target for convenience, pulls in the core runtime and builtin ops.
 # Note: This target is not yet finalized, and the exact set of exported (C/C++)
 # APIs is subject to change. The output library name is platform dependent:

tensorflow/lite/interpreter.h

@@ -576,6 +576,11 @@ class Interpreter {
   const Subgraph& primary_subgraph() const {
     return *subgraphs_.front();  // Safe as subgraphs_ always has 1 entry.
   }
+
+  /// WARNING: Experimental interface, subject to change
+  // Get the error reporter associated with this interpreter.
+  ErrorReporter* error_reporter() const { return error_reporter_; }
+
 #endif  // DOXYGEN_SKIP
 
  private:
@@ -602,9 +607,6 @@ class Interpreter {
   // Returns true if cancellation function returns true.
   bool IsCancelled();
 
-  // Get the error reporter associated with this interpreter.
-  ErrorReporter* error_reporter() { return error_reporter_; }
-
   // A pure C data structure used to communicate with the pure C plugin
   // interface. To avoid copying tensor metadata, this is also the definitive
   // structure to store tensors.

tensorflow/lite/python/interpreter_wrapper/BUILD

@@ -46,7 +46,7 @@ cc_library(
     srcs = ["python_error_reporter.cc"],
     hdrs = ["python_error_reporter.h"],
     deps = [
-        "//tensorflow/lite/core/api",
+        "//tensorflow/lite:stateful_error_reporter",
         "//third_party/python_runtime:headers",  # buildcleaner: keep
     ],
 )

tensorflow/lite/python/interpreter_wrapper/python_error_reporter.h

@@ -21,12 +21,12 @@ limitations under the License.
 #include <sstream>
 #include <string>
 
-#include "tensorflow/lite/core/api/error_reporter.h"
+#include "tensorflow/lite/stateful_error_reporter.h"
 
 namespace tflite {
 namespace interpreter_wrapper {
 
-class PythonErrorReporter : public tflite::ErrorReporter {
+class PythonErrorReporter : public tflite::StatefulErrorReporter {
  public:
   PythonErrorReporter() {}
 
@@ -38,7 +38,7 @@ class PythonErrorReporter : public tflite::ErrorReporter {
   PyObject* exception();
 
   // Gets the last error message and clears the buffer.
-  std::string message();
+  std::string message() override;
 
  private:
   std::stringstream buffer_;

tensorflow/lite/stateful_error_reporter.h

@@ -0,0 +1,34 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+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.
+==============================================================================*/
+#ifndef TENSORFLOW_LITE_STATEFUL_ERROR_REPORTER_H_
+#define TENSORFLOW_LITE_STATEFUL_ERROR_REPORTER_H_
+
+#include <string>
+
+#include "tensorflow/lite/core/api/error_reporter.h"
+
+namespace tflite {
+
+// Similar to tflite::ErrorReporter, except that it allows callers to get the
+// last error message.
+class StatefulErrorReporter : public ErrorReporter {
+ public:
+  // Returns last error message. Returns empty string if no error is reported.
+  virtual std::string message() = 0;
+};
+
+}  // namespace tflite
+
+#endif  // TENSORFLOW_LITE_STATEFUL_ERROR_REPORTER_H_