1 files changed, 31 insertions, 2 deletions
diff --git a/tensorflow/contrib/lite/interpreter.h b/tensorflow/contrib/lite/interpreter.h
index 033b8ee5fa..be149a8cc0 100644
--- a/tensorflow/contrib/lite/interpreter.h
+++ b/tensorflow/contrib/lite/interpreter.h
@@ -63,6 +63,10 @@ template <>
 constexpr TfLiteType typeToTfLiteType<std::complex<float>>() {
   return kTfLiteComplex64;
 }
+template <>
+constexpr TfLiteType typeToTfLiteType<string>() {
+  return kTfLiteString;
+}
 
 // Forward declare since NNAPIDelegate uses Interpreter.
 class NNAPIDelegate;
@@ -107,7 +111,7 @@ class Interpreter {
   // processing this model will be forwarded to the error_reporter object.
   //
   // Note, if error_reporter is nullptr, then a default StderrReporter is
-  // used.
+  // used. Ownership of 'error_reporter' remains with the caller.
   explicit Interpreter(ErrorReporter* error_reporter = DefaultErrorReporter());
 
   ~Interpreter();
@@ -410,6 +414,15 @@ class Interpreter {
   }
 
  private:
+  friend class InterpreterTest;
+
+  // Prevent 'context_' from accessing functions that are only available to
+  // delegated kernels.
+  void SwitchToKernelContext();
+
+  // Add delegate-only functions to 'context_'.
+  void SwitchToDelegateContext();
+
   // Give 'op_reg' a chance to initialize itself using the contents of
   // 'buffer'.
   void* OpInit(const TfLiteRegistration& op_reg, const char* buffer,
@@ -496,6 +509,7 @@ class Interpreter {
   // Update the execution graph to replace some of the nodes with stub
   // nodes. Specifically any node index that has `nodes[index]==1` will be
   // slated for replacement with a delegate kernel specified by registration.
+  // Ownership of 'nodes_to_replace' and 'delegate' remains with the caller.
   // WARNING: This is an experimental interface that is subject to change.
   TfLiteStatus ReplaceSubgraphsWithDelegateKernels(
       TfLiteRegistration registration, const TfLiteIntArray* nodes_to_replace,
@@ -522,6 +536,18 @@ class Interpreter {
   static TfLiteStatus GetExecutionPlan(struct TfLiteContext* context,
                                        TfLiteIntArray** execution_plan);
 
+  // Retrieve an existing external context by type.
+  TfLiteExternalContext* GetExternalContext(TfLiteExternalContextType type);
+  static TfLiteExternalContext* GetExternalContext(
+      struct TfLiteContext* context, TfLiteExternalContextType type);
+
+  // Set the value of an external context.
+  void SetExternalContext(TfLiteExternalContextType type,
+                          TfLiteExternalContext* ctx);
+  static void SetExternalContext(struct TfLiteContext* context,
+                                 TfLiteExternalContextType type,
+                                 TfLiteExternalContext* ctx);
+
   // Ensures that `tensors_` has at least `kTensorsCapacityHeadroom` extra
   // capacity. Calling this function may invalidate existing pointers to
   // tensors. After calling this function, adding `kTensorsCapacityHeadroom`
@@ -611,7 +637,10 @@ class Interpreter {
   bool tensor_resized_since_op_invoke_ = false;
 
   // Profiler for this interpreter instance.
-  profiling::Profiler* profiler_;
+  profiling::Profiler* profiler_ = nullptr;
+
+  // List of active external contexts.
+  TfLiteExternalContext* external_contexts_[kTfLiteMaxExternalContexts];
 };
 
 }  // namespace tflite