limitations under the License.
==============================================================================*/

#include <stddef.h>

#include "tensorflow/c/experimental/saved_model/core/concrete_function.h"
#include "tensorflow/c/experimental/saved_model/internal/concrete_function_list_type.h"
#include "tensorflow/c/experimental/saved_model/internal/concrete_function_type.h"

extern "C" {

# TensorFlow Saved Model C API

## Small ConcreteFunction Example

The following example loads a saved model from `"/path/to/model"` and
executes a function `f` taking no arguments and returning one single
value (error checking is omitted for simplicity):

```c
TF_Status* status = TF_NewStatus();
TFE_ContextOptions* ctx_options = TFE_NewContextOptions();
TFE_Context* ctx = TFE_NewContext(ctx_options, status);

#define TENSORFLOW_C_EXPERIMENTAL_SAVED_MODEL_PUBLIC_C_SAVED_MODEL_API_H_

// IWYU pragma: begin_exports
#include "tensorflow/c/experimental/saved_model/public/concrete_function.h"
#include "tensorflow/c/experimental/saved_model/public/concrete_function_list.h"
#include "tensorflow/c/experimental/saved_model/public/function_metadata.h"

#include "tensorflow/c/experimental/saved_model/public/signature_def_param.h"

#ifdef __cplusplus
extern "C" {
#endif  // __cplusplus

// An opaque type that containing metadata of an input/output of a
// ConcreteFunction loaded from a SavedModel.
typedef struct TF_SignatureDefParamList TF_SignatureDefParamList;

// Returns the size of `list`.
TF_CAPI_EXPORT extern size_t TF_SignatureDefParamListSize(

  // of the inputs and outputs of a function.
  // Note(bmzhao): saved_concrete_func_ is guaranteed to be non-null.
  const SavedConcreteFunction* saved_concrete_func;

  // This field is only present on TF2 ConcreteFunctions, and is useful for
  // determining the original argument *names* of the function, (since the
  // "canonicalized_input_signature" may append extra uniquifying integers).

// A common interface for objects that can be converted to a TensorHandle.
// Examples of objects that implement this include Variables, Constants, Assets,
// etc. This is used to convert captured objects into a ConcreteFunction's
// captured TensorHandles:
// https://github.com/tensorflow/tensorflow/blob/676a68963ea4b64fe479b9cede06aa8f5b290ab8/tensorflow/python/saved_model/load.py#L229-L240
class TensorHandleConvertible {
 public:

implementation.

Its role is to:

1. implement the C API functions declared in `saved_model/public`

2. define the C API types declared in `saved_model/public`

The files fulfilling 1. are named `*.cc` (eg: `concrete_function.cc`), while
the files fulfilling 2. are `*type.h` (eg: `concrete_function_type.h`).

The headers exposing the internal implementation of the opaque C types are only

#include "tensorflow/c/experimental/saved_model/core/tf_saved_model_api.h"
#include "tensorflow/c/experimental/saved_model/internal/saved_model_api_type.h"
#include "tensorflow/c/experimental/saved_model/public/concrete_function.h"
#include "tensorflow/c/experimental/saved_model/public/signature_def_function.h"
#include "tensorflow/c/experimental/saved_model/public/signature_def_function_metadata.h"

namespace tensorflow {

// This is the TF eager runtime implementation of SignatureDefFunction (separate
// from the TFRT implementation). The user-facing API of SignatureDefFunctions
// and their semantic differences from ConcreteFunction are described here:
// https://github.com/tensorflow/tensorflow/blob/e2db60c9d9598ebae0b7741587ce6f5d473584d9/tensorflow/cc/saved_model/experimental/public/signature_def_function.h#L30-L59

  // TODO(bmzhao): Change this to expect TF_OK when loading is implemented.
  // That unblocks writing other tests that require a TF_SavedModel*,
  // like loading a ConcreteFunction. This test at least checks that the
  // C API builds and can be minimally run.
  EXPECT_EQ(status.code(), TF_UNIMPLEMENTED);
}

TEST_P(CPPSavedModelAPITest, LoadsSavedModel) {
  Status status;