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// Copyright 2020 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef ML_SODA_H_
#define ML_SODA_H_
#include <string>
#include <base/no_destructor.h>
#include <base/optional.h>
#include <base/scoped_native_library.h>
#include <chromeos/libsoda/soda_async_impl.h>
namespace ml {
// A singleton proxy class for the soda DSO.
// Usage:
// auto* const soda_library = SodaLibrary::GetInstance();
// if (soda_library->GetStatus() == SodaLibrary::kOk) {
// // Do the real speech recognition here.
// auto soda_instance = soda_library->CreateSodaAsync();
// ...
// } else {
// // Otherwise, use SodaLibrary::GetStatus() to get the error type.
// // Maybe return "not installed".
// ...
// }
class SodaLibrary {
enum class Status {
kOk = 0,
kUninitialized = 1,
kLoadLibraryFailed = 2,
kFunctionLookupFailed = 3,
virtual ~SodaLibrary() = default;
static SodaLibrary* GetInstance();
static SodaLibrary* GetInstanceAt(const std::string& library_path);
// Get whether the library is successfully initialized.
// Initially, the status is `Status::kUninitialized` (this value should never
// be returned).
// If can not be loaded, return `kLoadLibraryFailed`. This
// usually means on-device speech recognition is not supported.
// If the functions can not be successfully looked up, return
// `kFunctionLookupFailed`.
// Return `Status::kOk` if everything works fine.
Status GetStatus() const;
// The following public member functions define the interface functions of
// the library.
// Creates and returns a handle of a soda instance which is needed for using
// the other interfaces. This function will return `NULL` when soda is not
// supported.
// The memory is owned by the user and should be deleted using
// `DeleteSodaAsync` after usage. For the content of config please see
// comments of `SodaConfig` in the file "soda_async_impl.h" installed.
void* CreateSodaAsync(const SodaConfig& config) const;
// Feeds raw audio to soda in the form of a contiguous stream of characters.
// The memory `audio_buffer` is owned by the caller.
void AddAudio(void* soda_async_handle,
const char* audio_buffer,
int audio_buffer_size) const;
void AddAudio(void* soda_async_handle, const std::string& audio_buffer) const;
// Destroys the instance of soda, called on the destruction of the
// SodaAsyncWrapper.
void DeleteSodaAsync(void* soda_async_handle) const;
// The extended version APIs
void* CreateExtendedSodaAsync(const ExtendedSodaConfig& config) const;
void DeleteExtendedSodaAsync(void* extended_soda_async_handle) const;
void ExtendedAddAudio(void* extended_soda_async_handle,
const std::string& audio) const;
void ExtendedSodaStop(void* extended_soda_async_handle) const;
void ExtendedSodaStart(void* extended_soda_async_handle) const;
void ExtendedSodaMarkDone(void* extended_soda_async_handle) const;
friend class base::NoDestructor<SodaLibrary>;
// Initializes the soda library.
explicit SodaLibrary(const std::string& library_path);
SodaLibrary(const SodaLibrary&) = delete;
SodaLibrary& operator=(const SodaLibrary&) = delete;
base::Optional<base::ScopedNativeLibrary> library_;
Status status_;
// These pointers are used to store the "simple" interface function pointers.
// TODO(robsc): Consider deleting these three function if we do not need them
// in CrOS.
CreateSodaAsyncFn create_soda_async_;
AddAudioFn add_audio_;
DeleteSodaAsyncFn delete_soda_async_;
// These pointers are used to store the "extended" interface function
// pointers. They have more control about when speech starts/stops etc.
CreateExtendedSodaAsyncFn create_extended_soda_async_;
DeleteExtendedSodaAsyncFn delete_extended_soda_async_;
ExtendedAddAudioFn extended_add_audio_;
ExtendedSodaStopFn extended_soda_stop_;
ExtendedSodaStartFn extended_soda_start_;
ExtendedSodaMarkDoneFn extended_soda_mark_done_;
} // namespace ml
#endif // ML_SODA_H_