Clean up CTC decoder bynding code (#2092)

Summary: Pull Request resolved: https://github.com/pytorch/audio/pull/2092

Reviewed By: carolineechen

Differential Revision: D33169110

fbshipit-source-id: e422ad93efe50b91f1ac5d572dc82768c1000c05

torchaudio/csrc/decoder/bindings/_decoder.cpp

-/*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT-style license found in
- * https://github.com/flashlight/flashlight/blob/d385b2150872fd7bf106601475d8719a703fe9ee/LICENSE
- */
-
-#include <pybind11/pybind11.h>
-#include <pybind11/stl.h>
-
-#include "torchaudio/csrc/decoder/src/decoder/LexiconDecoder.h"
-#include "torchaudio/csrc/decoder/src/decoder/lm/KenLM.h"
-
-namespace py = pybind11;
-using namespace torchaudio::lib::text;
-using namespace py::literals;
-
-/**
- * Some hackery that lets pybind11 handle shared_ptr<void> (for old LMStatePtr).
- * See: https://github.com/pybind/pybind11/issues/820
- * PYBIND11_MAKE_OPAQUE(std::shared_ptr<void>);
- * and inside PYBIND11_MODULE
- *   py::class_<std::shared_ptr<void>>(m, "encapsulated_data");
- */
-
-namespace {
-
-/**
- * A pybind11 "alias type" for abstract class LM, allowing one to subclass LM
- * with a custom LM defined purely in Python. For those who don't want to build
- * with KenLM, or have their own custom LM implementation.
- * See: https://pybind11.readthedocs.io/en/stable/advanced/classes.html
- *
- * TODO: ensure this works. Last time Jeff tried this there were slicing issues,
- * see https://github.com/pybind/pybind11/issues/1546 for workarounds.
- * This is low-pri since we assume most people can just build with KenLM.
- */
-class PyLM : public LM {
-  using LM::LM;
-
-  // needed for pybind11 or else it won't compile
-  using LMOutput = std::pair<LMStatePtr, float>;
-
-  LMStatePtr start(bool startWithNothing) override {
-    PYBIND11_OVERLOAD_PURE(LMStatePtr, LM, start, startWithNothing);
-  }
-
-  LMOutput score(const LMStatePtr& state, const int usrTokenIdx) override {
-    PYBIND11_OVERLOAD_PURE(LMOutput, LM, score, state, usrTokenIdx);
-  }
-
-  LMOutput finish(const LMStatePtr& state) override {
-    PYBIND11_OVERLOAD_PURE(LMOutput, LM, finish, state);
-  }
-};
-
-/**
- * Using custom python LMState derived from LMState is not working with
- * custom python LM (derived from PyLM) because we need to to custing of LMState
- * in score and finish functions to the derived class
- * (for example vie obj.__class__ = CustomPyLMSTate) which cause the error
- * "TypeError: __class__ assignment: 'CustomPyLMState' deallocator differs
- * from 'flashlight.text.decoder._decoder.LMState'"
- * details see in https://github.com/pybind/pybind11/issues/1640
- * To define custom LM you can introduce map inside LM which maps LMstate to
- * additional state info (shared pointers pointing to the same underlying object
- * will have the same id in python in functions score and finish)
- *
- * ```python
- * from flashlight.lib.text.decoder import LM
- * class MyPyLM(LM):
- *      mapping_states = dict() # store simple additional int for each state
- *
- *      def __init__(self):
- *          LM.__init__(self)
- *
- *       def start(self, start_with_nothing):
- *          state = LMState()
- *          self.mapping_states[state] = 0
- *          return state
- *
- *      def score(self, state, index):
- *          outstate = state.child(index)
- *          if outstate not in self.mapping_states:
- *              self.mapping_states[outstate] = self.mapping_states[state] + 1
- *          return (outstate, -numpy.random.random())
- *
- *      def finish(self, state):
- *          outstate = state.child(-1)
- *          if outstate not in self.mapping_states:
- *              self.mapping_states[outstate] = self.mapping_states[state] + 1
- *          return (outstate, -1)
- *```
- */
-void LexiconDecoder_decodeStep(
-    LexiconDecoder& decoder,
-    uintptr_t emissions,
-    int T,
-    int N) {
-  decoder.decodeStep(reinterpret_cast<const float*>(emissions), T, N);
-}
-
-std::vector<DecodeResult> LexiconDecoder_decode(
-    LexiconDecoder& decoder,
-    uintptr_t emissions,
-    int T,
-    int N) {
-  return decoder.decode(reinterpret_cast<const float*>(emissions), T, N);
-}
-
-} // namespace

torchaudio/csrc/decoder/bindings/_dictionary.cpp

-/*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT-style license found in
- * https://github.com/flashlight/flashlight/blob/d385b2150872fd7bf106601475d8719a703fe9ee/LICENSE
- */
-
-#include <pybind11/pybind11.h>
-#include <pybind11/stl.h>
-
-#include "torchaudio/csrc/decoder/src/dictionary/Dictionary.h"
-#include "torchaudio/csrc/decoder/src/dictionary/Utils.h"
-
-namespace py = pybind11;
-using namespace torchaudio::lib::text;
-using namespace py::literals;
-
-namespace {
-
-void Dictionary_addEntry_0(
-    Dictionary& dict,
-    const std::string& entry,
-    int idx) {
-  dict.addEntry(entry, idx);
-}
-
-void Dictionary_addEntry_1(Dictionary& dict, const std::string& entry) {
-  dict.addEntry(entry);
-}
-
-} // namespace

torchaudio/csrc/decoder/bindings/pybind.cpp

 #include <torch/extension.h>
 
-#include <torchaudio/csrc/decoder/bindings/_decoder.cpp>
-#include <torchaudio/csrc/decoder/bindings/_dictionary.cpp>
+#include "torchaudio/csrc/decoder/src/decoder/LexiconDecoder.h"
+#include "torchaudio/csrc/decoder/src/decoder/lm/KenLM.h"
+#include "torchaudio/csrc/decoder/src/dictionary/Dictionary.h"
+#include "torchaudio/csrc/decoder/src/dictionary/Utils.h"
+
+namespace py = pybind11;
+using namespace torchaudio::lib::text;
+using namespace py::literals;
+
+/**
+ * Some hackery that lets pybind11 handle shared_ptr<void> (for old LMStatePtr).
+ * See: https://github.com/pybind/pybind11/issues/820
+ * PYBIND11_MAKE_OPAQUE(std::shared_ptr<void>);
+ * and inside PYBIND11_MODULE
+ *   py::class_<std::shared_ptr<void>>(m, "encapsulated_data");
+ */
+
+namespace {
+
+/**
+ * A pybind11 "alias type" for abstract class LM, allowing one to subclass LM
+ * with a custom LM defined purely in Python. For those who don't want to build
+ * with KenLM, or have their own custom LM implementation.
+ * See: https://pybind11.readthedocs.io/en/stable/advanced/classes.html
+ *
+ * TODO: ensure this works. Last time Jeff tried this there were slicing issues,
+ * see https://github.com/pybind/pybind11/issues/1546 for workarounds.
+ * This is low-pri since we assume most people can just build with KenLM.
+ */
+class PyLM : public LM {
+  using LM::LM;
+
+  // needed for pybind11 or else it won't compile
+  using LMOutput = std::pair<LMStatePtr, float>;
+
+  LMStatePtr start(bool startWithNothing) override {
+    PYBIND11_OVERLOAD_PURE(LMStatePtr, LM, start, startWithNothing);
+  }
+
+  LMOutput score(const LMStatePtr& state, const int usrTokenIdx) override {
+    PYBIND11_OVERLOAD_PURE(LMOutput, LM, score, state, usrTokenIdx);
+  }
+
+  LMOutput finish(const LMStatePtr& state) override {
+    PYBIND11_OVERLOAD_PURE(LMOutput, LM, finish, state);
+  }
+};
+
+/**
+ * Using custom python LMState derived from LMState is not working with
+ * custom python LM (derived from PyLM) because we need to to custing of LMState
+ * in score and finish functions to the derived class
+ * (for example vie obj.__class__ = CustomPyLMSTate) which cause the error
+ * "TypeError: __class__ assignment: 'CustomPyLMState' deallocator differs
+ * from 'flashlight.text.decoder._decoder.LMState'"
+ * details see in https://github.com/pybind/pybind11/issues/1640
+ * To define custom LM you can introduce map inside LM which maps LMstate to
+ * additional state info (shared pointers pointing to the same underlying object
+ * will have the same id in python in functions score and finish)
+ *
+ * ```python
+ * from flashlight.lib.text.decoder import LM
+ * class MyPyLM(LM):
+ *      mapping_states = dict() # store simple additional int for each state
+ *
+ *      def __init__(self):
+ *          LM.__init__(self)
+ *
+ *       def start(self, start_with_nothing):
+ *          state = LMState()
+ *          self.mapping_states[state] = 0
+ *          return state
+ *
+ *      def score(self, state, index):
+ *          outstate = state.child(index)
+ *          if outstate not in self.mapping_states:
+ *              self.mapping_states[outstate] = self.mapping_states[state] + 1
+ *          return (outstate, -numpy.random.random())
+ *
+ *      def finish(self, state):
+ *          outstate = state.child(-1)
+ *          if outstate not in self.mapping_states:
+ *              self.mapping_states[outstate] = self.mapping_states[state] + 1
+ *          return (outstate, -1)
+ *```
+ */
+void LexiconDecoder_decodeStep(
+    LexiconDecoder& decoder,
+    uintptr_t emissions,
+    int T,
+    int N) {
+  decoder.decodeStep(reinterpret_cast<const float*>(emissions), T, N);
+}
+
+std::vector<DecodeResult> LexiconDecoder_decode(
+    LexiconDecoder& decoder,
+    uintptr_t emissions,
+    int T,
+    int N) {
+  return decoder.decode(reinterpret_cast<const float*>(emissions), T, N);
+}
+
+void Dictionary_addEntry_0(
+    Dictionary& dict,
+    const std::string& entry,
+    int idx) {
+  dict.addEntry(entry, idx);
+}
+
+void Dictionary_addEntry_1(Dictionary& dict, const std::string& entry) {
+  dict.addEntry(entry);
+}
 
 PYBIND11_MODULE(_torchaudio_decoder, m) {
 #ifdef BUILD_CTC_DECODER
@@ -137,3 +247,5 @@ PYBIND11_MODULE(_torchaudio_decoder, m) {
   m.def("_load_words", &loadWords, "filename"_a, "max_words"_a = -1);
 #endif
 }
+
+} // namespace