ruby : support new-segment callback (#2506)

* Add Params#new_segment_callback= method

* Add tests for Params#new_segment_callback=

* Group tests for #transcribe

* Don't use static for thread-safety

* Set new_segment_callback only when necessary

* Remove redundant check

* [skip ci] Add Ruby version README

* Revert "Group tests for #transcribe"

This reverts commit 71b65b00cc.

* Revert "Add tests for Params#new_segment_callback="

This reverts commit 81e6df3bab.

* Add test for Context#full_n_segments

* Add Context#full_n_segments

* Add tests for lang API

* Add lang API

* Add tests for Context#full_lang_id API

* Add Context#full_lang_id

* Add abnormal test cases for lang

* Raise appropriate errors from lang APIs

* Add tests for Context#full_get_segment_t{0,1} API

* Add Context#full_get_segment_t{0,1}

* Add tests for Context#full_get_segment_speaker_turn_next API

* Add Context#full_get_segment_speaker_turn_next

* Add tests for Context#full_get_segment_text

* Add Context#full_get_setgment_text

* Add tests for Params#new_segment_callback=

* Run new segment callback

* Split tests to multiple files

* Use container struct for new segment callback

* Add tests for Params#new_segment_callback_user_data=

* Add Whisper::Params#new_user_callback_user_data=

* Add GC-related test for new segment callback

* Protect new segment callback related structs from GC

* Add meaningful test for build

* Rename: new_segment_callback_user_data -> new_segment_callback_container

* Add tests for Whisper::Segment

* Add Whisper::Segment and Whisper::Context#each_segment

* Extract c_ruby_whisper_callback_container_allocate()

* Add test for Whisper::Params#on_new_segment

* Add Whisper::Params#on_new_egment

* Assign symbol IDs to variables

* Make extsources.yaml simpler

* Update README

* Add document comments

* Add test for calling Whisper::Params#on_new_segment multiple times

* Add file dependencies to GitHub actions config and .gitignore

* Add more files to ext/.gitignore

bindings/ruby/README.md

@@ -0,0 +1,110 @@
+whispercpp
+==========
+
+![whisper.cpp](https://user-images.githubusercontent.com/1991296/235238348-05d0f6a4-da44-4900-a1de-d0707e75b763.jpeg)
+
+Ruby bindings for [whisper.cpp][], an interface of automatic speech recognition model.
+
+Installation
+------------
+
+Install the gem and add to the application's Gemfile by executing:
+
+    $ bundle add whispercpp
+
+If bundler is not being used to manage dependencies, install the gem by executing:
+
+    $ gem install whispercpp
+
+Usage
+-----
+
+```ruby
+require "whisper"
+
+whisper = Whisper::Context.new("path/to/model.bin")
+
+params = Whisper::Params.new
+params.language = "en"
+params.offset = 10_000
+params.duration = 60_000
+params.max_text_tokens = 300
+params.translate = true
+params.print_timestamps = false
+
+whisper.transcribe("path/to/audio.wav", params) do |whole_text|
+  puts whole_text
+end
+
+```
+
+### Preparing model ###
+
+Use script to download model file(s):
+
+```bash
+git clone https://github.com/ggerganov/whisper.cpp.git
+cd whisper.cpp
+sh ./models/download-ggml-model.sh base.en
+```
+
+There are some types of models. See [models][] page for details.
+
+### Preparing audio file ###
+
+Currently, whisper.cpp accepts only 16-bit WAV files.
+
+### API ###
+
+Once `Whisper::Context#transcribe` called, you can retrieve segments by `#each_segment`:
+
+```ruby
+def format_time(time_ms)
+  sec, decimal_part = time_ms.divmod(1000)
+  min, sec = sec.divmod(60)
+  hour, min = min.divmod(60)
+  "%02d:%02d:%02d.%03d" % [hour, min, sec, decimal_part]
+end
+
+whisper.transcribe("path/to/audio.wav", params)
+
+whisper.each_segment.with_index do |segment, index|
+  line = "[%{nth}: %{st} --> %{ed}] %{text}" % {
+    nth: index + 1,
+    st: format_time(segment.start_time),
+    ed: format_time(segment.end_time),
+    text: segment.text
+  }
+  line << " (speaker turned)" if segment.speaker_next_turn?
+  puts line
+end
+
+```
+
+You can also add hook to params called on new segment:
+
+```ruby
+def format_time(time_ms)
+  sec, decimal_part = time_ms.divmod(1000)
+  min, sec = sec.divmod(60)
+  hour, min = min.divmod(60)
+  "%02d:%02d:%02d.%03d" % [hour, min, sec, decimal_part]
+end
+
+# Add hook before calling #transcribe
+params.on_new_segment do |segment|
+  line = "[%{st} --> %{ed}] %{text}" % {
+    st: format_time(segment.start_time),
+    ed: format_time(segment.end_time),
+    text: segment.text
+  }
+  line << " (speaker turned)" if segment.speaker_next_turn?
+  puts line
+end
+
+whisper.transcribe("path/to/audio.wav", params)
+
+```
+
+[whisper.cpp]: https://github.com/ggerganov/whisper.cpp
+[models]: https://github.com/ggerganov/whisper.cpp/tree/master/models