Unifex v0.1.1 Unifex.Specs View Source
Module exporting macros that can be used to define Unifex specs.
Example of such specs is provided below:
module Membrane.Element.Mad.Decoder.Native
spec create() :: {:ok :: label, state}
spec decode_frame(payload, offset :: int, state) ::
{:ok :: label, {payload, bytes_used :: long, sample_rate :: long, channels :: int}}
| {:error :: label, :buflen :: label}
| {:error :: label, :malformed :: label}
| {:error :: label, {:recoverable :: label, bytes_to_skip :: int}}
dirty :cpu, decode_frame: 3
sends {:example_msg :: label, number :: int}
According to this specification, module Membrane.Element.Mad.Decoder.Native
should contain 2 functions: create/0
and decode_frame/3
(which is a cpu-bound dirty NIF). The module should use Unifex.Loader
to provide access to
these functions. What is more, messages of the form {:example_msg, integer}
can be sent from the native code to
erlang processes.
The generated boilerplate would require implementation of the following functions:
UNIFEX_TERM create(UnifexEnv* env);
UNIFEX_TERM decode_frame(UnifexEnv* env, UnifexPayload * payload, int offset, State* state);
Also the following functions that should be called to return results will be generated:
UNIFEX_TERM create_result_ok(UnifexEnv* env, State* state);
UNIFEX_TERM decode_frame_result_ok(UnifexEnv* env, UnifexPayload * payload,
long bytes_used, long sample_rate, int channels);
UNIFEX_TERM decode_frame_result_error_buflen(UnifexEnv* env);
UNIFEX_TERM decode_frame_result_error_malformed(UnifexEnv* env);
UNIFEX_TERM decode_frame_result_error_recoverable(UnifexEnv* env, int bytes_to_skip);
See docs for appropriate macros for more details.
Link to this section Summary
Functions
Macro used for marking functions as dirty, i.e. performing long cpu-bound or io-bound operations
Defines module that exports native functions to Elixir world
Defines terms that can be sent from the native code to elixir processes
Defines native function specification
Link to this section Functions
Macro used for marking functions as dirty, i.e. performing long cpu-bound or io-bound operations.
The macro should be used the following way:
dirty type, function1: function1_arity, ...
when type is one of:
:cpu
- marks function as CPU-bound (maps to theERL_NIF_DIRTY_JOB_CPU_BOUND
erlang flag):io
- marks function as IO-bound (maps to theERL_NIF_DIRTY_JOB_IO_BOUND
erlang flag)
Defines module that exports native functions to Elixir world.
The module needs to be defined manually, but it can use
Unifex.Loader
to
have functions declared with spec/1
automatically defined.
Defines terms that can be sent from the native code to elixir processes.
Creates native function that can be invoked to send specified data. Name of the
function starts with send_
and is constructed from label
s.
Defines native function specification.
The specification should be in the form of
spec function_name(parameter1 :: parameter1_type, some_type, parameter3 :: parameter3_type, ...) ::
{:label1 :: label, {result_value1 :: result_value1_type, some_type2, ...}}
| {:label2 :: label, other_result_value2 :: other_result_value2_type}
Parameters
Specs for parameters can either take the form of parameter1 :: parameter1_type
which will generate parameter with name parameter1
of type parameter1_type
The other form - just a name, like some_type
- will generate parameter some_type
of type some_type
.
Custom types can be added by creating modules Unifex.BaseType.Type
that implement
Unifex.BaseType
behaviour. Then, they can by used in specs as type
.
Each generated function gets additional UnifexEnv* env
as the first parameter implicitly.
Returned values
Specs for returned values contain a special type - label
. An atom of type label
will be put literally in returned values by the special function generated for each
spec. Names of the generated functions start with Elixir function name
(e.g. create
) followed by _result_
part and then all the labels joined with _
.
Example
The example is provided in the moduledoc of this module.