PowerToys/doc/devdocs/modules/interface.md

# Interface definition

```cpp
class PowertoyModuleIface {
public:
  virtual const wchar_t* get_name() = 0;
  virtual const wchar_t** get_events() = 0;
  virtual bool get_config(wchar_t* buffer, int *buffer_size) = 0;
  virtual void set_config(const wchar_t* config) = 0;
  virtual void call_custom_action(const wchar_t* action) {};
  virtual void enable() = 0;
  virtual void disable() = 0;
  virtual bool is_enabled() = 0;
  virtual void destroy() = 0;
};

typedef PowertoyModuleIface* (__cdecl *powertoy_create_func)();
```

# Runtime logic

The PowerToys runner will, for each PowerToy DLL:
  - load the DLL,
  - call [`powertoy_create()`](#powertoy_create_func) to create the PowerToy.

On the received object, the runner will call:
  - [`get_name()`](#get_name) to get the name of the PowerToy,
  - [`enable()`](#enable) to initialize the PowerToy.

While running, the runner might call the following methods between create_powertoy()
and destroy():
  - [`disable()`](#disable)/[`enable()`](#enable)/[`is_enabled()`](#is_enabled) to change or get the PowerToy's enabled state,
  - [`get_config()`](#get_config) to get the available configuration settings,
  - [`set_config()`](#set_config) to set settings after they have been edited in the Settings editor,
  - [`call_custom_action()`](#call_custom_action) when the user selects a custom action in the Settings editor,

When terminating, the runner will:
  - call [`disable()`](#disable),
  - call [`destroy()`](#destroy) which should free all the memory and delete the PowerToy object,
  - unload the DLL.


# Method definition

This section contains a more detailed description of each of the interface methods.

## powertoy_create_func

```cpp
typedef PowertoyModuleIface* (__cdecl *powertoy_create_func)()
```

Typedef of the factory function that creates the PowerToy object.
Must be exported by the DLL as `powertoy_create()`.

Called by the PowerToys runner to initialize each PowerToy.
It will be called only once before a call to [`destroy()`](#destroy) is made.

The returned PowerToy should be in the disabled state. The runner will call the [`enable()`](#enable) method to start the PowerToy.

In case of errors returns `nullptr`.

## get_name

```cpp
virtual const wchar_t* get_name()
```

Returns the name of the PowerToy, it will be cached by the runner.

## get_config

```
virtual bool get_config(wchar_t* buffer, int *buffer_size)
```

Fills a buffer with the available configuration settings.

If `buffer` is a null pointer or the buffer size is not large enough sets the required buffer size in 'buffer_size' and return false.

Returns true if successful.

## set_config

```cpp
virtual void set_config(const wchar_t* config)
```

After the user has changed the module settings in the Settings editor, the runner calls this method to pass to the module the updated values. It's a good place to save the settings as well.

## call_custom_action

```cpp
  virtual void call_custom_action(const wchar_t* action)
```

Calls a custom action in response to the user pressing the custom action button in the Settings editor.
This can be used to spawn custom editors defined by the PowerToy.

## enable

```cpp
  virtual void enable()
```

Enables the PowerToy.

## disable

```cpp
  virtual void disable()
```

Disables the PowerToy, should free as much memory as possible.

## is_enabled

```cpp
  virtual bool is_enabled() = 0;
```

Returns the PowerToy state.

## destroy

```cpp
  virtual void destroy()
```
Destroy the PowerToy and free all memory.

# Code organization

### [`powertoy_module_interface.h`](/src/modules/interface/powertoy_module_interface.h)
Contains the PowerToys interface definition.