If the plugin has successfully been reloaded, return `True`. If it has
not been reloaded for any reason (either an error or because no
modification has been made to it since it has been loaded last), then
return `False`.
Remove the methods and perform the registration/unregistration directly
within the functions that called them. This simplifies the code and
prevents ambiguity between the different functions.
When calling the `reload()` method for `NodePlugins`, we now check that
the timestamp of the node's description file doesn't match with the
timestamp of that same file when the `NodePlugin` was created. If it
does match, then nothing happens during the `reload()`.
Additionnally, add a new error status to distinguish an error during
the registration of the plugin (`LOADING_ERROR`) and an error when
the module itself is reloaded (through the `reload` function from
importlib).
A `NodePlugin` may be part of a `Plugin` even if it has not been
registered. `containsNode` allows to check whether a `NodePlugin` is
contained within a `Plugin`, and `belongsToPlugin`
This prevents ambiguities between `NodePlugin` objects that have been
registered (and are thus instantiable) and those that belong to `Plugin`
objects but have not been registered.
The validation of the node descriptions will be handled directly within
the `NodePlugin` objects and there is thus no need for this method to
exist outside of plugins.py.
A `Plugin` object contains a collection of nodes, represented as
`NodePlugin` objects. This commit adds the implementation of the `Plugin`
class with the methods to add and remove `NodePlugins`, as well as an
empty class for the `NodePlugin` objects themselves.
Add a new module named `plugins` with a `ProcessEnv` class which
contains the paths describing the environment needed for the plugin's
(node's) process.
