the low level method htmlelement.classList.add does not accept multiple
classes in one string, which is why, in owl, the expression
`<div t-att-class="{'a b c': value}" />`
did not work as one might expect. It is however very convenient in real
life templates, so this commit improve owl by adding support for this
feature.
closes#813
The initial problem solved by this commit is that it was possible to get
into a situation where a mounting/rendering was started, then the component was
updated, but then another mounting operation begins, and it tries to
reuse the previous rendering operation, which is no longer uptodate.
The underlying issue is that Owl did not track properly the various
internal state change of a component. These issue should be solved by
the introduction of the status enum, which currently tracks 6 possible
states:
- CREATED
- WILLSTARTED
- RENDERED
- MOUNTED
- UNMOUNTED
- DESTROYED
This status number replaces the isMounted and isDestroyed boolean flags.
It has the advantage of making sure that the component is in a
consistent state (it is no longer possible to be destroyed and mounted,
for example)
Another advantage is that it gives us an easy way to track the fact that
a component has been rendered, but is not in the DOM. This is a subtle
situation where some various events can happen, and we need to be able
to react to that case.
Note that there is a change of behaviour: if a component is mounted in a
specific target, then before the mounting is complete, the component is
mounted in another target, we no longer reject the first mounting
operation.
From the beginning, Owl was designed to only call event handler on
components that are mounted in the DOM. The main benefit is that if a
component is destroyed, we are guaranteed to not execute any useless (or
potentially dangerous code).
However, there is one downside: if a component tree is being mounted,
and a child component trigger an event in its mounted hook, then it
cannot be caught by the parent, since the parent is technically not yet
mounted.
This may not be a good situation, but the point is that Owl
unnecessarily prevent the handler to be called.
We can fix this issue by simply checking if the component is not destroyed
instead of checking that it is mounted.
closes#809
Strangely, the _compile method required a CompilationContext whenever it
was compiled as a sub template, but this parent context was actually not
really needed. I guess that it was the case in the past, but this was
changed at some point.
This commit makes another significant change: the xml element is no
longer mandatory. It is actually only required for slots (because the
template is not registered to qweb).
Finally, the interface for the whole method has been changed to use an
option object, which makes more sense with 3 optional paremeters.
While it is not tested, nor documented, the reference QWeb
implementation display the `false` value as "false". So, we have to
adapt the Owl implementation to match that behaviour.
At the same time, this commit uses 'let' instead of 'var' in various places,
to make the compiled code more consistant.
Before this commit, the handlers were bound to the current context,
which is often the component but not necessarily. In some cases, a sub
scope can be created (with t-foreach, or slots, or t-call), and the
context is actually an object with the actual component instance it its
prototype chain, but not the component.
- In some cases, we can simply inline a template key instead of assigning
it to a variable and then using that variable
- Add component name in generated code for components
This commit is a significant refactoring of the internal of QWeb. It
simplifies the way variables/scoping and slots interact together. The
main idea is that we use a simple scope object instead of a
context/var/scope object.
This commit also implement the actual correct QWeb semantic for the
t-call directive with a sub body. Before, we simply extracted the
variables from the body and injected them at the top of the sub
template. We now simply compile the body before the sub template.
This is a joint work with Lucas (lpe).
closes#541closes#544closes#545closes#557closes#556
This is a really interesting problem: there was a situation where a
component would not have an event handler properly bound. The reason was
that we were in a situation where the scheduler task queue was flushed
at an unfortunate timing:
- parent component template is rendered
- subcomponent is prepared:
- sub component is willStarted
- it is rendered (so, fiber counter is set to 0)
- scheduler task queue is flushed => we patch the DOM
- the code registered in the __prepare.then(handler) is executed, which
add the createHook to the vnode (but after the dom is patched)
Usually, the last two steps happen in a different order, but in an
environment with connected components, we sometimes flush the task queue
at various moments, so some code could be executed between the end of
__prepare and the registered handler.
The fix is interesting: we give a callback to the __prepare function
instead of registering a .then handler to the deferred. This callback
is then guaranteed to be called at exactly the proper timing.
Thanks seb for the hard work of finding the root cause of this issue
closes#520
Géry Debongnie