Introduce a new `QtPromise::connect()` helper that allows to create a promise resolved from a single signal and optionally, rejected by another one (from a different object or not). The promise type is determined by the type of the first signal argument (other arguments are currently ignored). A `QPromise<void>` is returned if the resolve signal doesn't provide any argument.
If the rejection is emitted before the promise is resolved, the promise will be rejected with the value of the first argument (other arguments being ignored). If the rejection signal doesn't provide any argument, the promise will be rejected with `QPromiseUndefinedException` if the signal is emitted. Additionally, the promise will be automatically rejected with `QPromiseContextException` if the source object is destroyed before the promise is resolved.
GitBook development seems a bit stuck right now so let's switch to VuePress which, IMO, is more user friendly. Update the documentation to include the version number in which features were added and use custom container to display notes and warnings.
Split the root README.md in multiple Markdown files (in the `docs/` folder) to make easier reading, editing and extending the documentation. An online version is also available on netlify (https://qtpromise.netlify.com). Building it requires Node.js installed, then:
- npm install -g gitbook-cli
- gitbook install ./
- gitbook build . dist/docs
Currently, QPromise can't be added dynamically to QVector (::push_* | ::append) because it doesn't expose a default constructor. Until deciding if a default constructor should be added (private/public?), let's make the `QPromise::all` method work with any container types that are STL compatible.
This method returns a promise that will be fulfilled with the same value as the `input` promise and after at least `msec` milliseconds. If the `input` promise is rejected, the `output` promise is immediately rejected with the same reason.
This `handler` allows to observe the value of the `input` promise, without changing the propagated value. The `output` promise will be resolved with the same value as the `input` promise (the `handler` returned value will be ignored). However, if `handler` throws, `output` is rejected with the new exception. Unlike `finally`, this handler is not called for rejections.
Make QPromise thread safe but also ensure that continuation lambdas (then/fail/finally) are called in the thread of the promise instance they are attached to.
