Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/browser/components/urlbar/docs/lifetime.rst b/browser/components/urlbar/docs/lifetime.rst
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+Search Lifecycle
+================
+
+When a character is typed into the address bar, or the address bar is focused,
+we initiate a search. What follows is a simplified version of the
+lifetime of a search, describing the pipeline that returns results for a typed
+string. Some parts of the query lifetime are intentionally omitted from this
+document for clarity.
+
+The search described in this document is internal to the address bar. It is not
+the search sent to the default search engine when you press Enter. Parts of this
+process often occur multiple times per keystroke, as described below.
+
+It is recommended that you first read the :doc:`nontechnical-overview` to become
+familiar with the terminology in this document. This document is current as
+of December 2021.
+
+#.
+   The user types a query (e.g. "coffee near me") into the *UrlbarInput*
+   `<input> DOM element <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/base/content/browser.xhtml#1864>`_.
+   That DOM element `tells <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarInput.jsm#2919>`_
+   *UrlbarInput* that text is being input.
+
+#.
+   *UrlbarInput* `starts a search <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarInput.jsm#2990>`_.
+   It `creates <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarInput.jsm#1290>`_
+   a `UrlbarQueryContext <https://firefox-source-docs.mozilla.org/browser/urlbar/overview.html#the-urlbarquerycontext>`_
+   and `passes it to UrlbarController <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarInput.jsm#1289>`_.
+   The query context is an object that will exist for the lifetime of the query
+   and it's how we keep track of what results to show. It contains information
+   like what kind of results are allowed, the search string ("coffee near me",
+   in this case), and other information about the state of the Urlbar. A new
+   *UrlbarQueryContext* is created every time the text in the input changes.
+
+#.
+   *UrlbarController* `tells UrlbarProvidersManager <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarController.jsm#134>`_
+   that the providers should fetch results.
+
+#.
+   *UrlbarProvidersManager* tells `each <https://searchfox.org/mozilla-central/source/browser/components/urlbar/UrlbarProvidersManager.jsm#348>`_
+   provider to decide if it wants to provide results for this query by calling
+   their `isActive <https://searchfox.org/mozilla-central/source/browser/components/urlbar/UrlbarProvidersManager.jsm#362>`_
+   methods. The provider can decide whether or not it will be active for this
+   query. Some providers are rarely active: for example,
+   *UrlbarProviderTopSites* `isn't active if the user has typed a search string <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarProviderTopSites.jsm#69>`_.
+
+#.
+   *UrlbarProvidersManager* then tells the *active* providers to fetch results by
+   `calling their startQuery method <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarProvidersManager.jsm#400>`_.
+
+#.
+   The providers fetch results for the query asynchronously. Each provider
+   fetches results in a different way. As one example, if the default search
+   engine is Google, *UrlbarProviderSearchSuggestions* would send the string
+   "coffee near me" to Google. Google would return a list of suggestions and
+   *UrlbarProviderSearchSuggestions* would create a *UrlbarResult* for each one.
+
+#.
+   The providers send their results back to *UrlbarProvidersManager*. They do
+   this one result at a time by `calling the addCallback callback <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarProviderSearchSuggestions.jsm#294>`_
+   passed into startQuery. *UrlbarProvidersManager* takes all the results from all the
+   providers and `puts them into the UrlbarQueryContext <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarProvidersManager.jsm#541>`_.
+
+   Due to the asynchronous and parallel nature of providers, this and the
+   following steps may occur multiple times per search. Some providers may take
+   longer than others to return their results. We don't want to wait for slow
+   providers before showing results. To handle slow providers,
+   *UrlbarProvidersManager* gathers results from providers in "chunks". A timer
+   fires on an internal. Every time the timer fires, we take whatever results we
+   have from the active providers (the "chunk" of results) and perform the
+   following steps.
+
+#.
+   *UrlbarProvidersManager* `asks <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarProvidersManager.jsm#582>`_
+   *UrlbarMuxer* to sort the results.
+
+#.
+   *UrlbarMuxer* chooses the results that will be shown to the user. It groups
+   and sorts the results to determine the order in which the results will be
+   shown. This process usually involves discarding irrelevant and duplicate
+   results. We also cap results at a limit, defined in the
+   ``browser.urlbar.maxRichResults`` preference.
+
+#.
+   Once the results are sorted, *UrlbarProvidersManager*
+   `tells UrlbarController <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarProvidersManager.jsm#627>`_
+   that results are ready to be shown.
+
+#.
+   *UrlbarController* `sends out a notification <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarController.jsm#198>`_
+   that results are ready to be shown. *UrlbarView* was `listening <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarView.jsm#615>`_
+   for that notification. Once the view gets the notification, it `creates <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarView.jsm#623>`__
+   `DOM nodes <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarView.jsm#1003>`_
+   for each *UrlbarResult* and `inserts them <https://searchfox.org/mozilla-central/rev/0bcf81557b89e7757c44e25bb4bc7f4cb8619dc9/browser/components/urlbar/UrlbarView.jsm#989>`_
+   into the view's DOM element.
+
+   As described above, we may reach this step multiple times per search. That
+   means we may be updating the view multiple times per keystroke. A view that
+   visibly changes many times after a single keystroke is perceived as
+   "flickering" by the user. As a result, we try to limit the number of times
+   the view needs to update.
+
+
+   .. figure:: assets/lifetime/lifetime.png
+      :alt: A chart with boxes representing the various components of the
+            address bar. An arrow moves between the boxes to illustrate a query
+            moving through the components.
+      :scale: 80%
+      :align: center