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diff --git a/www/wiki/docs/design.txt b/www/wiki/docs/design.txt new file mode 100644 index 00000000..5c04adde --- /dev/null +++ b/www/wiki/docs/design.txt @@ -0,0 +1,106 @@ +design.txt + +This is a brief overview of the new design. + +More thorough and up-to-date information is available on the documentation +wiki at https://www.mediawiki.org/ + +Primary classes: + + User + Encapsulates the state of the user viewing/using the site. Can be queried + for things like the user's settings, name, etc. Handles the details of + getting and saving to the "user" table of the database, and dealing with + sessions and cookies. + + OutputPage + Encapsulates the entire HTML page that will be sent in response to any + server request. It is used by calling its functions to add text, headers, + etc., in any order, and then calling output() to send it all. It could be + easily changed to send incrementally if that becomes useful, but I prefer + the flexibility. This should also do the output encoding. The system + allocates a global one in $wgOut. + + Title + Represents the title of an article, and does all the work of translating + among various forms such as plain text, URL, database key, etc. For + convenience, and for historical reasons, it also represents a few features + of articles that don't involve their text, such as access rights. + See also title.txt. + + Article + Encapsulates access to the "page" table of the database. The object + represents a an article, and maintains state such as text (in Wikitext + format), flags, etc. + + Revision + Encapsulates individual page revision data and access to the + revision/text/blobs storage system. Higher-level code should never touch + text storage directly; this class mediates it. + + Skin + Encapsulates a "look and feel" for the wiki. All of the functions that + render HTML, and make choices about how to render it, are here, and are + called from various other places when needed (most notably, + OutputPage::addWikiText()). The StandardSkin object is a complete + implementation, and is meant to be subclassed with other skins that may + override some of its functions. The User object contains a reference to a + skin (according to that user's preference), and so rather than having a + global skin object we just rely on the global User and get the skin with + $wgUser->getSkin(). + See also skin.txt. + + Language + Represents the language used for incidental text, and also has some + character encoding functions and other locale stuff. The current user + interface language is instantiated as $wgLang, and the local content + language as $wgContLang; be sure to use the *correct* language object + depending upon the circumstances. + See also language.txt. + + Parser + Class used to transform wikitext to html. + + LinkCache + Keeps information on existence of articles. See linkcache.txt. + +Naming/coding conventions: + + These are meant to be descriptive, not dictatorial; I won't presume to tell + you how to program, I'm just describing the methods I chose to use for myself. + If you do choose to follow these guidelines, it will probably be easier for + you to collaborate with others on the project, but if you want to contribute + without bothering, by all means do so (and don't be surprised if I reformat + your code). + + - I have the code indented with tabs to save file size and so that users can + set their tab stops to any depth they like. I use 4-space tab stops, which + work well. I also use K&R brace matching style. I know that's a religious + issue for some, so if you want to use a style that puts opening braces on + the next line, that's OK too, but please don't use a style where closing + braces don't align with either the opening brace on its own line or the + statement that opened the block--that's confusing as hell. + + - Certain functions and class members are marked with /* private */, rather + than being marked as such. This is a hold-over from PHP 4, which didn't + support proper visibilities. You should not access things marked in this + manner outside the class/inheritance line as this code is subjected to be + updated in a manner that enforces this at some time in the near future, and + things will break. New code should use the standard method of setting + visibilities as normal. + + - Globals are particularly evil in PHP; it sets a lot of them automatically + from cookies, query strings, and such, leading to namespace conflicts; when + a variable name is used in a function, it is silently declared as a new + local masking the global, so you'll get weird error because you forgot the + global declaration; lack of static class member variables means you have to + use globals for them, etc. Evil, evil. + + I think I've managed to pare down the number of globals we use to a scant + few dozen or so, and I've prefixed them all with "wg" so you can spot errors + better (odds are, if you see a "wg" variable being used in a function that + doesn't declare it global, that's probably an error). + + Other conventions: Top-level functions are wfFuncname(), names of session + variables are wsName, cookies wcName, and form field values wpName ("p" for + "POST"). |