Opsi's SoC 2006

In my last post I spoke about the basic format of .desktop files. If you remember, this files where composed of two elements, one the category header and the other key/value pairs that holded multiple information about the associated Desktop Entry. Specification includes means to localize certain keys in the file so it may contain information to be shown to the user (i.e. name, description,...) that must be localized, this are the keys wich value type is declared as localestring. The approach is easy, we have one "primary" key that holds the default localized value (normally in english) and then add more keys with the same name suffixed with the corresponding POSIX locale in brackets. For example we should have the key Name=Menu Editor with the keys Name[ca]=Editor del menú Name[cs]=Editor nabídky Name[cy]=Golygydd Dewislen Name[da]=Menuredigering following it. If the current locale is not found in the file, the default key must be used. The way this entries are encoded (ISO-8859-1, UTF-8,...) comes defined in the .desktop file using the Encoding required key. This key can take two possible values : UTF-8 of Legacy-Mixed. While the later is deprecated, it's still possible to find it (I think) in some systems, so let's see how it works. When the Legacy-Mixed mode is active for a file, localized keys are encoded using old style encoding (ie not UTF-8). In this files the POSIX Locale that's used to identify each localized key is used to determine the encoding. Following table shows what encodings correspond to each Locale :

( Table directly copied from the standard )

Encodings that are marked with an asterisk are very rare and are not supported by the GNU C library, so maybe they are neither supported by Java. Anyway, as they are so rare and the legacy mode is to be extincted it doesn't look like a problem to really care about.

The .desktop files are the basic entities that are used to build the desktop and the menu in freedesktop.org specification. These are plain text files with "group" headers of the form [GROUP_NAME], where delimiters [ and ] obviusly cannot be contained within GROUP_NAME, and pairs of keys and values with different meanings and restrictions that we'll see in another posts. All the pairs found right after a group header belongs to this group, so pairs are categorized in each desktop entry. Every valid .desktop file must start with the same group, namely [Desktop Entry]. The specification includes also classical bash-style comments (lines starting with #) that are to be ignored by implementations. Specs also indicate that implementations must ignore and preserve items they can't handle, wich gives us the posibility of adding some homegrown properties for the files (Z-Depth, DefaultIconAnimation...), we'll see later on. Each key/value, so called entry, in the file should have the format: Key=Value With spaces trimmed from the beginning and the end of the Key and the Value, and using = as delimiter (can't be used inside a key/value). There are some escape sequences supported in the entries: \s (space), \n (newline), \t (tabulator), \r (carriage return) and \\ (backslash). Some keys can have multiple values that should be separated by a semicolon, and ended by one ; also. To put a semicolon in a single value it has to be escaped \; . Value types are constrained to : string, localestring, regexp, boolean (true/false) and numeric values, from which the strings are ASCII characters and localestring are UTF-8 encoded values (except if something called Legacy-Mixed Encoding is enabled, but we'll talk about it in another post). Later more

Well, I have finally been accepted for the Google's Summer of Code 2006 to create an implementation of the freedesktop standards for menu&desktop regeneration into the Project Looking Glass (You can take a look at my proposal here). First I would like to thank all guys at LG3D that considered me good enough to work with them once again (I also participated in last year's SoC), so Hideya, Deron, Paul, Krishna, Radek and whoever participated in ranking: This goes also to Google itself and to all people there that are so patient with hot-young-hormones (namely,at least, Chris DiBona, Greg Stein and Leslie Hawthorn) PS: Expect some updates soon in this blog