core/pkgs/build-support/make-desktopitem/default.nix
2024-06-30 09:16:52 +01:00

143 lines
5 KiB
Nix

{
lib,
writeTextFile,
buildPackages,
}:
# All possible values as defined by the spec, version 1.4.
# Please keep in spec order for easier maintenance.
# When adding a new value, don't forget to update the Version field below!
# See https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html
lib.makeOverridable (
{
name, # The name of the desktop file
type ? "Application"
# version is hardcoded
,
desktopName, # The name of the application
genericName ? null,
noDisplay ? null,
comment ? null,
icon ? null,
# we don't support the Hidden key - if you don't need something, just don't install it
onlyShowIn ? [ ],
notShowIn ? [ ],
dbusActivatable ? null,
tryExec ? null,
exec ? null,
path ? null,
terminal ? null,
actions ? { }, # An attrset of [internal name] -> { name, exec?, icon? }
mimeTypes ? [ ], # The spec uses "MimeType" as singular, use plural here to signify list-ness
categories ? [ ],
implements ? [ ],
keywords ? [ ],
startupNotify ? null,
startupWMClass ? null,
url ? null,
prefersNonDefaultGPU ? null,
# not supported until version 1.5, which is not supported by our desktop-file-utils as of 2022-02-23
# , singleMainWindow ? null
extraConfig ? { }, # Additional values to be added literally to the final item, e.g. vendor extensions
}:
let
# There are multiple places in the FDO spec that make "boolean" values actually tristate,
# e.g. StartupNotify, where "unset" is literally defined as "do something reasonable".
# So, handle null values separately.
boolOrNullToString =
value:
if value == null then
null
else if builtins.isBool value then
lib.boolToString value
else
throw "makeDesktopItem: value must be a boolean or null!";
# Multiple values are represented as one string, joined by semicolons.
# Technically, it's possible to escape semicolons in values with \;, but this is currently not implemented.
renderList =
key: value:
if !builtins.isList value then
throw "makeDesktopItem: value for ${key} must be a list!"
else if builtins.any (item: lib.hasInfix ";" item) value then
throw "makeDesktopItem: values in ${key} list must not contain semicolons!"
else if value == [ ] then
null
else
builtins.concatStringsSep ";" value;
# The [Desktop Entry] section of the desktop file, as an attribute set.
# Please keep in spec order.
mainSection = {
"Type" = type;
"Version" = "1.4";
"Name" = desktopName;
"GenericName" = genericName;
"NoDisplay" = boolOrNullToString noDisplay;
"Comment" = comment;
"Icon" = icon;
"OnlyShowIn" = renderList "onlyShowIn" onlyShowIn;
"NotShowIn" = renderList "notShowIn" notShowIn;
"DBusActivatable" = boolOrNullToString dbusActivatable;
"TryExec" = tryExec;
"Exec" = exec;
"Path" = path;
"Terminal" = boolOrNullToString terminal;
"Actions" = renderList "actions" (builtins.attrNames actions);
"MimeType" = renderList "mimeTypes" mimeTypes;
"Categories" = renderList "categories" categories;
"Implements" = renderList "implements" implements;
"Keywords" = renderList "keywords" keywords;
"StartupNotify" = boolOrNullToString startupNotify;
"StartupWMClass" = startupWMClass;
"URL" = url;
"PrefersNonDefaultGPU" = boolOrNullToString prefersNonDefaultGPU;
# "SingleMainWindow" = boolOrNullToString singleMainWindow;
} // extraConfig;
# Render a single attribute pair to a Key=Value line.
# FIXME: this isn't entirely correct for arbitrary strings, as some characters
# need to be escaped. There are currently none in nixpkgs though, so this is OK.
renderLine = name: value: if value != null then "${name}=${value}" else null;
# Render a full section of the file from an attrset.
# Null values are intentionally left out.
renderSection =
sectionName: attrs:
lib.pipe attrs [
(lib.mapAttrsToList renderLine)
(builtins.filter (v: v != null))
(builtins.concatStringsSep "\n")
(section: ''
[${sectionName}]
${section}
'')
];
mainSectionRendered = renderSection "Desktop Entry" mainSection;
# Convert from javaCase names as used in Nix to PascalCase as used in the spec.
preprocessAction =
{
name,
icon ? null,
exec ? null,
}:
{
"Name" = name;
"Icon" = icon;
"Exec" = exec;
};
renderAction = name: attrs: renderSection "Desktop Action ${name}" (preprocessAction attrs);
actionsRendered = lib.mapAttrsToList renderAction actions;
content = [ mainSectionRendered ] ++ actionsRendered;
in
writeTextFile {
name = "${name}.desktop";
destination = "/share/applications/${name}.desktop";
text = builtins.concatStringsSep "\n" content;
checkPhase = ''${buildPackages.desktop-file-utils}/bin/desktop-file-validate "$target"'';
}
)