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nixpkgs/pkgs/lib/misc.nix
Vladimír Čunát ec3965d8d0 Revert Merge x-updates into master due to mesa bloat 
See #490 discussion.

This reverts commit 1278859d31, reversing
changes made to 0c020c98f9.

Conflicts:
	pkgs/desktops/xfce/core/xfce4-session.nix (take master)
	pkgs/lib/misc.nix (auto)
2013-05-09 14:03:35 +02:00

429 lines
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Nix
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let lib = import ./default.nix;
inherit (builtins) isFunction hasAttr getAttr head tail isList isAttrs isInt attrNames;
in
with import ./lists.nix;
with import ./attrsets.nix;
with import ./strings.nix;
rec {
# returns default if env var is not set
maybeEnv = name: default:
let value = builtins.getEnv name; in
if value == "" then default else value;
defaultMergeArg = x : y: if builtins.isAttrs y then
y
else
(y x);
defaultMerge = x: y: x // (defaultMergeArg x y);
foldArgs = merger: f: init: x:
let arg=(merger init (defaultMergeArg init x));
# now add the function with composed args already applied to the final attrs
base = (setAttrMerge "passthru" {} (f arg)
( z : z // rec {
function = foldArgs merger f arg;
args = (lib.attrByPath ["passthru" "args"] {} z) // x;
} ));
withStdOverrides = base // {
override = base.passthru.function;
deepOverride = a : (base.passthru.function ((lib.mapAttrs (lib.deepOverrider a) base.passthru.args) // a));
} ;
in
withStdOverrides;
# predecessors: proposed replacement for applyAndFun (which has a bug cause it merges twice)
# the naming "overridableDelayableArgs" tries to express that you can
# - override attr values which have been supplied earlier
# - use attr values before they have been supplied by accessing the fix point
# name "fixed"
# f: the (delayed overridden) arguments are applied to this
#
# initial: initial attrs arguments and settings. see defaultOverridableDelayableArgs
#
# returns: f applied to the arguments // special attributes attrs
# a) merge: merge applied args with new args. Wether an argument is overridden depends on the merge settings
# b) replace: this let's you replace and remove names no matter which merge function has been set
#
# examples: see test cases "res" below;
overridableDelayableArgs =
f : # the function applied to the arguments
initial : # you pass attrs, the functions below are passing a function taking the fix argument
let
takeFixed = if isFunction initial then initial else (fixed : initial); # transform initial to an expression always taking the fixed argument
tidy = args :
let # apply all functions given in "applyPreTidy" in sequence
applyPreTidyFun = fold ( n : a : x : n ( a x ) ) lib.id (maybeAttr "applyPreTidy" [] args);
in removeAttrs (applyPreTidyFun args) ( ["applyPreTidy"] ++ (maybeAttr "removeAttrs" [] args) ); # tidy up args before applying them
fun = n : x :
let newArgs = fixed :
let args = takeFixed fixed;
mergeFun = getAttr n args;
in if isAttrs x then (mergeFun args x)
else assert isFunction x;
mergeFun args (x ( args // { inherit fixed; }));
in overridableDelayableArgs f newArgs;
in
(f (tidy (lib.fix takeFixed))) // {
merge = fun "mergeFun";
replace = fun "keepFun";
};
defaultOverridableDelayableArgs = f :
let defaults = {
mergeFun = mergeAttrByFunc; # default merge function. merge strategie (concatenate lists, strings) is given by mergeAttrBy
keepFun = a : b : { inherit (a) removeAttrs mergeFun keepFun mergeAttrBy; } // b; # even when using replace preserve these values
applyPreTidy = []; # list of functions applied to args before args are tidied up (usage case : prepareDerivationArgs)
mergeAttrBy = mergeAttrBy // {
applyPreTidy = a : b : a ++ b;
removeAttrs = a : b: a ++ b;
};
removeAttrs = ["mergeFun" "keepFun" "mergeAttrBy" "removeAttrs" "fixed" ]; # before applying the arguments to the function make sure these names are gone
};
in (overridableDelayableArgs f defaults).merge;
# rec { # an example of how composedArgsAndFun can be used
# a = composedArgsAndFun (x : x) { a = ["2"]; meta = { d = "bar";}; };
# # meta.d will be lost ! It's your task to preserve it (eg using a merge function)
# b = a.passthru.function { a = [ "3" ]; meta = { d2 = "bar2";}; };
# # instead of passing/ overriding values you can use a merge function:
# c = b.passthru.function ( x: { a = x.a ++ ["4"]; }); # consider using (maybeAttr "a" [] x)
# }
# result:
# {
# a = { a = ["2"]; meta = { d = "bar"; }; passthru = { function = .. }; };
# b = { a = ["3"]; meta = { d2 = "bar2"; }; passthru = { function = .. }; };
# c = { a = ["3" "4"]; meta = { d2 = "bar2"; }; passthru = { function = .. }; };
# # c2 is equal to c
# }
composedArgsAndFun = f: foldArgs defaultMerge f {};
# shortcut for attrByPath ["name"] default attrs
maybeAttrNullable = name: default: attrs:
if attrs == null then default else
if __hasAttr name attrs then (__getAttr name attrs) else default;
# shortcut for attrByPath ["name"] default attrs
maybeAttr = name: default: attrs:
if __hasAttr name attrs then (__getAttr name attrs) else default;
# Return the second argument if the first one is true or the empty version
# of the second argument.
ifEnable = cond: val:
if cond then val
else if builtins.isList val then []
else if builtins.isAttrs val then {}
# else if builtins.isString val then ""
else if val == true || val == false then false
else null;
# Return true only if there is an attribute and it is true.
checkFlag = attrSet: name:
if name == "true" then true else
if name == "false" then false else
if (elem name (attrByPath ["flags"] [] attrSet)) then true else
attrByPath [name] false attrSet ;
# Input : attrSet, [ [name default] ... ], name
# Output : its value or default.
getValue = attrSet: argList: name:
( attrByPath [name] (if checkFlag attrSet name then true else
if argList == [] then null else
let x = builtins.head argList; in
if (head x) == name then
(head (tail x))
else (getValue attrSet
(tail argList) name)) attrSet );
# Input : attrSet, [[name default] ...], [ [flagname reqs..] ... ]
# Output : are reqs satisfied? It's asserted.
checkReqs = attrSet : argList : condList :
(
fold lib.and true
(map (x: let name = (head x) ; in
((checkFlag attrSet name) ->
(fold lib.and true
(map (y: let val=(getValue attrSet argList y); in
(val!=null) && (val!=false))
(tail x))))) condList)) ;
# This function has O(n^2) performance.
uniqList = {inputList, acc ? []} :
let go = xs : acc :
if xs == []
then []
else let x = head xs;
y = if elem x acc then [] else [x];
in y ++ go (tail xs) (y ++ acc);
in go inputList acc;
uniqListExt = {inputList, outputList ? [],
getter ? (x : x), compare ? (x: y: x==y)}:
if inputList == [] then outputList else
let x=head inputList;
isX = y: (compare (getter y) (getter x));
newOutputList = outputList ++
(if any isX outputList then [] else [x]);
in uniqListExt {outputList=newOutputList;
inputList = (tail inputList);
inherit getter compare;
};
condConcat = name: list: checker:
if list == [] then name else
if checker (head list) then
condConcat
(name + (head (tail list)))
(tail (tail list))
checker
else condConcat
name (tail (tail list)) checker;
lazyGenericClosure = {startSet, operator}:
let
work = list: doneKeys: result:
if list == [] then
result
else
let x = head list; key = x.key; in
if elem key doneKeys then
work (tail list) doneKeys result
else
work (tail list ++ operator x) ([key] ++ doneKeys) ([x] ++ result);
in
work startSet [] [];
genericClosure =
if builtins ? genericClosure then builtins.genericClosure
else lazyGenericClosure;
innerModifySumArgs = f: x: a: b: if b == null then (f a b) // x else
innerModifySumArgs f x (a // b);
modifySumArgs = f: x: innerModifySumArgs f x {};
innerClosePropagation = acc : xs :
if xs == []
then acc
else let y = head xs;
ys = tail xs;
in if ! isAttrs y
then innerClosePropagation acc ys
else let acc' = [y] ++ acc;
in innerClosePropagation
acc'
(uniqList { inputList = (maybeAttrNullable "propagatedBuildInputs" [] y)
++ (maybeAttrNullable "propagatedNativeBuildInputs" [] y)
++ ys;
acc = acc';
}
);
closePropagation = list: (uniqList {inputList = (innerClosePropagation [] list);});
# calls a function (f attr value ) for each record item. returns a list
mapAttrsFlatten = f : r : map (attr: f attr (builtins.getAttr attr r) ) (attrNames r);
# attribute set containing one attribute
nvs = name : value : listToAttrs [ (nameValuePair name value) ];
# adds / replaces an attribute of an attribute set
setAttr = set : name : v : set // (nvs name v);
# setAttrMerge (similar to mergeAttrsWithFunc but only merges the values of a particular name)
# setAttrMerge "a" [] { a = [2];} (x : x ++ [3]) -> { a = [2 3]; }
# setAttrMerge "a" [] { } (x : x ++ [3]) -> { a = [ 3]; }
setAttrMerge = name : default : attrs : f :
setAttr attrs name (f (maybeAttr name default attrs));
# Using f = a : b = b the result is similar to //
# merge attributes with custom function handling the case that the attribute
# exists in both sets
mergeAttrsWithFunc = f : set1 : set2 :
fold (n: set : if (__hasAttr n set)
then setAttr set n (f (__getAttr n set) (__getAttr n set2))
else set )
(set2 // set1) (__attrNames set2);
# merging two attribute set concatenating the values of same attribute names
# eg { a = 7; } { a = [ 2 3 ]; } becomes { a = [ 7 2 3 ]; }
mergeAttrsConcatenateValues = mergeAttrsWithFunc ( a : b : (toList a) ++ (toList b) );
# merges attributes using //, if a name exisits in both attributes
# an error will be triggered unless its listed in mergeLists
# so you can mergeAttrsNoOverride { buildInputs = [a]; } { buildInputs = [a]; } {} to get
# { buildInputs = [a b]; }
# merging buildPhase does'nt really make sense. The cases will be rare where appending /prefixing will fit your needs?
# in these cases the first buildPhase will override the second one
# ! deprecated, use mergeAttrByFunc instead
mergeAttrsNoOverride = { mergeLists ? ["buildInputs" "propagatedBuildInputs"],
overrideSnd ? [ "buildPhase" ]
} : attrs1 : attrs2 :
fold (n: set :
setAttr set n ( if (__hasAttr n set)
then # merge
if elem n mergeLists # attribute contains list, merge them by concatenating
then (__getAttr n attrs2) ++ (__getAttr n attrs1)
else if elem n overrideSnd
then __getAttr n attrs1
else throw "error mergeAttrsNoOverride, attribute ${n} given in both attributes - no merge func defined"
else __getAttr n attrs2 # add attribute not existing in attr1
)) attrs1 (__attrNames attrs2);
# example usage:
# mergeAttrByFunc {
# inherit mergeAttrBy; # defined below
# buildInputs = [ a b ];
# } {
# buildInputs = [ c d ];
# };
# will result in
# { mergeAttrsBy = [...]; buildInputs = [ a b c d ]; }
# is used by prepareDerivationArgs, defaultOverridableDelayableArgs and can be used when composing using
# foldArgs, composedArgsAndFun or applyAndFun. Example: composableDerivation in all-packages.nix
mergeAttrByFunc = x : y :
let
mergeAttrBy2 = { mergeAttrBy=lib.mergeAttrs; }
// (maybeAttr "mergeAttrBy" {} x)
// (maybeAttr "mergeAttrBy" {} y); in
fold lib.mergeAttrs {} [
x y
(mapAttrs ( a : v : # merge special names using given functions
if (hasAttr a x)
then if (hasAttr a y)
then v (getAttr a x) (getAttr a y) # both have attr, use merge func
else (getAttr a x) # only x has attr
else (getAttr a y) # only y has attr)
) (removeAttrs mergeAttrBy2
# don't merge attrs which are neither in x nor y
(filter (a : (! hasAttr a x) && (! hasAttr a y) )
(attrNames mergeAttrBy2))
)
)
];
mergeAttrsByFuncDefaults = foldl mergeAttrByFunc { inherit mergeAttrBy; };
# merge attrs based on version key into mkDerivation args, see mergeAttrBy to learn about smart merge defaults
#
# This function is best explained by an example:
#
# {version ? "2.x"} :
#
# mkDerivation (mergeAttrsByVersion "package-name" version
# { # version specific settings
# "git" = { src = ..; preConfigre = "autogen.sh"; buildInputs = [automake autoconf libtool]; };
# "2.x" = { src = ..; };
# }
# { // shared settings
# buildInputs = [ common build inputs ];
# meta = { .. }
# }
# )
#
# Please note that e.g. Eelco Dolstra usually prefers having one file for
# each version. On the other hand there are valuable additional design goals
# - readability
# - do it once only
# - try to avoid duplication
#
# Marc Weber and Michael Raskin sometimes prefer keeping older
# versions around for testing and regression tests - as long as its cheap to
# do so.
#
# Very often it just happens that the "shared" code is the bigger part.
# Then using this function might be appropriate.
#
# Be aware that its easy to cause recompilations in all versions when using
# this function - also if derivations get too complex splitting into multiple
# files is the way to go.
#
# See misc.nix -> versionedDerivation
# discussion: nixpkgs: pull/310
mergeAttrsByVersion = name: version: attrsByVersion: base:
mergeAttrsByFuncDefaultsClean [ { name = "${name}-${version}"; } base (maybeAttr version (throw "bad version ${version} for ${name}") attrsByVersion)];
# sane defaults (same name as attr name so that inherit can be used)
mergeAttrBy = # { buildInputs = concatList; [...]; passthru = mergeAttr; [..]; }
listToAttrs (map (n : nameValuePair n lib.concat) [ "nativeBuildInputs" "buildInputs" "propagatedBuildInputs" "configureFlags" "prePhases" "postAll" ])
// listToAttrs (map (n : nameValuePair n lib.mergeAttrs) [ "passthru" "meta" "cfg" "flags" ])
// listToAttrs (map (n : nameValuePair n (a: b: "${a}\n${b}") ) [ "preConfigure" "postInstall" ])
;
# prepareDerivationArgs tries to make writing configurable derivations easier
# example:
# prepareDerivationArgs {
# mergeAttrBy = {
# myScript = x : y : x ++ "\n" ++ y;
# };
# cfg = {
# readlineSupport = true;
# };
# flags = {
# readline = {
# set = {
# configureFlags = [ "--with-compiler=${compiler}" ];
# buildInputs = [ compiler ];
# pass = { inherit compiler; READLINE=1; };
# assertion = compiler.dllSupport;
# myScript = "foo";
# };
# unset = { configureFlags = ["--without-compiler"]; };
# };
# };
# src = ...
# buildPhase = '' ... '';
# name = ...
# myScript = "bar";
# };
# if you don't have need for unset you can omit the surrounding set = { .. } attr
# all attrs except flags cfg and mergeAttrBy will be merged with the
# additional data from flags depending on config settings
# It's used in composableDerivation in all-packages.nix. It's also used
# heavily in the new python and libs implementation
#
# should we check for misspelled cfg options?
# TODO use args.mergeFun here as well?
prepareDerivationArgs = args:
let args2 = { cfg = {}; flags = {}; } // args;
flagName = name : "${name}Support";
cfgWithDefaults = (listToAttrs (map (n : nameValuePair (flagName n) false) (attrNames args2.flags)))
// args2.cfg;
opts = attrValues (mapAttrs (a : v :
let v2 = if v ? set || v ? unset then v else { set = v; };
n = if (getAttr (flagName a) cfgWithDefaults) then "set" else "unset";
attr = maybeAttr n {} v2; in
if (maybeAttr "assertion" true attr)
then attr
else throw "assertion of flag ${a} of derivation ${args.name} failed"
) args2.flags );
in removeAttrs
(mergeAttrsByFuncDefaults ([args] ++ opts ++ [{ passthru = cfgWithDefaults; }]))
["flags" "cfg" "mergeAttrBy" ];
nixType = x:
if isAttrs x then
if x ? outPath then "derivation"
else "aattrs"
else if isFunction x then "function"
else if isList x then "list"
else if x == true then "bool"
else if x == false then "bool"
else if x == null then "null"
else if isInt x then "int"
else "string";
}
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