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Diffstat (limited to 'pkgs/lib/properties.nix')
| -rw-r--r-- | pkgs/lib/properties.nix | 464 |
1 files changed, 0 insertions, 464 deletions
diff --git a/pkgs/lib/properties.nix b/pkgs/lib/properties.nix deleted file mode 100644 index 22aa8d891d8a..000000000000 --- a/pkgs/lib/properties.nix +++ /dev/null @@ -1,464 +0,0 @@ -# Nixpkgs/NixOS properties. Generalize the problem of delayable (not yet -# evaluable) properties like mkIf. - -let lib = import ./default.nix; in - -with { inherit (builtins) head tail; }; -with import ./trivial.nix; -with import ./lists.nix; -with import ./misc.nix; -with import ./attrsets.nix; - -rec { - - inherit (lib) isType; - - # Tell that nothing is defined. When properties are evaluated, this type - # is used to remove an entry. Thus if your property evaluation semantic - # implies that you have to mute the content of an attribute, then your - # property should produce this value. - isNotdef = isType "notdef"; - mkNotdef = {_type = "notdef";}; - - # General property type, it has a property attribute and a content - # attribute. The property attribute refers to an attribute set which - # contains a _type attribute and a list of functions which are used to - # evaluate this property. The content attribute is used to stack properties - # on top of each other. - # - # The optional functions which may be contained in the property attribute - # are: - # - onDelay: run on a copied property. - # - onGlobalDelay: run on all copied properties. - # - onEval: run on an evaluated property. - # - onGlobalEval: run on a list of property stack on top of their values. - isProperty = isType "property"; - mkProperty = p@{property, content, ...}: p // { - _type = "property"; - }; - - # Go through the stack of properties and apply the function `op' on all - # property and call the function `nul' on the final value which is not a - # property. The stack is traversed in reversed order. The `op' function - # should expect a property with a content which have been modified. - # - # Warning: The `op' function expects only one argument in order to avoid - # calls to mkProperties as the argument is already a valid property which - # contains the result of the folding inside the content attribute. - foldProperty = op: nul: attrs: - if isProperty attrs then - op (attrs // { - content = foldProperty op nul attrs.content; - }) - else - nul attrs; - - # Simple function which can be used as the `op' argument of the - # foldProperty function. Properties that you don't want to handle can be - # ignored with the `id' function. `isSearched' is a function which should - # check the type of a property and return a boolean value. `thenFun' and - # `elseFun' are functions which behave as the `op' argument of the - # foldProperty function. - foldFilter = isSearched: thenFun: elseFun: attrs: - if isSearched attrs.property then - thenFun attrs - else - elseFun attrs; - - - # Move properties from the current attribute set to the attribute - # contained in this attribute set. This trigger property handlers called - # `onDelay' and `onGlobalDelay'. - delayPropertiesWithIter = iter: path: attrs: - let cleanAttrs = rmProperties attrs; in - if isProperty attrs then - iter (a: v: - lib.addErrorContext "while moving properties on the attribute `${a}':" ( - triggerPropertiesGlobalDelay a ( - triggerPropertiesDelay a ( - copyProperties attrs v - )))) path cleanAttrs - else - attrs; - - delayProperties = # implicit attrs argument. - let - # mapAttrs except that it also recurse into potential mkMerge - # functions. This may cause a strictness issue because looking the - # type of a string implies evaluating it. - iter = fun: path: value: - lib.mapAttrs (attr: val: - if isProperty val && isMerge val.property then - val // { content = map (fun attr) val.content; } - else - fun attr val - ) value; - in - delayPropertiesWithIter iter ""; - - # Call onDelay functions. - triggerPropertiesDelay = name: attrs: - let - callOnDelay = p@{property, ...}: - if property ? onDelay then - property.onDelay name p - else - p; - in - foldProperty callOnDelay id attrs; - - # Call onGlobalDelay functions. - triggerPropertiesGlobalDelay = name: attrs: - let - globalDelayFuns = uniqListExt { - getter = property: property._type; - inputList = foldProperty (p@{property, content, ...}: - if property ? onGlobalDelay then - [ property ] ++ content - else - content - ) (a: []) attrs; - }; - - callOnGlobalDelay = property: content: - property.onGlobalDelay name content; - in - fold callOnGlobalDelay attrs globalDelayFuns; - - # Expect a list of values which may have properties and return the same - # list of values where all properties have been evaluated and where all - # ignored values are removed. This trigger property handlers called - # `onEval' and `onGlobalEval'. - evalProperties = valList: - if valList != [] then - filter (x: !isNotdef x) ( - triggerPropertiesGlobalEval ( - evalLocalProperties valList - ) - ) - else - valList; - - evalLocalProperties = valList: - filter (x: !isNotdef x) ( - map triggerPropertiesEval valList - ); - - # Call onEval function - triggerPropertiesEval = val: - foldProperty (p@{property, ...}: - if property ? onEval then - property.onEval p - else - p - ) id val; - - # Call onGlobalEval function - triggerPropertiesGlobalEval = valList: - let - globalEvalFuns = uniqListExt { - getter = property: property._type; - inputList = - fold (attrs: list: - foldProperty (p@{property, content, ...}: - if property ? onGlobalEval then - [ property ] ++ content - else - content - ) (a: list) attrs - ) [] valList; - }; - - callOnGlobalEval = property: valList: property.onGlobalEval valList; - in - fold callOnGlobalEval valList globalEvalFuns; - - # Remove all properties on top of a value and return the value. - rmProperties = - foldProperty (p@{content, ...}: content) id; - - # Copy properties defined on a value on another value. - copyProperties = attrs: newAttrs: - foldProperty id (x: newAttrs) attrs; - - /* Merge. */ - - # Create "merge" statement which is skipped by the delayProperty function - # and interpreted by the underlying system using properties (modules). - - # Create a "Merge" property which only contains a condition. - isMerge = isType "merge"; - mkMerge = content: mkProperty { - property = { - _type = "merge"; - onDelay = name: val: throw "mkMerge is not the first of the list of properties."; - onEval = val: throw "mkMerge is not allowed on option definitions."; - }; - inherit content; - }; - - /* If. ThenElse. Always. */ - - # create "if" statement that can be delayed on sets until a "then-else" or - # "always" set is reached. When an always set is reached the condition - # is ignore. - - # Create a "If" property which only contains a condition. - isIf = isType "if"; - mkIf = condition: content: mkProperty { - property = { - _type = "if"; - onGlobalDelay = onIfGlobalDelay; - onEval = onIfEval; - inherit condition; - }; - inherit content; - }; - - mkAssert = assertion: message: content: - mkIf - (if assertion then true else throw "\nFailed assertion: ${message}") - content; - - # Evaluate the "If" statements when either "ThenElse" or "Always" - # statement is encountered. Otherwise it removes multiple If statements and - # replaces them by one "If" statement where the condition is the list of all - # conditions joined with a "and" operation. - onIfGlobalDelay = name: content: - let - # extract if statements and non-if statements and repectively put them - # in the attribute list and attrs. - ifProps = - foldProperty - (foldFilter (p: isIf p) - # then, push the condition inside the list list - (p@{property, content, ...}: - { inherit (content) attrs; - list = [property] ++ content.list; - } - ) - # otherwise, add the propertie. - (p@{property, content, ...}: - { inherit (content) list; - attrs = p // { content = content.attrs; }; - } - ) - ) - (attrs: { list = []; inherit attrs; }) - content; - - # compute the list of if statements. - evalIf = content: condition: list: - if list == [] then - mkIf condition content - else - let p = head list; in - evalIf content (condition && p.condition) (tail list); - in - evalIf ifProps.attrs true ifProps.list; - - # Evaluate the condition of the "If" statement to either get the value or - # to ignore the value. - onIfEval = p@{property, content, ...}: - if property.condition then - content - else - mkNotdef; - - /* mkOverride */ - - # Create an "Override" statement which allow the user to define - # priorities between values. The default priority is 100. The lowest - # priorities are kept. The template argument must reproduce the same - # attribute set hierarchy to override leaves of the hierarchy. - isOverride = isType "override"; - mkOverrideTemplate = priority: template: content: mkProperty { - property = { - _type = "override"; - onDelay = onOverrideDelay; - onGlobalEval = onOverrideGlobalEval; - inherit priority template; - }; - inherit content; - }; - - # Like mkOverrideTemplate, but without the template argument. - mkOverride = priority: content: mkOverrideTemplate priority {} content; - - # Sugar to override the default value of the option by making a new - # default value based on the configuration. - mkDefaultValue = mkOverride 1000; - mkDefault = mkOverride 1000; - mkForce = mkOverride 50; - mkStrict = mkOverride 0; - - # Make the template traversal in function of the property traversal. If - # the template define a non-empty attribute set, then the property is - # copied only on all mentionned attributes inside the template. - # Otherwise, the property is kept on all sub-attribute definitions. - onOverrideDelay = name: p@{property, content, ...}: - let inherit (property) template; in - if isAttrs template && template != {} then - if hasAttr name template then - p // { - property = p.property // { - template = builtins.getAttr name template; - }; - } - # Do not override the attribute \name\ - else - content - # Override values defined inside the attribute \name\. - else - p; - - # Keep values having lowest priority numbers only throwing away those having - # a higher priority assigned. - onOverrideGlobalEval = valList: - let - defaultPrio = 100; - - inherit (builtins) lessThan; - - getPrioVal = - foldProperty - (foldFilter isOverride - (p@{property, content, ...}: - if content ? priority && lessThan content.priority property.priority then - content - else - content // { - inherit (property) priority; - } - ) - (p@{property, content, ...}: - content // { - value = p // { content = content.value; }; - } - ) - ) (value: { inherit value; }); - - addDefaultPrio = x: - if x ? priority then x - else x // { priority = defaultPrio; }; - - prioValList = map (x: addDefaultPrio (getPrioVal x)) valList; - - higherPrio = - if prioValList == [] then - defaultPrio - else - fold (x: min: - if lessThan x.priority min then - x.priority - else - min - ) (head prioValList).priority (tail prioValList); - in - map (x: - if x.priority == higherPrio then - x.value - else - mkNotdef - ) prioValList; - - /* mkOrder */ - - # Order definitions based on there index value. This property is useful - # when the result of the merge function depends on the order on the - # initial list. (e.g. concatStrings) Definitions are ordered based on - # their rank. The lowest ranked definition would be the first to element - # of the list used by the merge function. And the highest ranked - # definition would be the last. Definitions which does not have any rank - # value have the default rank of 100. - isOrder = isType "order"; - mkOrder = rank: content: mkProperty { - property = { - _type = "order"; - onGlobalEval = onOrderGlobalEval; - inherit rank; - }; - inherit content; - }; - - mkHeader = mkOrder 10; - mkFooter = mkOrder 1000; - - # Fetch the rank of each definition (add the default rank is none) and - # sort them based on their ranking. - onOrderGlobalEval = valList: - let - defaultRank = 100; - - inherit (builtins) lessThan; - - getRankVal = - foldProperty - (foldFilter isOrder - (p@{property, content, ...}: - if content ? rank then - content - else - content // { - inherit (property) rank; - } - ) - (p@{property, content, ...}: - content // { - value = p // { content = content.value; }; - } - ) - ) (value: { inherit value; }); - - addDefaultRank = x: - if x ? rank then x - else x // { rank = defaultRank; }; - - rankValList = map (x: addDefaultRank (getRankVal x)) valList; - - cmp = x: y: - builtins.lessThan x.rank y.rank; - in - map (x: x.value) (sort cmp rankValList); - - /* mkFixStrictness */ - - # This is a hack used to restore laziness on some option definitions. - # Some option definitions are evaluated when they are not used. This - # error is caused by the strictness of type checking builtins. Builtins - # like 'isAttrs' are too strict because they have to evaluate their - # arguments to check if the type is correct. This evaluation, cause the - # strictness of properties. - # - # Properties can be stacked on top of each other. The stackability of - # properties on top of the option definition is nice for user manipulation - # but require to check if the content of the property is not another - # property. Such testing implies to verify if this is an attribute set - # and if it possess the type 'property'. (see isProperty & typeOf/isType) - # - # To avoid strict evaluation of option definitions, 'mkFixStrictness' is - # introduced. This property protects an option definition by replacing - # the base of the stack of properties by 'mkNotDef', when this property is - # evaluated it returns the original definition. - # - # This property is useful over any elements which depends on options which - # are raising errors when they get evaluated without the proper settings. - # - # Plain list and attribute set are lazy structures, which means that the - # container gets evaluated but not the content. Thus, using this property - # on top of plain list or attribute set is pointless. - # - # This is a Hack, you should avoid it! - - # This property has a long name because you should avoid it. - isFixStrictness = attrs: (typeOf attrs) == "fix-strictness"; - mkFixStrictness = value: - mkProperty { - property = { - _type = "fix-strictness"; - onEval = p: value; - }; - content = mkNotdef; - }; - -} |