60 lines
2.0 KiB
Nix
60 lines
2.0 KiB
Nix
{ lib }:
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# This Nix expression allows filtering a local directory by
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# specifying dirRootsToInclude, dirsToExclude and filesToInclude.
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# It also filters out symlinks to result folders created by nix-build,
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# as well as backup/swap/generated files.
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let
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inherit (lib)
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any range flatten length sublist cleanSourceFilter
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splitString hasPrefix removePrefix concatStringsSep;
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inherit (builtins) map match;
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mkFilter = {
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# primary path under which all files are included, unless excluded
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root,
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# list of regex expressions to match files to include/exclude
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include ? [ ], exclude ? [ ], # has precedence over include
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}:
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let
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# removes superfluous slashes from the path
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cleanRoot = "${toString (/. + root)}/";
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in path: type:
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let
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# unpack path: "x/y/.*" => ["x" "x/y" "x/y/.*"]
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unpackPath = path:
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let
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tokens = splitString "/" path;
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perms = range 1 (length tokens);
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subPaths = builtins.map (x: sublist 0 x tokens) perms;
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in builtins.map (x: concatStringsSep "/" x) subPaths;
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# accept subdirs from regexes
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includeSubdirs = regexes: flatten (map unpackPath regexes);
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# checks all regexes in a list against str
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matchesRegexes = str: regexes: (map (r: (match r str)) regexes);
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# match returns empty list on match
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isMatch = x: x == [ ];
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# path relative to search root
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relPath = removePrefix cleanRoot path;
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# check if any of the regexes match the relative path
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checkRegexes = regexes: any isMatch (matchesRegexes relPath regexes);
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# main check methods
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isRootSubdir = hasPrefix cleanRoot path;
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isIncluded = checkRegexes (includeSubdirs include);
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isExcluded = checkRegexes exclude;
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isSCV = !cleanSourceFilter path type;
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in
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if !isRootSubdir then
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# everything outside of root is excluded
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false
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else if isExcluded || isSCV then
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# isExcluded has precedence over isIncluded
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false
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else
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isIncluded;
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in mkFilter
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