lib.fileset.fileFilter: init (f4e00430) · Commits · nix / nixpkgs

lib/fileset/default.nix

+51 −0

Original line number	Diff line number	Diff line
		@@ -6,6 +6,7 @@ let
		_coerceMany
		_toSourceFilter
		_unionMany
		_fileFilter
		_printFileset
		_intersection
		;
		@@ -41,6 +42,7 @@ let
		;

		inherit (lib.trivial)
		isFunction
		pipe
		;

		@@ -278,6 +280,55 @@ If a directory does not recursively contain any file, it is omitted from the sto
		_unionMany
		];

		/*
		Filter a file set to only contain files matching some predicate.

		Type:
		fileFilter ::
		({
		name :: String,
		type :: String,
		...
		} -> Bool)
		-> FileSet
		-> FileSet

		Example:
		# Include all regular `default.nix` files in the current directory
		fileFilter (file: file.name == "default.nix") ./.

		# Include all non-Nix files from the current directory
		fileFilter (file: ! hasSuffix ".nix" file.name) ./.

		# Include all files that start with a "." in the current directory
		fileFilter (file: hasPrefix "." file.name) ./.

		# Include all regular files (not symlinks or others) in the current directory
		fileFilter (file: file.type == "regular")
		*/
		fileFilter =
		/*
		The predicate function to call on all files contained in given file set.
		A file is included in the resulting file set if this function returns true for it.

		This function is called with an attribute set containing these attributes:

		- `name` (String): The name of the file

		- `type` (String, one of `"regular"`, `"symlink"` or `"unknown"`): The type of the file.
		This matches result of calling [`builtins.readFileType`](https://nixos.org/manual/nix/stable/language/builtins.html#builtins-readFileType) on the file's path.

		Other attributes may be added in the future.
		*/
		predicate:
		# The file set to filter based on the predicate function
		fileset:
		if ! isFunction predicate then
		throw "lib.fileset.fileFilter: Expected the first argument to be a function, but it's a ${typeOf predicate} instead."
		else
		_fileFilter predicate
		(_coerce "lib.fileset.fileFilter: second argument" fileset);

		/*
		The file set containing all files that are in both of two given file sets.
		See also [Intersection (set theory)](https://en.wikipedia.org/wiki/Intersection_(set_theory)).

lib/fileset/internal.nix

+26 −0

Original line number	Diff line number	Diff line
		@@ -638,4 +638,30 @@ rec {
		else
		# In all other cases it's the rhs
		rhs;

		_fileFilter = predicate: fileset:
		let
		recurse = path: tree:
		mapAttrs (name: subtree:
		if isAttrs subtree \|\| subtree == "directory" then
		recurse (path + "/${name}") subtree
		else if
		predicate {
		inherit name;
		type = subtree;
		# To ensure forwards compatibility with more arguments being added in the future,
		# adding an attribute which can't be deconstructed :)
		"lib.fileset.fileFilter: The predicate function passed as the first argument must be able to handle extra attributes for future compatibility. If you're using `{ name, file }:`, use `{ name, file, ... }:` instead." = null;
		}
		then
		subtree
		else
		null
		) (_directoryEntries path tree);
		in
		if fileset._internalIsEmptyWithoutBase then
		_emptyWithoutBase
		else
		_create fileset._internalBase
		(recurse fileset._internalBase fileset._internalTree);
		}

lib/fileset/tests.sh

+67 −0

Original line number	Diff line number	Diff line
		@@ -678,6 +678,73 @@ tree=(
		checkFileset 'intersection (unions [ ./a/b ./c/d ./c/e ]) (unions [ ./a ./c/d/f ./c/e ])'


		## File filter

		# The predicate is not called when there's no files
		tree=()
		checkFileset 'fileFilter (file: abort "this is not needed") ./.'
		checkFileset 'fileFilter (file: abort "this is not needed") _emptyWithoutBase'

		# The predicate must be able to handle extra attributes
		touch a
		expectFailure 'toSource { root = ./.; fileset = fileFilter ({ name, type }: true) ./.; }' 'called with unexpected argument '\''"lib.fileset.fileFilter: The predicate function passed as the first argument must be able to handle extra attributes for future compatibility. If you'\''re using `\{ name, file \}:`, use `\{ name, file, ... \}:` instead."'\'
		rm -rf -- *

		# .name is the name, and it works correctly, even recursively
		tree=(
		[a]=1
		[b]=0
		[c/a]=1
		[c/b]=0
		[d/c/a]=1
		[d/c/b]=0
		)
		checkFileset 'fileFilter (file: file.name == "a") ./.'
		tree=(
		[a]=0
		[b]=1
		[c/a]=0
		[c/b]=1
		[d/c/a]=0
		[d/c/b]=1
		)
		checkFileset 'fileFilter (file: file.name != "a") ./.'

		# `.type` is the file type
		mkdir d
		touch d/a
		ln -s d/b d/b
		mkfifo d/c
		expectEqual \
		'toSource { root = ./.; fileset = fileFilter (file: file.type == "regular") ./.; }' \
		'toSource { root = ./.; fileset = ./d/a; }'
		expectEqual \
		'toSource { root = ./.; fileset = fileFilter (file: file.type == "symlink") ./.; }' \
		'toSource { root = ./.; fileset = ./d/b; }'
		expectEqual \
		'toSource { root = ./.; fileset = fileFilter (file: file.type == "unknown") ./.; }' \
		'toSource { root = ./.; fileset = ./d/c; }'
		expectEqual \
		'toSource { root = ./.; fileset = fileFilter (file: file.type != "regular") ./.; }' \
		'toSource { root = ./.; fileset = union ./d/b ./d/c; }'
		expectEqual \
		'toSource { root = ./.; fileset = fileFilter (file: file.type != "symlink") ./.; }' \
		'toSource { root = ./.; fileset = union ./d/a ./d/c; }'
		expectEqual \
		'toSource { root = ./.; fileset = fileFilter (file: file.type != "unknown") ./.; }' \
		'toSource { root = ./.; fileset = union ./d/a ./d/b; }'
		rm -rf -- *

		# It's lazy
		tree=(
		[b]=1
		[c/a]=1
		)
		# Note that union evaluates the first argument first if necessary, that's why we can use ./c/a here
		checkFileset 'union ./c/a (fileFilter (file: assert file.name != "a"; true) ./.)'
		# but here we need to use ./c
		checkFileset 'union (fileFilter (file: assert file.name != "a"; true) ./.) ./c'

		## Tracing

		# The second trace argument is returned

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