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# Tested in lib/tests/filesystem.shlet inherit (builtins) pathExists toString ;
inherit (lib.filesystem) pathIsDirectory pathType packagesFromDirectoryRecursive ;
inherit (lib.strings) hasSuffix ;in
{ inherit (builtins) baseNameOf dirOf isPath ;
inherit (builtins) readDir readFileType hashFile ;
/** The type of a path. The path needs to exist and be accessible. The result is either `"directory"` for a directory, `"regular"` for a regular file, `"symlink"` for a symlink, or `"unknown"` for anything else.
# Inputs
path
: The path to query
# Type
``` pathType :: Path -> String ```
# Examples :::{.example} ## `lib.filesystem.pathType` usage example
```nix pathType /. => "directory"
pathType /some/file.nix => "regular" ```
::: */ pathType = builtins.readFileType;
/** Whether a path exists and is a directory.
# Inputs
`path`
: 1\. Function argument
# Type
``` pathIsDirectory :: Path -> Bool ```
# Examples :::{.example} ## `lib.filesystem.pathIsDirectory` usage example
```nix pathIsDirectory /. => true
pathIsDirectory /this/does/not/exist => false
pathIsDirectory /some/file.nix => false ```
::: */ pathIsDirectory = path: pathExists path && pathType path == "directory";
/** Whether a path exists and is a regular file, meaning not a symlink or any other special file type.
# Inputs
`path`
: 1\. Function argument
# Type
``` pathIsRegularFile :: Path -> Bool ```
# Examples :::{.example} ## `lib.filesystem.pathIsRegularFile` usage example
```nix pathIsRegularFile /. => false
pathIsRegularFile /this/does/not/exist => false
pathIsRegularFile /some/file.nix => true ```
::: */ pathIsRegularFile = path: pathExists path && pathType path == "regular";
/** A map of all haskell packages defined in the given path, identified by having a cabal file with the same name as the directory itself.
# Inputs
`root`
: The directory within to search
# Type
``` haskellPathsInDir :: Path -> { [String] :: Path } ``` */ haskellPathsInDir = root: let # Files in the root root-files = builtins.attrNames (builtins.readDir root); # Files with their full paths root-files-with-paths = map (file: { name = file; value = root + "/${file}"; }) root-files; # Subdirectories of the root with a cabal file. cabal-subdirs = builtins.filter ( { name, value }: builtins.pathExists (value + "/${name}.cabal") ) root-files-with-paths; in builtins.listToAttrs cabal-subdirs; /** Find the first directory containing a file matching `pattern` upward from a given `file`. Returns `null` if no directories contain a file matching `pattern`.
# Inputs
`pattern`
: The pattern to search for
`file`
: The file to start searching upward from
# Type
``` locateDominatingFile :: RegExp -> Path -> ({ path :: Path; matches :: [MatchResults]; } | Null) ``` */ locateDominatingFile = pattern: file: let go = path: let files = builtins.attrNames (builtins.readDir path); matches = builtins.filter (match: match != null) (map (builtins.match pattern) files); in if builtins.length matches != 0 then { inherit path matches; } else if path == /. then null else go (dirOf path); parent = dirOf file; isDir = let base = baseNameOf file; type = (builtins.readDir parent).${base} or null; in file == /. || type == "directory"; in go (if isDir then file else parent);
/** Given a directory, return a flattened list of all files within it recursively.
# Inputs
`dir`
: The path to recursively list
# Type
``` listFilesRecursive :: Path -> [Path] ``` */ listFilesRecursive = let # We only flatten at the very end, as flatten is recursive. internalFunc = dir: (lib.mapAttrsToList ( name: type: if type == "directory" then internalFunc (dir + "/${name}") else dir + "/${name}" ) (builtins.readDir dir)); in dir: lib.flatten (internalFunc dir);
/** Transform a directory tree containing package files suitable for `callPackage` into a matching nested attribute set of derivations.
For a directory tree like this:
``` my-packages ├── a.nix ├── b.nix ├── c │ ├── my-extra-feature.patch │ ├── package.nix │ └── support-definitions.nix └── my-namespace ├── d.nix ├── e.nix └── f └── package.nix ```
`packagesFromDirectoryRecursive` will produce an attribute set like this:
```nix # packagesFromDirectoryRecursive { # callPackage = pkgs.callPackage; # directory = ./my-packages; # } { a = pkgs.callPackage ./my-packages/a.nix { }; b = pkgs.callPackage ./my-packages/b.nix { }; c = pkgs.callPackage ./my-packages/c/package.nix { }; my-namespace = { d = pkgs.callPackage ./my-packages/my-namespace/d.nix { }; e = pkgs.callPackage ./my-packages/my-namespace/e.nix { }; f = pkgs.callPackage ./my-packages/my-namespace/f/package.nix { }; }; } ```
In particular: - If the input directory contains a `package.nix` file, then `callPackage <directory>/package.nix { }` is returned. - Otherwise, the input directory's contents are listed and transformed into an attribute set. - If a regular file's name has the `.nix` extension, it is turned into attribute where: - The attribute name is the file name without the `.nix` extension - The attribute value is `callPackage <file path> { }` - Directories are turned into an attribute where: - The attribute name is the name of the directory - The attribute value is the result of calling `packagesFromDirectoryRecursive { ... }` on the directory.
As a result, directories with no `.nix` files (including empty directories) will be transformed into empty attribute sets. - Other files are ignored, including symbolic links to directories and to regular `.nix` files; this is because nixlang code cannot distinguish the type of a link's target.
# Inputs
`callPackage` : The function used to convert a Nix file's path into a leaf of the attribute set. It is typically the `callPackage` function, taken from either `pkgs` or a new scope corresponding to the `directory`.
`newScope` : If present, this function is used when recursing into a directory, to generate a new scope. The arguments are updated with the scope's `callPackage` and `newScope` functions, so packages can require anything in their scope, or in an ancestor of their scope.
`directory` : The directory to read package files from.
# Type
``` packagesFromDirectoryRecursive :: { callPackage :: Path -> AttrSet -> Any; newScope? :: AttrSet -> Scope; directory :: Path; } -> AttrSet ```
# Examples :::{.example} ## Basic use of `lib.packagesFromDirectoryRecursive`
```nix packagesFromDirectoryRecursive { inherit (pkgs) callPackage; directory = ./my-packages; } => { ... } ```
In this case, `callPackage` will only search `pkgs` for a file's input parameters. In other words, a file cannot refer to another file in the directory in its input parameters. :::
::::{.example} ## Create a scope for the nix files found in a directory ```nix packagesFromDirectoryRecursive { inherit (pkgs) callPackage newScope; directory = ./my-packages; } => { ... } ```
For example, take the following directory structure: ``` my-packages ├── a.nix → { b }: assert b ? b1; ... └── b ├── b1.nix → { a }: ... └── b2.nix ```
Here, `b1.nix` can specify `{ a }` as a parameter, which `callPackage` will resolve as expected. Likewise, `a.nix` receive an attrset corresponding to the contents of the `b` directory.
:::{.note} `a.nix` cannot directly take as inputs packages defined in a child directory, such as `b1`. ::: :::: */ packagesFromDirectoryRecursive = let inherit (lib) concatMapAttrs id makeScope recurseIntoAttrs removeSuffix ;
# Generate an attrset corresponding to a given directory. # This function is outside `packagesFromDirectoryRecursive`'s lambda expression, # to prevent accidentally using its parameters. processDir = { callPackage, directory, ... }@args: concatMapAttrs ( name: type: # for each directory entry let path = directory + "/${name}"; in if type == "directory" then { # recurse into directories "${name}" = packagesFromDirectoryRecursive ( args // { directory = path; } ); } else if type == "regular" && hasSuffix ".nix" name then { # call .nix files "${removeSuffix ".nix" name}" = callPackage path { }; } else if type == "regular" then { # ignore non-nix files } else throw '' lib.filesystem.packagesFromDirectoryRecursive: Unsupported file type ${type} at path ${toString path} '' ) (builtins.readDir directory); in { callPackage, newScope ? throw "lib.packagesFromDirectoryRecursive: newScope wasn't passed in args", directory, }@args: let defaultPath = directory + "/package.nix"; in if pathExists defaultPath then # if `${directory}/package.nix` exists, call it directly callPackage defaultPath { } else if args ? newScope then # Create a new scope and mark it `recurseForDerivations`. # This lets the packages refer to each other. # See: # [lib.makeScope](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.customisation.makeScope) and # [lib.recurseIntoAttrs](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.customisation.makeScope) recurseIntoAttrs ( makeScope newScope ( self: # generate the attrset representing the directory, using the new scope's `callPackage` and `newScope` processDir ( args // { inherit (self) callPackage newScope; } ) ) ) else processDir args;
/** Append `/default.nix` if the passed path is a directory.
# Inputs
A single argument which can be a [path](https://nix.dev/manual/nix/stable/language/types#type-path) value or a string containing an absolute path.
# Output
If the input refers to a directory that exists, the output is that same path with `/default.nix` appended. Furthermore, if the input is a string that ends with `/`, `default.nix` is appended to it. Otherwise, the input is returned unchanged.
# Type
``` resolveDefaultNix :: (Path | String) -> (Path | String) ```
# Examples :::{.example} ## `lib.filesystem.resolveDefaultNix` usage example
This expression checks whether `a` and `b` refer to the same locally available Nix file path.
```nix resolveDefaultNix a == resolveDefaultNix b ```
For instance, if `a` is `/some/dir` and `b` is `/some/dir/default.nix`, and `/some/dir/` exists, the expression evaluates to `true`, despite `a` and `b` being different references to the same Nix file. */ resolveDefaultNix = v: if pathIsDirectory v then v + "/default.nix" else if lib.isString v && hasSuffix "/" v then # A path ending in `/` can only refer to a directory, so we take the hint, even if we can't verify the validity of the path's `/` assertion. # A `/` is already present, so we don't add another one. v + "default.nix" else v;}