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Diffstat (limited to 'lib/fileset/default.nix')
| -rw-r--r-- | lib/fileset/default.nix | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/lib/fileset/default.nix b/lib/fileset/default.nix new file mode 100644 index 00000000000..b3012526552 --- /dev/null +++ b/lib/fileset/default.nix @@ -0,0 +1,131 @@ +{ lib }: +let + + inherit (import ./internal.nix { inherit lib; }) + _coerce + _toSourceFilter + ; + + inherit (builtins) + isPath + pathExists + typeOf + ; + + inherit (lib.path) + hasPrefix + splitRoot + ; + + inherit (lib.strings) + isStringLike + ; + + inherit (lib.filesystem) + pathType + ; + + inherit (lib.sources) + cleanSourceWith + ; + +in { + + /* + Add the local files contained in `fileset` to the store as a single [store path](https://nixos.org/manual/nix/stable/glossary#gloss-store-path) rooted at `root`. + + The result is the store path as a string-like value, making it usable e.g. as the `src` of a derivation, or in string interpolation: + ```nix + stdenv.mkDerivation { + src = lib.fileset.toSource { ... }; + # ... + } + ``` + + The name of the store path is always `source`. + + Type: + toSource :: { + root :: Path, + fileset :: FileSet, + } -> SourceLike + + Example: + # Import the current directory into the store but only include files under ./src + toSource { root = ./.; fileset = ./src; } + => "/nix/store/...-source" + + # The file set coerced from path ./bar could contain files outside the root ./foo, which is not allowed + toSource { root = ./foo; fileset = ./bar; } + => <error> + + # The root has to be a local filesystem path + toSource { root = "/nix/store/...-source"; fileset = ./.; } + => <error> + */ + toSource = { + /* + (required) The local directory [path](https://nixos.org/manual/nix/stable/language/values.html#type-path) that will correspond to the root of the resulting store path. + Paths in [strings](https://nixos.org/manual/nix/stable/language/values.html#type-string), including Nix store paths, cannot be passed as `root`. + `root` has to be a directory. + +<!-- Ignore the indentation here, this is a nixdoc rendering bug that needs to be fixed --> +:::{.note} +Changing `root` only affects the directory structure of the resulting store path, it does not change which files are added to the store. +The only way to change which files get added to the store is by changing the `fileset` attribute. +::: + */ + root, + /* + (required) The file set whose files to import into the store. + Currently the only way to construct file sets is using [implicit coercion from paths](#sec-fileset-path-coercion). + If a directory does not recursively contain any file, it is omitted from the store path contents. + */ + fileset, + }: + let + # We cannot rename matched attribute arguments, so let's work around it with an extra `let in` statement + # For now filesets are always paths + filesetPath = fileset; + in + let + fileset = _coerce "lib.fileset.toSource: `fileset`" filesetPath; + rootFilesystemRoot = (splitRoot root).root; + filesetFilesystemRoot = (splitRoot fileset._internalBase).root; + in + if ! isPath root then + if isStringLike root then + throw '' + lib.fileset.toSource: `root` "${toString root}" is a string-like value, but it should be a path instead. + Paths in strings are not supported by `lib.fileset`, use `lib.sources` or derivations instead.'' + else + throw '' + lib.fileset.toSource: `root` is of type ${typeOf root}, but it should be a path instead.'' + # Currently all Nix paths have the same filesystem root, but this could change in the future. + # See also ../path/README.md + else if rootFilesystemRoot != filesetFilesystemRoot then + throw '' + lib.fileset.toSource: Filesystem roots are not the same for `fileset` and `root` "${toString root}": + `root`: root "${toString rootFilesystemRoot}" + `fileset`: root "${toString filesetFilesystemRoot}" + Different roots are not supported.'' + else if ! pathExists root then + throw '' + lib.fileset.toSource: `root` ${toString root} does not exist.'' + else if pathType root != "directory" then + throw '' + lib.fileset.toSource: `root` ${toString root} is a file, but it should be a directory instead. Potential solutions: + - If you want to import the file into the store _without_ a containing directory, use string interpolation or `builtins.path` instead of this function. + - If you want to import the file into the store _with_ a containing directory, set `root` to the containing directory, such as ${toString (dirOf root)}, and set `fileset` to the file path.'' + else if ! hasPrefix root fileset._internalBase then + throw '' + lib.fileset.toSource: `fileset` could contain files in ${toString fileset._internalBase}, which is not under the `root` ${toString root}. Potential solutions: + - Set `root` to ${toString fileset._internalBase} or any directory higher up. This changes the layout of the resulting store path. + - Set `fileset` to a file set that cannot contain files outside the `root` ${toString root}. This could change the files included in the result.'' + else + cleanSourceWith { + name = "source"; + src = root; + filter = _toSourceFilter fileset; + }; +} |