feat(wpcarro/emacs): Package fs.el r/4362

According to SourceGraph, this is unused, but I'm checking it in for historical
purposes.

Change-Id: I24bcb1c71a9f6de527bb54057cf13d01493c45bf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6016
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>

3 files changed, 102 insertions, 0 deletions

diff --git a/users/wpcarro/emacs/pkgs/fs/default.nix b/users/wpcarro/emacs/pkgs/fs/default.nix
new file mode 100644
index 000000000000..e6afd107e96b
--- /dev/null
+++ b/users/wpcarro/emacs/pkgs/fs/default.nix
@@ -0,0 +1,29 @@
+{ pkgs, depot, ... }:
+
+let
+  fs = pkgs.callPackage
+    ({ emacsPackages }:
+      emacsPackages.trivialBuild {
+        pname = "fs";
+        version = "1.0.0";
+        src = ./fs.el;
+        packageRequires =
+          (with emacsPackages; [
+            dash
+            f
+            s
+          ]);
+      })
+    { };
+
+  emacs = (pkgs.emacsPackagesFor pkgs.emacs28).emacsWithPackages (epkgs: [
+    fs
+  ]);
+in
+fs.overrideAttrs (_old: {
+  doCheck = true;
+  checkPhase = ''
+    ${emacs}/bin/emacs -batch \
+      -l ert -l ${./tests.el} -f ert-run-tests-batch-and-exit
+  '';
+})
diff --git a/users/wpcarro/emacs/pkgs/fs/fs.el b/users/wpcarro/emacs/pkgs/fs/fs.el
new file mode 100644
index 000000000000..125c1f1007bd
--- /dev/null
+++ b/users/wpcarro/emacs/pkgs/fs/fs.el
@@ -0,0 +1,47 @@
+;;; fs.el --- Make working with the filesystem easier -*- lexical-binding: t -*-
+
+;; Author: William Carroll <wpcarro@gmail.com>
+;; Version: 0.0.1
+;; Package-Requires: ((emacs "24.1"))
+
+;;; Commentary:
+;; Ergonomic alternatives for working with the filesystem.
+
+;;; Code:
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'dash)
+(require 'f)
+(require 's)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Library
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(defun fs-ensure-file (path)
+  "Ensure that a file and its directories in `PATH' exist.
+Will error for inputs with a trailing slash."
+  (when (s-ends-with? "/" path)
+    (error (format "Input path has trailing slash: %s" path)))
+  (->> path
+       f-dirname
+       fs-ensure-dir)
+  (f-touch path))
+
+(defun fs-ensure-dir (path)
+  "Ensure that a directory and its ancestor directories in `PATH' exist."
+  (->> path
+       f-split
+       (apply #'f-mkdir)))
+
+(defun fs-ls (dir &optional full-path?)
+  "List the files in `DIR' one-level deep.
+Should behave similarly in spirit to the Unix command, ls.
+If `FULL-PATH?' is set, return the full-path of the files."
+  (-drop 2 (directory-files dir full-path?)))
+
+(provide 'fs)
+;;; fs.el ends here
diff --git a/users/wpcarro/emacs/pkgs/fs/tests.el b/users/wpcarro/emacs/pkgs/fs/tests.el
new file mode 100644
index 000000000000..adef11a607ae
--- /dev/null
+++ b/users/wpcarro/emacs/pkgs/fs/tests.el
@@ -0,0 +1,26 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'ert)
+(require 'fs)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Tests
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(ert-deftest fs-test-ensure-file ()
+  (let ((file "/tmp/file/a/b/c/file.txt"))
+    ;; Ensure this file doesn't exist first to prevent false-positives.
+    (f-delete file t)
+    (fs-ensure-file file)
+    (should (and (f-exists? file)
+                 (f-file? file)))))
+
+(ert-deftest fs-test-ensure-dir ()
+  (let ((dir "/tmp/dir/a/b/c"))
+    ;; Ensure the directory doesn't exist.
+    (f-delete dir t)
+    (fs-ensure-dir dir)
+    (should (and (f-exists? dir)
+                 (f-dir? dir)))))