add file_info function

Author: bcpeinhardt

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+## v1.5.0 - 29 February 2024
+- add `file_info` function.
+
 ## v1.4.2 - 18 February 2024
 - Update msg in deprecated tag for `is_directory` to correctly point to `verify_is_directory`
 

gleam.toml

@@ -1,5 +1,5 @@
 name = "simplifile"
-version = "1.4.2"
+version = "1.5.0"
 description = "Basic file operations that work on all targets"
 
 licences = ["Apache-2.0"]

src/simplifile.gleam

@@ -114,6 +114,55 @@ pub type FileError {
   Unknown
 }
 
+/// Represents the intersection of information available
+/// from erlang's `file:read_file_info` and node's `fs.stat`
+pub type FileInfo {
+  FileInfo(
+    /// File size in bytes.
+    size: Int,
+    /// File mode that indicates the file type and its permissions. 
+    /// For example, in Unix and Linux, a mode value of 33188 indicates 
+    /// a regular file and the permissions associated with it 
+    /// (read and write for the owner, and read-only for others, in 
+    /// this case).
+    mode: Int,
+    /// Number of hard links that exist for the file.
+    nlinks: Int,
+    /// Inode number, which is a unique identifier for the file in the filesystem.
+    inode: Int,
+    /// User ID of the file's owner.
+    user_id: Int,
+    /// Group ID of the file's group.
+    group_id: Int,
+    /// Device ID of the file's major device.
+    /// TODO: We can actually get a major device and minor device from both
+    /// node and erlang. The `fs.stat` in node returns a `dev` and `rdev`,
+    /// so we can use some bitwise operations to get the minor out of `rdev`.
+    /// Someone who's not me should totally make a PR for that.
+    dev: Int,
+    /// The last access time in seconds since the UNIX epoch (00:00:00 UTC on 1 January 1970).
+    atime_seconds: Int,
+    /// The last modification time in seconds since the UNIX epoch (00:00:00 UTC on 1 January 1970).
+    mtime_seconds: Int,
+    /// The last change time in seconds since the UNIX epoch (00:00:00 UTC on 1 January 1970).
+    ctime_seconds: Int,
+  )
+}
+
+@target(erlang)
+@external(erlang, "simplifile_erl", "file_info")
+fn do_file_info(a: String) -> Result(FileInfo, FileError)
+
+@target(javascript)
+@external(javascript, "./simplifile_js.mjs", "fileInfo")
+fn do_file_info(a: String) -> Result(FileInfo, String)
+
+/// Get information about a file at a given path
+pub fn file_info(a: String) -> Result(FileInfo, FileError) {
+  do_file_info(a)
+  |> cast_error
+}
+
 /// Read a files contents as a string
 /// ## Example
 /// ```gleam

src/simplifile_erl.erl

@@ -7,7 +7,9 @@
 -module(simplifile_erl).
 
 %% API
-- export ( [ read_file / 1 , append_file / 2 , write_file / 2 , delete_file / 1 , delete_directory / 1 , recursive_delete / 1 , list_directory / 1 , make_directory / 1 , is_file / 1 , create_dir_all / 1 , rename_file / 2 , set_permissions / 2 , is_valid_directory / 1 , is_valid_file/1 ] ) .
+-export([read_file/1, append_file/2, write_file/2, delete_file/1, delete_directory/1,
+         recursive_delete/1, list_directory/1, make_directory/1, is_file/1, create_dir_all/1,
+         rename_file/2, set_permissions/2, is_valid_directory/1, is_valid_file/1, file_info/1]).
 
 -include_lib("kernel/include/file.hrl").
 
@@ -155,3 +157,40 @@ is_valid_file(Path) ->
         {error, Reason} ->
             posix_result({error, Reason})
     end.
+
+file_info_result(Result) ->
+    case Result of
+        {ok,
+         {file_info,
+          Size,
+          _Type,
+          _Access,
+          Atime,
+          Mtime,
+          Ctime,
+          Mode,
+          Links,
+          MajorDevice,
+          _MinorDevice,
+          Inode,
+          Uid,
+          Gid}} ->
+            {ok,
+             {file_info,
+              Size,
+              Mode,
+              Links,
+              Inode,
+              Uid,
+              Gid,
+              MajorDevice,
+              Atime,
+              Mtime,
+              Ctime}};
+        {error, Reason} when ?is_posix_error(Reason) ->
+            Result
+    end.
+
+file_info(Filename) ->
+    file_info_result(file:read_file_info(Filename, [{time, posix}])).
+

src/simplifile_js.mjs

@@ -190,6 +190,31 @@ export function currentDirectory() {
     return gleamResult(() => process.cwd())
 }
 
+/**
+ * 
+ * @param {string} filepath 
+ * @returns {Ok | GError}
+ */
+export function fileInfo(filepath) {
+    return gleamResult(() => new FileInfo(filepath))
+}
+
+class FileInfo {
+    constructor(filepath) {
+        const stat = fs.statSync(path.normalize(filepath))
+        this.size = stat.size
+        this.mode = stat.mode
+        this.nlinks = stat.nlink
+        this.inode = stat.ino
+        this.userId = stat.uid
+        this.groupId = stat.gid
+        this.dev = stat.dev
+        this.atime = Math.floor(stat.atimeMs / 1000)
+        this.mtime = Math.floor(stat.mtimeMs / 1000)
+        this.ctime = Math.floor(stat.ctimeMs / 1000)
+    }
+}
+
 /**
  * Perform some operation and return a Gleam `Result(a, String)`
  * where `a` is the type returned by the operation and the `String`

test/simplifile_test.gleam

@@ -3,10 +3,10 @@ import gleeunit/should
 import simplifile.{
   Eacces, Enoent, Execute, FilePermissions, NotUtf8, Read, Write, append,
   append_bits, copy_directory, copy_file, create_directory, create_directory_all,
-  create_file, current_directory, delete, delete_all, file_permissions_to_octal,
-  get_files, read, read_bits, read_directory, rename_directory, rename_file,
-  set_permissions, set_permissions_octal, verify_is_directory, verify_is_file,
-  write, write_bits,
+  create_file, current_directory, delete, delete_all, file_info,
+  file_permissions_to_octal, get_files, read, read_bits, read_directory,
+  rename_directory, rename_file, set_permissions, set_permissions_octal,
+  verify_is_directory, verify_is_file, write, write_bits,
 }
 import gleam/list
 import gleam/int
@@ -383,22 +383,9 @@ pub fn no_read_permissions_test() {
   let assert Ok(Nil) = set_permissions_octal(parent_dir, 0o777)
   let assert Ok(Nil) = delete(parent_dir)
 }
-// pub fn is_file_and_is_dir_test() {
-//   let existing_file = "./gleam.toml"
-//   let existing_dir = "./test"
-//   let non_existing_file = "./i_dont_exist"
-//   let file_permission_issue = "/etc"
 
-//   let assert True = is_file(existing_file)
-//   let assert True = is_directory(existing_dir)
-
-//   let assert False = is_directory(existing_file)
-//   let assert False = is_file(existing_dir)
-
-//   let assert False = is_file(non_existing_file)
-//   let assert False = is_directory(non_existing_file)
-
-//   // let assert False = is_file(file_permission_issue)
-//   // This fails on javascript, because the permission error throws
-//   // let assert False = is_directory(file_permission_issue)
-// }
+pub fn file_info_test() {
+  let assert Ok(_info) = file_info("./test.sh")
+}
+/// I visually inspected this info to make sure it matched on all targets.
+/// TODO: Add a better test setup for validating file info functionality.