stat: add more singleton accessor functions to File/Path

lib_eio/file.ml

@@ -27,35 +27,23 @@ module Stat = struct
     | `Socket -> Fmt.string ppf "socket"
 
   type 'a f =
-  | Dev : int64 f
-  | Ino : int64 f
-  | Kind : kind f
-  | Perm : int f
-  | Nlink : int64 f
-  | Uid : int64 f
-  | Gid : int64 f
-  | Rdev : int64 f
-  | Size : int64 f
-  | Atime : float f
-  | Ctime : float f
-  | Mtime : float f
+    | Dev : int64 f
+    | Ino : int64 f
+    | Kind : kind f
+    | Perm : int f
+    | Nlink : int64 f
+    | Uid : int64 f
+    | Gid : int64 f
+    | Rdev : int64 f
+    | Size : int64 f
+    | Atime : float f
+    | Ctime : float f
+    | Mtime : float f
 
   type ('a, 'ty) t =
     | [] : ('ty, 'ty) t
     | (::) : 'a f * ('b, 'ty) t -> ('a -> 'b, 'ty) t
 
-  let dev = Dev
-  let ino = Ino
-  let kind = Kind
-  let perm = Perm
-  let nlink = Nlink
-  let uid = Uid
-  let gid = Gid
-  let rdev = Rdev
-  let size = Size
-  let atime = Atime
-  let ctime = Ctime
-  let mtime = Mtime
 end
 
 type ro_ty = [`File | Flow.source_ty | Resource.close_ty]
@@ -105,8 +93,14 @@ let stat (Resource.T (t, ops)) =
   let module X = (val (Resource.get ops Pi.Read)) in
   X.stat t
 
-let size t =
-  stat t [Stat.size] (fun s -> Optint.Int63.of_int64 s)
+let kind t  = stat t [Stat.Kind] Fun.id
+let perm t  = stat t [Stat.Perm] Fun.id
+let uid t   = stat t [Stat.Uid] Fun.id
+let gid t   = stat t [Stat.Gid] Fun.id
+let size t  = stat t [Stat.Size] (fun s -> Optint.Int63.of_int64 s)
+let atime t = stat t [Stat.Atime] Fun.id
+let ctime t = stat t [Stat.Ctime] Fun.id
+let mtime t = stat t [Stat.Mtime] Fun.id
 
 let pread (Resource.T (t, ops)) ~file_offset bufs =
   let module X = (val (Resource.get ops Pi.Read)) in

lib_eio/file.mli

@@ -42,18 +42,6 @@ module Stat : sig
     | [] : ('ty, 'ty) t
     | (::) : 'a f * ('b, 'ty) t -> ('a -> 'b, 'ty) t
 
-  val dev   : int64 f
-  val ino   : int64 f
-  val kind  : kind f
-  val perm  : int f
-  val nlink : int64 f
-  val uid   : int64 f
-  val gid   : int64 f
-  val rdev  : int64 f
-  val size  : int64 f
-  val atime : float f
-  val ctime : float f
-  val mtime : float f
 end
 
 type ro_ty = [`File | Flow.source_ty | Resource.close_ty]
@@ -93,11 +81,59 @@ end
 
 val stat : _ ro -> ('a, 'b) Stat.t -> 'a -> 'b
 (** [stat t fields fn] will retrieve the file statistics for the specified
-    [fields] and apply them as arguments to [fn]. *)
+    [fields] and apply them as arguments to [fn].
+
+    For example, to print the kind of a file along with its size and last
+    modified time:
+
+    {[ File.stat t File.Stat.[ Kind; Size; Mtime ]
+        (fun kind size mtime ->
+          traceln "kind: %a size: %Ld mtime: %f"
+            File.Stat.pp_kind size mtime)
+     ]}
+   *)
+
+val kind : _ ro -> Stat.kind
+(** [kind t] returns the kind of file that [t] is.
+    Equivalent to [stat t [File.Kind] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
 
 val size : _ ro -> Optint.Int63.t
-(** [size t] returns the size of [t].
-    Equivalent to [stat t [File.size] Fun.id]. *)
+(** [size t] returns the size of [t]. Equivalent to [stat t [File.size] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val perm : _ ro -> int
+(** [perm t] returns the file permissions of [t].
+    Equivalent to [stat t [File.Perm] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val uid : _ ro -> int64
+(** [uid t] returns the user id associated with [t].
+    Equivalent to [stat t [File.Uid] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val gid : _ ro -> int64
+(** [gid t] returns the group id associated with [t].
+    Equivalent to [stat t [File.Gid] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val atime : _ ro -> float
+(** [atime t] returns the last access time of [t] as the seconds
+    since the start of the epoch.
+    Equivalent to [stat t [File.Atime] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val mtime : _ ro -> float
+(** [mtime t] returns the last modified time of [t] as the seconds
+    since the start of the epoch.
+    Equivalent to [stat t [File.Mtime] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val ctime : _ ro -> float
+(** [ctime t] returns the creation time of [t] as the seconds
+    since the start of the epoch.
+    Equivalent to [stat t [File.Ctime] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
 
 val pread : _ ro -> file_offset:Optint.Int63.t -> Cstruct.t list -> int
 (** [pread t ~file_offset bufs] performs a single read of [t] at [file_offset] into [bufs].

lib_eio/path.ml

@@ -69,6 +69,15 @@ let stat ~follow t =
     let bt = Printexc.get_raw_backtrace () in
     Exn.reraise_with_context ex bt "examining %a" pp t
 
+let kind  ~follow t = stat ~follow t [File.Stat.Kind] Fun.id
+let size  ~follow t = stat ~follow t [File.Stat.Size] Fun.id
+let perm  ~follow t = stat ~follow t [File.Stat.Perm] Fun.id
+let uid   ~follow t = stat ~follow t [File.Stat.Uid] Fun.id
+let gid   ~follow t = stat ~follow t [File.Stat.Gid] Fun.id
+let atime ~follow t = stat ~follow t [File.Stat.Atime] Fun.id
+let mtime ~follow t = stat ~follow t [File.Stat.Mtime] Fun.id
+let ctime ~follow t = stat ~follow t [File.Stat.Ctime] Fun.id
+
 let with_open_in path fn =
   Switch.run @@ fun sw -> fn (open_in ~sw path)
 

lib_eio/path.mli

@@ -134,7 +134,92 @@ val stat : follow:bool -> _ t -> ('a, 'b) File.Stat.t -> 'a -> 'b
 (** [stat ~follow t] returns metadata about the file [t].
 
     If [t] is a symlink, the information returned is about the target if [follow = true],
-    otherwise it is about the link itself. *)
+    otherwise it is about the link itself.
+
+    For example, to follow a symlink and print the kind, size and last modified
+    time of its target:
+
+    {[ Path.stat ~follow:true t File.Stat.[ Kind; Size; Mtime ]
+        (fun kind size mtime ->
+          traceln "kind: %a size: %Ld mtime: %f"
+            File.Stat.pp_kind size mtime)
+     ]}
+  *)
+
+val kind : follow:bool -> _ t -> File.Stat.kind
+(** [kind ~follow t] returns the kind of file that [t] is.
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Kind] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val size : follow:bool -> _ t -> int64
+(** [size ~follow t] returns the size of [t].
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.size] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val perm : follow:bool -> _ t -> int
+(** [perm ~follow t] returns the file permissions of [t].
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Perm] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val uid : follow:bool -> _ t -> int64
+(** [uid ~follow t] returns the user id associated with [t].
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Uid] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val gid : follow:bool -> _ t -> int64
+(** [gid ~follow t] returns the group id associated with [t].
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Gid] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val atime : follow:bool -> _ t -> float
+(** [atime ~follow t] returns the last access time of [t] as the seconds
+    since the start of the epoch.
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Atime] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val mtime : follow:bool -> _ t -> float
+(** [mtime ~follow t] returns the last modified time of [t] as the seconds
+    since the start of the epoch.
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Mtime] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
+
+val ctime : follow:bool -> _ t -> float
+(** [ctime t] returns the creation time of [t] as the seconds
+    since the start of the epoch.
+
+    If [t] is a symlink, the information returned is about the target if [follow = true],
+    otherwise it is about the link itself.
+
+    Equivalent to [stat ~follow t [File.Ctime] Fun.id],
+    so use {!stat} to query multiple items from a file in one call. *)
 
 (** {1 Other} *)
 

tests/fs.md

@@ -62,7 +62,7 @@ let chdir path =
 
 let assert_kind path kind =
   Path.with_open_in path @@ fun file ->
-  assert (Eio.File.(stat file [Stat.kind] ((=) kind)))
+  assert (Eio.File.kind file = kind)
 ```
 
 # Basic test cases
@@ -541,7 +541,7 @@ Fstatat:
   let cwd = Eio.Stdenv.cwd env in
   Switch.run @@ fun sw ->
   try_mkdir (cwd / "stat_subdir2");
-  Eio.Path.stat ~follow:true (cwd / "stat_subdir2") [Eio.File.Stat.kind] Fun.id
+  Eio.Path.kind ~follow:true (cwd / "stat_subdir2")
 +mkdir <cwd:stat_subdir2> -> ok
 - : Eio.File.Stat.kind = `Directory
 ```