Add the {encoding, _} options to file:open/2's modes

Although the {encoding, encoding()} set of options is documented in
the manual page of the 'file' module, they do not appear in the Mode
description on that page nor in the mode() type declaration.

The patch adds this information in both the code of the module and
the documentation of the module.

To avoid duplication, the declaration of the encoding() type is added
to the 'unicode' module where it most probably belongs.

While at it, added a proper declaration for posix(), took out the
now superfluous information about the types of file:open/2 from the
erl_bif_types module, and corrected the return type of file:open/2
so that it corresponds to the published documentation.

4 files changed, 30 insertions, 18 deletions

diff --git a/lib/hipe/cerl/erl_bif_types.erl b/lib/hipe/cerl/erl_bif_types.erl
index 835f9a205a..696414eb7a 100644
--- a/lib/hipe/cerl/erl_bif_types.erl
+++ b/lib/hipe/cerl/erl_bif_types.erl
@@ -2001,12 +2001,6 @@ type(file, get_cwd, 0, _) ->
 	t_tuple([t_atom('error'), t_file_posix_error()]));
 type(file, make_dir, 1, Xs) ->
   strict(arg_types(file, make_dir, 1), Xs, fun (_) -> t_file_return() end);
-type(file, open, 2, Xs) ->
-  strict(arg_types(file, open, 2), Xs,
-	 fun (_) ->
-	     t_sup([t_tuple([t_atom('ok'), t_file_io_device()]),
-		    t_tuple([t_atom('error'), t_file_posix_error()])])
-	 end);
 type(file, read_file, 1, Xs) ->
   strict(arg_types(file, read_file, 1), Xs,
 	 fun (_) ->
@@ -4214,8 +4208,6 @@ arg_types(file, get_cwd, 0) ->
   [];
 arg_types(file, make_dir, 1) ->
   [t_file_name()];
-arg_types(file, open, 2) ->
-  [t_file_name(), t_list(t_file_open_option())];
 arg_types(file, read_file, 1) ->
   [t_file_name()];
 arg_types(file, set_cwd, 1) ->
diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml
index 2044b074ee..64cdd3a8ea 100644
--- a/lib/kernel/doc/src/file.xml
+++ b/lib/kernel/doc/src/file.xml
@@ -603,8 +603,10 @@ f.txt:  {person, "kalle", 25}.
       <type>
         <v>Filename = name()</v>
         <v>Modes = [Mode]</v>
-        <v>&nbsp;Mode = read | write | append | exclusive | raw | binary | {delayed_write, Size, Delay} | delayed_write | {read_ahead, Size} | read_ahead | compressed</v>
+        <v>&nbsp;Mode = read | write | append | exclusive | raw | binary | {delayed_write, Size, Delay} | delayed_write | {read_ahead, Size} | read_ahead | compressed | {encoding, Encoding}</v>
         <v>&nbsp;&nbsp;Size = Delay = int()</v>
+	<v>&nbsp;&nbsp;Encoding = latin1 | unicode | utf8 | utf16 | {utf16, Endian} | utf32 | {utf32, Endian}</v>
+        <v>&nbsp;&nbsp;&nbsp;&nbsp;Endian = big | little</v>
         <v>IoDevice = io_device()</v>
         <v>Reason = ext_posix() | system_limit</v>
       </type>
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index cffe4e3db5..97d914b043 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -81,19 +81,28 @@
 -type io_device() :: pid() | fd().
 -type location()  :: integer() | {'bof', integer()} | {'cur', integer()}
 		   | {'eof', integer()} | 'bof' | 'cur' | 'eof'.
--type mode()      :: 'read' | 'write' | 'append' | 'raw' | 'binary' | 
-		     {'delayed_write', non_neg_integer(), non_neg_integer()} | 
-		     'delayed_write' | {'read_ahead', pos_integer()} | 
-		     'read_ahead' | 'compressed' | 'exclusive'.
+-type mode()      :: 'read' | 'write' | 'append'
+                   | 'exclusive' | 'raw' | 'binary'
+		   | {'delayed_write', non_neg_integer(), non_neg_integer()}
+		   | 'delayed_write' | {'read_ahead', pos_integer()}
+		   | 'read_ahead' | 'compressed'
+		   | {'encoding', unicode:encoding()}.
 -type name()      :: string() | atom() | [name()].
--type posix()     :: atom().
+-type posix()     :: 'eacces'  | 'eagain'  | 'ebadf'   | 'ebusy'  | 'edquot'
+		   | 'eexist'  | 'efault'  | 'efbig'   | 'eintr'  | 'einval'
+		   | 'eio'     | 'eisdir'  | 'eloop'   | 'emfile' | 'emlink'
+		   | 'enametoolong'
+		   | 'enfile'  | 'enodev'  | 'enoent'  | 'enomem' | 'enospc'
+		   | 'enotblk' | 'enotdir' | 'enotsup' | 'enxio'  | 'eperm'
+		   | 'epipe'   | 'erofs'   | 'espipe'  | 'esrch'  | 'estale'
+		   | 'exdev'.
 -type bindings()  :: any().
 
 -type date()      :: {pos_integer(), pos_integer(), pos_integer()}.
 -type time()      :: {non_neg_integer(), non_neg_integer(), non_neg_integer()}.
 -type date_time() :: {date(), time()}.
--type posix_file_advise() :: 'normal' | 'sequential' | 'random' | 'no_reuse' |
-                            'will_need' | 'dont_need'.
+-type posix_file_advise() :: 'normal' | 'sequential' | 'random'
+                           | 'no_reuse' | 'will_need' | 'dont_need'.
 
 %%%-----------------------------------------------------------------
 %%% General functions
@@ -286,7 +295,7 @@ raw_write_file_info(Name, #file_info{} = Info) ->
 %% Contemporary mode specification - list of options
 
 -spec open(Name :: name(), Modes :: [mode()]) ->
-	{'ok', io_device()} | {'error', posix()}.
+	{'ok', io_device()} | {'error', posix() | 'system_limit'}.
 
 open(Item, ModeList) when is_list(ModeList) ->
     case lists:member(raw, ModeList) of
diff --git a/lib/stdlib/src/unicode.erl b/lib/stdlib/src/unicode.erl
index 09b1deff9c..869505ba83 100644
--- a/lib/stdlib/src/unicode.erl
+++ b/lib/stdlib/src/unicode.erl
@@ -25,8 +25,17 @@
 %%                         InEncoding is not {latin1 | unicode | utf8})
 %%
 
--export([characters_to_list/1, characters_to_list_int/2, characters_to_binary/1,characters_to_binary_int/2, characters_to_binary/3,bom_to_encoding/1, encoding_to_bom/1]).
+-export([characters_to_list/1, characters_to_list_int/2,
+	 characters_to_binary/1, characters_to_binary_int/2,
+	 characters_to_binary/3,
+	 bom_to_encoding/1, encoding_to_bom/1]).
 
+-export_type([encoding/0]).
+
+-type encoding()  :: 'latin1' | 'unicode' | 'utf8'
+                   | 'utf16' | {'utf16', endian()}
+                   | 'utf32' | {'utf32', endian()}.
+-type endian()    :: 'big' | 'little'.
 
 characters_to_list(ML) ->
     unicode:characters_to_list(ML,unicode).