Let escript recognize an encoding comment on the second line

The manual says that an Emacs directive can be placed on the second
line. With this patch that directive is also recognized when selecting
encoding of the script.

erts/doc/src/escript.xml

@@ -4,7 +4,7 @@
 <comref>
   <header>
     <copyright>
-      <year>2007</year><year>2011</year>
+      <year>2007</year><year>2013</year>
       <holder>Ericsson AB. All Rights Reserved.</holder>
     </copyright>
     <legalnotice>
@@ -85,6 +85,11 @@ $ <input>escript factorial 5</input>        </pre>
           enter the major mode for editing Erlang source files. If the
           directive is present it must be located on the second
           line.</p>
+
+        <p>If there is a comment selecting the <seealso
+          marker="stdlib:epp#encoding">encoding</seealso> it can be
+          located on the second line.</p>
+
 	<p>On the third line (or second line depending on the presence
           of the Emacs directive), it is possible to give arguments to
           the emulator, such as </p>
@@ -133,7 +138,9 @@ halt(1).</pre>
         <pre>
 -include_lib("kernel/include/file.hrl").</pre>
         <p>to include the record definitions for the records used by the
-          <c>file:read_link_info/1</c> function.</p>
+          <c>file:read_link_info/1</c> function. You can also select
+          encoding here, but if there is a valid encoding comment on
+          the second line it takes precedence.</p>
 
         <p>The script will be checked for syntactic and semantic
           correctness before being run. If there are warnings (such as

lib/stdlib/src/escript.erl

@@ -602,9 +602,15 @@ parse_beam(S, File, HeaderSz, CheckOnly) ->
 parse_source(S, File, Fd, StartLine, HeaderSz, CheckOnly) ->
     {PreDefMacros, Module} = pre_def_macros(File),
     IncludePath = [],
-    {ok, _} = file:position(Fd, {bof, HeaderSz}),
+    %% Read the encoding on the second line, if there is any:
+    {ok, _} = file:position(Fd, 0),
+    _ = io:get_line(Fd, ''),
+    Encoding = epp:set_encoding(Fd),
+    {ok, _} = file:position(Fd, HeaderSz),
     case epp:open(File, Fd, StartLine, IncludePath, PreDefMacros) of
         {ok, Epp} ->
+            _ = [io:setopts(Fd, [{encoding,Encoding}]) ||
+                    Encoding =/= none],
             {ok, FileForm} = epp:parse_erl_form(Epp),
             OptModRes = epp:parse_erl_form(Epp),
             S2 = S#state{source = text, module = Module},

lib/stdlib/test/escript_SUITE.erl

@@ -919,6 +919,9 @@ unicode(Config) when is_list(Config) ->
            " an arithmetic expression\n  in operator  '/'/2\n     "
            "called as <<\"\xaa\">> / <<\"\xaa\">>\nExitCode:127">>]),
     run(Dir, "unicode3", [<<"ExitCode:0">>]),
+    run(Dir, "unicode4", [<<"ExitCode:0">>]),
+    run(Dir, "unicode5", [<<"ExitCode:0">>]),
+    run(Dir, "unicode6", [<<"ExitCode:0">>]),
     ok.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

lib/stdlib/test/escript_SUITE_data/unicode3

@@ -1,5 +1,5 @@
 #!/usr/bin/env escript
-%% -*- erlang; coding: utf-8 -*-
+%% -*- erlang; coding: latin-1 -*-
 
 -export([main/1]).
 

lib/stdlib/test/escript_SUITE_data/unicode4

@@ -0,0 +1,12 @@
+#!/usr/bin/env escript
+%% -*- erlang; encoding:utf-8 -*-
+
+-export([main/1]).
+
+main(_) ->
+    ok = io:setopts([{encoding,unicode}]),
+    Bin1 = <<"örn_Ѐ שלום-שלום+של 日本語">>,
+    L = [246,114,110,95,1024,32,1513,1500,1493,1501,45,1513,1500,1493,
+         1501,43,1513,1500,32,26085,26412,35486],
+    L = unicode:characters_to_list(Bin1, utf8),
+    ok.

lib/stdlib/test/escript_SUITE_data/unicode5

@@ -0,0 +1,12 @@
+#!/usr/bin/env escript
+%% -*- erlang -*-
+-export([main/1]).
+%% -*- encoding:latin-1 -*-
+
+main(_) ->
+    ok = io:setopts([{encoding,unicode}]),
+    Bin1 = <<"örn_Ѐ שלום-שלום+של 日本語">>,
+    L = [246,114,110,95,1024,32,1513,1500,1493,1501,45,1513,1500,1493,
+         1501,43,1513,1500,32,26085,26412,35486],
+    L = unicode:characters_to_list(Bin1, utf8),
+    ok.

lib/stdlib/test/escript_SUITE_data/unicode6

@@ -0,0 +1,13 @@
+#!/usr/bin/env escript
+%% -*- erlang -*-
+%%! +pc unicode
+-export([main/1]).
+%% -*- encoding:utf-8 -*-
+
+main(_) ->
+    ok = io:setopts([{encoding,unicode}]),
+    Bin1 = <<"örn_Ѐ שלום-שלום+של 日本語">>,
+    L = [246,114,110,95,1024,32,1513,1500,1493,1501,45,1513,1500,1493,
+         1501,43,1513,1500,32,26085,26412,35486],
+    L = unicode:characters_to_list(Bin1, utf8),
+    ok.