jruby · Jan 3, 2016 · Jan 4, 2016
diff --git a/core/src/main/java/org/jruby/ast/RootNode.java b/core/src/main/java/org/jruby/ast/RootNode.java
@@ -48,8 +48,13 @@ public class RootNode extends Node {
     private StaticScope staticScope;
     private Node bodyNode;
     private String file;
+    private int endPosition;
 
     public RootNode(ISourcePosition position, DynamicScope scope, Node bodyNode, String file) {
+        this(position, scope, bodyNode, file, -1);
+    }
+
+    public RootNode(ISourcePosition position, DynamicScope scope, Node bodyNode, String file, int endPosition) {
         super(position, bodyNode.containsVariableAssignment());
 
         assert bodyNode != null : "bodyNode is not null";
@@ -58,6 +63,7 @@ public RootNode(ISourcePosition position, DynamicScope scope, Node bodyNode, Str
         this.staticScope = scope.getStaticScope();
         this.bodyNode = bodyNode;
         this.file = file;
+        this.endPosition = endPosition;
     }
 
     public NodeType getNodeType() {
@@ -108,4 +114,12 @@ public <T> T accept(NodeVisitor<T> iVisitor) {
     public List<Node> childNodes() {
         return createList(bodyNode);
     }
+
+    public boolean hasEndPosition() {
+        return endPosition != -1;
+    }
+
+    public int getEndPosition() {
+        return endPosition;
+    }
 }
diff --git a/core/src/main/java/org/jruby/lexer/yacc/RubyLexer.java b/core/src/main/java/org/jruby/lexer/yacc/RubyLexer.java
@@ -420,6 +420,7 @@ public final void reset() {
     private int ruby_sourceline = 0;
     private int heredoc_end = 0;
     private int line_count = 0;
+    private int line_offset = 0;
 
     /**
      * Has lexing started yet?
@@ -438,6 +439,8 @@ public int p(int offset) {
 
     public int nextc() {
         if (lex_p == lex_pend) {
+            line_offset += lex_pend;
+
             ByteList v = lex_nextline;
             lex_nextline = null;
 
@@ -1501,6 +1504,7 @@ private int yylex() throws IOException {
                 return at();
             case '_':
                 if (was_bol() && whole_match_p(END_MARKER, false)) {
+                    line_offset += lex_pend;
                     __end__seen = true;
                     eofp = true;
 
@@ -2952,4 +2956,9 @@ private char scanOct(int count) throws IOException {
 
         return value;
     }
+
+    public int getLineOffset() {
+        return line_offset;
+    }
+
 }
diff --git a/core/src/main/java/org/jruby/parser/ParserSupport.java b/core/src/main/java/org/jruby/parser/ParserSupport.java
@@ -185,6 +185,14 @@ public Node newline_node(Node node, ISourcePosition position) {
     }
 
     public Node addRootNode(Node topOfAST) {
+        final int endPosition;
+
+        if (lexer.isEndSeen()) {
+            endPosition = lexer.getLineOffset();
+        } else {
+            endPosition = -1;
+        }
+
         if (result.getBeginNodes().isEmpty()) {
             ISourcePosition position;
             if (topOfAST == null) {
@@ -194,7 +202,7 @@ public Node addRootNode(Node topOfAST) {
                 position = topOfAST.getPosition();
             }
 
-            return new RootNode(position, result.getScope(), topOfAST, lexer.getFile());
+            return new RootNode(position, result.getScope(), topOfAST, lexer.getFile(), endPosition);
         }
 
         ISourcePosition position = topOfAST != null ? topOfAST.getPosition() : result.getBeginNodes().get(0).getPosition();
@@ -206,7 +214,7 @@ public Node addRootNode(Node topOfAST) {
         // Add real top to new top (unless this top is empty [only begin/end nodes or truly empty])
         if (topOfAST != null) newTopOfAST.add(topOfAST);
 
-        return new RootNode(position, result.getScope(), newTopOfAST, lexer.getFile());
+        return new RootNode(position, result.getScope(), newTopOfAST, lexer.getFile(), endPosition);
     }
 
     /* MRI: block_append */

diff --git a/spec/truffle/tags/language/predefined/data_tags.txt b/spec/truffle/tags/language/predefined/data_tags.txt
@@ -3,7 +3,3 @@ slow:The DATA constant does not exist when the main script contains no __END__
 slow:The DATA constant does not exist when an included file has a __END__
 slow:The DATA constant does not change when an included files also has a __END__
 slow:The DATA constant is included in an otherwise empty file
-fails:The DATA constant succeeds in locking the file DATA came from
-fails:The DATA constant does not change when an included files also has a __END__
-fails:The DATA constant is included in an otherwise empty file
-fails:The DATA constant exists when the main script contains __END__
diff --git a/truffle/src/main/java/org/jruby/truffle/runtime/RubyContext.java b/truffle/src/main/java/org/jruby/truffle/runtime/RubyContext.java
@@ -605,6 +605,11 @@ public Object execute(final org.jruby.ast.RootNode rootNode) {
 
         final RubyRootNode newRootNode = originalRootNode.withBody(wrappedBody);
 
+        if (rootNode.hasEndPosition()) {
+            final Object data = inlineRubyHelper(null, "Truffle::Primitive.get_data(file, offset)", "file", StringOperations.createString(this, ByteList.create(inputFile)), "offset", rootNode.getEndPosition());
+            Layouts.MODULE.getFields(coreLibrary.getObjectClass()).setConstant(this, null, "DATA", data);
+        }
+
         return execute(ParserContext.TOP_LEVEL, DeclarationContext.TOP_LEVEL, newRootNode, null, coreLibrary.getMainObject());
     }
 

diff --git a/truffle/src/main/ruby/core/shims.rb b/truffle/src/main/ruby/core/shims.rb
@@ -1,4 +1,4 @@
-# Copyright (c) 2014, 2015 Oracle and/or its affiliates. All rights reserved. This
+# Copyright (c) 2014, 2016 Oracle and/or its affiliates. All rights reserved. This
 # code is released under a tri EPL/GPL/LGPL license. You can use it,
 # redistribute it and/or modify it under the terms of the:
 #
@@ -261,3 +261,21 @@ module Enumerable
 # JRuby uses this for example to make proxy settings visible to stdlib/uri/common.rb
 
 ENV_JAVA = {}
+
+# Truffle::Primitive.get_data is used by RubyContext#execute to prepare the DATA constant
+
+module Truffle::Primitive
+  def self.get_data(path, offset)
+    file = File.open(path)
+    file.seek(offset)
+
+    # I think if the file can't be locked then we just silently ignore
+    file.flock(File::LOCK_EX | File::LOCK_NB)
+
+    Truffle::Primitive.at_exit true do
+      file.flock(File::LOCK_UN)
+    end
+
+    file
+  end
+end