FFI::Struct and FFI::Union do not call member struct's initialize method
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Key: JRUBY-4139
URL: http://jira.codehaus.org/browse/JRUBY-4139
Project: JRuby
Issue Type: Bug
Components: Extensions
Affects Versions: JRuby 1.4.0RC2, JRuby 1.3.1
Reporter: John Croisant
Priority: Minor
If you define an FFI::Struct-based or FFI::Union-based class with a
FFI::Struct-based class (let's call it MyStruct) as a member in the
struct/union, then use the #[] instance method to access the member, it returns
an instance of MyStruct. This is good.
But with JRuby, MyStruct#initialize is never actually called for the new
MyClass instance when it is created. This is bad. In my case, the #initialize
method was supposed to initialize some instance variables. But it was never
called, so the variables were never initialized, which led to mysterious
breakage elsewhere in the program.
Code says it most clearly:
{noformat}
require 'ffi'
class MyStruct < FFI::Struct
layout :a, :int
def initialize( *args )
puts "Called MyStruct#initialize for #{self.inspect}"
super
end
end
class OtherStruct < FFI::Struct
layout :mystruct, MyStruct
end
ostruct = OtherStruct.new( FFI::MemoryPointer.new(:int) )
puts "Accessing ostruct[:mystruct]..."
p ostruct[:mystruct]
class MyUnion < FFI::Union
layout :mystruct, MyStruct
end
myunion = MyUnion.new( FFI::MemoryPointer.new(:int) )
puts "Accessing myunion[:mystruct]..."
p myunion[:mystruct]
{noformat}
* Expected: When run, the script should print:
{noformat}
Accessing ostruct[:mystruct]...
Called MyStruct#initialize for #<MyStruct:0xb7728488>
#<MyStruct:0xb7728488>
Accessing myunion[:mystruct]...
Called MyStruct#initialize for #<MyStruct:0xb77281e0>
#<MyStruct:0xb77281e0>
{noformat}
* Observed: When run with JRuby 1.4.0 RC2 (and 1.3.1, and perhaps earlier), the
script prints only:
{noformat}
Accessing ostruct[:mystruct]...
#<MyStruct:0x1f2f70a>
Accessing myunion[:mystruct]...
#<MyStruct:0x6bd9e0>
{noformat}
Which indicates that MyStruct#initialize is not being called, despite new
instances of MyStruct being created.
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