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Fix Fiddle::Pointer#ref behavior for FFI backend #185

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Merged
kou merged 2 commits into from
Apr 23, 2025
Merged

Fix Fiddle::Pointer#ref behavior for FFI backend #185

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5ef1e52
Fix Fiddle::Pointer#ref behavior for FFI backend
ankane Apr 23, 2025
7467470
Add note about pointer thread safety for FFI backend [skip ci]
ankane Apr 23, 2025
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25 changes: 14 additions & 11 deletions lib/fiddle/ffi_backend.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -218,8 +218,8 @@ class Error < StandardError; end
class DLError < Error; end
class ClearedReferenceError < Error; end

# Pointer isn't thread safe for now
class Pointer
attr_reader :ffi_ptr
extend FFI::DataConverter
native_type FFI::Type::Builtin::POINTER

Expand Down Expand Up @@ -285,15 +285,15 @@ def []=(*args, value)
value = value.to_str(args[1])
end

@ffi_ptr.put_bytes(args[0], value, 0, args[1])
ffi_ptr.put_bytes(args[0], value, 0, args[1])
elsif args.size == 1
if value.is_a?(Fiddle::Pointer)
value = value.to_str(args[0] + 1)
else
value = value.chr
end

@ffi_ptr.put_bytes(args[0], value, 0, 1)
ffi_ptr.put_bytes(args[0], value, 0, 1)
end
rescue FFI::NullPointerError
raise DLError.new("NULL pointer access")
Expand Down Expand Up @@ -332,9 +332,14 @@ def initialize(addr, size = nil, free = nil)
end
@free = free
@ffi_ptr = ptr
@addr_ptr = nil
@freed = false
end

def ffi_ptr
@addr_ptr ? @addr_ptr.get_pointer(0) : @ffi_ptr
end

module LibC
extend FFI::Library
ffi_lib FFI::Library::LIBC
Expand Down Expand Up @@ -363,11 +368,11 @@ def self.malloc(size, free = nil)
end

def null?
@ffi_ptr.null?
ffi_ptr.null?
end

def to_ptr
@ffi_ptr
ffi_ptr
end

def size
Expand All @@ -386,9 +391,9 @@ def call_free
return if @free.nil?
return if @freed
if @free == RUBY_FREE
LibC::FREE.call(@ffi_ptr)
LibC::FREE.call(ffi_ptr)
else
@free.call(@ffi_ptr)
@free.call(ffi_ptr)
end
@freed = true
end
Expand Down Expand Up @@ -492,10 +497,8 @@ def -@
end

def ref
cptr = Pointer.malloc(FFI::Type::POINTER.size, RUBY_FREE)
cptr.ffi_ptr.put_pointer(0, ffi_ptr)
cptr.size = 0
cptr
@addr_ptr ||= FFI::MemoryPointer.new(:pointer).put_pointer(0, @ffi_ptr)
Pointer.new(@addr_ptr, 0)
end
end

Expand Down
13 changes: 13 additions & 0 deletions test/fiddle/test_pointer.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -187,6 +187,19 @@ def test_cmp
assert_nil(ptr <=> 10, '10 should not be comparable')
end

def test_ref
ptr = Fiddle::Pointer["hello"]
ref = ptr.ref
assert_equal(0, ref.size)
assert_nil(ref.free)
assert_equal(ptr, ref.ptr)

ptr2 = Fiddle::Pointer["world"]
ptr.ref[0, Fiddle::SIZEOF_VOIDP] = ptr2.ref
assert_equal("world", ptr.to_s)
assert_equal(ptr.to_i, ptr2.to_i)
end

def test_ref_ptr
if ffi_backend?
omit("Fiddle.dlwrap([]) isn't supported with FFI backend")
Expand Down