1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
#
# Copyright (C) 2008, 2009 Wayne Meissner
# Copyright (C) 2008 Mike Dalessio
#
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# * Neither the name of the Evan Phoenix nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
module FFI
class AutoPointer < Pointer
# call-seq:
# AutoPointer.new(pointer, method) => the passed Method will be invoked at GC time
# AutoPointer.new(pointer, proc) => the passed Proc will be invoked at GC time (SEE WARNING BELOW!)
# AutoPointer.new(pointer) { |p| ... } => the passed block will be invoked at GC time (SEE WARNING BELOW!)
# AutoPointer.new(pointer) => the pointer's release() class method will be invoked at GC time
#
# WARNING: passing a proc _may_ cause your pointer to never be GC'd, unless you're careful to avoid trapping a reference to the pointer in the proc. See the test specs for examples.
# WARNING: passing a block will cause your pointer to never be GC'd. This is bad.
#
# Please note that the safest, and therefore preferred, calling
# idiom is to pass a Method as the second parameter. Example usage:
#
# class PointerHelper
# def self.release(pointer)
# ...
# end
# end
#
# p = AutoPointer.new(other_pointer, PointerHelper.method(:release))
#
# The above code will cause PointerHelper#release to be invoked at GC time.
#
# The last calling idiom (only one parameter) is generally only
# going to be useful if you subclass AutoPointer, and override
# release(), which by default does nothing.
#
def initialize(ptr, proc=nil, &block)
raise TypeError, "Invalid pointer" if ptr.nil? || !ptr.kind_of?(Pointer) \
|| ptr.kind_of?(MemoryPointer) || ptr.kind_of?(AutoPointer)
@releaser = if proc
raise RuntimeError.new("proc must be callable") unless proc.respond_to?(:call)
CallableReleaser.new(ptr, proc)
else
raise RuntimeError.new("no release method defined") unless self.class.respond_to?(:release)
DefaultReleaser.new(ptr, self.class)
end
self.parent = ptr
ObjectSpace.define_finalizer(self, @releaser)
self
end
def free
@releaser.free
end
def autorelease=(autorelease)
@releaser.autorelease=(autorelease)
end
class Releaser
def initialize(ptr, proc)
@ptr = ptr
@proc = proc
@autorelease = true
end
def free
raise RuntimeError.new("pointer already freed") unless @ptr
@autorelease = false
@ptr = nil
@proc = nil
end
def autorelease=(autorelease)
raise RuntimeError.new("pointer already freed") unless @ptr
@autorelease = autorelease
end
end
class DefaultReleaser < Releaser
def call(*args)
@proc.release(@ptr) if @autorelease && @ptr
end
end
class CallableReleaser < Releaser
def call(*args)
@proc.call(@ptr) if @autorelease && @ptr
end
end
end
end
|
