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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
#
# Copyright (C) 2008-2010 Wayne Meissner
# Copyright (C) 2008 Mike Dalessio
#
# This file is part of ruby-ffi.
#
# 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 Ruby FFI project 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
extend DataConverter
# @overload initialize(pointer, method)
# @param pointer [Pointer]
# @param method [Method]
# @return [self]
# The passed Method will be invoked at GC time.
# @overload initialize(pointer, proc)
# @param pointer [Pointer]
# @return [self]
# The passed Proc will be invoked at GC time (SEE WARNING BELOW!)
# @note 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.
# @overload initialize(pointer) { |p| ... }
# @param pointer [Pointer]
# @yieldparam [Pointer] p +pointer+ passed to the block
# @return [self]
# The passed block will be invoked at GC time.
# @note
# WARNING: passing a block will cause your pointer to never be GC'd.
# This is bad.
# @overload initialize(pointer)
# @param pointer [Pointer]
# @return [self]
# The pointer's release() class method will be invoked at GC time.
#
# @note 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.
#
# @note
# 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)
super(ptr.type_size, ptr)
@releaser = if proc
if not proc.respond_to?(:call)
raise RuntimeError.new("proc must be callable")
end
Releaser.new(ptr, proc)
else
if not self.class.respond_to?(:release, true)
raise RuntimeError.new("no release method defined")
end
Releaser.new(ptr, self.class.method(:release))
end
ObjectSpace.define_finalizer(self, @releaser)
self
end
# @return [nil]
# Free the pointer.
def free
@releaser.free
end
# @param [Boolean] autorelease
# @return [Boolean] +autorelease+
# Set +autorelease+ property. See {Pointer Autorelease section at Pointer}.
def autorelease=(autorelease)
raise FrozenError.new("can't modify frozen #{self.class}") if frozen?
@releaser.autorelease=(autorelease)
end
# @return [Boolean] +autorelease+
# Get +autorelease+ property. See {Pointer Autorelease section at Pointer}.
def autorelease?
@releaser.autorelease
end
# @abstract Base class for {AutoPointer}'s releasers.
#
# All subclasses of Releaser should define a +#release(ptr)+ method.
# A releaser is an object in charge of release an {AutoPointer}.
class Releaser
attr_accessor :autorelease
# @param [Pointer] ptr
# @param [#call] proc
# @return [nil]
# A new instance of Releaser.
def initialize(ptr, proc)
@ptr = ptr
@proc = proc
@autorelease = true
end
# @return [nil]
# Free pointer.
def free
if @ptr
release(@ptr)
@autorelease = false
@ptr = nil
@proc = nil
end
end
# @param args
# Release pointer if +autorelease+ is set.
def call(*args)
release(@ptr) if @autorelease && @ptr
end
# Release +ptr+ by using Proc or Method defined at +ptr+
# {AutoPointer#initialize initialization}.
#
# @param [Pointer] ptr
# @return [nil]
def release(ptr)
@proc.call(ptr)
end
end
# Return native type of AutoPointer.
#
# Override {DataConverter#native_type}.
# @return [Type::POINTER]
# @raise {RuntimeError} if class does not implement a +#release+ method
def self.native_type
if not self.respond_to?(:release, true)
raise RuntimeError.new("no release method defined for #{self.inspect}")
end
Type::POINTER
end
# Create a new AutoPointer.
#
# Override {DataConverter#from_native}.
# @overload self.from_native(ptr, ctx)
# @param [Pointer] ptr
# @param ctx not used. Please set +nil+.
# @return [AutoPointer]
def self.from_native(val, ctx)
self.new(val)
end
end
end
|
