1 /*
2 Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License, version 2.0,
6 as published by the Free Software Foundation.
7
8 This program is also distributed with certain software (including
9 but not limited to OpenSSL) that is licensed under separate terms,
10 as designated in a particular file or component or in included license
11 documentation. The authors of MySQL hereby grant you an additional
12 permission to link the program and your derivative works with the
13 separately licensed software that they have included with MySQL.
14
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License, version 2.0, for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #ifndef WOPOOL_HPP
26 #define WOPOOL_HPP
27
28 #include "Pool.hpp"
29
30 struct WOPage
31 {
32 STATIC_CONST( WOPAGE_WORDS = GLOBAL_PAGE_SIZE_WORDS - 2 );
33
34 Uint32 m_type_id;
35 Uint32 m_ref_count;
36 Uint32 m_data[WOPAGE_WORDS];
37 };
38
39 /**
40 * Write Once Pool
41 */
42 struct WOPool
43 {
44 Record_info m_record_info;
45 WOPage* m_memroot;
46 WOPage* m_current_page;
47 Pool_context m_ctx;
48 Uint32 m_current_page_no;
49 Uint16 m_current_pos;
50 Uint16 m_current_ref_count;
51 public:
52 WOPool();
53
54 void init(const Record_info& ri, const Pool_context& pc);
55 bool seize(Ptr<void>&);
56 void release(Ptr<void>);
57 void * getPtr(Uint32 i);
58
59 private:
60 bool seize_new_page(Ptr<void>&);
61 void release_not_current(Ptr<void>);
62
63 void handle_invalid_release(Ptr<void>) ATTRIBUTE_NORETURN;
64 void handle_invalid_get_ptr(Uint32 i) ATTRIBUTE_NORETURN;
65 void handle_inconsistent_release(Ptr<void>) ATTRIBUTE_NORETURN;
66 };
67
68 inline
69 bool
seize(Ptr<void> & ptr)70 WOPool::seize(Ptr<void>& ptr)
71 {
72 Uint32 pos = m_current_pos;
73 Uint32 size = m_record_info.m_size;
74 WOPage *pageP = m_current_page;
75 if (likely(pos + size < WOPage::WOPAGE_WORDS))
76 {
77 ptr.i = (m_current_page_no << POOL_RECORD_BITS) + pos;
78 ptr.p = (pageP->m_data + pos);
79 pageP->m_data[pos+m_record_info.m_offset_magic] = ~(Uint32)m_record_info.m_type_id;
80 m_current_pos = pos + size;
81 m_current_ref_count++;
82 return true;
83 }
84
85 return seize_new_page(ptr);
86 }
87
88 inline
89 void
release(Ptr<void> ptr)90 WOPool::release(Ptr<void> ptr)
91 {
92 Uint32 cur_page = m_current_page_no;
93 Uint32 ptr_page = ptr.i >> POOL_RECORD_BITS;
94 Uint32 *magic_ptr = (((Uint32*)ptr.p)+m_record_info.m_offset_magic);
95 Uint32 magic_val = *magic_ptr;
96
97 if (likely(magic_val == ~(Uint32)m_record_info.m_type_id))
98 {
99 * magic_ptr = 0;
100 if (cur_page == ptr_page)
101 {
102 if (m_current_ref_count == 1)
103 {
104 m_current_pos = 0;
105 }
106 m_current_ref_count--;
107 return;
108 }
109 return release_not_current(ptr);
110 }
111 handle_invalid_release(ptr);
112 }
113
114 inline
115 void*
getPtr(Uint32 i)116 WOPool::getPtr(Uint32 i)
117 {
118 Uint32 page_no = i >> POOL_RECORD_BITS;
119 Uint32 page_idx = i & POOL_RECORD_MASK;
120 WOPage * page = m_memroot + page_no;
121 Uint32 * record = page->m_data + page_idx;
122 Uint32 magic_val = * (record + m_record_info.m_offset_magic);
123 if (likely(magic_val == ~(Uint32)m_record_info.m_type_id))
124 {
125 return record;
126 }
127 handle_invalid_get_ptr(i);
128 return 0; /* purify: deadcode */
129 }
130
131 #endif
132