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
|
/** @file chert_synonym.h
* @brief Synonym data for a chert database.
*/
/* Copyright (C) 2005,2007,2008,2009,2011 Olly Betts
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef XAPIAN_INCLUDED_CHERT_SYNONYM_H
#define XAPIAN_INCLUDED_CHERT_SYNONYM_H
#include <xapian/types.h>
#include "backends/alltermslist.h"
#include "backends/database.h"
#include "chert_lazytable.h"
#include "api/termlist.h"
#include <set>
#include <string>
class ChertSynonymTable : public ChertLazyTable {
/// The last term which was updated.
mutable std::string last_term;
/// The synonyms for the last term which was updated.
mutable std::set<std::string> last_synonyms;
public:
/** Create a new ChertSynonymTable object.
*
* This method does not create or open the table on disk - you
* must call the create() or open() methods respectively!
*
* @param dbdir The directory the chert database is stored in.
* @param readonly true if we're opening read-only, else false.
*/
ChertSynonymTable(const std::string & dbdir, bool readonly)
: ChertLazyTable("synonym", dbdir + "/synonym.", readonly,
Z_DEFAULT_STRATEGY) { }
// Merge in batched-up changes.
void merge_changes();
// Discard batched-up changes.
void discard_changes() {
last_term.resize(0);
last_synonyms.clear();
}
/** Add a synonym for @a term.
*
* If the synonym has already been added, no action is taken.
*/
void add_synonym(const std::string & term, const std::string & synonym);
/** Remove a synonym for @a term.
*
* If the synonym doesn't exist, no action is taken.
*/
void remove_synonym(const std::string & term, const std::string & synonym);
/** Remove all synonyms for @a term.
*
* If @a term has no synonyms, no action is taken.
*/
void clear_synonyms(const std::string & term);
/** Open synonym termlist for a term.
*
* If @a term has no synonyms, NULL is returned.
*/
TermList * open_termlist(const std::string & term);
/** Override methods of ChertTable.
*
* NB: these aren't virtual, but we always call them on the subclass in
* cases where it matters.
* @{
*/
bool is_modified() const {
return !last_term.empty() || ChertTable::is_modified();
}
void flush_db() {
merge_changes();
ChertTable::flush_db();
}
void cancel() {
discard_changes();
ChertTable::cancel();
}
// @}
};
class ChertCursor;
class ChertSynonymTermList : public AllTermsList {
/// Copying is not allowed.
ChertSynonymTermList(const ChertSynonymTermList &);
/// Assignment is not allowed.
void operator=(const ChertSynonymTermList &);
/// Keep a reference to our database to stop it being deleted.
Xapian::Internal::intrusive_ptr<const Xapian::Database::Internal> database;
/** A cursor which runs through the synonym table reading termnames from
* the keys.
*/
ChertCursor * cursor;
/// The prefix to restrict the terms to.
string prefix;
public:
ChertSynonymTermList(Xapian::Internal::intrusive_ptr<const Xapian::Database::Internal> database_,
ChertCursor * cursor_,
const string & prefix_)
: database(database_), cursor(cursor_), prefix(prefix_)
{
// Position the cursor on the highest key before the first key we want,
// so that the first call to next() will put us on the first key we
// want.
if (prefix.empty()) {
cursor->find_entry(string());
} else {
// Seek to the first key before one with the desired prefix.
cursor->find_entry_lt(prefix);
}
}
/// Destructor.
~ChertSynonymTermList();
/** Returns the current termname.
*
* Either next() or skip_to() must have been called before this
* method can be called.
*/
string get_termname() const;
/// Return the term frequency for the term at the current position.
Xapian::doccount get_termfreq() const;
/// Return the collection frequency for the term at the current position.
Xapian::termcount get_collection_freq() const;
/// Advance to the next term in the list.
TermList * next();
/// Advance to the first term which is >= tname.
TermList * skip_to(const string &tname);
/// True if we're off the end of the list
bool at_end() const;
};
#endif // XAPIAN_INCLUDED_CHERT_SYNONYM_H
|
