forked from mozilla/gecko-dev
-
Notifications
You must be signed in to change notification settings - Fork 2
/
StatementCache.h
186 lines (166 loc) · 5.63 KB
/
StatementCache.h
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
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the mozStorage statement cache.
*
* The Initial Developer of the Original Code is
* the Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Shawn Wilsher <me@shawnwilsher.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef mozilla_storage_StatementCache_h
#define mozilla_storage_StatementCache_h
#include "mozIStorageConnection.h"
#include "mozIStorageStatement.h"
#include "mozIStorageAsyncStatement.h"
#include "nsAutoPtr.h"
#include "nsHashKeys.h"
#include "nsInterfaceHashtable.h"
namespace mozilla {
namespace storage {
/**
* Class used to cache statements (mozIStorageStatement or
* mozIStorageAsyncStatement).
*/
template<typename StatementType>
class StatementCache {
public:
/**
* Constructor for the cache.
*
* @note a connection can have more than one cache.
*
* @param aConnection
* A reference to the nsCOMPtr for the connection this cache is to be
* used for. This nsCOMPtr must at least live as long as this class,
* otherwise crashes will happen.
*/
StatementCache(nsCOMPtr<mozIStorageConnection>& aConnection)
: mConnection(aConnection)
{
if (!mCachedStatements.Init()) {
NS_ERROR("Out of memory!?");
}
}
/**
* Obtains a cached statement. If this statement is not yet created, it will
* be created and stored for later use.
*
* @param aQuery
* The SQL string (either a const char [] or nsACString) to get a
* cached query for.
* @return the cached statement, or null upon error.
*/
inline
already_AddRefed<StatementType>
GetCachedStatement(const nsACString& aQuery)
{
nsCOMPtr<StatementType> stmt;
if (!mCachedStatements.Get(aQuery, getter_AddRefs(stmt))) {
stmt = CreateStatement(aQuery);
NS_ENSURE_TRUE(stmt, nsnull);
if (!mCachedStatements.Put(aQuery, stmt)) {
NS_ERROR("Out of memory!?");
}
}
return stmt.forget();
}
template<int N>
NS_ALWAYS_INLINE already_AddRefed<StatementType>
GetCachedStatement(const char (&aQuery)[N])
{
nsDependentCString query(aQuery, N - 1);
return GetCachedStatement(query);
}
/**
* Finalizes all cached statements so the database can be safely closed. The
* behavior of this cache is unspecified after this method is called.
*/
inline
void
FinalizeStatements()
{
(void)mCachedStatements.Enumerate(FinalizeCachedStatements, NULL);
// Clear the cache at this time too!
(void)mCachedStatements.Clear();
}
private:
inline
already_AddRefed<StatementType>
CreateStatement(const nsACString& aQuery);
static
PLDHashOperator
FinalizeCachedStatements(const nsACString& aKey,
nsCOMPtr<StatementType>& aStatement,
void*)
{
(void)aStatement->Finalize();
return PL_DHASH_NEXT;
}
nsInterfaceHashtable<nsCStringHashKey, StatementType> mCachedStatements;
nsCOMPtr<mozIStorageConnection>& mConnection;
};
template< >
inline
already_AddRefed<mozIStorageStatement>
StatementCache<mozIStorageStatement>::CreateStatement(const nsACString& aQuery)
{
NS_ENSURE_TRUE(mConnection, nsnull);
nsCOMPtr<mozIStorageStatement> stmt;
nsresult rv = mConnection->CreateStatement(aQuery, getter_AddRefs(stmt));
if (NS_FAILED(rv)) {
nsCString error;
error.AppendLiteral("The statement '");
error.Append(aQuery);
error.AppendLiteral("' failed to compile with the error message '");
nsCString msg;
(void)mConnection->GetLastErrorString(msg);
error.Append(msg);
error.AppendLiteral("'.");
NS_ERROR(error.get());
}
NS_ENSURE_SUCCESS(rv, nsnull);
return stmt.forget();
}
template< >
inline
already_AddRefed<mozIStorageAsyncStatement>
StatementCache<mozIStorageAsyncStatement>::CreateStatement(const nsACString& aQuery)
{
NS_ENSURE_TRUE(mConnection, nsnull);
nsCOMPtr<mozIStorageAsyncStatement> stmt;
nsresult rv = mConnection->CreateAsyncStatement(aQuery, getter_AddRefs(stmt));
NS_ENSURE_SUCCESS(rv, nsnull);
return stmt.forget();
}
} // namespace storage
} // namespace mozilla
#endif // mozilla_storage_StatementCache_h