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
|
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
#ifndef Patternist_ExternalVariableLoader_H
#define Patternist_ExternalVariableLoader_H
#include "qitem_p.h"
#include "qsequencetype_p.h"
#include "qxmlname.h"
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
namespace QPatternist
{
class DynamicContext;
/**
* @short Responsible for loading and declaring available external variables.
*
* An external variable in XQuery is a global variable that has been declared to receive
* its value from the XQuery implementation, as opposed to an initializing expression. Here
* is an example of a query with an external variable declaration, followed by a ordinary
* global variable:
*
* <tt> declare variable $theName external;
* declare variable $theName := "the value";
* "And here's the query body(a string literal)"</tt>
*
* An external variable declaration can also specify a sequence type:
*
* <tt>declare variable $theName as xs:integer external;</tt>
*
* This class allows the user to supply the values to external variables. When
* an external variable declaration occur in the query,
* announceExternalVariable() is called.
*
* @ingroup Patternist_xdm
* @author Frans Englich <frans.englich@nokia.com>
*/
class Q_AUTOTEST_EXPORT ExternalVariableLoader : public QSharedData
{
public:
typedef QExplicitlySharedDataPointer<ExternalVariableLoader> Ptr;
inline ExternalVariableLoader() {}
virtual ~ExternalVariableLoader();
/**
* Called when Patternist encounters an external variable in the query. It is guaranteed
* to be called once for each external variable appearing in a query module.
*
* @param name the name of the variable. Quaranteed to never be @c null.
* @param declaredType the type that the user declared the variable to be of. Whether
* this type matches the actual value of the variable or not is irrelevant. Patternist
* will do the necessary error handling based on the sequence type that is returned from
* this function. If the user didn't declare a type, the type is <tt>item()*</tt>(zero or
* more items). Quaranteed to never be @c null.
* @returns the sequence type of the value this ExternalVariableLoader actually supplies. However,
* if the ExternalVariableLoader knows it cannot supply a variable by this name, @c null should be
* returned.
*/
virtual SequenceType::Ptr announceExternalVariable(const QXmlName name,
const SequenceType::Ptr &declaredType);
/**
* This function is called at runtime when the external variable by name @p name needs
* to be evaluated. It is not defined how many times this function will be called. It
* depends on aspects such as how the query was optimized.
*
* @param name the name of the variable. Quaranteed to never be @c null.
* @param context the DynamicContext.
* @returns the value of the variable. Remember that this value must match the
* sequence type returned from announceExternalVariable() for the same name.
*/
virtual Item::Iterator::Ptr evaluateSequence(const QXmlName name,
const QExplicitlySharedDataPointer<DynamicContext> &context);
virtual Item evaluateSingleton(const QXmlName name,
const QExplicitlySharedDataPointer<DynamicContext> &context);
virtual bool evaluateEBV(const QXmlName name,
const QExplicitlySharedDataPointer<DynamicContext> &context);
};
}
QT_END_NAMESPACE
QT_END_HEADER
#endif
|
