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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 #include "qcommonsequencetypes_p.h" |
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43 #include "qemptysequence_p.h" |
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44 #include "qgenericsequencetype_p.h" |
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45 #include "qitemmappingiterator_p.h" |
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46 #include "qoptimizationpasses_p.h" |
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47 #include "qsequencemappingiterator_p.h" |
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48 |
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49 #include "qforclause_p.h" |
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50 |
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51 QT_BEGIN_NAMESPACE |
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52 |
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53 using namespace QPatternist; |
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54 |
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55 ForClause::ForClause(const VariableSlotID varSlot, |
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56 const Expression::Ptr &bindingSequence, |
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57 const Expression::Ptr &returnExpression, |
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58 const VariableSlotID positionSlot) : PairContainer(bindingSequence, returnExpression), |
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59 m_varSlot(varSlot), |
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60 m_positionSlot(positionSlot), |
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61 m_allowsMany(true) |
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62 { |
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63 Q_ASSERT(m_positionSlot > -2); |
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64 } |
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65 |
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66 Item ForClause::mapToItem(const Item &item, |
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67 const DynamicContext::Ptr &context) const |
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68 { |
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69 context->setRangeVariable(m_varSlot, item); |
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70 return m_operand2->evaluateSingleton(context); |
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71 } |
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72 |
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73 Item::Iterator::Ptr ForClause::mapToSequence(const Item &item, |
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74 const DynamicContext::Ptr &context) const |
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75 { |
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76 context->setRangeVariable(m_varSlot, item); |
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77 return m_operand2->evaluateSequence(context); |
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78 } |
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79 |
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80 void ForClause::riggPositionalVariable(const DynamicContext::Ptr &context, |
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81 const Item::Iterator::Ptr &source) const |
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82 { |
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83 if(m_positionSlot > -1) |
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84 context->setPositionIterator(m_positionSlot, source); |
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85 } |
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86 |
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87 Item::Iterator::Ptr ForClause::evaluateSequence(const DynamicContext::Ptr &context) const |
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88 { |
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89 const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); |
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90 |
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91 riggPositionalVariable(context, source); |
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92 |
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93 if(m_allowsMany) |
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94 { |
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95 return makeSequenceMappingIterator<Item>(ConstPtr(this), |
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96 source, |
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97 context); |
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98 } |
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99 else |
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100 { |
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101 return makeItemMappingIterator<Item>(ConstPtr(this), |
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102 source, |
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103 context); |
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104 } |
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105 } |
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106 |
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107 Item ForClause::evaluateSingleton(const DynamicContext::Ptr &context) const |
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108 { |
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109 return evaluateSequence(context)->next(); |
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110 } |
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111 |
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112 void ForClause::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const |
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113 { |
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114 Item::Iterator::Ptr it; |
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115 const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); |
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116 |
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117 riggPositionalVariable(context, source); |
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118 |
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119 Item next(source->next()); |
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120 |
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121 while(next) |
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122 { |
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123 context->setRangeVariable(m_varSlot, next); |
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124 m_operand2->evaluateToSequenceReceiver(context); |
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125 next = source->next(); |
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126 } |
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127 } |
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128 |
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129 Expression::Ptr ForClause::typeCheck(const StaticContext::Ptr &context, |
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130 const SequenceType::Ptr &reqType) |
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131 { |
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132 const Expression::Ptr me(PairContainer::typeCheck(context, reqType)); |
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133 const Cardinality card(m_operand1->staticType()->cardinality()); |
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134 |
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135 /* If our source is empty we will always evaluate to the empty sequence, so rewrite. */ |
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136 if(card.isEmpty()) |
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137 return EmptySequence::create(this, context); |
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138 else |
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139 return me; |
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140 |
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141 /* This breaks because the variable references haven't rewritten themselves, so |
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142 * they dangle. When this is fixed, evaluateSingleton can be removed. */ |
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143 /* |
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144 else if(card->allowsMany()) |
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145 return me; |
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146 else |
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147 return m_operand2; |
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148 */ |
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149 } |
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150 |
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151 Expression::Ptr ForClause::compress(const StaticContext::Ptr &context) |
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152 { |
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153 const Expression::Ptr me(PairContainer::compress(context)); |
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154 if(me != this) |
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155 return me; |
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156 |
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157 /* This is done after calling PairContainer::typeCheck(). The advantage of this is that |
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158 * m_allowsMany is updated according to what the operand says after it has compressed. However, |
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159 * if it was initialized to false(as it once was..), ForClause::evaluateSequence() |
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160 * would potentially have been called by PairContainer::compress(), and it would have |
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161 * used an unsafe branch. */ |
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162 m_allowsMany = m_operand2->staticType()->cardinality().allowsMany(); |
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163 |
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164 return me; |
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165 } |
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166 |
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167 SequenceType::Ptr ForClause::staticType() const |
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168 { |
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169 const SequenceType::Ptr returnType(m_operand2->staticType()); |
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170 |
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171 return makeGenericSequenceType(returnType->itemType(), |
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172 m_operand1->staticType()->cardinality() |
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173 * /* multiply operator */ |
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174 returnType->cardinality()); |
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175 } |
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176 |
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177 SequenceType::List ForClause::expectedOperandTypes() const |
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178 { |
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179 SequenceType::List result; |
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180 result.append(CommonSequenceTypes::ZeroOrMoreItems); |
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181 result.append(CommonSequenceTypes::ZeroOrMoreItems); |
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182 return result; |
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183 } |
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184 |
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185 ExpressionVisitorResult::Ptr ForClause::accept(const ExpressionVisitor::Ptr &visitor) const |
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186 { |
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187 return visitor->visit(this); |
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188 } |
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189 |
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190 OptimizationPass::List ForClause::optimizationPasses() const |
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191 { |
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192 return OptimizationPasses::forPasses; |
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193 } |
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194 |
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195 Expression::ID ForClause::id() const |
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196 { |
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197 return IDForClause; |
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198 } |
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199 |
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200 QT_END_NAMESPACE |