1 | /* |
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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3 | * contributor license agreements. See the NOTICE file distributed with |
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4 | * this work for additional information regarding copyright ownership. |
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5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
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6 | * (the "License"); you may not use this file except in compliance with |
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7 | * the License. You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
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16 | */ |
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17 | |
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18 | /* |
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19 | * $Id: DOM_DocumentFragment.hpp 568078 2007-08-21 11:43:25Z amassari $ |
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20 | */ |
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21 | |
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22 | #ifndef DOM_DocumentFragment_HEADER_GUARD_ |
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23 | #define DOM_DocumentFragment_HEADER_GUARD_ |
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24 | |
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25 | #include <xercesc/util/XercesDefs.hpp> |
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26 | #include "DOM_Node.hpp" |
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27 | |
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28 | XERCES_CPP_NAMESPACE_BEGIN |
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29 | |
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30 | |
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31 | class DocumentFragmentImpl; |
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32 | |
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33 | /** |
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34 | * <code>DocumentFragment</code> is a "lightweight" or "minimal" |
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35 | * <code>Document</code> object. |
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36 | * |
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37 | * It is very common to want to be able to |
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38 | * extract a portion of a document's tree or to create a new fragment of a |
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39 | * document. Imagine implementing a user command like cut or rearranging a |
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40 | * document by moving fragments around. It is desirable to have an object |
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41 | * which can hold such fragments and it is quite natural to use a Node for |
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42 | * this purpose. While it is true that a <code>Document</code> object could |
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43 | * fulfil this role, a <code>Document</code> object can potentially be a |
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44 | * heavyweight object, depending on the underlying implementation. What is |
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45 | * really needed for this is a very lightweight object. |
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46 | * <code>DocumentFragment</code> is such an object. |
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47 | * <p>Furthermore, various operations -- such as inserting nodes as children |
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48 | * of another <code>Node</code> -- may take <code>DocumentFragment</code> |
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49 | * objects as arguments; this results in all the child nodes of the |
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50 | * <code>DocumentFragment</code> being moved to the child list of this node. |
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51 | * <p>The children of a <code>DocumentFragment</code> node are zero or more |
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52 | * nodes representing the tops of any sub-trees defining the structure of the |
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53 | * document. <code>DocumentFragment</code> nodes do not need to be |
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54 | * well-formed XML documents (although they do need to follow the rules |
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55 | * imposed upon well-formed XML parsed entities, which can have multiple top |
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56 | * nodes). For example, a <code>DocumentFragment</code> might have only one |
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57 | * child and that child node could be a <code>Text</code> node. Such a |
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58 | * structure model represents neither an HTML document nor a well-formed XML |
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59 | * document. |
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60 | * <p>When a <code>DocumentFragment</code> is inserted into a |
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61 | * <code>Document</code> (or indeed any other <code>Node</code> that may take |
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62 | * children) the children of the <code>DocumentFragment</code> and not the |
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63 | * <code>DocumentFragment</code> itself are inserted into the |
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64 | * <code>Node</code>. This makes the <code>DocumentFragment</code> very |
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65 | * useful when the user wishes to create nodes that are siblings; the |
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66 | * <code>DocumentFragment</code> acts as the parent of these nodes so that the |
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67 | * user can use the standard methods from the <code>Node</code> interface, |
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68 | * such as <code>insertBefore()</code> and <code>appendChild()</code>. |
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69 | */ |
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70 | |
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71 | class DEPRECATED_DOM_EXPORT DOM_DocumentFragment: public DOM_Node { |
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72 | |
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73 | public: |
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74 | /** @name Constructors and assignment operators */ |
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75 | //@{ |
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76 | /** |
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77 | * Default constructor for <code>DOM_DocumentFragment</code>. The resulting object does not |
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78 | * refer to an actual Document Fragment node; it will compare == to 0, and is similar |
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79 | * to a null object reference variable in Java. It may subsequently be |
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80 | * assigned to refer to an actual Document Fragment node. |
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81 | * <p> |
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82 | * New document fragment nodes are created by DOM_Document::createDocumentFragment(). |
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83 | * |
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84 | */ |
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85 | |
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86 | DOM_DocumentFragment(); |
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87 | |
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88 | /** |
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89 | * Copy constructor. Creates a new <code>DOM_DocumentFragment</code> that refers to the |
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90 | * same underlying node as the original. See also DOM_Node::clone(), |
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91 | * which will copy the actual Document fragment node, rather than just creating a new |
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92 | * reference to the original node. |
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93 | * |
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94 | * @param other The object to be copied |
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95 | */ |
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96 | DOM_DocumentFragment(const DOM_DocumentFragment &other); |
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97 | |
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98 | /** |
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99 | * Assignment operator |
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100 | * |
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101 | * @param other The object to be copied |
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102 | */ |
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103 | DOM_DocumentFragment & operator = (const DOM_DocumentFragment &other); |
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104 | |
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105 | /** |
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106 | * Assignment operator. This overloaded variant is provided for |
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107 | * the sole purpose of setting a DOM_Node reference variable to |
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108 | * zero. Nulling out a reference variable in this way will decrement |
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109 | * the reference count on the underlying Node object that the variable |
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110 | * formerly referenced. This effect is normally obtained when reference |
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111 | * variable goes out of scope, but zeroing them can be useful for |
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112 | * global instances, or for local instances that will remain in scope |
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113 | * for an extended time, when the storage belonging to the underlying |
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114 | * node needs to be reclaimed. |
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115 | * |
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116 | * @param val Only a value of 0, or null, is allowed. |
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117 | */ |
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118 | DOM_DocumentFragment & operator = (const DOM_NullPtr *val); |
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119 | |
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120 | //@} |
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121 | /** @name Destructor */ |
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122 | //@{ |
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123 | |
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124 | /** |
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125 | * Destructor. The object being destroyed is the reference |
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126 | * object, not the underlying Comment node itself. |
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127 | * |
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128 | */ |
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129 | ~DOM_DocumentFragment(); |
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130 | |
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131 | //@} |
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132 | |
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133 | protected: |
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134 | DOM_DocumentFragment(DocumentFragmentImpl *); |
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135 | |
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136 | friend class DOM_Document; |
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137 | friend class RangeImpl; |
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138 | }; |
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139 | |
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140 | XERCES_CPP_NAMESPACE_END |
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141 | |
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142 | #endif |
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