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diff --git a/docs/manual/modify.html b/docs/manual/modify.html new file mode 100644 index 0000000..f00e657 --- /dev/null +++ b/docs/manual/modify.html @@ -0,0 +1,541 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Modifying document data</title> +<link rel="stylesheet" href="../pugixml.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> +<link rel="home" href="../manual.html" title="pugixml 0.9"> +<link rel="up" href="../manual.html" title="pugixml 0.9"> +<link rel="prev" href="access.html" title="Accessing document data"> +<link rel="next" href="saving.html" title="Saving document"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table width="100%"><tr> +<td>pugixml 0.9 manual | + <a href="../manual.html">Overview</a> | + <a href="install.html">Installation</a> | + Document: + <a href="dom.html">Object model</a> · <a href="loading.html">Loading</a> · <a href="access.html">Accessing</a> · <b>Modifying</b> · <a href="saving.html">Saving</a> | + <a href="xpath.html">XPath</a> | + <a href="apiref.html">API Reference</a> | + <a href="toc.html">Table of Contents</a> +</td> +<td width="*" align="right"><div class="spirit-nav"> +<a accesskey="p" href="access.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../manual.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../manual.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="saving.html"><img src="../images/next.png" alt="Next"></a> +</div></td> +</tr></table> +<hr> +<div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="manual.modify"></a><a class="link" href="modify.html" title="Modifying document data"> Modifying document data</a> +</h2></div></div></div> +<div class="toc"><dl> +<dt><span class="section"><a href="modify.html#manual.modify.nodedata"> Setting node data</a></span></dt> +<dt><span class="section"><a href="modify.html#manual.modify.attrdata"> Setting attribute data</a></span></dt> +<dt><span class="section"><a href="modify.html#manual.modify.add"> Adding nodes/attributes</a></span></dt> +<dt><span class="section"><a href="modify.html#manual.modify.remove"> Removing nodes/attributes</a></span></dt> +<dt><span class="section"><a href="modify.html#manual.modify.clone"> Cloning nodes/attributes</a></span></dt> +</dl></div> +<p> + The document in pugixml is fully mutable: you can completely change the document + structure and modify the data of nodes/attributes. This section provides documentation + for the relevant functions. All functions take care of memory management and + structural integrity themselves, so they always result in structurally valid + tree - however, it is possible to create an invalid XML tree (for example, + by adding two attributes with the same name or by setting attribute/node name + to empty/invalid string). Tree modification is optimized for performance and + for memory consumption, so if you have enough memory you can create documents + from scratch with pugixml and later save them to file/stream instead of relying + on error-prone manual text writing and without too much overhead. + </p> +<p> + All member functions that change node/attribute data or structure are non-constant + and thus can not be called on constant handles. However, you can easily convert + constant handle to non-constant one by simple assignment: <code class="computeroutput"><span class="keyword">void</span> + <span class="identifier">foo</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> + <span class="special">{</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">nc</span> <span class="special">=</span> <span class="identifier">n</span><span class="special">;</span> <span class="special">}</span></code>, so const-correctness + here mainly provides additional documentation. + </p> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.modify.nodedata"></a><a class="link" href="modify.html#manual.modify.nodedata" title="Setting node data"> Setting node data</a> +</h3></div></div></div> +<a name="xml_node::set_name"></a><a name="xml_node::set_value"></a><p> + As discussed before, nodes can have name and value, both of which are strings. + Depending on node type, name or value may be absent. <code class="computeroutput"><span class="identifier">node_document</span></code> + nodes do not have name or value, <code class="computeroutput"><span class="identifier">node_element</span></code> + and <code class="computeroutput"><span class="identifier">node_declaration</span></code> nodes + always have a name but never have a value, <code class="computeroutput"><span class="identifier">node_pcdata</span></code>, + <code class="computeroutput"><span class="identifier">node_cdata</span></code> and <code class="computeroutput"><span class="identifier">node_comment</span></code> nodes never have a name but + always have a value (it may be empty though), <code class="computeroutput"><span class="identifier">node_pi</span></code> + nodes always have a name and a value (again, value may be empty). In order + to set node's name or value, you can use the following functions: + </p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">set_name</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">set_value</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">rhs</span><span class="special">);</span> +</pre> +<p> + Both functions try to set the name/value to the specified string, and return + the operation result. The operation fails if the node can not have name or + value (for instance, when trying to call <code class="computeroutput"><span class="identifier">set_name</span></code> + on a <code class="computeroutput"><span class="identifier">node_pcdata</span></code> node), if + the node handle is null, or if there is insufficient memory to handle the + request. The provided string is copied into document managed memory and can + be destroyed after the function returns (for example, you can safely pass + stack-allocated buffers to these functions). The name/value content is not + verified, so take care to use only valid XML names, or the document may become + malformed. + </p> +<p> + There is no equivalent of <code class="computeroutput"><span class="identifier">child_value</span></code> + function for modifying text children of the node. + </p> +<p> + This is an example of setting node name and value (<a href="../samples/modify_base.cpp" target="_top">samples/modify_base.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">node</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"node"</span><span class="special">);</span> + +<span class="comment">// change node name +</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">set_name</span><span class="special">(</span><span class="string">"notnode"</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">", new node name: "</span> <span class="special"><<</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">name</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + +<span class="comment">// change comment text +</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">last_child</span><span class="special">().</span><span class="identifier">set_value</span><span class="special">(</span><span class="string">"useless comment"</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">", new comment text: "</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">last_child</span><span class="special">().</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + +<span class="comment">// we can't change value of the element or name of the comment +</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">set_value</span><span class="special">(</span><span class="string">"1"</span><span class="special">)</span> <span class="special"><<</span> <span class="string">", "</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">last_child</span><span class="special">().</span><span class="identifier">set_name</span><span class="special">(</span><span class="string">"2"</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.modify.attrdata"></a><a class="link" href="modify.html#manual.modify.attrdata" title="Setting attribute data"> Setting attribute data</a> +</h3></div></div></div> +<a name="xml_attribute::set_name"></a><a name="xml_attribute::set_value"></a><p> + All attributes have name and value, both of which are strings (value may + be empty). You can set them with the following functions: + </p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="identifier">set_name</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="identifier">set_value</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">rhs</span><span class="special">);</span> +</pre> +<p> + Both functions try to set the name/value to the specified string, and return + the operation result. The operation fails if the attribute handle is null, + or if there is insufficient memory to handle the request. The provided string + is copied into document managed memory and can be destroyed after the function + returns (for example, you can safely pass stack-allocated buffers to these + functions). The name/value content is not verified, so take care to use only + valid XML names, or the document may become malformed. + </p> +<p> + In addition to string functions, several functions are provided for handling + attributes with numbers and booleans as values: + </p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="identifier">set_value</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="identifier">set_value</span><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="identifier">set_value</span><span class="special">(</span><span class="keyword">double</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="identifier">set_value</span><span class="special">(</span><span class="keyword">bool</span> <span class="identifier">rhs</span><span class="special">);</span> +</pre> +<p> + The above functions convert the argument to string and then call the base + <code class="computeroutput"><span class="identifier">set_value</span></code> function. Integers + are converted to a decimal form, floating-point numbers are converted to + either decimal or scientific form, depending on the number magnitude, boolean + values are converted to either <code class="computeroutput"><span class="string">"true"</span></code> + or <code class="computeroutput"><span class="string">"false"</span></code>. + </p> +<div class="caution"><table border="0" summary="Caution"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../images/caution.png"></td> +<th align="left">Caution</th> +</tr> +<tr><td align="left" valign="top"><p> + Number conversion functions depend on current C locale as set with <code class="computeroutput"><span class="identifier">setlocale</span></code>, so may generate unexpected + results if the locale is different from <code class="computeroutput"><span class="string">"C"</span></code>. + </p></td></tr> +</table></div> +<div class="note"><table border="0" summary="Note"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td> +<th align="left">Note</th> +</tr> +<tr><td align="left" valign="top"><p> + There are no portable 64-bit types in C++, so there is no corresponding + <code class="computeroutput"><span class="identifier">set_value</span></code> function. If + your platform has a 64-bit integer, you can easily write such a function + yourself. + </p></td></tr> +</table></div> +<a name="xml_attribute::assign"></a><p> + For convenience, all <code class="computeroutput"><span class="identifier">set_value</span></code> + functions have the corresponding assignment operators: + </p> +<pre class="programlisting"><span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span><span class="keyword">int</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span><span class="keyword">double</span> <span class="identifier">rhs</span><span class="special">);</span> +<span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">xml_attribute</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span><span class="keyword">bool</span> <span class="identifier">rhs</span><span class="special">);</span> +</pre> +<p> + These operators simply call the right <code class="computeroutput"><span class="identifier">set_value</span></code> + function and return the attribute they're called on; the return value of + <code class="computeroutput"><span class="identifier">set_value</span></code> is ignored, so + errors are not detected. + </p> +<p> + This is an example of setting attribute name and value (<a href="../samples/modify_base.cpp" target="_top">samples/modify_base.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_attribute</span> <span class="identifier">attr</span> <span class="special">=</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"id"</span><span class="special">);</span> + +<span class="comment">// change attribute name/value +</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">.</span><span class="identifier">set_name</span><span class="special">(</span><span class="string">"key"</span><span class="special">)</span> <span class="special"><<</span> <span class="string">", "</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">.</span><span class="identifier">set_value</span><span class="special">(</span><span class="string">"345"</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">", new attribute: "</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">.</span><span class="identifier">name</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"="</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">.</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + +<span class="comment">// we can use numbers or booleans +</span><span class="identifier">attr</span><span class="special">.</span><span class="identifier">set_value</span><span class="special">(</span><span class="number">1.234</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"new attribute value: "</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">.</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + +<span class="comment">// we can also use assignment operators for more concise code +</span><span class="identifier">attr</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"final attribute value: "</span> <span class="special"><<</span> <span class="identifier">attr</span><span class="special">.</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.modify.add"></a><a class="link" href="modify.html#manual.modify.add" title="Adding nodes/attributes"> Adding nodes/attributes</a> +</h3></div></div></div> +<a name="xml_node::append_attribute"></a><a name="xml_node::insert_attribute_after"></a><a name="xml_node::insert_attribute_before"></a><a name="xml_node::append_child"></a><a name="xml_node::insert_child_after"></a><a name="xml_node::insert_child_before"></a><p> + Nodes and attributes do not exist outside of document tree, so you can't + create them without adding them to some document. A node or attribute can + be created at the end of node/attribute list or before/after some other node: + </p> +<pre class="programlisting"><span class="identifier">xml_attribute</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">append_attribute</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">name</span><span class="special">);</span> +<span class="identifier">xml_attribute</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_attribute_after</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">name</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">attr</span><span class="special">);</span> +<span class="identifier">xml_attribute</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_attribute_before</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">name</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">attr</span><span class="special">);</span> + +<span class="identifier">xml_node</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">append_child</span><span class="special">(</span><span class="identifier">xml_node_type</span> <span class="identifier">type</span> <span class="special">=</span> <span class="identifier">node_element</span><span class="special">);</span> +<span class="identifier">xml_node</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_child_after</span><span class="special">(</span><span class="identifier">xml_node_type</span> <span class="identifier">type</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">node</span><span class="special">);</span> +<span class="identifier">xml_node</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_child_before</span><span class="special">(</span><span class="identifier">xml_node_type</span> <span class="identifier">type</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">node</span><span class="special">);</span> +</pre> +<p> + <code class="computeroutput"><span class="identifier">append_attribute</span></code> and <code class="computeroutput"><span class="identifier">append_child</span></code> create a new node/attribute + at the end of the corresponding list of the node the method is called on; + <code class="computeroutput"><span class="identifier">insert_attribute_after</span></code>, + <code class="computeroutput"><span class="identifier">insert_attribute_before</span></code>, + <code class="computeroutput"><span class="identifier">insert_child_after</span></code> and <code class="computeroutput"><span class="identifier">insert_attribute_before</span></code> add the node/attribute + before or after specified node/attribute. + </p> +<p> + Attribute functions create an attribute with the specified name; you can + specify the empty name and change the name later if you want to. Node functions + create the node with the specified type; since node type can't be changed, + you have to know the desired type beforehand. Also note that not all types + can be added as children; see below for clarification. + </p> +<p> + All functions return the handle to newly created object on success, and null + handle on failure. There are several reasons for failure: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + Adding fails if the target node is null; + </li> +<li class="listitem"> + Only <code class="computeroutput"><span class="identifier">node_element</span></code> nodes + can contain attributes, so attribute adding fails if node is not an element; + </li> +<li class="listitem"> + Only <code class="computeroutput"><span class="identifier">node_document</span></code> and + <code class="computeroutput"><span class="identifier">node_element</span></code> nodes can + contain children, so child node adding fails if target node is not an + element or a document; + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">node_document</span></code> and <code class="computeroutput"><span class="identifier">node_null</span></code> nodes can not be inserted + as children, so passing <code class="computeroutput"><span class="identifier">node_document</span></code> + or <code class="computeroutput"><span class="identifier">node_null</span></code> value as + type results in operation failure; + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">node_declaration</span></code> nodes + can only be added as children of the document node; attempt to insert + declaration node as a child of an element node fails; + </li> +<li class="listitem"> + Adding node/attribute results in memory allocation, which may fail; + </li> +<li class="listitem"> + Insertion functions fail if the specified node or attribute is not in + the target node's children/attribute list. + </li> +</ul></div> +<p> + Even if the operation fails, the document remains in consistent state, but + the requested node/attribute is not added. + </p> +<div class="caution"><table border="0" summary="Caution"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../images/caution.png"></td> +<th align="left">Caution</th> +</tr> +<tr><td align="left" valign="top"><p> + attribute() and child() functions do not add attributes or nodes to the + tree, so code like <code class="computeroutput"><span class="identifier">node</span><span class="special">.</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"id"</span><span class="special">)</span> <span class="special">=</span> <span class="number">123</span><span class="special">;</span></code> will not do anything if <code class="computeroutput"><span class="identifier">node</span></code> does not have an attribute with + name <code class="computeroutput"><span class="string">"id"</span></code>. Make sure + you're operating with existing attributes/nodes by adding them if necessary. + </p></td></tr> +</table></div> +<p> + This is an example of adding new attributes/nodes to the document (<a href="../samples/modify_add.cpp" target="_top">samples/modify_add.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="comment">// add node with some name +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">node</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">append_child</span><span class="special">();</span> +<span class="identifier">node</span><span class="special">.</span><span class="identifier">set_name</span><span class="special">(</span><span class="string">"node"</span><span class="special">);</span> + +<span class="comment">// add description node with text child +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">descr</span> <span class="special">=</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">append_child</span><span class="special">();</span> +<span class="identifier">descr</span><span class="special">.</span><span class="identifier">set_name</span><span class="special">(</span><span class="string">"description"</span><span class="special">);</span> +<span class="identifier">descr</span><span class="special">.</span><span class="identifier">append_child</span><span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">node_pcdata</span><span class="special">).</span><span class="identifier">set_value</span><span class="special">(</span><span class="string">"Simple node"</span><span class="special">);</span> + +<span class="comment">// add param node before the description +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">param</span> <span class="special">=</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">insert_child_before</span><span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">node_element</span><span class="special">,</span> <span class="identifier">descr</span><span class="special">);</span> +<span class="identifier">param</span><span class="special">.</span><span class="identifier">set_name</span><span class="special">(</span><span class="string">"param"</span><span class="special">);</span> + +<span class="comment">// add attributes to param node +</span><span class="identifier">param</span><span class="special">.</span><span class="identifier">append_attribute</span><span class="special">(</span><span class="string">"name"</span><span class="special">)</span> <span class="special">=</span> <span class="string">"version"</span><span class="special">;</span> +<span class="identifier">param</span><span class="special">.</span><span class="identifier">append_attribute</span><span class="special">(</span><span class="string">"value"</span><span class="special">)</span> <span class="special">=</span> <span class="number">1.1</span><span class="special">;</span> +<span class="identifier">param</span><span class="special">.</span><span class="identifier">insert_attribute_after</span><span class="special">(</span><span class="string">"type"</span><span class="special">,</span> <span class="identifier">param</span><span class="special">.</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"name"</span><span class="special">))</span> <span class="special">=</span> <span class="string">"float"</span><span class="special">;</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.modify.remove"></a><a class="link" href="modify.html#manual.modify.remove" title="Removing nodes/attributes"> Removing nodes/attributes</a> +</h3></div></div></div> +<a name="xml_node::remove_attribute"></a><a name="xml_node::remove_child"></a><p> + If you do not want your document to contain some node or attribute, you can + remove it with one of the following functions: + </p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">remove_attribute</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">a</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">remove_child</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">);</span> +</pre> +<p> + <code class="computeroutput"><span class="identifier">remove_attribute</span></code> removes + the attribute from the attribute list of the node, and returns the operation + result. <code class="computeroutput"><span class="identifier">remove_child</span></code> removes + the child node with the entire subtree (including all descendant nodes and + attributes) from the document, and returns the operation result. Removing + fails if one of the following is true: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + The node the function is called on is null; + </li> +<li class="listitem"> + The attribute/node to be removed is null; + </li> +<li class="listitem"> + The attribute/node to be removed is not in the node's attribute/child + list. + </li> +</ul></div> +<p> + Removing the attribute or node invalidates all handles to the same underlying + object, and also invalidates all iterators pointing to the same object. Removing + node also invalidates all past-the-end iterators to its attribute or child + node list. Be careful to ensure that all such handles and iterators either + do not exist or are not used after the attribute/node is removed. + </p> +<p> + If you want to remove the attribute or child node by its name, two additional + helper functions are available: + </p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">remove_attribute</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">name</span><span class="special">);</span> +<span class="keyword">bool</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">remove_child</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">name</span><span class="special">);</span> +</pre> +<p> + These functions look for the first attribute or child with the specified + name, and then remove it, returning the result. If there is no attribute + or child with such name, the function returns <code class="computeroutput"><span class="keyword">false</span></code>; + if there are two nodes with the given name, only the first node is deleted. + If you want to delete all nodes with the specified name, you can use code + like this: <code class="computeroutput"><span class="keyword">while</span> <span class="special">(</span><span class="identifier">node</span><span class="special">.</span><span class="identifier">remove_child</span><span class="special">(</span><span class="string">"tool"</span><span class="special">))</span> <span class="special">;</span></code>. + </p> +<p> + This is an example of removing attributes/nodes from the document (<a href="../samples/modify_remove.cpp" target="_top">samples/modify_remove.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="comment">// remove description node with the whole subtree +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">node</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"node"</span><span class="special">);</span> +<span class="identifier">node</span><span class="special">.</span><span class="identifier">remove_child</span><span class="special">(</span><span class="string">"description"</span><span class="special">);</span> + +<span class="comment">// remove id attribute +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">param</span> <span class="special">=</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"param"</span><span class="special">);</span> +<span class="identifier">param</span><span class="special">.</span><span class="identifier">remove_attribute</span><span class="special">(</span><span class="string">"value"</span><span class="special">);</span> + +<span class="comment">// we can also remove nodes/attributes by handles +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_attribute</span> <span class="identifier">id</span> <span class="special">=</span> <span class="identifier">param</span><span class="special">.</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"name"</span><span class="special">);</span> +<span class="identifier">param</span><span class="special">.</span><span class="identifier">remove_attribute</span><span class="special">(</span><span class="identifier">id</span><span class="special">);</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.modify.clone"></a><a class="link" href="modify.html#manual.modify.clone" title="Cloning nodes/attributes"> Cloning nodes/attributes</a> +</h3></div></div></div> +<a name="xml_node::append_copy"></a><a name="xml_node::insert_copy_after"></a><a name="xml_node::insert_copy_before"></a><p> + With the help of previously described functions, it is possible to create + trees with any contents and structure, including cloning the existing data. + However since this is an often needed operation, pugixml provides built-in + node/attribute cloning facilities. Since nodes and attributes do not exist + outside of document tree, you can't create a standalone copy - you have to + immediately insert it somewhere in the tree. For this, you can use one of + the following functions: + </p> +<pre class="programlisting"><span class="identifier">xml_attribute</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">append_copy</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">proto</span><span class="special">);</span> +<span class="identifier">xml_attribute</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_copy_after</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">proto</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">attr</span><span class="special">);</span> +<span class="identifier">xml_attribute</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_copy_before</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">proto</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_attribute</span><span class="special">&</span> <span class="identifier">attr</span><span class="special">);</span> +<span class="identifier">xml_node</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">append_copy</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">proto</span><span class="special">);</span> +<span class="identifier">xml_node</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_copy_after</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">proto</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">node</span><span class="special">);</span> +<span class="identifier">xml_node</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">insert_copy_before</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">proto</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">node</span><span class="special">);</span> +</pre> +<p> + These functions mirror the structure of <code class="computeroutput"><span class="identifier">append_child</span></code>, + <code class="computeroutput"><span class="identifier">insert_child_before</span></code> and related + functions - they take the handle to the prototype object, which is to be + cloned, insert a new attribute/node at the appropriate place, and then copy + the attribute data or the whole node subtree to the new object. The functions + return the handle to the resulting duplicate object, or null handle on failure. + </p> +<p> + The attribute is copied along with the name and value; the node is copied + along with its type, name and value; additionally attribute list and all + children are recursively cloned, resulting in the deep subtree clone. The + prototype object can be a part of the same document, or a part of any other + document. + </p> +<p> + The failure conditions resemble those of <code class="computeroutput"><span class="identifier">append_child</span></code>, + <code class="computeroutput"><span class="identifier">insert_child_before</span></code> and related + functions, <a class="link" href="modify.html#xml_node::append_child">consult their documentation + for more information</a>. There are additional caveats specific to cloning + functions: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + Cloning null handles results in operation failure; + </li> +<li class="listitem"> + Node cloning starts with insertion of the node of the same type as that + of the prototype; for this reason, cloning functions can not be directly + used to clone entire documents, since <code class="computeroutput"><span class="identifier">node_document</span></code> + is not a valid insertion type. The example below provides a workaround. + </li> +<li class="listitem"> + It is possible to copy a subtree as a child of some node inside this + subtree, i.e. <code class="computeroutput"><span class="identifier">node</span><span class="special">.</span><span class="identifier">append_copy</span><span class="special">(</span><span class="identifier">node</span><span class="special">.</span><span class="identifier">parent</span><span class="special">().</span><span class="identifier">parent</span><span class="special">());</span></code>. + This is a valid operation, and it results in a clone of the subtree in + the state before cloning started, i.e. no infinite recursion takes place. + </li> +</ul></div> +<p> + This is an example with one possible implementation of include tags in XML + (<a href="../samples/include.cpp" target="_top">samples/include.cpp</a>). It illustrates + node cloning and usage of other document modification functions: + </p> +<p> + +</p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">load_preprocess</span><span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_document</span><span class="special">&</span> <span class="identifier">doc</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">path</span><span class="special">);</span> + +<span class="keyword">bool</span> <span class="identifier">preprocess</span><span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">node</span><span class="special">)</span> +<span class="special">{</span> + <span class="keyword">for</span> <span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">child</span> <span class="special">=</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">first_child</span><span class="special">();</span> <span class="identifier">child</span><span class="special">;</span> <span class="special">)</span> + <span class="special">{</span> + <span class="keyword">if</span> <span class="special">(</span><span class="identifier">child</span><span class="special">.</span><span class="identifier">type</span><span class="special">()</span> <span class="special">==</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">node_pi</span> <span class="special">&&</span> <span class="identifier">strcmp</span><span class="special">(</span><span class="identifier">child</span><span class="special">.</span><span class="identifier">name</span><span class="special">(),</span> <span class="string">"include"</span><span class="special">)</span> <span class="special">==</span> <span class="number">0</span><span class="special">)</span> + <span class="special">{</span> + <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">include</span> <span class="special">=</span> <span class="identifier">child</span><span class="special">;</span> + + <span class="comment">// load new preprocessed document (note: ideally this should handle relative paths) +</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">path</span> <span class="special">=</span> <span class="identifier">include</span><span class="special">.</span><span class="identifier">value</span><span class="special">();</span> + + <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_document</span> <span class="identifier">doc</span><span class="special">;</span> + <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">load_preprocess</span><span class="special">(</span><span class="identifier">doc</span><span class="special">,</span> <span class="identifier">path</span><span class="special">))</span> <span class="keyword">return</span> <span class="keyword">false</span><span class="special">;</span> + + <span class="comment">// insert the comment marker above include directive +</span> <span class="identifier">node</span><span class="special">.</span><span class="identifier">insert_child_before</span><span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">node_comment</span><span class="special">,</span> <span class="identifier">include</span><span class="special">).</span><span class="identifier">set_value</span><span class="special">(</span><span class="identifier">path</span><span class="special">);</span> + + <span class="comment">// copy the document above the include directive (this retains the original order!) +</span> <span class="keyword">for</span> <span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_node</span> <span class="identifier">ic</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">first_child</span><span class="special">();</span> <span class="identifier">ic</span><span class="special">;</span> <span class="identifier">ic</span> <span class="special">=</span> <span class="identifier">ic</span><span class="special">.</span><span class="identifier">next_sibling</span><span class="special">())</span> + <span class="special">{</span> + <span class="identifier">node</span><span class="special">.</span><span class="identifier">insert_copy_before</span><span class="special">(</span><span class="identifier">ic</span><span class="special">,</span> <span class="identifier">include</span><span class="special">);</span> + <span class="special">}</span> + + <span class="comment">// remove the include node and move to the next child +</span> <span class="identifier">child</span> <span class="special">=</span> <span class="identifier">child</span><span class="special">.</span><span class="identifier">next_sibling</span><span class="special">();</span> + + <span class="identifier">node</span><span class="special">.</span><span class="identifier">remove_child</span><span class="special">(</span><span class="identifier">include</span><span class="special">);</span> + <span class="special">}</span> + <span class="keyword">else</span> + <span class="special">{</span> + <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">preprocess</span><span class="special">(</span><span class="identifier">child</span><span class="special">))</span> <span class="keyword">return</span> <span class="keyword">false</span><span class="special">;</span> + + <span class="identifier">child</span> <span class="special">=</span> <span class="identifier">child</span><span class="special">.</span><span class="identifier">next_sibling</span><span class="special">();</span> + <span class="special">}</span> + <span class="special">}</span> + + <span class="keyword">return</span> <span class="keyword">true</span><span class="special">;</span> +<span class="special">}</span> + +<span class="keyword">bool</span> <span class="identifier">load_preprocess</span><span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_document</span><span class="special">&</span> <span class="identifier">doc</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">path</span><span class="special">)</span> +<span class="special">{</span> + <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load_file</span><span class="special">(</span><span class="identifier">path</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_default</span> <span class="special">|</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_pi</span><span class="special">);</span> <span class="comment">// for <?include?> +</span> + <span class="keyword">return</span> <span class="identifier">result</span> <span class="special">?</span> <span class="identifier">preprocess</span><span class="special">(</span><span class="identifier">doc</span><span class="special">)</span> <span class="special">:</span> <span class="keyword">false</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +</div> +</div> +<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> +<td align="left"></td> +<td align="right"><div class="copyright-footer">Copyright © 2010 Arseny Kapoulkine<p> + Distributed under the MIT License + </p> +</div></td> +</tr></table> +<hr> +<table width="100%"><tr> +<td>pugixml 0.9 manual | + <a href="../manual.html">Overview</a> | + <a href="install.html">Installation</a> | + Document: + <a href="dom.html">Object model</a> · <a href="loading.html">Loading</a> · <a href="access.html">Accessing</a> · <b>Modifying</b> · <a href="saving.html">Saving</a> | + <a href="xpath.html">XPath</a> | + <a href="apiref.html">API Reference</a> | + <a href="toc.html">Table of Contents</a> +</td> +<td width="*" align="right"><div class="spirit-nav"> +<a accesskey="p" href="access.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../manual.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../manual.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="saving.html"><img src="../images/next.png" alt="Next"></a> +</div></td> +</tr></table> +</body> +</html> |