wxWidgets/interface/xml/xml.h

/////////////////////////////////////////////////////////////////////////////
// Name:        xml/xml.h
// Purpose:     documentation for wxXmlNode class
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

/**
    @class wxXmlNode
    @headerfile xml.h wx/xml/xml.h

    Represents a node in an XML document. See wxXmlDocument.

    Node has a name and may have content and attributes. Most common node types are
    @c wxXML_TEXT_NODE (name and attributes are irrelevant) and
    @c wxXML_ELEMENT_NODE (e.g. in @c titlehi/title there is an element
    with name="title", irrelevant content and one child (@c wxXML_TEXT_NODE
    with content="hi").

    If @c wxUSE_UNICODE is 0, all strings are encoded in the encoding given to
    wxXmlDocument::Load (default is UTF-8).

    @library{wxxml}
    @category{xml}

    @seealso
    wxXmlDocument, wxXmlAttribute
*/
class wxXmlNode
{
public:
    //@{
    /**
        A simplified version of the first constructor form, assuming a @NULL parent.
    */
    wxXmlNode(wxXmlNode* parent, wxXmlNodeType type,
              const wxString& name,
              const wxString& content = wxEmptyString,
              wxXmlAttribute* attrs = @NULL,
              wxXmlNode* next = @NULL, int lineNo = -1);
    wxXmlNode(const wxXmlNode& node);
    wxXmlNode(wxXmlNodeType type, const wxString& name,
              const wxString& content = wxEmptyString,
              int lineNo = -1);
    //@}

    /**
        The virtual destructor. Deletes attached children and attributes.
    */
    ~wxXmlNode();

    //@{
    /**
        Appends given attribute to the list of attributes for this node.
    */
    void AddAttribute(const wxString& name, const wxString& value);
    void AddAttribute(wxXmlAttribute* attr);
    //@}

    /**
        Adds the given node as child of this node. To attach a second children to this
        node, use the
        SetNext() function of the @e child node.
    */
    void AddChild(wxXmlNode* child);

    /**
        Removes the first attributes which has the given @e name from the list of
        attributes for this node.
    */
    bool DeleteAttribute(const wxString& name);

    //@{
    /**
        Returns the value of the attribute named @e attrName if it does exist.
        If it does not exist, the @e defaultVal is returned.
    */
    bool GetAttribute(const wxString& attrName, wxString* value);
    wxString GetAttribute(const wxString& attrName,
                          const wxString& defaultVal);
    //@}

    /**
        Return a pointer to the first attribute of this node.
    */
    wxXmlAttribute * GetAttributes();

    /**
        Returns the first child of this node.
        To get a pointer to the second child of this node (if it does exist), use the
        GetNext() function on the returned value.
    */
    wxXmlNode* GetChildren();

    /**
        Returns the content of this node. Can be an empty string.
        Be aware that for nodes of type @c wxXML_ELEMENT_NODE (the most used node type)
        the
        content is an empty string. See GetNodeContent() for more details.
    */
    wxString GetContent();

    /**
        Returns the number of nodes which separe this node from @c grandparent.
        
        This function searches only the parents of this node until it finds @c
        grandparent
        or the @NULL node (which is the parent of non-linked nodes or the parent of a
        wxXmlDocument's root node).
    */
    int GetDepth(wxXmlNode* grandparent = @NULL);

    /**
        Returns line number of the node in the input XML file or -1 if it is unknown.
    */
    int GetLineNumber();

    /**
        Returns the name of this node. Can be an empty string (e.g. for nodes of type
        @c wxXML_TEXT_NODE or @c wxXML_CDATA_SECTION_NODE).
    */
    wxString GetName();

    /**
        Returns a pointer to the sibling of this node or @NULL if there are no
        siblings.
    */
    wxXmlNode* GetNext();

    /**
        Returns the content of the first child node of type @c wxXML_TEXT_NODE or @c
        wxXML_CDATA_SECTION_NODE.
        This function is very useful since the XML snippet @c
        "tagnametagcontent/tagname" is represented by
        expat with the following tag tree:
        or eventually:
        An empty string is returned if the node has no children of type @c
        wxXML_TEXT_NODE or @c wxXML_CDATA_SECTION_NODE, or if the content of the first child of such types is empty.
    */
    wxString GetNodeContent();

    /**
        Returns a pointer to the parent of this node or @NULL if this node has no
        parent.
    */
    wxXmlNode* GetParent();

    /**
        Returns the type of this node.
    */
    wxXmlNodeType GetType();

    /**
        Returns @true if this node has a attribute named @e attrName.
    */
    bool HasAttribute(const wxString& attrName);

    /**
        Inserts the @e child node after @e before_node in the children list.
        If @e before_node is @NULL, then @e child is prepended to the list of
        children and
        becomes the first child of this node.
        Returns @true if @e before_node has been found and the @e child node has been
        inserted.
    */
    bool InsertChild(wxXmlNode* child, wxXmlNode* before_node);

    /**
        Returns @true if the content of this node is a string containing only
        whitespaces (spaces,
        tabs, new lines, etc). Note that this function is locale-independent since the
        parsing of XML
        documents must always produce the exact same tree regardless of the locale it
        runs under.
    */
    bool IsWhitespaceOnly();

    /**
        Removes the given node from the children list. Returns @true if the node was
        found and removed
        or @false if the node could not be found.
        
        Note that the caller is reponsible for deleting the removed node in order to
        avoid memory leaks.
    */
    bool RemoveChild(wxXmlNode* child);

    /**
        Sets as first attribute the given wxXmlAttribute object.
        The caller is responsible to delete any previously present attributes attached
        to this node.
    */
    void SetAttributes(wxXmlAttribute* attr);

    /**
        Sets as first child the given node. The caller is responsible to delete any
        previously present
        children node.
    */
    void SetChildren(wxXmlNode* child);

    /**
        Sets the content of this node.
    */
    void SetContent(const wxString& con);

    /**
        Sets the name of this node.
    */
    void SetName(const wxString& name);

    /**
        Sets as sibling the given node. The caller is responsible to delete any
        previously present
        sibling node.
    */
    void SetNext(wxXmlNode* next);

    /**
        Sets as parent the given node. The caller is responsible to delete any
        previously present
        parent node.
    */
    void SetParent(wxXmlNode* parent);

    /**
        Sets the type of this node.
    */
    void SetType(wxXmlNodeType type);

    /**
        See the copy constructor for more info.
    */
    wxXmlNode operator=(const wxXmlNode& node);
};


/**
    @class wxXmlAttribute
    @headerfile xml.h wx/xml/xml.h

    Represents a node attribute.

    Example: in @c img src="hello.gif" id="3"/, @c "src" is attribute with value
    @c "hello.gif" and @c "id" is a attribute with value @c "3".

    @library{wxxml}
    @category{xml}

    @seealso
    wxXmlDocument, wxXmlNode
*/
class wxXmlAttribute
{
public:
    //@{
    /**
        Creates the attribute with given @e name and @e value.
        If @e next is not @NULL, then sets it as sibling of this attribute.
    */
    wxXmlAttribute();
    wxXmlAttribute(const wxString& name, const wxString& value,
                   wxXmlAttribute* next = @NULL);
    //@}

    /**
        The virtual destructor.
    */
    ~wxXmlAttribute();

    /**
        Returns the name of this attribute.
    */
    wxString GetName();

    /**
        Returns the sibling of this attribute or @NULL if there are no siblings.
    */
    wxXmlAttribute* GetNext();

    /**
        Returns the value of this attribute.
    */
    wxString GetValue();

    /**
        Sets the name of this attribute.
    */
    void SetName(const wxString& name);

    /**
        Sets the sibling of this attribute.
    */
    void SetNext(wxXmlAttribute* next);

    /**
        Sets the value of this attribute.
    */
    void SetValue(const wxString& value);
};


/**
    @class wxXmlDocument
    @headerfile xml.h wx/xml/xml.h

    This class holds XML data/document as parsed by XML parser in the root node.

    wxXmlDocument internally uses the expat library which comes with wxWidgets to
    parse the given stream.

    A simple example of using XML classes is:

    @code
    wxXmlDocument doc;
    if (!doc.Load(wxT("myfile.xml")))
        return @false;

    // start processing the XML file
    if (doc.GetRoot()-GetName() != wxT("myroot-node"))
        return @false;

    wxXmlNode *child = doc.GetRoot()-GetChildren();
    while (child) {

        if (child-GetName() == wxT("tag1")) {

            // process text enclosed by tag1/tag1
            wxString content = child-GetNodeContent();

            ...

            // process attributes of tag1
            wxString attrvalue1 =
                child-GetAttribute(wxT("attr1"),
                                  wxT("default-value"));
            wxString attrvalue2 =
                child-GetAttribute(wxT("attr2"),
                                  wxT("default-value"));

            ...

        } else if (child-GetName() == wxT("tag2")) {

            // process tag2 ...
        }

        child = child-GetNext();
    }
    @endcode

    @b Note: if you want to preserve the original formatting of the loaded file
    including whitespaces
    and indentation, you need to turn off whitespace-only textnode removal and
    automatic indentation:

    @code
    wxXmlDocument doc;
    doc.Load(wxT("myfile.xml"), wxT("UTF-8"), wxXMLDOC_KEEP_WHITESPACE_NODES);

    // myfile2.xml will be indentic to myfile.xml saving it this way:
    doc.Save(wxT("myfile2.xml"), wxXML_NO_INDENTATION);
    @endcode

    Using default parameters, you will get a reformatted document which in general
    is different from
    the original loaded content:

    @code
    wxXmlDocument doc;
    doc.Load(wxT("myfile.xml"));
    doc.Save(wxT("myfile2.xml"));  // myfile2.xml != myfile.xml
    @endcode

    @library{wxxml}
    @category{xml}

    @seealso
    wxXmlNode, wxXmlAttribute
*/
class wxXmlDocument : public wxObject
{
public:
    //@{
    /**
        Copy constructor. Deep copies all the XML tree of the given document.
    */
    wxXmlDocument();
    wxXmlDocument(const wxString& filename);
    wxXmlDocument(wxInputStream& stream);
    wxXmlDocument(const wxXmlDocument& doc);
    //@}

    /**
        Virtual destructor. Frees the document root node.
    */
    ~wxXmlDocument();

    /**
        Detaches the document root node and returns it. The document root node will be
        set to @NULL
        and thus IsOk() will return @false after calling this function.
        
        Note that the caller is reponsible for deleting the returned node in order to
        avoid memory leaks.
    */
    wxXmlNode* DetachRoot();

    /**
        Returns encoding of in-memory representation of the document
        (same as passed to Load() or constructor, defaults to UTF-8).
        
        NB: this is meaningless in Unicode build where data are stored as @c wchar_t*.
    */
    wxString GetEncoding();

    /**
        Returns encoding of document (may be empty).
        
        Note: this is the encoding original file was saved in, @b not the
        encoding of in-memory representation!
    */
    wxString GetFileEncoding();

    /**
        Returns the root node of the document.
    */
    wxXmlNode* GetRoot();

    /**
        Returns the version of document.
        This is the value in the @c ?xml version="1.0"? header of the XML document.
        If the version attribute was not explicitely given in the header, this function
        returns an empty string.
    */
    wxString GetVersion();

    /**
        Returns @true if the document has been loaded successfully.
    */
#define bool IsOk()     /* implementation is private */

    //@{
    /**
        , @b int@e flags = wxXMLDOC_NONE)
        
        Like above but takes the data from given input stream.
    */
    bool Load(const wxString& filename);
    int bool Load(wxInputStream& stream);
    //@}

    //@{
    /**
        Saves XML tree in the given output stream. See other overload for a description
        of @c indentstep.
    */
    bool Save(const wxString& filename, int indentstep = 1);
    bool Save(wxOutputStream& stream, int indentstep = 1);
    //@}

    /**
        Sets the enconding of the document.
    */
    void SetEncoding(const wxString& enc);

    /**
        Sets the enconding of the file which will be used to save the document.
    */
    void SetFileEncoding(const wxString& encoding);

    /**
        Sets the root node of this document. Deletes previous root node.
        Use DetachRoot() and then
        SetRoot() if you want
        to replace the root node without deleting the old document tree.
    */
    void SetRoot(wxXmlNode* node);

    /**
        Sets the version of the XML file which will be used to save the document.
    */
    void SetVersion(const wxString& version);

    /**
        Deep copies the given document.
    */
    wxXmlDocument& operator operator=(const wxXmlDocument& doc);
};