interface/wx/xml/xml.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        xml/xml.h
   3 // Purpose:     interface of wxXmlNode, wxXmlAttribute, wxXmlDocument
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows licence
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9
  10 /// Represents XML node type.
  11 enum wxXmlNodeType
  12 {
  13     // note: values are synchronized with xmlElementType from libxml
  14     wxXML_ELEMENT_NODE       =  1,
  15     wxXML_ATTRIBUTE_NODE     =  2,
  16     wxXML_TEXT_NODE          =  3,
  17     wxXML_CDATA_SECTION_NODE =  4,
  18     wxXML_ENTITY_REF_NODE    =  5,
  19     wxXML_ENTITY_NODE        =  6,
  20     wxXML_PI_NODE            =  7,
  21     wxXML_COMMENT_NODE       =  8,
  22     wxXML_DOCUMENT_NODE      =  9,
  23     wxXML_DOCUMENT_TYPE_NODE = 10,
  24     wxXML_DOCUMENT_FRAG_NODE = 11,
  25     wxXML_NOTATION_NODE      = 12,
  26     wxXML_HTML_DOCUMENT_NODE = 13
  27 };
  28
  29 /**
  30     @class wxXmlNode
  31
  32     Represents a node in an XML document. See wxXmlDocument.
  33
  34     Node has a name and may have content and attributes.
  35
  36     Most common node types are @c wxXML_TEXT_NODE (name and attributes are irrelevant)
  37     and @c wxXML_ELEMENT_NODE.
  38
  39     Example: in <tt>\<title\>hi\</title\></tt> there is an element with the name
  40     @c title and irrelevant content and one child of type @c wxXML_TEXT_NODE
  41     with @c hi as content.
  42
  43     The @c wxXML_PI_NODE type sets the name to the PI target and the contents to
  44     the instructions. Note that whilst the PI instructions are often in the form
  45     of pseudo-attributes these do not use the nodes attribute system. It is the users
  46     responsibility to code and decode the instruction text.
  47
  48     If @c wxUSE_UNICODE is 0, all strings are encoded in the encoding given to
  49     wxXmlDocument::Load (default is UTF-8).
  50
  51     @library{wxxml}
  52     @category{xml}
  53
  54     @see wxXmlDocument, wxXmlAttribute
  55 */
  56 class wxXmlNode
  57 {
  58 public:
  59     /**
  60         Creates this XML node and eventually insert it into an existing XML tree.
  61
  62         @param parent
  63             The parent node to which append this node instance.
  64             If this argument is @NULL this new node will be floating and it can
  65             be appended later to another one using the AddChild() or InsertChild()
  66             functions. Otherwise the child is already added to the XML tree by
  67             this constructor and it shouldn't be done again.
  68         @param type
  69             One of the ::wxXmlNodeType enumeration value.
  70         @param name
  71             The name of the node. This is the string which appears between angular brackets.
  72         @param content
  73             The content of the node.
  74             Only meaningful when type is @c wxXML_TEXT_NODE or @c wxXML_CDATA_SECTION_NODE.
  75         @param attrs
  76             If not @NULL, this wxXmlAttribute object and its eventual siblings are attached to the node.
  77         @param next
  78             If not @NULL, this node and its eventual siblings are attached to the node.
  79         @param lineNo
  80             Number of line this node was present at in input file or -1.
  81     */
  82     wxXmlNode(wxXmlNode* parent, wxXmlNodeType type,
  83               const wxString& name,
  84               const wxString& content = wxEmptyString,
  85               wxXmlAttribute* attrs = NULL,
  86               wxXmlNode* next = NULL, int lineNo = -1);
  87
  88     /**
  89         A simplified version of the first constructor form, assuming a @NULL parent.
  90
  91         @param type
  92             One of the ::wxXmlNodeType enumeration value.
  93         @param name
  94             The name of the node. This is the string which appears between angular brackets.
  95         @param content
  96             The content of the node.
  97             Only meaningful when type is @c wxXML_TEXT_NODE or @c wxXML_CDATA_SECTION_NODE.
  98         @param lineNo
  99             Number of line this node was present at in input file or -1.
 100     */
 101     wxXmlNode(wxXmlNodeType type, const wxString& name,
 102               const wxString& content = wxEmptyString,
 103               int lineNo = -1);
 104
 105     /**
 106         Copy constructor.
 107
 108         Note that this does NOT copy siblings and parent pointer, i.e. GetParent()
 109         and GetNext() will return @NULL after using copy ctor and are never unmodified by operator=().
 110         On the other hand, it DOES copy children and attributes.
 111     */
 112     wxXmlNode(const wxXmlNode& node);
 113
 114     /**
 115         The virtual destructor. Deletes attached children and attributes.
 116     */
 117     virtual ~wxXmlNode();
 118
 119     /**
 120         Appends a attribute with given @a name and @a value to the list of
 121         attributes for this node.
 122     */
 123     virtual void AddAttribute(const wxString& name, const wxString& value);
 124
 125     /**
 126         Appends given attribute to the list of attributes for this node.
 127     */
 128     virtual void AddAttribute(wxXmlAttribute* attr);
 129
 130     /**
 131         Adds node @a child as the last child of this node.
 132
 133         @note
 134         Note that this function works in O(n) time where @e n is the number
 135         of existing children. Consequently, adding large number of child
 136         nodes using this method can be expensive, because it has O(n^2) time
 137         complexity in number of nodes to be added. Use InsertChildAfter() to
 138         populate XML tree in linear time.
 139
 140         @see InsertChild(), InsertChildAfter()
 141     */
 142     virtual void AddChild(wxXmlNode* child);
 143
 144     /**
 145         Removes the first attributes which has the given @a name from the list of
 146         attributes for this node.
 147     */
 148     virtual bool DeleteAttribute(const wxString& name);
 149
 150     /**
 151         Returns true if a attribute named attrName could be found.
 152         The value of that attribute is saved in value (which must not be @NULL).
 153     */
 154     bool GetAttribute(const wxString& attrName, wxString* value) const;
 155
 156     /**
 157         Returns the value of the attribute named @a attrName if it does exist.
 158         If it does not exist, the @a defaultVal is returned.
 159     */
 160     wxString GetAttribute(const wxString& attrName,
 161                           const wxString& defaultVal = wxEmptyString) const;
 162
 163     /**
 164         Return a pointer to the first attribute of this node.
 165     */
 166     wxXmlAttribute* GetAttributes() const;
 167
 168     /**
 169         Returns the first child of this node.
 170         To get a pointer to the second child of this node (if it does exist), use the
 171         GetNext() function on the returned value.
 172     */
 173     wxXmlNode* GetChildren() const;
 174
 175     /**
 176         Returns the content of this node. Can be an empty string.
 177         Be aware that for nodes of type @c wxXML_ELEMENT_NODE (the most used node type)
 178         the content is an empty string. See GetNodeContent() for more details.
 179     */
 180     const wxString& GetContent() const;
 181
 182     /**
 183         Returns the number of nodes which separate this node from @c grandparent.
 184
 185         This function searches only the parents of this node until it finds
 186         @a grandparent or the @NULL node (which is the parent of non-linked
 187         nodes or the parent of a wxXmlDocument's root element node).
 188     */
 189     int GetDepth(wxXmlNode* grandparent = NULL) const;
 190
 191     /**
 192         Returns a flag indicating whether encoding conversion is necessary when saving. The default is @false.
 193
 194         You can improve saving efficiency considerably by setting this value.
 195     */
 196     bool GetNoConversion() const;
 197
 198     /**
 199         Returns line number of the node in the input XML file or @c -1 if it is unknown.
 200     */
 201     int GetLineNumber() const;
 202
 203     /**
 204         Returns the name of this node.
 205         Can be an empty string (e.g. for nodes of type @c wxXML_TEXT_NODE or
 206         @c wxXML_CDATA_SECTION_NODE).
 207     */
 208     const wxString& GetName() const;
 209
 210     /**
 211         Returns a pointer to the sibling of this node or @NULL if there are no
 212         siblings.
 213     */
 214     wxXmlNode* GetNext() const;
 215
 216     /**
 217         Returns the content of the first child node of type @c wxXML_TEXT_NODE
 218         or @c wxXML_CDATA_SECTION_NODE.
 219         This function is very useful since the XML snippet @c "tagnametagcontent/tagname"
 220         is represented by expat with the following tag tree:
 221
 222         @code
 223         wxXML_ELEMENT_NODE name="tagname", content=""
 224         |-- wxXML_TEXT_NODE name="", content="tagcontent"
 225         @endcode
 226
 227         or eventually:
 228
 229         @code
 230         wxXML_ELEMENT_NODE name="tagname", content=""
 231         |-- wxXML_CDATA_SECTION_NODE name="", content="tagcontent"
 232         @endcode
 233
 234         An empty string is returned if the node has no children of type
 235         @c wxXML_TEXT_NODE or @c wxXML_CDATA_SECTION_NODE, or if the content
 236         of the first child of such types is empty.
 237     */
 238     wxString GetNodeContent() const;
 239
 240     /**
 241         Returns a pointer to the parent of this node or @NULL if this node has no
 242         parent.
 243     */
 244     wxXmlNode* GetParent() const;
 245
 246     /**
 247         Returns the type of this node.
 248     */
 249     wxXmlNodeType GetType() const;
 250
 251     /**
 252         Returns @true if this node has a attribute named @a attrName.
 253     */
 254     bool HasAttribute(const wxString& attrName) const;
 255
 256     /**
 257         Inserts the @a child node immediately before @a followingNode in the
 258         children list.
 259
 260         @return @true if @a followingNode has been found and the @a child
 261                 node has been inserted.
 262
 263         @note
 264         For historical reasons, @a followingNode may be @NULL. In that case,
 265         then @a child is prepended to the list of children and becomes the
 266         first child of this node, i.e. it behaves identically to using the
 267         first children (as returned by GetChildren()) for @a followingNode).
 268
 269         @see AddChild(), InsertChildAfter()
 270     */
 271     virtual bool InsertChild(wxXmlNode* child, wxXmlNode* followingNode);
 272
 273     /**
 274         Inserts the @a child node immediately after @a precedingNode in the
 275         children list.
 276
 277         @return @true if @a precedingNode has been found and the @a child
 278                 node has been inserted.
 279
 280         @param child
 281             The child to insert.
 282         @param precedingNode
 283             The node to insert @a child after. As a special case, this can be
 284             @NULL if this node has no children yet -- in that case, @a child
 285             will become this node's only child node.
 286
 287         @since 2.8.8
 288
 289         @see InsertChild(), AddChild()
 290     */
 291     virtual bool InsertChildAfter(wxXmlNode* child, wxXmlNode* precedingNode);
 292
 293     /**
 294         Returns @true if the content of this node is a string containing only
 295         whitespaces (spaces, tabs, new lines, etc).
 296
 297         Note that this function is locale-independent since the parsing of XML
 298         documents must always produce the exact same tree regardless of the
 299         locale it runs under.
 300     */
 301     bool IsWhitespaceOnly() const;
 302
 303     /**
 304         Removes the given node from the children list.
 305
 306         Returns @true if the node was found and removed or @false if the node
 307         could not be found.
 308         Note that the caller is responsible for deleting the removed node in order
 309         to avoid memory leaks.
 310     */
 311     virtual bool RemoveChild(wxXmlNode* child);
 312
 313     /**
 314         Sets as first attribute the given wxXmlAttribute object.
 315
 316         The caller is responsible for deleting any previously present attributes
 317         attached to this node.
 318     */
 319     void SetAttributes(wxXmlAttribute* attr);
 320
 321     /**
 322         Sets as first child the given node.
 323
 324         The caller is responsible for deleting any previously present children node.
 325     */
 326     void SetChildren(wxXmlNode* child);
 327
 328     /**
 329         Sets the content of this node.
 330     */
 331     void SetContent(const wxString& con);
 332
 333     /**
 334         Sets the name of this node.
 335     */
 336     void SetName(const wxString& name);
 337
 338     /**
 339         Sets as sibling the given node.
 340
 341         The caller is responsible for deleting any previously present sibling node.
 342     */
 343     void SetNext(wxXmlNode* next);
 344
 345     /**
 346         Sets a flag to indicate whether encoding conversion is necessary when saving. The default is @false.
 347
 348         You can improve saving efficiency considerably by setting this value.
 349     */
 350     void SetNoConversion(bool noconversion);
 351
 352     /**
 353         Sets as parent the given node.
 354
 355         The caller is responsible for deleting any previously present parent node.
 356     */
 357     void SetParent(wxXmlNode* parent);
 358
 359     /**
 360         Sets the type of this node.
 361     */
 362     void SetType(wxXmlNodeType type);
 363
 364     /**
 365         See the copy constructor for more info.
 366     */
 367     wxXmlNode& operator=(const wxXmlNode& node);
 368 };
 369
 370
 371
 372 /**
 373     @class wxXmlAttribute
 374
 375     Represents a node attribute.
 376
 377     Example: in <tt>\<img src="hello.gif" id="3"/\></tt>, @c src is an attribute
 378     with value @c hello.gif and @c id is an attribute with value @c 3.
 379
 380     @library{wxxml}
 381     @category{xml}
 382
 383     @see wxXmlDocument, wxXmlNode
 384 */
 385 class wxXmlAttribute
 386 {
 387 public:
 388     /**
 389         Default constructor.
 390     */
 391     wxXmlAttribute();
 392
 393     /**
 394         Creates the attribute with given @a name and @a value.
 395         If @a next is not @NULL, then sets it as sibling of this attribute.
 396     */
 397     wxXmlAttribute(const wxString& name, const wxString& value,
 398                    wxXmlAttribute* next = NULL);
 399
 400     /**
 401         The virtual destructor.
 402     */
 403     virtual ~wxXmlAttribute();
 404
 405     /**
 406         Returns the name of this attribute.
 407     */
 408     wxString GetName() const;
 409
 410     /**
 411         Returns the sibling of this attribute or @NULL if there are no siblings.
 412     */
 413     wxXmlAttribute* GetNext() const;
 414
 415     /**
 416         Returns the value of this attribute.
 417     */
 418     wxString GetValue() const;
 419
 420     /**
 421         Sets the name of this attribute.
 422     */
 423     void SetName(const wxString& name);
 424
 425     /**
 426         Sets the sibling of this attribute.
 427     */
 428     void SetNext(wxXmlAttribute* next);
 429
 430     /**
 431         Sets the value of this attribute.
 432     */
 433     void SetValue(const wxString& value);
 434 };
 435
 436
 437
 438 /**
 439     @class wxXmlDocument
 440
 441     This class holds XML data/document as parsed by XML parser in the root node.
 442
 443     wxXmlDocument internally uses the expat library which comes with wxWidgets to
 444     parse the given stream.
 445
 446     A simple example of using XML classes is:
 447
 448     @code
 449     wxXmlDocument doc;
 450     if (!doc.Load("myfile.xml"))
 451         return false;
 452
 453     // start processing the XML file
 454     if (doc.GetRoot()->GetName() != "myroot-node")
 455         return false;
 456
 457     // examine prologue
 458     wxXmlNode *prolog = doc.GetDocumentNode()->GetChildren();
 459     while (prolog) {
 460
 461         if (prolog->GetType() == wxXML_PI_NODE && prolog->GetName() == "target") {
 462
 463             // process Process Instruction contents
 464             wxString pi = prolog->GetContent();
 465
 466             ...
 467
 468         }
 469     }
 470
 471     wxXmlNode *child = doc.GetRoot()->GetChildren();
 472     while (child) {
 473
 474         if (child->GetName() == "tag1") {
 475
 476             // process text enclosed by tag1/tag1
 477             wxString content = child->GetNodeContent();
 478
 479             ...
 480
 481             // process attributes of tag1
 482             wxString attrvalue1 =
 483                 child->GetAttribute("attr1", "default-value");
 484             wxString attrvalue2 =
 485                 child->GetAttribute("attr2", "default-value");
 486
 487             ...
 488
 489         } else if (child->GetName() == "tag2") {
 490
 491             // process tag2 ...
 492         }
 493
 494         child = child->GetNext();
 495     }
 496     @endcode
 497
 498     Note that if you want to preserve the original formatting of the loaded file
 499     including whitespaces and indentation, you need to turn off whitespace-only
 500     textnode removal and automatic indentation:
 501
 502     @code
 503     wxXmlDocument doc;
 504     doc.Load("myfile.xml", "UTF-8", wxXMLDOC_KEEP_WHITESPACE_NODES);
 505
 506     // myfile2.xml will be identical to myfile.xml saving it this way:
 507     doc.Save("myfile2.xml", wxXML_NO_INDENTATION);
 508     @endcode
 509
 510     Using default parameters, you will get a reformatted document which in general
 511     is different from the original loaded content:
 512
 513     @code
 514     wxXmlDocument doc;
 515     doc.Load("myfile.xml");
 516     doc.Save("myfile2.xml");  // myfile2.xml != myfile.xml
 517     @endcode
 518
 519     @library{wxxml}
 520     @category{xml}
 521
 522     @see wxXmlNode, wxXmlAttribute
 523 */
 524 class wxXmlDocument : public wxObject
 525 {
 526 public:
 527     /**
 528         Default constructor.
 529     */
 530     wxXmlDocument();
 531
 532     /**
 533         Copy constructor. Deep copies all the XML tree of the given document.
 534     */
 535     wxXmlDocument(const wxXmlDocument& doc);
 536
 537     /**
 538         Loads the given filename using the given encoding. See Load().
 539     */
 540     wxXmlDocument(const wxString& filename,
 541                   const wxString& encoding = "UTF-8"));
 542
 543     /**
 544         Loads the XML document from given stream using the given encoding. See Load().
 545     */
 546     wxXmlDocument(wxInputStream& stream,
 547                   const wxString& encoding = "UTF-8");
 548
 549     /**
 550         Virtual destructor. Frees the document root node.
 551     */
 552     virtual ~wxXmlDocument();
 553
 554     /**
 555         Appends a Process Instruction or Comment node to the document prologue.
 556
 557         Calling this function will create a prologue or attach the node to the
 558         end of an existing prologue.
 559
 560         @since 2.9.2
 561     */
 562     void AppendToProlog(wxXmlNode* node);
 563
 564     /**
 565         Detaches the document node and returns it.
 566
 567         The document node will be set to @NULL and thus IsOk() will
 568         return @false after calling this function.
 569
 570         Note that the caller is responsible for deleting the returned node in order
 571         to avoid memory leaks.
 572
 573         @since 2.9.2
 574     */
 575     wxXmlNode* DetachDocumentNode();
 576
 577     /**
 578         Detaches the root entity node and returns it.
 579
 580         After calling this function, the document node will remain together with
 581         any prologue nodes, but IsOk() will return @false since the root entity
 582         will be missing.
 583
 584         Note that the caller is responsible for deleting the returned node in order
 585         to avoid memory leaks.
 586     */
 587     wxXmlNode* DetachRoot();
 588
 589     /**
 590         Returns encoding of in-memory representation of the document
 591         (same as passed to Load() or constructor, defaults to UTF-8).
 592
 593         @note this is meaningless in Unicode build where data are stored as @c wchar_t*.
 594     */
 595     wxString GetEncoding() const;
 596
 597     /**
 598         Returns encoding of document (may be empty).
 599
 600         @note This is the encoding original file was saved in, @b not the
 601               encoding of in-memory representation!
 602     */
 603     const wxString& GetFileEncoding() const;
 604
 605     /**
 606         Returns the document node of the document.
 607
 608         @since 2.9.2
 609     */
 610     wxXmlNode* GetDocumentNode() const;
 611
 612     /**
 613         Returns the root element node of the document.
 614     */
 615     wxXmlNode* GetRoot() const;
 616
 617     /**
 618         Returns the version of document.
 619
 620         This is the value in the @c \<?xml version="1.0"?\> header of the XML document.
 621         If the version attribute was not explicitly given in the header, this function
 622         returns an empty string.
 623     */
 624     const wxString& GetVersion() const;
 625
 626     /**
 627         Returns @true if the document has been loaded successfully.
 628     */
 629     bool IsOk() const;
 630
 631
 632     /**
 633         Parses @a filename as an xml document and loads its data.
 634
 635         If @a flags does not contain wxXMLDOC_KEEP_WHITESPACE_NODES, then, while loading,
 636         all nodes of type @c wxXML_TEXT_NODE (see wxXmlNode) are automatically skipped
 637         if they contain whitespaces only.
 638
 639         The removal of these nodes makes the load process slightly faster and requires
 640         less memory however makes impossible to recreate exactly the loaded text with a
 641         Save() call later. Read the initial description of this class for more info.
 642
 643         Returns true on success, false otherwise.
 644     */
 645     virtual bool Load(const wxString& filename,
 646                       const wxString& encoding = "UTF-8", int flags = wxXMLDOC_NONE);
 647
 648     /**
 649         Like Load(const wxString&, const wxString&, int) but takes the data from
 650         given input stream.
 651     */
 652     virtual bool Load(wxInputStream& stream,
 653                       const wxString& encoding = "UTF-8", int flags = wxXMLDOC_NONE);
 654
 655     /**
 656         Saves XML tree creating a file named with given string.
 657
 658         If @a indentstep is greater than or equal to zero, then, while saving,
 659         an automatic indentation is added with steps composed by indentstep spaces.
 660
 661         If @a indentstep is @c wxXML_NO_INDENTATION, then, automatic indentation
 662         is turned off.
 663     */
 664     virtual bool Save(const wxString& filename, int indentstep = 2) const;
 665
 666     /**
 667         Saves XML tree in the given output stream.
 668         See Save(const wxString&, int) for a description of @a indentstep.
 669     */
 670     virtual bool Save(wxOutputStream& stream, int indentstep = 2) const;
 671
 672     /**
 673         Sets the document node of this document.
 674
 675         Deletes any previous document node.
 676         Use DetachDocumentNode() and then SetDocumentNode() if you want to
 677         replace the document node without deleting the old document tree.
 678
 679         @since 2.9.2
 680     */
 681     void SetDocumentNode(wxXmlNode* node);
 682
 683     /**
 684         Sets the encoding of the document.
 685     */
 686     void SetEncoding(const wxString& enc);
 687
 688     /**
 689         Sets the enconding of the file which will be used to save the document.
 690     */
 691     void SetFileEncoding(const wxString& encoding);
 692
 693     /**
 694         Sets the root element node of this document.
 695
 696         Will create the document node if necessary. Any previous
 697         root element node is deleted.
 698     */
 699     void SetRoot(wxXmlNode* node);
 700
 701     /**
 702         Sets the version of the XML file which will be used to save the document.
 703     */
 704     void SetVersion(const wxString& version);
 705
 706     /**
 707         Deep copies the given document.
 708     */
 709     wxXmlDocument& operator=(const wxXmlDocument& doc);
 710
 711     /**
 712        Get expat library version information.
 713
 714        @since 2.9.2
 715        @see wxVersionInfo
 716     */
 717     static wxVersionInfo GetLibraryVersionInfo();
 718 };
 719