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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:24:48 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:24:48 +0000
commitcca66b9ec4e494c1d919bff0f71a820d8afab1fa (patch)
tree146f39ded1c938019e1ed42d30923c2ac9e86789 /src/xml/node.h
parentInitial commit. (diff)
downloadinkscape-upstream/1.2.2.tar.xz
inkscape-upstream/1.2.2.zip
Adding upstream version 1.2.2.upstream/1.2.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * @brief Interface for XML nodes
+ *
+ * Authors:
+ * MenTaLguY <mental@rydia.net>
+ * Krzysztof KosiƄski <tweenk.pl@gmail.com> (documentation)
+ *
+ * Copyright (C) 2018 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#ifndef SEEN_INKSCAPE_XML_NODE_H
+#define SEEN_INKSCAPE_XML_NODE_H
+
+#include <cassert>
+#include <vector>
+#include <list>
+#include <2geom/point.h>
+
+#include "gc-anchored.h"
+#include "inkgc/gc-alloc.h"
+#include "node-iterators.h"
+#include "util/const_char_ptr.h"
+#include "svg/svg-length.h"
+
+namespace Inkscape {
+namespace XML {
+
+class AttributeRecord;
+struct Document;
+class Event;
+class NodeObserver;
+struct NodeEventVector;
+
+typedef std::vector<AttributeRecord, Inkscape::GC::Alloc<AttributeRecord, Inkscape::GC::MANUAL>> AttributeVector;
+
+/**
+ * @brief Enumeration containing all supported node types.
+ */
+enum class NodeType
+{
+ DOCUMENT_NODE, ///< Top-level document node. Do not confuse with the root node.
+ ELEMENT_NODE, ///< Regular element node, e.g. &lt;group /&gt;.
+ TEXT_NODE, ///< Text node, e.g. "Some text" in &lt;group&gt;Some text&lt;/group&gt; is represented by a text node.
+ COMMENT_NODE, ///< Comment node, e.g. &lt;!-- some comment --&gt;
+ PI_NODE ///< Processing instruction node, e.g. &lt;?xml version="1.0" encoding="utf-8" standalone="no"?&gt;
+};
+
+// careful; GC::Anchored should only appear once in the inheritance
+// hierarchy; otherwise there will be leaks
+
+/**
+ * @brief Interface for refcounted XML nodes
+ *
+ * This class is an abstract base type for all nodes in an XML document - this includes
+ * everything except attributes. An XML document is also a node itself. This is the main
+ * class used for interfacing with Inkscape's documents. Everything that has to be stored
+ * in the SVG has to go through this class at some point.
+ *
+ * Each node unconditionally has to belong to a document. There are no "documentless" nodes,
+ * and it's not possible to move nodes between documents - they have to be duplicated.
+ * Each node can only refer to the nodes in the same document. Name of the node is immutable,
+ * it cannot be changed after its creation. Same goes for the type of the node. To simplify
+ * the use of this class, you can perform all operations on all nodes, but only some of them
+ * make any sense. For example, only element nodes can have attributes, only element and
+ * document nodes can have children, and all nodes except element and document nodes can
+ * have content. Although you can set content for element nodes, it won't make any difference
+ * in the XML output.
+ *
+ * To create new nodes, use the methods of the Inkscape::XML::Document class. You can obtain
+ * the nodes' document using the document() method. To destroy a node, just unparent it
+ * by calling sp_repr_unparent() or node->parent->removeChild() and release any references
+ * to it. The garbage collector will reclaim the memory in the next pass.
+ *
+ * In addition to regular DOM manipulations, you can register observer objects that will
+ * receive notifications about changes made to the node. See the NodeObserver class.
+ *
+ * @see Inkscape::XML::Document
+ * @see Inkscape::XML::NodeObserver
+ */
+class Node : public Inkscape::GC::Anchored {
+public:
+ Node() = default;
+ ~Node() override = default;
+
+ /**
+ * @name Retrieve information about the node
+ * @{
+ */
+
+ /**
+ * @brief Get the type of the node
+ * @return NodeType enumeration member corresponding to the type of the node.
+ */
+ virtual NodeType type() const = 0;
+
+ /**
+ * @brief Get the name of the element node
+ *
+ * This method only makes sense for element nodes. Names are stored as
+ * GQuarks to accelerate conversions.
+ *
+ * @return Name for element nodes, NULL for others
+ */
+ virtual char const *name() const = 0;
+ /**
+ * @brief Get the integer code corresponding to the node's name
+ * @return GQuark code corresponding to the name
+ */
+ virtual int code() const = 0;
+
+ /**
+ * @brief Get the index of this node in parent's child order
+ *
+ * If this method is used on a node that doesn't have a parent, the method will return 0,
+ * and a warning will be printed on the console.
+ *
+ * @return The node's index, or 0 if the node does not have a parent
+ */
+ virtual unsigned position() const = 0;
+
+ /**
+ * @brief Get the number of children of this node
+ * @return The number of children
+ */
+ virtual unsigned childCount() const = 0;
+
+ /**
+ * @brief Get the content of a text or comment node
+ *
+ * This method makes no sense for element nodes. To retrieve the element node's name,
+ * use the name() method.
+ *
+ * @return The node's content
+ */
+ virtual char const *content() const = 0;
+
+ /**
+ * @brief Get the string representation of a node's attribute
+ *
+ * If there is no attribute with the given name, the method will return NULL.
+ * All strings returned by this method are owned by the node and may not be freed.
+ * The returned pointer will become invalid when the attribute changes. If you need
+ * to store the return value, use g_strdup(). To parse the string, use methods
+ * in repr.h
+ *
+ * @param key The name of the node's attribute
+ */
+ virtual char const *attribute(char const *key) const = 0;
+
+ /**
+ * @brief Get a list of the node's attributes
+ *
+ * The returned list is a functional programming style list rather than a standard one.
+ *
+ * @return A list of AttributeRecord structures describing the attributes
+ * @todo This method should return std::map<Glib::Quark const, gchar const *>
+ * or something similar with a custom allocator
+ */
+ virtual const AttributeVector & attributeList() const=0;
+
+ /**
+ * @brief Check whether this node has any attribute that matches a string
+ *
+ * This method checks whether this node has any attributes whose names
+ * have @c partial_name as their substrings. The check is done using
+ * the strstr() function of the C library. I don't know what would require that
+ * functionality, because matchAttributeName("id") matches both "identity" and "hidden".
+ *
+ * @param partial_name The string to match against all attributes
+ * @return true if there is such an attribute, false otherwise
+ */
+ virtual bool matchAttributeName(char const *partial_name) const = 0;
+
+ /*@}*/
+
+ /**
+ * @name Modify the node
+ * @{
+ */
+
+ /**
+ * @brief Set the position of this node in parent's child order
+ *
+ * To move the node to the end of the parent's child order, pass a negative argument.
+ *
+ * @param pos The new position in parent's child order
+ */
+ virtual void setPosition(int pos) = 0;
+
+ /**
+ * @brief Set the content of a text or comment node
+ *
+ * This method doesn't make sense for element nodes.
+ *
+ * @param value The node's new content
+ */
+ virtual void setContent(char const *value) = 0;
+
+ //@{
+ /**
+ * @brief Change an attribute of this node
+ *
+ * The strings passed to this method are copied, so you can free them after use.
+ *
+ * @param key Name of the attribute to change
+ * @param value The new value of the attribute
+ * @param is_interactive Ignored
+ */
+
+ void setAttribute(Util::const_char_ptr key, Util::const_char_ptr value);
+
+ /**
+ * Parses the boolean value of an attribute "key" in repr and sets val accordingly, or to false if
+ * the attr is not set.
+ *
+ * \return true if the attr was set, false otherwise.
+ */
+ bool getAttributeBoolean(Util::const_char_ptr key, bool default_value = false) const;
+
+ int getAttributeInt(Util::const_char_ptr key, int default_value = 0) const;
+
+ double getAttributeDouble(Util::const_char_ptr key, double default_value = 0.0) const;
+
+ bool setAttributeBoolean(Util::const_char_ptr key, bool val);
+
+ bool setAttributeInt(Util::const_char_ptr key, int val);
+
+ /**
+ * Set a property attribute to \a val [slightly rounded], in the format
+ * required for CSS properties: in particular, it never uses exponent
+ * notation.
+ */
+ bool setAttributeCssDouble(Util::const_char_ptr key, double val);
+
+ /**
+ * For attributes where an exponent is allowed.
+ *
+ * Not suitable for property attributes (fill-opacity, font-size etc.).
+ */
+ bool setAttributeSvgDouble(Util::const_char_ptr key, double val);
+
+ bool setAttributeSvgNonDefaultDouble(Util::const_char_ptr key,
+ double val, double default_value);
+
+ bool setAttributeSvgLength(Util::const_char_ptr key, SVGLength const &val);
+
+ bool setAttributePoint(Util::const_char_ptr key, Geom::Point const &val);
+
+ Geom::Point getAttributePoint(Util::const_char_ptr key, Geom::Point default_value = {}) const;
+
+ /**
+ * @brief Change an attribute of this node. Empty string deletes the attribute.
+ *
+ * @param key Name of the attribute to change
+ * @param value The new value of the attribute
+ *
+ */
+ void setAttributeOrRemoveIfEmpty(Inkscape::Util::const_char_ptr key, Inkscape::Util::const_char_ptr value);
+
+ /**
+ * @brief Remove an attribute of this node
+ *
+ * @param key Name of the attribute to delete
+ *
+ */
+ void removeAttribute(Inkscape::Util::const_char_ptr key) { this->setAttributeImpl(key.data(), nullptr); }
+
+ //@}
+ /**
+ * @brief Set the integer GQuark code for the name of the node.
+ *
+ * Do not use this function unless you really have a good reason.
+ *
+ * @param code The integer value corresponding to the string to be set as
+ * the name of this node
+ */
+ virtual void setCodeUnsafe(int code) = 0;
+
+ /*@}*/
+
+ /**
+ * @name Traverse the XML tree
+ * @{
+ */
+
+ //@{
+ /**
+ * @brief Get the node's associated document
+ * @return The document to which the node belongs. Never NULL.
+ */
+ virtual Document *document() = 0;
+ virtual Document const *document() const = 0;
+ //@}
+
+ //@{
+ /**
+ * @brief Get the root node of this node's document
+ *
+ * This method works on any node that is part of an XML document, and returns
+ * the root node of the document in which it resides. For detached node hierarchies
+ * (i.e. nodes that are not descendants of a document node) this method
+ * returns the highest-level element node. For detached non-element nodes this method
+ * returns NULL.
+ *
+ * @return A pointer to the root element node, or NULL if the node is detached
+ */
+ virtual Node *root() = 0;
+ virtual Node const *root() const = 0;
+ //@}
+
+ //@{
+ /**
+ * @brief Get the parent of this node
+ *
+ * This method will return NULL for detached nodes.
+ *
+ * @return Pointer to the parent, or NULL
+ */
+ virtual Node *parent() = 0;
+ virtual Node const *parent() const = 0;
+ //@}
+
+ //@{
+ /**
+ * @brief Get the next sibling of this node
+ *
+ * This method will return NULL if the node is the last sibling element of the parent.
+ * The nodes form a singly-linked list, so there is no "prev()" method. Use the provided
+ * external function for that.
+ *
+ * @return Pointer to the next sibling, or NULL
+ * @see Inkscape::XML::previous_node()
+ */
+ virtual Node *next() = 0;
+ virtual Node const *next() const = 0;
+ virtual Node *prev() = 0;
+ virtual Node const *prev() const = 0;
+ //@}
+
+ //@{
+ /**
+ * @brief Get the first child of this node
+ *
+ * For nodes without any children, this method returns NULL.
+ *
+ * @return Pointer to the first child, or NULL
+ */
+ virtual Node *firstChild() = 0;
+ virtual Node const *firstChild() const = 0;
+ //@}
+
+ //@{
+ /**
+ * @brief Get the last child of this node
+ *
+ * For nodes without any children, this method returns NULL.
+ *
+ * @return Pointer to the last child, or NULL
+ */
+ virtual Node *lastChild() = 0;
+ virtual Node const *lastChild() const = 0;
+ //@}
+
+ //@{
+ /**
+ * @brief Get the child of this node with a given index
+ *
+ * If there is no child with the specified index number, this method will return NULL.
+ *
+ * @param index The zero-based index of the child to retrieve
+ * @return Pointer to the appropriate child, or NULL
+ */
+ virtual Node *nthChild(unsigned index) = 0;
+ virtual Node const *nthChild(unsigned index) const = 0;
+ //@}
+
+ /*@}*/
+
+ /**
+ * @name Manipulate the XML tree
+ * @{
+ */
+
+ /**
+ * @brief Create a duplicate of this node
+ *
+ * The newly created node has no parent, and a refcount equal 1.
+ * You need to manually insert it into the document, using e.g. appendChild().
+ * Afterwards, call Inkscape::GC::release on it, so that it will be
+ * automatically collected when the parent is collected.
+ *
+ * @param doc The document in which the duplicate should be created
+ * @return A pointer to the duplicated node
+ */
+ virtual Node *duplicate(Document *doc) const = 0;
+
+ /**
+ * @brief Insert another node as a child of this node
+ *
+ * When @c after is NULL, the inserted node will be placed as the first child
+ * of this node. @c after must be a child of this node.
+ *
+ * @param child The node to insert
+ * @param after The node after which the inserted node should be placed, or NULL
+ */
+ virtual void addChild(Node *child, Node *after) = 0;
+
+ /**
+ * @brief Insert another node as a child of this node
+ *
+ * This is more efficient than appendChild() + setPosition().
+ *
+ * @param child The node to insert
+ * @param pos The position in parent's child order
+ */
+ void addChildAtPos(Node *child, unsigned pos)
+ {
+ Node *after = (pos == 0) ? nullptr : nthChild(pos - 1);
+ addChild(child, after);
+ }
+
+ /**
+ * @brief Append a node as the last child of this node
+ * @param child The node to append
+ */
+ virtual void appendChild(Node *child) = 0;
+
+ /**
+ * @brief Remove a child of this node
+ *
+ * Once the pointer to the removed node disappears from the stack, the removed node
+ * will be collected in the next GC pass, but only as long as its refcount is zero.
+ * You should keep a refcount of zero for all nodes in the document except for
+ * the document node itself, because they will be held in memory by the parent.
+ *
+ * @param child The child to remove
+ */
+ virtual void removeChild(Node *child) = 0;
+
+ /**
+ * @brief Move a given node in this node's child order
+ *
+ * Both @c child and @c after must be children of this node for the method to work.
+ *
+ * @param child The node to move in the order
+ * @param after The sibling node after which the moved node should be placed
+ */
+ virtual void changeOrder(Node *child, Node *after) = 0;
+
+ /**
+ * @brief Remove all elements that not in src node
+ * @param src The node to check for elements into this node
+ * @param key The attribute to use as the identity attribute
+ */
+ virtual void cleanOriginal(Node *src, gchar const *key) = 0;
+
+ /**
+ * @brief Compare 2 nodes equality
+ * @param other The other node to compare
+ * @param recursive Recursive mode check
+ */
+ virtual bool equal(Node const *other, bool recursive) = 0;
+ /**
+ * @brief Merge all children of another node with the current
+ *
+ * This method merges two node hierarchies, where @c src takes precedence.
+ * @c key is the name of the attribute that determines whether two nodes are
+ * corresponding (it must be the same for both, and all of their ancestors). If there is
+ * a corresponding node in @c src hierarchy, their attributes and content override the ones
+ * already present in this node's hierarchy. If there is no corresponding node,
+ * it is copied from @c src to this node. This method is used when merging the user's
+ * preferences file with the defaults, and has little use beyond that.
+ *
+ * @param src The node to merge into this node
+ * @param key The attribute to use as the identity attribute
+ * @param noid If true process noid items
+ * @param key If clean callback to cleanOriginal
+ */
+
+ virtual void mergeFrom(Node const *src, char const *key, bool extension = false, bool clean = false) = 0;
+
+ /*@}*/
+
+
+ /**
+ * @name Notify observers about operations on the node
+ * @{
+ */
+
+ /**
+ * @brief Add an object that will be notified of the changes to this node
+ *
+ * @c observer must be an object deriving from the NodeObserver class.
+ * The virtual methods of this object will be called when a corresponding change
+ * happens to this node. You can also notify the observer of the node's current state
+ * using synthesizeEvents(NodeObserver &).
+ *
+ * @param observer The observer object
+ */
+ virtual void addObserver(NodeObserver &observer) = 0;
+ /**
+ * @brief Remove an object from the list of observers
+ * @param observer The object to be removed
+ */
+ virtual void removeObserver(NodeObserver &observer) = 0;
+ /**
+ * @brief Generate a sequence of events corresponding to the state of this node
+ *
+ * This function notifies the specified observer of all the events that would
+ * recreate the current state of this node; e.g. the observer is notified of
+ * all the attributes, children and content like they were just created.
+ * This function can greatly simplify observer logic.
+ *
+ * @param observer The node observer to notify of the events
+ */
+ virtual void synthesizeEvents(NodeObserver &observer) = 0;
+
+ /**
+ * @brief Add an object that will be notified of the changes to this node and its descendants
+ *
+ * The difference between adding a regular observer and a subtree observer is that
+ * the subtree observer will also be notified if a change occurs to any of the node's
+ * descendants, while a regular observer will only be notified of changes to the node
+ * it was assigned to.
+ *
+ * @param observer The observer object
+ */
+ virtual void addSubtreeObserver(NodeObserver &observer) = 0;
+
+ /**
+ * @brief Remove an object from the subtree observers list
+ * @param observer The object to be removed
+ */
+ virtual void removeSubtreeObserver(NodeObserver &observer) = 0;
+
+ /**
+ * @brief Add a set node change callbacks with an associated data
+ * @deprecated Use addObserver(NodeObserver &) instead
+ */
+ virtual void addListener(NodeEventVector const *vector, void *data) = 0;
+ /**
+ * @brief Remove a set of node change callbacks by their associated data
+ * @deprecated Use removeObserver(NodeObserver &) instead
+ */
+ virtual void removeListenerByData(void *data) = 0;
+ /**
+ * @brief Generate a sequence of events corresponding to the state of this node
+ * @deprecated Use synthesizeEvents(NodeObserver &) instead
+ */
+ virtual void synthesizeEvents(NodeEventVector const *vector, void *data) = 0;
+
+ virtual void recursivePrintTree(unsigned level) = 0;
+
+ /*@}*/
+
+ using iterator = Inkscape::XML::NodeSiblingIterator;
+
+ /** @brief Iterator over children */
+ iterator begin() { return iterator(this->firstChild()); }
+ /** @brief Helper to use the standard lib container functions */
+ iterator end() { return iterator(nullptr); }
+
+ /** @brief Compare a node by looking at its name to a string */
+ bool operator==(const std::string &name) const { return this->name() == name; }
+
+ /** @brief depth first search to find a node
+ *
+ * This function takes any list structure you want and uses that
+ * to compare Node's down the child tree. It will do depth first
+ * searching into the tree. The key part is that since it is a template
+ * you have flexibility on the container, and the comparison that is
+ * being used. Typically it will be used with something like a
+ * std::list<std::string> which will compare against the node's name
+ * but more complex searches could be imagined.
+ */
+ template <typename T>
+ Node *findChildPath(T list)
+ {
+ return findChildPath(list.cbegin(), list.cend());
+ }
+
+ /** @brief template reshuffling to make the more useful findChildPath cleaner */
+ template <typename iterT>
+ Node *findChildPath(iterT itr, iterT end)
+ {
+ if (itr == end) {
+ return this;
+ }
+
+ for (auto &child : *this) {
+ if (child == *itr) {
+ auto found = child.findChildPath(std::next(itr), end);
+ if (found != nullptr) {
+ return found;
+ }
+ }
+ }
+
+ return nullptr;
+ }
+
+protected:
+ Node(Node const &)
+ : Anchored()
+ {}
+
+ virtual void setAttributeImpl(char const *key, char const *value) = 0;
+};
+
+} // namespace XML
+} // namespace Inkscape
+
+#endif
+/*
+ Local Variables:
+ mode:c++
+ c-file-style:"stroustrup"
+ c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+ indent-tabs-mode:nil
+ fill-column:99
+ End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :