140 lines
4.4 KiB
C
140 lines
4.4 KiB
C
/**
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* This file is part of the Fun programming language.
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* https://fun-lang.xyz/
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*
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* Copyright 2025 Johannes Findeisen <you@hanez.org>
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* Licensed under the terms of the Apache-2.0 license.
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* https://opensource.org/license/apache-2-0
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*/
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/**
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* @file xml2.c
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* @brief Lightweight libxml2 handle registry for Fun VM extension helpers.
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*
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* This module provides small fixed-size registries for libxml2 objects when
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* compiled with FUN_WITH_XML2. Documents and nodes can be associated with
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* small integer handles to make them easier to pass around inside the
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* interpreter and its C API boundaries. The document registry owns the
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* underlying xmlDoc, while the node registry does not own the xmlNode — nodes
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* are freed when their owning document is freed.
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*
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* Limits: The registries are fixed-size (docs: 64, nodes: 256). Handle value 0
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* is reserved and indicates failure/invalid.
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*
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* Thread-safety: Not thread-safe. Coordinate access externally if needed.
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*/
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#ifdef FUN_WITH_XML2
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#include <libxml/parser.h>
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#include <libxml/tree.h>
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/**
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* @brief Slot describing a registered XML document.
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*
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* The registry owns the xmlDocPtr and will free it when the handle is
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* released via xml_doc_free_handle().
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*/
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typedef struct {
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xmlDocPtr doc;
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int in_use;
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} XmlDocSlot;
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/**
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* @brief Slot describing a registered XML node.
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*
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* The registry does not own the node; it is managed by its document. Releasing
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* a node handle does not free the node memory.
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*/
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typedef struct {
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xmlNodePtr node;
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int in_use;
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} XmlNodeSlot;
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static XmlDocSlot g_xml_docs[64];
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static XmlNodeSlot g_xml_nodes[256];
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/**
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* @brief Allocate a document handle for the given xmlDoc pointer.
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*
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* @param d Valid xmlDocPtr to register. Ownership is transferred to the
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* registry, which will xmlFreeDoc() it when the handle is freed.
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* @return Positive handle in the range [1, 63] on success; 0 if no slot is
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* available.
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*/
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static int xml_doc_alloc(xmlDocPtr d) {
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for (int i = 1; i < (int)(sizeof(g_xml_docs) / sizeof(g_xml_docs[0])); ++i) {
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if (!g_xml_docs[i].in_use) {
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g_xml_docs[i].in_use = 1;
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g_xml_docs[i].doc = d;
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return i;
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}
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}
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return 0;
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}
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/**
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* @brief Retrieve a registered xmlDoc by handle.
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*
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* @param h Handle previously returned by xml_doc_alloc().
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* @return xmlDocPtr if the handle is valid and in use; NULL otherwise.
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*/
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static xmlDocPtr xml_doc_get(int h) {
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if (h > 0 && h < (int)(sizeof(g_xml_docs) / sizeof(g_xml_docs[0])) && g_xml_docs[h].in_use) return g_xml_docs[h].doc;
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return NULL;
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}
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/**
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* @brief Free a document handle and the underlying xmlDoc.
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*
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* @param h Handle to release.
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* @return 1 if the handle was valid and has been released; 0 otherwise.
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*/
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static int xml_doc_free_handle(int h) {
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if (h <= 0 || h >= (int)(sizeof(g_xml_docs) / sizeof(g_xml_docs[0])) || !g_xml_docs[h].in_use) return 0;
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if (g_xml_docs[h].doc) xmlFreeDoc(g_xml_docs[h].doc);
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g_xml_docs[h].doc = NULL;
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g_xml_docs[h].in_use = 0;
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return 1;
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}
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/**
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* @brief Allocate a node handle for the given xmlNode pointer.
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*
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* @param n Valid xmlNodePtr to register. Ownership is NOT transferred;
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* nodes are managed by their owning document.
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* @return Positive handle in the range [1, 255] on success; 0 if no slot is
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* available.
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*/
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static int xml_node_alloc(xmlNodePtr n) {
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for (int i = 1; i < (int)(sizeof(g_xml_nodes) / sizeof(g_xml_nodes[0])); ++i) {
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if (!g_xml_nodes[i].in_use) {
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g_xml_nodes[i].in_use = 1;
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g_xml_nodes[i].node = n;
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return i;
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}
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}
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return 0;
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}
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/**
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* @brief Retrieve a registered xmlNode by handle.
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*
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* @param h Handle previously returned by xml_node_alloc().
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* @return xmlNodePtr if the handle is valid and in use; NULL otherwise.
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*/
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static xmlNodePtr xml_node_get(int h) {
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if (h > 0 && h < (int)(sizeof(g_xml_nodes) / sizeof(g_xml_nodes[0])) && g_xml_nodes[h].in_use) return g_xml_nodes[h].node;
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return NULL;
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}
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/**
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* @brief Free a node handle without freeing the underlying node.
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*
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* Nodes are owned by their document; releasing the document invalidates any
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* associated node handles.
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*
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* @param h Handle to release.
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* @return 1 if the handle was valid and has been released; 0 otherwise.
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*/
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static int xml_node_free_handle(int h) {
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if (h <= 0 || h >= (int)(sizeof(g_xml_nodes) / sizeof(g_xml_nodes[0])) || !g_xml_nodes[h].in_use) return 0;
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/* nodes are owned by their document; do not free here */
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g_xml_nodes[h].node = NULL;
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g_xml_nodes[h].in_use = 0;
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return 1;
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}
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#endif
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