r3468 jmb - in /trunk/dom/src/core: document.c document.h node.c

Author: jmb Date: Sun Jul 29 00:03:56 2007 New Revision: 3468 URL: http://source.netsurf-browser.org?rev=3468&view=rev Log: Implement Document destructor. Fix handling of nodes within a document (they no longer explicitly reference the document) Modified: trunk/dom/src/core/document.c trunk/dom/src/core/document.h trunk/dom/src/core/node.c Modified: trunk/dom/src/core/document.c URL: http://source.netsurf-browser.org/trunk/dom/src/core/document.c?rev=3468&... ============================================================================== --- trunk/dom/src/core/document.c (original) +++ trunk/dom/src/core/document.c Sun Jul 29 00:03:56 2007 @@ -138,8 +138,10 @@ } } - /* Initialise base class */ - err = dom_node_initialise(&d->base, d, DOM_DOCUMENT_NODE, + /* Initialise base class -- the Document has no parent, so + * destruction will be attempted as soon as its reference count + * reaches zero. */ + err = dom_node_initialise(&d->base, NULL, DOM_DOCUMENT_NODE, NULL, NULL); if (err != DOM_NO_ERR) { /* Clean up interned strings */ @@ -165,6 +167,79 @@ *doc = d; return DOM_NO_ERR; +} + +/** + * Destroy a document + * + * \param doc The document to destroy + * + * The contents of ::doc will be destroyed and ::doc will be freed. + */ +void dom_document_destroy(struct dom_document *doc) +{ + struct dom_node *c, *d; + + /* Destroy children of this node */ + for (c = doc->base.first_child; c != NULL; c = d) { + d = c->next; + + /* Detach child */ + c->parent = NULL; + + if (c->refcnt > 0) { + /* Something is using this child */ + + /** \todo add to list of nodes pending deletion */ + + continue; + } + + /* Detach from sibling list */ + c->previous = NULL; + c->next = NULL; + + dom_node_destroy(c); + } + + /** \todo Ensure list of nodes pending deletion is empty. If not, + * then we can't yet destroy the document (its destruction will + * have to wait until the pending nodes are destroyed) */ + + /* Ok, the document tree is empty, as is the list of nodes pending + * deletion. Therefore, it is safe to destroy the document. */ + + /* Destroy the doctype (if there is one) */ + if (doc->type != NULL) { + ((struct dom_node *) doc->type)->parent = NULL; + + dom_node_destroy((struct dom_node *) doc->type); + } + + doc->type = NULL; + + if (doc->impl != NULL) + dom_implementation_unref(doc->impl); + doc->impl = NULL; + + /* This is paranoia -- if there are any remaining nodelists or + * namednodemaps, then the document's reference count will be + * non-zero as these data structures reference the document because + * they are held by the client. */ + doc->nodelists = NULL; + doc->maps = NULL; + + /* Clean up interned strings */ + for (int i = 0; i <= DOM_NODE_TYPE_COUNT; i++) { + if (doc->nodenames[i] != NULL) + dom_string_unref(doc->nodenames[i]); + } + + /* Finalise base class */ + dom_node_finalise(doc, &doc->base); + + /* Free document */ + doc->alloc(doc, 0, doc->pw); } /** Modified: trunk/dom/src/core/document.h URL: http://source.netsurf-browser.org/trunk/dom/src/core/document.h?rev=3468&... ============================================================================== --- trunk/dom/src/core/document.h (original) +++ trunk/dom/src/core/document.h Sun Jul 29 00:03:56 2007 @@ -18,6 +18,9 @@ struct dom_node; struct dom_nodelist; struct dom_string; + +/* Destroy a document */ +void dom_document_destroy(struct dom_document *doc); /* Get base of document buffer */ const uint8_t *dom_document_get_base(struct dom_document *doc); Modified: trunk/dom/src/core/node.c URL: http://source.netsurf-browser.org/trunk/dom/src/core/node.c?rev=3468&... ============================================================================== --- trunk/dom/src/core/node.c (original) +++ trunk/dom/src/core/node.c Sun Jul 29 00:03:56 2007 @@ -39,10 +39,11 @@ struct dom_document *owner = node->owner; /* This function simply acts as a central despatcher - * for type-specific destructors. It claims a reference upon the - * owning document during destruction to ensure that the document - * doesn't get destroyed before its contents. */ - + * for type-specific destructors. */ + + /* Claim a reference upon the owning document during destruction + * to ensure that the document doesn't get destroyed before its + * contents. */ dom_node_ref((struct dom_node *) owner); switch (node->type) { @@ -74,7 +75,7 @@ dom_comment_destroy(owner, (struct dom_comment *) node); break; case DOM_DOCUMENT_NODE: - /** \todo document node */ + dom_document_destroy((struct dom_document *) node); break; case DOM_DOCUMENT_TYPE_NODE: /** \todo document type node */ @@ -88,6 +89,9 @@ break; } + /* Release the reference we claimed on the document. If this is + * the last reference held on the document and the list of nodes + * pending deletion is empty, then the document will be destroyed. */ dom_node_unref((struct dom_node *) owner); } @@ -124,7 +128,24 @@ node->next = NULL; node->attributes = NULL; - dom_node_ref((struct dom_node *) doc); + /* Note: nodes do not reference the document to which they belong, + * as this would result in the document never being destroyed once + * the client has finished with it. The document will be aware of + * any nodes that it owns through 2 mechanisms: + * + * either a) Membership of the document tree + * or b) Membership of the list of nodes pending deletion + * + * It is not possible for any given node to be a member of both + * data structures at the same time. + * + * The document will not be destroyed until both of these + * structures are empty. It will forcibly attempt to empty + * the document tree on document destruction. Any still-referenced + * nodes at that time will be added to the list of nodes pending + * deletion. This list will not be forcibly emptied, as it contains + * those nodes (and their sub-trees) in use by client code. + */ node->owner = doc; /** \todo Namespace handling */ @@ -170,7 +191,9 @@ if (node->namespace != NULL) dom_string_unref(node->namespace); - dom_node_unref((struct dom_node *) node->owner); + /** \todo check if this node is in list of nodes pending deletion. + * If so, it must be removed from the list, so the document gets + * destroyed once the list is empty (and no longer referenced) */ node->owner = NULL; /* Paranoia */