forked from KolibriOS/kolibrios
203 lines
7.6 KiB
Plaintext
203 lines
7.6 KiB
Plaintext
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Hubbub treebuilding interface
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=============================
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Introduction
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------------
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hubbub uses an interface to build a tree. this is what the functions should
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do.
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Types
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-----
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hubbub_string
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-------------
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Reference counting
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------------------
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The callback interface provides hooks to allow tree nodes to be reference
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counted. There is, however, no requirement that the client actually performs
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reference counting. It is perfectly acceptable to use some other object use
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tracking scheme (e.g. garbage collection). The descriptions below describe
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the expected reference counting behaviour, regardless.
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Callback behaviour
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------------------
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The first parameter to all callbacks is the context passed to the library
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on initialisation.
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All node creation functions should return 0 on success, and something else
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on failure.
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Node creation
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-------------
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| int hubbub_tree_create_comment(void *ctx,
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| const hubbub_string *data,
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| void **result);
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| int hubbub_tree_create_doctype(void *ctx,
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| const hubbub_doctype *doctype,
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| void **result);
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| int hubbub_tree_create_element(void *ctx,
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| const hubbub_tag *tag,
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| void **result);
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| int hubbub_tree_create_text(void *ctx,
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| const hubbub_string *data,
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| void **result);
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All node creation functions must create a node with the information passed
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in their second argument, and place a pointer to that node in *result. The
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reference count of the created node must be set to 1.
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| int hubbub_tree_clone_node(void *ctx,
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| void *node,
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| bool deep,
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| void **result);
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If deep == false, then this function must duplicate "node" and none of its
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children, and place a pointer to the clone in *result. It must also set the
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reference count of the clone to 1. The clone must be isolated from the
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document tree (it must have no parent or sibling nodes).
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If deep == true, then this function must duplicate "node" and all of its
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children. A pointer to the clone of "node" must be placed in *result. The
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reference count of the clone must be set to 1. The reference count of all
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other created nodes must be set to 0. The clone must also be isolated from
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the document tree (it must have no parent or sibling nodes).
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Reference counting
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------------------
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| int hubbub_tree_ref_node(void *ctx, void *node);
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| int hubbub_tree_unref_node(void *ctx, void *node);
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These functions should increase and decrease the reference count of "node",
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respectively. If the reference count of "node" falls to zero, and it is
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isolated from the document tree (it has no parent or sibling nodes), then
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it must be destroyed.
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Tree manipulation
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-----------------
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| int hubbub_tree_append_child(void *ctx,
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| void *parent,
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| void *child,
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| void **result);
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This function must append the node "child" to the end of the list of children
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of the node "parent", and place a pointer to the newly-inserted node in
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*result.
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If the node "child" is a text node, and the last child node of "parent" is
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also a text node, then instead the text of "child" must be appended to that
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node, and a pointer to the node thus appended to must be placed in *result.
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In any case, the reference count of the node pointed to by *result at the end
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of these steps must be incremented.
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| int hubbub_tree_insert_before(void *ctx,
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| void *parent,
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| void *child,
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| void *ref_child,
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| void **result);
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This function must insert the node "child" into the list of children of
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"parent" immediately before the node "ref_child", and place a pointer to the
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newly-inserted node in *result.
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If the node "child" is a text node, and the node "ref_child" or the node
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before "ref_child" is also a text node, then instead the text of "child" must
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be prepended to the text of "ref_child", or appended to the text of node
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before "ref_node", and a pointer to the node thus appended to must be placed
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in *result.
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In any case, the reference count of the node pointed to by *result at the end
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of these steps must be incremented.
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| int hubbub_tree_remove_child(void *ctx,
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| void *parent,
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| void *child,
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| void **result);
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This function must remove the node "child" from the document tree. It must
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increment the reference count of the node "child", and place a pointer to
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the newly-removed node in *result.
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| int hubbub_tree_reparent_children(void *ctx,
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| void *node,
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| void *new_parent);
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This function must detach all children from "node" and insert them into
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"new_parent" in the same order as they were found in "node".
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| int hubbub_tree_get_parent(void *ctx,
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| void *node,
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| bool element_only,
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| void **result);
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This function must retrieve the parent of "node". If there is no parent
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node, then NULL must be placed in *result. Otherwise, it must increment
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the reference count of the parent, and place a pointer to the parent in
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*result.
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If "element_only" == true and the retrieved parent is not an element node,
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then act as if no parent exists.
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| int hubbub_tree_has_children(void *ctx,
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| void *node,
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| bool *result);
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If "node" has any child nodes attached to it, then *result must be set to
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true. Otherwise, *result must be set to false.
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| int hubbub_tree_form_associate(void *ctx,
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| void *form,
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| void *node);
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This function must associate "node" with the node "form" (which is the
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currently active form element).
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| int hubbub_tree_add_attributes(void *ctx,
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| void *node,
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| const hubbub_attribute *attributes,
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| uint32_t n_attributes);
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For each attribute in the array "attributes", this function must check to
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see if there is such an attribute already present on "node". If there is
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not such an attribute, then the attribute must be added to "node".
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| int hubbub_tree_set_quirks_mode(void *ctx,
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| hubbub_quirks_mode mode);
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This function must set the quirks mode flag of the document to "mode".
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| int hubbub_tree_encoding_change(void *ctx,
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| const char *name);
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This function is called when a meta tag which specifies a charset is seen
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in the treebuilder. [1] The client is responsible for checking if the
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encoding the document is being processed as should actually be changed, and
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if it should, this function should return 1. In this case, the parser
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instance will return the error code HUBBUB_ENCODINGCHANGE when it returns
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from parsing the chunk that triggered the encoding change. The parser
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instance should then be destroyed and a new one created with that encoding
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specified.
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[1] http://www.whatwg.org/specs/web-apps/current-work/#in-head
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