LibWeb: Give each Node a unique ID

We maintain a directory of ID -> Node. Nodes add themselves to this
directory when they are created, receiving a random ID. When a Node is
destroyed, it removes itself from this directory. Anyone can request a
Node from the directory by its ID using `Node::from_id()`.

We reserve the `0` ID to mean "none".

These IDs allow different processes to communicate about a given Node
over IPC, for example the DOM Inspector.
This commit is contained in:
Sam Atkins 2021-08-30 15:52:08 +01:00 committed by Andreas Kling
parent 48a2239f60
commit d7485df928
Notes: sideshowbarker 2024-07-18 04:52:24 +09:00
3 changed files with 33 additions and 0 deletions

View file

@ -8,6 +8,7 @@
#include <AK/FlyString.h>
#include <AK/Function.h>
#include <AK/HashMap.h>
#include <AK/NonnullRefPtrVector.h>
#include <AK/OwnPtr.h>
#include <AK/String.h>

View file

@ -6,6 +6,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/IDAllocator.h>
#include <AK/StringBuilder.h>
#include <LibJS/AST.h>
#include <LibJS/Runtime/FunctionObject.h>
@ -30,10 +31,33 @@
namespace Web::DOM {
static IDAllocator s_node_id_allocator;
static HashMap<i32, Node*> s_node_directory;
static i32 allocate_node_id(Node* node)
{
i32 id = s_node_id_allocator.allocate();
s_node_directory.set(id, node);
return id;
}
static void deallocate_node_id(i32 node_id)
{
if (!s_node_directory.remove(node_id))
VERIFY_NOT_REACHED();
s_node_id_allocator.deallocate(node_id);
}
Node* Node::from_id(i32 node_id)
{
return s_node_directory.get(node_id).value_or(nullptr);
}
Node::Node(Document& document, NodeType type)
: EventTarget(static_cast<Bindings::ScriptExecutionContext&>(document))
, m_document(&document)
, m_type(type)
, m_id(allocate_node_id(this))
{
if (!is_document())
m_document->ref_from_node({});
@ -47,6 +71,8 @@ Node::~Node()
if (!is_document())
m_document->unref_from_node({});
deallocate_node_id(m_id);
}
const HTML::HTMLAnchorElement* Node::enclosing_link_element() const
@ -477,6 +503,7 @@ void Node::set_document(Badge<Document>, Document& document)
{
if (m_document == &document)
return;
document.ref_from_node({});
m_document->unref_from_node({});
m_document = &document;

View file

@ -179,6 +179,9 @@ public:
bool is_shadow_including_ancestor_of(Node const&) const;
bool is_shadow_including_inclusive_ancestor_of(Node const&) const;
i32 id() const { return m_id; }
static Node* from_id(i32 node_id);
protected:
Node(Document&, NodeType);
@ -187,6 +190,8 @@ protected:
NodeType m_type { NodeType::INVALID };
bool m_needs_style_update { false };
bool m_child_needs_style_update { false };
i32 m_id;
};
}