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content / public / browser / weak_document_ptr.h [blame]
// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_PUBLIC_BROWSER_WEAK_DOCUMENT_PTR_H_
#define CONTENT_PUBLIC_BROWSER_WEAK_DOCUMENT_PTR_H_
#include "base/memory/weak_ptr.h"
#include "content/common/content_export.h"
namespace content {
class RenderFrameHost;
// Weakly refers to a document.
//
// This is invalidated at the same time as DocumentUserData. It
// becomes null whenever the RenderFrameHost is deleted or navigates to a
// different document. See also document_user_data.h.
//
// Note that though this is implemented as a base::WeakPtr<RenderFrameHost>,
// it is different from an ordinary weak pointer to the RenderFrameHost.
//
// docs/render_document.md will make these equivalent in the future.
//
// Treat this like you would a base::WeakPtr, because that's essentially what it
// is.
class WeakDocumentPtr {
public:
WeakDocumentPtr();
// Copyable and movable.
WeakDocumentPtr(WeakDocumentPtr&&);
WeakDocumentPtr& operator=(WeakDocumentPtr&&);
WeakDocumentPtr(const WeakDocumentPtr&);
WeakDocumentPtr& operator=(const WeakDocumentPtr&);
~WeakDocumentPtr();
// Callers must handle this returning null, in case the frame has been deleted
// or a cross-document navigation has committed in the same RenderFrameHost.
RenderFrameHost* AsRenderFrameHostIfValid() const {
return weak_document_.get();
}
private:
explicit WeakDocumentPtr(base::WeakPtr<RenderFrameHost> weak_rfh);
friend class RenderFrameHostImpl;
// Created from a factory scoped to document, rather than RenderFrameHost,
// lifetime.
base::WeakPtr<RenderFrameHost> weak_document_;
};
// [chromium-style] requires these be out of line, but they are small enough to
// inline the defaults.
inline WeakDocumentPtr::WeakDocumentPtr() = default;
inline WeakDocumentPtr::WeakDocumentPtr(WeakDocumentPtr&&) = default;
inline WeakDocumentPtr& WeakDocumentPtr::operator=(WeakDocumentPtr&&) = default;
inline WeakDocumentPtr::WeakDocumentPtr(const WeakDocumentPtr&) = default;
inline WeakDocumentPtr& WeakDocumentPtr::operator=(const WeakDocumentPtr&) =
default;
inline WeakDocumentPtr::~WeakDocumentPtr() = default;
} // namespace content
#endif // CONTENT_PUBLIC_BROWSER_WEAK_DOCUMENT_PTR_H_