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// 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_BROWSER_RENDERER_HOST_NAVIGATION_ENTRY_RESTORE_CONTEXT_IMPL_H_
#define CONTENT_BROWSER_RENDERER_HOST_NAVIGATION_ENTRY_RESTORE_CONTEXT_IMPL_H_
#include <map>
#include <string>
#include "base/memory/raw_ptr.h"
#include "content/common/content_export.h"
#include "content/public/browser/navigation_entry_restore_context.h"
#include "url/gurl.h"
namespace content {
class FrameNavigationEntry;
// NavigationEntryRestoreContextImpl is passed to
// NavigationEntry::SetPageState() when restoring a vector of NavigationEntries.
// It tracks the item sequence number (ISNs) associated with each
// FrameNavigationEntry (FNE), and maintains a mapping of ISNs to FNEs to
// ensure FNEs are de-duplicated if they appear in multiple NavigationEntries.
class CONTENT_EXPORT NavigationEntryRestoreContextImpl
: public NavigationEntryRestoreContext {
public:
NavigationEntryRestoreContextImpl();
~NavigationEntryRestoreContextImpl() override;
NavigationEntryRestoreContextImpl(const NavigationEntryRestoreContextImpl&) =
delete;
NavigationEntryRestoreContextImpl& operator=(
const NavigationEntryRestoreContextImpl&) = delete;
void AddFrameNavigationEntry(FrameNavigationEntry* entry);
// If there is an existing FrameNavigationEntry with the given
// |item_sequence_number| targeting |unique_name|, this returns it so that it
// can be shared. Entries with the same ISN and unique name may differ by URL
// if they were persisted from an earlier version, so this indexes by URL as
// well.
FrameNavigationEntry* GetFrameNavigationEntry(int64_t item_sequence_number,
const std::string& unique_name,
const GURL& url);
private:
// RestoreContext entries are indexed by item sequence number, unique name of
// the frame, and URL. The unique name is a precaution in case the item
// sequence number somehow appears in multiple frames. The URL is needed to
// handle cases from older versions where a replaceState operation might have
// caused multiple FrameNavigationEntries with the same ISN and unique name to
// have different URLs.
//
// We also ensure that entries with an item sequence number of 0 (the default
// value) cannot be stored or retrieved, since they may not represent the same
// document. This may happen for entries restored without all available state,
// and we can skip FrameNavigationEntry sharing for them because they are not
// considered same-document anyway.
class Key {
public:
Key(int64_t isn, const std::string& name, const GURL& entry_url)
: item_sequence_number_(isn), unique_name_(name), url_(entry_url) {}
// Avoid copying of the Key as it contains strings.
Key(const Key&) = delete;
Key& operator=(const Key&) = delete;
Key(Key&& other) = default;
Key& operator=(Key&& other) = default;
struct Compare {
bool operator()(const Key& x, const Key& y) const;
};
private:
// These values are non-const so that the Key is movable. They should
// otherwise never change.
int64_t item_sequence_number_;
std::string unique_name_;
GURL url_;
};
std::map<Key, raw_ptr<FrameNavigationEntry, CtnExperimental>, Key::Compare>
entries_;
};
} // namespace content
#endif // CONTENT_BROWSER_RENDERER_HOST_NAVIGATION_ENTRY_RESTORE_CONTEXT_IMPL_H_
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