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AK: Move AK::Detail::StringData to its own header file

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This will allow us to access it from FlyString.cpp
This commit is contained in:
Andreas Kling 2024-03-23 12:18:54 +01:00
parent f1f7e89b68
commit 8bfad24708
Notes: sideshowbarker 2024-07-16 23:57:20 +09:00
2 changed files with 140 additions and 125 deletions
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126
AK/StringBase.cpp
View file

@ -7,134 +7,10 @@
#include <AK/Badge.h> #include <AK/Badge.h>
#include <AK/FlyString.h> #include <AK/FlyString.h>
#include <AK/StringBase.h> #include <AK/StringBase.h>
#include <AK/StringData.h>
namespace AK::Detail { namespace AK::Detail {
class StringData final : public RefCounted<StringData> {
public:
static ErrorOr<NonnullRefPtr<StringData>> create_uninitialized(size_t byte_count, u8*& buffer)
{
VERIFY(byte_count);
void* slot = malloc(allocation_size_for_string_data(byte_count));
if (!slot) {
return Error::from_errno(ENOMEM);
}
auto new_string_data = adopt_ref(*new (slot) StringData(byte_count));
buffer = const_cast<u8*>(new_string_data->bytes().data());
return new_string_data;
}
static ErrorOr<NonnullRefPtr<StringData>> create_substring(StringData const& superstring, size_t start, size_t byte_count)
{
// Strings of MAX_SHORT_STRING_BYTE_COUNT bytes or less should be handled by the String short string optimization.
VERIFY(byte_count > MAX_SHORT_STRING_BYTE_COUNT);
void* slot = malloc(sizeof(StringData) + sizeof(StringData::SubstringData));
if (!slot) {
return Error::from_errno(ENOMEM);
}
return adopt_ref(*new (slot) StringData(superstring, start, byte_count));
}
struct SubstringData {
StringData const* superstring { nullptr };
u32 start_offset { 0 };
};
void operator delete(void* ptr)
{
free(ptr);
}
void unref() const
{
if (m_is_fly_string && m_ref_count == 2) {
m_is_fly_string = false; // Otherwise unref from did_destory_fly_string_data will cause infinite recursion.
FlyString::did_destroy_fly_string_data({}, bytes_as_string_view());
}
RefCounted::unref();
}
~StringData()
{
if (m_substring)
substring_data().superstring->unref();
}
SubstringData const& substring_data() const
{
return *reinterpret_cast<SubstringData const*>(m_bytes_or_substring_data);
}
// NOTE: There is no guarantee about null-termination.
ReadonlyBytes bytes() const
{
if (m_substring) {
auto const& data = substring_data();
return data.superstring->bytes().slice(data.start_offset, m_byte_count);
}
return { &m_bytes_or_substring_data[0], m_byte_count };
}
StringView bytes_as_string_view() const { return { bytes() }; }
bool operator==(StringData const& other) const
{
return bytes_as_string_view() == other.bytes_as_string_view();
}
unsigned hash() const
{
if (!m_has_hash)
compute_hash();
return m_hash;
}
bool is_fly_string() const { return m_is_fly_string; }
void set_fly_string(bool is_fly_string) const { m_is_fly_string = is_fly_string; }
size_t byte_count() const { return m_byte_count; }
private:
static constexpr size_t allocation_size_for_string_data(size_t length)
{
return sizeof(StringData) + (sizeof(char) * length);
}
explicit StringData(size_t byte_count)
: m_byte_count(byte_count)
{
}
StringData(StringData const& superstring, size_t start, size_t byte_count)
: m_byte_count(byte_count)
, m_substring(true)
{
auto& data = const_cast<SubstringData&>(substring_data());
data.start_offset = start;
data.superstring = &superstring;
superstring.ref();
}
void compute_hash() const
{
auto bytes = this->bytes();
if (bytes.size() == 0)
m_hash = 0;
else
m_hash = string_hash(reinterpret_cast<char const*>(bytes.data()), bytes.size());
m_has_hash = true;
}
u32 m_byte_count { 0 };
mutable unsigned m_hash { 0 };
mutable bool m_has_hash { false };
bool m_substring { false };
mutable bool m_is_fly_string { false };
alignas(SubstringData) u8 m_bytes_or_substring_data[0];
};
ReadonlyBytes ShortString::bytes() const ReadonlyBytes ShortString::bytes() const
{ {
return { storage, byte_count() }; return { storage, byte_count() };

139
AK/StringData.h Normal file
View file

@ -0,0 +1,139 @@
/*
* Copyright (c) 2023, Dan Klishch <danilklishch@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/RefCounted.h>
#include <AK/kmalloc.h>
namespace AK::Detail {
class StringData final : public RefCounted<StringData> {
public:
static ErrorOr<NonnullRefPtr<StringData>> create_uninitialized(size_t byte_count, u8*& buffer)
{
VERIFY(byte_count);
void* slot = malloc(allocation_size_for_string_data(byte_count));
if (!slot) {
return Error::from_errno(ENOMEM);
}
auto new_string_data = adopt_ref(*new (slot) StringData(byte_count));
buffer = const_cast<u8*>(new_string_data->bytes().data());
return new_string_data;
}
static ErrorOr<NonnullRefPtr<StringData>> create_substring(StringData const& superstring, size_t start, size_t byte_count)
{
// Strings of MAX_SHORT_STRING_BYTE_COUNT bytes or less should be handled by the String short string optimization.
VERIFY(byte_count > MAX_SHORT_STRING_BYTE_COUNT);
void* slot = malloc(sizeof(StringData) + sizeof(StringData::SubstringData));
if (!slot) {
return Error::from_errno(ENOMEM);
}
return adopt_ref(*new (slot) StringData(superstring, start, byte_count));
}
struct SubstringData {
StringData const* superstring { nullptr };
u32 start_offset { 0 };
};
void operator delete(void* ptr)
{
free(ptr);
}
void unref() const
{
if (m_is_fly_string && m_ref_count == 2) {
m_is_fly_string = false; // Otherwise unref from did_destroy_fly_string_data will cause infinite recursion.
FlyString::did_destroy_fly_string_data({}, *this);
}
RefCounted::unref();
}
~StringData()
{
if (m_substring)
substring_data().superstring->unref();
}
SubstringData const& substring_data() const
{
return *reinterpret_cast<SubstringData const*>(m_bytes_or_substring_data);
}
// NOTE: There is no guarantee about null-termination.
ReadonlyBytes bytes() const
{
if (m_substring) {
auto const& data = substring_data();
return data.superstring->bytes().slice(data.start_offset, m_byte_count);
}
return { &m_bytes_or_substring_data[0], m_byte_count };
}
StringView bytes_as_string_view() const { return { bytes() }; }
bool operator==(StringData const& other) const
{
return bytes_as_string_view() == other.bytes_as_string_view();
}
unsigned hash() const
{
if (!m_has_hash)
compute_hash();
return m_hash;
}
bool is_fly_string() const { return m_is_fly_string; }
void set_fly_string(bool is_fly_string) const { m_is_fly_string = is_fly_string; }
size_t byte_count() const { return m_byte_count; }
private:
static constexpr size_t allocation_size_for_string_data(size_t length)
{
return sizeof(StringData) + (sizeof(char) * length);
}
explicit StringData(size_t byte_count)
: m_byte_count(byte_count)
{
}
StringData(StringData const& superstring, size_t start, size_t byte_count)
: m_byte_count(byte_count)
, m_substring(true)
{
auto& data = const_cast<SubstringData&>(substring_data());
data.start_offset = start;
data.superstring = &superstring;
superstring.ref();
}
void compute_hash() const
{
auto bytes = this->bytes();
if (bytes.size() == 0)
m_hash = 0;
else
m_hash = string_hash(reinterpret_cast<char const*>(bytes.data()), bytes.size());
m_has_hash = true;
}
u32 m_byte_count { 0 };
mutable unsigned m_hash { 0 };
mutable bool m_has_hash { false };
bool m_substring { false };
mutable bool m_is_fly_string { false };
alignas(SubstringData) u8 m_bytes_or_substring_data[0];
};
}