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/*
* Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Format.h>
#include <AK/QuickSort.h>
#include <AK/String.h>
#include <LibCore/IODevice.h>
#include <LibSQL/Heap.h>
#include <LibSQL/Serializer.h>
#include <sys/stat.h>
#include <sys/types.h>
namespace SQL {
Heap::Heap(String file_name)
{
set_name(move(file_name));
size_t file_size = 0;
struct stat stat_buffer;
if (stat(name().characters(), &stat_buffer) != 0) {
if (errno != ENOENT) {
perror("stat");
VERIFY_NOT_REACHED();
}
} else {
file_size = stat_buffer.st_size;
}
if (file_size > 0)
m_next_block = m_end_of_file = file_size / BLOCKSIZE;
auto file_or_error = Core::File::open(name(), Core::OpenMode::ReadWrite);
if (file_or_error.is_error()) {
warnln("Couldn't open '{}': {}", name(), file_or_error.error());
VERIFY_NOT_REACHED();
}
m_file = file_or_error.value();
if (file_size > 0)
read_zero_block();
else
initialize_zero_block();
dbgln_if(SQL_DEBUG, "Heap file {} opened. Size = {}", file_name, size());
}
Result<ByteBuffer, String> Heap::read_block(u32 block)
{
auto buffer_or_empty = m_write_ahead_log.get(block);
if (buffer_or_empty.has_value())
return buffer_or_empty.value();
VERIFY(block < m_next_block);
dbgln_if(SQL_DEBUG, "Read heap block {}", block);
if (!seek_block(block))
VERIFY_NOT_REACHED();
auto ret = m_file->read(BLOCKSIZE);
if (ret.is_empty())
return String("Could not read block");
dbgln_if(SQL_DEBUG, "{:02x} {:02x} {:02x} {:02x} {:02x} {:02x} {:02x} {:02x}",
*ret.offset_pointer(0), *ret.offset_pointer(1),
*ret.offset_pointer(2), *ret.offset_pointer(3),
*ret.offset_pointer(4), *ret.offset_pointer(5),
*ret.offset_pointer(6), *ret.offset_pointer(7));
return ret;
}
bool Heap::write_block(u32 block, ByteBuffer& buffer)
{
dbgln_if(SQL_DEBUG, "write_block({}): m_next_block {}", block, m_next_block);
VERIFY(block <= m_next_block);
if (!seek_block(block))
VERIFY_NOT_REACHED();
dbgln_if(SQL_DEBUG, "Write heap block {} size {}", block, buffer.size());
VERIFY(buffer.size() <= BLOCKSIZE);
auto sz = buffer.size();
if (sz < BLOCKSIZE) {
buffer.resize(BLOCKSIZE);
memset(buffer.offset_pointer((int)sz), 0, BLOCKSIZE - sz);
}
dbgln_if(SQL_DEBUG, "{:02x} {:02x} {:02x} {:02x} {:02x} {:02x} {:02x} {:02x}",
*buffer.offset_pointer(0), *buffer.offset_pointer(1),
*buffer.offset_pointer(2), *buffer.offset_pointer(3),
*buffer.offset_pointer(4), *buffer.offset_pointer(5),
*buffer.offset_pointer(6), *buffer.offset_pointer(7));
if (m_file->write(buffer.data(), (int)buffer.size())) {
if (block == m_end_of_file)
m_end_of_file++;
return true;
}
return false;
}
bool Heap::seek_block(u32 block)
{
if (block == m_end_of_file) {
off_t pos;
if (!m_file->seek(0, Core::SeekMode::FromEndPosition, &pos)) {
warnln("Could not seek block {} from file {}, which is at the end of the file", block, name());
warnln("FD: {} Position: {} error: {}", m_file->fd(), pos, m_file->error_string());
return false;
}
} else if (block > m_end_of_file) {
warnln("Seeking block {} of file {} which is beyond the end of the file", block, name());
return false;
} else {
if (!m_file->seek(block * BLOCKSIZE)) {
warnln("Could not seek block {} of file {}. The current size is {} blocks",
block, name(), m_end_of_file);
return false;
}
}
return true;
}
u32 Heap::new_record_pointer()
{
if (m_free_list) {
auto block_or_error = read_block(m_free_list);
if (block_or_error.is_error()) {
warnln("FREE LIST CORRUPTION");
VERIFY_NOT_REACHED();
}
auto new_pointer = m_free_list;
memcpy(&m_free_list, block_or_error.value().offset_pointer(0), sizeof(u32));
update_zero_block();
return new_pointer;
}
return m_next_block++;
}
void Heap::flush()
{
Vector<u32> blocks;
for (auto& wal_entry : m_write_ahead_log) {
blocks.append(wal_entry.key);
}
quick_sort(blocks);
for (auto& block : blocks) {
auto buffer_or_empty = m_write_ahead_log.get(block);
if (buffer_or_empty->is_empty()) {
VERIFY_NOT_REACHED();
}
dbgln_if(SQL_DEBUG, "Flushing block {} to {}", block, name());
write_block(block, buffer_or_empty.value());
}
m_write_ahead_log.clear();
dbgln_if(SQL_DEBUG, "WAL flushed. Heap size = {}", size());
}
constexpr static const char* FILE_ID = "SerenitySQL ";
constexpr static int VERSION_OFFSET = 12;
constexpr static int SCHEMAS_ROOT_OFFSET = 16;
constexpr static int TABLES_ROOT_OFFSET = 20;
constexpr static int TABLE_COLUMNS_ROOT_OFFSET = 24;
constexpr static int FREE_LIST_OFFSET = 28;
constexpr static int USER_VALUES_OFFSET = 32;
void Heap::read_zero_block()
{
char file_id[256];
auto bytes_or_error = read_block(0);
if (bytes_or_error.is_error())
VERIFY_NOT_REACHED();
auto buffer = bytes_or_error.value();
memcpy(file_id, buffer.offset_pointer(0), strlen(FILE_ID));
file_id[strlen(FILE_ID)] = 0;
if (strncmp(file_id, FILE_ID, strlen(FILE_ID)) != 0) {
warnln("Corrupt zero page in {}", name());
VERIFY_NOT_REACHED();
}
dbgln_if(SQL_DEBUG, "Read zero block from {}", name());
memcpy(&m_version, buffer.offset_pointer(VERSION_OFFSET), sizeof(u32));
dbgln_if(SQL_DEBUG, "Version: {}.{}", (m_version & 0xFFFF0000) >> 16, (m_version & 0x0000FFFF));
memcpy(&m_schemas_root, buffer.offset_pointer(SCHEMAS_ROOT_OFFSET), sizeof(u32));
dbgln_if(SQL_DEBUG, "Schemas root node: {}", m_tables_root);
memcpy(&m_tables_root, buffer.offset_pointer(TABLES_ROOT_OFFSET), sizeof(u32));
dbgln_if(SQL_DEBUG, "Tables root node: {}", m_tables_root);
memcpy(&m_table_columns_root, buffer.offset_pointer(TABLE_COLUMNS_ROOT_OFFSET), sizeof(u32));
dbgln_if(SQL_DEBUG, "Table columns root node: {}", m_table_columns_root);
memcpy(&m_free_list, buffer.offset_pointer(FREE_LIST_OFFSET), sizeof(u32));
dbgln_if(SQL_DEBUG, "Free list: {}", m_free_list);
memcpy(m_user_values.data(), buffer.offset_pointer(USER_VALUES_OFFSET), m_user_values.size() * sizeof(u32));
for (auto ix = 0u; ix < m_user_values.size(); ix++) {
if (m_user_values[ix]) {
dbgln_if(SQL_DEBUG, "User value {}: {}", ix, m_user_values[ix]);
}
}
}
void Heap::update_zero_block()
{
dbgln_if(SQL_DEBUG, "Write zero block to {}", name());
dbgln_if(SQL_DEBUG, "Version: {}.{}", (m_version & 0xFFFF0000) >> 16, (m_version & 0x0000FFFF));
dbgln_if(SQL_DEBUG, "Schemas root node: {}", m_schemas_root);
dbgln_if(SQL_DEBUG, "Tables root node: {}", m_tables_root);
dbgln_if(SQL_DEBUG, "Table Columns root node: {}", m_table_columns_root);
dbgln_if(SQL_DEBUG, "Free list: {}", m_free_list);
for (auto ix = 0u; ix < m_user_values.size(); ix++) {
if (m_user_values[ix]) {
dbgln_if(SQL_DEBUG, "User value {}: {}", ix, m_user_values[ix]);
}
}
auto buffer = ByteBuffer::create_zeroed(BLOCKSIZE);
buffer.overwrite(0, FILE_ID, strlen(FILE_ID));
buffer.overwrite(VERSION_OFFSET, &m_version, sizeof(u32));
buffer.overwrite(SCHEMAS_ROOT_OFFSET, &m_schemas_root, sizeof(u32));
buffer.overwrite(TABLES_ROOT_OFFSET, &m_tables_root, sizeof(u32));
buffer.overwrite(TABLE_COLUMNS_ROOT_OFFSET, &m_table_columns_root, sizeof(u32));
buffer.overwrite(FREE_LIST_OFFSET, &m_free_list, sizeof(u32));
buffer.overwrite(USER_VALUES_OFFSET, m_user_values.data(), m_user_values.size() * sizeof(u32));
add_to_wal(0, buffer);
}
void Heap::initialize_zero_block()
{
m_version = 0x00000001;
m_schemas_root = 0;
m_tables_root = 0;
m_table_columns_root = 0;
m_next_block = 1;
m_free_list = 0;
for (auto& user : m_user_values) {
user = 0u;
}
update_zero_block();
}
}
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