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/*
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Types.h>
#include <Kernel/FileSystem/ISO9660FS/Definitions.h>
#include <Kernel/FileSystem/ISO9660FS/DirectoryIterator.h>
#include <Kernel/Library/KBuffer.h>
namespace Kernel {
ISO9660DirectoryIterator::ISO9660DirectoryIterator(ISO9660FS& fs, ISO::DirectoryRecordHeader const& header)
: m_fs(fs)
, m_current_header(&header)
{
// FIXME: Panic or alternative method?
(void)read_directory_contents();
get_header();
}
ErrorOr<bool> ISO9660DirectoryIterator::next()
{
if (done())
return false;
dbgln_if(ISO9660_VERY_DEBUG, "next(): Called");
if (has_flag(m_current_header->file_flags, ISO::FileFlags::Directory)) {
dbgln_if(ISO9660_VERY_DEBUG, "next(): Recursing");
{
TRY(m_directory_stack.try_append(move(m_current_directory)));
}
dbgln_if(ISO9660_VERY_DEBUG, "next(): Pushed into directory stack");
TRY(read_directory_contents());
dbgln_if(ISO9660_VERY_DEBUG, "next(): Read directory contents");
m_current_directory.offset = 0;
get_header();
if (m_current_header->length == 0) {
// We have found an empty directory, let's continue with the
// next one.
if (!go_up())
return false;
} else {
// We cannot skip here, as this is the first record in this
// extent.
return true;
}
}
return skip();
}
bool ISO9660DirectoryIterator::skip()
{
VERIFY(m_current_directory.entry);
if (m_current_directory.offset >= m_current_directory.entry->length) {
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Was at last item already");
return false;
}
m_current_directory.offset += m_current_header->length;
get_header();
if (m_current_header->length == 0) {
// According to ECMA 119, if a logical block contains directory
// records, then the leftover bytes in the logical block are
// all zeros. So if our directory header has a length of 0,
// we're probably looking at padding.
//
// Of course, this doesn't mean we're done; it only means that there
// are no more directory entries in *this* logical block. If we
// have at least one more logical block of data length to go, we
// need to snap to the next logical block, because directory records
// cannot span multiple logical blocks.
u32 remaining_bytes = m_current_directory.entry->length - m_current_directory.offset;
if (remaining_bytes > m_fs.logical_block_size()) {
m_current_directory.offset += remaining_bytes % m_fs.logical_block_size();
get_header();
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Snapped to next logical block (succeeded)");
return true;
}
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Was at the last logical block, at padding now (offset {}, data length {})", m_current_directory.entry->length, m_current_directory.offset);
return false;
}
dbgln_if(ISO9660_VERY_DEBUG, "skip(): Skipped to next item");
return true;
}
bool ISO9660DirectoryIterator::go_up()
{
if (m_directory_stack.is_empty()) {
dbgln_if(ISO9660_VERY_DEBUG, "go_up(): Empty directory stack");
return false;
}
m_current_directory = m_directory_stack.take_last();
get_header();
dbgln_if(ISO9660_VERY_DEBUG, "go_up(): Went up a directory");
return true;
}
bool ISO9660DirectoryIterator::done() const
{
VERIFY(m_current_directory.entry);
auto result = m_directory_stack.is_empty() && m_current_directory.offset >= m_current_directory.entry->length;
dbgln_if(ISO9660_VERY_DEBUG, "done(): {}", result);
return result;
}
ErrorOr<void> ISO9660DirectoryIterator::read_directory_contents()
{
m_current_directory.entry = TRY(m_fs.directory_entry_for_record({}, m_current_header));
return {};
}
void ISO9660DirectoryIterator::get_header()
{
VERIFY(m_current_directory.entry);
if (!m_current_directory.entry->blocks)
return;
m_current_header = reinterpret_cast<ISO::DirectoryRecordHeader const*>(m_current_directory.entry->blocks->data() + m_current_directory.offset);
}
}
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