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#include <AK/HashTable.h>
#include <AK/StdLibExtras.h>
#include <Kernel/FileSystem/FIFO.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Lock.h>
#include <Kernel/Process.h>
#include <Kernel/Thread.h>
//#define FIFO_DEBUG
Lockable<HashTable<FIFO*>>& all_fifos()
{
static Lockable<HashTable<FIFO*>>* s_table;
if (!s_table)
s_table = new Lockable<HashTable<FIFO*>>;
return *s_table;
}
RetainPtr<FIFO> FIFO::from_fifo_id(dword id)
{
auto* ptr = reinterpret_cast<FIFO*>(id);
LOCKER(all_fifos().lock());
if (auto it = all_fifos().resource().find(ptr); it == all_fifos().resource().end())
return nullptr;
return ptr;
}
Retained<FIFO> FIFO::create(uid_t uid)
{
return adopt(*new FIFO(uid));
}
Retained<FileDescription> FIFO::open_direction(FIFO::Direction direction)
{
auto description = FileDescription::create(this);
attach(direction);
description->set_fifo_direction({}, direction);
return description;
}
FIFO::FIFO(uid_t uid)
: m_uid(uid)
{
LOCKER(all_fifos().lock());
all_fifos().resource().set(this);
}
FIFO::~FIFO()
{
LOCKER(all_fifos().lock());
all_fifos().resource().remove(this);
}
void FIFO::attach(Direction direction)
{
if (direction == Direction::Reader) {
++m_readers;
#ifdef FIFO_DEBUG
kprintf("open reader (%u)\n", m_readers);
#endif
} else if (direction == Direction::Writer) {
++m_writers;
#ifdef FIFO_DEBUG
kprintf("open writer (%u)\n", m_writers);
#endif
}
}
void FIFO::detach(Direction direction)
{
if (direction == Direction::Reader) {
#ifdef FIFO_DEBUG
kprintf("close reader (%u - 1)\n", m_readers);
#endif
ASSERT(m_readers);
--m_readers;
} else if (direction == Direction::Writer) {
#ifdef FIFO_DEBUG
kprintf("close writer (%u - 1)\n", m_writers);
#endif
ASSERT(m_writers);
--m_writers;
}
}
bool FIFO::can_read(FileDescription&) const
{
return !m_buffer.is_empty() || !m_writers;
}
bool FIFO::can_write(FileDescription&) const
{
return m_buffer.bytes_in_write_buffer() < 4096 || !m_readers;
}
ssize_t FIFO::read(FileDescription&, byte* buffer, ssize_t size)
{
if (!m_writers && m_buffer.is_empty())
return 0;
#ifdef FIFO_DEBUG
dbgprintf("fifo: read(%u)\n", size);
#endif
ssize_t nread = m_buffer.read(buffer, size);
#ifdef FIFO_DEBUG
dbgprintf(" -> read (%c) %u\n", buffer[0], nread);
#endif
return nread;
}
ssize_t FIFO::write(FileDescription&, const byte* buffer, ssize_t size)
{
if (!m_readers) {
current->process().send_signal(SIGPIPE, ¤t->process());
return -EPIPE;
}
#ifdef FIFO_DEBUG
dbgprintf("fifo: write(%p, %u)\n", buffer, size);
#endif
return m_buffer.write(buffer, size);
}
String FIFO::absolute_path(const FileDescription&) const
{
return String::format("fifo:%u", this);
}
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