banan-os/kernel/kernel/FS/Pipe.cpp

86 lines
1.9 KiB
C++

#include <kernel/FS/Pipe.h>
#include <kernel/Lock/LockGuard.h>
#include <kernel/Thread.h>
#include <kernel/Timer/Timer.h>
namespace Kernel
{
BAN::ErrorOr<BAN::RefPtr<Inode>> Pipe::create(const Credentials& credentials)
{
Pipe* pipe = new Pipe(credentials);
if (pipe == nullptr)
return BAN::Error::from_errno(ENOMEM);
return BAN::RefPtr<Inode>::adopt(pipe);
}
Pipe::Pipe(const Credentials& credentials)
: m_uid(credentials.euid())
, m_gid(credentials.egid())
{
timespec current_time = SystemTimer::get().real_time();
m_atime = current_time;
m_mtime = current_time;
m_ctime = current_time;
}
void Pipe::clone_writing()
{
LockGuard _(m_mutex);
ASSERT(m_writing_count > 0);
m_writing_count++;
}
void Pipe::close_writing()
{
LockGuard _(m_mutex);
ASSERT(m_writing_count > 0);
m_writing_count--;
if (m_writing_count == 0)
m_semaphore.unblock();
}
BAN::ErrorOr<size_t> Pipe::read_impl(off_t, BAN::ByteSpan buffer)
{
LockGuard _(m_mutex);
while (m_buffer.empty())
{
if (m_writing_count == 0)
return 0;
LockFreeGuard lock_free(m_mutex);
TRY(Thread::current().block_or_eintr_indefinite(m_semaphore));
}
size_t to_copy = BAN::Math::min<size_t>(buffer.size(), m_buffer.size());
memcpy(buffer.data(), m_buffer.data(), to_copy);
memmove(m_buffer.data(), m_buffer.data() + to_copy, m_buffer.size() - to_copy);
MUST(m_buffer.resize(m_buffer.size() - to_copy));
m_atime = SystemTimer::get().real_time();
m_semaphore.unblock();
return to_copy;
}
BAN::ErrorOr<size_t> Pipe::write_impl(off_t, BAN::ConstByteSpan buffer)
{
LockGuard _(m_mutex);
size_t old_size = m_buffer.size();
TRY(m_buffer.resize(old_size + buffer.size()));
memcpy(m_buffer.data() + old_size, buffer.data(), buffer.size());
timespec current_time = SystemTimer::get().real_time();
m_mtime = current_time;
m_ctime = current_time;
m_semaphore.unblock();
return buffer.size();
}
}