ladybird/Kernel/FileSystem/FileDescription.h
Andreas Kling 59ed235c85 Kernel: Implement O_DIRECT open() flag to bypass disk caches
Files opened with O_DIRECT will now bypass the disk cache in read/write
operations (though metadata operations will still hit the disk cache.)

This will allow us to test actual disk performance instead of testing
disk *cache* performance, if that's what we want. :^)

There's room for improvment here, we're very aggressively flushing any
dirty cache entries for the specific block before reading/writing that
block. This is done by walking the entire cache, which may be slow.
2019-11-05 19:35:12 +01:00

125 lines
3.3 KiB
C++

#pragma once
#include <AK/Badge.h>
#include <AK/ByteBuffer.h>
#include <AK/CircularQueue.h>
#include <AK/RefCounted.h>
#include <Kernel/FileSystem/FIFO.h>
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/FileSystem/InodeMetadata.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/KBuffer.h>
#include <Kernel/Net/Socket.h>
#include <Kernel/VM/VirtualAddress.h>
class File;
class TTY;
class MasterPTY;
class Process;
class Region;
class CharacterDevice;
class SharedMemory;
class FileDescription : public RefCounted<FileDescription> {
public:
static NonnullRefPtr<FileDescription> create(Custody&);
static NonnullRefPtr<FileDescription> create(File&);
~FileDescription();
int close();
off_t seek(off_t, int whence);
ssize_t read(u8*, ssize_t);
ssize_t write(const u8* data, ssize_t);
KResult fstat(stat&);
KResult fchmod(mode_t);
bool can_read() const;
bool can_write() const;
ssize_t get_dir_entries(u8* buffer, ssize_t);
ByteBuffer read_entire_file();
String absolute_path() const;
bool is_direct() const { return m_direct; }
bool is_directory() const { return m_is_directory; }
File& file() { return *m_file; }
const File& file() const { return *m_file; }
bool is_device() const;
bool is_tty() const;
const TTY* tty() const;
TTY* tty();
bool is_master_pty() const;
const MasterPTY* master_pty() const;
MasterPTY* master_pty();
InodeMetadata metadata() const;
Inode* inode() { return m_inode.ptr(); }
const Inode* inode() const { return m_inode.ptr(); }
Custody* custody() { return m_custody.ptr(); }
const Custody* custody() const { return m_custody.ptr(); }
KResultOr<Region*> mmap(Process&, VirtualAddress, size_t offset, size_t, int prot);
bool is_blocking() const { return m_is_blocking; }
void set_blocking(bool b) { m_is_blocking = b; }
bool should_append() const { return m_should_append; }
void set_should_append(bool s) { m_should_append = s; }
u32 file_flags() const { return m_file_flags; }
void set_file_flags(u32);
bool is_socket() const;
Socket* socket();
const Socket* socket() const;
bool is_fifo() const;
FIFO* fifo();
FIFO::Direction fifo_direction() { return m_fifo_direction; }
void set_fifo_direction(Badge<FIFO>, FIFO::Direction direction) { m_fifo_direction = direction; }
bool is_shared_memory() const;
SharedMemory* shared_memory();
const SharedMemory* shared_memory() const;
Optional<KBuffer>& generator_cache() { return m_generator_cache; }
void set_original_inode(Badge<VFS>, NonnullRefPtr<Inode>&& inode) { m_inode = move(inode); }
KResult truncate(off_t);
off_t offset() const { return m_current_offset; }
KResult chown(uid_t, gid_t);
private:
friend class VFS;
explicit FileDescription(File&);
FileDescription(FIFO&, FIFO::Direction);
RefPtr<Custody> m_custody;
RefPtr<Inode> m_inode;
NonnullRefPtr<File> m_file;
off_t m_current_offset { 0 };
Optional<KBuffer> m_generator_cache;
u32 m_file_flags { 0 };
bool m_is_blocking { true };
bool m_is_directory { false };
bool m_should_append { false };
bool m_direct { false };
FIFO::Direction m_fifo_direction { FIFO::Direction::Neither };
};