Kernel: Turn Process::FileDescriptionAndFlags into a proper class

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/2e2de125e51

Kernel/Process.cpp

@@ -488,7 +488,7 @@ RefPtr<FileDescription> Process::file_description(int fd) const
     if (fd < 0)
         return nullptr;
     if (static_cast<size_t>(fd) < m_fds.size())
-        return m_fds[fd].description.ptr();
+        return m_fds[fd].description();
     return nullptr;
 }
 
@@ -497,7 +497,7 @@ int Process::fd_flags(int fd) const
     if (fd < 0)
         return -1;
     if (static_cast<size_t>(fd) < m_fds.size())
-        return m_fds[fd].flags;
+        return m_fds[fd].flags();
     return -1;
 }
 
@@ -800,14 +800,14 @@ Thread* Process::create_kernel_thread(void (*entry)(), u32 priority, const Strin
 
 void Process::FileDescriptionAndFlags::clear()
 {
-    description = nullptr;
-    flags = 0;
+    m_description = nullptr;
+    m_flags = 0;
 }
 
-void Process::FileDescriptionAndFlags::set(NonnullRefPtr<FileDescription>&& d, u32 f)
+void Process::FileDescriptionAndFlags::set(NonnullRefPtr<FileDescription>&& description, u32 flags)
 {
-    description = move(d);
-    flags = f;
+    m_description = move(description);
+    m_flags = flags;
 }
 
 KBuffer Process::backtrace(ProcessInspectionHandle& handle) const

Kernel/Process.h

@@ -573,12 +573,22 @@ private:
 
     static const int m_max_open_file_descriptors { FD_SETSIZE };
 
-    struct FileDescriptionAndFlags {
-        operator bool() const { return !!description; }
+    class FileDescriptionAndFlags {
+    public:
+        operator bool() const { return !!m_description; }
+
+        FileDescription* description() { return m_description; }
+        const FileDescription* description() const { return m_description; }
+
+        u32 flags() const { return m_flags; }
+        void set_flags(u32 flags) { m_flags = flags; }
+
         void clear();
-        void set(NonnullRefPtr<FileDescription>&& d, u32 f = 0);
-        RefPtr<FileDescription> description;
-        u32 flags { 0 };
+        void set(NonnullRefPtr<FileDescription>&&, u32 flags = 0);
+
+    private:
+        RefPtr<FileDescription> m_description;
+        u32 m_flags { 0 };
     };
     Vector<FileDescriptionAndFlags> m_fds;
 

Kernel/Scheduler.cpp

@@ -221,13 +221,13 @@ bool Thread::SelectBlocker::should_unblock(Thread& thread, time_t now_sec, long
     for (int fd : m_select_read_fds) {
         if (!process.m_fds[fd])
             continue;
-        if (process.m_fds[fd].description->can_read())
+        if (process.m_fds[fd].description()->can_read())
             return true;
     }
     for (int fd : m_select_write_fds) {
         if (!process.m_fds[fd])
             continue;
-        if (process.m_fds[fd].description->can_write())
+        if (process.m_fds[fd].description()->can_write())
             return true;
     }
 

Kernel/Syscalls/execve.cpp

@@ -244,10 +244,10 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
     disown_all_shared_buffers();
 
     for (size_t i = 0; i < m_fds.size(); ++i) {
-        auto& daf = m_fds[i];
-        if (daf.description && daf.flags & FD_CLOEXEC) {
-            daf.description->close();
-            daf = {};
+        auto& description_and_flags = m_fds[i];
+        if (description_and_flags.description() && description_and_flags.flags() & FD_CLOEXEC) {
+            description_and_flags.description()->close();
+            description_and_flags = {};
         }
     }
 

Kernel/Syscalls/fcntl.cpp

@@ -52,9 +52,9 @@ int Process::sys$fcntl(int fd, int cmd, u32 arg)
         return new_fd;
     }
     case F_GETFD:
-        return m_fds[fd].flags;
+        return m_fds[fd].flags();
     case F_SETFD:
-        m_fds[fd].flags = arg;
+        m_fds[fd].set_flags(arg);
         break;
     case F_GETFL:
         return description->file_flags();

Kernel/Syscalls/pipe.cpp

@@ -46,12 +46,12 @@ int Process::sys$pipe(int pipefd[2], int flags)
 
     int reader_fd = alloc_fd();
     m_fds[reader_fd].set(fifo->open_direction(FIFO::Direction::Reader), fd_flags);
-    m_fds[reader_fd].description->set_readable(true);
+    m_fds[reader_fd].description()->set_readable(true);
     copy_to_user(&pipefd[0], &reader_fd);
 
     int writer_fd = alloc_fd();
     m_fds[writer_fd].set(fifo->open_direction(FIFO::Direction::Writer), fd_flags);
-    m_fds[writer_fd].description->set_writable(true);
+    m_fds[writer_fd].description()->set_writable(true);
     copy_to_user(&pipefd[1], &writer_fd);
 
     return 0;

Kernel/Syscalls/socket.cpp

@@ -115,7 +115,7 @@ int Process::sys$accept(int accepting_socket_fd, sockaddr* user_address, socklen
     // NOTE: The accepted socket inherits fd flags from the accepting socket.
     //       I'm not sure if this matches other systems but it makes sense to me.
     accepted_socket_description->set_blocking(accepting_socket_description->is_blocking());
-    m_fds[accepted_socket_fd].set(move(accepted_socket_description), m_fds[accepting_socket_fd].flags);
+    m_fds[accepted_socket_fd].set(move(accepted_socket_description), m_fds[accepting_socket_fd].flags());
 
     // NOTE: Moving this state to Completed is what causes connect() to unblock on the client side.
     accepted_socket->set_setup_state(Socket::SetupState::Completed);

Kernel/Syscalls/watch_file.cpp

@@ -53,7 +53,7 @@ int Process::sys$watch_file(const char* user_path, size_t path_length)
         return fd;
 
     m_fds[fd].set(FileDescription::create(*InodeWatcher::create(inode)));
-    m_fds[fd].description->set_readable(true);
+    m_fds[fd].description()->set_readable(true);
     return fd;
 }