cosmos::DirEntry Class Reference

A single directory entry as returned from DirStream::nextEntry(). More...

#include <DirEntry.hxx>

Public Types
enum class	DirPos : off_t
	strong type for representing directory stream positions More...
enum class	Type : unsigned char {   BLOCK_DEVICE = DT_BLK , CHAR_DEVICE = DT_CHR , DIRECTORY = DT_DIR , FIFO = DT_FIFO ,   SYMLINK = DT_LNK , REGULAR = DT_REG , UNIX_SOCKET = DT_SOCK , UNKNOWN = DT_UNKNOWN }
	Strong enum type expressing the dir entry file type. More...

Public Member Functions
auto	raw () const
Inode	inode () const
	Returns the inode of the directory entry.
DirPos	dirPos () const
	Returns the position of this entry in its associated DirStream object.
size_t	nameLength () const
	Returns the length of the directory entry name.
auto	type () const
	Returns the file type of this directory entry.
const char *	name () const
std::string_view	view () const
auto	isDotEntry () const
	Returns whether this entry is a "dot file entry" i.e. "." or "..".

Protected Member Functions
	DirEntry (const struct dirent *entry)

Protected Attributes
const struct dirent *	m_entry

Friends
class	DirStream
class	DirIterator

Detailed Description

A single directory entry as returned from DirStream::nextEntry().

The stored data is only valid as long as the DirStream object it was returned from is valid and as long as DirStream::nextEntry() isn't called again.

Definition at line 23 of file DirEntry.hxx.

Member Enumeration Documentation

DirPos

enum class cosmos::DirEntry::DirPos : off_t

strong

strong type for representing directory stream positions

This type is opaque and should never be interpreted by clients of this class. It is only obtained from tell() and passed back into seek().

Definition at line 35 of file DirEntry.hxx.

: off_t {};

Type

enum class cosmos::DirEntry::Type : unsigned char

strong

Strong enum type expressing the dir entry file type.

Definition at line 38 of file DirEntry.hxx.

                        : unsigned char {
                BLOCK_DEVICE = DT_BLK,
                CHAR_DEVICE  = DT_CHR,
                DIRECTORY    = DT_DIR,
                FIFO         = DT_FIFO,
                SYMLINK      = DT_LNK,
                REGULAR      = DT_REG,
                UNIX_SOCKET  = DT_SOCK,
                UNKNOWN      = DT_UNKNOWN
        };

Constructor & Destructor Documentation

DirEntry()

cosmos::DirEntry::DirEntry ( const struct dirent * entry )

inlineexplicitprotected

Definition at line 52 of file DirEntry.hxx.

                : m_entry{entry}
        {}

Member Function Documentation

dirPos()

DirPos cosmos::DirEntry::dirPos ( ) const

inline

Returns the position of this entry in its associated DirStream object.

This is the same as DirStream::tell(), it can be used in DirStream::seek() at a later time to return to the original position.

Definition at line 74 of file DirEntry.hxx.

{ return DirPos{m_entry->d_off}; }

inode()

Inode cosmos::DirEntry::inode ( ) const

inline

Returns the inode of the directory entry.

The inode is an opaque unique ID for the file system object on the file system it resides on.

Definition at line 66 of file DirEntry.hxx.

{ return Inode{m_entry->d_ino}; }

isDotEntry()

auto cosmos::DirEntry::isDotEntry ( ) const

inline

Returns whether this entry is a "dot file entry" i.e. "." or "..".

Definition at line 118 of file DirEntry.hxx.

                                {
                auto name = this->name();
                if (name[0] != '.')
                        return false;
                else if (name[1] == '\0')
                        return true;
                else if (name[1] != '.')
                        return false;
 
                return name[2] == '\0';
        }

name()

const char * cosmos::DirEntry::name ( ) const

inline

Definition at line 113 of file DirEntry.hxx.

{ return m_entry->d_name; }

nameLength()

size_t cosmos::DirEntry::nameLength ( ) const

inline

Returns the length of the directory entry name.

In pure POSIX the length of the name can only be determined using strlen(). This Linux specific information makes it easier and more efficient to determine the length.

The returned length is the number of characters in the entry name excluding the null terminator.

Definition at line 85 of file DirEntry.hxx.

                                  {
                // this actually involves padding, so look from a 8-byte
                // offset from the end forwards, still faster for long strings.
                auto len = m_entry->d_reclen - offsetof(struct dirent, d_name) - 1;
 
                len = len < 8 ? 0 : len - 8;
                auto endp = name() + len;
 
                for (size_t i = 0; i < 8; i++) {
                        if (*(endp++) == '\0')
                                return endp - name() - 1;
                }
 
                // unclear how this should ever happen
                return std::strlen(this->name());
        }

raw()

auto cosmos::DirEntry::raw ( ) const

inline

Definition at line 59 of file DirEntry.hxx.

{ return m_entry; }

type()

auto cosmos::DirEntry::type ( ) const

inline

Returns the file type of this directory entry.

For increased efficiency the file type of directory entries can be delivered directly with the DirStream readdir() data. This is not supported by all underlying file systems, however. Therefore be prepared to receive Type::UNKNOWN at all times in which case you will need to perform an explicit fstatat() or similar call to obtain the required information.

Definition at line 111 of file DirEntry.hxx.

{ return Type{m_entry->d_type}; }

view()

std::string_view cosmos::DirEntry::view ( ) const

inline

Definition at line 115 of file DirEntry.hxx.

{ return std::string_view{m_entry->d_name, nameLength()}; }

Friends And Related Symbol Documentation

DirIterator

friend class DirIterator

friend

Definition at line 25 of file DirEntry.hxx.

DirStream

friend class DirStream

friend

Definition at line 24 of file DirEntry.hxx.

Member Data Documentation

m_entry

const struct dirent* cosmos::DirEntry::m_entry

protected

Definition at line 132 of file DirEntry.hxx.

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The documentation for this class was generated from the following file:

• include/fs/DirEntry.hxx