direnum.c File Reference

Directory enumerator functions. More...

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "est_ops.h"
#include "direnum.h"
#include "warnings.h"
#include "global.h"
#include "helper.h"
#include <linux/types.h>
#include <linux/unistd.h>

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Defines
#define	HAVE_GETDENTS64 1
	If the system fulfills all necessary checks to use getdents(), this macro is set.
#define	FREE_SPACE (4096)
	The amount of memory that should be allocated for directory reading.
Typedefs
typedef int	dir__handle
	The type of handle.
typedef struct dirent64	fsvs_dirent
	A compatibility structure.
Functions
int	dir__start_enum (dir__handle dh, char path)
	Starts enumeration of the given path.
int	dir__enum (dir__handle dh, fsvs_dirent *dirp, unsigned int count)
	The enumeration function.
int	dir__close (dir__handle dh)
	Simply closes the handle dh.
int	dir__get_dir_size (dir__handle dh, struct sstat_t *st)
	How to get the length of a directory (in bytes), from a handle dh, into st->size.
int	dir___f_sort_by_inodePP (struct estat a, struct estat b)
	Compares two struct estat pointers by device/inode.
int	dir___f_sort_by_inode (struct estat a, struct estat b)
	Compares the data inside two struct estat pointers to pointers by device/inode.
int	dir___f_sort_by_nameCC (const void a, const void b)
	Compares two names/strings.
int	dir___f_sort_by_name (const void a, const void b)
	Compares the data inside two struct estat pointers to pointers by name.
int	dir___f_sort_by_nameCS (const void a, const void b)
	Compares a pointer to name (string) with a struct estat pointer to pointer.
int	dir__sortbyname (struct estat *sts)
	-.
int	dir__sortbyinode (struct estat *sts)
	-.
int	dir__enumerator (struct estat *this, int est_count, int give_by_name)
	-.

Detailed Description

Directory enumerator functions.

Definition in file direnum.c.

Define Documentation

#define FREE_SPACE (4096)

The amount of memory that should be allocated for directory reading.

This value should be bigger (or at least equal) than the number of bytes returned by getdents(). For the compatibility layer it's more or less the maximum filename length plus the inode and record length lengths.

This many bytes more will also be allocated for the filenames in a directory; if we get this close to the end of the buffer, the memory area will be reallocated.

Definition at line 226 of file direnum.c.

Referenced by dir__enumerator().

Function Documentation

int dir___f_sort_by_inode	(	struct estat **	a,
		struct estat **	b
	)

Compares the data inside two struct estat pointers to pointers by device/inode.

Returns:: +2, +1, 0, -1, -2, suitable for qsort().

Definition at line 252 of file direnum.c.

References dir___f_sort_by_inodePP().

Referenced by dir__sortbyinode(), ops__find_entry_byinode(), waa___find_position(), and waa__output_tree().

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int dir___f_sort_by_inodePP	(	struct estat *	a,
		struct estat *	b
	)

Compares two struct estat pointers by device/inode.

Returns:: +2, +1, 0, -1, -2, suitable for qsort().

That is now an inline function; but without force gcc doesn't inline it on 32bit, because of the size (64bit compares, 0x6b bytes). [ __attribute__((always_inline)) in declaration].

Definition at line 235 of file direnum.c.

References sstat_t::dev, sstat_t::ino, and estat::st.

Referenced by dir___f_sort_by_inode(), and ign__is_ignore().

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int dir___f_sort_by_name	(	const void *	a,
		const void *	b
	)

Compares the data inside two struct estat pointers to pointers by name.

Returns:: +2, +1, 0, -1, -2, suitable for qsort().

Definition at line 271 of file direnum.c.

References dir___f_sort_by_nameCC().

Referenced by dir__sortbyname(), and ops__correlate_dirs().

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int dir___f_sort_by_nameCC	(	const void *	a,
		const void *	b
	)			`[inline]`

Compares two names/strings.

Used for type checking cleanliness. 'C' as for 'Const'.

Returns:: +2, +1, 0, -1, -2, suitable for qsort().

Definition at line 262 of file direnum.c.

Referenced by dir___f_sort_by_name(), and dir___f_sort_by_nameCS().

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int dir___f_sort_by_nameCS	(	const void *	a,
		const void *	b
	)

Compares a pointer to name (string) with a struct estat pointer to pointer.

Returns:: +2, +1, 0, -1, -2, suitable for qsort().

Definition at line 283 of file direnum.c.

References dir___f_sort_by_nameCC().

Referenced by ops__find_entry_byname().

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int dir__enumerator	(	struct estat *	this,
		int	est_count,
		int	give_by_name
	)

-.

This function reads a directory into a self-allocated memory area.

The entries are sorted by inode number and stat()ed.

Parameters:

	this	a pointer to this directory's stat - for estimating the number of entries. Only this->st.st_size is used for that - it may have to be zeroed before calling.
	est_count	is used to give an approximate number of entries, to avoid many realloc()s.
	give_by_name	simply tells whether the ->by_name array should be created, too.

The result is written back into the sub-entry array in this.

To avoid reallocating (and copying!) large amounts of memory, this function fills some arrays from the directory, then allocates the needed space, sorts the data (see note below) and adds all other data. See sts_array, names and inode_numbers.

Note:: Sorting by inode number brings about 30% faster lookup times on my test environment (8 to 5 seconds) on an empty cache. Once the cache is filled, it won't make a difference.