GFileEnumerator

GFileEnumerator — Enumerated Files Routines

Properties

GFile * container Write / Construct Only

Types and Values

Object Hierarchy

    GObject
    ╰── GFileEnumerator

Includes

#include <gio/gio.h>

Description

GFileEnumerator allows you to operate on a set of GFiles, returning a GFileInfo structure for each file enumerated (e.g. g_file_enumerate_children() will return a GFileEnumerator for each of the children within a directory).

To get the next file's information from a GFileEnumerator, use g_file_enumerator_next_file() or its asynchronous version, g_file_enumerator_next_files_async(). Note that the asynchronous version will return a list of GFileInfos, whereas the synchronous will only return the next file in the enumerator.

The ordering of returned files is unspecified for non-Unix platforms; for more information, see g_dir_read_name(). On Unix, when operating on local files, returned files will be sorted by inode number. Effectively you can assume that the ordering of returned files will be stable between successive calls (and applications) assuming the directory is unchanged.

If your application needs a specific ordering, such as by name or modification time, you will have to implement that in your application code.

To close a GFileEnumerator, use g_file_enumerator_close(), or its asynchronous version, g_file_enumerator_close_async(). Once a GFileEnumerator is closed, no further actions may be performed on it, and it should be freed with g_object_unref().

Functions

g_file_enumerator_iterate ()

gboolean
g_file_enumerator_iterate (GFileEnumerator *direnum,
                           GFileInfo **out_info,
                           GFile **out_child,
                           GCancellable *cancellable,
                           GError **error);

This is a version of g_file_enumerator_next_file() that's easier to use correctly from C programs. With g_file_enumerator_next_file(), the gboolean return value signifies "end of iteration or error", which requires allocation of a temporary GError.

In contrast, with this function, a FALSE return from g_file_enumerator_iterate() *always* means "error". End of iteration is signaled by out_info or out_child being NULL.

Another crucial difference is that the references for out_info and out_child are owned by direnum (they are cached as hidden properties). You must not unref them in your own code. This makes memory management significantly easier for C code in combination with loops.

Finally, this function optionally allows retrieving a GFile as well.

You must specify at least one of out_info or out_child .

The code pattern for correctly using g_file_enumerator_iterate() from C is:

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direnum = g_file_enumerate_children (file, ...);
while (TRUE)
  {
    GFileInfo *info;
    if (!g_file_enumerator_iterate (direnum, &info, NULL, cancellable, error))
      goto out;
    if (!info)
      break;
    ... do stuff with "info"; do not unref it! ...
  }

out:
  g_object_unref (direnum); // Note: frees the last @info

Parameters

direnum

an open GFileEnumerator

 

out_info

Output location for the next GFileInfo, or NULL.

[out][transfer none][optional]

out_child

Output location for the next GFile, or NULL.

[out][transfer none][optional]

cancellable

a GCancellable

 

error

a GError

 

Since: 2.44


g_file_enumerator_next_file ()

GFileInfo *
g_file_enumerator_next_file (GFileEnumerator *enumerator,
                             GCancellable *cancellable,
                             GError **error);

Returns information for the next file in the enumerated object. Will block until the information is available. The GFileInfo returned from this function will contain attributes that match the attribute string that was passed when the GFileEnumerator was created.

See the documentation of GFileEnumerator for information about the order of returned files.

On error, returns NULL and sets error to the error. If the enumerator is at the end, NULL will be returned and error will be unset.

Parameters

enumerator

a GFileEnumerator.

 

cancellable

optional GCancellable object, NULL to ignore.

[nullable]

error

location to store the error occurring, or NULL to ignore

 

Returns

A GFileInfo or NULL on error or end of enumerator. Free the returned object with g_object_unref() when no longer needed.

[nullable][transfer full]


g_file_enumerator_close ()

gboolean
g_file_enumerator_close (GFileEnumerator *enumerator,
                         GCancellable *cancellable,
                         GError **error);

Releases all resources used by this enumerator, making the enumerator return G_IO_ERROR_CLOSED on all calls.

This will be automatically called when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.

Parameters

enumerator

a GFileEnumerator.

 

cancellable

optional GCancellable object, NULL to ignore.

[nullable]

error

location to store the error occurring, or NULL to ignore

 

Returns

TRUE on success or FALSE on error.


g_file_enumerator_next_files_async ()

void
g_file_enumerator_next_files_async (GFileEnumerator *enumerator,
                                    int num_files,
                                    int io_priority,
                                    GCancellable *cancellable,
                                    GAsyncReadyCallback callback,
                                    gpointer user_data);

Request information for a number of files from the enumerator asynchronously. When all i/o for the operation is finished the callback will be called with the requested information.

See the documentation of GFileEnumerator for information about the order of returned files.

The callback can be called with less than num_files files in case of error or at the end of the enumerator. In case of a partial error the callback will be called with any succeeding items and no error, and on the next request the error will be reported. If a request is cancelled the callback will be called with G_IO_ERROR_CANCELLED.

During an async request no other sync and async calls are allowed, and will result in G_IO_ERROR_PENDING errors.

Any outstanding i/o request with higher priority (lower numerical value) will be executed before an outstanding request with lower priority. Default priority is G_PRIORITY_DEFAULT.

Parameters

enumerator

a GFileEnumerator.

 

num_files

the number of file info objects to request

 

io_priority

the I/O priority of the request

 

cancellable

optional GCancellable object, NULL to ignore.

[nullable]

callback

a GAsyncReadyCallback to call when the request is satisfied.

[scope async]

user_data

the data to pass to callback function.

[closure]

g_file_enumerator_next_files_finish ()

GList *
g_file_enumerator_next_files_finish (GFileEnumerator *enumerator,
                                     GAsyncResult *result,
                                     GError **error);

Finishes the asynchronous operation started with g_file_enumerator_next_files_async().

Parameters

enumerator

a GFileEnumerator.

 

result

a GAsyncResult.

 

error

a GError location to store the error occurring, or NULL to ignore.

 

Returns

a GList of GFileInfos. You must free the list with g_list_free() and unref the infos with g_object_unref() when you're done with them.

[transfer full][element-type Gio.FileInfo]


g_file_enumerator_close_async ()

void
g_file_enumerator_close_async (GFileEnumerator *enumerator,
                               int io_priority,
                               GCancellable *cancellable,
                               GAsyncReadyCallback callback,
                               gpointer user_data);

Asynchronously closes the file enumerator.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be returned in g_file_enumerator_close_finish().

Parameters

enumerator

a GFileEnumerator.

 

io_priority

the I/O priority of the request

 

cancellable

optional GCancellable object, NULL to ignore.

[nullable]

callback

a GAsyncReadyCallback to call when the request is satisfied.

[scope async]

user_data

the data to pass to callback function.

[closure]

g_file_enumerator_close_finish ()

gboolean
g_file_enumerator_close_finish (GFileEnumerator *enumerator,
                                GAsyncResult *result,
                                GError **error);

Finishes closing a file enumerator, started from g_file_enumerator_close_async().

If the file enumerator was already closed when g_file_enumerator_close_async() was called, then this function will report G_IO_ERROR_CLOSED in error , and return FALSE. If the file enumerator had pending operation when the close operation was started, then this function will report G_IO_ERROR_PENDING, and return FALSE. If cancellable was not NULL, then the operation may have been cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be set, and FALSE will be returned.

Parameters

enumerator

a GFileEnumerator.

 

result

a GAsyncResult.

 

error

a GError location to store the error occurring, or NULL to ignore.

 

Returns

TRUE if the close operation has finished successfully.


g_file_enumerator_is_closed ()

gboolean
g_file_enumerator_is_closed (GFileEnumerator *enumerator);

Checks if the file enumerator has been closed.

Parameters

enumerator

a GFileEnumerator.

 

Returns

TRUE if the enumerator is closed.


g_file_enumerator_has_pending ()

gboolean
g_file_enumerator_has_pending (GFileEnumerator *enumerator);

Checks if the file enumerator has pending operations.

Parameters

enumerator

a GFileEnumerator.

 

Returns

TRUE if the enumerator has pending operations.


g_file_enumerator_set_pending ()

void
g_file_enumerator_set_pending (GFileEnumerator *enumerator,
                               gboolean pending);

Sets the file enumerator as having pending operations.

Parameters

enumerator

a GFileEnumerator.

 

pending

a boolean value.

 

g_file_enumerator_get_container ()

GFile *
g_file_enumerator_get_container (GFileEnumerator *enumerator);

Get the GFile container which is being enumerated.

Parameters

enumerator

a GFileEnumerator

 

Returns

the GFile which is being enumerated.

[transfer none]

Since: 2.18


g_file_enumerator_get_child ()

GFile *
g_file_enumerator_get_child (GFileEnumerator *enumerator,
                             GFileInfo *info);

Return a new GFile which refers to the file named by info in the source directory of enumerator . This function is primarily intended to be used inside loops with g_file_enumerator_next_file().

This is a convenience method that's equivalent to:

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gchar *name = g_file_info_get_name (info);
GFile *child = g_file_get_child (g_file_enumerator_get_container (enumr),
                                 name);

Parameters

enumerator

a GFileEnumerator

 

info

a GFileInfo gotten from g_file_enumerator_next_file() or the async equivalents.

 

Returns

a GFile for the GFileInfo passed it.

[transfer full]

Since: 2.36

Types and Values

GFileEnumerator

typedef struct _GFileEnumerator GFileEnumerator;

A per matched file iterator.

Property Details

The “container” property

  “container”                GFile *

The container that is being enumerated.

Flags: Write / Construct Only