FileEnumerator#

class FileEnumerator(**properties: Any)#

Superclasses: Object

GFileEnumerator allows you to operate on a set of File objects, returning a FileInfo structure for each file enumerated (e.g. 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 next_file or its asynchronous version, next_files_async. Note that the asynchronous version will return a list of FileInfo objects, 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 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 close, or its asynchronous version, close_async. Once a GFileEnumerator is closed, no further actions may be performed on it, and it should be freed with unref.

Methods#

class FileEnumerator
close(cancellable: Cancellable | None = None) → bool#

Releases all resources used by this enumerator, making the enumerator return 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:

cancellable – optional Cancellable object, None to ignore.

close_async(io_priority: int, cancellable: Cancellable | None = None, callback: Callable[[...], None] | None = None, *user_data: Any) → None#

Asynchronously closes the file enumerator.

If cancellable is not None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error CANCELLED will be returned in close_finish().

Parameters:

  • io_priority – the I/O priority of the request

  • cancellable – optional Cancellable object, None to ignore.

  • callback – a AsyncReadyCallback to call when the request is satisfied

  • user_data – the data to pass to callback function

close_finish(result: AsyncResult) → bool#

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

If the file enumerator was already closed when close_async() was called, then this function will report CLOSED in error, and return False. If the file enumerator had pending operation when the close operation was started, then this function will report PENDING, and return False. If cancellable was not None, then the operation may have been cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error CANCELLED will be set, and False will be returned.

Parameters:

result – a AsyncResult.

get_child(info: FileInfo) → File#

Return a new File 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 next_file().

To use this, FILE_ATTRIBUTE_STANDARD_NAME must have been listed in the attributes list used when creating the FileEnumerator.

This is a convenience method that’s equivalent to:

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

Added in version 2.36.

Parameters:

info – a FileInfo gotten from next_file() or the async equivalents.

get_container() → File#

Get the File container which is being enumerated.

Added in version 2.18.

has_pending() → bool#

Checks if the file enumerator has pending operations.

is_closed() → bool#

Checks if the file enumerator has been closed.

iterate(cancellable: Cancellable | None = None) → tuple[bool, FileInfo, File]#

This is a version of next_file() that’s easier to use correctly from C programs. With next_file(), the gboolean return value signifies “end of iteration or error”, which requires allocation of a temporary Error.

In contrast, with this function, a False return from iterate() always means “error”. End of iteration is signaled by out_info or out_child being None.

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 File as well.

You must specify at least one of out_info or out_child.

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

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``

Added in version 2.44.

Parameters:

cancellable – a Cancellable

next()#
next_file(cancellable: Cancellable | None = None) → FileInfo | None#

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

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

On error, returns None and sets error to the error. If the enumerator is at the end, None will be returned and error will be unset.

Parameters:

cancellable – optional Cancellable object, None to ignore.

next_files_async(num_files: int, io_priority: int, cancellable: Cancellable | None = None, callback: Callable[[...], None] | None = None, *user_data: Any) → None#

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 FileEnumerator for information about the order of returned files.

Once the end of the enumerator is reached, or if an error occurs, the callback will be called with an empty list. In this case, the previous call to next_files_async() will typically have returned fewer than num_files items.

If a request is cancelled the callback will be called with CANCELLED.

This leads to the following pseudo-code usage:

g_autoptr(GFile) dir = get_directory ();
g_autoptr(GFileEnumerator) enumerator = NULL;
g_autolist(GFileInfo) files = NULL;
g_autoptr(GError) local_error = NULL;

enumerator = yield g_file_enumerate_children_async (dir,
                                                    G_FILE_ATTRIBUTE_STANDARD_NAME ","
                                                    G_FILE_ATTRIBUTE_STANDARD_TYPE,
                                                    G_FILE_QUERY_INFO_NONE,
                                                    G_PRIORITY_DEFAULT,
                                                    cancellable,
                                                    …,
                                                    &local_error);
if (enumerator == NULL)
  g_error ("Error enumerating: ``%s``", local_error->message);

// Loop until no files are returned, either because the end of the enumerator
// has been reached, or an error was returned.
do
  {
    files = yield g_file_enumerator_next_files_async (enumerator,
                                                      5,  // number of files to request
                                                      G_PRIORITY_DEFAULT,
                                                      cancellable,
                                                      …,
                                                      &local_error);

    // Process the returned files, but don’t assume that exactly 5 were returned.
    for (GList *l = files; l != NULL; l = l->next)
      {
        GFileInfo *info = l->data;
        handle_file_info (info);
      }
  }
while (files != NULL);

if (local_error != NULL &&
    !g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
  g_error ("Error while enumerating: ``%s``", local_error->message);

During an async request no other sync and async calls are allowed, and will result in 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:

  • num_files – the number of file info objects to request

  • io_priority –

    the I/O priority of the request

  • cancellable – optional Cancellable object, None to ignore.

  • callback – a AsyncReadyCallback to call when the request is satisfied

  • user_data – the data to pass to callback function

next_files_finish(result: AsyncResult) → list[FileInfo]#

Finishes the asynchronous operation started with next_files_async().

Parameters:

result – a AsyncResult.

set_pending(pending: bool) → None#

Sets the file enumerator as having pending operations.

Parameters:

pending – a boolean value.

Properties#

class FileEnumerator
props.container: File#

The type of the None singleton.

Virtual Methods#

class FileEnumerator
do_close_async(io_priority: int, cancellable: Cancellable | None = None, callback: Callable[[...], None] | None = None, *user_data: Any) → None#

Asynchronously closes the file enumerator.

If cancellable is not None, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error CANCELLED will be returned in close_finish().

Parameters:

  • io_priority –

    the I/O priority of the request

  • cancellable – optional Cancellable object, None to ignore.

  • callback – a AsyncReadyCallback to call when the request is satisfied

  • user_data – the data to pass to callback function

do_close_finish(result: AsyncResult) → bool#

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

If the file enumerator was already closed when close_async() was called, then this function will report CLOSED in error, and return False. If the file enumerator had pending operation when the close operation was started, then this function will report PENDING, and return False. If cancellable was not None, then the operation may have been cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error CANCELLED will be set, and False will be returned.

Parameters:

result – a AsyncResult.

do_close_fn(cancellable: Cancellable | None = None) → bool#

The type of the None singleton.

Parameters:

cancellable

do_next_file(cancellable: Cancellable | None = None) → FileInfo | None#

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

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

On error, returns None and sets error to the error. If the enumerator is at the end, None will be returned and error will be unset.

Parameters:

cancellable – optional Cancellable object, None to ignore.

do_next_files_async(num_files: int, io_priority: int, cancellable: Cancellable | None = None, callback: Callable[[...], None] | None = None, *user_data: Any) → None#

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 FileEnumerator for information about the order of returned files.

Once the end of the enumerator is reached, or if an error occurs, the callback will be called with an empty list. In this case, the previous call to next_files_async() will typically have returned fewer than num_files items.

If a request is cancelled the callback will be called with CANCELLED.

This leads to the following pseudo-code usage:

g_autoptr(GFile) dir = get_directory ();
g_autoptr(GFileEnumerator) enumerator = NULL;
g_autolist(GFileInfo) files = NULL;
g_autoptr(GError) local_error = NULL;

enumerator = yield g_file_enumerate_children_async (dir,
                                                    G_FILE_ATTRIBUTE_STANDARD_NAME ","
                                                    G_FILE_ATTRIBUTE_STANDARD_TYPE,
                                                    G_FILE_QUERY_INFO_NONE,
                                                    G_PRIORITY_DEFAULT,
                                                    cancellable,
                                                    …,
                                                    &local_error);
if (enumerator == NULL)
  g_error ("Error enumerating: ``%s``", local_error->message);

// Loop until no files are returned, either because the end of the enumerator
// has been reached, or an error was returned.
do
  {
    files = yield g_file_enumerator_next_files_async (enumerator,
                                                      5,  // number of files to request
                                                      G_PRIORITY_DEFAULT,
                                                      cancellable,
                                                      …,
                                                      &local_error);

    // Process the returned files, but don’t assume that exactly 5 were returned.
    for (GList *l = files; l != NULL; l = l->next)
      {
        GFileInfo *info = l->data;
        handle_file_info (info);
      }
  }
while (files != NULL);

if (local_error != NULL &&
    !g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
  g_error ("Error while enumerating: ``%s``", local_error->message);

During an async request no other sync and async calls are allowed, and will result in 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:

  • num_files – the number of file info objects to request

  • io_priority –

    the I/O priority of the request

  • cancellable – optional Cancellable object, None to ignore.

  • callback – a AsyncReadyCallback to call when the request is satisfied

  • user_data – the data to pass to callback function

do_next_files_finish(result: AsyncResult) → list[FileInfo]#

Finishes the asynchronous operation started with next_files_async().

Parameters:

result – a AsyncResult.

Fields#

class FileEnumerator
parent_instance#
priv#
On this page
Show Source