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3ccd3b204c0619be34a8eae199b6464b6e45b4ac
glib/gio/gfileenumerator.c
Dan Winship 82d914d808 gio: add g_async_result_is_tagged() 
Rather than doing a two step first-check-the-GAsyncResult-subtype-then-
check-the-tag, add a GAsyncResult-level method so that you can do them
both at once, simplifying the code for "short-circuit" async return
values where the vmethod never gets called.

https://bugzilla.gnome.org/show_bug.cgi?id=661767
2012-07-10 10:49:20 -04:00

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23 KiB
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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2006-2007 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include "gfileenumerator.h"
#include "gfile.h"
#include "gioscheduler.h"
#include "gasyncresult.h"
#include "gasynchelper.h"
#include "gsimpleasyncresult.h"
#include "gioerror.h"
#include "glibintl.h"
/**
* SECTION:gfileenumerator
* @short_description: Enumerated Files Routines
* @include: gio/gio.h
*
* #GFileEnumerator allows you to operate on a set of #GFile<!-- -->s,
* 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 #GFileInfo<!---->s, whereas the
* synchronous will only return the next file in the enumerator.
*
* 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().
*
**/
G_DEFINE_TYPE (GFileEnumerator, g_file_enumerator, G_TYPE_OBJECT);
struct _GFileEnumeratorPrivate {
/* TODO: Should be public for subclasses? */
GFile *container;
guint closed : 1;
guint pending : 1;
GAsyncReadyCallback outstanding_callback;
GError *outstanding_error;
};
enum {
PROP_0,
PROP_CONTAINER
};
static void g_file_enumerator_real_next_files_async (GFileEnumerator *enumerator,
int num_files,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
static GList * g_file_enumerator_real_next_files_finish (GFileEnumerator *enumerator,
GAsyncResult *res,
GError **error);
static void g_file_enumerator_real_close_async (GFileEnumerator *enumerator,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data);
static gboolean g_file_enumerator_real_close_finish (GFileEnumerator *enumerator,
GAsyncResult *res,
GError **error);
static void
g_file_enumerator_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec)
{
GFileEnumerator *enumerator;
enumerator = G_FILE_ENUMERATOR (object);
switch (property_id) {
case PROP_CONTAINER:
enumerator->priv->container = g_value_dup_object (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static void
g_file_enumerator_dispose (GObject *object)
{
GFileEnumerator *enumerator;
enumerator = G_FILE_ENUMERATOR (object);
if (enumerator->priv->container) {
g_object_unref (enumerator->priv->container);
enumerator->priv->container = NULL;
}
G_OBJECT_CLASS (g_file_enumerator_parent_class)->dispose (object);
}
static void
g_file_enumerator_finalize (GObject *object)
{
GFileEnumerator *enumerator;
enumerator = G_FILE_ENUMERATOR (object);
if (!enumerator->priv->closed)
g_file_enumerator_close (enumerator, NULL, NULL);
G_OBJECT_CLASS (g_file_enumerator_parent_class)->finalize (object);
}
static void
g_file_enumerator_class_init (GFileEnumeratorClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
g_type_class_add_private (klass, sizeof (GFileEnumeratorPrivate));
gobject_class->set_property = g_file_enumerator_set_property;
gobject_class->dispose = g_file_enumerator_dispose;
gobject_class->finalize = g_file_enumerator_finalize;
klass->next_files_async = g_file_enumerator_real_next_files_async;
klass->next_files_finish = g_file_enumerator_real_next_files_finish;
klass->close_async = g_file_enumerator_real_close_async;
klass->close_finish = g_file_enumerator_real_close_finish;
g_object_class_install_property
(gobject_class, PROP_CONTAINER,
g_param_spec_object ("container", P_("Container"),
P_("The container that is being enumerated"),
G_TYPE_FILE,
G_PARAM_WRITABLE |
G_PARAM_CONSTRUCT_ONLY |
G_PARAM_STATIC_STRINGS));
}
static void
g_file_enumerator_init (GFileEnumerator *enumerator)
{
enumerator->priv = G_TYPE_INSTANCE_GET_PRIVATE (enumerator,
G_TYPE_FILE_ENUMERATOR,
GFileEnumeratorPrivate);
}
/**
* g_file_enumerator_next_file:
* @enumerator: a #GFileEnumerator.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* 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.
*
* 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.
*
* Return value: (transfer full): A #GFileInfo or %NULL on error or end of enumerator.
* Free the returned object with g_object_unref() when no longer needed.
**/
GFileInfo *
g_file_enumerator_next_file (GFileEnumerator *enumerator,
GCancellable *cancellable,
GError **error)
{
GFileEnumeratorClass *class;
GFileInfo *info;
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), NULL);
g_return_val_if_fail (enumerator != NULL, NULL);
if (enumerator->priv->closed)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
_("Enumerator is closed"));
return NULL;
}
if (enumerator->priv->pending)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
_("File enumerator has outstanding operation"));
return NULL;
}
if (enumerator->priv->outstanding_error)
{
g_propagate_error (error, enumerator->priv->outstanding_error);
enumerator->priv->outstanding_error = NULL;
return NULL;
}
class = G_FILE_ENUMERATOR_GET_CLASS (enumerator);
if (cancellable)
g_cancellable_push_current (cancellable);
enumerator->priv->pending = TRUE;
info = (* class->next_file) (enumerator, cancellable, error);
enumerator->priv->pending = FALSE;
if (cancellable)
g_cancellable_pop_current (cancellable);
return info;
}
/**
* g_file_enumerator_close:
* @enumerator: a #GFileEnumerator.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: location to store the error occurring, or %NULL to ignore
*
* 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.
*
* Return value: #TRUE on success or #FALSE on error.
**/
gboolean
g_file_enumerator_close (GFileEnumerator *enumerator,
GCancellable *cancellable,
GError **error)
{
GFileEnumeratorClass *class;
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), FALSE);
g_return_val_if_fail (enumerator != NULL, FALSE);
class = G_FILE_ENUMERATOR_GET_CLASS (enumerator);
if (enumerator->priv->closed)
return TRUE;
if (enumerator->priv->pending)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PENDING,
_("File enumerator has outstanding operation"));
return FALSE;
}
if (cancellable)
g_cancellable_push_current (cancellable);
enumerator->priv->pending = TRUE;
(* class->close_fn) (enumerator, cancellable, error);
enumerator->priv->pending = FALSE;
enumerator->priv->closed = TRUE;
if (cancellable)
g_cancellable_pop_current (cancellable);
return TRUE;
}
static void
next_async_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GFileEnumerator *enumerator = G_FILE_ENUMERATOR (source_object);
enumerator->priv->pending = FALSE;
if (enumerator->priv->outstanding_callback)
(*enumerator->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (enumerator);
}
/**
* g_file_enumerator_next_files_async:
* @enumerator: a #GFileEnumerator.
* @num_files: the number of file info objects to request
* @io_priority: the <link linkend="gioscheduler">io priority</link>
* of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): a #GAsyncReadyCallback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* 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.
*
* 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.
**/
void
g_file_enumerator_next_files_async (GFileEnumerator *enumerator,
int num_files,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GFileEnumeratorClass *class;
GSimpleAsyncResult *simple;
g_return_if_fail (G_IS_FILE_ENUMERATOR (enumerator));
g_return_if_fail (enumerator != NULL);
g_return_if_fail (num_files >= 0);
if (num_files == 0)
{
simple = g_simple_async_result_new (G_OBJECT (enumerator),
callback,
user_data,
g_file_enumerator_next_files_async);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
return;
}
if (enumerator->priv->closed)
{
g_simple_async_report_error_in_idle (G_OBJECT (enumerator),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_CLOSED,
_("File enumerator is already closed"));
return;
}
if (enumerator->priv->pending)
{
g_simple_async_report_error_in_idle (G_OBJECT (enumerator),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_PENDING,
_("File enumerator has outstanding operation"));
return;
}
class = G_FILE_ENUMERATOR_GET_CLASS (enumerator);
enumerator->priv->pending = TRUE;
enumerator->priv->outstanding_callback = callback;
g_object_ref (enumerator);
(* class->next_files_async) (enumerator, num_files, io_priority, cancellable,
next_async_callback_wrapper, user_data);
}
/**
* g_file_enumerator_next_files_finish:
* @enumerator: a #GFileEnumerator.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes the asynchronous operation started with g_file_enumerator_next_files_async().
*
* Returns: (transfer full) (element-type Gio.FileInfo): a #GList of #GFileInfo<!---->s. You must free the list with
* g_list_free() and unref the infos with g_object_unref() when you're
* done with them.
**/
GList *
g_file_enumerator_next_files_finish (GFileEnumerator *enumerator,
GAsyncResult *result,
GError **error)
{
GFileEnumeratorClass *class;
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), NULL);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
if (g_async_result_legacy_propagate_error (result, error))
return NULL;
else if (g_async_result_is_tagged (result, g_file_enumerator_next_files_async))
{
/* Special case read of 0 files */
return NULL;
}
class = G_FILE_ENUMERATOR_GET_CLASS (enumerator);
return class->next_files_finish (enumerator, result, error);
}
static void
close_async_callback_wrapper (GObject *source_object,
GAsyncResult *res,
gpointer user_data)
{
GFileEnumerator *enumerator = G_FILE_ENUMERATOR (source_object);
enumerator->priv->pending = FALSE;
enumerator->priv->closed = TRUE;
if (enumerator->priv->outstanding_callback)
(*enumerator->priv->outstanding_callback) (source_object, res, user_data);
g_object_unref (enumerator);
}
/**
* g_file_enumerator_close_async:
* @enumerator: a #GFileEnumerator.
* @io_priority: the <link linkend="io-priority">I/O priority</link>
* of the request.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @callback: (scope async): a #GAsyncReadyCallback to call when the request is satisfied
* @user_data: (closure): the data to pass to callback function
*
* 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().
**/
void
g_file_enumerator_close_async (GFileEnumerator *enumerator,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GFileEnumeratorClass *class;
g_return_if_fail (G_IS_FILE_ENUMERATOR (enumerator));
if (enumerator->priv->closed)
{
g_simple_async_report_error_in_idle (G_OBJECT (enumerator),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_CLOSED,
_("File enumerator is already closed"));
return;
}
if (enumerator->priv->pending)
{
g_simple_async_report_error_in_idle (G_OBJECT (enumerator),
callback,
user_data,
G_IO_ERROR, G_IO_ERROR_PENDING,
_("File enumerator has outstanding operation"));
return;
}
class = G_FILE_ENUMERATOR_GET_CLASS (enumerator);
enumerator->priv->pending = TRUE;
enumerator->priv->outstanding_callback = callback;
g_object_ref (enumerator);
(* class->close_async) (enumerator, io_priority, cancellable,
close_async_callback_wrapper, user_data);
}
/**
* g_file_enumerator_close_finish:
* @enumerator: a #GFileEnumerator.
* @result: a #GAsyncResult.
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* 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.
*
* Returns: %TRUE if the close operation has finished successfully.
**/
gboolean
g_file_enumerator_close_finish (GFileEnumerator *enumerator,
GAsyncResult *result,
GError **error)
{
GFileEnumeratorClass *class;
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), FALSE);
g_return_val_if_fail (G_IS_ASYNC_RESULT (result), FALSE);
if (g_async_result_legacy_propagate_error (result, error))
return FALSE;
class = G_FILE_ENUMERATOR_GET_CLASS (enumerator);
return class->close_finish (enumerator, result, error);
}
/**
* g_file_enumerator_is_closed:
* @enumerator: a #GFileEnumerator.
*
* Checks if the file enumerator has been closed.
*
* Returns: %TRUE if the @enumerator is closed.
**/
gboolean
g_file_enumerator_is_closed (GFileEnumerator *enumerator)
{
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), TRUE);
return enumerator->priv->closed;
}
/**
* g_file_enumerator_has_pending:
* @enumerator: a #GFileEnumerator.
*
* Checks if the file enumerator has pending operations.
*
* Returns: %TRUE if the @enumerator has pending operations.
**/
gboolean
g_file_enumerator_has_pending (GFileEnumerator *enumerator)
{
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), TRUE);
return enumerator->priv->pending;
}
/**
* g_file_enumerator_set_pending:
* @enumerator: a #GFileEnumerator.
* @pending: a boolean value.
*
* Sets the file enumerator as having pending operations.
**/
void
g_file_enumerator_set_pending (GFileEnumerator *enumerator,
gboolean pending)
{
g_return_if_fail (G_IS_FILE_ENUMERATOR (enumerator));
enumerator->priv->pending = pending;
}
/**
* g_file_enumerator_get_container:
* @enumerator: a #GFileEnumerator
*
* Get the #GFile container which is being enumerated.
*
* Returns: (transfer none): the #GFile which is being enumerated.
*
* Since: 2.18
*/
GFile *
g_file_enumerator_get_container (GFileEnumerator *enumerator)
{
g_return_val_if_fail (G_IS_FILE_ENUMERATOR (enumerator), NULL);
return enumerator->priv->container;
}
typedef struct {
int num_files;
GList *files;
} NextAsyncOp;
static void
next_async_op_free (NextAsyncOp *op)
{
/* Free the list, if finish wasn't called */
g_list_free_full (op->files, g_object_unref);
g_free (op);
}
static void
next_files_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
NextAsyncOp *op;
GFileEnumeratorClass *class;
GError *error = NULL;
GFileInfo *info;
GFileEnumerator *enumerator;
int i;
enumerator = G_FILE_ENUMERATOR (object);
op = g_simple_async_result_get_op_res_gpointer (res);
class = G_FILE_ENUMERATOR_GET_CLASS (object);
for (i = 0; i < op->num_files; i++)
{
if (g_cancellable_set_error_if_cancelled (cancellable, &error))
info = NULL;
else
info = class->next_file (enumerator, cancellable, &error);
if (info == NULL)
{
/* If we get an error after first file, return that on next operation */
if (error != NULL && i > 0)
{
if (error->domain == G_IO_ERROR &&
error->code == G_IO_ERROR_CANCELLED)
g_error_free (error); /* Never propagate cancel errors to other call */
else
enumerator->priv->outstanding_error = error;
error = NULL;
}
break;
}
else
op->files = g_list_prepend (op->files, info);
}
}
static void
g_file_enumerator_real_next_files_async (GFileEnumerator *enumerator,
int num_files,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
NextAsyncOp *op;
op = g_new0 (NextAsyncOp, 1);
op->num_files = num_files;
op->files = NULL;
res = g_simple_async_result_new (G_OBJECT (enumerator), callback, user_data, g_file_enumerator_real_next_files_async);
g_simple_async_result_set_op_res_gpointer (res, op, (GDestroyNotify) next_async_op_free);
g_simple_async_result_run_in_thread (res, next_files_thread, io_priority, cancellable);
g_object_unref (res);
}
static GList *
g_file_enumerator_real_next_files_finish (GFileEnumerator *enumerator,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
NextAsyncOp *op;
GList *res;
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
g_file_enumerator_real_next_files_async);
if (g_simple_async_result_propagate_error (simple, error))
return NULL;
op = g_simple_async_result_get_op_res_gpointer (simple);
res = op->files;
op->files = NULL;
return res;
}
static void
close_async_thread (GSimpleAsyncResult *res,
GObject *object,
GCancellable *cancellable)
{
GFileEnumeratorClass *class;
GError *error = NULL;
gboolean result;
/* Auto handling of cancelation disabled, and ignore
cancellation, since we want to close things anyway, although
possibly in a quick-n-dirty way. At least we never want to leak
open handles */
class = G_FILE_ENUMERATOR_GET_CLASS (object);
result = class->close_fn (G_FILE_ENUMERATOR (object), cancellable, &error);
if (!result)
g_simple_async_result_take_error (res, error);
}
static void
g_file_enumerator_real_close_async (GFileEnumerator *enumerator,
int io_priority,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GSimpleAsyncResult *res;
res = g_simple_async_result_new (G_OBJECT (enumerator),
callback,
user_data,
g_file_enumerator_real_close_async);
g_simple_async_result_set_handle_cancellation (res, FALSE);
g_simple_async_result_run_in_thread (res,
close_async_thread,
io_priority,
cancellable);
g_object_unref (res);
}
static gboolean
g_file_enumerator_real_close_finish (GFileEnumerator *enumerator,
GAsyncResult *result,
GError **error)
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
g_warn_if_fail (g_simple_async_result_get_source_tag (simple) ==
g_file_enumerator_real_close_async);
if (g_simple_async_result_propagate_error (simple, error))
return FALSE;
return TRUE;
}
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