/*
 * libvirt-gobject-input-stream.h: libvirt gobject integration
 *
 * Copyright (C) 2011 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 2.1 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, see
 * <http://www.gnu.org/licenses/>.
 *
 * Authors: Daniel P. Berrange <berrange@redhat.com>
 *          Marc-André Lureau <marcandre.lureau@redhat.com>
 */

#include <config.h>

#include <libvirt/virterror.h>
#include <string.h>

#include "libvirt-glib/libvirt-glib.h"
#include "libvirt-gobject/libvirt-gobject.h"
#include "libvirt-gobject-input-stream.h"
#include "libvirt-gobject-compat.h"

enum
{
    PROP_0,
    PROP_STREAM
};

struct _GVirInputStreamPrivate
{
    GVirStream *stream;

    /* pending operation metadata */
    GTask *task;
    gpointer buffer;
    gsize count;
};

#define gvir_input_stream_get_type _gvir_input_stream_get_type
G_DEFINE_TYPE_WITH_PRIVATE(GVirInputStream, gvir_input_stream, G_TYPE_INPUT_STREAM);

static void gvir_input_stream_get_property(GObject *object,
                                           guint prop_id,
                                           GValue *value,
                                           GParamSpec *pspec)
{
    GVirInputStream *stream = GVIR_INPUT_STREAM(object);

    switch (prop_id) {
    case PROP_STREAM:
        g_value_set_object(value, stream->priv->stream);
        break;

    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
    }
}

static void gvir_input_stream_set_property(GObject *object,
                                           guint prop_id,
                                           const GValue *value,
                                           GParamSpec *pspec)
{
    GVirInputStream *stream = GVIR_INPUT_STREAM(object);

    switch (prop_id) {
    case PROP_STREAM:
        stream->priv->stream = g_value_get_object(value);
        break;

    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
    }
}

static void gvir_input_stream_finalize(GObject *object)
{
    GVirInputStream *stream = GVIR_INPUT_STREAM(object);

    stream->priv->stream = NULL; // unowned

    if (G_OBJECT_CLASS(gvir_input_stream_parent_class)->finalize)
        (*G_OBJECT_CLASS(gvir_input_stream_parent_class)->finalize)(object);
}

static gboolean
gvir_input_stream_read_ready(GVirStream *stream,
                             GVirStreamIOCondition cond,
                             void *opaque)
{
    GVirInputStream *input_stream = GVIR_INPUT_STREAM(opaque);
    GVirInputStreamPrivate *priv = input_stream->priv;
    GTask *task = priv->task;
    GCancellable *cancellable = g_task_get_cancellable(task);
    GError *error = NULL;
    gssize result;

    priv->task = NULL;

    if (!(cond & GVIR_STREAM_IO_CONDITION_READABLE)) {
        g_warn_if_reached();
        g_task_return_new_error(task,
                                G_IO_ERROR,
                                G_IO_ERROR_INVALID_ARGUMENT,
                                "%s",
                                "Expected stream to be readable");
        goto cleanup;
    }

    result = gvir_stream_receive(stream, priv->buffer, priv->count,
                                 cancellable, &error);
    if (error != NULL) {
        if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK)) {
            g_warn_if_reached();
            g_task_return_new_error(task,
                                    G_IO_ERROR,
                                    G_IO_ERROR_INVALID_ARGUMENT,
                                    "%s",
                                    "Expected stream to be readable");
            g_error_free (error);
        } else {
            g_task_return_error(task, error);
        }

        goto cleanup;
    }

    g_task_return_int(task, result);

cleanup:
    g_object_unref(task);
    return FALSE;
}

static void gvir_input_stream_read_async(GInputStream *stream,
                                         void *buffer,
                                         gsize count,
                                         int io_priority G_GNUC_UNUSED,
                                         GCancellable *cancellable,
                                         GAsyncReadyCallback callback,
                                         gpointer user_data)
{
    GVirInputStream *input_stream = GVIR_INPUT_STREAM(stream);

    g_return_if_fail(GVIR_IS_INPUT_STREAM(stream));
    g_return_if_fail(input_stream->priv->task == NULL);

    gvir_stream_add_watch_full(input_stream->priv->stream,
                               G_PRIORITY_DEFAULT,
                               GVIR_STREAM_IO_CONDITION_READABLE,
                               gvir_input_stream_read_ready,
                               g_object_ref(stream),
                               (GDestroyNotify)g_object_unref);

    input_stream->priv->task =
        g_task_new(stream, cancellable, callback, user_data);
    input_stream->priv->buffer = buffer;
    input_stream->priv->count = count;
}


static gssize gvir_input_stream_read_finish(GInputStream *stream,
                                            GAsyncResult *result,
                                            GError **error)
{
    GVirInputStream *input_stream = GVIR_INPUT_STREAM(stream);
    virStreamPtr handle;
    gssize count;

    g_return_val_if_fail(GVIR_IS_INPUT_STREAM(stream), -1);
    g_return_val_if_fail(g_task_is_valid(result, stream), -1);
    g_return_val_if_fail(error == NULL || *error == NULL, -1);
    g_object_get(input_stream->priv->stream, "handle", &handle, NULL);

    count = g_task_propagate_int(G_TASK(result), error);

    virStreamFree(handle);

    return count;
}


static void gvir_input_stream_class_init(GVirInputStreamClass *klass)
{
    GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
    GInputStreamClass *ginputstream_class = G_INPUT_STREAM_CLASS(klass);

    gobject_class->finalize = gvir_input_stream_finalize;
    gobject_class->get_property = gvir_input_stream_get_property;
    gobject_class->set_property = gvir_input_stream_set_property;

    ginputstream_class->read_fn = NULL;
    ginputstream_class->read_async = gvir_input_stream_read_async;
    ginputstream_class->read_finish = gvir_input_stream_read_finish;

    g_object_class_install_property(gobject_class, PROP_STREAM,
                                    g_param_spec_object("stream",
                                                        "stream",
                                                        "GVirStream",
                                                        GVIR_TYPE_STREAM, G_PARAM_CONSTRUCT_ONLY |
                                                        G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
}

static void gvir_input_stream_init(GVirInputStream *stream)
{
    stream->priv = G_TYPE_INSTANCE_GET_PRIVATE(stream, GVIR_TYPE_INPUT_STREAM, GVirInputStreamPrivate);
}

GVirInputStream *_gvir_input_stream_new(GVirStream *stream)
{
    return GVIR_INPUT_STREAM(g_object_new(GVIR_TYPE_INPUT_STREAM, "stream", stream, NULL));
}