path: root/src/ephy-python-extension.c

/*
 *  Copyright © 2003 Marco Pesenti Gritti
 *  Copyright © 2003 Christian Persch
 *  Copyright © 2004, 2005 Adam Hooper
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 *  $Id$
 */

#include "Python.h"

#include "config.h"

#include "ephy-python-extension.h"
#include "ephy-python.h"

#define NO_IMPORT_PYGOBJECT
#include <pygobject.h>

#include "ephy-extension.h"
#include "ephy-window.h"
#include "ephy-tab.h"
#include "ephy-file-helpers.h"
#include "ephy-debug.h"

#define EPHY_PYTHON_EXTENSION_GET_PRIVATE(object) (G_TYPE_INSTANCE_GET_PRIVATE ((object), EPHY_TYPE_PYTHON_EXTENSION, EphyPythonExtensionPrivate))

struct _EphyPythonExtensionPrivate
{
    char *filename;
    PyObject *module;
};

enum
{
    PROP_0,
    PROP_FILENAME
};

static GObjectClass *parent_class = NULL;

static int
set_python_search_path (const char *filename)
{
    char *dirname;
    char *dot_dir;
    int ret = 2;
    PyObject *sys_path;
    PyObject *pValue;

    sys_path = PySys_GetObject ("path");

    /* Systems extensions dir */
    pValue = PyString_FromString (EXTENSIONS_DIR);
    PyList_Insert (sys_path, 0, pValue);
    Py_DECREF (pValue);

    /* Home dir */
    dot_dir = g_strconcat (ephy_dot_dir (), "/extensions", NULL);
    pValue = PyString_FromString (dot_dir);
    PyList_Insert (sys_path, 0, pValue);
    Py_DECREF (pValue);
    g_free (dot_dir);

    /* Absolute path specified in .xml file */
    dirname = g_path_get_dirname (filename);
    if (g_path_is_absolute (dirname))
    {
        pValue = PyString_FromString (dirname);
        PyList_Insert (sys_path, 0, pValue);
        Py_DECREF (pValue);
        ret++;
    }
    g_free (dirname);

    return ret;
}

static void
unset_python_search_path (int num_dirs)
{
    PyObject *sys_path = PySys_GetObject ("path");

    PySequence_DelSlice (sys_path, 0, num_dirs);
}

static void
ephy_python_extension_init (EphyPythonExtension *extension)
{
    LOG ("EphyPythonExtension initialising");

    extension->priv = EPHY_PYTHON_EXTENSION_GET_PRIVATE (extension);
}

static GObject *
ephy_python_extension_constructor (GType type,
                   guint n_construct_properties,
                   GObjectConstructParam *construct_params)
{
    GObject *object;
    EphyPythonExtension *ext;
    char *module_name;  /* filename minus optional ".py" */
                /* Note: could equally be a directory */
    PyObject *pModules, *pModule, *pReload;
              
    int num_temp_paths;

    object = parent_class->constructor (type, n_construct_properties,
                        construct_params);

    ext = EPHY_PYTHON_EXTENSION (object);

    module_name = g_path_get_basename (ext->priv->filename);

    num_temp_paths = set_python_search_path (ext->priv->filename);

    pModules = PySys_GetObject ("modules");
    g_assert (pModules != NULL);

    pModule = PyDict_GetItemString (pModules, module_name);

    if (pModule == NULL)
    {
        pModule = PyImport_ImportModule (module_name);

        if (pModule == NULL)
        {
            PyErr_Print ();
            PyErr_Clear ();
            g_warning ("Could not initialize Python module '%s'",
                   module_name);
        }
    }
    else
    {
        pReload = PyImport_ReloadModule (pModule);

        if (pReload == NULL)
        {
            PyErr_Print ();
            PyErr_Clear ();
            g_warning ("Could not reload Python module '%s'\n"
                   "Falling back to previous version",
                   module_name);
        }
        else
        {
            Py_DECREF (pReload);
        }
    }

    unset_python_search_path (num_temp_paths);

    ext->priv->module = pModule;

    g_free (module_name);

    return object;
}

static void
ephy_python_extension_finalize (GObject *object)
{
    EphyPythonExtension *extension =
            EPHY_PYTHON_EXTENSION (object);

    LOG ("EphyPythonExtension finalizing");

    g_free (extension->priv->filename);
    Py_XDECREF (extension->priv->module);

    G_OBJECT_CLASS (parent_class)->finalize (object);
}

static void
call_python_func (EphyExtension *extension,
          const char *func_name,
          EphyWindow *window,
          EphyTab *tab) /* HACK: tab may be NULL */
{
    PyObject *pDict, *pFunc;
    PyObject *pArgs, *pValue, *pTab = NULL, *pWindow;
    EphyPythonExtension *py_ext;
    
    py_ext = EPHY_PYTHON_EXTENSION (extension);

        /* Happens if the module load fails, e.g. python couldn't
         * parse it, so be quiet about it, we will have already warned */
        if (py_ext->priv->module == NULL)
    {
        return;
    }

    pDict = PyModule_GetDict (py_ext->priv->module);
    pFunc = PyDict_GetItemString (pDict, func_name);

    if (pFunc && PyCallable_Check (pFunc))
    {
        pArgs = PyTuple_New (tab == NULL ? 1 : 2);

        pWindow = pygobject_new (G_OBJECT (window));
        PyTuple_SetItem (pArgs, 0, pWindow);

        if (tab != NULL)
        {
            pTab = pygobject_new (G_OBJECT (tab));
            PyTuple_SetItem (pArgs, 1, pTab);
        }

        pValue = PyObject_CallObject (pFunc, pArgs);
        if (pValue == NULL)
        {
            PyErr_Print ();
            PyErr_Clear ();
            g_warning ("Python code for '%s' failed to execute",
                   func_name);
        }
        Py_XDECREF (pValue);
        Py_DECREF (pArgs);
    }
    else
    {
        if (PyErr_Occurred ())
        {
            PyErr_Print ();
            PyErr_Clear ();
        }
    }
}

static void
impl_attach_tab (EphyExtension *extension,
         EphyWindow *window,
         EphyTab *tab)
{
    call_python_func (extension, "attach_tab", window, tab);
}

static void
impl_detach_tab (EphyExtension *extension,
         EphyWindow *window,
         EphyTab *tab)
{
    call_python_func (extension, "detach_tab", window, tab);

    ephy_python_schedule_gc ();
}

static void
impl_attach_window (EphyExtension *extension,
            EphyWindow *window)
{
    call_python_func (extension, "attach_window", window, NULL);
}

static void
impl_detach_window (EphyExtension *extension,
            EphyWindow *window)
{
    call_python_func (extension, "detach_window", window, NULL);

    ephy_python_schedule_gc ();
}

static void
ephy_python_extension_iface_init (EphyExtensionIface *iface)
{
    iface->attach_tab = impl_attach_tab;
    iface->detach_tab = impl_detach_tab;
    iface->attach_window = impl_attach_window;
    iface->detach_window = impl_detach_window;
}

static void
ephy_python_extension_get_property (GObject *object,
                    guint prop_id,
                    GValue *value,
                    GParamSpec *pspec)
{
    /* no readable properties */
    g_return_if_reached ();
}

static void
ephy_python_extension_set_property (GObject *object,
                    guint prop_id,
                    const GValue *value,
                    GParamSpec *pspec)
{
    EphyPythonExtension *ext = EPHY_PYTHON_EXTENSION (object);

    switch (prop_id)
    {
        case PROP_FILENAME:
            ext->priv->filename = g_value_dup_string (value);
            break;
        default:
            g_return_if_reached ();
    }
}

static void
ephy_python_extension_class_init (EphyPythonExtensionClass *klass)
{
    GObjectClass *object_class = G_OBJECT_CLASS (klass);

    parent_class = g_type_class_peek_parent (klass);

    object_class->finalize = ephy_python_extension_finalize;
    object_class->constructor = ephy_python_extension_constructor;
    object_class->get_property = ephy_python_extension_get_property;
    object_class->set_property = ephy_python_extension_set_property;

    g_object_class_install_property
            (object_class,
             PROP_FILENAME,
             g_param_spec_string ("filename",
                          "Filename",
                          "Filename",
                          NULL,
                          G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB | G_PARAM_CONSTRUCT_ONLY));

    g_type_class_add_private (object_class, sizeof (EphyPythonExtensionPrivate));
}

GType
ephy_python_extension_get_type (void)
{
    static GType type = 0;

    if (G_UNLIKELY (type == 0))
    {
        const GTypeInfo our_info =
        {
            sizeof (EphyPythonExtensionClass),
            NULL, /* base_init */
            NULL, /* base_finalize */
            (GClassInitFunc) ephy_python_extension_class_init,
            NULL,
            NULL, /* class_data */
            sizeof (EphyPythonExtension),
            0, /* n_preallocs */
            (GInstanceInitFunc) ephy_python_extension_init
        };
        const GInterfaceInfo extension_info =
        {
            (GInterfaceInitFunc) ephy_python_extension_iface_init,
            NULL,
            NULL
        };

        type = g_type_register_static (G_TYPE_OBJECT, "EphyPythonExtension",
                           &our_info, 0);

        g_type_add_interface_static (type, EPHY_TYPE_EXTENSION, &extension_info);
    }

    return type;
}