path: root/widgets/text/e-text-model.c

/*
 * This program 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) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *      Chris Lahey <clahey@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#undef  PARANOID_DEBUGGING

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <ctype.h>
#include <string.h>

#include <gtk/gtk.h>

#include "e-util/e-util.h"

#include "e-text-model.h"
#include "e-text-model-repos.h"

enum {
    E_TEXT_MODEL_CHANGED,
    E_TEXT_MODEL_REPOSITION,
    E_TEXT_MODEL_OBJECT_ACTIVATED,
    E_TEXT_MODEL_CANCEL_COMPLETION,
    E_TEXT_MODEL_LAST_SIGNAL
};

static guint e_text_model_signals[E_TEXT_MODEL_LAST_SIGNAL] = { 0 };

struct _ETextModelPrivate {
    GString *text;
};

static void e_text_model_dispose        (GObject *object);

static gint e_text_model_real_validate_position
                        (ETextModel *, gint pos);
static const gchar *
        e_text_model_real_get_text  (ETextModel *model);
static gint e_text_model_real_get_text_length
                        (ETextModel *model);
static void e_text_model_real_set_text  (ETextModel *model,
                         const gchar *text);
static void e_text_model_real_insert    (ETextModel *model,
                         gint postion,
                         const gchar *text);
static void e_text_model_real_insert_length (ETextModel *model,
                         gint postion,
                         const gchar *text,
                         gint length);
static void e_text_model_real_delete    (ETextModel *model,
                         gint postion,
                         gint length);

G_DEFINE_TYPE (ETextModel, e_text_model, G_TYPE_OBJECT)

/* Class initialization function for the text item */
static void
e_text_model_class_init (ETextModelClass *klass)
{
    GObjectClass *object_class;

    object_class = (GObjectClass *) klass;

    e_text_model_signals[E_TEXT_MODEL_CHANGED] =
        g_signal_new ("changed",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ETextModelClass, changed),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__VOID,
                  G_TYPE_NONE, 0);

    e_text_model_signals[E_TEXT_MODEL_REPOSITION] =
        g_signal_new ("reposition",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ETextModelClass, reposition),
                  NULL, NULL,
                  e_marshal_NONE__POINTER_POINTER,
                  G_TYPE_NONE, 2,
                  G_TYPE_POINTER, G_TYPE_POINTER);

    e_text_model_signals[E_TEXT_MODEL_OBJECT_ACTIVATED] =
        g_signal_new ("object_activated",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ETextModelClass, object_activated),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__INT,
                  G_TYPE_NONE, 1,
                  G_TYPE_INT);

    e_text_model_signals[E_TEXT_MODEL_CANCEL_COMPLETION] =
        g_signal_new ("cancel_completion",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ETextModelClass, cancel_completion),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__VOID,
                  G_TYPE_NONE, 0);

    /* No default signal handlers. */
    klass->changed          = NULL;
    klass->reposition       = NULL;
    klass->object_activated = NULL;

    klass->validate_pos  = e_text_model_real_validate_position;

    klass->get_text      = e_text_model_real_get_text;
    klass->get_text_len  = e_text_model_real_get_text_length;
    klass->set_text      = e_text_model_real_set_text;
    klass->insert        = e_text_model_real_insert;
    klass->insert_length = e_text_model_real_insert_length;
    klass->delete        = e_text_model_real_delete;

    /* We explicitly don't define default handlers for these. */
    klass->objectify        = NULL;
    klass->obj_count        = NULL;
    klass->get_nth_obj      = NULL;

    object_class->dispose = e_text_model_dispose;
}

/* Object initialization function for the text item */
static void
e_text_model_init (ETextModel *model)
{
    model->priv = g_new0 (struct _ETextModelPrivate, 1);
    model->priv->text = g_string_new ("");
}

/* Dispose handler for the text item */
static void
e_text_model_dispose (GObject *object)
{
    ETextModel *model;

    g_return_if_fail (E_IS_TEXT_MODEL (object));

    model = E_TEXT_MODEL (object);

    if (model->priv) {
        g_string_free (model->priv->text, TRUE);

        g_free (model->priv);
        model->priv = NULL;
    }

    /* Chain up to parent's dispose() method. */
    G_OBJECT_CLASS (e_text_model_parent_class)->dispose (object);
}

static gint
e_text_model_real_validate_position (ETextModel *model,
                                     gint pos)
{
    gint len = e_text_model_get_text_length (model);

    if (pos < 0)
        pos = 0;
    else if (pos > len)
        pos = len;

    return pos;
}

static const gchar *
e_text_model_real_get_text (ETextModel *model)
{
    if (model->priv->text)
        return model->priv->text->str;
    else
        return "";
}

static gint
e_text_model_real_get_text_length (ETextModel *model)
{
    return g_utf8_strlen (model->priv->text->str, -1);
}

static void
e_text_model_real_set_text (ETextModel *model,
                            const gchar *text)
{
    EReposAbsolute repos;
    gboolean changed = FALSE;

    if (text == NULL) {
        changed = (*model->priv->text->str != '\0');

        g_string_set_size (model->priv->text, 0);

    } else if (*model->priv->text->str == '\0' ||
        strcmp (model->priv->text->str, text)) {

        g_string_assign (model->priv->text, text);

        changed = TRUE;
    }

    if (changed) {
        e_text_model_changed (model);
        repos.model = model;
        repos.pos = -1;
        e_text_model_reposition (model, e_repos_absolute, &repos);
    }
}

static void
e_text_model_real_insert (ETextModel *model,
                          gint position,
                          const gchar *text)
{
    e_text_model_insert_length (model, position, text, strlen (text));
}

static void
e_text_model_real_insert_length (ETextModel *model,
                                 gint position,
                                 const gchar *text,
                                 gint length)
{
    EReposInsertShift repos;
    gint model_len = e_text_model_real_get_text_length (model);
    gchar *offs;
    const gchar *p;
    gint byte_length, l;

    if (position > model_len)
        return;

    offs = g_utf8_offset_to_pointer (model->priv->text->str, position);

    for (p = text, l = 0;
         l < length;
         p = g_utf8_next_char (p), l++);

    byte_length = p - text;

    g_string_insert_len (model->priv->text,
                 offs - model->priv->text->str,
                 text, byte_length);

    e_text_model_changed (model);

    repos.model = model;
    repos.pos = position;
    repos.len = length;

    e_text_model_reposition (model, e_repos_insert_shift, &repos);
}

static void
e_text_model_real_delete (ETextModel *model,
                          gint position,
                          gint length)
{
    EReposDeleteShift repos;
    gint byte_position, byte_length;
    gchar *offs, *p;
    gint l;

    offs = g_utf8_offset_to_pointer (model->priv->text->str, position);
    byte_position = offs - model->priv->text->str;

    for (p = offs, l = 0;
         l < length;
         p = g_utf8_next_char (p), l++);

    byte_length = p - offs;

    g_string_erase (model->priv->text,
            byte_position, byte_length);

    e_text_model_changed (model);

    repos.model = model;
    repos.pos   = position;
    repos.len   = length;

    e_text_model_reposition (model, e_repos_delete_shift, &repos);
}

void
e_text_model_changed (ETextModel *model)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));

    /*
      Objectify before emitting any signal.
      While this method could, in theory, do pretty much anything, it is meant
      for scanning objects and converting substrings into embedded objects.
    */
    if (E_TEXT_MODEL_GET_CLASS (model)->objectify)
        E_TEXT_MODEL_GET_CLASS (model)->objectify (model);

    g_signal_emit (model,
               e_text_model_signals[E_TEXT_MODEL_CHANGED], 0);
}

void
e_text_model_cancel_completion (ETextModel *model)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));

    g_signal_emit (model, e_text_model_signals[E_TEXT_MODEL_CANCEL_COMPLETION], 0);
}

void
e_text_model_reposition (ETextModel *model,
                         ETextModelReposFn fn,
                         gpointer repos_data)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));
    g_return_if_fail (fn != NULL);

    g_signal_emit (model,
               e_text_model_signals[E_TEXT_MODEL_REPOSITION], 0,
               fn, repos_data);
}

gint
e_text_model_validate_position (ETextModel *model,
                                gint pos)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), 0);

    if (E_TEXT_MODEL_GET_CLASS (model)->validate_pos)
        pos = E_TEXT_MODEL_GET_CLASS (model)->validate_pos (model, pos);

    return pos;
}

const gchar *
e_text_model_get_text (ETextModel *model)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), NULL);

    if (E_TEXT_MODEL_GET_CLASS (model)->get_text)
        return E_TEXT_MODEL_GET_CLASS (model)->get_text (model);

    return "";
}

gint
e_text_model_get_text_length (ETextModel *model)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), 0);

    if (E_TEXT_MODEL_GET_CLASS (model)->get_text_len (model)) {

        gint len = E_TEXT_MODEL_GET_CLASS (model)->get_text_len (model);

#ifdef PARANOID_DEBUGGING
        const gchar *str = e_text_model_get_text (model);
        gint len2 = str ? g_utf8_strlen (str, -1) : 0;
        if (len != len)
            g_error ("\"%s\" length reported as %d, not %d.", str, len, len2);
#endif

        return len;

    } else {
        /* Calculate length the old-fashioned way... */
        const gchar *str = e_text_model_get_text (model);
        return str ? g_utf8_strlen (str, -1) : 0;
    }
}

void
e_text_model_set_text (ETextModel *model,
                       const gchar *text)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));

    if (E_TEXT_MODEL_GET_CLASS (model)->set_text)
        E_TEXT_MODEL_GET_CLASS (model)->set_text (model, text);
}

void
e_text_model_insert (ETextModel *model,
                     gint position,
                     const gchar *text)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));

    if (text == NULL)
        return;

    if (E_TEXT_MODEL_GET_CLASS (model)->insert)
        E_TEXT_MODEL_GET_CLASS (model)->insert (model, position, text);
}

void
e_text_model_insert_length (ETextModel *model,
                            gint position,
                            const gchar *text,
                            gint length)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));
    g_return_if_fail (length >= 0);

    if (text == NULL || length == 0)
        return;

    if (E_TEXT_MODEL_GET_CLASS (model)->insert_length)
        E_TEXT_MODEL_GET_CLASS (model)->insert_length (model, position, text, length);
}

void
e_text_model_prepend (ETextModel *model,
                      const gchar *text)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));

    if (text == NULL)
        return;

    e_text_model_insert (model, 0, text);
}

void
e_text_model_append (ETextModel *model,
                     const gchar *text)
{
    g_return_if_fail (E_IS_TEXT_MODEL (model));

    if (text == NULL)
        return;

    e_text_model_insert (model, e_text_model_get_text_length (model), text);
}

void
e_text_model_delete (ETextModel *model,
                     gint position,
                     gint length)
{
    gint txt_len;

    g_return_if_fail (E_IS_TEXT_MODEL (model));
    g_return_if_fail (length >= 0);

    txt_len = e_text_model_get_text_length (model);
    if (position + length > txt_len)
        length = txt_len - position;

    if (length <= 0)
        return;

    if (E_TEXT_MODEL_GET_CLASS (model)->delete)
        E_TEXT_MODEL_GET_CLASS (model)->delete (model, position, length);
}

gint
e_text_model_object_count (ETextModel *model)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), 0);

    if (E_TEXT_MODEL_GET_CLASS (model)->obj_count)
        return E_TEXT_MODEL_GET_CLASS (model)->obj_count (model);

    return 0;
}

const gchar *
e_text_model_get_nth_object (ETextModel *model,
                             gint n,
                             gint *len)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), NULL);

    if (n < 0 || n >= e_text_model_object_count (model))
        return NULL;

    if (E_TEXT_MODEL_GET_CLASS (model)->get_nth_obj)
        return E_TEXT_MODEL_GET_CLASS (model)->get_nth_obj (model, n, len);

    return NULL;
}

gchar *
e_text_model_strdup_nth_object (ETextModel *model,
                                gint n)
{
    const gchar *obj;
    gint len = 0;

    g_return_val_if_fail (E_IS_TEXT_MODEL (model), NULL);

    obj = e_text_model_get_nth_object (model, n, &len);

    if (obj) {
        gint byte_len;
        byte_len = g_utf8_offset_to_pointer (obj, len) - obj;
        return g_strndup (obj, byte_len);
    }
    else {
        return NULL;
    }
}

void
e_text_model_get_nth_object_bounds (ETextModel *model,
                                    gint n,
                                    gint *start,
                                    gint *end)
{
    const gchar *txt = NULL, *obj = NULL;
    gint len = 0;

    g_return_if_fail (E_IS_TEXT_MODEL (model));

    txt = e_text_model_get_text (model);
    obj = e_text_model_get_nth_object (model, n, &len);

    g_return_if_fail (obj != NULL);

    if (start)
        *start = g_utf8_pointer_to_offset (txt, obj);
    if (end)
        *end = *start + len;
}

gint
e_text_model_get_object_at_offset (ETextModel *model,
                                   gint offset)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), -1);

    if (offset < 0 || offset >= e_text_model_get_text_length (model))
        return -1;

    /* If an optimized version has been provided, we use it. */
    if (E_TEXT_MODEL_GET_CLASS (model)->obj_at_offset) {

        return E_TEXT_MODEL_GET_CLASS (model)->obj_at_offset (model, offset);

    } else {
        /* If not, we fake it.*/

        gint i, N, pos0, pos1;

        N = e_text_model_object_count (model);

        for (i = 0; i < N; ++i) {
            e_text_model_get_nth_object_bounds (model, i, &pos0, &pos1);
            if (pos0 <= offset && offset < pos1)
                return i;
        }

    }

    return -1;
}

gint
e_text_model_get_object_at_pointer (ETextModel *model,
                                    const gchar *s)
{
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), -1);
    g_return_val_if_fail (s != NULL, -1);

    return e_text_model_get_object_at_offset (
        model, s - e_text_model_get_text (model));
}

void
e_text_model_activate_nth_object (ETextModel *model,
                                  gint n)
{
    g_return_if_fail (model != NULL);
    g_return_if_fail (E_IS_TEXT_MODEL (model));
    g_return_if_fail (n >= 0);
    g_return_if_fail (n < e_text_model_object_count (model));

    g_signal_emit (model, e_text_model_signals[E_TEXT_MODEL_OBJECT_ACTIVATED], 0, n);
}

ETextModel *
e_text_model_new (void)
{
    ETextModel *model = g_object_new (E_TYPE_TEXT_MODEL, NULL);
    return model;
}