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

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* ETextModel - Text item model for evolution.
 * Copyright (C) 2000 Helix Code, Inc.
 *
 * Author: Chris Lahey <clahey@umich.edu>
 *
 * A majority of code taken from:
 *
 * Text item type for GnomeCanvas widget
 *
 * GnomeCanvas is basically a port of the Tk toolkit's most excellent
 * canvas widget.  Tk is copyrighted by the Regents of the University
 * of California, Sun Microsystems, and other parties.
 *
 * Copyright (C) 1998 The Free Software Foundation
 *
 * Author: Federico Mena <federico@nuclecu.unam.mx> */

#undef  PARANOID_DEBUGGING

#include <config.h>
#include <ctype.h>
#include <string.h>
#include <gtk/gtksignal.h>
#include "e-text-model-repos.h"
#include "e-text-model.h"

#define CLASS(obj) (E_TEXT_MODEL_CLASS (GTK_OBJECT (obj)->klass))

enum {
    E_TEXT_MODEL_CHANGED,
    E_TEXT_MODEL_REPOSITION,
    E_TEXT_MODEL_OBJECT_ACTIVATED,
    E_TEXT_MODEL_LAST_SIGNAL
};

static guint e_text_model_signals[E_TEXT_MODEL_LAST_SIGNAL] = { 0 };

struct _ETextModelPrivate {
    gchar   *text;
    gint     len;
};

static void e_text_model_class_init (ETextModelClass *class);
static void e_text_model_init       (ETextModel *model);
static void e_text_model_destroy    (GtkObject *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);

static GtkObject *parent_class;



/**
 * e_text_model_get_type:
 * @void: 
 * 
 * Registers the &ETextModel class if necessary, and returns the type ID
 * associated to it.
 * 
 * Return value: The type ID of the &ETextModel class.
 **/
GtkType
e_text_model_get_type (void)
{
    static GtkType model_type = 0;

    if (!model_type) {
        GtkTypeInfo model_info = {
            "ETextModel",
            sizeof (ETextModel),
            sizeof (ETextModelClass),
            (GtkClassInitFunc) e_text_model_class_init,
            (GtkObjectInitFunc) e_text_model_init,
            NULL, /* reserved_1 */
            NULL, /* reserved_2 */
            (GtkClassInitFunc) NULL
        };

        model_type = gtk_type_unique (gtk_object_get_type (), &model_info);
    }

    return model_type;
}

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

    object_class = (GtkObjectClass *) klass;

    parent_class = gtk_type_class (gtk_object_get_type ());

    e_text_model_signals[E_TEXT_MODEL_CHANGED] =
        gtk_signal_new ("changed",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ETextModelClass, changed),
                gtk_marshal_NONE__NONE,
                GTK_TYPE_NONE, 0);

    e_text_model_signals[E_TEXT_MODEL_REPOSITION] =
        gtk_signal_new ("reposition",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ETextModelClass, reposition),
                gtk_marshal_NONE__POINTER_POINTER,
                GTK_TYPE_NONE, 2,
                GTK_TYPE_POINTER, GTK_TYPE_POINTER);

    e_text_model_signals[E_TEXT_MODEL_OBJECT_ACTIVATED] =
        gtk_signal_new ("object_activated",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (ETextModelClass, object_activated),
                gtk_marshal_NONE__INT,
                GTK_TYPE_NONE, 1,
                GTK_TYPE_INT);
    
    gtk_object_class_add_signals (object_class, e_text_model_signals, E_TEXT_MODEL_LAST_SIGNAL);
    
    /* 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->destroy = e_text_model_destroy;
}

/* 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_strdup ("");
    model->priv->len  = 0;
}

/* Destroy handler for the text item */
static void
e_text_model_destroy (GtkObject *object)
{
    ETextModel *model;

    g_return_if_fail (object != NULL);
    g_return_if_fail (E_IS_TEXT_MODEL (object));

    model = E_TEXT_MODEL (object);

    g_free (model->priv->text);

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

    if (GTK_OBJECT_CLASS (parent_class)->destroy)
        GTK_OBJECT_CLASS (parent_class)->destroy (object);
}

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

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

    return pos;
}

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

static gint
e_text_model_real_get_text_length (ETextModel *model)
{
    if (model->priv->len < 0)
        model->priv->len = strlen (e_text_model_get_text (model));

    return model->priv->len;
}

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 != NULL);

        g_free (model->priv->text);
        model->priv->text = NULL;
        model->priv->len = -1;

    } else if (model->priv->text == NULL || strcmp (model->priv->text, text)) {
        
        g_free (model->priv->text);
        model->priv->text = g_strdup (text);
        model->priv->len = -1;

        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)
{
    EReposInsertShift repos;
    gchar *new_text;
    gint ins_len;

    new_text = g_strdup_printf ("%.*s%s%s", position, model->priv->text, text, model->priv->text + position);
    ins_len = strlen (text);

    if (model->priv->text)
        g_free (model->priv->text);

    model->priv->text = new_text;
    
    if (model->priv->len >= 0)
        model->priv->len += ins_len;
    
    e_text_model_changed (model);

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

    e_text_model_reposition (model, e_repos_insert_shift, &repos);
}

static void
e_text_model_real_insert_length (ETextModel *model, gint position, const gchar *text, gint length)
{
    EReposInsertShift repos;
    gchar *new_text = g_strdup_printf ("%.*s%.*s%s", position, model->priv->text, length, text, model->priv->text + position);

    if (model->priv->text)
        g_free (model->priv->text);
    model->priv->text = new_text;

    if (model->priv->len >= 0)
        model->priv->len += 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;
 
    memmove (model->priv->text + position, model->priv->text + position + length, strlen (model->priv->text + position + length) + 1);
    
    if (model->priv->len >= 0)
        model->priv->len -= 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 (model != NULL);
    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 (CLASS (model)->objectify)
        CLASS (model)->objectify (model);

    gtk_signal_emit (GTK_OBJECT (model),
             e_text_model_signals[E_TEXT_MODEL_CHANGED]);
}

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

    gtk_signal_emit (GTK_OBJECT (model),
             e_text_model_signals[E_TEXT_MODEL_REPOSITION],
             fn, repos_data);
}

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

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

    return pos;
}

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

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

    return "";
}

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

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

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

#ifdef PARANOID_DEBUGGING
        const gchar *str = e_text_model_get_text (model);
        gint len2 = str ? strlen (str) : 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 ? strlen (str) : 0;
    }
}

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

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

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

    if (text == NULL)
        return;

    if (CLASS (model)->insert)
        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 (model != NULL);
    g_return_if_fail (E_IS_TEXT_MODEL (model));
    g_return_if_fail (length >= 0);


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

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

void
e_text_model_prepend (ETextModel *model, const gchar *text)
{
    g_return_if_fail (model != NULL);
    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 (model != NULL);
    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 (model != NULL);
    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 (CLASS (model)->delete)
        CLASS (model)->delete (model, position, length);
}

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

    if (CLASS (model)->obj_count)
        return 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 (model != NULL, NULL);
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), NULL);

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

    if (CLASS (model)->get_nth_obj)
        return 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 (model != NULL, NULL);
    g_return_val_if_fail (E_IS_TEXT_MODEL (model), NULL);

    obj = e_text_model_get_nth_object (model, n, &len);
    
    return obj ? g_strndup (obj, n) : 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 (model != NULL);
    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 = obj - txt;
    if (end)
        *end = obj - txt + len;
}

gint
e_text_model_get_object_at_offset (ETextModel *model, gint offset)
{
    g_return_val_if_fail (model != NULL, -1);
    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 (CLASS (model)->obj_at_offset) {

        return 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 (model != NULL, -1);
    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));

    gtk_signal_emit (GTK_OBJECT (model), e_text_model_signals[E_TEXT_MODEL_OBJECT_ACTIVATED], n);
}

ETextModel *
e_text_model_new (void)
{
    ETextModel *model = gtk_type_new (e_text_model_get_type ());
    return model;
}