Reactivate the constructor of the filter and control dialogs

[lttv.git] / lttv / modules / gui / filter / filter.c

/* This file is part of the Linux Trace Toolkit viewer
 * Copyright (C) 2005 Simon Bouvier-Zappa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License Version 2 as
 * published by the Free Software Foundation;
 *
 * 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., 59 Temple Place - Suite 330, Boston, 
 * MA 02111-1307, USA.
 */

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

#include <glib.h>
#include <string.h>
#include <gtk/gtk.h>
#include <gdk/gdk.h>
#include <gdk/gdkkeysyms.h>

#include <lttv/lttv.h>
#include <lttv/module.h>
#include <lttv/hook.h>
#include <lttv/filter.h>

#include <lttvwindow/lttvwindow.h>
#include <lttvwindow/lttvwindowtraces.h>

#include "hGuiFilterInsert.xpm"


GSList *g_filter_list = NULL ;

/*! \file lttv/modules/gui/filter/filter.c
 *  \brief Graphic filter interface.
 *
 *  The gui filter facility gives the user an easy to use 
 *  basic interface to construct and modify at will a filter 
 *  expression.  User may either decide to write it himself in 
 *  expression text entry or add simple expressions using the 
 *  many choices boxes.
 *  
 *  \note The version of gtk-2.0 currently installed on 
 *  my desktop misses some function of the newer 
 *  gtk+ api.  For the time being, I'll use the older api 
 *  to keep compatibility with most systems.
 */

typedef struct _FilterViewerData FilterViewerData;
typedef struct _FilterViewerDataLine FilterViewerDataLine;

/*
 * Prototypes
 */
GtkWidget *guifilter_get_widget(FilterViewerData *fvd);
FilterViewerData *gui_filter(LttvPlugin *plugin);
void gui_filter_destructor(FilterViewerData *fvd);
FilterViewerDataLine* gui_filter_add_line(FilterViewerData *fvd);
void gui_filter_line_set_visible(FilterViewerDataLine *fvdl, gboolean v);
void gui_filter_line_reset(FilterViewerDataLine *fvdl);
GtkWidget* h_guifilter(LttvPlugin *plugin);
void filter_destroy_walk(gpointer data, gpointer user_data);
  
/*
 * Callback functions
 */
void callback_process_button(GtkWidget *widget, gpointer data);
gboolean callback_enter_check(GtkWidget *widget,
    GdkEventKey *event,
    gpointer user_data);
void callback_add_button(GtkWidget *widget, gpointer data);
void callback_logical_op_box(GtkWidget *widget, gpointer data);
void callback_expression_field(GtkWidget *widget, gpointer data);
void callback_cancel_button(GtkWidget *widget, gpointer data);

/**
 *  @struct _FilterViewerDataLine
 *
 *  @brief Defines a simple expression
 *  This structures defines a simple
 *  expression whithin the main filter 
 *  viewer data
 */
struct _FilterViewerDataLine {
  int row;                            /**< row number */
  gboolean visible;                   /**< visible state */
  GtkWidget *f_not_op_box;            /**< '!' operator (GtkComboBox) */
  GtkWidget *f_logical_op_box;        /**< '&,|,^' operators (GtkComboBox) */
  GtkWidget *f_field_box;             /**< field types (GtkComboBox) */
  GtkWidget *f_math_op_box;           /**< '>,>=,<,<=,=,!=' operators (GtkComboBox) */
  GtkWidget *f_value_field;           /**< expression's value (GtkComboBox) */
};

/**
 *  @struct _FilterViewerData
 *  
 *  @brief Main structure of gui filter
 *  Main struct for the filter gui module
 */
struct _FilterViewerData {
  LttvPlugin *plugin;                   /**< Plugin on which we interact. */

  GtkWidget *f_window;                  /**< filter window */
  
  GtkWidget *f_main_box;                /**< main container */

  GtkWidget *f_expression_field;        /**< entire expression (GtkEntry) */
  GtkWidget *f_process_button;          /**< process expression button (GtkButton) */

  GtkWidget *f_logical_op_junction_box; /**< linking operator box (GtkComboBox) */

  int rows;                             /**< number of rows */
  GPtrArray *f_lines;                   /**< array of FilterViewerDataLine */

  GPtrArray *f_not_op_options;          /**< array of operators types for not_op box */
  GPtrArray *f_logical_op_options;      /**< array of operators types for logical_op box */
  GPtrArray *f_field_options;           /**< array of field types for field box */
  GPtrArray *f_math_op_options;         /**< array of operators types for math_op box */
  
  GtkWidget *f_add_button;              /**< add expression to current expression (GtkButton) */
  GtkWidget *f_cancel_button;           /**< cancel and close dialog (GtkButton) */
 
};

/**
 *  @fn GtkWidget* guifilter_get_widget(FilterViewerData*)
 * 
 *  This function returns the current main widget 
 *  used by this module
 *  @param fvd the module struct
 *  @return The main widget
 */
GtkWidget*
guifilter_get_widget(FilterViewerData *fvd)
{
  return fvd->f_window;
}

/**
 *  @fn FilterViewerData* gui_filter(Tab*)
 * 
 *  Constructor is used to create FilterViewerData data structure.
 *  @param tab The tab structure used by the widget
 *  @return The Filter viewer data created.
 */
FilterViewerData*
gui_filter(LttvPlugin *plugin)
{
  g_debug("filter::gui_filter()");

  unsigned i;

  FilterViewerData* fvd = g_new(FilterViewerData,1);

  fvd->plugin = plugin;

//  lttvwindow_register_traceset_notify(fvd->tab,
//                                      filter_traceset_changed,
//                                     filter_viewer_data);
//  request_background_data(filter_viewer_data);
 
  /*
   * Initiating items for
   * combo boxes
   */
  fvd->f_not_op_options = g_ptr_array_new();
  g_ptr_array_add(fvd->f_not_op_options,(gpointer) g_string_new(""));
  g_ptr_array_add(fvd->f_not_op_options,(gpointer) g_string_new("!"));
  
  fvd->f_logical_op_options = g_ptr_array_new(); //g_array_new(FALSE,FALSE,sizeof(gchar));
  g_ptr_array_add(fvd->f_logical_op_options,(gpointer) g_string_new(""));
  g_ptr_array_add(fvd->f_logical_op_options,(gpointer) g_string_new("&"));
  g_ptr_array_add(fvd->f_logical_op_options,(gpointer) g_string_new("|"));
  g_ptr_array_add(fvd->f_logical_op_options,(gpointer) g_string_new("!"));
  g_ptr_array_add(fvd->f_logical_op_options,(gpointer) g_string_new("^"));

  fvd->f_field_options = g_ptr_array_new(); //g_array_new(FALSE,FALSE,16);
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new(""));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("event.name"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("event.subname"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("event.category"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("event.time"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("event.tsc"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("event.target_pid"));
  /*
   * TODO: Add core.xml fields here !
   */
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("channel.name"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("trace.name"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.process_name"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.thread_brand"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.pid"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.ppid"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.creation_time"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.insertion_time"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.execution_mode"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.execution_submode"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.process_status"));
  g_ptr_array_add(fvd->f_field_options,(gpointer) g_string_new("state.cpu"));
  
  fvd->f_math_op_options = g_ptr_array_new(); //g_array_new(FALSE,FALSE,7);  
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new(""));
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new("="));
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new("!="));
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new("<"));
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new("<="));
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new(">"));
  g_ptr_array_add(fvd->f_math_op_options,(gpointer) g_string_new(">="));
  

  fvd->f_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title(GTK_WINDOW(fvd->f_window), "LTTV Filter");
  gtk_window_set_transient_for(GTK_WINDOW(fvd->f_window),
      GTK_WINDOW(gtk_widget_get_toplevel(GTK_WIDGET(fvd->plugin->top_widget))));
  gtk_window_set_destroy_with_parent(GTK_WINDOW(fvd->f_window), TRUE);
  gtk_window_set_resizable(GTK_WINDOW(fvd->f_window), FALSE);

  /* 
   * Initiating GtkTable layout 
   * starts with 2 rows and 5 columns and 
   * expands when expressions added
   */
  fvd->f_main_box = gtk_table_new(3,7,FALSE);
  gtk_table_set_row_spacings(GTK_TABLE(fvd->f_main_box),5);
  gtk_table_set_col_spacings(GTK_TABLE(fvd->f_main_box),5);
  
  gtk_container_add(GTK_CONTAINER(fvd->f_window), GTK_WIDGET(fvd->f_main_box));
  
  /*
   *  First half of the filter window
   *  - textual entry of filter expression
   *  - processing button
   */
  fvd->f_expression_field = gtk_entry_new(); //gtk_scrolled_window_new (NULL, NULL);
  g_signal_connect (G_OBJECT(fvd->f_expression_field),
      "key-press-event", G_CALLBACK (callback_enter_check), (gpointer)fvd);
//  gtk_entry_set_text(GTK_ENTRY(fvd->f_expression_field),"state.cpu>0");
  gtk_widget_show (fvd->f_expression_field);

  g_signal_connect (G_OBJECT (fvd->f_expression_field), "changed",
      G_CALLBACK (callback_expression_field), (gpointer) fvd); 

  fvd->f_process_button = gtk_button_new_with_label("Process");
  gtk_widget_show (fvd->f_process_button);
  
  g_signal_connect (G_OBJECT (fvd->f_process_button), "clicked",
      G_CALLBACK (callback_process_button), (gpointer) fvd); 
  
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvd->f_expression_field,0,6,0,1,GTK_FILL,GTK_FILL,0,0);
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvd->f_process_button,6,7,0,1,GTK_FILL,GTK_FILL,0,0);


  
  /*
   *  Second half of the filter window
   *  - combo boxes featuring filtering options added to the expression
   */
  fvd->f_add_button = gtk_button_new_with_label("Add Expression");
  gtk_widget_show (fvd->f_add_button);

  g_signal_connect (G_OBJECT (fvd->f_add_button), "clicked",
      G_CALLBACK (callback_add_button), (gpointer) fvd);
  
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvd->f_add_button,6,7,2,3,GTK_FILL,GTK_FILL,0,0);

  fvd->f_cancel_button = gtk_button_new_with_label("Cancel");
  gtk_widget_show (fvd->f_cancel_button);
  g_signal_connect (G_OBJECT (fvd->f_cancel_button), "clicked",
      G_CALLBACK (callback_cancel_button), (gpointer) fvd);

  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvd->f_cancel_button,6,7,1,2,GTK_FILL,GTK_FILL,0,0);
  
  fvd->f_logical_op_junction_box = gtk_combo_box_new_text();
  for(i=0;i<fvd->f_logical_op_options->len;i++) {
    GString* s = g_ptr_array_index(fvd->f_logical_op_options,i);
    gtk_combo_box_append_text(GTK_COMBO_BOX(fvd->f_logical_op_junction_box), s->str); 
  }
  gtk_combo_box_set_active(GTK_COMBO_BOX(fvd->f_logical_op_junction_box),0);
  
  //gtk_widget_show(fvd->f_logical_op_box);
 
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvd->f_logical_op_junction_box,0,1,1,2,GTK_SHRINK,GTK_FILL,0,0);

  gtk_container_set_border_width(GTK_CONTAINER(fvd->f_main_box), 1);
  
  /* initialize a new line */
  fvd->f_lines = g_ptr_array_new();
  fvd->rows = 1;
  FilterViewerDataLine* fvdl = gui_filter_add_line(fvd);
  g_ptr_array_add(fvd->f_lines,(gpointer) fvdl);
  
  /* 
   * show main container 
   */
  gtk_widget_show(fvd->f_main_box);
  gtk_widget_show(fvd->f_window);
  
  
  g_object_set_data_full(
      G_OBJECT(guifilter_get_widget(fvd)),
      "filter_viewer_data",
      fvd,
      (GDestroyNotify)gui_filter_destructor);

  g_filter_list = g_slist_append(
      g_filter_list,
      fvd);
  
  return fvd;
}

/**
 *  @fn FilterViewerDataLine* gui_filter_add_line(FilterViewerData*)
 * 
 *  Adds a filter option line on the module tab
 *  @param fvd The filter module structure 
 *  @return The line structure
 */
FilterViewerDataLine*
gui_filter_add_line(FilterViewerData* fvd) {

  FilterViewerDataLine* fvdl = g_new(FilterViewerDataLine,1);

  unsigned i;
  fvdl->row = fvd->rows;
  fvdl->visible = TRUE;

  fvdl->f_not_op_box = gtk_combo_box_new_text();
  for(i=0;i<fvd->f_not_op_options->len;i++) {
    GString* s = g_ptr_array_index(fvd->f_not_op_options,i);
    gtk_combo_box_append_text(GTK_COMBO_BOX(fvdl->f_not_op_box), s->str);
  }

  fvdl->f_field_box = gtk_combo_box_new_text();
  for(i=0;i<fvd->f_field_options->len;i++) {
    GString* s = g_ptr_array_index(fvd->f_field_options,i);
//    g_print("String field: %s\n",s->str);
    gtk_combo_box_append_text(GTK_COMBO_BOX(fvdl->f_field_box), s->str);
  }
  
  fvdl->f_math_op_box = gtk_combo_box_new_text();
  for(i=0;i<fvd->f_math_op_options->len;i++) {
    GString* s = g_ptr_array_index(fvd->f_math_op_options,i);
    gtk_combo_box_append_text(GTK_COMBO_BOX(fvdl->f_math_op_box), s->str); 
  }
  
  fvdl->f_value_field = gtk_entry_new();
 
  fvdl->f_logical_op_box = gtk_combo_box_new_text();
  for(i=0;i<fvd->f_logical_op_options->len;i++) {
    GString* s = g_ptr_array_index(fvd->f_logical_op_options,i);
    gtk_combo_box_append_text(GTK_COMBO_BOX(fvdl->f_logical_op_box), s->str); 
  }
  gtk_widget_set_events(fvdl->f_logical_op_box,
      GDK_ENTER_NOTIFY_MASK |
      GDK_LEAVE_NOTIFY_MASK |
      GDK_FOCUS_CHANGE_MASK);

  g_signal_connect (G_OBJECT (fvdl->f_logical_op_box), "changed",
    G_CALLBACK (callback_logical_op_box), (gpointer) fvd); 

  gui_filter_line_reset(fvdl);
  gui_filter_line_set_visible(fvdl,TRUE);
  
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvdl->f_not_op_box,0,1,fvd->rows+1,fvd->rows+2,GTK_SHRINK,GTK_FILL,0,0);
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvdl->f_field_box,1,3,fvd->rows+1,fvd->rows+2,GTK_SHRINK,GTK_FILL,0,0);
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvdl->f_math_op_box,3,4,fvd->rows+1,fvd->rows+2,GTK_SHRINK,GTK_FILL,0,0);
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvdl->f_value_field,4,5,fvd->rows+1,fvd->rows+2,GTK_SHRINK,GTK_FILL,0,0);
  gtk_table_attach( GTK_TABLE(fvd->f_main_box),fvdl->f_logical_op_box,5,6,fvd->rows+1,fvd->rows+2,GTK_SHRINK,GTK_FILL,0,0);
 
  return fvdl;
}

/**
 *  @fn void gui_filter_line_set_visible(FilterViewerDataLine*,gboolean)
 *
 *  Change visible state of current FilterViewerDataLine
 *  @param fvdl pointer to the current FilterViewerDataLine
 *  @param v TRUE: sets visible, FALSE: sets invisible
 */
void 
gui_filter_line_set_visible(FilterViewerDataLine *fvdl, gboolean v) {

  fvdl->visible = v;
  if(v) {
    gtk_widget_show(fvdl->f_not_op_box);
    gtk_widget_show(fvdl->f_field_box);
    gtk_widget_show(fvdl->f_math_op_box);
    gtk_widget_show(fvdl->f_value_field);
    gtk_widget_show(fvdl->f_logical_op_box);
  } else {
    gtk_widget_hide(fvdl->f_not_op_box);
    gtk_widget_hide(fvdl->f_field_box);
    gtk_widget_hide(fvdl->f_math_op_box);
    gtk_widget_hide(fvdl->f_value_field);
    gtk_widget_hide(fvdl->f_logical_op_box);
 } 
  
}

/**
 *  @fn void gui_filter_line_reset(FilterViewerDataLine*)
 *
 *  Sets selections of all boxes in current FilterViewerDataLine 
 *  to default value (0)
 *  @param fvdl pointer to current FilterViewerDataLine
 */
void 
gui_filter_line_reset(FilterViewerDataLine *fvdl) {

  gtk_combo_box_set_active(GTK_COMBO_BOX(fvdl->f_not_op_box),0);
  gtk_combo_box_set_active(GTK_COMBO_BOX(fvdl->f_field_box),0);
  gtk_combo_box_set_active(GTK_COMBO_BOX(fvdl->f_math_op_box),0);
  gtk_entry_set_text(GTK_ENTRY(fvdl->f_value_field),"");
  gtk_combo_box_set_active(GTK_COMBO_BOX(fvdl->f_logical_op_box),0);
}

/**
 *  @fn void gui_filter_destructor(FilterViewerData*)
 * 
 *  Destructor for the filter gui module
 *  @param fvd The module structure
 */
void
gui_filter_destructor(FilterViewerData *fvd)
{
  /* May already been done by GTK window closing */
  if(GTK_IS_WIDGET(guifilter_get_widget(fvd))){
    g_info("widget still exists");
  }
//  if(tab != NULL) {
//    lttvwindow_unregister_traceset_notify(fvd->tab,
//                                          filter_traceset_changed,
//                                          filter_viewer_data);
//  }
  lttvwindowtraces_background_notify_remove(fvd);
  
  g_filter_list = g_slist_remove(g_filter_list, fvd);
 
  g_free(fvd);
}


/**
 *  @fn GtkWidget* h_guifilter(Tab*)
 * 
 *  Filter Module's constructor hook
 *
 *  This constructor is given as a parameter to the menuitem and toolbar button
 *  registration. It creates the list.
 *  @param obj Object to interact with.
 *  @return The widget created.
 */
GtkWidget *
h_guifilter(LttvPlugin *plugin)
{
	gui_filter(plugin);

	/* TODO ybrosseau 2011-02-04: We should probably return a widget here */
	return NULL;
}

/**
 *  @fn static void init()
 * 
 *  This function initializes the Filter Viewer functionnality through the
 *  gtkTraceSet API.
 */
static void init() {

  lttvwindow_register_constructor("guifilter",
                                  "/",
                                  "Insert Filter Module",
                                  hGuiFilterInsert_xpm,
                                  "Insert Filter Module",
                                  h_guifilter);
}

/**
 *  @fn void filter_destroy_walk(gpointer,gpointer)
 * 
 *  Initiate the destruction of the current gui module
 *  on the GTK Interface
 */
void 
filter_destroy_walk(gpointer data, gpointer user_data)
{
  FilterViewerData *fvd = (FilterViewerData*)data;

  g_debug("CFV.c : filter_destroy_walk, %p", fvd);

  /* May already have been done by GTK window closing */
  if(GTK_IS_WIDGET(guifilter_get_widget(fvd)))
    gtk_widget_destroy(guifilter_get_widget(fvd));
}

/**
 *  @fn static void destroy()
 *  @brief plugin's destroy function
 *
 *  This function releases the memory reserved by the module and unregisters
 *  everything that has been registered in the gtkTraceSet API.
 */
static void destroy() {
 
  g_slist_foreach(g_filter_list, filter_destroy_walk, NULL );
  
  lttvwindow_unregister_constructor(h_guifilter);
  
}

/**
 *  @fn void callback_process_button(GtkWidget*,gpointer)
 * 
 *  The Process Button callback function
 *  @param widget The Button widget passed to the callback function
 *  @param data Data sent along with the callback function
 */
void 
callback_process_button(GtkWidget *widget, gpointer data) {

  g_debug("callback_process_button(): Processing expression");
  
  FilterViewerData *fvd = (FilterViewerData*)data;
  LttvFilter* filter;

  if(strlen(gtk_entry_get_text(GTK_ENTRY(fvd->f_expression_field))) !=0) {
    filter = lttv_filter_new();
    GString* s = g_string_new(gtk_entry_get_text(GTK_ENTRY(fvd->f_expression_field)));
    lttv_filter_append_expression(filter,s->str);
    g_string_free(s,TRUE);
  } else {
    filter = NULL;
  }
  /* Remove the old filter if present */
  //g_object_set_data_full(fvd->obj, "filter", filter,
  //                      (GDestroyNotify)lttv_filter_destroy);
  //g_object_notify(fvd->obj, "filter");
  lttv_plugin_update_filter(fvd->plugin, filter);
}

/**
 *  @fn void callback_cancel_button(GtkWidget*,gpointer)
 * 
 *  The Cancel Button callback function
 *  @param widget The Button widget passed to the callback function
 *  @param data Data sent along with the callback function
 */
void 
callback_cancel_button(GtkWidget *widget, gpointer data) {

  FilterViewerData *fvd = (FilterViewerData*)data;
  gtk_widget_destroy(fvd->f_window);
}

gboolean callback_enter_check(GtkWidget *widget,
    GdkEventKey *event,
    gpointer user_data)
{
 g_debug("typed : %x", event->keyval);
 switch(event->keyval) {
   case GDK_Return:
   case GDK_KP_Enter:
   case GDK_ISO_Enter:
   case GDK_3270_Enter:
     callback_process_button(widget, user_data);
     break;
   default:
     break;
 }
 return FALSE;
}

/**
 *  @fn void callback_expression_field(GtkWidget*,gpointer)
 * 
 *  The Add Button callback function
 *  @param widget The Button widget passed to the callback function
 *  @param data Data sent along with the callback function
 */
void 
callback_expression_field(GtkWidget *widget, gpointer data) {
  
  FilterViewerData *fvd = (FilterViewerData*)data;

  if(strlen(gtk_entry_get_text(GTK_ENTRY(fvd->f_expression_field))) !=0) {
    gtk_widget_show(fvd->f_logical_op_junction_box);
  } else {
    gtk_widget_hide(fvd->f_logical_op_junction_box);
  }
}


/**
 *  @fn void callback_add_button(GtkWidget*,gpointer)
 * 
 *  The Add Button callback function
 *  @param widget The Button widget passed to the callback function
 *  @param data Data sent along with the callback function
 */
void 
callback_add_button(GtkWidget *widget, gpointer data) {

  g_debug("callback_add_button(): processing simple expressions");

  unsigned i;
  
  FilterViewerData *fvd = (FilterViewerData*)data;
  FilterViewerDataLine *fvdl = NULL;
  GString* a_filter_string = g_string_new("");

  /*
   * adding linking operator to 
   * string
   */
  GString* s;
  s = g_ptr_array_index(fvd->f_logical_op_options,gtk_combo_box_get_active(GTK_COMBO_BOX(fvd->f_logical_op_junction_box)));
  a_filter_string = g_string_append(a_filter_string,s->str);
  gtk_combo_box_set_active(GTK_COMBO_BOX(fvd->f_logical_op_junction_box),0);

  /* begin expression */
  a_filter_string = g_string_append_c(a_filter_string,'(');

  /*
   * For each simple expression, add the resulting string 
   * to the filter string
   *
   * Each simple expression takes the following schema
   * [not operator '!',' '] [field type] [math operator '<','<=','>','>=','=','!='] [value]
   */
  for(i=0;i<fvd->f_lines->len;i++) {
    fvdl = (FilterViewerDataLine*)g_ptr_array_index(fvd->f_lines,i);
 
    s = g_ptr_array_index(fvd->f_not_op_options,gtk_combo_box_get_active(GTK_COMBO_BOX(fvdl->f_not_op_box)));
    a_filter_string = g_string_append(a_filter_string,s->str);
    
    s = g_ptr_array_index(fvd->f_field_options,gtk_combo_box_get_active(GTK_COMBO_BOX(fvdl->f_field_box)));
    a_filter_string = g_string_append(a_filter_string,s->str);
    
    s = g_ptr_array_index(fvd->f_math_op_options,gtk_combo_box_get_active(GTK_COMBO_BOX(fvdl->f_math_op_box)));
    a_filter_string = g_string_append(a_filter_string,s->str);
    
    a_filter_string = g_string_append(a_filter_string,gtk_entry_get_text(GTK_ENTRY(fvdl->f_value_field)));
    
    s = g_ptr_array_index(fvd->f_logical_op_options,gtk_combo_box_get_active(GTK_COMBO_BOX(fvdl->f_logical_op_box)));
    a_filter_string = g_string_append(a_filter_string,s->str);
    
    /*
     * resetting simple expression lines
     */
    gui_filter_line_reset(fvdl);
    if(i) gui_filter_line_set_visible(fvdl,FALSE); // Only keep the first line
  }

  /* end expression */
  a_filter_string = g_string_append_c(a_filter_string,')');

  g_string_prepend(a_filter_string,gtk_entry_get_text(GTK_ENTRY(fvd->f_expression_field)));
  gtk_entry_set_text(GTK_ENTRY(fvd->f_expression_field),a_filter_string->str);
  
}

/**
 *  @fn void callback_logical_op_box(GtkWidget*,gpointer)
 * 
 *  The logical op box callback function 
 *  @param widget The Button widget passed to the callback function
 *  @param data Data sent along with the callback function
 */
void 
callback_logical_op_box(GtkWidget *widget, gpointer data) {
 
  g_debug("callback_logical_op_box(): adding new simple expression");

  FilterViewerData *fvd = (FilterViewerData*)data;
  FilterViewerDataLine *fvdl = NULL;
  
  int i;
  for(i=0;i<fvd->f_lines->len;i++) {
    fvdl = (FilterViewerDataLine*)g_ptr_array_index(fvd->f_lines,i);
    if(fvdl->f_logical_op_box == widget) {
      if(gtk_combo_box_get_active(GTK_COMBO_BOX(fvdl->f_logical_op_box)) == 0) return;
      if(i==fvd->f_lines->len-1) {  /* create a new line */
        fvd->rows++;
        FilterViewerDataLine* fvdl2 = gui_filter_add_line(fvd);
        g_ptr_array_add(fvd->f_lines,(gpointer) fvdl2);
      } else {
        FilterViewerDataLine *fvdl2 = (FilterViewerDataLine*)g_ptr_array_index(fvd->f_lines,i+1);
        if(!fvdl2->visible) gui_filter_line_set_visible(fvdl2,TRUE); 
      }
    }
  }
  
}

LTTV_MODULE("guifilter", "Filter window", \
    "Graphical module that let user specify their filtering options", \
    init, destroy, "lttvwindow")