PIKApp/plug-ins/script-fu/console/script-fu-console-history.c

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2023-09-26 00:35:21 +02:00
/* PIKA - Photo and Image Kooker Application
* a rebranding of The GNU Image Manipulation Program (created with heckimp)
* A derived work which may be trivial. However, any changes may be (C)2023 by Aldercone Studio
*
* Original copyright, applying to most contents (license remains unchanged):
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* 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 3 of the License, 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, see <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "libpika/pika.h"
#include "script-fu-console-history.h"
static gint console_history_tail_position (CommandHistory *self);
static GStrv console_history_to_strv (CommandHistory *self);
/* CommandHistory
*
* Not a true class, just a struct with methods.
* Does not inherit GObject.
*
* Is a model that affects a view of the "console history."
* The model is a sequence of ExecutedCommands.
* The sequence is a time-ordered queue.
* You can only append to the end, called the tail.
* An ExecutedCommand does not contain the result of interpretation,
* only the string that was interpreted.
*
* The sequence is finite.
* When you append to the tail,
* commands might be discarded from the head.
*
* Has a cursor.
* You can only get the command at the cursor.
* The user scrolling through the history moves the cursor.
* This scrolling is arrow keys in the editor pane,
* (not scroll bars in the history view pane.)
* See the main console logic:
* when user hits arrow keys in the editor,
* move cursor in the history, get the command at the cursor,
* and display it in the editor, ready to execute.
*
* A CommandHistory is a model,
* but there is also a distinct TotalHistory model for a scrolling view of the history
* (e.g. a GtkTextBuffer model for a GtkTextView.)
*
* CommandHistory <-supersets- TotalHistory <-views- ConsoleView
*
* TotalHistory contains more than the commands in CommandHistory.
* TotalHistory contains e.g. splash, prompts, and interpretation results.
*
* !!! Self does not currently write TotalHistory;
* The main console logic writes TotalHistory,
*
* CommandHistory is persistent across sessions of the ScriptFu Console,
* and across sessions of Pika.
* When the SFConsole starts, the TotalHistory,
* is just the CommandHistory, without results of eval.
* Old results are not meaningful since the environment changed.
* Specifically, a new session of SFConsole has a new initialized interpreter.
* Similarly, when the user closes the console,
* only the CommandHistory is saved as settings.
*/
void
console_history_init (CommandHistory *self)
{
self->model = g_list_append (self->model, NULL);
self->model_len = 1;
self->model_max = 100;
}
/* Store the command in tail of CommandHistory.
* The tail is the most recent added element, which was created prior by new_tail.
*
* @commmand transfer full
*
* !!! The caller is executing the command.
* The caller updates TotalHistory, with a prompt string and the command string.
* Self does not update TotalHistory, the model of the view.
*/
void
console_history_set_tail (CommandHistory *self,
const gchar *command)
{
GList *list;
list = g_list_nth (self->model,
console_history_tail_position (self));
if (list->data)
g_free (list->data);
/* Discarding const. */
list->data = (gpointer) command;
}
/* Remove the head of the history and free its string.
*
* GList doesn't have such a direct method.
* Search web to find this solution.
* !!! g_list_remove does not free the data of the removed element.
*
* Remove the element whose data (a string)
* matches the data of the first element.
* Then free the data of the first element.
*/
static void
console_history_remove_head (CommandHistory *self)
{
gpointer * data;
g_return_if_fail (self->model != NULL);
data = self->model->data;
self->model = g_list_remove (self->model, data);
g_free (data);
}
/* Append NULL string at tail of CommandHistory.
* Prune head when max exceeded, freeing the string.
* Position the cursor at last element.
*/
void
console_history_new_tail (CommandHistory *self)
{
self->model = g_list_append (self->model, NULL);
if (self->model_len == self->model_max)
{
console_history_remove_head (self);
}
else
{
self->model_len++;
}
self->model_cursor = console_history_tail_position (self);
}
void
console_history_cursor_to_tail (CommandHistory *self)
{
self->model_cursor = console_history_tail_position (self);
}
gboolean
console_history_is_cursor_at_tail (CommandHistory *self)
{
return self->model_cursor == console_history_tail_position (self);
}
void
console_history_move_cursor (CommandHistory *self,
gint direction)
{
self->model_cursor += direction;
/* Clamp cursor in range [0, model_len-1] */
if (self->model_cursor < 0)
self->model_cursor = 0;
if (self->model_cursor >= self->model_len)
self->model_cursor = self->model_len - 1;
}
const gchar *
console_history_get_at_cursor (CommandHistory *self)
{
return g_list_nth (self->model, self->model_cursor)->data;
}
/* Methods for persisting history as a setting. */
/* Return a GStrv of the history from settings.
* The Console knows how to put GStrv to both models!
*
* !!! Handle attack on settings file.
* The returned cardinality of the set of strings
* may be zero or very many.
* Elsewhere ensure we don't overflow models.
*/
GStrv
console_history_from_settings (CommandHistory *self,
PikaProcedureConfig *config)
{
GStrv in_history;
/* Get aux arg from property of config. */
g_object_get (config,
"history", &in_history,
NULL);
return in_history;
}
void
console_history_to_settings (CommandHistory *self,
PikaProcedureConfig *config)
{
GStrv out_history;
out_history = console_history_to_strv (self);
/* set an aux arg in config. */
g_object_set (config,
"history", out_history,
NULL);
}
/* Return history model as GStrv.
* Converts from interal list into a string array.
*
* !!! The exported history may have a tail
* which is user's edits to the command line,
* that the user never evaluated.
* Exported history does not have an empty tail.
*
* Caller must g_strfreev the returned GStrv.
*/
static GStrv
console_history_to_strv (CommandHistory *self)
{
GStrv history_strv;
GStrvBuilder *builder;
builder = g_strv_builder_new ();
/* Order is earliest first. */
for (GList *l = self->model; l != NULL; l = l->next)
{
/* Don't write an empty pre-allocated tail. */
if (l->data != NULL)
g_strv_builder_add (builder, l->data);
}
history_strv = g_strv_builder_end (builder);
g_strv_builder_unref (builder);
return history_strv;
}
static gint
console_history_tail_position (CommandHistory *self)
{
return g_list_length (self->model) - 1;
}