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Diffstat (limited to 'gdb/observer.c')
| -rw-r--r-- | gdb/observer.c | 215 |
1 files changed, 0 insertions, 215 deletions
diff --git a/gdb/observer.c b/gdb/observer.c deleted file mode 100644 index 3c0ec2a..0000000 --- a/gdb/observer.c +++ /dev/null @@ -1,215 +0,0 @@ -/* GDB Notifications to Observers. - - Copyright (C) 2003-2018 Free Software Foundation, Inc. - - This file is part of GDB. - - 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 <http://www.gnu.org/licenses/>. */ - -/* An observer is an entity who is interested in being notified when GDB - reaches certain states, or certain events occur in GDB. The entity being - observed is called the Subject. To receive notifications, the observer - attaches a callback to the subject. One subject can have several - observers. - - This file implements an internal generic low-level event notification - mechanism based on the Observer paradigm described in the book "Design - Patterns". This generic event notification mechansim is then re-used - to implement the exported high-level notification management routines - for all possible notifications. - - The current implementation of the generic observer provides support - for contextual data. This contextual data is given to the subject - when attaching the callback. In return, the subject will provide - this contextual data back to the observer as a parameter of the - callback. - - FIXME: The current support for the contextual data is only partial, - as it lacks a mechanism that would deallocate this data when the - callback is detached. This is not a problem so far, as this contextual - data is only used internally to hold a function pointer. Later on, - if a certain observer needs to provide support for user-level - contextual data, then the generic notification mechanism will need - need to be enhanced to allow the observer to provide a routine to - deallocate the data when attaching the callback. - - This file is currently maintained by hand, but the long term plan - if the number of different notifications starts growing is to create - a new script (observer.sh) that would generate this file, and the - associated documentation. */ - -#include "defs.h" -#include "observer.h" -#include "command.h" -#include "gdbcmd.h" - -static unsigned int observer_debug; -static void -show_observer_debug (struct ui_file *file, int from_tty, - struct cmd_list_element *c, const char *value) -{ - fprintf_filtered (file, _("Observer debugging is %s.\n"), value); -} - -/* The internal generic observer. */ - -typedef void (generic_observer_notification_ftype) (const void *data, - const void *args); - -struct observer -{ - generic_observer_notification_ftype *notify; - /* No memory management needed for the following field for now. */ - void *data; -}; - -/* A list of observers, maintained by the subject. A subject is - actually represented by its list of observers. */ - -struct observer_list -{ - struct observer_list *next; - struct observer *observer; -}; - -/* Allocate a struct observer_list, intended to be used as a node - in the list of observers maintained by a subject. */ - -static struct observer_list * -xalloc_observer_list_node (void) -{ - struct observer_list *node = XNEW (struct observer_list); - - node->observer = XNEW (struct observer); - return node; -} - -/* The opposite of xalloc_observer_list_node, frees the memory for - the given node. */ - -static void -xfree_observer_list_node (struct observer_list *node) -{ - xfree (node->observer); - xfree (node); -} - -/* Attach the callback NOTIFY to a SUBJECT. The DATA is also stored, - in order for the subject to provide it back to the observer during - a notification. */ - -static struct observer * -generic_observer_attach (struct observer_list **subject, - generic_observer_notification_ftype * notify, - void *data) -{ - struct observer_list *observer_list = xalloc_observer_list_node (); - - observer_list->next = *subject; - observer_list->observer->notify = notify; - observer_list->observer->data = data; - *subject = observer_list; - - return observer_list->observer; -} - -/* Remove the given OBSERVER from the SUBJECT. Once detached, OBSERVER - should no longer be used, as it is no longer valid. */ - -static void -generic_observer_detach (struct observer_list **subject, - const struct observer *observer) -{ - struct observer_list *previous_node = NULL; - struct observer_list *current_node = *subject; - - while (current_node != NULL) - { - if (current_node->observer == observer) - { - if (previous_node != NULL) - previous_node->next = current_node->next; - else - *subject = current_node->next; - xfree_observer_list_node (current_node); - return; - } - previous_node = current_node; - current_node = current_node->next; - } - - /* We should never reach this point. However, this should not be - a very serious error, so simply report a warning to the user. */ - warning (_("Failed to detach observer")); -} - -/* Send a notification to all the observers of SUBJECT. ARGS is passed to - all observers as an argument to the notification callback. */ - -static void -generic_observer_notify (struct observer_list *subject, const void *args) -{ - struct observer_list *current_node = subject; - - while (current_node != NULL) - { - (*current_node->observer->notify) (current_node->observer->data, args); - current_node = current_node->next; - } -} - - -/* The following code is only used to unit-test the observers from our - testsuite. DO NOT USE IT within observer.c (or anywhere else for - that matter)! */ - -/* If we define these variables and functions as `static', the - compiler will optimize them out. */ - -int observer_test_first_observer = 0; -int observer_test_second_observer = 0; -int observer_test_third_observer = 0; - -void -observer_test_first_notification_function (int arg) -{ - observer_test_first_observer++; -} - -void -observer_test_second_notification_function (int arg) -{ - observer_test_second_observer++; -} - -void -observer_test_third_notification_function (int arg) -{ - observer_test_third_observer++; -} - -void -_initialize_observer (void) -{ - add_setshow_zuinteger_cmd ("observer", class_maintenance, - &observer_debug, _("\ -Set observer debugging."), _("\ -Show observer debugging."), _("\ -When non-zero, observer debugging is enabled."), - NULL, - show_observer_debug, - &setdebuglist, &showdebuglist); -} - -#include "observer.inc" |