Convert observers to C++

This converts observers from using a special source-generating script
to be plain C++.  This version of the patch takes advantage of C++11
by using std::function and variadic templates; incorporates Pedro's
patches; and renames the header file to "observable.h" (this change
eliminates the need for a clean rebuild).

Note that Pedro's patches used a template lambda in tui-hooks.c, but
this failed to compile on some buildbot instances (presumably due to
differing C++ versions); I replaced this with an ordinary template
function.

Regression tested on the buildbot.

gdb/ChangeLog
2018-03-19  Pedro Alves  <palves@redhat.com>
	    Tom Tromey  <tom@tromey.com>

	* unittests/observable-selftests.c: New file.
	* common/observable.h: New file.
	* observable.h: New file.
	* ada-lang.c, ada-tasks.c, agent.c, aix-thread.c, annotate.c,
	arm-tdep.c, auto-load.c, auxv.c, break-catch-syscall.c,
	breakpoint.c, bsd-uthread.c, cli/cli-interp.c, cli/cli-setshow.c,
	corefile.c, dummy-frame.c, event-loop.c, event-top.c, exec.c,
	extension.c, frame.c, gdbarch.c, guile/scm-breakpoint.c,
	infcall.c, infcmd.c, inferior.c, inflow.c, infrun.c, jit.c,
	linux-tdep.c, linux-thread-db.c, m68klinux-tdep.c,
	mi/mi-cmd-break.c, mi/mi-interp.c, mi/mi-main.c, objfiles.c,
	ppc-linux-nat.c, ppc-linux-tdep.c, printcmd.c, procfs.c,
	python/py-breakpoint.c, python/py-finishbreakpoint.c,
	python/py-inferior.c, python/py-unwind.c, ravenscar-thread.c,
	record-btrace.c, record-full.c, record.c, regcache.c, remote.c,
	riscv-tdep.c, sol-thread.c, solib-aix.c, solib-spu.c, solib.c,
	spu-multiarch.c, spu-tdep.c, stack.c, symfile-mem.c, symfile.c,
	symtab.c, thread.c, top.c, tracepoint.c, tui/tui-hooks.c,
	tui/tui-interp.c, valops.c: Update all users.
	* tui/tui-hooks.c (tui_bp_created_observer)
	(tui_bp_deleted_observer, tui_bp_modified_observer)
	(tui_inferior_exit_observer, tui_before_prompt_observer)
	(tui_normal_stop_observer, tui_register_changed_observer):
	Remove.
	(tui_observers_token): New global.
	(attach_or_detach, tui_attach_detach_observers): New functions.
	(tui_install_hooks, tui_remove_hooks): Use
	tui_attach_detach_observers.
	* record-btrace.c (record_btrace_thread_observer): Remove.
	(record_btrace_thread_observer_token): New global.
	* observer.sh: Remove.
	* observer.c: Rename to observable.c.
	* observable.c (namespace gdb_observers): Define new objects.
	(observer_debug): Move into gdb_observers namespace.
	(struct observer, struct observer_list, xalloc_observer_list_node)
	(xfree_observer_list_node, generic_observer_attach)
	(generic_observer_detach, generic_observer_notify): Remove.
	(_initialize_observer): Update.
	Don't include observer.inc.
	* Makefile.in (generated_files): Remove observer.h, observer.inc.
	(clean mostlyclean): Likewise.
	(observer.h, observer.inc): Remove targets.
	(SUBDIR_UNITTESTS_SRCS): Add observable-selftests.c.
	(COMMON_SFILES): Use observable.c, not observer.c.
	* .gitignore: Remove observer.h.

gdb/doc/ChangeLog
2018-03-19  Tom Tromey  <tom@tromey.com>

	* observer.texi: Remove.

gdb/testsuite/ChangeLog
2018-03-19  Tom Tromey  <tom@tromey.com>

	* gdb.gdb/observer.exp: Remove.

1 files changed, 135 insertions, 0 deletions

diff --git a/gdb/unittests/observable-selftests.c b/gdb/unittests/observable-selftests.c
new file mode 100644
index 0000000..6f2f7e8
--- /dev/null
+++ b/gdb/unittests/observable-selftests.c
@@ -0,0 +1,135 @@
+/* Self tests for gdb::observers, 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/>.  */
+
+#include "defs.h"
+#include "selftest.h"
+#include "common/observable.h"
+
+namespace selftests {
+namespace observers {
+
+gdb::observers::observable<int> test_notification ("test_notification");
+
+static int test_first_observer = 0;
+static int test_second_observer = 0;
+static int test_third_observer = 0;
+
+static void
+test_first_notification_function (int arg)
+{
+  test_first_observer++;
+}
+
+static void
+test_second_notification_function (int arg)
+{
+  test_second_observer++;
+}
+
+static void
+test_third_notification_function (int arg)
+{
+  test_third_observer++;
+}
+
+static void
+notify_check_counters (int one, int two, int three)
+{
+  /* Reset.  */
+  test_first_observer = 0;
+  test_second_observer = 0;
+  test_third_observer = 0;
+  /* Notify.  */
+  test_notification.notify (0);
+  /* Check.  */
+  SELF_CHECK (one == test_first_observer);
+  SELF_CHECK (two == test_second_observer);
+  SELF_CHECK (three == test_third_observer);
+}
+
+static void
+run_tests ()
+{
+  /* First, try sending a notification without any observer
+     attached.  */
+  notify_check_counters (0, 0, 0);
+
+  const gdb::observers::token token1, token2, token3;
+
+  /* Now, attach one observer, and send a notification.  */
+  test_notification.attach (&test_second_notification_function, token2);
+  notify_check_counters (0, 1, 0);
+
+  /* Remove the observer, and send a notification.  */
+  test_notification.detach (token2);
+  notify_check_counters (0, 0, 0);
+
+  /* With a new observer.  */
+  test_notification.attach (&test_first_notification_function, token1);
+  notify_check_counters (1, 0, 0);
+
+  /* With 2 observers.  */
+  test_notification.attach (&test_second_notification_function, token2);
+  notify_check_counters (1, 1, 0);
+
+  /* With 3 observers.  */
+  test_notification.attach (&test_third_notification_function, token3);
+  notify_check_counters (1, 1, 1);
+
+  /* Remove middle observer.  */
+  test_notification.detach (token2);
+  notify_check_counters (1, 0, 1);
+
+  /* Remove first observer.  */
+  test_notification.detach (token1);
+  notify_check_counters (0, 0, 1);
+
+  /* Remove last observer.  */
+  test_notification.detach (token3);
+  notify_check_counters (0, 0, 0);
+
+  /* Go back to 3 observers, and remove them in a different
+     order...  */
+  test_notification.attach (&test_first_notification_function, token1);
+  test_notification.attach (&test_second_notification_function, token2);
+  test_notification.attach (&test_third_notification_function, token3);
+  notify_check_counters (1, 1, 1);
+
+  /* Remove the third observer.  */
+  test_notification.detach (token3);
+  notify_check_counters (1, 1, 0);
+
+  /* Remove the second observer.  */
+  test_notification.detach (token2);
+  notify_check_counters (1, 0, 0);
+
+  /* Remove first observer, no more observers.  */
+  test_notification.detach (token1);
+  notify_check_counters (0, 0, 0);
+}
+
+} /* namespace observers */
+} /* namespace selftests */
+
+void
+_initialize_observer_selftest ()
+{
+  selftests::register_test ("gdb::observers",
+			    selftests::observers::run_tests);
+}