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/* Thread command's finish-state machine, for GDB, the GNU debugger.
Copyright (C) 2015-2024 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/>. */
#ifndef THREAD_FSM_H
#define THREAD_FSM_H
#include "mi/mi-common.h"
struct return_value_info;
struct thread_fsm_ops;
struct type;
struct value;
/* The captured function return value/type and its position in the
value history. */
struct return_value_info
{
/* The captured return value. May be NULL if we weren't able to
retrieve it. See get_return_value. */
struct value *value;
/* The return type. In some cases, we'll not be able extract the
return value, but we always know the type. */
struct type *type;
/* If we captured a value, this is the value history index. */
int value_history_index;
};
/* A thread finite-state machine structure contains the necessary info
and callbacks to manage the state machine protocol of a thread's
execution command. */
struct thread_fsm
{
explicit thread_fsm (struct interp *cmd_interp)
: command_interp (cmd_interp)
{
}
/* The destructor. This should simply free heap allocated data
structures. Cleaning up target resources (like, e.g.,
breakpoints) should be done in the clean_up method. */
virtual ~thread_fsm () = default;
DISABLE_COPY_AND_ASSIGN (thread_fsm);
/* Called to clean up target resources after the FSM. E.g., if the
FSM created internal breakpoints, this is where they should be
deleted. */
virtual void clean_up (struct thread_info *thread)
{
}
/* Called after handle_inferior_event decides the target is done
(that is, after stop_waiting). The FSM is given a chance to
decide whether the command is done and thus the target should
stop, or whether there's still more to do and thus the thread
should be re-resumed. This is a good place to cache target data
too. For example, the "finish" command saves the just-finished
function's return value here. */
virtual bool should_stop (struct thread_info *thread) = 0;
/* If this FSM saved a function's return value, you can use this
method to retrieve it. Otherwise, this returns NULL. */
virtual struct return_value_info *return_value ()
{
return nullptr;
}
enum async_reply_reason async_reply_reason ()
{
/* If we didn't finish, then the stop reason must come from
elsewhere. E.g., a breakpoint hit or a signal intercepted. */
gdb_assert (finished_p ());
return do_async_reply_reason ();
}
/* Whether the stop should be notified to the user/frontend. */
virtual bool should_notify_stop ()
{
return true;
}
void set_finished ()
{
finished = true;
}
bool finished_p () const
{
return finished;
}
/* The interpreter that issued the execution command that caused
this thread to resume. If the top level interpreter is MI/async,
and the execution command was a CLI command (next/step/etc.),
we'll want to print stop event output to the MI console channel
(the stepped-to line, etc.), as if the user entered the execution
command on a real GDB console. */
struct interp *command_interp = nullptr;
protected:
/* Whether the FSM is done successfully. */
bool finished = false;
/* The async_reply_reason that is broadcast to MI clients if this
FSM finishes successfully. */
virtual enum async_reply_reason do_async_reply_reason ()
{
gdb_assert_not_reached ("should not call async_reply_reason here");
}
};
#endif /* THREAD_FSM_H */