/* Inferior process information for the remote server for GDB.
  Copyright (C) 2002-2024 Free Software Foundation, Inc.

  Contributed by MontaVista Software.

  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 "gdbsupport/common-gdbthread.h"
#include "gdbsupport/common-inferior.h"
#include "gdbsupport/owning_intrusive_list.h"
#include "gdbthread.h"
#include "dll.h"

owning_intrusive_list<process_info> all_processes;

/* The current process.  */
static process_info *current_process_;

/* The current thread.  This is either a thread of CURRENT_PROCESS, or
  NULL.  */
thread_info *current_thread;

/* The current working directory used to start the inferior.

  Empty if not specified.  */
static std::string current_inferior_cwd;

thread_info *
process_info::add_thread (ptid_t id, void *target_data)
{
 auto &new_thread = m_thread_list.emplace_back (id, this, target_data);
 bool inserted = m_ptid_thread_map.insert ({ id, &new_thread }).second;

 /* A thread with this ptid should not exist in the map yet.  */
 gdb_assert (inserted);

 if (current_thread == NULL)
   switch_to_thread (&new_thread);

 return &new_thread;
}

/* See gdbthread.h.  */

thread_info *
get_first_thread (void)
{
 return find_thread ([] (thread_info *thread)
   {
     return true;
   });
}

thread_info *
find_thread_ptid (ptid_t ptid)
{
 process_info *process = find_process_pid (ptid.pid ());
 if (process == nullptr)
   return nullptr;

 return process->find_thread (ptid);
}

/* Find a thread associated with the given PROCESS, or NULL if no
  such thread exists.  */

static thread_info *
find_thread_process (const struct process_info *const process)
{
 return find_any_thread_of_pid (process->pid);
}

/* See gdbthread.h.  */

thread_info *
find_any_thread_of_pid (int pid)
{
 return find_thread (pid, [] (thread_info *thread) {
   return true;
 });
}

void
process_info::remove_thread (thread_info *thread)
{
 if (thread->btrace != NULL)
   target_disable_btrace (thread->btrace);

 discard_queued_stop_replies (thread->id);

 if (current_thread == thread)
   switch_to_thread (nullptr);

 /* We should not try to remove a thread that was not added.  */
 gdb_assert (thread->process () == this);
 int num_erased = m_ptid_thread_map.erase (thread->id);
 gdb_assert (num_erased > 0);

 m_thread_list.erase (m_thread_list.iterator_to (*thread));
}

struct process_info *
add_process (int pid, int attached)
{
 return &all_processes.emplace_back (pid, attached);
}

/* Remove a process from the common process list and free the memory
  allocated for it.
  The caller is responsible for freeing private data first.  */

void
remove_process (struct process_info *process)
{
 clear_symbol_cache (&process->symbol_cache);
 free_all_breakpoints (process);
 gdb_assert (find_thread_process (process) == NULL);
 if (current_process () == process)
   switch_to_process (nullptr);

 all_processes.erase (all_processes.iterator_to (*process));
}

process_info *
find_process_pid (int pid)
{
 return find_process ([&] (process_info *process) {
   return process->pid == pid;
 });
}

/* Get the first process in the process list, or NULL if the list is empty.  */

process_info *
get_first_process (void)
{
 if (!all_processes.empty ())
   return &all_processes.front ();
 else
   return NULL;
}

/* Return non-zero if there are any inferiors that we have created
  (as opposed to attached-to).  */

int
have_started_inferiors_p (void)
{
 return find_process ([] (process_info *process) {
   return !process->attached;
 }) != NULL;
}

/* Return non-zero if there are any inferiors that we have attached to.  */

int
have_attached_inferiors_p (void)
{
 return find_process ([] (process_info *process) {
   return process->attached;
 }) != NULL;
}

struct process_info *
current_process (void)
{
 return current_process_;
}

/* See inferiors.h.  */

void
for_each_process (gdb::function_view<void (process_info *)> func)
{
 owning_intrusive_list<process_info>::iterator next, cur
   = all_processes.begin ();

 while (cur != all_processes.end ())
   {
     next = cur;
     next++;
     func (&*cur);
     cur = next;
   }
}

/* See inferiors.h.  */

process_info *
find_process (gdb::function_view<bool (process_info *)> func)
{
 for (process_info &process : all_processes)
   if (func (&process))
     return &process;

 return NULL;
}

/* See inferiors.h.  */

thread_info *
process_info::find_thread (ptid_t ptid)
{
 if (auto it = m_ptid_thread_map.find (ptid);
     it != m_ptid_thread_map.end ())
   return it->second;

 return nullptr;
}

/* See inferiors.h.  */

thread_info *
process_info::find_thread (gdb::function_view<bool (thread_info *)> func)
{
 for (thread_info &thread : m_thread_list)
   if (func (&thread))
     return &thread;

 return nullptr;
}

/* See gdbthread.h.  */

thread_info *
find_thread (gdb::function_view<bool (thread_info *)> func)
{
 for (process_info &process : all_processes)
   if (thread_info *thread = process.find_thread (func);
       thread != nullptr)
     return thread;

 return NULL;
}

/* See gdbthread.h.  */

thread_info *
find_thread (int pid, gdb::function_view<bool (thread_info *)> func)
{
 process_info *process = find_process_pid (pid);
 if (process == nullptr)
   return nullptr;

 return process->find_thread (func);
}

/* See gdbthread.h.  */

thread_info *
find_thread (ptid_t filter, gdb::function_view<bool (thread_info *)> func)
{
 if (filter == minus_one_ptid)
   return find_thread (func);

 process_info *process = find_process_pid (filter.pid ());
 if (process == nullptr)
   return nullptr;

 if (filter.is_pid ())
   return process->find_thread (func);

 if (thread_info *thread = process->find_thread (filter);
     thread != nullptr && func (thread))
   return thread;

 return nullptr;
}

/* See gdbthread.h.  */

void
for_each_thread (gdb::function_view<void (thread_info *)> func)
{
 for_each_process ([&] (process_info *proc)
   {
     proc->for_each_thread (func);
   });
}

/* See inferiors.h.  */

void
process_info::for_each_thread (gdb::function_view<void (thread_info *)> func)
{
 owning_intrusive_list<thread_info>::iterator next, cur
   = m_thread_list.begin ();

 while (cur != m_thread_list.end ())
   {
     /* FUNC may alter the current iterator.  */
     next = cur;
     next++;
     func (&*cur);
     cur = next;
   }
}

/* See gdbthread.h.  */

void
for_each_thread (ptid_t ptid, gdb::function_view<void (thread_info *)> func)
{
 if (ptid == minus_one_ptid)
   for_each_thread (func);
 else if (ptid.is_pid ())
   {
     process_info *process = find_process_pid (ptid.pid ());

     if (process != nullptr)
       process->for_each_thread (func);
   }
 else
   find_thread (ptid, [func] (thread_info *thread)
     {
       func (thread);
       return false;
     });
}

/* See gdbthread.h.  */

thread_info *
find_thread_in_random (ptid_t ptid,
                      gdb::function_view<bool (thread_info *)> func)
{
 int count = 0;
 int random_selector;

 /* First count how many interesting entries we have.  */
 for_each_thread (ptid, [&] (thread_info *thread)
   {
     if (func (thread))
       count++;
   });

 if (count == 0)
   return nullptr;

 /* Now randomly pick an entry out of those.  */
 random_selector = (int)
   ((count * (double) rand ()) / (RAND_MAX + 1.0));

 thread_info *thread = find_thread (ptid, [&] (thread_info *thr_arg)
   {
     return func (thr_arg) && (random_selector-- == 0);
   });

 gdb_assert (thread != NULL);

 return thread;
}

/* See gdbthread.h.  */

thread_info *
find_thread_in_random (gdb::function_view<bool (thread_info *)> func)
{
 return find_thread_in_random (minus_one_ptid, func);
}

/* See gdbsupport/common-gdbthread.h.  */

void
switch_to_thread (process_stratum_target *ops, ptid_t ptid)
{
 gdb_assert (ptid != minus_one_ptid);
 switch_to_thread (find_thread_ptid (ptid));
}

/* See gdbthread.h.  */

void
switch_to_thread (thread_info *thread)
{
 if (thread != nullptr)
   current_process_ = thread->process ();
 else
   current_process_ = nullptr;
 current_thread = thread;
}

/* See inferiors.h.  */

void
switch_to_process (process_info *proc)
{
 current_process_ = proc;
 current_thread = nullptr;
}

/* See gdbsupport/common-inferior.h.  */

const std::string &
get_inferior_cwd ()
{
 return current_inferior_cwd;
}

/* See inferiors.h.  */

void
set_inferior_cwd (std::string cwd)
{
 current_inferior_cwd = std::move (cwd);
}

scoped_restore_current_thread::scoped_restore_current_thread ()
{
 m_process = current_process_;
 m_thread = current_thread;
}

scoped_restore_current_thread::~scoped_restore_current_thread ()
{
 if (m_dont_restore)
   return;

 if (m_thread != nullptr)
   switch_to_thread (m_thread);
 else
   switch_to_process (m_process);
}