src/thread.h

   1 /* Thread definitions
   2 Copyright (C) 2012-2016 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software: you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation, either version 3 of the License, or
   9 (at your option) any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef THREAD_H
  20 #define THREAD_H
  21
  22 #include <sys/types.h>          /* for ssize_t used by regex.h */
  23 #include "regex.h"
  24
  25 #ifdef WINDOWSNT
  26 #include <sys/socket.h>
  27 #endif
  28
  29 #include "sysselect.h"          /* FIXME */
  30 #include "systime.h"            /* FIXME */
  31
  32 struct thread_state
  33 {
  34   struct vectorlike_header header;
  35
  36   /* The buffer in which the last search was performed, or
  37      Qt if the last search was done in a string;
  38      Qnil if no searching has been done yet.  */
  39   Lisp_Object m_last_thing_searched;
  40 #define last_thing_searched (current_thread->m_last_thing_searched)
  41
  42   Lisp_Object m_saved_last_thing_searched;
  43 #define saved_last_thing_searched (current_thread->m_saved_last_thing_searched)
  44
  45   /* The thread's name.  */
  46   Lisp_Object name;
  47
  48   /* The thread's function.  */
  49   Lisp_Object function;
  50
  51   /* If non-nil, this thread has been signaled.  */
  52   Lisp_Object error_symbol;
  53   Lisp_Object error_data;
  54
  55   /* If we are waiting for some event, this holds the object we are
  56      waiting on.  */
  57   Lisp_Object event_object;
  58
  59   /* m_stack_bottom must be the first non-Lisp field.  */
  60   /* An address near the bottom of the stack.
  61      Tells GC how to save a copy of the stack.  */
  62   char *m_stack_bottom;
  63 #define stack_bottom (current_thread->m_stack_bottom)
  64
  65   /* An address near the top of the stack.  */
  66   char *stack_top;
  67
  68   struct catchtag *m_catchlist;
  69 #define catchlist (current_thread->m_catchlist)
  70
  71   /* Chain of condition handlers currently in effect.
  72      The elements of this chain are contained in the stack frames
  73      of Fcondition_case and internal_condition_case.
  74      When an error is signaled (by calling Fsignal),
  75      this chain is searched for an element that applies.  */
  76   struct handler *m_handlerlist;
  77 #define handlerlist (current_thread->m_handlerlist)
  78
  79   struct handler *m_handlerlist_sentinel;
  80 #define handlerlist_sentinel (current_thread->m_handlerlist_sentinel)
  81
  82   /* Current number of specbindings allocated in specpdl.  */
  83   ptrdiff_t m_specpdl_size;
  84 #define specpdl_size (current_thread->m_specpdl_size)
  85
  86   /* Pointer to beginning of specpdl.  */
  87   union specbinding *m_specpdl;
  88 #define specpdl (current_thread->m_specpdl)
  89
  90   /* Pointer to first unused element in specpdl.  */
  91   union specbinding *m_specpdl_ptr;
  92 #define specpdl_ptr (current_thread->m_specpdl_ptr)
  93
  94   /* Depth in Lisp evaluations and function calls.  */
  95   EMACS_INT m_lisp_eval_depth;
  96 #define lisp_eval_depth (current_thread->m_lisp_eval_depth)
  97
  98   /* This points to the current buffer.  */
  99   struct buffer *m_current_buffer;
 100 #define current_buffer (current_thread->m_current_buffer)
 101
 102   /* Every call to re_match, etc., must pass &search_regs as the regs
 103      argument unless you can show it is unnecessary (i.e., if re_match
 104      is certainly going to be called again before region-around-match
 105      can be called).
 106
 107      Since the registers are now dynamically allocated, we need to make
 108      sure not to refer to the Nth register before checking that it has
 109      been allocated by checking search_regs.num_regs.
 110
 111      The regex code keeps track of whether it has allocated the search
 112      buffer using bits in the re_pattern_buffer.  This means that whenever
 113      you compile a new pattern, it completely forgets whether it has
 114      allocated any registers, and will allocate new registers the next
 115      time you call a searching or matching function.  Therefore, we need
 116      to call re_set_registers after compiling a new pattern or after
 117      setting the match registers, so that the regex functions will be
 118      able to free or re-allocate it properly.  */
 119   struct re_registers m_search_regs;
 120 #define search_regs (current_thread->m_search_regs)
 121
 122   /* If non-zero the match data have been saved in saved_search_regs
 123      during the execution of a sentinel or filter. */
 124   bool m_search_regs_saved;
 125 #define search_regs_saved (current_thread->m_search_regs_saved)
 126
 127   struct re_registers m_saved_search_regs;
 128 #define saved_search_regs (current_thread->m_saved_search_regs)
 129
 130   /* This is the string or buffer in which we
 131      are matching.  It is used for looking up syntax properties.
 132
 133      If the value is a Lisp string object, we are matching text in that
 134      string; if it's nil, we are matching text in the current buffer; if
 135      it's t, we are matching text in a C string.  */
 136   Lisp_Object m_re_match_object;
 137 #define re_match_object (current_thread->m_re_match_object)
 138
 139   /* This member is different from waiting_for_input.
 140      It is used to communicate to a lisp process-filter/sentinel (via the
 141      function Fwaiting_for_user_input_p) whether Emacs was waiting
 142      for user-input when that process-filter was called.
 143      waiting_for_input cannot be used as that is by definition 0 when
 144      lisp code is being evalled.
 145      This is also used in record_asynch_buffer_change.
 146      For that purpose, this must be 0
 147      when not inside wait_reading_process_output.  */
 148   int m_waiting_for_user_input_p;
 149 #define waiting_for_user_input_p (current_thread->m_waiting_for_user_input_p)
 150
 151   /* True while doing kbd input.  */
 152   bool m_waiting_for_input;
 153 #define waiting_for_input (current_thread->m_waiting_for_input)
 154
 155   /* The OS identifier for this thread.  */
 156   sys_thread_t thread_id;
 157
 158   /* The condition variable for this thread.  This is associated with
 159      the global lock.  This thread broadcasts to it when it exits.  */
 160   sys_cond_t thread_condvar;
 161
 162   /* This thread might be waiting for some condition.  If so, this
 163      points to the condition.  If the thread is interrupted, the
 164      interrupter should broadcast to this condition.  */
 165   sys_cond_t *wait_condvar;
 166
 167   /* This thread might have released the global lock.  If so, this is
 168      non-zero.  When a thread runs outside thread_select with this
 169      flag non-zero, it means it has been interrupted by SIGINT while
 170      in thread_select, and didn't have a chance of acquiring the lock.
 171      It must do so ASAP.  */
 172   int not_holding_lock;
 173
 174   /* Threads are kept on a linked list.  */
 175   struct thread_state *next_thread;
 176 };
 177
 178 /* A mutex in lisp is represented by a system condition variable.
 179    The system mutex associated with this condition variable is the
 180    global lock.
 181
 182    Using a condition variable lets us implement interruptibility for
 183    lisp mutexes.  */
 184 typedef struct
 185 {
 186   /* The owning thread, or NULL if unlocked.  */
 187   struct thread_state *owner;
 188   /* The lock count.  */
 189   unsigned int count;
 190   /* The underlying system condition variable.  */
 191   sys_cond_t condition;
 192 } lisp_mutex_t;
 193
 194 /* A mutex as a lisp object.  */
 195 struct Lisp_Mutex
 196 {
 197   struct vectorlike_header header;
 198
 199   /* The name of the mutex, or nil.  */
 200   Lisp_Object name;
 201
 202   /* The lower-level mutex object.  */
 203   lisp_mutex_t mutex;
 204 };
 205
 206 /* A condition variable as a lisp object.  */
 207 struct Lisp_CondVar
 208 {
 209   struct vectorlike_header header;
 210
 211   /* The associated mutex.  */
 212   Lisp_Object mutex;
 213
 214   /* The name of the condition variable, or nil.  */
 215   Lisp_Object name;
 216
 217   /* The lower-level condition variable object.  */
 218   sys_cond_t cond;
 219 };
 220
 221 extern struct thread_state *current_thread;
 222
 223 extern void finalize_one_thread (struct thread_state *state);
 224 extern void finalize_one_mutex (struct Lisp_Mutex *);
 225 extern void finalize_one_condvar (struct Lisp_CondVar *);
 226 extern void maybe_reacquire_global_lock (void);
 227
 228 extern void init_threads_once (void);
 229 extern void init_threads (void);
 230 extern void syms_of_threads (void);
 231 extern bool primary_thread_p (void *);
 232
 233 typedef int select_func (int, fd_set *, fd_set *, fd_set *,
 234                          const struct timespec *, const sigset_t *);
 235
 236 int thread_select  (select_func *func, int max_fds, fd_set *rfds,
 237                     fd_set *wfds, fd_set *efds, struct timespec *timeout,
 238                     sigset_t *sigmask);
 239
 240 bool thread_check_current_buffer (struct buffer *);
 241
 242 #endif /* THREAD_H */