src/thread.h

   1 /* Thread definitions
   2    Copyright (C) 2012, 2013 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 "regex.h"
  23
  24 #include "sysselect.h"          /* FIXME */
  25 #include "systime.h"            /* FIXME */
  26
  27 struct thread_state
  28 {
  29   struct vectorlike_header header;
  30
  31   /* The buffer in which the last search was performed, or
  32      Qt if the last search was done in a string;
  33      Qnil if no searching has been done yet.  */
  34   Lisp_Object m_last_thing_searched;
  35 #define last_thing_searched (current_thread->m_last_thing_searched)
  36
  37   Lisp_Object m_saved_last_thing_searched;
  38 #define saved_last_thing_searched (current_thread->m_saved_last_thing_searched)
  39
  40   /* The thread's name.  */
  41   Lisp_Object name;
  42
  43   /* The thread's function.  */
  44   Lisp_Object function;
  45
  46   /* If non-nil, this thread has been signalled.  */
  47   Lisp_Object error_symbol;
  48   Lisp_Object error_data;
  49
  50   /* If we are waiting for some event, this holds the object we are
  51      waiting on.  */
  52   Lisp_Object event_object;
  53
  54   /* m_gcprolist must be the first non-lisp field.  */
  55   /* Recording what needs to be marked for gc.  */
  56   struct gcpro *m_gcprolist;
  57 #define gcprolist (current_thread->m_gcprolist)
  58
  59   /* A list of currently active byte-code execution value stacks.
  60      Fbyte_code adds an entry to the head of this list before it starts
  61      processing byte-code, and it removed the entry again when it is
  62      done.  Signalling an error truncates the list analoguous to
  63      gcprolist.  */
  64   struct byte_stack *m_byte_stack_list;
  65 #define byte_stack_list (current_thread->m_byte_stack_list)
  66
  67   /* An address near the bottom of the stack.
  68      Tells GC how to save a copy of the stack.  */
  69   char *m_stack_bottom;
  70 #define stack_bottom (current_thread->m_stack_bottom)
  71
  72   /* An address near the top of the stack.  */
  73   char *stack_top;
  74
  75   struct catchtag *m_catchlist;
  76 #define catchlist (current_thread->m_catchlist)
  77
  78   /* Chain of condition handlers currently in effect.
  79      The elements of this chain are contained in the stack frames
  80      of Fcondition_case and internal_condition_case.
  81      When an error is signaled (by calling Fsignal, below),
  82      this chain is searched for an element that applies.  */
  83   struct handler *m_handlerlist;
  84 #define handlerlist (current_thread->m_handlerlist)
  85
  86   /* Count levels of GCPRO to detect failure to UNGCPRO.  */
  87   int m_gcpro_level;
  88 #define gcpro_level (current_thread->m_gcpro_level)
  89
  90   /* Current number of specbindings allocated in specpdl.  */
  91   ptrdiff_t m_specpdl_size;
  92 #define specpdl_size (current_thread->m_specpdl_size)
  93
  94   /* Pointer to beginning of specpdl.  */
  95   union specbinding *m_specpdl;
  96 #define specpdl (current_thread->m_specpdl)
  97
  98   /* Pointer to first unused element in specpdl.  */
  99   union specbinding *m_specpdl_ptr;
 100 #define specpdl_ptr (current_thread->m_specpdl_ptr)
 101
 102   /* Depth in Lisp evaluations and function calls.  */
 103   EMACS_INT m_lisp_eval_depth;
 104 #define lisp_eval_depth (current_thread->m_lisp_eval_depth)
 105
 106   /* This points to the current buffer.  */
 107   struct buffer *m_current_buffer;
 108 #define current_buffer (current_thread->m_current_buffer)
 109
 110   /* Every call to re_match, etc., must pass &search_regs as the regs
 111      argument unless you can show it is unnecessary (i.e., if re_match
 112      is certainly going to be called again before region-around-match
 113      can be called).
 114
 115      Since the registers are now dynamically allocated, we need to make
 116      sure not to refer to the Nth register before checking that it has
 117      been allocated by checking search_regs.num_regs.
 118
 119      The regex code keeps track of whether it has allocated the search
 120      buffer using bits in the re_pattern_buffer.  This means that whenever
 121      you compile a new pattern, it completely forgets whether it has
 122      allocated any registers, and will allocate new registers the next
 123      time you call a searching or matching function.  Therefore, we need
 124      to call re_set_registers after compiling a new pattern or after
 125      setting the match registers, so that the regex functions will be
 126      able to free or re-allocate it properly.  */
 127   struct re_registers m_search_regs;
 128 #define search_regs (current_thread->m_search_regs)
 129
 130   /* If non-zero the match data have been saved in saved_search_regs
 131      during the execution of a sentinel or filter. */
 132   bool m_search_regs_saved;
 133 #define search_regs_saved (current_thread->m_search_regs_saved)
 134
 135   struct re_registers m_saved_search_regs;
 136 #define saved_search_regs (current_thread->m_saved_search_regs)
 137
 138   /* This is the string or buffer in which we
 139      are matching.  It is used for looking up syntax properties.  */
 140   Lisp_Object m_re_match_object;
 141 #define re_match_object (current_thread->m_re_match_object)
 142
 143   /* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
 144      also be assigned to arbitrarily: each pattern buffer stores its own
 145      syntax, so it can be changed between regex compilations.  */
 146   reg_syntax_t m_re_syntax_options;
 147 #define re_syntax_options (current_thread->m_re_syntax_options)
 148
 149   /* Regexp to use to replace spaces, or NULL meaning don't.  */
 150   /*re_char*/ unsigned char *m_whitespace_regexp;
 151 #define whitespace_regexp (current_thread->m_whitespace_regexp)
 152
 153   /* This variable is different from waiting_for_input in keyboard.c.
 154      It is used to communicate to a lisp process-filter/sentinel (via the
 155      function Fwaiting_for_user_input_p) whether Emacs was waiting
 156      for user-input when that process-filter was called.
 157      waiting_for_input cannot be used as that is by definition 0 when
 158      lisp code is being evalled.
 159      This is also used in record_asynch_buffer_change.
 160      For that purpose, this must be 0
 161      when not inside wait_reading_process_output.  */
 162   int m_waiting_for_user_input_p;
 163 #define waiting_for_user_input_p (current_thread->m_waiting_for_user_input_p)
 164
 165   /* The OS identifier for this thread.  */
 166   sys_thread_t thread_id;
 167
 168   /* The condition variable for this thread.  This is associated with
 169      the global lock.  This thread broadcasts to it when it exits.  */
 170   sys_cond_t thread_condvar;
 171
 172   /* This thread might be waiting for some condition.  If so, this
 173      points to the condition.  If the thread is interrupted, the
 174      interrupter should broadcast to this condition.  */
 175   sys_cond_t *wait_condvar;
 176
 177   /* Threads are kept on a linked list.  */
 178   struct thread_state *next_thread;
 179 };
 180
 181 /* A mutex in lisp is represented by a system condition variable.
 182    The system mutex associated with this condition variable is the
 183    global lock.
 184
 185    Using a condition variable lets us implement interruptibility for
 186    lisp mutexes.  */
 187 typedef struct
 188 {
 189   /* The owning thread, or NULL if unlocked.  */
 190   struct thread_state *owner;
 191   /* The lock count.  */
 192   unsigned int count;
 193   /* The underlying system condition variable.  */
 194   sys_cond_t condition;
 195 } lisp_mutex_t;
 196
 197 /* A mutex as a lisp object.  */
 198 struct Lisp_Mutex
 199 {
 200   struct vectorlike_header header;
 201
 202   /* The name of the mutex, or nil.  */
 203   Lisp_Object name;
 204
 205   /* The lower-level mutex object.  */
 206   lisp_mutex_t mutex;
 207 };
 208
 209 /* A condition variable as a lisp object.  */
 210 struct Lisp_CondVar
 211 {
 212   struct vectorlike_header header;
 213
 214   /* The associated mutex.  */
 215   Lisp_Object mutex;
 216
 217   /* The name of the condition variable, or nil.  */
 218   Lisp_Object name;
 219
 220   /* The lower-level condition variable object.  */
 221   sys_cond_t cond;
 222 };
 223
 224 extern struct thread_state *current_thread;
 225
 226 extern void unmark_threads (void);
 227 extern void finalize_one_thread (struct thread_state *state);
 228 extern void finalize_one_mutex (struct Lisp_Mutex *);
 229 extern void finalize_one_condvar (struct Lisp_CondVar *);
 230
 231 extern void init_threads_once (void);
 232 extern void init_threads (void);
 233 extern void syms_of_threads (void);
 234
 235 typedef int select_func (int, SELECT_TYPE *, SELECT_TYPE *, SELECT_TYPE *,
 236                          EMACS_TIME *, sigset_t *);
 237
 238 int thread_select  (select_func *func, int max_fds, SELECT_TYPE *rfds,
 239                     SELECT_TYPE *wfds, SELECT_TYPE *efds, EMACS_TIME *timeout,
 240                     sigset_t *sigmask);
 241
 242 int thread_check_current_buffer (struct buffer *);
 243
 244 #endif /* THREAD_H */