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 backtrace *m_backtrace_list;
  76 #define backtrace_list (current_thread->m_backtrace_list)
  77
  78   struct catchtag *m_catchlist;
  79 #define catchlist (current_thread->m_catchlist)
  80
  81   /* Chain of condition handlers currently in effect.
  82      The elements of this chain are contained in the stack frames
  83      of Fcondition_case and internal_condition_case.
  84      When an error is signaled (by calling Fsignal, below),
  85      this chain is searched for an element that applies.  */
  86   struct handler *m_handlerlist;
  87 #define handlerlist (current_thread->m_handlerlist)
  88
  89   /* Count levels of GCPRO to detect failure to UNGCPRO.  */
  90   int m_gcpro_level;
  91 #define gcpro_level (current_thread->m_gcpro_level)
  92
  93   /* Current number of specbindings allocated in specpdl.  */
  94   ptrdiff_t m_specpdl_size;
  95 #define specpdl_size (current_thread->m_specpdl_size)
  96
  97   /* Pointer to beginning of specpdl.  */
  98   struct specbinding *m_specpdl;
  99 #define specpdl (current_thread->m_specpdl)
 100
 101   /* Pointer to first unused element in specpdl.  */
 102   struct specbinding *m_specpdl_ptr;
 103 #define specpdl_ptr (current_thread->m_specpdl_ptr)
 104
 105   /* Pointer to the first "saved" element in specpdl.  When this
 106      thread is swapped out, the current values of all specpdl bindings
 107      are pushed onto the specpdl; then these are popped again when
 108      switching back to this thread.  */
 109   struct specbinding *m_saved_specpdl_ptr;
 110
 111   /* Depth in Lisp evaluations and function calls.  */
 112   EMACS_INT m_lisp_eval_depth;
 113 #define lisp_eval_depth (current_thread->m_lisp_eval_depth)
 114
 115   /* This points to the current buffer.  */
 116   struct buffer *m_current_buffer;
 117 #define current_buffer (current_thread->m_current_buffer)
 118
 119   /* Every call to re_match, etc., must pass &search_regs as the regs
 120      argument unless you can show it is unnecessary (i.e., if re_match
 121      is certainly going to be called again before region-around-match
 122      can be called).
 123
 124      Since the registers are now dynamically allocated, we need to make
 125      sure not to refer to the Nth register before checking that it has
 126      been allocated by checking search_regs.num_regs.
 127
 128      The regex code keeps track of whether it has allocated the search
 129      buffer using bits in the re_pattern_buffer.  This means that whenever
 130      you compile a new pattern, it completely forgets whether it has
 131      allocated any registers, and will allocate new registers the next
 132      time you call a searching or matching function.  Therefore, we need
 133      to call re_set_registers after compiling a new pattern or after
 134      setting the match registers, so that the regex functions will be
 135      able to free or re-allocate it properly.  */
 136   struct re_registers m_search_regs;
 137 #define search_regs (current_thread->m_search_regs)
 138
 139   /* If non-zero the match data have been saved in saved_search_regs
 140      during the execution of a sentinel or filter. */
 141   bool m_search_regs_saved;
 142 #define search_regs_saved (current_thread->m_search_regs_saved)
 143
 144   struct re_registers m_saved_search_regs;
 145 #define saved_search_regs (current_thread->m_saved_search_regs)
 146
 147   /* This is the string or buffer in which we
 148      are matching.  It is used for looking up syntax properties.  */
 149   Lisp_Object m_re_match_object;
 150 #define re_match_object (current_thread->m_re_match_object)
 151
 152   /* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
 153      also be assigned to arbitrarily: each pattern buffer stores its own
 154      syntax, so it can be changed between regex compilations.  */
 155   reg_syntax_t m_re_syntax_options;
 156 #define re_syntax_options (current_thread->m_re_syntax_options)
 157
 158   /* Regexp to use to replace spaces, or NULL meaning don't.  */
 159   /*re_char*/ unsigned char *m_whitespace_regexp;
 160 #define whitespace_regexp (current_thread->m_whitespace_regexp)
 161
 162   /* This variable is different from waiting_for_input in keyboard.c.
 163      It is used to communicate to a lisp process-filter/sentinel (via the
 164      function Fwaiting_for_user_input_p) whether Emacs was waiting
 165      for user-input when that process-filter was called.
 166      waiting_for_input cannot be used as that is by definition 0 when
 167      lisp code is being evalled.
 168      This is also used in record_asynch_buffer_change.
 169      For that purpose, this must be 0
 170      when not inside wait_reading_process_output.  */
 171   int m_waiting_for_user_input_p;
 172 #define waiting_for_user_input_p (current_thread->m_waiting_for_user_input_p)
 173
 174   /* The OS identifier for this thread.  */
 175   sys_thread_t thread_id;
 176
 177   /* The condition variable for this thread.  This is associated with
 178      the global lock.  This thread broadcasts to it when it exits.  */
 179   sys_cond_t thread_condvar;
 180
 181   /* This thread might be waiting for some condition.  If so, this
 182      points to the condition.  If the thread is interrupted, the
 183      interrupter should broadcast to this condition.  */
 184   sys_cond_t *wait_condvar;
 185
 186   /* Threads are kept on a linked list.  */
 187   struct thread_state *next_thread;
 188 };
 189
 190 /* A mutex in lisp is represented by a system condition variable.
 191    The system mutex associated with this condition variable is the
 192    global lock.
 193
 194    Using a condition variable lets us implement interruptibility for
 195    lisp mutexes.  */
 196 typedef struct
 197 {
 198   /* The owning thread, or NULL if unlocked.  */
 199   struct thread_state *owner;
 200   /* The lock count.  */
 201   unsigned int count;
 202   /* The underlying system condition variable.  */
 203   sys_cond_t condition;
 204 } lisp_mutex_t;
 205
 206 /* A mutex as a lisp object.  */
 207 struct Lisp_Mutex
 208 {
 209   struct vectorlike_header header;
 210
 211   /* The name of the mutex, or nil.  */
 212   Lisp_Object name;
 213
 214   /* The lower-level mutex object.  */
 215   lisp_mutex_t mutex;
 216 };
 217
 218 /* A condition variable as a lisp object.  */
 219 struct Lisp_CondVar
 220 {
 221   struct vectorlike_header header;
 222
 223   /* The associated mutex.  */
 224   Lisp_Object mutex;
 225
 226   /* The name of the condition variable, or nil.  */
 227   Lisp_Object name;
 228
 229   /* The lower-level condition variable object.  */
 230   sys_cond_t cond;
 231 };
 232
 233 extern struct thread_state *current_thread;
 234
 235 extern void unmark_threads (void);
 236 extern void finalize_one_thread (struct thread_state *state);
 237 extern void finalize_one_mutex (struct Lisp_Mutex *);
 238 extern void finalize_one_condvar (struct Lisp_CondVar *);
 239
 240 extern void init_threads_once (void);
 241 extern void init_threads (void);
 242 extern void syms_of_threads (void);
 243
 244 typedef int select_func (int, SELECT_TYPE *, SELECT_TYPE *, SELECT_TYPE *,
 245                          EMACS_TIME *, sigset_t *);
 246
 247 int thread_select  (select_func *func, int max_fds, SELECT_TYPE *rfds,
 248                     SELECT_TYPE *wfds, SELECT_TYPE *efds, EMACS_TIME *timeout,
 249                     sigset_t *sigmask);
 250
 251 #endif /* THREAD_H */