aboutsummaryrefslogtreecommitdiff
path: root/libbuild2/target.ixx
blob: dd377b0441c0461e1e2fac2056780b908e5e8fe7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
// file      : libbuild2/target.ixx -*- C++ -*-
// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

#include <cstring> // memcpy()

#include <libbuild2/filesystem.hxx> // mtime()

#include <libbuild2/export.hxx>

namespace build2
{
  // target
  //
  inline const string* target::
  ext () const
  {
    slock l (ctx.targets.mutex_);
    return *ext_ ? &**ext_ : nullptr;
  }

  inline target_key target::
  key () const
  {
    const string* e (ext ());
    return target_key {
      &type (),
      &dir,
      &out,
      &name,
      e != nullptr ? optional<string> (*e) : nullopt};
  }

  inline auto target::
  prerequisites () const -> const prerequisites_type&
  {
    return prerequisites_state_.load (memory_order_acquire) == 2
      ? prerequisites_
      : empty_prerequisites_;
  }

  inline bool target::
  prerequisites (prerequisites_type&& p) const
  {
    target& x (const_cast<target&> (*this)); // MT-aware.

    uint8_t e (0);
    if (x.prerequisites_state_.compare_exchange_strong (
          e,
          1,
          memory_order_acq_rel,
          memory_order_acquire))
    {
      x.prerequisites_ = move (p);
      x.prerequisites_state_.fetch_add (1, memory_order_release);
      return true;
    }
    else
    {
      // Spin the transition out so that prerequisites() doesn't return empty.
      //
      for (; e == 1; e = prerequisites_state_.load (memory_order_acquire))
        /*this_thread::yield ()*/ ;

      return false;
    }
  }

  inline bool target::
  group_state (action a) const
  {
    // We go an extra step and short-circuit to the target state even if the
    // raw state is not group provided the recipe is group_recipe and the
    // state is unknown (see mtime() for a discussion on why we do it).
    //
    const opstate& s (state[a]);

    if (s.state == target_state::group)
      return true;

    if (s.state == target_state::unknown && group != nullptr)
    {
      if (recipe_function* const* f = s.recipe.target<recipe_function*> ())
        return *f == &group_action;
    }

    return false;
  }

  inline pair<bool, target_state> target::
  matched_state_impl (action a) const
  {
    assert (ctx.phase == run_phase::match);

    // Note that the "tried" state is "final".
    //
    const opstate& s (state[a]);

    // Note: already synchronized.
    size_t o (s.task_count.load (memory_order_relaxed) - ctx.count_base ());

    if (o == offset_tried)
      return make_pair (false, target_state::unknown);
    else
    {
      // Normally applied but can also be already executed.
      //
      assert (o == offset_applied || o == offset_executed);
      return make_pair (true, (group_state (a) ? group->state[a] : s).state);
    }
  }

  inline target_state target::
  executed_state_impl (action a) const
  {
    assert (ctx.phase == run_phase::execute);
    return (group_state (a) ? group->state : state)[a].state;
  }

  inline target_state target::
  matched_state (action a, bool fail) const
  {
    // Note that the target could be being asynchronously re-matched.
    //
    pair<bool, target_state> r (matched_state_impl (a));

    if (fail && (!r.first || r.second == target_state::failed))
      throw failed ();

    return r.second;
  }

  inline pair<bool, target_state> target::
  try_matched_state (action a, bool fail) const
  {
    pair<bool, target_state> r (matched_state_impl (a));

    if (fail && r.first && r.second == target_state::failed)
      throw failed ();

    return r;
  }

  inline target_state target::
  executed_state (action a, bool fail) const
  {
    target_state r (executed_state_impl (a));

    if (fail && r == target_state::failed)
      throw failed ();

    return r;
  }

  inline bool target::
  has_prerequisites () const
  {
    return !prerequisites ().empty ();
  }

  inline bool target::
  has_group_prerequisites () const
  {
    return has_prerequisites () ||
      (group != nullptr && !group->has_prerequisites ());
  }

  inline bool target::
  unchanged (action a) const
  {
    return matched_state_impl (a).second == target_state::unchanged;
  }

  inline ostream&
  operator<< (ostream& os, const target& t)
  {
    return os << t.key ();
  }

  // mark()/unmark()
  //

  // VC15 doesn't like if we use (abstract) target here.
  //
  static_assert (alignof (file) % 4 == 0, "unexpected target alignment");

  inline void
  mark (const target*& p, uint8_t m)
  {
    uintptr_t i (reinterpret_cast<uintptr_t> (p));
    i |= m & 0x03;
    p = reinterpret_cast<const target*> (i);
  }

  inline uint8_t
  marked (const target* p)
  {
    uintptr_t i (reinterpret_cast<uintptr_t> (p));
    return uint8_t (i & 0x03);
  }

  inline uint8_t
  unmark (const target*& p)
  {
    uintptr_t i (reinterpret_cast<uintptr_t> (p));
    uint8_t m (i & 0x03);

    if (m != 0)
    {
      i &= ~uintptr_t (0x03);
      p = reinterpret_cast<const target*> (i);
    }

    return m;
  }

  // include()
  //
  LIBBUILD2_SYMEXPORT include_type
  include_impl (action,
                const target&,
                const string&,
                const prerequisite&,
                const target*);

  inline include_type
  include (action a, const target& t, const prerequisite& p, const target* m)
  {
    // Most of the time this variable will not be specified, so let's optimize
    // for that.
    //
    if (p.vars.empty ())
      return true;

    const string* v (cast_null<string> (p.vars[t.ctx.var_include]));

    if (v == nullptr)
      return true;

    return include_impl (a, t, *v, p, m);
  }

  // group_prerequisites
  //
  inline group_prerequisites::
  group_prerequisites (const target& t)
      : t_ (t),
        g_ (t_.group == nullptr                 ||
            t_.group->member != nullptr         || // Ad hoc group member.
            t_.group->prerequisites ().empty ()
            ? nullptr : t_.group)
  {
  }

  inline group_prerequisites::
  group_prerequisites (const target& t, const target* g)
      : t_ (t),
        g_ (g == nullptr                 ||
            g->prerequisites ().empty ()
            ? nullptr : g)
  {
  }

  inline auto group_prerequisites::
  begin () const -> iterator
  {
    auto& c ((g_ != nullptr ? *g_ : t_).prerequisites ());
    return iterator (&t_, g_, &c, c.begin ());
  }

  inline auto group_prerequisites::
  end () const -> iterator
  {
    auto& c (t_.prerequisites ());
    return iterator (&t_, g_, &c, c.end ());
  }

  inline size_t group_prerequisites::
  size () const
  {
    return t_.prerequisites ().size () +
      (g_ != nullptr ? g_->prerequisites ().size () : 0);
  }

  // group_prerequisites::iterator
  //
  inline auto group_prerequisites::iterator::
  operator++ () -> iterator&
  {
    if (++i_ == c_->end () && c_ != &t_->prerequisites ())
    {
      c_ = &t_->prerequisites ();
      i_ = c_->begin ();
    }
    return *this;
  }


  inline auto group_prerequisites::iterator::
  operator-- () -> iterator&
  {
    if (i_ == c_->begin () && c_ == &t_->prerequisites ())
    {
      c_ = &g_->prerequisites ();
      i_ = c_->end ();
    }

    --i_;
    return *this;
  }

  // prerequisite_member
  //
  inline prerequisite prerequisite_member::
  as_prerequisite () const
  {
    if (member == nullptr)
      return prerequisite;

    // An ad hoc group member cannot be used as a prerequisite (use the whole
    // group instead).
    //
    assert (!member->adhoc_member ());

    return prerequisite_type (*member);
  }

  inline prerequisite_key prerequisite_member::
  key () const
  {
    return member != nullptr
      ? prerequisite_key {prerequisite.proj, member->key (), nullptr}
      : prerequisite.key ();
  }

  // prerequisite_members
  //
  LIBBUILD2_SYMEXPORT group_view
  resolve_members (action, const target&); // <libbuild2/algorithm.hxx>

  template <typename T>
  inline auto prerequisite_members_range<T>::iterator::
  operator++ () -> iterator&
  {
    if (k_ != nullptr) // Iterating over an ad hoc group.
      k_ = k_->member;

    if (k_ == nullptr && g_.count != 0) // Iterating over a normal group.
    {
      if (g_.members == nullptr || // Special case, see leave_group().
          ++j_ > g_.count)
        g_.count = 0;
    }

    if (k_ == nullptr && g_.count == 0) // Iterating over the range.
    {
      ++i_;

      if (r_->mode_ != members_mode::never &&
          i_ != r_->e_                     &&
          i_->type.see_through)
        switch_mode ();
    }

    return *this;
  }

  template <typename T>
  inline bool prerequisite_members_range<T>::iterator::
  enter_group ()
  {
    assert (k_ == nullptr); // No nested ad hoc group entering.

    // First see if we are about to enter an ad hoc group.
    //
    const target* t (g_.count != 0
                     ? j_ != 0 ? g_.members[j_ - 1] : nullptr
                     : i_->target.load (memory_order_consume));

    if (t != nullptr && t->member != nullptr)
      k_ = t; // Increment that follows will make it t->member.
    else
    {
      // Otherwise assume it is a normal group.
      //
      g_ = resolve_members (r_->a_, search (r_->t_, *i_));

      if (g_.members == nullptr) // Members are not know.
      {
        g_.count = 0;
        return false;
      }

      if (g_.count != 0) // Group is not empty.
        j_ = 0; // Account for the increment that will follow.
    }

    return true;
  }

  template <typename T>
  inline void prerequisite_members_range<T>::iterator::
  leave_group ()
  {
    if (k_ != nullptr)
    {
      // Skip until the last element (next increment will reach the end).
      //
      for (; k_->member != nullptr; k_ = k_->member) ;
    }
    else
    {
      // Pretend we are on the last member of a normal group.
      //
      j_ = 0;
      g_.count = 1;
      g_.members = nullptr; // Ugly "special case signal" for operator++.
    }
  }

  template <typename T>
  inline bool prerequisite_members_range<T>::iterator::
  group () const
  {
    return
      k_ != nullptr ? k_->member != nullptr                  : /* ad hoc   */
      g_.count != 0 ? g_.members != nullptr && j_ < g_.count : /* explicit */
      false;
  }

  inline auto
  prerequisite_members (action a, const target& t, members_mode m)
  {
    return prerequisite_members (a, t, t.prerequisites (), m);
  }

  inline auto
  reverse_prerequisite_members (action a, const target& t, members_mode m)
  {
    return prerequisite_members (a, t, reverse_iterate (t.prerequisites ()), m);
  }

  // mtime_target
  //
  inline void mtime_target::
  mtime (timestamp mt) const
  {
    mtime_.store (mt.time_since_epoch ().count (), memory_order_release);
  }

  inline timestamp mtime_target::
  load_mtime (const path& p) const
  {
    assert (ctx.phase == run_phase::execute &&
            !group_state (action () /* inner */));

    duration::rep r (mtime_.load (memory_order_consume));
    if (r == timestamp_unknown_rep)
    {
      assert (!p.empty ());

      r = build2::mtime (p).time_since_epoch ().count ();
      mtime_.store (r, memory_order_release);
    }

    return timestamp (duration (r));
  }

  inline bool mtime_target::
  newer (timestamp mt) const
  {
    assert (ctx.phase == run_phase::execute);

    timestamp mp (mtime ());

    // What do we do if timestamps are equal? This can happen, for example,
    // on filesystems that don't have subsecond resolution. There is not
    // much we can do here except detect the case where the target was
    // changed on this run.
    //
    return mt < mp || (mt == mp &&
                       executed_state_impl (action () /* inner */) ==
                       target_state::changed);
  }

  // path_target
  //
  inline const path& path_target::
  path () const
  {
    return path_state_.load (memory_order_acquire) == 2 ? path_ : empty_path;
  }

  inline const path& path_target::
  path (path_type p) const
  {
    uint8_t e (0);
    if (path_state_.compare_exchange_strong (
          e,
          1,
          memory_order_acq_rel,
          memory_order_acquire))
    {
      path_ = move (p);
      path_state_.fetch_add (1, memory_order_release);
    }
    else
    {
      // Spin the transition out.
      //
      for (; e == 1; e = path_state_.load (memory_order_acquire))
        /*this_thread::yield ()*/ ;

      assert (path_ == p);
    }

    return path_;
  }

  inline timestamp path_target::
  load_mtime () const
  {
    return mtime_target::load_mtime (path ());
  }
}