aboutsummaryrefslogtreecommitdiff
path: root/libbuild2/rule.hxx
blob: 7e5ddb17538d24cdc9f1964b1762857ad6ab5145 (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
// file      : libbuild2/rule.hxx -*- C++ -*-
// license   : MIT; see accompanying LICENSE file

#ifndef LIBBUILD2_RULE_HXX
#define LIBBUILD2_RULE_HXX

#include <libbuild2/types.hxx>
#include <libbuild2/forward.hxx>
#include <libbuild2/utility.hxx>

#include <libbuild2/action.hxx>
#include <libbuild2/target.hxx>
#include <libbuild2/recipe.hxx>

#include <libbuild2/export.hxx>

namespace build2
{
  // Rule interface (see also simple_rule below for a simplified version).
  //
  // Once a rule is registered (for a scope), it is treated as immutable. If
  // you need to modify some state (e.g., counters or some such), then make
  // sure things are MT-safe.
  //
  // Note: match() could be called multiple times (so should be idempotent)
  // and it may not be followed by apply().
  //
  // The hint argument is the rule hint, if any, that was used to select this
  // rule. While normally not factored into the match decision, a rule may
  // "try harder" if a hint was specified (see cc::link_rule for an example).
  //
  // The match_extra argument (the type is defined in target.hxx) is used to
  // pass additional information that is only needed by some rule
  // implementations. It is also a way for us to later pass more information
  // without breaking source compatibility.
  //
  // A rule may adjust post hoc prerequisites by overriding apply_posthoc().
  // See match_extra::posthoc_prerequisite_targets for background and details.
  //
  // A rule may support match options and if such a rule is rematched with
  // different options, then reapply() is called. See
  // match_extra::{cur,new}_options for background and details.
  //
  struct match_extra;

  class LIBBUILD2_SYMEXPORT rule
  {
  public:
    virtual bool
    match (action, target&, const string& hint, match_extra&) const = 0;

    virtual recipe
    apply (action, target&, match_extra&) const = 0;

    virtual void
    apply_posthoc (action, target&, match_extra&) const;

    virtual void
    reapply (action, target&, match_extra&) const;

    rule () = default;

    virtual
    ~rule ();

    rule (const rule&) = delete;
    rule& operator= (const rule&) = delete;

    // Resolve a project-qualified target in a rule-specific manner.
    //
    // This is optional functionality that may be provided by some rules to
    // facilitate immediate importation of certain target types. See the
    // import machinery for details. The default implementation always returns
    // NULL.
    //
    // Note that if this function returns a target, it should have the
    // extension assigned so that as_name() returns a stable name.
    //
    virtual const target*
    import (const prerequisite_key&,
            const optional<string>& metadata,
            const location&) const;

    // Sometimes we want to match only if another rule of ours would match
    // another operation. For example, we would want our install rule to match
    // only if our update rule also matches.
    //
    // Arranging this, however, is not a simple matter of calling the other
    // rule's match(): we also have to take into account ad hoc recipes and
    // rule hints for that operation. This helper performs all the necessary
    // checks. Note: should only be called from match() (see
    // target::find_hint() for details). Note also that ad hoc recipes are
    // checked for hint_op, not action's operation.
    //
    bool
    sub_match (const string& rule_name, operation_id hint_op,
               action, target&, match_extra&) const;
  };

  // Simplified interface for rules that don't care about the hint or extras.
  //
  class LIBBUILD2_SYMEXPORT simple_rule: public rule
  {
  public:
    virtual bool
    match (action, target&) const = 0;

    virtual recipe
    apply (action, target&) const = 0;

    virtual bool
    match (action, target&, const string&, match_extra&) const override;

    virtual recipe
    apply (action, target&, match_extra&) const override;

    // The simplified version of sub_match() above.
    //
    // Note that it calls the simplified match() directly rather than going
    // through the original.
    //
    bool
    sub_match (const string& rule_name, operation_id hint_op,
               action, target&) const;
  };

  // Fallback rule that only matches if the file exists. It will also match
  // an mtime_target provided it has a set timestamp.
  //
  // Note: this rule is "hot" because it matches every static source file and
  // so we don't use simple_rule to avoid two extra virtual calls.
  //
  class LIBBUILD2_SYMEXPORT file_rule: public rule
  {
  public:
    virtual bool
    match (action, target&, const string&, match_extra&) const override;

    virtual recipe
    apply (action, target&, match_extra&) const override;

    // While this rule expects an mtime_target-based target, sometimes it's
    // necessary to register it for something less specific (normally target)
    // in order to achieve the desired rule matching priority (see the dist
    // and config modules for an example). For such cases this rule can be
    // instructed to check the type and only match if it's mtime_target-based.
    //
    file_rule (bool match_type = false): match_type_ (match_type) {}

    static const file_rule instance; // Note: does not match the target type.
    static const build2::rule_match rule_match;

  private:
    bool match_type_;
  };

  class LIBBUILD2_SYMEXPORT alias_rule: public simple_rule
  {
  public:
    virtual bool
    match (action, target&) const override;

    virtual recipe
    apply (action, target&) const override;

    alias_rule () {}
    static const alias_rule instance;
  };

  // Note that this rule ignores the dry_run flag; see mkdir() in filesystem
  // for the rationale.
  //
  class LIBBUILD2_SYMEXPORT fsdir_rule: public simple_rule
  {
  public:
    virtual bool
    match (action, target&) const override;

    virtual recipe
    apply (action, target&) const override;

    static target_state
    perform_update (action, const target&);

    static target_state
    perform_clean (action, const target&);

    // Sometimes, as an optimization, we want to emulate execute_direct()
    // of fsdir{} without the overhead of switching to the execute phase.
    //
    static void
    perform_update_direct (action, const target&);

    static void
    perform_clean_direct (action, const target&);

    fsdir_rule () {}
    static const fsdir_rule instance;
  };

  // Fallback rule that always matches and does nothing.
  //
  class LIBBUILD2_SYMEXPORT noop_rule: public simple_rule
  {
  public:
    virtual bool
    match (action, target&) const override;

    virtual recipe
    apply (action, target&) const override;

    noop_rule () {}
    static const noop_rule instance;
  };

  // Ad hoc rule.
  //
  // Used for both ad hoc pattern rules and ad hoc recipes. For recipes, it's
  // essentially a rule of one case. Note that when used as part of a pattern,
  // the implementation cannot use the match_extra::data() facility nor the
  // target auxiliary data storage until the pattern's apply_*() calls have
  // been made.
  //
  // Note also that when used as part of a pattern, the rule is also register
  // for the dist meta-operation (unless there is an explicit recipe for dist)
  // in order to inject additional pattern prerequisites which may "pull"
  // additional sources into the distribution.
  //
  // Note: not exported.
  //
  class adhoc_rule_pattern;

  class adhoc_rule: public rule
  {
  public:
    location_value          loc;     // Buildfile location of the recipe.
    size_t                  braces;  // Number of braces in multi-brace tokens.
    small_vector<action, 1> actions; // Actions this rule is for.

    // If not NULL then this rule (recipe, really) belongs to an ad hoc
    // pattern rule and match() should call the pattern's match() and
    // apply() should call the pattern's apply_*() functions (see below).
    //
    const adhoc_rule_pattern* pattern = nullptr;

    adhoc_rule (string name, const location& l, size_t b)
      : loc (l),
        braces (b),
        rule_match (move (name), static_cast<const rule&> (*this)) {}

    // Set the rule text, handle any recipe-specific attributes, and return
    // true if the recipe builds anything in the build/recipes/ directory and
    // therefore requires cleanup.
    //
    // Scope is the scope of the recipe and target type is the type of the
    // first target (for ad hoc recipe) or primary group member type (for ad
    // hoc pattern rule). The idea is that an implementation may make certain
    // assumptions based on the first target type (e.g., file vs non-file
    // based) in which case it should also enforce (e.g., in match()) that any
    // other targets that share this recipe are also of suitable type.
    //
    // Note also that this function is called after the actions member has
    // been populated.
    //
    virtual bool
    recipe_text (const scope&, const target_type&, string&&, attributes&) = 0;

  public:
    // Some of the operations come in compensating pairs, such as update and
    // clean, install and uninstall. An ad hoc rule implementation may choose
    // to provide a fallback implementation of a reverse operation if it is
    // providing the other half.
    //
    virtual bool
    reverse_fallback (action, const target_type&) const;

    // The default implementation forwards to the pattern's match() if there
    // is a pattern and returns true otherwise.
    //
    // Note also that in case of a member of a group-based target, match() is
    // called on the group while apply() on the member (see match_rule_impl()
    // in algorithms.cxx for details). This means that match() may be called
    // without having the target locked and as a result match() should (unless
    // known to only match a non-group) treat the target as const and only
    // rely on immutable information (type, name, etc) since the group could
    // be matched concurrenly. This case can be detected by examining
    // match_extra::locked (see adhoc_rule_regex_pattern::match() for a
    // use-case).
    //
    virtual bool
    match (action, target&, const string&, match_extra&) const override;

    // Dump support.
    //
    virtual void
    dump_attributes (ostream&) const;

    virtual void
    dump_text (ostream&, string& indentation) const = 0;

    // Implementation details.
    //
  public:
    // The name in rule_match is used to match hints and in diagnostics. The
    // former does not apply to ad hoc recipes (but does apply to ad hoc
    // rules).
    //
    const build2::rule_match rule_match;

    static const dir_path recipes_build_dir;

    // Scope operation callback that cleans up ad hoc recipe builds.
    //
    static target_state
    clean_recipes_build (action, const scope&, const dir&);
  };

  // A mix-in interface for ad hoc rules that support recipes with deadlines.
  //
  class adhoc_rule_with_deadline
  {
  public:
    virtual
    ~adhoc_rule_with_deadline ();

    // Return empty recipe if one with the deadline cannot be provided for
    // this action. In this case the caller may fallback to the normal
    // apply().
    //
    virtual recipe
    apply (action, target&, match_extra&, const optional<timestamp>&) const = 0;
  };

  // Ad hoc rule pattern.
  //
  // Note: exported since may be accessed by ad hoc recipe implementation.
  //
  class LIBBUILD2_SYMEXPORT adhoc_rule_pattern
  {
  public:
    const scope&                            rule_scope;
    const string                            rule_name;
    const target_type&                      type;      // Primary target type.
    small_vector<shared_ptr<adhoc_rule>, 1> rules;     // Really a unique_ptr.

    adhoc_rule_pattern (const scope& s, string n, const target_type& t)
        : rule_scope (s),
          rule_name (move (n)),
          type (t),
          fallback_rule_ (rules) {}

    virtual
    ~adhoc_rule_pattern ();

  public:
    // Note: the adhoc_rule::match() restrictions apply here as well.
    //
    virtual bool
    match (action, const target&, const string&, match_extra&) const = 0;

    // Append additional group members. Note that this function should handle
    // both ad hoc and explicit groups.
    //
    virtual void
    apply_group_members (action, target&,
                         const scope& base,
                         match_extra&) const = 0;

    // The implementation should append pattern prerequisites to
    // t.prerequisite_targets[a] but not match. It should set bit 2 in
    // prerequisite_target::include to indicate update=match and bit 3
    // to indicate update=unmatch.
    //
    virtual void
    apply_prerequisites (action, target&,
                         const scope& base,
                         match_extra&) const = 0;

    // Dump support.
    //
    virtual void
    dump (ostream&) const = 0;

    // Gory implementation details (see match_impl()).
    //
  public:
    class fallback_rule: public rule
    {
    public:
      const small_vector<shared_ptr<adhoc_rule>, 1>& rules;

      explicit
      fallback_rule (const small_vector<shared_ptr<adhoc_rule>, 1>& rs)
          : rules (rs) {}

      // Dummy (never called).
      //
      virtual bool
      match (action, target&, const string&, match_extra&) const override;

      virtual recipe
      apply (action, target&, match_extra&) const override;
    };

    fallback_rule fallback_rule_;
  };
}

#endif // LIBBUILD2_RULE_HXX