tools/gn/scope.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "tools/gn/scope.h"
   6
   7 #include "base/logging.h"
   8 #include "base/stl_util.h"
   9 #include "tools/gn/parse_tree.h"
  10 #include "tools/gn/template.h"
  11
  12 namespace {
  13
  14 // FLags set in the mode_flags_ of a scope. If a bit is set, it applies
  15 // recursively to all dependent scopes.
  16 const unsigned kProcessingBuildConfigFlag = 1;
  17 const unsigned kProcessingImportFlag = 2;
  18
  19 // Returns true if this variable name should be considered private. Private
  20 // values start with an underscore, and are not imported from "gni" files
  21 // when processing an import.
  22 bool IsPrivateVar(const base::StringPiece& name) {
  23   return name.empty() || name[0] == '_';
  24 }
  25
  26 }  // namespace
  27
  28
  29 Scope::ProgrammaticProvider::~ProgrammaticProvider() {
  30   scope_->RemoveProvider(this);
  31 }
  32
  33 Scope::Scope(const Settings* settings)
  34     : const_containing_(nullptr),
  35       mutable_containing_(nullptr),
  36       settings_(settings),
  37       mode_flags_(0),
  38       item_collector_(nullptr) {
  39 }
  40
  41 Scope::Scope(Scope* parent)
  42     : const_containing_(nullptr),
  43       mutable_containing_(parent),
  44       settings_(parent->settings()),
  45       mode_flags_(0),
  46       item_collector_(nullptr) {
  47 }
  48
  49 Scope::Scope(const Scope* parent)
  50     : const_containing_(parent),
  51       mutable_containing_(nullptr),
  52       settings_(parent->settings()),
  53       mode_flags_(0),
  54       item_collector_(nullptr) {
  55 }
  56
  57 Scope::~Scope() {
  58   STLDeleteContainerPairSecondPointers(target_defaults_.begin(),
  59                                        target_defaults_.end());
  60 }
  61
  62 const Value* Scope::GetValue(const base::StringPiece& ident,
  63                              bool counts_as_used) {
  64   // First check for programatically-provided values.
  65   for (const auto& provider : programmatic_providers_) {
  66     const Value* v = provider->GetProgrammaticValue(ident);
  67     if (v)
  68       return v;
  69   }
  70
  71   RecordMap::iterator found = values_.find(ident);
  72   if (found != values_.end()) {
  73     if (counts_as_used)
  74       found->second.used = true;
  75     return &found->second.value;
  76   }
  77
  78   // Search in the parent scope.
  79   if (const_containing_)
  80     return const_containing_->GetValue(ident);
  81   if (mutable_containing_)
  82     return mutable_containing_->GetValue(ident, counts_as_used);
  83   return nullptr;
  84 }
  85
  86 Value* Scope::GetMutableValue(const base::StringPiece& ident,
  87                               bool counts_as_used) {
  88   // Don't do programatic values, which are not mutable.
  89   RecordMap::iterator found = values_.find(ident);
  90   if (found != values_.end()) {
  91     if (counts_as_used)
  92       found->second.used = true;
  93     return &found->second.value;
  94   }
  95
  96   // Search in the parent mutable scope, but not const one.
  97   if (mutable_containing_)
  98     return mutable_containing_->GetMutableValue(ident, counts_as_used);
  99   return nullptr;
 100 }
 101
 102 Value* Scope::GetValueForcedToCurrentScope(const base::StringPiece& ident,
 103                                            const ParseNode* set_node) {
 104   RecordMap::iterator found = values_.find(ident);
 105   if (found != values_.end())
 106     return &found->second.value;  // Already have in the current scope.
 107
 108   // Search in the parent scope.
 109   if (containing()) {
 110     const Value* in_containing = containing()->GetValue(ident);
 111     if (in_containing) {
 112       // Promote to current scope.
 113       return SetValue(ident, *in_containing, set_node);
 114     }
 115   }
 116   return nullptr;
 117 }
 118
 119 const Value* Scope::GetValue(const base::StringPiece& ident) const {
 120   RecordMap::const_iterator found = values_.find(ident);
 121   if (found != values_.end())
 122     return &found->second.value;
 123   if (containing())
 124     return containing()->GetValue(ident);
 125   return nullptr;
 126 }
 127
 128 Value* Scope::SetValue(const base::StringPiece& ident,
 129                        const Value& v,
 130                        const ParseNode* set_node) {
 131   Record& r = values_[ident];  // Clears any existing value.
 132   r.value = v;
 133   r.value.set_origin(set_node);
 134   return &r.value;
 135 }
 136
 137 void Scope::RemoveIdentifier(const base::StringPiece& ident) {
 138   RecordMap::iterator found = values_.find(ident);
 139   if (found != values_.end())
 140     values_.erase(found);
 141 }
 142
 143 void Scope::RemovePrivateIdentifiers() {
 144   // Do it in two phases to avoid mutating while iterating. Our hash map is
 145   // currently backed by several different vendor-specific implementations and
 146   // I'm not sure if all of them support mutating while iterating. Since this
 147   // is not perf-critical, do the safe thing.
 148   std::vector<base::StringPiece> to_remove;
 149   for (const auto& cur : values_) {
 150     if (IsPrivateVar(cur.first))
 151       to_remove.push_back(cur.first);
 152   }
 153
 154   for (const auto& cur : to_remove)
 155     values_.erase(cur);
 156 }
 157
 158 bool Scope::AddTemplate(const std::string& name, const Template* templ) {
 159   if (GetTemplate(name))
 160     return false;
 161   templates_[name] = templ;
 162   return true;
 163 }
 164
 165 const Template* Scope::GetTemplate(const std::string& name) const {
 166   TemplateMap::const_iterator found = templates_.find(name);
 167   if (found != templates_.end())
 168     return found->second.get();
 169   if (containing())
 170     return containing()->GetTemplate(name);
 171   return nullptr;
 172 }
 173
 174 void Scope::MarkUsed(const base::StringPiece& ident) {
 175   RecordMap::iterator found = values_.find(ident);
 176   if (found == values_.end()) {
 177     NOTREACHED();
 178     return;
 179   }
 180   found->second.used = true;
 181 }
 182
 183 void Scope::MarkUnused(const base::StringPiece& ident) {
 184   RecordMap::iterator found = values_.find(ident);
 185   if (found == values_.end()) {
 186     NOTREACHED();
 187     return;
 188   }
 189   found->second.used = false;
 190 }
 191
 192 bool Scope::IsSetButUnused(const base::StringPiece& ident) const {
 193   RecordMap::const_iterator found = values_.find(ident);
 194   if (found != values_.end()) {
 195     if (!found->second.used) {
 196       return true;
 197     }
 198   }
 199   return false;
 200 }
 201
 202 bool Scope::CheckForUnusedVars(Err* err) const {
 203   for (const auto& pair : values_) {
 204     if (!pair.second.used) {
 205       std::string help = "You set the variable \"" + pair.first.as_string() +
 206           "\" here and it was unused before it went\nout of scope.";
 207
 208       const BinaryOpNode* binary = pair.second.value.origin()->AsBinaryOp();
 209       if (binary && binary->op().type() == Token::EQUAL) {
 210         // Make a nicer error message for normal var sets.
 211         *err = Err(binary->left()->GetRange(), "Assignment had no effect.",
 212                    help);
 213       } else {
 214         // This will happen for internally-generated variables.
 215         *err = Err(pair.second.value.origin(), "Assignment had no effect.",
 216                    help);
 217       }
 218       return false;
 219     }
 220   }
 221   return true;
 222 }
 223
 224 void Scope::GetCurrentScopeValues(KeyValueMap* output) const {
 225   for (const auto& pair : values_)
 226     (*output)[pair.first] = pair.second.value;
 227 }
 228
 229 bool Scope::NonRecursiveMergeTo(Scope* dest,
 230                                 const MergeOptions& options,
 231                                 const ParseNode* node_for_err,
 232                                 const char* desc_for_err,
 233                                 Err* err) const {
 234   // Values.
 235   for (const auto& pair : values_) {
 236     if (options.skip_private_vars && IsPrivateVar(pair.first))
 237       continue;  // Skip this private var.
 238
 239     const Value& new_value = pair.second.value;
 240     if (!options.clobber_existing) {
 241       const Value* existing_value = dest->GetValue(pair.first);
 242       if (existing_value && new_value != *existing_value) {
 243         // Value present in both the source and the dest.
 244         std::string desc_string(desc_for_err);
 245         *err = Err(node_for_err, "Value collision.",
 246             "This " + desc_string + " contains \"" + pair.first.as_string() +
 247             "\"");
 248         err->AppendSubErr(Err(pair.second.value, "defined here.",
 249             "Which would clobber the one in your current scope"));
 250         err->AppendSubErr(Err(*existing_value, "defined here.",
 251             "Executing " + desc_string + " should not conflict with anything "
 252             "in the current\nscope unless the values are identical."));
 253         return false;
 254       }
 255     }
 256     dest->values_[pair.first] = pair.second;
 257
 258     if (options.mark_used)
 259       dest->MarkUsed(pair.first);
 260   }
 261
 262   // Target defaults are owning pointers.
 263   for (const auto& pair : target_defaults_) {
 264     if (!options.clobber_existing) {
 265       if (dest->GetTargetDefaults(pair.first)) {
 266         // TODO(brettw) it would be nice to know the origin of a
 267         // set_target_defaults so we can give locations for the colliding target
 268         // defaults.
 269         std::string desc_string(desc_for_err);
 270         *err = Err(node_for_err, "Target defaults collision.",
 271             "This " + desc_string + " contains target defaults for\n"
 272             "\"" + pair.first + "\" which would clobber one for the\n"
 273             "same target type in your current scope. It's unfortunate that I'm "
 274             "too stupid\nto tell you the location of where the target defaults "
 275             "were set. Usually\nthis happens in the BUILDCONFIG.gn file.");
 276         return false;
 277       }
 278     }
 279
 280     // Be careful to delete any pointer we're about to clobber.
 281     Scope** dest_scope = &dest->target_defaults_[pair.first];
 282     if (*dest_scope)
 283       delete *dest_scope;
 284     *dest_scope = new Scope(settings_);
 285     pair.second->NonRecursiveMergeTo(*dest_scope, options, node_for_err,
 286                                      "<SHOULDN'T HAPPEN>", err);
 287   }
 288
 289   // Sources assignment filter.
 290   if (sources_assignment_filter_) {
 291     if (!options.clobber_existing) {
 292       if (dest->GetSourcesAssignmentFilter()) {
 293         // Sources assignment filter present in both the source and the dest.
 294         std::string desc_string(desc_for_err);
 295         *err = Err(node_for_err, "Assignment filter collision.",
 296             "The " + desc_string + " contains a sources_assignment_filter "
 297             "which\nwould clobber the one in your current scope.");
 298         return false;
 299       }
 300     }
 301     dest->sources_assignment_filter_.reset(
 302         new PatternList(*sources_assignment_filter_));
 303   }
 304
 305   // Templates.
 306   for (const auto& pair : templates_) {
 307     if (options.skip_private_vars && IsPrivateVar(pair.first))
 308       continue;  // Skip this private template.
 309
 310     if (!options.clobber_existing) {
 311       const Template* existing_template = dest->GetTemplate(pair.first);
 312       // Since templates are refcounted, we can check if it's the same one by
 313       // comparing pointers.
 314       if (existing_template && pair.second.get() != existing_template) {
 315         // Rule present in both the source and the dest, and they're not the
 316         // same one.
 317         std::string desc_string(desc_for_err);
 318         *err = Err(node_for_err, "Template collision.",
 319             "This " + desc_string + " contains a template \"" +
 320             pair.first + "\"");
 321         err->AppendSubErr(Err(pair.second->GetDefinitionRange(),
 322             "defined here.",
 323             "Which would clobber the one in your current scope"));
 324         err->AppendSubErr(Err(existing_template->GetDefinitionRange(),
 325             "defined here.",
 326             "Executing " + desc_string + " should not conflict with anything "
 327             "in the current\nscope."));
 328         return false;
 329       }
 330     }
 331
 332     // Be careful to delete any pointer we're about to clobber.
 333     dest->templates_[pair.first] = pair.second;
 334   }
 335
 336   return true;
 337 }
 338
 339 scoped_ptr<Scope> Scope::MakeClosure() const {
 340   scoped_ptr<Scope> result;
 341   if (const_containing_) {
 342     // We reached the top of the mutable scope stack. The result scope just
 343     // references the const scope (which will never change).
 344     result.reset(new Scope(const_containing_));
 345   } else if (mutable_containing_) {
 346     // There are more nested mutable scopes. Recursively go up the stack to
 347     // get the closure.
 348     result = mutable_containing_->MakeClosure();
 349   } else {
 350     // This is a standalone scope, just copy it.
 351     result.reset(new Scope(settings_));
 352   }
 353
 354   // Want to clobber since we've flattened some nested scopes, and our parent
 355   // scope may have a duplicate value set.
 356   MergeOptions options;
 357   options.clobber_existing = true;
 358
 359   // Add in our variables and we're done.
 360   Err err;
 361   NonRecursiveMergeTo(result.get(), options, nullptr, "<SHOULDN'T HAPPEN>",
 362                       &err);
 363   DCHECK(!err.has_error());
 364   return result.Pass();
 365 }
 366
 367 Scope* Scope::MakeTargetDefaults(const std::string& target_type) {
 368   if (GetTargetDefaults(target_type))
 369     return nullptr;
 370
 371   Scope** dest = &target_defaults_[target_type];
 372   if (*dest) {
 373     NOTREACHED();  // Already set.
 374     return *dest;
 375   }
 376   *dest = new Scope(settings_);
 377   return *dest;
 378 }
 379
 380 const Scope* Scope::GetTargetDefaults(const std::string& target_type) const {
 381   NamedScopeMap::const_iterator found = target_defaults_.find(target_type);
 382   if (found != target_defaults_.end())
 383     return found->second;
 384   if (containing())
 385     return containing()->GetTargetDefaults(target_type);
 386   return nullptr;
 387 }
 388
 389 const PatternList* Scope::GetSourcesAssignmentFilter() const {
 390   if (sources_assignment_filter_)
 391     return sources_assignment_filter_.get();
 392   if (containing())
 393     return containing()->GetSourcesAssignmentFilter();
 394   return nullptr;
 395 }
 396
 397 void Scope::SetProcessingBuildConfig() {
 398   DCHECK((mode_flags_ & kProcessingBuildConfigFlag) == 0);
 399   mode_flags_ |= kProcessingBuildConfigFlag;
 400 }
 401
 402 void Scope::ClearProcessingBuildConfig() {
 403   DCHECK(mode_flags_ & kProcessingBuildConfigFlag);
 404   mode_flags_ &= ~(kProcessingBuildConfigFlag);
 405 }
 406
 407 bool Scope::IsProcessingBuildConfig() const {
 408   if (mode_flags_ & kProcessingBuildConfigFlag)
 409     return true;
 410   if (containing())
 411     return containing()->IsProcessingBuildConfig();
 412   return false;
 413 }
 414
 415 void Scope::SetProcessingImport() {
 416   DCHECK((mode_flags_ & kProcessingImportFlag) == 0);
 417   mode_flags_ |= kProcessingImportFlag;
 418 }
 419
 420 void Scope::ClearProcessingImport() {
 421   DCHECK(mode_flags_ & kProcessingImportFlag);
 422   mode_flags_ &= ~(kProcessingImportFlag);
 423 }
 424
 425 bool Scope::IsProcessingImport() const {
 426   if (mode_flags_ & kProcessingImportFlag)
 427     return true;
 428   if (containing())
 429     return containing()->IsProcessingImport();
 430   return false;
 431 }
 432
 433 const SourceDir& Scope::GetSourceDir() const {
 434   if (!source_dir_.is_null())
 435     return source_dir_;
 436   if (containing())
 437     return containing()->GetSourceDir();
 438   return source_dir_;
 439 }
 440
 441 Scope::ItemVector* Scope::GetItemCollector() {
 442   if (item_collector_)
 443     return item_collector_;
 444   if (mutable_containing())
 445     return mutable_containing()->GetItemCollector();
 446   return nullptr;
 447 }
 448
 449 void Scope::SetProperty(const void* key, void* value) {
 450   if (!value) {
 451     DCHECK(properties_.find(key) != properties_.end());
 452     properties_.erase(key);
 453   } else {
 454     properties_[key] = value;
 455   }
 456 }
 457
 458 void* Scope::GetProperty(const void* key, const Scope** found_on_scope) const {
 459   PropertyMap::const_iterator found = properties_.find(key);
 460   if (found != properties_.end()) {
 461     if (found_on_scope)
 462       *found_on_scope = this;
 463     return found->second;
 464   }
 465   if (containing())
 466     return containing()->GetProperty(key, found_on_scope);
 467   return nullptr;
 468 }
 469
 470 void Scope::AddProvider(ProgrammaticProvider* p) {
 471   programmatic_providers_.insert(p);
 472 }
 473
 474 void Scope::RemoveProvider(ProgrammaticProvider* p) {
 475   DCHECK(programmatic_providers_.find(p) != programmatic_providers_.end());
 476   programmatic_providers_.erase(p);
 477 }