extensions/browser/api/declarative/declarative_rule.h

   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 // DeclarativeRule<>, DeclarativeConditionSet<>, and DeclarativeActionSet<>
   6 // templates usable with multiple different declarativeFoo systems.  These are
   7 // templated on the Condition and Action types that define the behavior of a
   8 // particular declarative event.
   9
  10 #ifndef EXTENSIONS_BROWSER_API_DECLARATIVE_DECLARATIVE_RULE_H__
  11 #define EXTENSIONS_BROWSER_API_DECLARATIVE_DECLARATIVE_RULE_H__
  12
  13 #include <limits>
  14 #include <set>
  15 #include <string>
  16 #include <vector>
  17
  18 #include "base/callback.h"
  19 #include "base/memory/linked_ptr.h"
  20 #include "base/memory/scoped_vector.h"
  21 #include "base/stl_util.h"
  22 #include "base/time/time.h"
  23 #include "components/url_matcher/url_matcher.h"
  24 #include "extensions/common/api/events.h"
  25 #include "extensions/common/extension.h"
  26
  27 namespace base {
  28 class Time;
  29 class Value;
  30 }
  31
  32 namespace content {
  33 class BrowserContext;
  34 }
  35
  36 namespace extensions {
  37
  38 // This class stores a set of conditions that may be part of a DeclarativeRule.
  39 // If any condition is fulfilled, the Actions of the DeclarativeRule can be
  40 // triggered.
  41 //
  42 // ConditionT should be immutable after creation.  It must define the following
  43 // members:
  44 //
  45 //   // Arguments passed through from DeclarativeConditionSet::Create.
  46 //   static scoped_ptr<ConditionT> Create(
  47 //       const Extension* extension,
  48 //       URLMatcherConditionFactory* url_matcher_condition_factory,
  49 //       // Except this argument gets elements of the Values array.
  50 //       const base::Value& definition,
  51 //       std::string* error);
  52 //   // If the Condition needs to be filtered by some URLMatcherConditionSets,
  53 //   // append them to |condition_sets|.
  54 //   // DeclarativeConditionSet::GetURLMatcherConditionSets forwards here.
  55 //   void GetURLMatcherConditionSets(
  56 //       URLMatcherConditionSet::Vector* condition_sets);
  57 //   // |match_data| passed through from DeclarativeConditionSet::IsFulfilled.
  58 //   bool IsFulfilled(const ConditionT::MatchData& match_data);
  59 template<typename ConditionT>
  60 class DeclarativeConditionSet {
  61  public:
  62   typedef std::vector<linked_ptr<base::Value>> Values;
  63   typedef std::vector<linked_ptr<const ConditionT> > Conditions;
  64   typedef typename Conditions::const_iterator const_iterator;
  65
  66   // Factory method that creates a DeclarativeConditionSet for |extension|
  67   // according to the JSON array |conditions| passed by the extension API. Sets
  68   // |error| and returns NULL in case of an error.
  69   static scoped_ptr<DeclarativeConditionSet> Create(
  70       const Extension* extension,
  71       url_matcher::URLMatcherConditionFactory* url_matcher_condition_factory,
  72       const Values& condition_values,
  73       std::string* error);
  74
  75   const Conditions& conditions() const {
  76     return conditions_;
  77   }
  78
  79   const_iterator begin() const { return conditions_.begin(); }
  80   const_iterator end() const { return conditions_.end(); }
  81
  82   // If |url_match_trigger| is not -1, this function looks for a condition
  83   // with this URLMatcherConditionSet, and forwards to that condition's
  84   // IsFulfilled(|match_data|). If there is no such condition, then false is
  85   // returned. If |url_match_trigger| is -1, this function returns whether any
  86   // of the conditions without URL attributes is satisfied.
  87   bool IsFulfilled(url_matcher::URLMatcherConditionSet::ID url_match_trigger,
  88                    const typename ConditionT::MatchData& match_data) const;
  89
  90   // Appends the URLMatcherConditionSet from all conditions to |condition_sets|.
  91   void GetURLMatcherConditionSets(
  92       url_matcher::URLMatcherConditionSet::Vector* condition_sets) const;
  93
  94   // Returns whether there are some conditions without UrlFilter attributes.
  95   bool HasConditionsWithoutUrls() const {
  96     return !conditions_without_urls_.empty();
  97   }
  98
  99  private:
 100   typedef std::map<url_matcher::URLMatcherConditionSet::ID, const ConditionT*>
 101       URLMatcherIdToCondition;
 102
 103   DeclarativeConditionSet(
 104       const Conditions& conditions,
 105       const URLMatcherIdToCondition& match_id_to_condition,
 106       const std::vector<const ConditionT*>& conditions_without_urls);
 107
 108   const URLMatcherIdToCondition match_id_to_condition_;
 109   const Conditions conditions_;
 110   const std::vector<const ConditionT*> conditions_without_urls_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(DeclarativeConditionSet);
 113 };
 114
 115 // Immutable container for multiple actions.
 116 //
 117 // ActionT should be immutable after creation.  It must define the following
 118 // members:
 119 //
 120 //   // Arguments passed through from ActionSet::Create.
 121 //   static scoped_ptr<ActionT> Create(
 122 //       const Extension* extension,
 123 //       // Except this argument gets elements of the Values array.
 124 //       const base::Value& definition,
 125 //       std::string* error, bool* bad_message);
 126 //   void Apply(const std::string& extension_id,
 127 //              const base::Time& extension_install_time,
 128 //              // Contains action-type-specific in/out parameters.
 129 //              typename ActionT::ApplyInfo* apply_info) const;
 130 //   // Only needed if the RulesRegistry calls DeclarativeActionSet::Revert().
 131 //   void Revert(const std::string& extension_id,
 132 //               const base::Time& extension_install_time,
 133 //               // Contains action-type-specific in/out parameters.
 134 //               typename ActionT::ApplyInfo* apply_info) const;
 135 //   // Return the minimum priority of rules that can be evaluated after this
 136 //   // action runs.  A suitable default value is MIN_INT.
 137 //   int minimum_priority() const;
 138 //
 139 // TODO(battre): As DeclarativeActionSet can become the single owner of all
 140 // actions, we can optimize here by making some of them singletons (e.g. Cancel
 141 // actions).
 142 template<typename ActionT>
 143 class DeclarativeActionSet {
 144  public:
 145   typedef std::vector<linked_ptr<base::Value>> Values;
 146   typedef std::vector<scoped_refptr<const ActionT> > Actions;
 147
 148   explicit DeclarativeActionSet(const Actions& actions);
 149
 150   // Factory method that instantiates a DeclarativeActionSet for |extension|
 151   // according to |actions| which represents the array of actions received from
 152   // the extension API.
 153   static scoped_ptr<DeclarativeActionSet> Create(
 154       content::BrowserContext* browser_context,
 155       const Extension* extension,
 156       const Values& action_values,
 157       std::string* error,
 158       bool* bad_message);
 159
 160   // Rules call this method when their conditions are fulfilled.
 161   void Apply(const std::string& extension_id,
 162              const base::Time& extension_install_time,
 163              typename ActionT::ApplyInfo* apply_info) const;
 164
 165   // Rules call this method when their conditions are fulfilled, but Apply has
 166   // already been called.
 167   void Reapply(const std::string& extension_id,
 168                const base::Time& extension_install_time,
 169                typename ActionT::ApplyInfo* apply_info) const;
 170
 171   // Rules call this method when they have stateful conditions, and those
 172   // conditions stop being fulfilled.  Rules with event-based conditions (e.g. a
 173   // network request happened) will never Revert() an action.
 174   void Revert(const std::string& extension_id,
 175               const base::Time& extension_install_time,
 176               typename ActionT::ApplyInfo* apply_info) const;
 177
 178   // Returns the minimum priority of rules that may be evaluated after
 179   // this rule. Defaults to MIN_INT.
 180   int GetMinimumPriority() const;
 181
 182   const Actions& actions() const { return actions_; }
 183
 184  private:
 185   const Actions actions_;
 186
 187   DISALLOW_COPY_AND_ASSIGN(DeclarativeActionSet);
 188 };
 189
 190 // Representation of a rule of a declarative API:
 191 // https://developer.chrome.com/beta/extensions/events.html#declarative.
 192 // Generally a RulesRegistry will hold a collection of Rules for a given
 193 // declarative API and contain the logic for matching and applying them.
 194 //
 195 // See DeclarativeConditionSet and DeclarativeActionSet for the requirements on
 196 // ConditionT and ActionT.
 197 template<typename ConditionT, typename ActionT>
 198 class DeclarativeRule {
 199  public:
 200   typedef std::string ExtensionId;
 201   typedef std::string RuleId;
 202   typedef std::pair<ExtensionId, RuleId> GlobalRuleId;
 203   typedef int Priority;
 204   typedef DeclarativeConditionSet<ConditionT> ConditionSet;
 205   typedef DeclarativeActionSet<ActionT> ActionSet;
 206   typedef extensions::api::events::Rule JsonRule;
 207   typedef std::vector<std::string> Tags;
 208
 209   // Checks whether the set of |conditions| and |actions| are consistent.
 210   // Returns true in case of consistency and MUST set |error| otherwise.
 211   typedef base::Callback<bool(const ConditionSet* conditions,
 212                               const ActionSet* actions,
 213                               std::string* error)> ConsistencyChecker;
 214
 215   DeclarativeRule(const GlobalRuleId& id,
 216                   const Tags& tags,
 217                   base::Time extension_installation_time,
 218                   scoped_ptr<ConditionSet> conditions,
 219                   scoped_ptr<ActionSet> actions,
 220                   Priority priority);
 221
 222   // Creates a DeclarativeRule for |extension| given a json definition.  The
 223   // format of each condition and action's json is up to the specific ConditionT
 224   // and ActionT.  |extension| may be NULL in tests.
 225   //
 226   // Before constructing the final rule, calls check_consistency(conditions,
 227   // actions, error) and returns NULL if it fails.  Pass NULL if no consistency
 228   // check is needed.  If |error| is empty, the translation was successful and
 229   // the returned rule is internally consistent.
 230   static scoped_ptr<DeclarativeRule> Create(
 231       url_matcher::URLMatcherConditionFactory* url_matcher_condition_factory,
 232       content::BrowserContext* browser_context,
 233       const Extension* extension,
 234       base::Time extension_installation_time,
 235       linked_ptr<JsonRule> rule,
 236       ConsistencyChecker check_consistency,
 237       std::string* error);
 238
 239   const GlobalRuleId& id() const { return id_; }
 240   const Tags& tags() const { return tags_; }
 241   const std::string& extension_id() const { return id_.first; }
 242   const ConditionSet& conditions() const { return *conditions_; }
 243   const ActionSet& actions() const { return *actions_; }
 244   Priority priority() const { return priority_; }
 245
 246   // Calls actions().Apply(extension_id(), extension_installation_time_,
 247   // apply_info). This function should only be called when the conditions_ are
 248   // fulfilled (from a semantic point of view; no harm is done if this function
 249   // is called at other times for testing purposes).
 250   void Apply(typename ActionT::ApplyInfo* apply_info) const;
 251
 252   // Returns the minimum priority of rules that may be evaluated after
 253   // this rule. Defaults to MIN_INT. Only valid if the conditions of this rule
 254   // are fulfilled.
 255   Priority GetMinimumPriority() const;
 256
 257  private:
 258   GlobalRuleId id_;
 259   Tags tags_;
 260   base::Time extension_installation_time_;  // For precedences of rules.
 261   scoped_ptr<ConditionSet> conditions_;
 262   scoped_ptr<ActionSet> actions_;
 263   Priority priority_;
 264
 265   DISALLOW_COPY_AND_ASSIGN(DeclarativeRule);
 266 };
 267
 268 // Implementation details below here.
 269
 270 //
 271 // DeclarativeConditionSet
 272 //
 273
 274 template<typename ConditionT>
 275 bool DeclarativeConditionSet<ConditionT>::IsFulfilled(
 276     url_matcher::URLMatcherConditionSet::ID url_match_trigger,
 277     const typename ConditionT::MatchData& match_data) const {
 278   if (url_match_trigger == -1) {
 279     // Invalid trigger -- indication that we should only check conditions
 280     // without URL attributes.
 281     for (const ConditionT* condition : conditions_without_urls_) {
 282       if (condition->IsFulfilled(match_data))
 283         return true;
 284     }
 285     return false;
 286   }
 287
 288   typename URLMatcherIdToCondition::const_iterator triggered =
 289       match_id_to_condition_.find(url_match_trigger);
 290   return (triggered != match_id_to_condition_.end() &&
 291           triggered->second->IsFulfilled(match_data));
 292 }
 293
 294 template<typename ConditionT>
 295 void DeclarativeConditionSet<ConditionT>::GetURLMatcherConditionSets(
 296     url_matcher::URLMatcherConditionSet::Vector* condition_sets) const {
 297   for (const linked_ptr<const ConditionT>& condition : conditions_)
 298     condition->GetURLMatcherConditionSets(condition_sets);
 299 }
 300
 301 // static
 302 template <typename ConditionT>
 303 scoped_ptr<DeclarativeConditionSet<ConditionT>>
 304 DeclarativeConditionSet<ConditionT>::Create(
 305     const Extension* extension,
 306     url_matcher::URLMatcherConditionFactory* url_matcher_condition_factory,
 307     const Values& condition_values,
 308     std::string* error) {
 309   Conditions result;
 310
 311   for (const linked_ptr<base::Value>& value : condition_values) {
 312     CHECK(value.get());
 313     scoped_ptr<ConditionT> condition = ConditionT::Create(
 314         extension, url_matcher_condition_factory, *value, error);
 315     if (!error->empty())
 316       return scoped_ptr<DeclarativeConditionSet>();
 317     result.push_back(make_linked_ptr(condition.release()));
 318   }
 319
 320   URLMatcherIdToCondition match_id_to_condition;
 321   std::vector<const ConditionT*> conditions_without_urls;
 322   url_matcher::URLMatcherConditionSet::Vector condition_sets;
 323
 324   for (const linked_ptr<const ConditionT>& condition : result) {
 325     condition_sets.clear();
 326     condition->GetURLMatcherConditionSets(&condition_sets);
 327     if (condition_sets.empty()) {
 328       conditions_without_urls.push_back(condition.get());
 329     } else {
 330       for (const scoped_refptr<url_matcher::URLMatcherConditionSet>& match_set :
 331            condition_sets)
 332         match_id_to_condition[match_set->id()] = condition.get();
 333     }
 334   }
 335
 336   return make_scoped_ptr(new DeclarativeConditionSet(
 337       result, match_id_to_condition, conditions_without_urls));
 338 }
 339
 340 template<typename ConditionT>
 341 DeclarativeConditionSet<ConditionT>::DeclarativeConditionSet(
 342     const Conditions& conditions,
 343     const URLMatcherIdToCondition& match_id_to_condition,
 344     const std::vector<const ConditionT*>& conditions_without_urls)
 345     : match_id_to_condition_(match_id_to_condition),
 346       conditions_(conditions),
 347       conditions_without_urls_(conditions_without_urls) {}
 348
 349 //
 350 // DeclarativeActionSet
 351 //
 352
 353 template<typename ActionT>
 354 DeclarativeActionSet<ActionT>::DeclarativeActionSet(const Actions& actions)
 355     : actions_(actions) {}
 356
 357 // static
 358 template <typename ActionT>
 359 scoped_ptr<DeclarativeActionSet<ActionT>> DeclarativeActionSet<ActionT>::Create(
 360     content::BrowserContext* browser_context,
 361     const Extension* extension,
 362     const Values& action_values,
 363     std::string* error,
 364     bool* bad_message) {
 365   *error = "";
 366   *bad_message = false;
 367   Actions result;
 368
 369   for (const linked_ptr<base::Value>& value : action_values) {
 370     CHECK(value.get());
 371     scoped_refptr<const ActionT> action =
 372         ActionT::Create(browser_context, extension, *value, error, bad_message);
 373     if (!error->empty() || *bad_message)
 374       return scoped_ptr<DeclarativeActionSet>();
 375     result.push_back(action);
 376   }
 377
 378   return scoped_ptr<DeclarativeActionSet>(new DeclarativeActionSet(result));
 379 }
 380
 381 template<typename ActionT>
 382 void DeclarativeActionSet<ActionT>::Apply(
 383     const std::string& extension_id,
 384     const base::Time& extension_install_time,
 385     typename ActionT::ApplyInfo* apply_info) const {
 386   for (const scoped_refptr<const ActionT>& action : actions_)
 387     action->Apply(extension_id, extension_install_time, apply_info);
 388 }
 389
 390 template<typename ActionT>
 391 void DeclarativeActionSet<ActionT>::Reapply(
 392     const std::string& extension_id,
 393     const base::Time& extension_install_time,
 394     typename ActionT::ApplyInfo* apply_info) const {
 395   for (const scoped_refptr<const ActionT>& action : actions_)
 396     action->Reapply(extension_id, extension_install_time, apply_info);
 397 }
 398
 399 template<typename ActionT>
 400 void DeclarativeActionSet<ActionT>::Revert(
 401     const std::string& extension_id,
 402     const base::Time& extension_install_time,
 403     typename ActionT::ApplyInfo* apply_info) const {
 404   for (const scoped_refptr<const ActionT>& action : actions_)
 405     action->Revert(extension_id, extension_install_time, apply_info);
 406 }
 407
 408 template<typename ActionT>
 409 int DeclarativeActionSet<ActionT>::GetMinimumPriority() const {
 410   int minimum_priority = std::numeric_limits<int>::min();
 411   for (typename Actions::const_iterator i = actions_.begin();
 412        i != actions_.end(); ++i) {
 413     minimum_priority = std::max(minimum_priority, (*i)->minimum_priority());
 414   }
 415   return minimum_priority;
 416 }
 417
 418 //
 419 // DeclarativeRule
 420 //
 421
 422 template<typename ConditionT, typename ActionT>
 423 DeclarativeRule<ConditionT, ActionT>::DeclarativeRule(
 424     const GlobalRuleId& id,
 425     const Tags& tags,
 426     base::Time extension_installation_time,
 427     scoped_ptr<ConditionSet> conditions,
 428     scoped_ptr<ActionSet> actions,
 429     Priority priority)
 430     : id_(id),
 431       tags_(tags),
 432       extension_installation_time_(extension_installation_time),
 433       conditions_(conditions.release()),
 434       actions_(actions.release()),
 435       priority_(priority) {
 436   CHECK(conditions_.get());
 437   CHECK(actions_.get());
 438 }
 439
 440 // static
 441 template<typename ConditionT, typename ActionT>
 442 scoped_ptr<DeclarativeRule<ConditionT, ActionT> >
 443 DeclarativeRule<ConditionT, ActionT>::Create(
 444     url_matcher::URLMatcherConditionFactory* url_matcher_condition_factory,
 445     content::BrowserContext* browser_context,
 446     const Extension* extension,
 447     base::Time extension_installation_time,
 448     linked_ptr<JsonRule> rule,
 449     ConsistencyChecker check_consistency,
 450     std::string* error) {
 451   scoped_ptr<DeclarativeRule> error_result;
 452
 453   scoped_ptr<ConditionSet> conditions = ConditionSet::Create(
 454       extension, url_matcher_condition_factory, rule->conditions, error);
 455   if (!error->empty())
 456     return error_result.Pass();
 457   CHECK(conditions.get());
 458
 459   bool bad_message = false;
 460   scoped_ptr<ActionSet> actions =
 461       ActionSet::Create(
 462           browser_context, extension, rule->actions, error, &bad_message);
 463   if (bad_message) {
 464     // TODO(battre) Export concept of bad_message to caller, the extension
 465     // should be killed in case it is true.
 466     *error = "An action of a rule set had an invalid "
 467         "structure that should have been caught by the JSON validator.";
 468     return error_result.Pass();
 469   }
 470   if (!error->empty() || bad_message)
 471     return error_result.Pass();
 472   CHECK(actions.get());
 473
 474   if (!check_consistency.is_null() &&
 475       !check_consistency.Run(conditions.get(), actions.get(), error)) {
 476     DCHECK(!error->empty());
 477     return error_result.Pass();
 478   }
 479
 480   CHECK(rule->priority.get());
 481   int priority = *(rule->priority);
 482
 483   GlobalRuleId rule_id(extension->id(), *(rule->id));
 484   Tags tags = rule->tags ? *rule->tags : Tags();
 485   return scoped_ptr<DeclarativeRule>(
 486       new DeclarativeRule(rule_id, tags, extension_installation_time,
 487                           conditions.Pass(), actions.Pass(), priority));
 488 }
 489
 490 template<typename ConditionT, typename ActionT>
 491 void DeclarativeRule<ConditionT, ActionT>::Apply(
 492     typename ActionT::ApplyInfo* apply_info) const {
 493   return actions_->Apply(extension_id(),
 494                          extension_installation_time_,
 495                          apply_info);
 496 }
 497
 498 template<typename ConditionT, typename ActionT>
 499 int DeclarativeRule<ConditionT, ActionT>::GetMinimumPriority() const {
 500   return actions_->GetMinimumPriority();
 501 }
 502
 503 }  // namespace extensions
 504
 505 #endif  // EXTENSIONS_BROWSER_API_DECLARATIVE_DECLARATIVE_RULE_H__