Create a mechanism define declarative rules via the extension manifest.

extensions/browser/api/declarative/rules_registry.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/api/declarative/rules_registry.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "extensions/browser/api/declarative/rules_cache_delegate.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/state_store.h"
 #include "extensions/common/extension.h"
+#include "extensions/common/manifest_constants.h"
+
+namespace extensions {
 
 namespace {
 
 const char kSuccess[] = "";
 const char kDuplicateRuleId[] = "Duplicate rule ID: %s";
+const char kErrorCannotRemoveManifestRules[] =
+    "Rules declared in the 'event_rules' manifest field cannot be removed";
 
 scoped_ptr<base::Value> RulesToValue(
-    const std::vector<linked_ptr<extensions::RulesRegistry::Rule> >& rules) {
+    const std::vector<linked_ptr<RulesRegistry::Rule>>& rules) {
   scoped_ptr<base::ListValue> list(new base::ListValue());
   for (size_t i = 0; i < rules.size(); ++i)
     list->Append(rules[i]->ToValue().release());
   return list.Pass();
 }
 
-std::vector<linked_ptr<extensions::RulesRegistry::Rule> > RulesFromValue(
+std::vector<linked_ptr<RulesRegistry::Rule>> RulesFromValue(
     const base::Value* value) {
-  std::vector<linked_ptr<extensions::RulesRegistry::Rule> > rules;
+  std::vector<linked_ptr<RulesRegistry::Rule>> rules;
 
   const base::ListValue* list = NULL;
   if (!value || !value->GetAsList(&list))
     return rules;
 
   rules.reserve(list->GetSize());
   for (size_t i = 0; i < list->GetSize(); ++i) {
     const base::DictionaryValue* dict = NULL;
     if (!list->GetDictionary(i, &dict))
       continue;
-    linked_ptr<extensions::RulesRegistry::Rule> rule(
-        new extensions::RulesRegistry::Rule());
-    if (extensions::RulesRegistry::Rule::Populate(*dict, rule.get()))
+    linked_ptr<RulesRegistry::Rule> rule(new RulesRegistry::Rule());
+    if (RulesRegistry::Rule::Populate(*dict, rule.get()))
       rules.push_back(rule);
   }
 
   return rules;
 }
 
+// Converts a rule defined in the manifest into a JSON internal format. The
+// difference is that actions and conditions use a "type" key to define the
+// type of rule/condition, while the internal format uses a "instanceType" key
+// for this. This function walks through all the conditions and rules to swap
+// the manifest key for the internal key.
+bool ConvertManifestRule(const linked_ptr<RulesRegistry::Rule>& rule) {
+  auto convert_list = [](std::vector<linked_ptr<base::Value>>& list) {
+    for (const linked_ptr<base::Value>& value : list) {
+      base::DictionaryValue* dictionary = nullptr;
+      if (!value->GetAsDictionary(&dictionary))
+        return false;
+      std::string type;
+      if (!dictionary->GetString("type", &type))
+        return false;
+      dictionary->Remove("type", nullptr);
+      dictionary->SetString("instanceType", type);
+    }
+    return true;
+  };
+  return convert_list(rule->actions) && convert_list(rule->conditions);
+}
+
+std::vector<linked_ptr<RulesRegistry::Rule>> RulesFromManifest(
+    const base::Value* value,
+    const std::string& event_name) {
+  std::vector<linked_ptr<RulesRegistry::Rule>> rules;
+
+  //  The following is an example of how an event programmatic rule definition

[Mike Wittman, 2015/06/05 23:15:58]

You'll need to add something like this to the manifest API documentation in
chrome/common/extensions/docs as well.

+  //  translates to a manifest definition.
+  //
+  //  From javascript:
+  //
+  //  chrome.declarativeContent.onPageChanged.addRules([{
+  //    actions: [
+  //      new chrome.declarativeContent.ShowPageAction()
+  //    ],
+  //    conditions: [
+  //      new chrome.declarativeContent.PageStateMatcher({css: ["video"]})
+  //    ]
+  //  }]);
+  //
+  //  In manifest:
+  //
+  //  "event_rules": [{
+  //    "event" : "declarativeContent.onPageChanged",
+  //    "actions" : [{
+  //      "type": "declarativeContent.ShowPageAction"
+  //    }],
+  //    "conditions" : [{
+  //      "css": ["video"],
+  //      "type" : "declarativeContent.PageStateMatcher"
+  //    }]
+  //  }]
+  //
+  //  The javascript objects get translated into JSON objects with a "type"
+  //  field to indicate the instance type. Instead of adding rules to a
+  //  specific event list, each rule has an "event" field to indicate which
+  //  event it applies to.
+  //
+  const base::ListValue* list = nullptr;
+  if (!value->GetAsList(&list))
+    return rules;
+
+  for (size_t i = 0; i < list->GetSize(); ++i) {
+    const base::DictionaryValue* dict = nullptr;
+    if (!list->GetDictionary(i, &dict))
+      continue;
+    std::string event;
+    if (!dict->GetString("event", &event) || event_name != event) {
+      continue;
+    }
+    linked_ptr<RulesRegistry::Rule> rule(new RulesRegistry::Rule());
+    if (RulesRegistry::Rule::Populate(*dict, rule.get()) &&
+        ConvertManifestRule(rule)) {
+      rules.push_back(rule);
+    }
+  }
+
+  return rules;
+}
+
 std::string ToId(int identifier) {
   return base::StringPrintf("_%d_", identifier);
 }
 
 }  // namespace
 
 
-namespace extensions {
-
 // RulesRegistry
 
 RulesRegistry::RulesRegistry(content::BrowserContext* browser_context,
                              const std::string& event_name,
                              content::BrowserThread::ID owner_thread,
                              RulesCacheDelegate* cache_delegate,
                              int id)
     : browser_context_(browser_context),
       owner_thread_(owner_thread),
       event_name_(event_name),
       id_(id),
       ready_(/*signaled=*/!cache_delegate),  // Immediately ready if no cache
                                              // delegate to wait for.
       last_generated_rule_identifier_id_(0),
       weak_ptr_factory_(browser_context_ ? this : NULL) {
   if (cache_delegate) {
     cache_delegate_ = cache_delegate->GetWeakPtr();
     cache_delegate->Init(this);
   }
 }
 
 std::string RulesRegistry::AddRulesNoFill(
     const std::string& extension_id,
-    const std::vector<linked_ptr<Rule> >& rules) {
+    const std::vector<linked_ptr<Rule>>& rules,
+    RulesDictionary& out) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
   // Verify that all rule IDs are new.
   for (std::vector<linked_ptr<Rule> >::const_iterator i =
       rules.begin(); i != rules.end(); ++i) {
     const RuleId& rule_id = *((*i)->id);
     // Every rule should have a priority assigned.
     DCHECK((*i)->priority);
     RulesDictionaryKey key(extension_id, rule_id);
-    if (rules_.find(key) != rules_.end())
+    if (rules_.find(key) != rules_.end() ||
+        manifest_rules_.find(key) != manifest_rules_.end())
       return base::StringPrintf(kDuplicateRuleId, rule_id.c_str());
   }
 
   std::string error = AddRulesImpl(extension_id, rules);
 
   if (!error.empty())
     return error;
 
   // Commit all rules into |rules_| on success.
   for (std::vector<linked_ptr<Rule> >::const_iterator i =
       rules.begin(); i != rules.end(); ++i) {
     const RuleId& rule_id = *((*i)->id);
     RulesDictionaryKey key(extension_id, rule_id);
-    rules_[key] = *i;
+    out[key] = *i;
   }
 
   MaybeProcessChangedRules(extension_id);
   return kSuccess;
 }
 
 std::string RulesRegistry::AddRules(
     const std::string& extension_id,
-    const std::vector<linked_ptr<Rule> >& rules) {
+    const std::vector<linked_ptr<Rule>>& rules) {
+  return AddRulesInternal(extension_id, rules, rules_);
+}
+
+std::string RulesRegistry::AddRulesInternal(
+    const std::string& extension_id,
+    const std::vector<linked_ptr<Rule>>& rules,
+    RulesDictionary& out) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
   std::string error = CheckAndFillInOptionalRules(extension_id, rules);
   if (!error.empty())
     return error;
   FillInOptionalPriorities(rules);
 
-  return AddRulesNoFill(extension_id, rules);
+  return AddRulesNoFill(extension_id, rules, out);
 }
 
 std::string RulesRegistry::RemoveRules(
     const std::string& extension_id,
     const std::vector<std::string>& rule_identifiers) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
+  // Check if any of the rules are non-removable.
+  for (RuleId rule_id : rule_identifiers) {
+    RulesDictionaryKey lookup_key(extension_id, rule_id);
+    RulesDictionary::iterator itr = manifest_rules_.find(lookup_key);
+    if (itr != manifest_rules_.end())
+      return kErrorCannotRemoveManifestRules;
+  }
+
   std::string error = RemoveRulesImpl(extension_id, rule_identifiers);
 
   if (!error.empty())
     return error;
 
   for (std::vector<std::string>::const_iterator i = rule_identifiers.begin();
        i != rule_identifiers.end();
        ++i) {
     RulesDictionaryKey lookup_key(extension_id, *i);
     rules_.erase(lookup_key);
   }
 
   MaybeProcessChangedRules(extension_id);
   RemoveUsedRuleIdentifiers(extension_id, rule_identifiers);
   return kSuccess;
 }
 
 std::string RulesRegistry::RemoveAllRules(const std::string& extension_id) {
-  std::string result = RulesRegistry::RemoveAllRulesNoStoreUpdate(extension_id);
+  std::string result =
+      RulesRegistry::RemoveAllRulesNoStoreUpdate(extension_id, false);
   MaybeProcessChangedRules(extension_id);  // Now update the prefs and store.
   return result;
 }
 
 std::string RulesRegistry::RemoveAllRulesNoStoreUpdate(
-    const std::string& extension_id) {
+    const std::string& extension_id,
+    bool uninstall) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
   std::string error = RemoveAllRulesImpl(extension_id);
 
   if (!error.empty())
     return error;
 
-  for (RulesDictionary::const_iterator i = rules_.begin();
-      i != rules_.end();) {
-    const RulesDictionaryKey& key = i->first;
-    ++i;
-    if (key.first == extension_id)
-      rules_.erase(key);
-  }
+  auto remove_rules = [&extension_id](RulesDictionary& dictionary) {
+    for (auto it = dictionary.begin(); it != dictionary.end();) {
+      if (it->first.first == extension_id)
+        dictionary.erase(it++);
+      else
+        ++it;
+    }
+  };
+  remove_rules(rules_);
+  if (uninstall)
+    remove_rules(manifest_rules_);
 
   RemoveAllUsedRuleIdentifiers(extension_id);
   return kSuccess;
 }
 
 void RulesRegistry::GetRules(const std::string& extension_id,
                              const std::vector<std::string>& rule_identifiers,
                              std::vector<linked_ptr<Rule> >* out) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
-  for (std::vector<std::string>::const_iterator i = rule_identifiers.begin();
-      i != rule_identifiers.end(); ++i) {
-    RulesDictionaryKey lookup_key(extension_id, *i);
+  for (const auto& i : rule_identifiers) {
+    RulesDictionaryKey lookup_key(extension_id, i);
     RulesDictionary::iterator entry = rules_.find(lookup_key);
+    if (entry == rules_.end())
+      entry = manifest_rules_.find(lookup_key);
     if (entry != rules_.end())
       out->push_back(entry->second);
   }
 }
 
+void RulesRegistry::GetRules(
+    const std::string& extension_id,
+    RulesDictionary& rules,
+    std::vector<linked_ptr<RulesRegistry::Rule>>* out) {
+  for (const auto& i : rules) {
+    const RulesDictionaryKey& key = i.first;
+    if (key.first == extension_id)
+      out->push_back(i.second);
+  }
+}
+
 void RulesRegistry::GetAllRules(const std::string& extension_id,
                                 std::vector<linked_ptr<Rule> >* out) {
   DCHECK_CURRENTLY_ON(owner_thread());
-  for (RulesDictionary::const_iterator i = rules_.begin();
-      i != rules_.end(); ++i) {
-    const RulesDictionaryKey& key = i->first;
-    if (key.first == extension_id)
-      out->push_back(i->second);
-  }
+  GetRules(extension_id, manifest_rules_, out);
+  GetRules(extension_id, rules_, out);
 }
 
-void RulesRegistry::OnExtensionUnloaded(const std::string& extension_id) {
+void RulesRegistry::OnExtensionUnloaded(const Extension* extension) {
   DCHECK_CURRENTLY_ON(owner_thread());
-  std::string error = RemoveAllRulesImpl(extension_id);
+  std::string error = RemoveAllRulesImpl(extension->id());
   if (!error.empty())
     LOG(ERROR) << error;
 }
 
-void RulesRegistry::OnExtensionUninstalled(const std::string& extension_id) {
+void RulesRegistry::OnExtensionUninstalled(const Extension* extension) {
   DCHECK_CURRENTLY_ON(owner_thread());
-  std::string error = RemoveAllRulesNoStoreUpdate(extension_id);
+  std::string error = RemoveAllRulesNoStoreUpdate(extension->id(), true);
   if (!error.empty())
     LOG(ERROR) << error;
 }
 
-void RulesRegistry::OnExtensionLoaded(const std::string& extension_id) {
+void RulesRegistry::OnExtensionLoaded(const Extension* extension) {
   DCHECK_CURRENTLY_ON(owner_thread());
-  std::vector<linked_ptr<Rule> > rules;
-  GetAllRules(extension_id, &rules);
-  std::string error = AddRulesImpl(extension_id, rules);
+  std::vector<linked_ptr<Rule>> rules;
+  GetAllRules(extension->id(), &rules);
+  const base::ListValue* value = NULL;
+  if (extension->manifest()->GetList(manifest_keys::kEventRules, &value)) {
+    std::string error =
+        AddRulesInternal(extension->id(), RulesFromManifest(value, event_name_),
+                         manifest_rules_);
+    if (!error.empty())
+      LOG(ERROR) << error;
+  }
+  std::string error = AddRulesImpl(extension->id(), rules);
   if (!error.empty())
     LOG(ERROR) << error;
 }
 
 size_t RulesRegistry::GetNumberOfUsedRuleIdentifiersForTesting() const {
   size_t entry_count = 0u;
   for (RuleIdentifiersMap::const_iterator extension =
            used_rule_identifiers_.begin();
        extension != used_rule_identifiers_.end();
        ++extension) {
     // Each extension is counted as 1 just for being there. Otherwise we miss
     // keys with empty values.
     entry_count += 1u + extension->second.size();
   }
   return entry_count;
 }
 
 void RulesRegistry::DeserializeAndAddRules(
     const std::string& extension_id,
     scoped_ptr<base::Value> rules) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
-  AddRulesNoFill(extension_id, RulesFromValue(rules.get()));
+  AddRulesNoFill(extension_id, RulesFromValue(rules.get()), rules_);
 }
 
 RulesRegistry::~RulesRegistry() {
 }
 
 void RulesRegistry::MarkReady(base::Time storage_init_time) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
   if (!storage_init_time.is_null()) {
     UMA_HISTOGRAM_TIMES("Extensions.DeclarativeRulesStorageInitialization",
                         base::Time::Now() - storage_init_time);
   }
 
   ready_.Signal();
 }
 
 void RulesRegistry::ProcessChangedRules(const std::string& extension_id) {
   DCHECK_CURRENTLY_ON(owner_thread());
 
   DCHECK(ContainsKey(process_changed_rules_requested_, extension_id));
   process_changed_rules_requested_[extension_id] = NOT_SCHEDULED_FOR_PROCESSING;
 
   std::vector<linked_ptr<Rule> > new_rules;
-  GetAllRules(extension_id, &new_rules);
+  GetRules(extension_id, rules_, &new_rules);
   content::BrowserThread::PostTask(
-      content::BrowserThread::UI,
-      FROM_HERE,
-      base::Bind(&RulesCacheDelegate::WriteToStorage,
-                 cache_delegate_,
-                 extension_id,
-                 base::Passed(RulesToValue(new_rules))));
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&RulesCacheDelegate::WriteToStorage, cache_delegate_,
+                 extension_id, base::Passed(RulesToValue(new_rules))));
 }
 
 void RulesRegistry::MaybeProcessChangedRules(const std::string& extension_id) {
   // Read and initialize |process_changed_rules_requested_[extension_id]| if
   // necessary. (Note that the insertion below will not overwrite
   // |process_changed_rules_requested_[extension_id]| if that already exists.
   std::pair<ProcessStateMap::iterator, bool> insertion =
       process_changed_rules_requested_.insert(std::make_pair(
           extension_id,
           browser_context_ ? NOT_SCHEDULED_FOR_PROCESSING : NEVER_PROCESS));
@@ skipping 73 matching lines @@
   for (i = identifiers.begin(); i != identifiers.end(); ++i)
     used_rule_identifiers_[extension_id].erase(*i);
 }
 
 void RulesRegistry::RemoveAllUsedRuleIdentifiers(
     const std::string& extension_id) {
   used_rule_identifiers_.erase(extension_id);
 }
 
 }  // namespace extensions