Decouple RulesCacheDelegate from RulesRegistry

chrome/browser/extensions/api/declarative/rules_registry.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_RULES_REGISTRY_H__
 #define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_RULES_REGISTRY_H__
 
 #include "chrome/browser/extensions/api/declarative/rules_registry.h"
 
 #include <map>
@@ skipping 26 matching lines @@
 // RulesRegistry::Rule objects. It contains all the methods that need to run on
 // the registry thread; methods that need to run on the UI thread are separated
 // in the RulesCacheDelegate object.
 class RulesRegistry : public base::RefCountedThreadSafe<RulesRegistry> {
  public:
   typedef extensions::api::events::Rule Rule;
 
   enum Defaults { DEFAULT_PRIORITY = 100 };
   // After the RulesCacheDelegate object (the part of the registry which runs on
   // the UI thread) is created, a pointer to it is passed to |*ui_part|.
-  // If |log_storage_init_delay| is set, the delay caused by loading and
-  // registering rules on initialization will be logged with UMA.
   // In tests, |profile| and |ui_part| can be NULL (at the same time). In that
   // case the storage functionality disabled (no RulesCacheDelegate object
-  // created) and the |log_storage_init_delay| flag is ignored.
+  // created).
   RulesRegistry(Profile* profile,
                 const std::string& event_name,
-                content::BrowserThread::ID owner_thread,
-                bool log_storage_init_delay,
-                scoped_ptr<RulesCacheDelegate>* ui_part);
+                content::BrowserThread::ID owner_thread);
 
   const OneShotEvent& ready() const {
     return ready_;
   }
 
+  base::WeakPtr<RulesRegistry> GetWeakPtr() {

[Jeffrey Yasskin, 2013/11/01 00:15:09]

It's good to avoid passing WeakPtrs out of the class when possible. Can we
organize ownership so we don't need this anymore?

Probably not in this CL.

[Fady Samuel, 2013/11/01 15:13:39]

I'll take care of this in a subsequent CL. Thanks!

+    DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
+    return weak_ptr_factory_.GetWeakPtr();
+  }
+
   // RulesRegistry implementation:
 
   // Registers |rules|, owned by |extension_id| to this RulesRegistry.
   // If a concrete RuleRegistry does not support some of the rules,
   // it may ignore them.
   //
   // |rules| is a list of Rule instances following the definition of the
   // declarative extension APIs. It is guaranteed that each rule in |rules| has
   // a unique name within the scope of |extension_id| that has not been
   // registered before, unless it has been removed again.
@@ skipping 40 matching lines @@
 
   // Same as GetRules but returns all rules owned by |extension_id|.
   std::string GetAllRules(
       const std::string& extension_id,
       std::vector<linked_ptr<RulesRegistry::Rule> >* out);
 
   // Called to notify the RulesRegistry that an extension has been unloaded
   // and all rules of this extension need to be removed.
   void OnExtensionUnloaded(const std::string& extension_id);
 
+  // Assigns a RulesCacheDelegate to this RulesRegistry. This delegate is
+  // responsible for storing the rules and retreiving them.
+  bool SetCacheDelegate(base::WeakPtr<RulesCacheDelegate> cache_delegate);

[Jeffrey Yasskin, 2013/11/01 00:15:09]

I think it's safe to pass WeakPtrs by reference, which can avoid some refcount
operations.

[Jeffrey Yasskin, 2013/11/01 00:15:09]

For functions that return bool, you need to say what the return value means.
However, I think in this case it'd be better to CHECK or DCHECK and return void,
since it's a programming error to set the cache delegate twice.

[Fady Samuel, 2013/11/01 15:13:39]

Done.

[Fady Samuel, 2013/11/01 15:13:39]

Done.

+
   // Returns the number of entries in used_rule_identifiers_ for leak detection.
   // Every ExtensionId counts as one entry, even if it contains no rules.
   size_t GetNumberOfUsedRuleIdentifiersForTesting() const;
 
+  // Returns the profile where the rules registry lives.
+  Profile* profile() const { return profile_; }
+
   // Returns the ID of the thread on which the rules registry lives.
   // It is safe to call this function from any thread.
   content::BrowserThread::ID owner_thread() const { return owner_thread_; }
 
   // The name of the event with which rules are registered.
   const std::string& event_name() const { return event_name_; }
 
  protected:
   virtual ~RulesRegistry();
 
@@ skipping 31 matching lines @@
   // Common processing after extension's rules have changed.
   void ProcessChangedRules(const std::string& extension_id);
 
   // Calls ProcessChangedRules if |process_changed_rules_requested_| ==
   // NOT_SCHEDULED_FOR_PROCESSING.
   void MaybeProcessChangedRules(const std::string& extension_id);
 
   // Process the callbacks once the registry gets ready.
   void MarkReady(base::Time storage_init_time);
 
-  // Deserialize the rules from the given Value object and add them to the
-  // RulesRegistry.
-  void DeserializeAndAddRules(const std::string& extension_id,
-                              scoped_ptr<base::Value> rules);
-
+  // The profile to which this rules registry belongs.
+  Profile* profile_;
 
   // The ID of the thread on which the rules registry lives.
   const content::BrowserThread::ID owner_thread_;
 
   // The name of the event with which rules are registered.
   const std::string event_name_;
 
   RulesDictionary rules_;
 
   // Signaled when we have finished reading from storage for all extensions that
   // are loaded on startup.
   OneShotEvent ready_;
 
   // The factory needs to be declared before |cache_delegate_|, so that it can
   // produce a pointer as a construction argument for |cache_delegate_|.
   base::WeakPtrFactory<RulesRegistry> weak_ptr_factory_;
 
   // |cache_delegate_| is owned by the registry service. If |cache_delegate_| is
   // NULL, then the storage functionality is disabled (this is used in tests).
   // This registry cannot own |cache_delegate_| because during the time after
   // rules registry service shuts down on UI thread, and the registry is
   // destroyed on its thread, the use of the |cache_delegate_| would not be
   // safe. The registry only ever associates with one RulesCacheDelegate
   // instance.
-  const base::WeakPtr<RulesCacheDelegate> cache_delegate_;
+  base::WeakPtr<RulesCacheDelegate> cache_delegate_;
 
   ProcessChangedRulesState process_changed_rules_requested_;
 
   // Returns whether any existing rule is registered with identifier |rule_id|
   // for extension |extension_id|.
   bool IsUniqueId(const std::string& extension_id,
                   const std::string& rule_id) const;
 
   // Creates an ID that is unique within the scope of|extension_id|.
   std::string GenerateUniqueId(const std::string& extension_id);
@@ skipping 21 matching lines @@
   typedef std::map<ExtensionId, std::set<RuleIdentifier> > RuleIdentifiersMap;
   RuleIdentifiersMap used_rule_identifiers_;
   int last_generated_rule_identifier_id_;
 
   DISALLOW_COPY_AND_ASSIGN(RulesRegistry);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_RULES_REGISTRY_H__