RulesRegistry for declarative APIs.

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__
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/values.h"
+
+namespace extensions {
+
+// Interface for rule registries.
+class RulesRegistry {
+ public:
+  typedef base::Callback<void(const std::string&)> SetErrorCallback;
+
+  virtual ~RulesRegistry() {}
+
+  // 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.
+  // The ownership of rules remains with the caller.
+  // |set_error_callback| can be called to relay an error message.
+  //
+  // Returns true if the function is successful.
+  //
+  // IMPORTANT: This function is atomic. Either all rules that are deemed
+  // relevant are added or none.
+  virtual bool AddRules(const std::string& extension_id,
+                        const std::vector<DictionaryValue*>& rules,
+                        SetErrorCallback set_error_callback) = 0;

[not at google - send to devlin, 2012/02/02 11:59:16]

I don't understand why errors communicated via a callback in this way. Why not
pass a std::string*? Having it as a callback implies some kind of asynchronous
API, which wouldn't work the way this API is being used (the API handling
implementation in declarative_api.cc is synchronous).

However, even simpler, I think you can return std::string from AddRules such
that an empty return value implies success.

Ditto RemoveRules.

[battre, 2012/02/02 19:12:36]

Done.

+
+  // Unregisters all rules listed in |rule_identifiers| and owned by
+  // |extension_id| from this RulesRegistry. If |rule_identifiers| is empty, all
+  // rules of this extension will be unregistered.
+  // Some or all IDs in |rule_identifiers| may not affect this RulesRegistry.
+  // |set_error_callback| can be called to relay an error message.
+  //
+  // Returns true if the function is successful.
+  //
+  // IMPORTANT: This function is atomic. Either all rules that are deemed
+  // relevant are removed or none.
+  virtual bool RemoveRules(const std::string& extension_id,
+                           const std::vector<std::string>& rule_identifiers,
+                           SetErrorCallback set_error_callback) = 0;
+
+  // Returns all rules listed in |rule_identifiers| and owned by |extension_id|
+  // registered in this RuleRegistry. If |rule_identifiers| is empty, all rules
+  // of |extension_id| are returned.
+  // The returned rules are stored in |out|. Ownership is passed to the caller.
+  virtual void GetRules(const std::string& extension_id,
+                        const std::vector<std::string>& rule_identifiers,
+                        std::vector<DictionaryValue*>* out) = 0;
+
+  // Called to notify the RulesRegistry that an extension has been unloaded
+  // and all rules of this extension need to be removed.
+  virtual void OnExtensionUnloaded(const std::string& extension_id) = 0;
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_RULES_REGISTRY_H__