Implement FeatureProvider for ExtensionAPI.

chrome/common/extensions/api/extension_api.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_COMMON_EXTENSIONS_API_EXTENSION_API_H_
 #define CHROME_COMMON_EXTENSIONS_API_EXTENSION_API_H_
 #pragma once
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/string_piece.h"
 #include "base/values.h"
 #include "chrome/common/extensions/feature.h"
+#include "chrome/common/extensions/feature_provider.h"
 #include "chrome/common/extensions/url_pattern_set.h"
 
 namespace base {
 class DictionaryValue;
 class ListValue;
 class Value;
 }
 
 class GURL;
 class Extension;
 class ExtensionPermissionSet;
 
 namespace extensions {
 
+class Feature;
+
 // C++ Wrapper for the JSON API definitions in chrome/common/extensions/api/.
-class ExtensionAPI {
+//
+// WARNING: This class is accessed on multiple threads in the browser process
+// (see ExtensionFunctionDispatcher). No state should be modified after
+// construction.
+class ExtensionAPI : public FeatureProvider {
  public:
-  // Returns the single instance of this class.
-  static ExtensionAPI* GetInstance();
+  // Returns a single shared instance of this class. This is the typical use
+  // case in Chrome.
+  //
+  // TODO(aa): Make this const to enforce thread-safe usage.
+  static ExtensionAPI* GetSharedInstance();
 
-  // Public for construction from unit tests. Use GetInstance() normally.
+  // Creates a new instance configured the way ExtensionAPI typically is in
+  // Chrome. Use the default constructor to get a clean instance.
+  static ExtensionAPI* CreateWithDefaultConfiguration();
+
+  // Splits a name like "permission:bookmark" into ("permission", "bookmark").
+  // The first part refers to a type of feature, for example "manifest",
+  // "permission", or "api". The second part is the full name of the feature.
+  static void SplitDependencyName(const std::string& full_name,
+                                  std::string* feature_type,
+                                  std::string* feature_name);
+
+  // Creates a completely clean instance. Configure using RegisterSchema() and
+  // RegisterDependencyProvider before use.
   ExtensionAPI();
-  ~ExtensionAPI();
+  virtual ~ExtensionAPI();
+
+  void RegisterSchema(const std::string& api_name,
+                      const base::StringPiece& source);
+
+  void RegisterDependencyProvider(const std::string& name,
+                                  FeatureProvider* provider);
+
+  // Returns true if the specified API is available. |api_full_name| can be
+  // either a namespace name (like "bookmarks") or a member name (like
+  // "bookmarks.create"). Returns true if the feature and all of its
+  // dependencies are available to the specified context.
+  bool IsAvailable(const std::string& api_full_name,
+                   const Extension* extension,
+                   Feature::Context context);
 
   // Returns true if |name| is a privileged API path. Privileged paths can only
   // be called from extension code which is running in its own designated
   // extension process. They cannot be called from extension code running in
   // content scripts, or other low-privileged contexts.
   bool IsPrivileged(const std::string& name);
 
-  // Gets the schema for the extension API with namespace |api_name|.
+  // Gets the schema for the extension API with namespace |full_name|.
   // Ownership remains with this object.
-  const base::DictionaryValue* GetSchema(const std::string& api_name);
+  const base::DictionaryValue* GetSchema(const std::string& full_name);
 
   // Gets the APIs available to |context| given an |extension| and |url|. The
   // extension or URL may not be relevant to all contexts, and may be left
   // NULL/empty.
   scoped_ptr<std::set<std::string> > GetAPIsForContext(
       Feature::Context context, const Extension* extension, const GURL& url);
 
+  // Gets a Feature object describing the API with the specified |full_name|.
+  // This can be either an API namespace (like history, or
+  // experimental.bookmarks), or it can be an individual function or event.
+  virtual scoped_ptr<Feature> GetFeature(const std::string& full_name) OVERRIDE;
+
+  // Splits a full name from the extension API into its API and child name
+  // parts. Some examples:
+  //
+  // "bookmarks.create" -> ("bookmarks", "create")
+  // "experimental.input.ui.cursorUp" -> ("experimental.input.ui", "cursorUp")
+  // "storage.sync.set" -> ("storage", "sync.get")
+  // "<unknown-api>.monkey" -> ("", "")
+  //
+  // The |child_name| parameter can be be NULL if you don't need that part.
+  std::string GetAPINameFromFullName(const std::string& full_name,
+                                     std::string* child_name);
+
+  void InitDefaultConfiguration();
+
+  // Loads the schemas registered with RegisterSchema().
+  void LoadAllSchemas();
+
  private:
   friend struct DefaultSingletonTraits<ExtensionAPI>;
 
   // Loads a schema.
   void LoadSchema(const base::StringPiece& schema);
 
-  // Find an item in |list| with the specified property name and value, or NULL
-  // if no such item exists.
-  base::DictionaryValue* FindListItem(const base::ListValue* list,
-                                      const std::string& property_name,
-                                      const std::string& property_value);
-
   // Returns true if the function or event under |namespace_node| with
   // the specified |child_name| is privileged, or false otherwise. If the name
   // is not found, defaults to privileged.
   bool IsChildNamePrivileged(const base::DictionaryValue* namespace_node,
-                             const std::string& child_kind,
                              const std::string& child_name);
 
   // Adds all APIs to |out| that |extension| has any permission (required or
   // optional) to use.
+  // NOTE: This only works for non-feature-controlled APIs.
+  // TODO(aa): Remove this when all APIs are converted to the feature system.
   void GetAllowedAPIs(const Extension* extension, std::set<std::string>* out);
 
+  // Gets a feature from any dependency provider.
+  scoped_ptr<Feature> GetFeatureDependency(const std::string& dependency_name);
+
   // Adds dependent schemas to |out| as determined by the "dependencies"
   // property.
+  // TODO(aa): Consider making public and adding tests.
   void ResolveDependencies(std::set<std::string>* out);
 
   // Adds any APIs listed in "dependencies" found in the schema for |api_name|
   // but not in |excluding| to |out|.
   void GetMissingDependencies(
       const std::string& api_name,
       const std::set<std::string>& excluding,
       std::set<std::string>* out);
 
   // Removes all APIs from |apis| which are *entirely* privileged. This won't
   // include APIs such as "storage" which is entirely unprivileged, nor
   // "extension" which has unprivileged components.
   void RemovePrivilegedAPIs(std::set<std::string>* apis);
 
   // Adds an APIs that match |url| to |out|.
+  // NOTE: This only works for non-feature-controlled APIs.
+  // TODO(aa): Remove this when all APIs are converted to the feature system.
   void GetAPIsMatchingURL(const GURL& url, std::set<std::string>* out);
 
-  // Loads all remaining resources from |unloaded_schemas_|.
-  void LoadAllSchemas();
-
-  static ExtensionAPI* instance_;
-
   // Map from each API that hasn't been loaded yet to the schema which defines
   // it. Note that there may be multiple APIs per schema.
   std::map<std::string, base::StringPiece> unloaded_schemas_;
 
   // Schemas for each namespace.
   typedef std::map<std::string, linked_ptr<const DictionaryValue> > SchemaMap;
   SchemaMap schemas_;
 
   // APIs that are entirely unprivileged.
   std::set<std::string> completely_unprivileged_apis_;
 
   // APIs that are not entirely unprivileged, but have unprivileged components.
   std::set<std::string> partially_unprivileged_apis_;
 
   // APIs that have URL matching permissions.
   std::map<std::string, URLPatternSet> url_matching_apis_;
 
+  typedef std::map<std::string, linked_ptr<Feature> > FeatureMap;
+  typedef std::map<std::string, linked_ptr<FeatureMap> > APIFeatureMap;
+  APIFeatureMap features_;
+
+  // FeatureProviders used for resolving dependencies.
+  typedef std::map<std::string, FeatureProvider*> FeatureProviderMap;
+  FeatureProviderMap dependency_providers_;
+
   DISALLOW_COPY_AND_ASSIGN(ExtensionAPI);
 };
 
 }  // extensions
 
 #endif  // CHROME_COMMON_EXTENSIONS_API_EXTENSION_API_H_