Implement API features for the Extension API feature system

chrome/common/extensions/api/extension_api.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 "chrome/common/extensions/api/extension_api.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 216 matching lines @@
     // TODO(aa): Remove this code when all API descriptions have been updated.
     *feature_type = "api";
     *feature_name = full_name;
     return;
   }
 
   *feature_type = full_name.substr(0, colon_index);
   *feature_name = full_name.substr(colon_index + 1);
 }
 
-bool ExtensionAPI::UsesFeatureSystem(const std::string& full_name) {
-  std::string api_name = GetAPINameFromFullName(full_name, NULL);
-  return features_.find(api_name) != features_.end();
-}
-
 void ExtensionAPI::LoadSchema(const std::string& name,
                               const base::StringPiece& schema) {
   scoped_ptr<ListValue> schema_list(LoadSchemaList(name, schema));
   std::string schema_namespace;
 
   while (!schema_list->empty()) {
     DictionaryValue* schema = NULL;
     {
       Value* value = NULL;
       schema_list->Remove(schema_list->GetSize() - 1, &value);
@@ skipping 73 matching lines @@
         child_feature->set_name(schema_namespace + "." + child_name);
         CHECK(schema_features->insert(
             std::make_pair(child_name,
                            make_linked_ptr(child_feature.release()))).second);
       }
     }
   }
 }
 
 ExtensionAPI::ExtensionAPI() {
-  RegisterDependencyProvider("api", this);
-
-  // TODO(aa): Can remove this when all JSON files are converted.
-  RegisterDependencyProvider("", this);
 }
 
 ExtensionAPI::~ExtensionAPI() {
 }
 
 void ExtensionAPI::InitDefaultConfiguration() {
   RegisterDependencyProvider(
+      "api", BaseFeatureProvider::GetApiFeatures());
+  RegisterDependencyProvider(
       "manifest", BaseFeatureProvider::GetManifestFeatures());
   RegisterDependencyProvider(
       "permission", BaseFeatureProvider::GetPermissionFeatures());
 
   // Schemas to be loaded from resources.
   CHECK(unloaded_schemas_.empty());
   RegisterSchema("app", ReadFromResource(
       IDR_EXTENSION_API_JSON_APP));
   RegisterSchema("browserAction", ReadFromResource(
       IDR_EXTENSION_API_JSON_BROWSERACTION));
@@ skipping 59 matching lines @@
 
 void ExtensionAPI::RegisterDependencyProvider(const std::string& name,
                                               FeatureProvider* provider) {
   dependency_providers_[name] = provider;
 }
 
 Feature::Availability ExtensionAPI::IsAvailable(const std::string& full_name,
                                                 const Extension* extension,
                                                 Feature::Context context,
                                                 const GURL& url) {
-  std::set<std::string> dependency_names;
-  dependency_names.insert(full_name);
-  ResolveDependencies(&dependency_names);
+  std::string feature_type;
+  std::string feature_name;
+  SplitDependencyName(full_name, &feature_type, &feature_name);
+
+  std::string child_name;
+  std::string api_name = GetAPINameFromFullName(feature_name, &child_name);
+
+  Feature* feature = GetFeatureDependency(full_name);
 
   // Check APIs not using the feature system first.
-  if (!UsesFeatureSystem(full_name)) {
-    return IsNonFeatureAPIAvailable(full_name, context, extension, url) ?
+  if (!feature) {
+    return IsNonFeatureAPIAvailable(api_name, context, extension, url) ?
         Feature::CreateAvailability(Feature::IS_AVAILABLE, "") :
         Feature::CreateAvailability(Feature::INVALID_CONTEXT,
                                     kUnavailableMessage);
   }
 
-  for (std::set<std::string>::iterator iter = dependency_names.begin();
-       iter != dependency_names.end(); ++iter) {
-    Feature* feature = GetFeatureDependency(*iter);
-    CHECK(feature) << *iter;
+  Feature::Availability availability =
+      feature->IsAvailableToContext(extension, context, url);
+  if (!availability.is_available())
+    return availability;
 
-    Feature::Availability availability =
-        feature->IsAvailableToContext(extension, context, url);
-    if (!availability.is_available())
-      return availability;
+  for (std::set<std::string>::iterator iter = feature->dependencies().begin();
+       iter != feature->dependencies().end(); ++iter) {
+    Feature::Availability dependency_availability =
+        IsAvailable(*iter, extension, context, url);
+    if (!dependency_availability.is_available())
+      return dependency_availability;
   }
 
   return Feature::CreateAvailability(Feature::IS_AVAILABLE, "");
 }
 
 bool ExtensionAPI::IsPrivileged(const std::string& full_name) {
   std::string child_name;
   std::string api_name = GetAPINameFromFullName(full_name, &child_name);
+  Feature* feature = GetFeatureDependency(full_name);
 
   // First try to use the feature system.
-  Feature* feature(GetFeature(full_name));
   if (feature) {
-    // An API is 'privileged' if it or any of its dependencies can only be run
-    // in a blessed context.
-    std::set<std::string> resolved_dependencies;
-    resolved_dependencies.insert(full_name);
-    ResolveDependencies(&resolved_dependencies);
-    for (std::set<std::string>::iterator iter = resolved_dependencies.begin();
-         iter != resolved_dependencies.end(); ++iter) {
-      Feature* dependency = GetFeatureDependency(*iter);
-      for (std::set<Feature::Context>::iterator context =
-               dependency->GetContexts()->begin();
-           context != dependency->GetContexts()->end(); ++context) {
-        if (*context != Feature::BLESSED_EXTENSION_CONTEXT)
-          return false;
-      }
-    }
-    return true;
+    // An API is 'privileged' if it can only be run in a blessed context.
+    return feature->GetContexts()->size() ==
+        feature->GetContexts()->count(Feature::BLESSED_EXTENSION_CONTEXT);
   }
 
+  // Get the schema now to populate |completely_unprivileged_apis_|.
+  const DictionaryValue* schema = GetSchema(api_name);
   // If this API hasn't been converted yet, fall back to the old system.
   if (completely_unprivileged_apis_.count(api_name))
     return false;
 
-  const DictionaryValue* schema = GetSchema(api_name);
   if (partially_unprivileged_apis_.count(api_name))
     return IsChildNamePrivileged(schema, child_name);
 
   return true;
 }
 
 bool ExtensionAPI::IsChildNamePrivileged(const DictionaryValue* name_space_node,
                                          const std::string& child_name) {
   bool unprivileged = false;
   const DictionaryValue* child = GetSchemaChild(name_space_node, child_name);
@@ skipping 51 matching lines @@
 
   return true;
 }
 
 }  // namespace
 
 bool ExtensionAPI::IsNonFeatureAPIAvailable(const std::string& name,
                                             Feature::Context context,
                                             const Extension* extension,
                                             const GURL& url) {
+  // Make sure schema is loaded.
+  GetSchema(name);
   switch (context) {
     case Feature::UNSPECIFIED_CONTEXT:
       break;
 
     case Feature::BLESSED_EXTENSION_CONTEXT:
       if (extension) {
         // Availability is determined by the permissions of the extension.
         if (!IsAPIAllowed(name, extension))
           return false;
         if (!IsFeatureAllowedForExtension(name, *extension))
@@ skipping 28 matching lines @@
   std::set<std::string> result;
   for (SchemaMap::iterator i = schemas_.begin(); i != schemas_.end(); ++i)
     result.insert(i->first);
   for (UnloadedSchemaMap::iterator i = unloaded_schemas_.begin();
        i != unloaded_schemas_.end(); ++i) {
     result.insert(i->first);
   }
   return result;
 }
 
-Feature* ExtensionAPI::GetFeature(const std::string& full_name) {
-  // Ensure it's loaded.
-  GetSchema(full_name);
-
-  std::string child_name;
-  std::string api_namespace = GetAPINameFromFullName(full_name, &child_name);
-
-  APIFeatureMap::iterator feature_map = features_.find(api_namespace);
-  if (feature_map == features_.end())
-    return NULL;
-
-  Feature* result = NULL;
-  FeatureMap::iterator child_feature = feature_map->second->find(child_name);
-  if (child_feature != feature_map->second->end()) {
-    result = child_feature->second.get();
-  } else {
-    FeatureMap::iterator parent_feature = feature_map->second->find("");
-    CHECK(parent_feature != feature_map->second->end());
-    result = parent_feature->second.get();
-  }
-
-  if (result->GetContexts()->empty()) {
-    LOG(ERROR) << "API feature '" << full_name
-               << "' must specify at least one context.";
-    return NULL;
-  }
-
-  return result;
-}
-
 Feature* ExtensionAPI::GetFeatureDependency(const std::string& full_name) {
   std::string feature_type;
   std::string feature_name;
   SplitDependencyName(full_name, &feature_type, &feature_name);
 
   FeatureProviderMap::iterator provider =
       dependency_providers_.find(feature_type);
-  CHECK(provider != dependency_providers_.end()) << full_name;
+  if (provider == dependency_providers_.end())
+    return NULL;
 
   Feature* feature = provider->second->GetFeature(feature_name);
-  CHECK(feature) << full_name;
-
+  // Try getting the feature for the parent API, if this was a child.
+  if (!feature) {
+    std::string child_name;
+    feature = provider->second->GetFeature(
+        GetAPINameFromFullName(feature_name, &child_name));
+  }
   return feature;
 }
 
 std::string ExtensionAPI::GetAPINameFromFullName(const std::string& full_name,
                                                  std::string* child_name) {
   std::string api_name_candidate = full_name;
   while (true) {
     if (features_.find(api_name_candidate) != features_.end() ||
         schemas_.find(api_name_candidate) != schemas_.end() ||
         unloaded_schemas_.find(api_name_candidate) != unloaded_schemas_.end()) {
@@ skipping 19 matching lines @@
   *child_name = "";
   return "";
 }
 
 bool ExtensionAPI::IsAPIAllowed(const std::string& name,
                                 const Extension* extension) {
   return extension->required_permission_set()->HasAnyAccessToAPI(name) ||
       extension->optional_permission_set()->HasAnyAccessToAPI(name);
 }
 
-void ExtensionAPI::ResolveDependencies(std::set<std::string>* out) {
-  std::set<std::string> missing_dependencies;
-  for (std::set<std::string>::iterator i = out->begin(); i != out->end(); ++i)
-    GetMissingDependencies(*i, *out, &missing_dependencies);
-
-  while (missing_dependencies.size()) {
-    std::string next = *missing_dependencies.begin();
-    missing_dependencies.erase(next);
-    out->insert(next);
-    GetMissingDependencies(next, *out, &missing_dependencies);
-  }
-}
-
-void ExtensionAPI::GetMissingDependencies(
-    const std::string& api_name,
-    const std::set<std::string>& excluding,
-    std::set<std::string>* out) {
-  std::string feature_type;
-  std::string feature_name;
-  SplitDependencyName(api_name, &feature_type, &feature_name);
-
-  // Only API features can have dependencies for now.
-  if (feature_type != "api")
-    return;
-
-  const DictionaryValue* schema = GetSchema(feature_name);
-  CHECK(schema) << "Schema for " << feature_name << " not found";
-
-  const ListValue* dependencies = NULL;
-  if (!schema->GetList("dependencies", &dependencies))
-    return;
-
-  for (size_t i = 0; i < dependencies->GetSize(); ++i) {
-    std::string dependency_name;
-    if (dependencies->GetString(i, &dependency_name) &&
-        !excluding.count(dependency_name)) {
-      out->insert(dependency_name);
-    }
-  }
-}
-
 bool ExtensionAPI::IsPrivilegedAPI(const std::string& name) {
   return completely_unprivileged_apis_.count(name) ||
       partially_unprivileged_apis_.count(name);
 }
 
 }  // namespace extensions