policy: use JSON schema to deserialize entries from Windows registry.

chrome/browser/policy/registry_dict_win.cc

 // Copyright 2013 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/browser/policy/registry_dict_win.h"
 
 #include "base/json/json_reader.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_byteorder.h"
 #include "base/values.h"
 #include "base/win/registry.h"
 #include "components/json_schema/json_schema_constants.h"
 
 namespace schema = json_schema_constants;
 
 using base::win::RegistryKeyIterator;
 using base::win::RegistryValueIterator;
 
 namespace policy {
 
 namespace {
 
-// Returns the entry with key |name| in |dictionary| (can be NULL), or NULL.
-const base::DictionaryValue* GetEntry(const base::DictionaryValue* dictionary,
-                                      const std::string& name) {
-  if (!dictionary)
-    return NULL;
-  const base::DictionaryValue* entry = NULL;
-  dictionary->GetDictionaryWithoutPathExpansion(name, &entry);
-  return entry;
-}
-
 // Returns the Value type described in |schema|, or |default_type| if not found.
-base::Value::Type GetValueTypeForSchema(const base::DictionaryValue* schema,
+base::Value::Type GetValueTypeForSchema(const PolicySchema* schema,
                                         base::Value::Type default_type) {
-  // JSON-schema types to base::Value::Type mapping.
-  static const struct {
-    // JSON schema type.
-    const char* schema_type;
-    // Correspondent value type.
-    base::Value::Type value_type;
-  } kSchemaToValueTypeMap[] = {
-    { schema::kArray,        base::Value::TYPE_LIST        },
-    { schema::kBoolean,      base::Value::TYPE_BOOLEAN     },
-    { schema::kInteger,      base::Value::TYPE_INTEGER     },
-    { schema::kNull,         base::Value::TYPE_NULL        },
-    { schema::kNumber,       base::Value::TYPE_DOUBLE      },
-    { schema::kObject,       base::Value::TYPE_DICTIONARY  },
-    { schema::kString,       base::Value::TYPE_STRING      },
-  };
-
   if (!schema)
     return default_type;
-  std::string type;
-  if (!schema->GetStringWithoutPathExpansion(schema::kType, &type))
-    return default_type;
-  for (size_t i = 0; i < arraysize(kSchemaToValueTypeMap); ++i) {
-    if (type == kSchemaToValueTypeMap[i].schema_type)
-      return kSchemaToValueTypeMap[i].value_type;
-  }
-  return default_type;
+  return schema->type();
 }
 
 // Returns the schema for property |name| given the |schema| of an object.
 // Returns the "additionalProperties" schema if no specific schema for
 // |name| is present. Returns NULL if no schema is found.
-const base::DictionaryValue* GetSchemaFor(const base::DictionaryValue* schema,
-                                          const std::string& name) {
-  const base::DictionaryValue* properties =
-      GetEntry(schema, schema::kProperties);
-  const base::DictionaryValue* sub_schema = GetEntry(properties, name);
+const PolicySchema* GetSchemaFor(const PolicySchema* schema,
+                                 const std::string& name) {
+  if (!schema)
+    return NULL;
+  const PolicySchema* sub_schema = schema->GetSchemaForProperty(name);
   if (sub_schema)
     return sub_schema;
   // "additionalProperties" can be a boolean, but that case is ignored.
-  return GetEntry(schema, schema::kAdditionalProperties);
+  return schema->GetSchemaForAdditionalProperties();
 }
 
 // Converts a value (as read from the registry) to meet |schema|, converting
 // types as necessary. Unconvertible types will show up as NULL values in the
 // result.
 scoped_ptr<base::Value> ConvertValue(const base::Value& value,
-                                     const base::DictionaryValue* schema) {
+                                     const PolicySchema* schema) {
   // Figure out the type to convert to from the schema.
   const base::Value::Type result_type(
       GetValueTypeForSchema(schema, value.GetType()));
 
   // If the type is good already, go with it.
   if (value.IsType(result_type)) {
     // Recurse for complex types if there is a schema.
     if (schema) {
       const base::DictionaryValue* dict = NULL;
       const base::ListValue* list = NULL;
       if (value.GetAsDictionary(&dict)) {
         scoped_ptr<base::DictionaryValue> result(new base::DictionaryValue());
         for (base::DictionaryValue::Iterator entry(*dict); !entry.IsAtEnd();
              entry.Advance()) {
           scoped_ptr<base::Value> converted_value(
               ConvertValue(entry.value(), GetSchemaFor(schema, entry.key())));
           result->SetWithoutPathExpansion(entry.key(),
                                           converted_value.release());
         }
         return result.Pass();
       } else if (value.GetAsList(&list)) {
         scoped_ptr<base::ListValue> result(new base::ListValue());
-        const base::DictionaryValue* item_schema =
-            GetEntry(schema, schema::kItems);
+        const PolicySchema* item_schema = schema->GetSchemaForItems();
         for (base::ListValue::const_iterator entry(list->begin());
              entry != list->end(); ++entry) {
           result->Append(ConvertValue(**entry, item_schema).release());
         }
         return result.Pass();
       }
     }
     return make_scoped_ptr(value.DeepCopy());
   }
 
@@ skipping 30 matching lines @@
                  base::StringToDouble(string_value, &double_value)) {
         return make_scoped_ptr(base::Value::CreateDoubleValue(double_value));
       }
       break;
     }
     case base::Value::TYPE_LIST: {
       // Lists are encoded as subkeys with numbered value in the registry.
       const base::DictionaryValue* dict = NULL;
       if (value.GetAsDictionary(&dict)) {
         scoped_ptr<base::ListValue> result(new base::ListValue());
-        const base::DictionaryValue* item_schema =
-            GetEntry(schema, schema::kItems);
+        const PolicySchema* item_schema = schema->GetSchemaForItems();
         for (int i = 1; ; ++i) {
           const base::Value* entry = NULL;
           if (!dict->Get(base::IntToString(i), &entry))
             break;
           result->Append(ConvertValue(*entry, item_schema).release());
         }
         return result.Pass();
       }
       // Fall through in order to accept lists encoded as JSON strings.
     }
@@ skipping 169 matching lines @@
   // Recurse for all subkeys.
   for (RegistryKeyIterator it(hive, root.c_str()); it.Valid(); ++it) {
     std::string name(UTF16ToUTF8(it.Name()));
     scoped_ptr<RegistryDict> subdict(new RegistryDict());
     subdict->ReadRegistry(hive, root + L"\\" + it.Name());
     SetKey(name, subdict.Pass());
   }
 }
 
 scoped_ptr<base::Value> RegistryDict::ConvertToJSON(
-    const base::DictionaryValue* schema) const {
+    const PolicySchema* schema) const {
   base::Value::Type type =
       GetValueTypeForSchema(schema, base::Value::TYPE_DICTIONARY);
   switch (type) {
     case base::Value::TYPE_DICTIONARY: {
       scoped_ptr<base::DictionaryValue> result(new base::DictionaryValue());
       for (RegistryDict::ValueMap::const_iterator entry(values_.begin());
            entry != values_.end(); ++entry) {
         result->SetWithoutPathExpansion(
             entry->first,
             ConvertValue(*entry->second,
                          GetSchemaFor(schema, entry->first)).release());
       }
       for (RegistryDict::KeyMap::const_iterator entry(keys_.begin());
            entry != keys_.end(); ++entry) {
         result->SetWithoutPathExpansion(
             entry->first,
             entry->second->ConvertToJSON(
                 GetSchemaFor(schema, entry->first)).release());
       }
       return result.Pass();
     }
     case base::Value::TYPE_LIST: {
       scoped_ptr<base::ListValue> result(new base::ListValue());
-      const base::DictionaryValue* item_schema =
-          GetEntry(schema, schema::kItems);
+      const PolicySchema* item_schema = schema->GetSchemaForItems();
       for (int i = 1; ; ++i) {
         const std::string name(base::IntToString(i));
         const RegistryDict* key = GetKey(name);
         if (key) {
           result->Append(key->ConvertToJSON(item_schema).release());
           continue;
         }
         const base::Value* value = GetValue(name);
         if (value) {
           result->Append(ConvertValue(*value, item_schema).release());
           continue;
         }
         break;
       }
       return result.Pass();
     }
     default:
       LOG(WARNING) << "Can't convert registry key to schema type " << type;
   }
 
   return make_scoped_ptr(base::Value::CreateNullValue());
 }
 
 }  // namespace policy