Add dbus::PopDataAsValue

BUG=chromium-os:16557
TEST=dbus_unittests --gtest_filter="ValuesUtilTest.*"


Review URL: http://codereview.chromium.org/9702094

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@127287 0039d316-1c4b-4281-b951-d872f2087c98

dbus/dbus.gyp

@@ -32,6 +32,8 @@
         'property.cc',
         'property.h',
         'scoped_dbus_error.h',
+        'values_util.cc',
+        'values_util.h',
       ],
     },
     {
@@ -88,6 +90,7 @@
         'property_unittest.cc',
         'test_service.cc',
         'test_service.h',
+        'values_util_unittest.cc',
       ],
       'include_dirs': [
         '..',

dbus/values_util.cc

@@ -0,0 +1,185 @@
+// 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 "dbus/values_util.h"
+
+#include "base/json/json_writer.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+#include "dbus/message.h"
+
+namespace dbus {
+
+namespace {
+
+// Returns whether |value| is exactly representable by double or not.
+template<typename T>
+bool IsExactlyRepresentableByDouble(T value) {
+  return value == static_cast<T>(static_cast<double>(value));
+}
+
+// Pops values from |reader| and appends them to |list_value|.
+bool PopListElements(MessageReader* reader, ListValue* list_value) {
+  while (reader->HasMoreData()) {
+    Value* element_value = PopDataAsValue(reader);
+    if (!element_value)
+      return false;
+    list_value->Append(element_value);
+  }
+  return true;
+}
+
+// Pops dict-entries from |reader| and sets them to |dictionary_value|
+bool PopDictionaryEntries(MessageReader* reader,
+                          DictionaryValue* dictionary_value) {
+  while (reader->HasMoreData()) {
+    DCHECK_EQ(Message::DICT_ENTRY, reader->GetDataType());
+    MessageReader entry_reader(NULL);
+    if (!reader->PopDictEntry(&entry_reader))
+      return false;
+    // Get key as a string.
+    std::string key_string;
+    if (entry_reader.GetDataType() == Message::STRING) {
+      // If the type of keys is STRING, pop it directly.
+      if (!entry_reader.PopString(&key_string))
+        return false;
+    } else {
+      // If the type of keys is not STRING, convert it to string.
+      scoped_ptr<Value> key(PopDataAsValue(&entry_reader));
+      if (!key.get())
+        return false;
+      // Use JSONWriter to convert an arbitrary value to a string.
+      base::JSONWriter::Write(key.get(), &key_string);
+    }
+    // Get the value and set the key-value pair.
+    Value* value = PopDataAsValue(&entry_reader);
+    if (!value)
+      return false;
+    dictionary_value->Set(key_string, value);
+  }
+  return true;
+}
+
+}  // namespace
+
+Value* PopDataAsValue(MessageReader* reader) {
+  Value* result = NULL;
+  switch (reader->GetDataType()) {
+    case Message::INVALID_DATA:
+      // Do nothing.
+      break;
+    case Message::BYTE: {
+      uint8 value = 0;
+      if (reader->PopByte(&value))
+        result = Value::CreateIntegerValue(value);
+      break;
+    }
+    case Message::BOOL: {
+      bool value = false;
+      if (reader->PopBool(&value))
+        result = Value::CreateBooleanValue(value);
+      break;
+    }
+    case Message::INT16: {
+      int16 value = 0;
+      if (reader->PopInt16(&value))
+        result = Value::CreateIntegerValue(value);
+      break;
+    }
+    case Message::UINT16: {
+      uint16 value = 0;
+      if (reader->PopUint16(&value))
+        result = Value::CreateIntegerValue(value);
+      break;
+    }
+    case Message::INT32: {
+      int32 value = 0;
+      if (reader->PopInt32(&value))
+        result = Value::CreateIntegerValue(value);
+      break;
+    }
+    case Message::UINT32: {
+      uint32 value = 0;
+      if (reader->PopUint32(&value))
+        result = Value::CreateDoubleValue(value);
+      break;
+    }
+    case Message::INT64: {
+      int64 value = 0;
+      if (reader->PopInt64(&value)) {
+        DLOG_IF(WARNING, !IsExactlyRepresentableByDouble(value)) <<
+            value << " is not exactly representable by double";
+        result = Value::CreateDoubleValue(value);
+      }
+      break;
+    }
+    case Message::UINT64: {
+      uint64 value = 0;
+      if (reader->PopUint64(&value)) {
+        DLOG_IF(WARNING, !IsExactlyRepresentableByDouble(value)) <<
+            value << " is not exactly representable by double";
+        result = Value::CreateDoubleValue(value);
+      }
+      break;
+    }
+    case Message::DOUBLE: {
+      double value = 0;
+      if (reader->PopDouble(&value))
+        result = Value::CreateDoubleValue(value);
+      break;
+    }
+    case Message::STRING: {
+      std::string value;
+      if (reader->PopString(&value))
+        result = Value::CreateStringValue(value);
+      break;
+    }
+    case Message::OBJECT_PATH: {
+      ObjectPath value;
+      if (reader->PopObjectPath(&value))
+        result = Value::CreateStringValue(value.value());
+      break;
+    }
+    case Message::ARRAY: {
+      MessageReader sub_reader(NULL);
+      if (reader->PopArray(&sub_reader)) {
+        // If the type of the array's element is DICT_ENTRY, create a
+        // DictionaryValue, otherwise create a ListValue.
+        if (sub_reader.GetDataType() == Message::DICT_ENTRY) {
+          scoped_ptr<DictionaryValue> dictionary_value(new DictionaryValue);
+          if (PopDictionaryEntries(&sub_reader, dictionary_value.get()))
+            result = dictionary_value.release();
+        } else {
+          scoped_ptr<ListValue> list_value(new ListValue);
+          if (PopListElements(&sub_reader, list_value.get()))
+            result = list_value.release();
+        }
+      }
+      break;
+    }
+    case Message::STRUCT: {
+      MessageReader sub_reader(NULL);
+      if (reader->PopStruct(&sub_reader)) {
+        scoped_ptr<ListValue> list_value(new ListValue);
+        if (PopListElements(&sub_reader, list_value.get()))
+          result = list_value.release();
+      }
+      break;
+    }
+    case Message::DICT_ENTRY:
+      // DICT_ENTRY must be popped as an element of an array.
+      NOTREACHED();
+      break;
+    case Message::VARIANT: {
+      MessageReader sub_reader(NULL);
+      if (reader->PopVariant(&sub_reader))
+        result = PopDataAsValue(&sub_reader);
+      break;
+    }
+  }
+  return result;
+}
+
+}  // namespace dbus

dbus/values_util.h

@@ -0,0 +1,25 @@
+// 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 DBUS_VALUES_UTIL_H_
+#define DBUS_VALUES_UTIL_H_
+#pragma once
+
+namespace base {
+class Value;
+}
+
+namespace dbus {
+
+class MessageReader;
+
+// Pops a value from |reader| as a base::Value.
+// Returns NULL if an error occurs.
+// Note: Integer values larger than int32 (including uint32) are converted to
+// double.  Non-string diciontary keys are converted to strings.
+base::Value* PopDataAsValue(MessageReader* reader);
+
+}  // namespace dbus
+
+#endif  // DBUS_VALUES_UTIL_H_