Add dbus::PopDataAsValue

dbus/values_util.cc

Index: dbus/values_util.cc
diff --git a/dbus/values_util.cc b/dbus/values_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..02a542c5e48aa79336ae85149e1bfdf4190514a2
--- /dev/null
+++ b/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 if |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(reader->GetDataType() == Message::DICT_ENTRY);

[satorux1, 2012/03/16 16:23:59]

DCHECK_EQ

[hashimoto, 2012/03/16 16:55:26]

Done.

+    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.

[satorux1, 2012/03/16 16:23:59]

Why? I thought DictionaryValue can have non-strings as keys.

[hashimoto, 2012/03/16 16:55:26]

DictionaryValue's class comment says its keys are string, it there some trick to
use non-strings as keys?
http://code.google.com/codesearch#OAMlx_jo-ck/src/base/values.h&exact_package...

[stevenjb, 2012/03/16 17:51:59]

No, this is correct, DictionaryValue keys are always strings:
typedef std::map<std::string, Value*> ValueMap;

Using JSOMWriter struck me as odd at first, but I can't think of anything better
to use since base::Value doesn't have anything similar. Might be worth adding a
comment to that effect.

[hashimoto, 2012/03/16 18:19:44]

Done.

[satorux1, 2012/03/16 18:28:11]

Oh I see. Then it's likely JSON's spec. Please document about the behavior in
the function comment.

[hashimoto, 2012/03/16 19:21:44]

Done.

+      scoped_ptr<Value> key(PopDataAsValue(&entry_reader));
+      if (!key.get())
+        return false;
+      const bool kPrettyPrint = false;
+      base::JSONWriter::Write(key.get(), kPrettyPrint, &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