blob: 10dd39fd61d5bf6d18067d2bb832f8e24ae3906c [file] [log] [blame]
// Copyright (c) 2006-2008 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 "base/json_writer.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "base/values.h"
#include "base/string_escape.h"
const char kPrettyPrintLineEnding[] = "\r\n";
/* static */
void JSONWriter::Write(const Value* const node, bool pretty_print,
std::string* json) {
json->clear();
// Is there a better way to estimate the size of the output?
json->reserve(1024);
JSONWriter writer(pretty_print, json);
writer.BuildJSONString(node, 0);
if (pretty_print)
json->append(kPrettyPrintLineEnding);
}
JSONWriter::JSONWriter(bool pretty_print, std::string* json)
: json_string_(json),
pretty_print_(pretty_print) {
DCHECK(json);
}
void JSONWriter::BuildJSONString(const Value* const node, int depth) {
switch(node->GetType()) {
case Value::TYPE_NULL:
json_string_->append("null");
break;
case Value::TYPE_BOOLEAN:
{
bool value;
bool result = node->GetAsBoolean(&value);
DCHECK(result);
json_string_->append(value ? "true" : "false");
break;
}
case Value::TYPE_INTEGER:
{
int value;
bool result = node->GetAsInteger(&value);
DCHECK(result);
StringAppendF(json_string_, "%d", value);
break;
}
case Value::TYPE_REAL:
{
double value;
bool result = node->GetAsReal(&value);
DCHECK(result);
std::string real = StringPrintf("%g", value);
// Ensure that the number has a .0 if there's no decimal or 'e'. This
// makes sure that when we read the JSON back, it's interpreted as a
// real rather than an int.
if (real.find('.') == std::string::npos &&
real.find('e') == std::string::npos &&
real.find('E') == std::string::npos) {
real.append(".0");
}
json_string_->append(real);
break;
}
case Value::TYPE_STRING:
{
std::wstring value;
bool result = node->GetAsString(&value);
DCHECK(result);
AppendQuotedString(value);
break;
}
case Value::TYPE_LIST:
{
json_string_->append("[");
if (pretty_print_)
json_string_->append(" ");
const ListValue* list = static_cast<const ListValue*>(node);
for (size_t i = 0; i < list->GetSize(); ++i) {
if (i != 0) {
json_string_->append(",");
if (pretty_print_)
json_string_->append(" ");
}
Value* value = NULL;
bool result = list->Get(i, &value);
DCHECK(result);
BuildJSONString(value, depth);
}
if (pretty_print_)
json_string_->append(" ");
json_string_->append("]");
break;
}
case Value::TYPE_DICTIONARY:
{
json_string_->append("{");
if (pretty_print_)
json_string_->append(kPrettyPrintLineEnding);
const DictionaryValue* dict =
static_cast<const DictionaryValue*>(node);
for (DictionaryValue::key_iterator key_itr = dict->begin_keys();
key_itr != dict->end_keys();
++key_itr) {
if (key_itr != dict->begin_keys()) {
json_string_->append(",");
if (pretty_print_)
json_string_->append(kPrettyPrintLineEnding);
}
Value* value = NULL;
bool result = dict->Get(*key_itr, &value);
DCHECK(result);
if (pretty_print_)
IndentLine(depth + 1);
AppendQuotedString(*key_itr);
if (pretty_print_) {
json_string_->append(": ");
} else {
json_string_->append(":");
}
BuildJSONString(value, depth + 1);
}
if (pretty_print_) {
json_string_->append(kPrettyPrintLineEnding);
IndentLine(depth);
json_string_->append("}");
} else {
json_string_->append("}");
}
break;
}
default:
// TODO(jhughes): handle TYPE_BINARY
NOTREACHED() << "unknown json type";
}
}
void JSONWriter::AppendQuotedString(const std::wstring& str) {
string_escape::JavascriptDoubleQuote(str, true, json_string_);
}
void JSONWriter::IndentLine(int depth) {
// It may be faster to keep an indent string so we don't have to keep
// reallocating.
json_string_->append(std::string(depth * 3, ' '));
}