shaka-packager/base/json/json_writer.h

84 lines
2.7 KiB
C++

// 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 BASE_JSON_JSON_WRITER_H_
#define BASE_JSON_JSON_WRITER_H_
#include <string>
#include "base/base_export.h"
#include "base/basictypes.h"
namespace base {
class Value;
class BASE_EXPORT JSONWriter {
public:
enum Options {
// Do not escape the string, preserving its UTF8 characters. It is useful
// if you can pass the resulting string to the JSON parser in binary form
// (as UTF8).
OPTIONS_DO_NOT_ESCAPE = 1 << 0,
// For values of binary type, the value (and key if within a dictionary)
// will be omitted from the output.
OPTIONS_OMIT_BINARY_VALUES = 1 << 1,
// This option instructs the writer to write doubles that have no fractional
// part as a normal integer (i.e., without using exponential notation
// or appending a '.0') as long as the value is within the range of a
// 64-bit int.
OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 2,
// Return a slightly nicer formatted json string (pads with whitespace to
// help with readability).
OPTIONS_PRETTY_PRINT = 1 << 3
};
// Given a root node, generates a JSON string and puts it into |json|.
// TODO(tc): Should we generate json if it would be invalid json (e.g.,
// |node| is not a DictionaryValue/ListValue or if there are inf/-inf float
// values)?
static void Write(const Value* const node, std::string* json);
// Same as above but with |options| which is a bunch of JSONWriter::Options
// bitwise ORed together.
static void WriteWithOptions(const Value* const node, int options,
std::string* json);
// A static, constant JSON string representing an empty array. Useful
// for empty JSON argument passing.
static const char* kEmptyArray;
private:
JSONWriter(bool escape, bool omit_binary_values,
bool omit_double_type_preservation, bool pretty_print,
std::string* json);
// Called recursively to build the JSON string. Whe completed, value is
// json_string_ will contain the JSON.
void BuildJSONString(const Value* const node, int depth);
// Appends a quoted, escaped, version of (UTF-8) str to json_string_.
void AppendQuotedString(const std::string& str);
// Adds space to json_string_ for the indent level.
void IndentLine(int depth);
bool escape_;
bool omit_binary_values_;
bool omit_double_type_preservation_;
bool pretty_print_;
// Where we write JSON data as we generate it.
std::string* json_string_;
DISALLOW_COPY_AND_ASSIGN(JSONWriter);
};
} // namespace base
#endif // BASE_JSON_JSON_WRITER_H_