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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/json/json_writer.h"
#include <stdint.h>
#include <cmath>
#include <limits>
#include "base/json/string_escape.h"
#include "base/logging.h"
#include "base/numerics/safe_conversions.h"
#include "base/strings/string_number_conversions.h"
#include "base/values.h"
#include "build/build_config.h"
namespace base {
#if BUILDFLAG(IS_WIN)
const char kPrettyPrintLineEnding[] = "\r\n";
#else
const char kPrettyPrintLineEnding[] = "\n";
#endif
// static
bool JSONWriter::Write(ValueView node, std::string* json, size_t max_depth) {
return WriteWithOptions(node, 0, json, max_depth);
}
// static
bool JSONWriter::WriteWithOptions(ValueView node,
int options,
std::string* json,
size_t max_depth) {
json->clear();
// Is there a better way to estimate the size of the output?
if (json->capacity() < 1024) {
json->reserve(1024);
}
JSONWriter writer(options, json, max_depth);
bool result = node.Visit([&writer](const auto& member) {
return writer.BuildJSONString(member, 0);
});
if (options & OPTIONS_PRETTY_PRINT) {
json->append(kPrettyPrintLineEnding);
}
return result;
}
JSONWriter::JSONWriter(int options, std::string* json, size_t max_depth)
: omit_binary_values_((options & OPTIONS_OMIT_BINARY_VALUES) != 0),
omit_double_type_preservation_(
(options & OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION) != 0),
pretty_print_((options & OPTIONS_PRETTY_PRINT) != 0),
json_string_(json),
max_depth_(max_depth),
stack_depth_(0) {
DCHECK(json);
CHECK_LE(max_depth, internal::kAbsoluteMaxDepth);
}
bool JSONWriter::BuildJSONString(absl::monostate node, size_t depth) {
json_string_->append("null");
return true;
}
bool JSONWriter::BuildJSONString(bool node, size_t depth) {
json_string_->append(node ? "true" : "false");
return true;
}
bool JSONWriter::BuildJSONString(int node, size_t depth) {
json_string_->append(NumberToString(node));
return true;
}
bool JSONWriter::BuildJSONString(double node, size_t depth) {
if (omit_double_type_preservation_ &&
IsValueInRangeForNumericType<int64_t>(node) && std::floor(node) == node) {
json_string_->append(NumberToString(static_cast<int64_t>(node)));
return true;
}
std::string real = NumberToString(node);
// 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_first_of(".eE") == std::string::npos) {
real.append(".0");
}
// The JSON spec requires that non-integer values in the range (-1,1)
// have a zero before the decimal point - ".52" is not valid, "0.52" is.
if (real[0] == '.') {
real.insert(0, 1, '0');
} else if (real.length() > 1 && real[0] == '-' && real[1] == '.') {
// "-.1" bad "-0.1" good
real.insert(1, 1, '0');
}
json_string_->append(real);
return true;
}
bool JSONWriter::BuildJSONString(StringPiece node, size_t depth) {
EscapeJSONString(node, true, json_string_);
return true;
}
bool JSONWriter::BuildJSONString(const Value::BlobStorage& node, size_t depth) {
// Successful only if we're allowed to omit it.
DLOG_IF(ERROR, !omit_binary_values_) << "Cannot serialize binary value.";
return omit_binary_values_;
}
bool JSONWriter::BuildJSONString(const Value::Dict& node, size_t depth) {
internal::StackMarker depth_check(max_depth_, &stack_depth_);
if (depth_check.IsTooDeep()) {
return false;
}
json_string_->push_back('{');
if (pretty_print_) {
json_string_->append(kPrettyPrintLineEnding);
}
bool first_value_has_been_output = false;
bool result = true;
for (const auto [key, value] : node) {
if (omit_binary_values_ && value.type() == Value::Type::BINARY) {
continue;
}
if (first_value_has_been_output) {
json_string_->push_back(',');
if (pretty_print_) {
json_string_->append(kPrettyPrintLineEnding);
}
}
if (pretty_print_) {
IndentLine(depth + 1U);
}
EscapeJSONString(key, true, json_string_);
json_string_->push_back(':');
if (pretty_print_) {
json_string_->push_back(' ');
}
result &= value.Visit([this, depth = depth + 1](const auto& member) {
return BuildJSONString(member, depth);
});
first_value_has_been_output = true;
}
if (pretty_print_) {
if (first_value_has_been_output) {
json_string_->append(kPrettyPrintLineEnding);
}
IndentLine(depth);
}
json_string_->push_back('}');
return result;
}
bool JSONWriter::BuildJSONString(const Value::List& node, size_t depth) {
internal::StackMarker depth_check(max_depth_, &stack_depth_);
if (depth_check.IsTooDeep()) {
return false;
}
json_string_->push_back('[');
if (pretty_print_) {
json_string_->push_back(' ');
}
bool first_value_has_been_output = false;
bool result = true;
for (const auto& value : node) {
if (omit_binary_values_ && value.type() == Value::Type::BINARY) {
continue;
}
if (first_value_has_been_output) {
json_string_->push_back(',');
if (pretty_print_) {
json_string_->push_back(' ');
}
}
result &= value.Visit([this, depth](const auto& member) {
return BuildJSONString(member, depth);
});
first_value_has_been_output = true;
}
if (pretty_print_) {
json_string_->push_back(' ');
}
json_string_->push_back(']');
return result;
}
void JSONWriter::IndentLine(size_t depth) {
json_string_->append(depth * 3U, ' ');
}
absl::optional<std::string> WriteJson(ValueView node, size_t max_depth) {
std::string result;
if (!JSONWriter::Write(node, &result, max_depth)) {
return absl::nullopt;
}
return result;
}
absl::optional<std::string> WriteJsonWithOptions(ValueView node,
uint32_t options,
size_t max_depth) {
std::string result;
if (!JSONWriter::WriteWithOptions(node, static_cast<int>(options), &result,
max_depth)) {
return absl::nullopt;
}
return result;
}
} // namespace base
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