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- // 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 "base/json/json_writer.h"
- #include <stdint.h>
- #include <cmath>
- #include <limits>
- #include "base/json/string_escape.h"
- #include "base/logging.h"
- #include "base/notreached.h"
- #include "base/numerics/safe_conversions.h"
- #include "base/strings/string_number_conversions.h"
- #include "base/strings/utf_string_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, ' ');
- }
- } // namespace base
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