// 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 #include #include #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(node) && std::floor(node) == node) { json_string_->append(NumberToString(static_cast(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