133 lines
4.7 KiB
C++
133 lines
4.7 KiB
C++
// Copyright 2012 The Chromium Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_JSON_JSON_WRITER_H_
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#define BASE_JSON_JSON_WRITER_H_
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#include <stddef.h>
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#include <cstdint>
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#include <string>
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#include "base/base_export.h"
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#include "base/json/json_common.h"
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#include "base/memory/raw_ptr.h"
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#include "base/strings/string_piece.h"
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#include "base/values.h"
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#include "third_party/abseil-cpp/absl/types/optional.h"
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namespace base {
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enum JsonOptions {
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// This option instructs the writer that if a Binary value is encountered,
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// the value (and key if within a dictionary) will be omitted from the
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// output, and success will be returned. Otherwise, if a binary value is
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// encountered, failure will be returned.
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OPTIONS_OMIT_BINARY_VALUES = 1 << 0,
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// This option instructs the writer to write doubles that have no fractional
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// part as a normal integer (i.e., without using exponential notation
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// or appending a '.0') as long as the value is within the range of a
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// 64-bit int.
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OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 1,
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// Return a slightly nicer formatted json string (pads with whitespace to
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// help with readability).
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OPTIONS_PRETTY_PRINT = 1 << 2,
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};
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// Given a root node, generates and returns a JSON string.
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//
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// Returns `absl::nullopt` if
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// * the nesting depth exceeds `max_depth`, or
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// * the JSON contains binary values.
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BASE_EXPORT absl::optional<std::string> WriteJson(
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ValueView node,
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size_t max_depth = internal::kAbsoluteMaxDepth);
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// Given a root node, generates and returns a JSON string.
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// The string is formatted according to `options` which is a bitmask of
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// `JsonOptions`.
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//
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// Returns `absl::nullopt` if
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// * the nesting depth exceeds `max_depth,` or
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// * the JSON contains binary values
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// (unless `JsonOptions::OPTIONS_OMIT_BINARY_VALUES` is passed).
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BASE_EXPORT absl::optional<std::string> WriteJsonWithOptions(
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ValueView node,
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uint32_t options,
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size_t max_depth = internal::kAbsoluteMaxDepth);
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class BASE_EXPORT JSONWriter {
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public:
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using Options = JsonOptions;
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// TODO: Once we support c++20 we replace these with
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// `using enum ::JsonOptions`.
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static constexpr auto OPTIONS_OMIT_BINARY_VALUES =
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JsonOptions::OPTIONS_OMIT_BINARY_VALUES;
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static constexpr auto OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION =
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JsonOptions::OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION;
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static constexpr auto OPTIONS_PRETTY_PRINT =
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JsonOptions::OPTIONS_PRETTY_PRINT;
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JSONWriter(const JSONWriter&) = delete;
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JSONWriter& operator=(const JSONWriter&) = delete;
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// Given a root node, generates a JSON string and puts it into |json|.
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// The output string is overwritten and not appended.
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//
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// TODO(tc): Should we generate json if it would be invalid json (e.g.,
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// |node| is not a dictionary/list Value or if there are inf/-inf float
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// values)? Return true on success and false on failure.
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//
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// Deprecated: use the standalone method `WriteJson()` instead.
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static bool Write(ValueView node,
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std::string* json,
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size_t max_depth = internal::kAbsoluteMaxDepth);
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// Same as above but with |options| which is a bunch of JSONWriter::Options
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// bitwise ORed together. Return true on success and false on failure.
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//
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// Deprecated: use the standalone method `WriteJsonWithOptions()` instead.
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static bool WriteWithOptions(ValueView node,
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int options,
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std::string* json,
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size_t max_depth = internal::kAbsoluteMaxDepth);
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private:
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JSONWriter(int options,
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std::string* json,
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size_t max_depth = internal::kAbsoluteMaxDepth);
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// Called recursively to build the JSON string. When completed,
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// |json_string_| will contain the JSON.
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bool BuildJSONString(absl::monostate node, size_t depth);
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bool BuildJSONString(bool node, size_t depth);
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bool BuildJSONString(int node, size_t depth);
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bool BuildJSONString(double node, size_t depth);
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bool BuildJSONString(StringPiece node, size_t depth);
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bool BuildJSONString(const Value::BlobStorage& node, size_t depth);
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bool BuildJSONString(const Value::Dict& node, size_t depth);
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bool BuildJSONString(const Value::List& node, size_t depth);
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// Adds space to json_string_ for the indent level.
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void IndentLine(size_t depth);
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bool omit_binary_values_;
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bool omit_double_type_preservation_;
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bool pretty_print_;
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// Where we write JSON data as we generate it.
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raw_ptr<std::string> json_string_;
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// Maximum depth to write.
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const size_t max_depth_;
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// The number of times the writer has recursed (current stack depth).
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size_t stack_depth_;
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};
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} // namespace base
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#endif // BASE_JSON_JSON_WRITER_H_
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