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// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
// Distributed under MIT license, or public domain if desired and
// recognized in your jurisdiction.
#ifndef JSON_READER_H_INCLUDED
#define JSON_READER_H_INCLUDED
#if !defined(JSON_IS_AMALGAMATION)
#include "json_features.h"
#include "value.h"
#endif // if !defined(JSON_IS_AMALGAMATION)
#include <deque>
#include <iosfwd>
#include <istream>
#include <stack>
#include <string>
// Disable warning C4251: <data member>: <type> needs to have dll-interface to
// be used by...
#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#pragma warning(push)
#pragma warning(disable : 4251)
#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#pragma pack(push, 8)
namespace Json {
* Value.
*
* \deprecated Use CharReader and CharReaderBuilder.
*/
class JSON_API Reader {
public:
using Char = char;
using Location = const Char*;
/** \brief An error tagged with where in the JSON text it was encountered.
*
* The offsets give the [start, limit) range of bytes within the text. Note
* that this is bytes, not codepoints.
*/
struct StructuredError {
ptrdiff_t offset_start;
ptrdiff_t offset_limit;
String message;
};
/** \brief Constructs a Reader allowing all features for parsing.
* \deprecated Use CharReader and CharReaderBuilder.
*/
Reader();
/** \brief Constructs a Reader allowing the specified feature set for parsing.
* \deprecated Use CharReader and CharReaderBuilder.
*/
Reader(const Features& features);
* document.
*
* \param document UTF-8 encoded string containing the document
* to read.
* \param[out] root Contains the root value of the document if it
* was successfully parsed.
* \param collectComments \c true to collect comment and allow writing
* them back during serialization, \c false to
* discard comments. This parameter is ignored
* if Features::allowComments_ is \c false.
* \return \c true if the document was successfully parsed, \c false if an
* error occurred.
*/
bool parse(const std::string& document, Value& root,
bool collectComments = true);
* document.
*
* \param beginDoc Pointer on the beginning of the UTF-8 encoded
* string of the document to read.
* \param endDoc Pointer on the end of the UTF-8 encoded string
* of the document to read. Must be >= beginDoc.
* \param[out] root Contains the root value of the document if it
* was successfully parsed.
* \param collectComments \c true to collect comment and allow writing
* them back during serialization, \c false to
* discard comments. This parameter is ignored
* if Features::allowComments_ is \c false.
* \return \c true if the document was successfully parsed, \c false if an
* error occurred.
*/
bool parse(const char* beginDoc, const char* endDoc, Value& root,
bool collectComments = true);
/// \brief Parse from input stream.
/// \see Json::operator>>(std::istream&, Json::Value&).
bool parse(IStream& is, Value& root, bool collectComments = true);
/** \brief Returns a user friendly string that list errors in the parsed
* document.
*
* \return Formatted error message with the list of errors with their
* location in the parsed document. An empty string is returned if no error
* occurred during parsing.
* \deprecated Use getFormattedErrorMessages() instead (typo fix).
*/
JSONCPP_DEPRECATED("Use getFormattedErrorMessages() instead.")
String getFormatedErrorMessages() const;
/** \brief Returns a user friendly string that list errors in the parsed
* document.
*
* \return Formatted error message with the list of errors with their
* location in the parsed document. An empty string is returned if no error
* occurred during parsing.
*/
String getFormattedErrorMessages() const;
/** \brief Returns a vector of structured errors encountered while parsing.
*
* \return A (possibly empty) vector of StructuredError objects. Currently
* only one error can be returned, but the caller should tolerate multiple
* errors. This can occur if the parser recovers from a non-fatal parse
* error and then encounters additional errors.
*/
std::vector<StructuredError> getStructuredErrors() const;
/** \brief Add a semantic error message.
*
* \param value JSON Value location associated with the error
* \param message The error message.
* \return \c true if the error was successfully added, \c false if the Value
* offset exceeds the document size.
*/
bool pushError(const Value& value, const String& message);
/** \brief Add a semantic error message with extra context.
*
* \param value JSON Value location associated with the error
* \param message The error message.
* \param extra Additional JSON Value location to contextualize the error
* \return \c true if the error was successfully added, \c false if either
* Value offset exceeds the document size.
*/
bool pushError(const Value& value, const String& message, const Value& extra);
/** \brief Return whether there are any errors.
*
* \return \c true if there are no errors to report \c false if errors have
* occurred.
*/
bool good() const;
private:
enum TokenType {
tokenEndOfStream = 0,
tokenObjectBegin,
tokenObjectEnd,
tokenArrayBegin,
tokenArrayEnd,
tokenString,
tokenNumber,
tokenTrue,
tokenFalse,
tokenNull,
tokenArraySeparator,
tokenMemberSeparator,
tokenComment,
tokenError
};
class Token {
public:
TokenType type_;
Location start_;
Location end_;
};
class ErrorInfo {
public:
Token token_;
String message_;
Location extra_;
};
using Errors = std::deque<ErrorInfo>;
bool readToken(Token& token);
void skipSpaces();
bool match(const Char* pattern, int patternLength);
bool readComment();
bool readCStyleComment();
bool readCppStyleComment();
bool readString();
void readNumber();
bool readValue();
bool readObject(Token& token);
bool readArray(Token& token);
bool decodeNumber(Token& token);
bool decodeNumber(Token& token, Value& decoded);
bool decodeString(Token& token);
bool decodeString(Token& token, String& decoded);
bool decodeDouble(Token& token);
bool decodeDouble(Token& token, Value& decoded);
bool decodeUnicodeCodePoint(Token& token, Location& current, Location end,
unsigned int& unicode);
bool decodeUnicodeEscapeSequence(Token& token, Location& current,
Location end, unsigned int& unicode);
bool addError(const String& message, Token& token, Location extra = nullptr);
bool recoverFromError(TokenType skipUntilToken);
bool addErrorAndRecover(const String& message, Token& token,
TokenType skipUntilToken);
void skipUntilSpace();
Value& currentValue();
Char getNextChar();
void getLocationLineAndColumn(Location location, int& line,
int& column) const;
String getLocationLineAndColumn(Location location) const;
void addComment(Location begin, Location end, CommentPlacement placement);
void skipCommentTokens(Token& token);
static bool containsNewLine(Location begin, Location end);
static String normalizeEOL(Location begin, Location end);
using Nodes = std::stack<Value*>;
Nodes nodes_;
Errors errors_;
String document_;
Location begin_{};
Location end_{};
Location current_{};
Location lastValueEnd_{};
Value* lastValue_{};
String commentsBefore_;
Features features_;
bool collectComments_{};
}; // Reader
/** Interface for reading JSON from a char array.
*/
class JSON_API CharReader {
public:
virtual ~CharReader() = default;
* document. The document must be a UTF-8 encoded string containing the
* document to read.
*
* \param beginDoc Pointer on the beginning of the UTF-8 encoded string
* of the document to read.
* \param endDoc Pointer on the end of the UTF-8 encoded string of the
* document to read. Must be >= beginDoc.
* \param[out] root Contains the root value of the document if it was
* successfully parsed.
* \param[out] errs Formatted error messages (if not NULL) a user
* friendly string that lists errors in the parsed
* document.
* \return \c true if the document was successfully parsed, \c false if an
* error occurred.
*/
virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
String* errs) = 0;
class JSON_API Factory {
public:
virtual ~Factory() = default;
/** \brief Allocate a CharReader via operator new().
* \throw std::exception if something goes wrong (e.g. invalid settings)
*/
virtual CharReader* newCharReader() const = 0;
}; // Factory
}; // CharReader
/** \brief Build a CharReader implementation.
*
* Usage:
* \code
* using namespace Json;
* CharReaderBuilder builder;
* builder["collectComments"] = false;
* Value value;
* String errs;
* bool ok = parseFromStream(builder, std::cin, &value, &errs);
* \endcode
*/
class JSON_API CharReaderBuilder : public CharReader::Factory {
public:
// Note: We use a Json::Value so that we can add data-members to this class
// without a major version bump.
/** Configuration of this builder.
* These are case-sensitive.
* Available settings (case-sensitive):
* - `"collectComments": false or true`
* - true to collect comment and allow writing them back during
* serialization, false to discard comments. This parameter is ignored
* if allowComments is false.
* - `"allowComments": false or true`
* - true if comments are allowed.
* - `"allowTrailingCommas": false or true`
* - true if trailing commas in objects and arrays are allowed.
* - `"strictRoot": false or true`
* - true if root must be either an array or an object value
* - `"allowDroppedNullPlaceholders": false or true`
* - true if dropped null placeholders are allowed. (See
* StreamWriterBuilder.)
* - `"allowNumericKeys": false or true`
* - true if numeric object keys are allowed.
* - `"allowSingleQuotes": false or true`
* - true if '' are allowed for strings (both keys and values)
* - `"stackLimit": integer`
* - Exceeding stackLimit (recursive depth of `readValue()`) will cause an
* exception.
* - This is a security issue (seg-faults caused by deeply nested JSON), so
* the default is low.
* - `"failIfExtra": false or true`
* - If true, `parse()` returns false when extra non-whitespace trails the
* JSON value in the input string.
* - `"rejectDupKeys": false or true`
* - If true, `parse()` returns false when a key is duplicated within an
* object.
* - `"allowSpecialFloats": false or true`
* - If true, special float values (NaNs and infinities) are allowed and
* their values are lossfree restorable.
* - `"skipBom": false or true`
* - If true, if the input starts with the Unicode byte order mark (BOM),
* it is skipped.
*
* You can examine 'settings_` yourself to see the defaults. You can also
* write and read them just like any JSON Value.
* \sa setDefaults()
*/
Json::Value settings_;
CharReaderBuilder();
~CharReaderBuilder() override;
CharReader* newCharReader() const override;
/** \return true if 'settings' are legal and consistent;
* otherwise, indicate bad settings via 'invalid'.
*/
bool validate(Json::Value* invalid) const;
/** A simple way to update a specific setting.
*/
Value& operator[](const String& key);
/** Called by ctor, but you can use this to reset settings_.
* \pre 'settings' != NULL (but Json::null is fine)
* \remark Defaults:
* \snippet src/lib_json/json_reader.cpp CharReaderBuilderDefaults
*/
static void setDefaults(Json::Value* settings);
/** Same as old Features::strictMode().
* \pre 'settings' != NULL (but Json::null is fine)
* \remark Defaults:
* \snippet src/lib_json/json_reader.cpp CharReaderBuilderStrictMode
*/
static void strictMode(Json::Value* settings);
};
/** Consume entire stream and use its begin/end.
* Someday we might have a real StreamReader, but for now this
* is convenient.
*/
bool JSON_API parseFromStream(CharReader::Factory const&, IStream&, Value* root,
String* errs);
/** \brief Read from 'sin' into 'root'.
*
* Always keep comments from the input JSON.
*
* This can be used to read a file into a particular sub-object.
* For example:
* \code
* Json::Value root;
* cin >> root["dir"]["file"];
* cout << root;
* \endcode
* Result:
* \verbatim
* {
* "dir": {
* "file": {
* // The input stream JSON would be nested here.
* }
* }
* }
* \endverbatim
* \throw std::exception on parse error.
* \see Json::operator<<()
*/
JSON_API IStream& operator>>(IStream&, Value&);
} // namespace Json
#pragma pack(pop)
#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#pragma warning(pop)
#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
#endif // JSON_READER_H_INCLUDED