NaCl: Update revision in DEPS, r12488 -> r12497

third_party/jsoncpp/overrides/src/lib_json/json_reader.cpp

Index: third_party/jsoncpp/overrides/src/lib_json/json_reader.cpp
diff --git a/third_party/jsoncpp/overrides/src/lib_json/json_reader.cpp b/third_party/jsoncpp/overrides/src/lib_json/json_reader.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..1bc7429993b7543dd94e6a169c439e27409c98e6
--- /dev/null
+++ b/third_party/jsoncpp/overrides/src/lib_json/json_reader.cpp
@@ -0,0 +1,928 @@
+// Copyright 2007-2011 Baptiste Lepilleur
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#if !defined(JSON_IS_AMALGAMATION)
+# include <json/assertions.h>
+# include <json/reader.h>
+# include <json/value.h>
+# include "json_tool.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+#include <utility>
+#include <cstdio>
+#include <cassert>
+#include <cstring>
+#include <stdexcept>
+#ifdef __pnacl__
+// This file uses the following headers (at least in Reader::parse), but
+// the upstream version doesn't include them because iostream pulls in
+// static initializers.  This breaks the PNaCl build because it uses
+// libc++ which declares getline in <string> (as per the C++ standard)
+// but defines it in <iostream>. The code therefore fails linking, which
+// these includes fix.
+#include <string>
+#include <iostream>
+#endif
+
+#if _MSC_VER >= 1400 // VC++ 8.0
+#pragma warning( disable : 4996 )   // disable warning about strdup being deprecated.
+#endif
+
+namespace Json {
+
+// Implementation of class Features
+// ////////////////////////////////
+
+Features::Features()
+   : allowComments_( true )
+   , strictRoot_( false )
+{
+}
+
+
+Features 
+Features::all()
+{
+   return Features();
+}
+
+
+Features 
+Features::strictMode()
+{
+   Features features;
+   features.allowComments_ = false;
+   features.strictRoot_ = true;
+   return features;
+}
+
+// Implementation of class Reader
+// ////////////////////////////////
+
+
+static inline bool 
+in( Reader::Char c, Reader::Char c1, Reader::Char c2, Reader::Char c3, Reader::Char c4 )
+{
+   return c == c1  ||  c == c2  ||  c == c3  ||  c == c4;
+}
+
+static inline bool 
+in( Reader::Char c, Reader::Char c1, Reader::Char c2, Reader::Char c3, Reader::Char c4, Reader::Char c5 )
+{
+   return c == c1  ||  c == c2  ||  c == c3  ||  c == c4  ||  c == c5;
+}
+
+
+static bool 
+containsNewLine( Reader::Location begin, 
+                 Reader::Location end )
+{
+   for ( ;begin < end; ++begin )
+      if ( *begin == '\n'  ||  *begin == '\r' )
+         return true;
+   return false;
+}
+
+
+// Class Reader
+// //////////////////////////////////////////////////////////////////
+
+Reader::Reader()
+    : errors_(),
+      document_(),
+      begin_(),
+      end_(),
+      current_(),
+      lastValueEnd_(),
+      lastValue_(),
+      commentsBefore_(),
+      features_( Features::all() ),
+      collectComments_()
+{
+}
+
+
+Reader::Reader( const Features &features )
+    : errors_(),
+      document_(),
+      begin_(),
+      end_(),
+      current_(),
+      lastValueEnd_(),
+      lastValue_(),
+      commentsBefore_(),
+      features_( features ),
+      collectComments_()
+{
+}
+
+
+bool
+Reader::parse( const std::string &document, 
+               Value &root,
+               bool collectComments )
+{
+   document_ = document;
+   const char *begin = document_.c_str();
+   const char *end = begin + document_.length();
+   return parse( begin, end, root, collectComments );
+}
+
+
+bool
+Reader::parse( std::istream& sin,
+               Value &root,
+               bool collectComments )
+{
+   //std::istream_iterator<char> begin(sin);
+   //std::istream_iterator<char> end;
+   // Those would allow streamed input from a file, if parse() were a
+   // template function.
+
+   // Since std::string is reference-counted, this at least does not
+   // create an extra copy.
+   std::string doc;
+   std::getline(sin, doc, (char)EOF);
+   return parse( doc, root, collectComments );
+}
+
+bool 
+Reader::parse( const char *beginDoc, const char *endDoc, 
+               Value &root,
+               bool collectComments )
+{
+   if ( !features_.allowComments_ )
+   {
+      collectComments = false;
+   }
+
+   begin_ = beginDoc;
+   end_ = endDoc;
+   collectComments_ = collectComments;
+   current_ = begin_;
+   lastValueEnd_ = 0;
+   lastValue_ = 0;
+   commentsBefore_ = "";
+   errors_.clear();
+   while ( !nodes_.empty() )
+      nodes_.pop();
+   nodes_.push( &root );
+   
+   bool successful = readValue();
+   Token token;
+   skipCommentTokens( token );
+   if ( collectComments_  &&  !commentsBefore_.empty() )
+      root.setComment( commentsBefore_, commentAfter );
+   if ( features_.strictRoot_ )
+   {
+      if ( !root.isArray()  &&  !root.isObject() )
+      {
+         // Set error location to start of doc, ideally should be first token found in doc
+         token.type_ = tokenError;
+         token.start_ = beginDoc;
+         token.end_ = endDoc;
+         addError( "A valid JSON document must be either an array or an object value.",
+                   token );
+         return false;
+      }
+   }
+   return successful;
+}
+
+
+bool
+Reader::readValue()
+{
+   Token token;
+   skipCommentTokens( token );
+   bool successful = true;
+
+   if ( collectComments_  &&  !commentsBefore_.empty() )
+   {
+      currentValue().setComment( commentsBefore_, commentBefore );
+      commentsBefore_ = "";
+   }
+
+
+   switch ( token.type_ )
+   {
+   case tokenObjectBegin:
+      successful = readObject( token );
+      break;
+   case tokenArrayBegin:
+      successful = readArray( token );
+      break;
+   case tokenNumber:
+      successful = decodeNumber( token );
+      break;
+   case tokenString:
+      successful = decodeString( token );
+      break;
+   case tokenTrue:
+      currentValue() = true;
+      break;
+   case tokenFalse:
+      currentValue() = false;
+      break;
+   case tokenNull:
+      currentValue() = Value();
+      break;
+   default:
+      return addError( "Syntax error: value, object or array expected.", token );
+   }
+
+   if ( collectComments_ )
+   {
+      lastValueEnd_ = current_;
+      lastValue_ = &currentValue();
+   }
+
+   return successful;
+}
+
+
+void 
+Reader::skipCommentTokens( Token &token )
+{
+   if ( features_.allowComments_ )
+   {
+      do
+      {
+         readToken( token );
+      }
+      while ( token.type_ == tokenComment );
+   }
+   else
+   {
+      readToken( token );
+   }
+}
+
+
+bool 
+Reader::expectToken( TokenType type, Token &token, const char *message )
+{
+   readToken( token );
+   if ( token.type_ != type )
+      return addError( message, token );
+   return true;
+}
+
+
+bool 
+Reader::readToken( Token &token )
+{
+   skipSpaces();
+   token.start_ = current_;
+   Char c = getNextChar();
+   bool ok = true;
+   switch ( c )
+   {
+   case '{':
+      token.type_ = tokenObjectBegin;
+      break;
+   case '}':
+      token.type_ = tokenObjectEnd;
+      break;
+   case '[':
+      token.type_ = tokenArrayBegin;
+      break;
+   case ']':
+      token.type_ = tokenArrayEnd;
+      break;
+   case '"':
+      token.type_ = tokenString;
+      ok = readString();
+      break;
+   case '/':
+      token.type_ = tokenComment;
+      ok = readComment();
+      break;
+   case '0':
+   case '1':
+   case '2':
+   case '3':
+   case '4':
+   case '5':
+   case '6':
+   case '7':
+   case '8':
+   case '9':
+   case '-':
+      token.type_ = tokenNumber;
+      readNumber();
+      break;
+   case 't':
+      token.type_ = tokenTrue;
+      ok = match( "rue", 3 );
+      break;
+   case 'f':
+      token.type_ = tokenFalse;
+      ok = match( "alse", 4 );
+      break;
+   case 'n':
+      token.type_ = tokenNull;
+      ok = match( "ull", 3 );
+      break;
+   case ',':
+      token.type_ = tokenArraySeparator;
+      break;
+   case ':':
+      token.type_ = tokenMemberSeparator;
+      break;
+   case 0:
+      token.type_ = tokenEndOfStream;
+      break;
+   default:
+      ok = false;
+      break;
+   }
+   if ( !ok )
+      token.type_ = tokenError;
+   token.end_ = current_;
+   return true;
+}
+
+
+void 
+Reader::skipSpaces()
+{
+   while ( current_ != end_ )
+   {
+      Char c = *current_;
+      if ( c == ' '  ||  c == '\t'  ||  c == '\r'  ||  c == '\n' )
+         ++current_;
+      else
+         break;
+   }
+}
+
+
+bool 
+Reader::match( Location pattern, 
+               int patternLength )
+{
+   if ( end_ - current_ < patternLength )
+      return false;
+   int index = patternLength;
+   while ( index-- )
+      if ( current_[index] != pattern[index] )
+         return false;
+   current_ += patternLength;
+   return true;
+}
+
+
+bool
+Reader::readComment()
+{
+   Location commentBegin = current_ - 1;
+   Char c = getNextChar();
+   bool successful = false;
+   if ( c == '*' )
+      successful = readCStyleComment();
+   else if ( c == '/' )
+      successful = readCppStyleComment();
+   if ( !successful )
+      return false;
+
+   if ( collectComments_ )
+   {
+      CommentPlacement placement = commentBefore;
+      if ( lastValueEnd_  &&  !containsNewLine( lastValueEnd_, commentBegin ) )
+      {
+         if ( c != '*'  ||  !containsNewLine( commentBegin, current_ ) )
+            placement = commentAfterOnSameLine;
+      }
+
+      addComment( commentBegin, current_, placement );
+   }
+   return true;
+}
+
+
+void 
+Reader::addComment( Location begin, 
+                    Location end, 
+                    CommentPlacement placement )
+{
+   assert( collectComments_ );
+   if ( placement == commentAfterOnSameLine )
+   {
+      assert( lastValue_ != 0 );
+      lastValue_->setComment( std::string( begin, end ), placement );
+   }
+   else
+   {
+      if ( !commentsBefore_.empty() )
+         commentsBefore_ += "\n";
+      commentsBefore_ += std::string( begin, end );
+   }
+}
+
+
+bool 
+Reader::readCStyleComment()
+{
+   while ( current_ != end_ )
+   {
+      Char c = getNextChar();
+      if ( c == '*'  &&  *current_ == '/' )
+         break;
+   }
+   return getNextChar() == '/';
+}
+
+
+bool 
+Reader::readCppStyleComment()
+{
+   while ( current_ != end_ )
+   {
+      Char c = getNextChar();
+      if (  c == '\r'  ||  c == '\n' )
+         break;
+   }
+   return true;
+}
+
+
+void 
+Reader::readNumber()
+{
+   while ( current_ != end_ )
+   {
+      if ( !(*current_ >= '0'  &&  *current_ <= '9')  &&
+           !in( *current_, '.', 'e', 'E', '+', '-' ) )
+         break;
+      ++current_;
+   }
+}
+
+bool
+Reader::readString()
+{
+   Char c = 0;
+   while ( current_ != end_ )
+   {
+      c = getNextChar();
+      if ( c == '\\' )
+         getNextChar();
+      else if ( c == '"' )
+         break;
+   }
+   return c == '"';
+}
+
+
+bool 
+Reader::readObject( Token &/*tokenStart*/ )
+{
+   Token tokenName;
+   std::string name;
+   currentValue() = Value( objectValue );
+   while ( readToken( tokenName ) )
+   {
+      bool initialTokenOk = true;
+      while ( tokenName.type_ == tokenComment  &&  initialTokenOk )
+         initialTokenOk = readToken( tokenName );
+      if  ( !initialTokenOk )
+         break;
+      if ( tokenName.type_ == tokenObjectEnd  &&  name.empty() )  // empty object
+         return true;
+      if ( tokenName.type_ != tokenString )
+         break;
+      
+      name = "";
+      if ( !decodeString( tokenName, name ) )
+         return recoverFromError( tokenObjectEnd );
+
+      Token colon;
+      if ( !readToken( colon ) ||  colon.type_ != tokenMemberSeparator )
+      {
+         return addErrorAndRecover( "Missing ':' after object member name", 
+                                    colon, 
+                                    tokenObjectEnd );
+      }
+      Value &value = currentValue()[ name ];
+      nodes_.push( &value );
+      bool ok = readValue();
+      nodes_.pop();
+      if ( !ok ) // error already set
+         return recoverFromError( tokenObjectEnd );
+
+      Token comma;
+      if ( !readToken( comma )
+            ||  ( comma.type_ != tokenObjectEnd  &&  
+                  comma.type_ != tokenArraySeparator &&
+                  comma.type_ != tokenComment ) )
+      {
+         return addErrorAndRecover( "Missing ',' or '}' in object declaration", 
+                                    comma, 
+                                    tokenObjectEnd );
+      }
+      bool finalizeTokenOk = true;
+      while ( comma.type_ == tokenComment &&
+              finalizeTokenOk )
+         finalizeTokenOk = readToken( comma );
+      if ( comma.type_ == tokenObjectEnd )
+         return true;
+   }
+   return addErrorAndRecover( "Missing '}' or object member name", 
+                              tokenName, 
+                              tokenObjectEnd );
+}
+
+
+bool 
+Reader::readArray( Token &/*tokenStart*/ )
+{
+   currentValue() = Value( arrayValue );
+   skipSpaces();
+   if ( *current_ == ']' ) // empty array
+   {
+      Token endArray;
+      readToken( endArray );
+      return true;
+   }
+   int index = 0;
+   for (;;)
+   {
+      Value &value = currentValue()[ index++ ];
+      nodes_.push( &value );
+      bool ok = readValue();
+      nodes_.pop();
+      if ( !ok ) // error already set
+         return recoverFromError( tokenArrayEnd );
+
+      Token token;
+      // Accept Comment after last item in the array.
+      ok = readToken( token );
+      while ( token.type_ == tokenComment  &&  ok )
+      {
+         ok = readToken( token );
+      }
+      bool badTokenType = ( token.type_ != tokenArraySeparator  &&
+                            token.type_ != tokenArrayEnd );
+      if ( !ok  ||  badTokenType )
+      {
+         return addErrorAndRecover( "Missing ',' or ']' in array declaration", 
+                                    token, 
+                                    tokenArrayEnd );
+      }
+      if ( token.type_ == tokenArrayEnd )
+         break;
+   }
+   return true;
+}
+
+
+bool 
+Reader::decodeNumber( Token &token )
+{
+   bool isDouble = false;
+   for ( Location inspect = token.start_; inspect != token.end_; ++inspect )
+   {
+      isDouble = isDouble  
+                 ||  in( *inspect, '.', 'e', 'E', '+' )  
+                 ||  ( *inspect == '-'  &&  inspect != token.start_ );
+   }
+   if ( isDouble )
+      return decodeDouble( token );
+   // Attempts to parse the number as an integer. If the number is
+   // larger than the maximum supported value of an integer then
+   // we decode the number as a double.
+   Location current = token.start_;
+   bool isNegative = *current == '-';
+   if ( isNegative )
+      ++current;
+   Value::LargestUInt maxIntegerValue = isNegative ? Value::LargestUInt(-Value::minLargestInt) 
+                                                   : Value::maxLargestUInt;
+   Value::LargestUInt threshold = maxIntegerValue / 10;
+   Value::LargestUInt value = 0;
+   while ( current < token.end_ )
+   {
+      Char c = *current++;
+      if ( c < '0'  ||  c > '9' )
+         return addError( "'" + std::string( token.start_, token.end_ ) + "' is not a number.", token );
+      Value::UInt digit(c - '0');
+      if ( value >= threshold )
+      {
+         // We've hit or exceeded the max value divided by 10 (rounded down). If
+         // a) we've only just touched the limit, b) this is the last digit, and
+         // c) it's small enough to fit in that rounding delta, we're okay.
+         // Otherwise treat this number as a double to avoid overflow.
+         if (value > threshold ||
+             current != token.end_ ||
+             digit > maxIntegerValue % 10)
+         {
+            return decodeDouble( token );
+         }
+      }
+      value = value * 10 + digit;
+   }
+   if ( isNegative )
+      currentValue() = -Value::LargestInt( value );
+   else if ( value <= Value::LargestUInt(Value::maxInt) )
+      currentValue() = Value::LargestInt( value );
+   else
+      currentValue() = value;
+   return true;
+}
+
+
+bool 
+Reader::decodeDouble( Token &token )
+{
+   double value = 0;
+   const int bufferSize = 32;
+   int count;
+   int length = int(token.end_ - token.start_);
+
+   // Sanity check to avoid buffer overflow exploits.
+   if (length < 0) {
+      return addError( "Unable to parse token length", token );
+   }
+
+   // Avoid using a string constant for the format control string given to
+   // sscanf, as this can cause hard to debug crashes on OS X. See here for more
+   // info:
+   //
+   //     http://developer.apple.com/library/mac/#DOCUMENTATION/DeveloperTools/gcc-4.0.1/gcc/Incompatibilities.html
+   char format[] = "%lf";
+
+   if ( length <= bufferSize )
+   {
+      Char buffer[bufferSize+1];
+      memcpy( buffer, token.start_, length );
+      buffer[length] = 0;
+      count = sscanf( buffer, format, &value );
+   }
+   else
+   {
+      std::string buffer( token.start_, token.end_ );
+      count = sscanf( buffer.c_str(), format, &value );
+   }
+
+   if ( count != 1 )
+      return addError( "'" + std::string( token.start_, token.end_ ) + "' is not a number.", token );
+   currentValue() = value;
+   return true;
+}
+
+
+bool 
+Reader::decodeString( Token &token )
+{
+   std::string decoded;
+   if ( !decodeString( token, decoded ) )
+      return false;
+   currentValue() = decoded;
+   return true;
+}
+
+
+bool 
+Reader::decodeString( Token &token, std::string &decoded )
+{
+   decoded.reserve( token.end_ - token.start_ - 2 );
+   Location current = token.start_ + 1; // skip '"'
+   Location end = token.end_ - 1;      // do not include '"'
+   while ( current != end )
+   {
+      Char c = *current++;
+      if ( c == '"' )
+         break;
+      else if ( c == '\\' )
+      {
+         if ( current == end )
+            return addError( "Empty escape sequence in string", token, current );
+         Char escape = *current++;
+         switch ( escape )
+         {
+         case '"': decoded += '"'; break;
+         case '/': decoded += '/'; break;
+         case '\\': decoded += '\\'; break;
+         case 'b': decoded += '\b'; break;
+         case 'f': decoded += '\f'; break;
+         case 'n': decoded += '\n'; break;
+         case 'r': decoded += '\r'; break;
+         case 't': decoded += '\t'; break;
+         case 'u':
+            {
+               unsigned int unicode;
+               if ( !decodeUnicodeCodePoint( token, current, end, unicode ) )
+                  return false;
+               decoded += codePointToUTF8(unicode);
+            }
+            break;
+         default:
+            return addError( "Bad escape sequence in string", token, current );
+         }
+      }
+      else
+      {
+         decoded += c;
+      }
+   }
+   return true;
+}
+
+bool
+Reader::decodeUnicodeCodePoint( Token &token, 
+                                     Location &current, 
+                                     Location end, 
+                                     unsigned int &unicode )
+{
+
+   if ( !decodeUnicodeEscapeSequence( token, current, end, unicode ) )
+      return false;
+   if (unicode >= 0xD800 && unicode <= 0xDBFF)
+   {
+      // surrogate pairs
+      if (end - current < 6)
+         return addError( "additional six characters expected to parse unicode surrogate pair.", token, current );
+      unsigned int surrogatePair;
+      if (*(current++) == '\\' && *(current++)== 'u')
+      {
+         if (decodeUnicodeEscapeSequence( token, current, end, surrogatePair ))
+         {
+            unicode = 0x10000 + ((unicode & 0x3FF) << 10) + (surrogatePair & 0x3FF);
+         } 
+         else
+            return false;
+      } 
+      else
+         return addError( "expecting another \\u token to begin the second half of a unicode surrogate pair", token, current );
+   }
+   return true;
+}
+
+bool 
+Reader::decodeUnicodeEscapeSequence( Token &token, 
+                                     Location &current, 
+                                     Location end, 
+                                     unsigned int &unicode )
+{
+   if ( end - current < 4 )
+      return addError( "Bad unicode escape sequence in string: four digits expected.", token, current );
+   unicode = 0;
+   for ( int index =0; index < 4; ++index )
+   {
+      Char c = *current++;
+      unicode *= 16;
+      if ( c >= '0'  &&  c <= '9' )
+         unicode += c - '0';
+      else if ( c >= 'a'  &&  c <= 'f' )
+         unicode += c - 'a' + 10;
+      else if ( c >= 'A'  &&  c <= 'F' )
+         unicode += c - 'A' + 10;
+      else
+         return addError( "Bad unicode escape sequence in string: hexadecimal digit expected.", token, current );
+   }
+   return true;
+}
+
+
+bool 
+Reader::addError( const std::string &message, 
+                  Token &token,
+                  Location extra )
+{
+   ErrorInfo info;
+   info.token_ = token;
+   info.message_ = message;
+   info.extra_ = extra;
+   errors_.push_back( info );
+   return false;
+}
+
+
+bool 
+Reader::recoverFromError( TokenType skipUntilToken )
+{
+   int errorCount = int(errors_.size());
+   Token skip;
+   for (;;)
+   {
+      if ( !readToken(skip) )
+         errors_.resize( errorCount ); // discard errors caused by recovery
+      if ( skip.type_ == skipUntilToken  ||  skip.type_ == tokenEndOfStream )
+         break;
+   }
+   errors_.resize( errorCount );
+   return false;
+}
+
+
+bool 
+Reader::addErrorAndRecover( const std::string &message, 
+                            Token &token,
+                            TokenType skipUntilToken )
+{
+   addError( message, token );
+   return recoverFromError( skipUntilToken );
+}
+
+
+Value &
+Reader::currentValue()
+{
+   return *(nodes_.top());
+}
+
+
+Reader::Char 
+Reader::getNextChar()
+{
+   if ( current_ == end_ )
+      return 0;
+   return *current_++;
+}
+
+
+void 
+Reader::getLocationLineAndColumn( Location location,
+                                  int &line,
+                                  int &column ) const
+{
+   Location current = begin_;
+   Location lastLineStart = current;
+   line = 0;
+   while ( current < location  &&  current != end_ )
+   {
+      Char c = *current++;
+      if ( c == '\r' )
+      {
+         if ( *current == '\n' )
+            ++current;
+         lastLineStart = current;
+         ++line;
+      }
+      else if ( c == '\n' )
+      {
+         lastLineStart = current;
+         ++line;
+      }
+   }
+   // column & line start at 1
+   column = int(location - lastLineStart) + 1;
+   ++line;
+}
+
+
+std::string
+Reader::getLocationLineAndColumn( Location location ) const
+{
+   int line, column;
+   getLocationLineAndColumn( location, line, column );
+   char buffer[18+16+16+1];
+   sprintf( buffer, "Line %d, Column %d", line, column );
+   return buffer;
+}
+
+
+// Deprecated. Preserved for backward compatibility
+std::string 
+Reader::getFormatedErrorMessages() const
+{
+    return getFormattedErrorMessages();
+}
+
+
+std::string 
+Reader::getFormattedErrorMessages() const
+{
+   std::string formattedMessage;
+   for ( Errors::const_iterator itError = errors_.begin();
+         itError != errors_.end();
+         ++itError )
+   {
+      const ErrorInfo &error = *itError;
+      formattedMessage += "* " + getLocationLineAndColumn( error.token_.start_ ) + "\n";
+      formattedMessage += "  " + error.message_ + "\n";
+      if ( error.extra_ )
+         formattedMessage += "See " + getLocationLineAndColumn( error.extra_ ) + " for detail.\n";
+   }
+   return formattedMessage;
+}
+
+
+std::istream& operator>>( std::istream &sin, Value &root )
+{
+    Json::Reader reader;
+    bool ok = reader.parse(sin, root, true);
+    if (!ok) {
+      fprintf(
+          stderr,
+          "Error from reader: %s",
+          reader.getFormattedErrorMessages().c_str());
+
+      JSON_FAIL_MESSAGE("reader error");
+    }
+    return sin;
+}
+
+
+} // namespace Json