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package jdk.nashorn.internal.parser;

import java.util.ArrayList;
import java.util.List;
import jdk.nashorn.internal.codegen.ObjectClassGenerator;
import jdk.nashorn.internal.objects.Global;
import jdk.nashorn.internal.runtime.ECMAErrors;
import jdk.nashorn.internal.runtime.ErrorManager;
import jdk.nashorn.internal.runtime.JSErrorType;
import jdk.nashorn.internal.runtime.JSType;
import jdk.nashorn.internal.runtime.ParserException;
import jdk.nashorn.internal.runtime.Property;
import jdk.nashorn.internal.runtime.PropertyMap;
import jdk.nashorn.internal.runtime.ScriptObject;
import jdk.nashorn.internal.runtime.Source;
import jdk.nashorn.internal.runtime.SpillProperty;
import jdk.nashorn.internal.runtime.arrays.ArrayData;
import jdk.nashorn.internal.runtime.arrays.ArrayIndex;
import jdk.nashorn.internal.scripts.JD;
import jdk.nashorn.internal.scripts.JO;

import static jdk.nashorn.internal.parser.TokenType.STRING;

Parses JSON text and returns the corresponding IR node. This is derived from the objectLiteral production of the main parser. See: 15.12.1.2 The JSON Syntactic Grammar
/** * Parses JSON text and returns the corresponding IR node. This is derived from * the objectLiteral production of the main parser. * * See: 15.12.1.2 The JSON Syntactic Grammar */
public class JSONParser { final private String source; final private Global global; final private boolean dualFields; final int length; int pos = 0; private static final int EOF = -1; private static final String TRUE = "true"; private static final String FALSE = "false"; private static final String NULL = "null"; private static final int STATE_EMPTY = 0; private static final int STATE_ELEMENT_PARSED = 1; private static final int STATE_COMMA_PARSED = 2;
Constructor.
Params:
  • source – the source
  • global – the global object
  • dualFields – whether the parser should regard dual field representation
/** * Constructor. * * @param source the source * @param global the global object * @param dualFields whether the parser should regard dual field representation */
public JSONParser(final String source, final Global global, final boolean dualFields) { this.source = source; this.global = global; this.length = source.length(); this.dualFields = dualFields; }
Implementation of the Quote(value) operation as defined in the ECMAscript spec. It wraps a String value in double quotes and escapes characters within.
Params:
  • value – string to quote
Returns:quoted and escaped string
/** * Implementation of the Quote(value) operation as defined in the ECMAscript * spec. It wraps a String value in double quotes and escapes characters * within. * * @param value string to quote * * @return quoted and escaped string */
public static String quote(final String value) { final StringBuilder product = new StringBuilder(); product.append("\""); for (final char ch : value.toCharArray()) { // TODO: should use a table? switch (ch) { case '\\': product.append("\\\\"); break; case '"': product.append("\\\""); break; case '\b': product.append("\\b"); break; case '\f': product.append("\\f"); break; case '\n': product.append("\\n"); break; case '\r': product.append("\\r"); break; case '\t': product.append("\\t"); break; default: if (ch < ' ') { product.append(Lexer.unicodeEscape(ch)); break; } product.append(ch); break; } } product.append("\""); return product.toString(); }
Public parse method. Parse a string into a JSON object.
Returns:the parsed JSON Object
/** * Public parse method. Parse a string into a JSON object. * * @return the parsed JSON Object */
public Object parse() { final Object value = parseLiteral(); skipWhiteSpace(); if (pos < length) { throw expectedError(pos, "eof", toString(peek())); } return value; } private Object parseLiteral() { skipWhiteSpace(); final int c = peek(); if (c == EOF) { throw expectedError(pos, "json literal", "eof"); } switch (c) { case '{': return parseObject(); case '[': return parseArray(); case '"': return parseString(); case 'f': return parseKeyword(FALSE, Boolean.FALSE); case 't': return parseKeyword(TRUE, Boolean.TRUE); case 'n': return parseKeyword(NULL, null); default: if (isDigit(c) || c == '-') { return parseNumber(); } else if (c == '.') { throw numberError(pos); } else { throw expectedError(pos, "json literal", toString(c)); } } } private Object parseObject() { PropertyMap propertyMap = dualFields ? JD.getInitialMap() : JO.getInitialMap(); ArrayData arrayData = ArrayData.EMPTY_ARRAY; final ArrayList<Object> values = new ArrayList<>(); int state = STATE_EMPTY; assert peek() == '{'; pos++; while (pos < length) { skipWhiteSpace(); final int c = peek(); switch (c) { case '"': if (state == STATE_ELEMENT_PARSED) { throw expectedError(pos - 1, ", or }", toString(c)); } final String id = parseString(); expectColon(); final Object value = parseLiteral(); final int index = ArrayIndex.getArrayIndex(id); if (ArrayIndex.isValidArrayIndex(index)) { arrayData = addArrayElement(arrayData, index, value); } else { propertyMap = addObjectProperty(propertyMap, values, id, value); } state = STATE_ELEMENT_PARSED; break; case ',': if (state != STATE_ELEMENT_PARSED) { throw error(AbstractParser.message("trailing.comma.in.json"), pos); } state = STATE_COMMA_PARSED; pos++; break; case '}': if (state == STATE_COMMA_PARSED) { throw error(AbstractParser.message("trailing.comma.in.json"), pos); } pos++; return createObject(propertyMap, values, arrayData); default: throw expectedError(pos, ", or }", toString(c)); } } throw expectedError(pos, ", or }", "eof"); } private static ArrayData addArrayElement(final ArrayData arrayData, final int index, final Object value) { final long oldLength = arrayData.length(); final long longIndex = ArrayIndex.toLongIndex(index); ArrayData newArrayData = arrayData; if (longIndex >= oldLength) { newArrayData = newArrayData.ensure(longIndex); if (longIndex > oldLength) { newArrayData = newArrayData.delete(oldLength, longIndex - 1); } } return newArrayData.set(index, value, false); } private PropertyMap addObjectProperty(final PropertyMap propertyMap, final List<Object> values, final String id, final Object value) { final Property oldProperty = propertyMap.findProperty(id); final PropertyMap newMap; final Class<?> type; final int flags; if (dualFields) { type = getType(value); flags = Property.DUAL_FIELDS; } else { type = Object.class; flags = 0; } if (oldProperty != null) { values.set(oldProperty.getSlot(), value); newMap = propertyMap.replaceProperty(oldProperty, new SpillProperty(id, flags, oldProperty.getSlot(), type));; } else { values.add(value); newMap = propertyMap.addProperty(new SpillProperty(id, flags, propertyMap.size(), type)); } return newMap; } private Object createObject(final PropertyMap propertyMap, final List<Object> values, final ArrayData arrayData) { final long[] primitiveSpill = dualFields ? new long[values.size()] : null; final Object[] objectSpill = new Object[values.size()]; for (final Property property : propertyMap.getProperties()) { if (!dualFields || property.getType() == Object.class) { objectSpill[property.getSlot()] = values.get(property.getSlot()); } else { primitiveSpill[property.getSlot()] = ObjectClassGenerator.pack((Number) values.get(property.getSlot())); } } final ScriptObject object = dualFields ? new JD(propertyMap, primitiveSpill, objectSpill) : new JO(propertyMap, null, objectSpill); object.setInitialProto(global.getObjectPrototype()); object.setArray(arrayData); return object; } private static Class<?> getType(final Object value) { if (value instanceof Integer) { return int.class; } else if (value instanceof Double) { return double.class; } else { return Object.class; } } private void expectColon() { skipWhiteSpace(); final int n = next(); if (n != ':') { throw expectedError(pos - 1, ":", toString(n)); } } private Object parseArray() { ArrayData arrayData = ArrayData.EMPTY_ARRAY; int state = STATE_EMPTY; assert peek() == '['; pos++; while (pos < length) { skipWhiteSpace(); final int c = peek(); switch (c) { case ',': if (state != STATE_ELEMENT_PARSED) { throw error(AbstractParser.message("trailing.comma.in.json"), pos); } state = STATE_COMMA_PARSED; pos++; break; case ']': if (state == STATE_COMMA_PARSED) { throw error(AbstractParser.message("trailing.comma.in.json"), pos); } pos++; return global.wrapAsObject(arrayData); default: if (state == STATE_ELEMENT_PARSED) { throw expectedError(pos, ", or ]", toString(c)); } final long index = arrayData.length(); arrayData = arrayData.ensure(index).set((int) index, parseLiteral(), true); state = STATE_ELEMENT_PARSED; break; } } throw expectedError(pos, ", or ]", "eof"); } private String parseString() { // String buffer is only instantiated if string contains escape sequences. int start = ++pos; StringBuilder sb = null; while (pos < length) { final int c = next(); if (c <= 0x1f) { // Characters < 0x1f are not allowed in JSON strings. throw syntaxError(pos, "String contains control character"); } else if (c == '\\') { if (sb == null) { sb = new StringBuilder(pos - start + 16); } sb.append(source, start, pos - 1); sb.append(parseEscapeSequence()); start = pos; } else if (c == '"') { if (sb != null) { sb.append(source, start, pos - 1); return sb.toString(); } return source.substring(start, pos - 1); } } throw error(Lexer.message("missing.close.quote"), pos, length); } private char parseEscapeSequence() { final int c = next(); switch (c) { case '"': return '"'; case '\\': return '\\'; case '/': return '/'; case 'b': return '\b'; case 'f': return '\f'; case 'n': return '\n'; case 'r': return '\r'; case 't': return '\t'; case 'u': return parseUnicodeEscape(); default: throw error(Lexer.message("invalid.escape.char"), pos - 1, length); } } private char parseUnicodeEscape() { return (char) (parseHexDigit() << 12 | parseHexDigit() << 8 | parseHexDigit() << 4 | parseHexDigit()); } private int parseHexDigit() { final int c = next(); if (c >= '0' && c <= '9') { return c - '0'; } else if (c >= 'A' && c <= 'F') { return c + 10 - 'A'; } else if (c >= 'a' && c <= 'f') { return c + 10 - 'a'; } throw error(Lexer.message("invalid.hex"), pos - 1, length); } private boolean isDigit(final int c) { return c >= '0' && c <= '9'; } private void skipDigits() { while (pos < length) { final int c = peek(); if (!isDigit(c)) { break; } pos++; } } private Number parseNumber() { final int start = pos; int c = next(); if (c == '-') { c = next(); } if (!isDigit(c)) { throw numberError(start); } // no more digits allowed after 0 if (c != '0') { skipDigits(); } // fraction if (peek() == '.') { pos++; if (!isDigit(next())) { throw numberError(pos - 1); } skipDigits(); } // exponent c = peek(); if (c == 'e' || c == 'E') { pos++; c = next(); if (c == '-' || c == '+') { c = next(); } if (!isDigit(c)) { throw numberError(pos - 1); } skipDigits(); } final double d = Double.parseDouble(source.substring(start, pos)); if (JSType.isRepresentableAsInt(d)) { return (int) d; } return d; } private Object parseKeyword(final String keyword, final Object value) { if (!source.regionMatches(pos, keyword, 0, keyword.length())) { throw expectedError(pos, "json literal", "ident"); } pos += keyword.length(); return value; } private int peek() { if (pos >= length) { return -1; } return source.charAt(pos); } private int next() { final int next = peek(); pos++; return next; } private void skipWhiteSpace() { while (pos < length) { switch (peek()) { case '\t': case '\r': case '\n': case ' ': pos++; break; default: return; } } } private static String toString(final int c) { return c == EOF ? "eof" : String.valueOf((char) c); } ParserException error(final String message, final int start, final int length) throws ParserException { final long token = Token.toDesc(STRING, start, length); final int pos = Token.descPosition(token); final Source src = Source.sourceFor("<json>", source); final int lineNum = src.getLine(pos); final int columnNum = src.getColumn(pos); final String formatted = ErrorManager.format(message, src, lineNum, columnNum, token); return new ParserException(JSErrorType.SYNTAX_ERROR, formatted, src, lineNum, columnNum, token); } private ParserException error(final String message, final int start) { return error(message, start, length); } private ParserException numberError(final int start) { return error(Lexer.message("json.invalid.number"), start); } private ParserException expectedError(final int start, final String expected, final String found) { return error(AbstractParser.message("expected", expected, found), start); } private ParserException syntaxError(final int start, final String reason) { final String message = ECMAErrors.getMessage("syntax.error.invalid.json", reason); return error(message, start); } }