//@formatter:off
/*
* Copyright (C) 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.nmorel.gwtjackson.client.stream.impl;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.github.nmorel.gwtjackson.client.exception.JsonDeserializationException;
import com.github.nmorel.gwtjackson.client.stream.JsonToken;
import com.google.gwt.core.client.JsArrayInteger;
/**
* Reads a JSON (<a href="http://www.ietf.org/rfc/rfc4627.txt">RFC 4627</a>)
* encoded value as a stream of tokens. This stream includes both literal
* values (strings, numbers, booleans, and nulls) as well as the begin and
* end delimiters of objects and arrays. The tokens are traversed in
* depth-first order, the same order that they appear in the JSON document.
* Within JSON objects, name/value pairs are represented by a single token.
*
* <h3>Parsing JSON</h3>
* To create a recursive descent parser for your own JSON streams, first create
* an entry point method that creates a {@code JsonReader}.
*
* <p>Next, create handler methods for each structure in your JSON text. You'll
* need a method for each object type and for each array type.
* <ul>
* <li>Within <strong>array handling</strong> methods, first call {@link
* #beginArray} to consume the array's opening bracket. Then create a
* while loop that accumulates values, terminating when {@link #hasNext}
* is false. Finally, read the array's closing bracket by calling {@link
* #endArray}.
* <li>Within <strong>object handling</strong> methods, first call {@link
* #beginObject} to consume the object's opening brace. Then create a
* while loop that assigns values to local variables based on their name.
* This loop should terminate when {@link #hasNext} is false. Finally,
* read the object's closing brace by calling {@link #endObject}.
* </ul>
* <p>When a nested object or array is encountered, delegate to the
* corresponding handler method.
*
* <p>When an unknown name is encountered, strict parsers should fail with an
* exception. Lenient parsers should call {@link #skipValue()} to recursively
* skip the value's nested tokens, which may otherwise conflict.
*
* <p>If a value may be null, you should first check using {@link #peek()}.
* Null literals can be consumed using either {@link #nextNull()} or {@link
* #skipValue()}.
*
* <h3>Example</h3>
* Suppose we'd like to parse a stream of messages such as the following: <pre> {@code
* [
* {
* "id": 912345678901,
* "text": "How do I read a JSON stream in Java?",
* "geo": null,
* "user": {
* "name": "json_newb",
* "followers_count": 41
* }
* },
* {
* "id": 912345678902,
* "text": "@json_newb just use JsonReader!",
* "geo": [50.454722, -104.606667],
* "user": {
* "name": "jesse",
* "followers_count": 2
* }
* }
* ]}</pre>
* This code implements the parser for the above structure: <pre> {@code
*
* public List<Message> readJsonStream(InputStream in) {
* JsonReader reader = new JsonReader(new InputStreamReader(in, "UTF-8"));
* try {
* return readMessagesArray(reader);
* } finally {
* reader.close();
* }
* }
*
* public List<Message> readMessagesArray(JsonReader reader) {
* List<Message> messages = new ArrayList<Message>();
*
* reader.beginArray();
* while (reader.hasNext()) {
* messages.add(readMessage(reader));
* }
* reader.endArray();
* return messages;
* }
*
* public Message readMessage(JsonReader reader) {
* long id = -1;
* String text = null;
* User user = null;
* List<Double> geo = null;
*
* reader.beginObject();
* while (reader.hasNext()) {
* String name = reader.nextName();
* if (name.equals("id")) {
* id = reader.nextLong();
* } else if (name.equals("text")) {
* text = reader.nextString();
* } else if (name.equals("geo") && reader.peek() != JsonToken.NULL) {
* geo = readDoublesArray(reader);
* } else if (name.equals("user")) {
* user = readUser(reader);
* } else {
* reader.skipValue();
* }
* }
* reader.endObject();
* return new Message(id, text, user, geo);
* }
*
* public List<Double> readDoublesArray(JsonReader reader) {
* List<Double> doubles = new ArrayList<Double>();
*
* reader.beginArray();
* while (reader.hasNext()) {
* doubles.add(reader.nextDouble());
* }
* reader.endArray();
* return doubles;
* }
*
* public User readUser(JsonReader reader) {
* String username = null;
* int followersCount = -1;
*
* reader.beginObject();
* while (reader.hasNext()) {
* String name = reader.nextName();
* if (name.equals("name")) {
* username = reader.nextString();
* } else if (name.equals("followers_count")) {
* followersCount = reader.nextInt();
* } else {
* reader.skipValue();
* }
* }
* reader.endObject();
* return new User(username, followersCount);
* }}</pre>
*
* <h3>Number Handling</h3>
* This reader permits numeric values to be read as strings and string values to
* be read as numbers. For example, both elements of the JSON array {@code
* [1, "1"]} may be read using either {@link #nextInt} or {@link #nextString}.
* This behavior is intended to prevent lossy numeric conversions: double is
* JavaScript's only numeric type and very large values like {@code
* 9007199254740993} cannot be represented exactly on that platform. To minimize
* precision loss, extremely large values should be written and read as strings
* in JSON.
*
* <a name="nonexecuteprefix"/><h3>Non-Execute Prefix</h3>
* Web servers that serve private data using JSON may be vulnerable to <a
* href="http://en.wikipedia.org/wiki/JSON#Cross-site_request_forgery">Cross-site
* request forgery</a> attacks. In such an attack, a malicious site gains access
* to a private JSON file by executing it with an HTML {@code <script>} tag.
*
* <p>Prefixing JSON files with <code>")]}'\n"</code> makes them non-executable
* by {@code <script>} tags, disarming the attack. Since the prefix is malformed
* JSON, strict parsing fails when it is encountered. This class permits the
* non-execute prefix when {@link #setLenient(boolean) lenient parsing} is
* enabled.
*
* <p>Each {@code JsonReader} may be used to read a single JSON stream. Instances
* of this class are not thread safe.
*
* @author Jesse Wilson
* @since 1.6
*/
public class NonBufferedJsonReader implements com.github.nmorel.gwtjackson.client.stream.JsonReader
{
private static final Logger logger = Logger.getLogger( "JsonReader" );
/** The only non-execute prefix this parser permits */
private static final char[] NON_EXECUTE_PREFIX = ")]}'\n".toCharArray();
private static final long MIN_INCOMPLETE_INTEGER = Long.MIN_VALUE / 10;
private static final int PEEKED_NONE = 0;
private static final int PEEKED_BEGIN_OBJECT = 1;
private static final int PEEKED_END_OBJECT = 2;
private static final int PEEKED_BEGIN_ARRAY = 3;
private static final int PEEKED_END_ARRAY = 4;
private static final int PEEKED_TRUE = 5;
private static final int PEEKED_FALSE = 6;
private static final int PEEKED_NULL = 7;
private static final int PEEKED_SINGLE_QUOTED = 8;
private static final int PEEKED_DOUBLE_QUOTED = 9;
private static final int PEEKED_UNQUOTED = 10;
/** When this is returned, the string value is stored in peekedString. */
private static final int PEEKED_BUFFERED = 11;
private static final int PEEKED_SINGLE_QUOTED_NAME = 12;
private static final int PEEKED_DOUBLE_QUOTED_NAME = 13;
private static final int PEEKED_UNQUOTED_NAME = 14;
/** When this is returned, the integer value is stored in peekedLong. */
private static final int PEEKED_LONG = 15;
private static final int PEEKED_NUMBER = 16;
private static final int PEEKED_EOF = 17;
/* State machine when parsing numbers */
private static final int NUMBER_CHAR_NONE = 0;
private static final int NUMBER_CHAR_SIGN = 1;
private static final int NUMBER_CHAR_DIGIT = 2;
private static final int NUMBER_CHAR_DECIMAL = 3;
private static final int NUMBER_CHAR_FRACTION_DIGIT = 4;
private static final int NUMBER_CHAR_EXP_E = 5;
private static final int NUMBER_CHAR_EXP_SIGN = 6;
private static final int NUMBER_CHAR_EXP_DIGIT = 7;
/** The input JSON. */
private final String in;
/** True to accept non-spec compliant JSON */
private boolean lenient = false;
private int pos = 0;
private final int limit;
private int lineNumber = 0;
private int lineStart = 0;
private int peeked = PEEKED_NONE;
/**
* A peeked value that was composed entirely of digits with an optional
* leading dash. Positive values may not have a leading 0.
*/
private long peekedLong;
/**
* The number of characters in a peeked number literal. Increment 'pos' by
* this after reading a number.
*/
private int peekedNumberLength;
/**
* A peeked string that should be parsed on the next double, long or string.
* This is populated before a numeric value is parsed and used if that parsing
* fails.
*/
private String peekedString;
/*
* The nesting stack. Using a manual array rather than an ArrayList saves 20%.
*/
private JsArrayInteger stack = JsArrayInteger.createArray().cast();
private int stackSize = 0;
{
stack.set(stackSize++, JsonScope.EMPTY_DOCUMENT);
}
/**
* Creates a new instance that reads a JSON-encoded stream from {@code in}.
*/
public NonBufferedJsonReader( String in ) {
if (in == null) {
throw new NullPointerException("in == null");
}
this.in = in;
this.limit = in.length();
if (limit > 0 && in.charAt( 0 ) == '\ufeff') {
pos++;
lineStart++;
}
}
/**
* Configure this parser to be be liberal in what it accepts. By default,
* this parser is strict and only accepts JSON as specified by <a
* href="http://www.ietf.org/rfc/rfc4627.txt">RFC 4627</a>. Setting the
* parser to lenient causes it to ignore the following syntax errors:
*
* <ul>
* <li>Streams that start with the <a href="#nonexecuteprefix">non-execute
* prefix</a>, <code>")]}'\n"</code>.
* <li>Streams that include multiple top-level values. With strict parsing,
* each stream must contain exactly one top-level value.
* <li>Top-level values of any type. With strict parsing, the top-level
* value must be an object or an array.
* <li>Numbers may be {@link Double#isNaN() NaNs} or {@link
* Double#isInfinite() infinities}.
* <li>End of line comments starting with {@code //} or {@code #} and
* ending with a newline character.
* <li>C-style comments starting with {@code /*} and ending with
* {@code *}{@code /}. Such comments may not be nested.
* <li>Names that are unquoted or {@code 'single quoted'}.
* <li>Strings that are unquoted or {@code 'single quoted'}.
* <li>Array elements separated by {@code ;} instead of {@code ,}.
* <li>Unnecessary array separators. These are interpreted as if null
* was the omitted value.
* <li>Names and values separated by {@code =} or {@code =>} instead of
* {@code :}.
* <li>Name/value pairs separated by {@code ;} instead of {@code ,}.
* </ul>
*/
public final void setLenient( boolean lenient ) {
this.lenient = lenient;
}
/**
* Returns true if this parser is liberal in what it accepts.
*/
public final boolean isLenient() {
return lenient;
}
@Override
public void beginArray()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_BEGIN_ARRAY) {
push(JsonScope.EMPTY_ARRAY);
peeked = PEEKED_NONE;
} else {
throw new IllegalStateException("Expected BEGIN_ARRAY but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
}
@Override
public void endArray()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_END_ARRAY) {
stackSize--;
peeked = PEEKED_NONE;
} else {
throw new IllegalStateException("Expected END_ARRAY but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
}
@Override
public void beginObject()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_BEGIN_OBJECT) {
push(JsonScope.EMPTY_OBJECT);
peeked = PEEKED_NONE;
} else {
throw new IllegalStateException("Expected BEGIN_OBJECT but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
}
@Override
public void endObject()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_END_OBJECT) {
stackSize--;
peeked = PEEKED_NONE;
} else {
throw new IllegalStateException("Expected END_OBJECT but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
}
@Override
public boolean hasNext()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
return p != PEEKED_END_OBJECT && p != PEEKED_END_ARRAY;
}
@Override
public JsonToken peek()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
switch (p) {
case PEEKED_BEGIN_OBJECT:
return JsonToken.BEGIN_OBJECT;
case PEEKED_END_OBJECT:
return JsonToken.END_OBJECT;
case PEEKED_BEGIN_ARRAY:
return JsonToken.BEGIN_ARRAY;
case PEEKED_END_ARRAY:
return JsonToken.END_ARRAY;
case PEEKED_SINGLE_QUOTED_NAME:
case PEEKED_DOUBLE_QUOTED_NAME:
case PEEKED_UNQUOTED_NAME:
return JsonToken.NAME;
case PEEKED_TRUE:
case PEEKED_FALSE:
return JsonToken.BOOLEAN;
case PEEKED_NULL:
return JsonToken.NULL;
case PEEKED_SINGLE_QUOTED:
case PEEKED_DOUBLE_QUOTED:
case PEEKED_UNQUOTED:
case PEEKED_BUFFERED:
return JsonToken.STRING;
case PEEKED_LONG:
case PEEKED_NUMBER:
return JsonToken.NUMBER;
case PEEKED_EOF:
return JsonToken.END_DOCUMENT;
default:
throw new AssertionError();
}
}
private int doPeek()
{
int peekStack = stack.get(stackSize - 1);
if (peekStack == JsonScope.EMPTY_ARRAY) {
stack.set(stackSize - 1, JsonScope.NONEMPTY_ARRAY);
} else if (peekStack == JsonScope.NONEMPTY_ARRAY) {
// Look for a comma before the next element.
int c = nextNonWhitespace(true);
switch (c) {
case ']':
return peeked = PEEKED_END_ARRAY;
case ';':
checkLenient(); // fall-through
case ',':
break;
default:
throw syntaxError("Unterminated array");
}
} else if (peekStack == JsonScope.EMPTY_OBJECT || peekStack == JsonScope.NONEMPTY_OBJECT) {
stack.set(stackSize - 1, JsonScope.DANGLING_NAME);
// Look for a comma before the next element.
if (peekStack == JsonScope.NONEMPTY_OBJECT) {
int c = nextNonWhitespace(true);
switch (c) {
case '}':
return peeked = PEEKED_END_OBJECT;
case ';':
checkLenient(); // fall-through
case ',':
break;
default:
throw syntaxError("Unterminated object");
}
}
int c = nextNonWhitespace(true);
switch (c) {
case '"':
return peeked = PEEKED_DOUBLE_QUOTED_NAME;
case '\'':
checkLenient();
return peeked = PEEKED_SINGLE_QUOTED_NAME;
case '}':
if (peekStack != JsonScope.NONEMPTY_OBJECT) {
return peeked = PEEKED_END_OBJECT;
} else {
throw syntaxError("Expected name");
}
default:
checkLenient();
pos--; // Don't consume the first character in an unquoted string.
if (isLiteral((char) c)) {
return peeked = PEEKED_UNQUOTED_NAME;
} else {
throw syntaxError("Expected name");
}
}
} else if (peekStack == JsonScope.DANGLING_NAME) {
stack.set(stackSize - 1, JsonScope.NONEMPTY_OBJECT);
// Look for a colon before the value.
int c = nextNonWhitespace(true);
switch (c) {
case ':':
break;
case '=':
checkLenient();
if (pos < limit && in.charAt(pos) == '>') {
pos++;
}
break;
default:
throw syntaxError("Expected ':'");
}
} else if (peekStack == JsonScope.EMPTY_DOCUMENT) {
if (lenient) {
consumeNonExecutePrefix();
}
stack.set(stackSize - 1, JsonScope.NONEMPTY_DOCUMENT);
} else if (peekStack == JsonScope.NONEMPTY_DOCUMENT) {
int c = nextNonWhitespace(false);
if (c == -1) {
return peeked = PEEKED_EOF;
} else {
checkLenient();
pos--;
}
} else if (peekStack == JsonScope.CLOSED) {
throw new IllegalStateException("JsonReader is closed");
}
int c = nextNonWhitespace(true);
switch (c) {
case ']':
if (peekStack == JsonScope.EMPTY_ARRAY) {
return peeked = PEEKED_END_ARRAY;
}
// fall-through to handle ",]"
case ';':
case ',':
// In lenient mode, a 0-length literal in an array means 'null'.
if (peekStack == JsonScope.EMPTY_ARRAY || peekStack == JsonScope.NONEMPTY_ARRAY) {
checkLenient();
pos--;
return peeked = PEEKED_NULL;
} else {
throw syntaxError("Unexpected value");
}
case '\'':
checkLenient();
return peeked = PEEKED_SINGLE_QUOTED;
case '"':
if (stackSize == 1) {
checkLenient();
}
return peeked = PEEKED_DOUBLE_QUOTED;
case '[':
return peeked = PEEKED_BEGIN_ARRAY;
case '{':
return peeked = PEEKED_BEGIN_OBJECT;
default:
pos--; // Don't consume the first character in a literal value.
}
if (stackSize == 1) {
checkLenient(); // Top-level value isn't an array or an object.
}
int result = peekKeyword();
if (result != PEEKED_NONE) {
return result;
}
result = peekNumber();
if (result != PEEKED_NONE) {
return result;
}
if (!isLiteral(in.charAt(pos))) {
throw syntaxError("Expected value");
}
checkLenient();
return peeked = PEEKED_UNQUOTED;
}
private int peekKeyword()
{
// Figure out which keyword we're matching against by its first character.
char c = in.charAt(pos);
String keyword;
String keywordUpper;
int peeking;
if (c == 't' || c == 'T') {
keyword = "true";
keywordUpper = "TRUE";
peeking = PEEKED_TRUE;
} else if (c == 'f' || c == 'F') {
keyword = "false";
keywordUpper = "FALSE";
peeking = PEEKED_FALSE;
} else if (c == 'n' || c == 'N') {
keyword = "null";
keywordUpper = "NULL";
peeking = PEEKED_NULL;
} else {
return PEEKED_NONE;
}
// Confirm that chars [1..length) match the keyword.
int length = keyword.length();
for (int i = 1; i < length; i++) {
if (pos + i >= limit) {
return PEEKED_NONE;
}
c = in.charAt(pos + i);
if (c != keyword.charAt(i) && c != keywordUpper.charAt(i)) {
return PEEKED_NONE;
}
}
if (pos + length < limit && isLiteral(in.charAt(pos + length))) {
return PEEKED_NONE; // Don't match trues, falsey or nullsoft!
}
// We've found the keyword followed either by EOF or by a non-literal character.
pos += length;
return peeked = peeking;
}
private int peekNumber()
{
long value = 0; // Negative to accommodate Long.MIN_VALUE more easily.
boolean negative = false;
boolean fitsInLong = true;
int last = NUMBER_CHAR_NONE;
int i = 0;
charactersOfNumber:
for (; true; i++) {
if (pos + i == limit) {
break;
}
char c = in.charAt(pos + i);
switch (c) {
case '-':
if (last == NUMBER_CHAR_NONE) {
negative = true;
last = NUMBER_CHAR_SIGN;
continue;
} else if (last == NUMBER_CHAR_EXP_E) {
last = NUMBER_CHAR_EXP_SIGN;
continue;
}
return PEEKED_NONE;
case '+':
if (last == NUMBER_CHAR_EXP_E) {
last = NUMBER_CHAR_EXP_SIGN;
continue;
}
return PEEKED_NONE;
case 'e':
case 'E':
if (last == NUMBER_CHAR_DIGIT || last == NUMBER_CHAR_FRACTION_DIGIT) {
last = NUMBER_CHAR_EXP_E;
continue;
}
return PEEKED_NONE;
case '.':
if (last == NUMBER_CHAR_DIGIT) {
last = NUMBER_CHAR_DECIMAL;
continue;
}
return PEEKED_NONE;
default:
if (c < '0' || c > '9') {
if (!isLiteral(c)) {
break charactersOfNumber;
}
return PEEKED_NONE;
}
if (last == NUMBER_CHAR_SIGN || last == NUMBER_CHAR_NONE) {
value = -(c - '0');
last = NUMBER_CHAR_DIGIT;
} else if (last == NUMBER_CHAR_DIGIT) {
if (value == 0) {
return PEEKED_NONE; // Leading '0' prefix is not allowed (since it could be octal).
}
long newValue = value * 10 - (c - '0');
fitsInLong &= value > MIN_INCOMPLETE_INTEGER
|| (value == MIN_INCOMPLETE_INTEGER && newValue < value);
value = newValue;
} else if (last == NUMBER_CHAR_DECIMAL) {
last = NUMBER_CHAR_FRACTION_DIGIT;
} else if (last == NUMBER_CHAR_EXP_E || last == NUMBER_CHAR_EXP_SIGN) {
last = NUMBER_CHAR_EXP_DIGIT;
}
}
}
// We've read a complete number. Decide if it's a PEEKED_LONG or a PEEKED_NUMBER.
if (last == NUMBER_CHAR_DIGIT && fitsInLong && (value != Long.MIN_VALUE || negative)) {
peekedLong = negative ? value : -value;
pos += i;
return peeked = PEEKED_LONG;
} else if (last == NUMBER_CHAR_DIGIT || last == NUMBER_CHAR_FRACTION_DIGIT
|| last == NUMBER_CHAR_EXP_DIGIT) {
peekedNumberLength = i;
return peeked = PEEKED_NUMBER;
} else {
return PEEKED_NONE;
}
}
private boolean isLiteral(char c)
{
switch (c) {
case '/':
case '\\':
case ';':
case '#':
case '=':
checkLenient(); // fall-through
case '{':
case '}':
case '[':
case ']':
case ':':
case ',':
case ' ':
case '\t':
case '\f':
case '\r':
case '\n':
return false;
default:
return true;
}
}
@Override
public String nextName()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
String result;
if (p == PEEKED_UNQUOTED_NAME) {
result = nextUnquotedValue();
} else if (p == PEEKED_SINGLE_QUOTED_NAME) {
result = nextQuotedValue('\'');
} else if (p == PEEKED_DOUBLE_QUOTED_NAME) {
result = nextQuotedValue('"');
} else {
throw new IllegalStateException("Expected a name but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peeked = PEEKED_NONE;
return result;
}
@Override
public String nextString()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
String result;
if (p == PEEKED_UNQUOTED) {
result = nextUnquotedValue();
} else if (p == PEEKED_SINGLE_QUOTED) {
result = nextQuotedValue('\'');
} else if (p == PEEKED_DOUBLE_QUOTED) {
result = nextQuotedValue('"');
} else if (p == PEEKED_BUFFERED) {
result = peekedString;
peekedString = null;
} else if (p == PEEKED_LONG) {
result = Long.toString( peekedLong );
} else if (p == PEEKED_NUMBER) {
result = in.substring( pos, pos + peekedNumberLength);
pos += peekedNumberLength;
} else {
throw new IllegalStateException("Expected a string but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peeked = PEEKED_NONE;
return result;
}
@Override
public boolean nextBoolean()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_TRUE) {
peeked = PEEKED_NONE;
return true;
} else if (p == PEEKED_FALSE) {
peeked = PEEKED_NONE;
return false;
}
throw new IllegalStateException("Expected a boolean but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
@Override
public void nextNull()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_NULL) {
peeked = PEEKED_NONE;
} else {
throw new IllegalStateException("Expected null but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
}
@Override
public double nextDouble()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_LONG) {
peeked = PEEKED_NONE;
return (double) peekedLong;
}
if (p == PEEKED_NUMBER) {
peekedString = in.substring(pos, pos + peekedNumberLength);
pos += peekedNumberLength;
} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_DOUBLE_QUOTED) {
peekedString = nextQuotedValue(p == PEEKED_SINGLE_QUOTED ? '\'' : '"');
} else if (p == PEEKED_UNQUOTED) {
peekedString = nextUnquotedValue();
} else if (p != PEEKED_BUFFERED) {
throw new IllegalStateException("Expected a double but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peeked = PEEKED_BUFFERED;
double result = Double.parseDouble( peekedString ); // don't catch this NumberFormatException.
if (!lenient && (Double.isNaN( result ) || Double.isInfinite( result ))) {
throw syntaxError( "JSON forbids NaN and infinities: " + result);
}
peekedString = null;
peeked = PEEKED_NONE;
return result;
}
@Override
public long nextLong()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_LONG) {
peeked = PEEKED_NONE;
return peekedLong;
}
if (p == PEEKED_NUMBER) {
peekedString = in.substring( pos, pos + peekedNumberLength);
pos += peekedNumberLength;
} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_DOUBLE_QUOTED) {
peekedString = nextQuotedValue(p == PEEKED_SINGLE_QUOTED ? '\'' : '"');
try {
long result = Long.parseLong( peekedString );
peeked = PEEKED_NONE;
return result;
} catch (NumberFormatException ignored) {
// Fall back to parse as a double below.
}
} else {
throw new IllegalStateException("Expected a long but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peeked = PEEKED_BUFFERED;
double asDouble = Double.parseDouble( peekedString ); // don't catch this NumberFormatException.
long result = (long) asDouble;
if (result != asDouble) { // Make sure no precision was lost casting to 'long'.
throw new NumberFormatException("Expected a long but was " + peekedString
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peekedString = null;
peeked = PEEKED_NONE;
return result;
}
/**
* Returns the string up to but not including {@code quote}, unescaping any
* character escape sequences encountered along the way. The opening quote
* should have already been read. This consumes the closing quote, but does
* not include it in the returned string.
*
* @param quote either ' or ".
* @throws NumberFormatException if any unicode escape sequences are
* malformed.
*/
private String nextQuotedValue(char quote)
{
// Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field access.
StringBuilder builder = new StringBuilder();
int p = pos;
/* the index of the first character not yet appended to the builder. */
int start = p;
while (p < limit) {
int c = in.charAt(p++);
if (c == quote) {
pos = p;
builder.append(in.substring(start, p - 1));
return builder.toString();
} else if (c == '\\') {
pos = p;
builder.append(in.substring(start, p - 1));
builder.append(readEscapeCharacter());
p = pos;
start = p;
} else if (c == '\n') {
lineNumber++;
lineStart = p;
}
}
throw syntaxError("Unterminated string");
}
/**
* Returns an unquoted value as a string.
*/
@SuppressWarnings("fallthrough")
private String nextUnquotedValue()
{
int i = 0;
findNonLiteralCharacter:
for (; pos + i < limit; i++) {
switch (in.charAt(pos + i)) {
case '/':
case '\\':
case ';':
case '#':
case '=':
checkLenient(); // fall-through
case '{':
case '}':
case '[':
case ']':
case ':':
case ',':
case ' ':
case '\t':
case '\f':
case '\r':
case '\n':
break findNonLiteralCharacter;
}
}
String result = in.substring( pos, pos + i);
pos += i;
return result;
}
private void skipQuotedValue(char quote)
{
// Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field access.
int p = pos;
int l = limit;
/* the index of the first character not yet appended to the builder. */
while (p < l) {
int c = in.charAt(p++);
if (c == quote) {
pos = p;
return;
} else if (c == '\\') {
pos = p;
readEscapeCharacter();
p = pos;
} else if (c == '\n') {
lineNumber++;
lineStart = p;
}
}
throw syntaxError("Unterminated string");
}
private void skipUnquotedValue()
{
int i = 0;
for (; pos + i < limit; i++) {
switch (in.charAt(pos + i)) {
case '/':
case '\\':
case ';':
case '#':
case '=':
checkLenient(); // fall-through
case '{':
case '}':
case '[':
case ']':
case ':':
case ',':
case ' ':
case '\t':
case '\f':
case '\r':
case '\n':
pos += i;
return;
}
}
pos += i;
}
@Override
public int nextInt()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
int result;
if (p == PEEKED_LONG) {
result = (int) peekedLong;
if (peekedLong != result) { // Make sure no precision was lost casting to 'int'.
throw new NumberFormatException("Expected an int but was " + peekedLong
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peeked = PEEKED_NONE;
return result;
}
if (p == PEEKED_NUMBER) {
peekedString = in.substring(pos, pos + peekedNumberLength);
pos += peekedNumberLength;
} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_DOUBLE_QUOTED) {
peekedString = nextQuotedValue(p == PEEKED_SINGLE_QUOTED ? '\'' : '"');
try {
result = Integer.parseInt( peekedString );
peeked = PEEKED_NONE;
return result;
} catch (NumberFormatException ignored) {
// Fall back to parse as a double below.
}
} else {
throw new IllegalStateException("Expected an int but was " + peek()
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peeked = PEEKED_BUFFERED;
double asDouble = Double.parseDouble( peekedString ); // don't catch this NumberFormatException.
result = (int) asDouble;
if (result != asDouble) { // Make sure no precision was lost casting to 'int'.
throw new NumberFormatException("Expected an int but was " + peekedString
+ " at line " + getLineNumber() + " column " + getColumnNumber());
}
peekedString = null;
peeked = PEEKED_NONE;
return result;
}
@Override
public void close()
{
peeked = PEEKED_NONE;
stack.set(0, JsonScope.CLOSED);
stackSize = 1;
}
@Override
public void skipValue()
{
int count = 0;
do {
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_BEGIN_ARRAY) {
push(JsonScope.EMPTY_ARRAY);
count++;
} else if (p == PEEKED_BEGIN_OBJECT) {
push(JsonScope.EMPTY_OBJECT);
count++;
} else if (p == PEEKED_END_ARRAY) {
stackSize--;
count--;
} else if (p == PEEKED_END_OBJECT) {
stackSize--;
count--;
} else if (p == PEEKED_UNQUOTED_NAME || p == PEEKED_UNQUOTED) {
skipUnquotedValue();
} else if (p == PEEKED_SINGLE_QUOTED || p == PEEKED_SINGLE_QUOTED_NAME) {
skipQuotedValue('\'');
} else if (p == PEEKED_DOUBLE_QUOTED || p == PEEKED_DOUBLE_QUOTED_NAME) {
skipQuotedValue('"');
} else if (p == PEEKED_NUMBER) {
pos += peekedNumberLength;
}
peeked = PEEKED_NONE;
} while (count != 0);
}
private void push(int newTop) {
stack.set(stackSize++, newTop);
}
@Override
public int getLineNumber() {
return lineNumber + 1;
}
@Override
public int getColumnNumber() {
return pos - lineStart + 1;
}
/**
* Returns the next character in the stream that is neither whitespace nor a
* part of a comment. When this returns, the returned character is always at
* {@code buffer[pos-1]}; this means the caller can always push back the
* returned character by decrementing {@code pos}.
*/
private int nextNonWhitespace(boolean throwOnEof)
{
/*
* This code uses ugly local variables 'p' and 'l' representing the 'pos'
* and 'limit' fields respectively. Using locals rather than fields saves
* a few field reads for each whitespace character in a pretty-printed
* document, resulting in a 5% speedup. We need to flush 'p' to its field
* before any (potentially indirect) call to fillBuffer() and reread both
* 'p' and 'l' after any (potentially indirect) call to the same method.
*/
int p = pos;
while (true) {
if (p == limit) {
pos = p;
break;
}
int c = in.charAt(p++);
if (c == '\n') {
lineNumber++;
lineStart = p;
continue;
} else if (c == ' ' || c == '\r' || c == '\t') {
continue;
}
if (c == '/') {
pos = p;
if (p == limit) {
return c;
}
checkLenient();
char peek = in.charAt(pos);
switch (peek) {
case '*':
// skip a /* c-style comment */
pos++;
if (!skipTo("*/")) {
throw syntaxError("Unterminated comment");
}
p = pos + 2;
continue;
case '/':
// skip a // end-of-line comment
pos++;
skipToEndOfLine();
p = pos;
continue;
default:
return c;
}
} else if (c == '#') {
pos = p;
/*
* Skip a # hash end-of-line comment. The JSON RFC doesn't
* specify this behaviour, but it's required to parse
* existing documents. See http://b/2571423.
*/
checkLenient();
skipToEndOfLine();
p = pos;
} else {
pos = p;
return c;
}
}
if (throwOnEof) {
String mess = "End of input at line " + getLineNumber() + " column " + getColumnNumber();
logger.log(Level.SEVERE, mess);
throw new JsonDeserializationException(mess);
} else {
return -1;
}
}
private void checkLenient()
{
if (!lenient) {
throw syntaxError("Use JsonReader.setLenient(true) to accept malformed JSON");
}
}
/**
* Advances the position until after the next newline character. If the line
* is terminated by "\r\n", the '\n' must be consumed as whitespace by the
* caller.
*/
private void skipToEndOfLine()
{
while (pos < limit) {
char c = in.charAt(pos++);
if (c == '\n') {
lineNumber++;
lineStart = pos;
break;
} else if (c == '\r') {
break;
}
}
}
/**
* @param toFind a string to search for. Must not contain a newline.
*/
private boolean skipTo(String toFind)
{
outer:
for (; pos + toFind.length() <= limit; pos++) {
if (in.charAt(pos) == '\n') {
lineNumber++;
lineStart = pos + 1;
continue;
}
for (int c = 0; c < toFind.length(); c++) {
if (in.charAt(pos + c) != toFind.charAt(c)) {
continue outer;
}
}
return true;
}
return false;
}
@Override
public String toString() {
return "JsonReader at line " + getLineNumber() + " column " + getColumnNumber();
}
/**
* Unescapes the character identified by the character or characters that
* immediately follow a backslash. The backslash '\' should have already
* been read. This supports both unicode escapes "u000A" and two-character
* escapes "\n".
*
* @throws NumberFormatException if any unicode escape sequences are
* malformed.
*/
private char readEscapeCharacter()
{
if (pos == limit) {
throw syntaxError("Unterminated escape sequence");
}
char escaped = in.charAt(pos++);
switch (escaped) {
case 'u':
if (pos + 4 > limit) {
throw syntaxError("Unterminated escape sequence");
}
// Equivalent to Integer.parseInt(stringPool.get(buffer, pos, 4), 16);
char result = 0;
for (int i = pos, end = i + 4; i < end; i++) {
char c = in.charAt(i);
result <<= 4;
if (c >= '0' && c <= '9') {
result += (c - '0');
} else if (c >= 'a' && c <= 'f') {
result += (c - 'a' + 10);
} else if (c >= 'A' && c <= 'F') {
result += (c - 'A' + 10);
} else {
throw new NumberFormatException("\\u" + in.substring(pos, pos + 4));
}
}
pos += 4;
return result;
case 't':
return '\t';
case 'b':
return '\b';
case 'n':
return '\n';
case 'r':
return '\r';
case 'f':
return '\f';
case '\n':
lineNumber++;
lineStart = pos;
// fall-through
case '\'':
case '"':
case '\\':
default:
return escaped;
}
}
/**
* Throws a new IO exception with the given message and a context snippet
* with this reader's content.
*/
private MalformedJsonException syntaxError(String message)
{
String mess = message + " at line " + getLineNumber() + " column " + getColumnNumber();
logger.log(Level.SEVERE, mess);
throw new MalformedJsonException(mess);
}
/**
* Consumes the non-execute prefix if it exists.
*/
private void consumeNonExecutePrefix()
{
// fast forward through the leading whitespace
nextNonWhitespace(true);
pos--;
if (pos + NON_EXECUTE_PREFIX.length > limit) {
return;
}
for (int i = 0; i < NON_EXECUTE_PREFIX.length; i++) {
if (in.charAt(pos + i) != NON_EXECUTE_PREFIX[i]) {
return; // not a security token!
}
}
// we consumed a security token!
pos += NON_EXECUTE_PREFIX.length;
}
@Override
public String getInput(){
return in;
}
@Override
public String nextValue()
{
int p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if(p == PEEKED_NULL) {
peeked = PEEKED_NONE;
return "null";
}
StringBuilder builder = new StringBuilder();
int count = 0;
do {
p = peeked;
if (p == PEEKED_NONE) {
p = doPeek();
}
if (p == PEEKED_BEGIN_ARRAY) {
push(JsonScope.EMPTY_ARRAY);
count++;
builder.append('[');
} else if (p == PEEKED_BEGIN_OBJECT) {
push(JsonScope.EMPTY_OBJECT);
count++;
builder.append('{');
} else if (p == PEEKED_END_ARRAY) {
stackSize--;
count--;
builder.append(']');
} else if (p == PEEKED_END_OBJECT) {
stackSize--;
count--;
builder.append('}');
} else if (p == PEEKED_UNQUOTED_NAME) {
builder.append(nextUnquotedValue());
builder.append(':');
} else if (p == PEEKED_SINGLE_QUOTED_NAME) {
builder.append('\'');
builder.append(nextQuotedValue( '\'' ));
builder.append('\'');
builder.append(':');
} else if (p == PEEKED_DOUBLE_QUOTED_NAME) {
builder.append('"');
builder.append(nextQuotedValue( '"' ));
builder.append('"');
builder.append(':');
} else if (p == PEEKED_UNQUOTED) {
builder.append(nextUnquotedValue());
} else if (p == PEEKED_SINGLE_QUOTED) {
builder.append('\'');
builder.append(nextQuotedValue( '\'' ));
builder.append('\'');
} else if (p == PEEKED_DOUBLE_QUOTED) {
builder.append('"');
builder.append(nextQuotedValue( '"' ));
builder.append('"');
} else if (p == PEEKED_NUMBER) {
builder.append( in.substring( pos, pos + peekedNumberLength) );
pos += peekedNumberLength;
} else if (p == PEEKED_TRUE) {
builder.append( true );
} else if (p == PEEKED_FALSE) {
builder.append( false );
} else if (p == PEEKED_LONG) {
builder.append( peekedLong );
} else if (p == PEEKED_BUFFERED) {
builder.append( peekedString );
}
peeked = PEEKED_NONE;
} while (count != 0);
return builder.toString();
}
}
//@formatter:on