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/* * Copyright (C) 2010 Google Inc./* w w w .ja v a 2s . c o m*/ * * 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.google.gson.stream; import com.google.gson.internal.JsonReaderInternalAccess; import com.google.gson.internal.bind.JsonTreeReader; import java.io.Closeable; import java.io.EOFException; import java.io.IOException; import java.io.Reader; /** * 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) throws IOException { * JsonReader reader = new JsonReader(new InputStreamReader(in, "UTF-8")); * try { * return readMessagesArray(reader); * } finally { * reader.close(); * } * } * * public List<Message> readMessagesArray(JsonReader reader) throws IOException { * List<Message> messages = new ArrayList<Message>(); * * reader.beginArray(); * while (reader.hasNext()) { * messages.add(readMessage(reader)); * } * reader.endArray(); * return messages; * } * * public Message readMessage(JsonReader reader) throws IOException { * 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) throws IOException { * List<Double> doubles = new ArrayList<Double>(); * * reader.beginArray(); * while (reader.hasNext()) { * doubles.add(reader.nextDouble()); * } * reader.endArray(); * return doubles; * } * * public User readUser(JsonReader reader) throws IOException { * 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 JsonReader implements Closeable { /** 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 Reader in; /** True to accept non-spec compliant JSON */ private boolean lenient = false; /** * Use a manual buffer to easily read and unread upcoming characters, and * also so we can create strings without an intermediate StringBuilder. * We decode literals directly out of this buffer, so it must be at least as * long as the longest token that can be reported as a number. */ private final char[] buffer = new char[1024]; private int pos = 0; private int limit = 0; 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 int[] stack = new int[32]; private int stackSize = 0; { stack[stackSize++] = JsonScope.EMPTY_DOCUMENT; } /** * Creates a new instance that reads a JSON-encoded stream from {@code in}. */ public JsonReader(Reader in) { if (in == null) { throw new NullPointerException("in == null"); } this.in = in; } /** * 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; } /** * Consumes the next token from the JSON stream and asserts that it is the * beginning of a new array. */ public void beginArray() throws IOException { 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()); } } /** * Consumes the next token from the JSON stream and asserts that it is the * end of the current array. */ public void endArray() throws IOException { 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()); } } /** * Consumes the next token from the JSON stream and asserts that it is the * beginning of a new object. */ public void beginObject() throws IOException { 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()); } } /** * Consumes the next token from the JSON stream and asserts that it is the * end of the current object. */ public void endObject() throws IOException { 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()); } } /** * Returns true if the current array or object has another element. */ public boolean hasNext() throws IOException { int p = peeked; if (p == PEEKED_NONE) { p = doPeek(); } return p != PEEKED_END_OBJECT && p != PEEKED_END_ARRAY; } /** * Returns the type of the next token without consuming it. */ public JsonToken peek() throws IOException { 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() throws IOException { int peekStack = stack[stackSize - 1]; if (peekStack == JsonScope.EMPTY_ARRAY) { stack[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[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[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 || fillBuffer(1)) && buffer[pos] == '>') { pos++; } break; default: throw syntaxError("Expected ':'"); } } else if (peekStack == JsonScope.EMPTY_DOCUMENT) { if (lenient) { consumeNonExecutePrefix(); } stack[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(buffer[pos])) { throw syntaxError("Expected value"); } checkLenient(); return peeked = PEEKED_UNQUOTED; } private int peekKeyword() throws IOException { // Figure out which keyword we're matching against by its first character. char c = buffer[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 && !fillBuffer(i + 1)) { return PEEKED_NONE; } c = buffer[pos + i]; if (c != keyword.charAt(i) && c != keywordUpper.charAt(i)) { return PEEKED_NONE; } } if ((pos + length < limit || fillBuffer(length + 1)) && isLiteral(buffer[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() throws IOException { // Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field access. char[] buffer = this.buffer; int p = pos; int l = limit; 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 (p + i == l) { if (i == buffer.length) { // Though this looks like a well-formed number, it's too long to continue reading. Give up // and let the application handle this as an unquoted literal. return PEEKED_NONE; } if (!fillBuffer(i + 1)) { break; } p = pos; l = limit; } char c = buffer[p + 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) throws IOException { 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; } } /** * Returns the next token, a {@link com.google.gson.stream.JsonToken#NAME property name}, and * consumes it. * * @throws java.io.IOException if the next token in the stream is not a property * name. */ public String nextName() throws IOException { 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; } /** * Returns the {@link com.google.gson.stream.JsonToken#STRING string} value of the next token, * consuming it. If the next token is a number, this method will return its * string form. * * @throws IllegalStateException if the next token is not a string or if * this reader is closed. */ public String nextString() throws IOException { 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 = new String(buffer, pos, peekedNumberLength); pos += peekedNumberLength; } else { throw new IllegalStateException("Expected a string but was " + peek() + " at line " + getLineNumber() + " column " + getColumnNumber()); } peeked = PEEKED_NONE; return result; } /** * Returns the {@link com.google.gson.stream.JsonToken#BOOLEAN boolean} value of the next token, * consuming it. * * @throws IllegalStateException if the next token is not a boolean or if * this reader is closed. */ public boolean nextBoolean() throws IOException { 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()); } /** * Consumes the next token from the JSON stream and asserts that it is a * literal null. * * @throws IllegalStateException if the next token is not null or if this * reader is closed. */ public void nextNull() throws IOException { 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()); } } /** * Returns the {@link com.google.gson.stream.JsonToken#NUMBER double} value of the next token, * consuming it. If the next token is a string, this method will attempt to * parse it as a double using {@link Double#parseDouble(String)}. * * @throws IllegalStateException if the next token is not a literal value. * @throws NumberFormatException if the next literal value cannot be parsed * as a double, or is non-finite. */ public double nextDouble() throws IOException { int p = peeked; if (p == PEEKED_NONE) { p = doPeek(); } if (p == PEEKED_LONG) { peeked = PEEKED_NONE; return (double) peekedLong; } if (p == PEEKED_NUMBER) { peekedString = new String(buffer, 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 new MalformedJsonException("JSON forbids NaN and infinities: " + result + " at line " + getLineNumber() + " column " + getColumnNumber()); } peekedString = null; peeked = PEEKED_NONE; return result; } /** * Returns the {@link com.google.gson.stream.JsonToken#NUMBER long} value of the next token, * consuming it. If the next token is a string, this method will attempt to * parse it as a long. If the next token's numeric value cannot be exactly * represented by a Java {@code long}, this method throws. * * @throws IllegalStateException if the next token is not a literal value. * @throws NumberFormatException if the next literal value cannot be parsed * as a number, or exactly represented as a long. */ public long nextLong() throws IOException { int p = peeked; if (p == PEEKED_NONE) { p = doPeek(); } if (p == PEEKED_LONG) { peeked = PEEKED_NONE; return peekedLong; } if (p == PEEKED_NUMBER) { peekedString = new String(buffer, 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) throws IOException { // Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field access. char[] buffer = this.buffer; StringBuilder builder = new StringBuilder(); while (true) { int p = pos; int l = limit; /* the index of the first character not yet appended to the builder. */ int start = p; while (p < l) { int c = buffer[p++]; if (c == quote) { pos = p; builder.append(buffer, start, p - start - 1); return builder.toString(); } else if (c == '\\') { pos = p; builder.append(buffer, start, p - start - 1); builder.append(readEscapeCharacter()); p = pos; l = limit; start = p; } else if (c == '\n') { lineNumber++; lineStart = p; } } builder.append(buffer, start, p - start); pos = p; if (!fillBuffer(1)) { throw syntaxError("Unterminated string"); } } } /** * Returns an unquoted value as a string. */ @SuppressWarnings("fallthrough") private String nextUnquotedValue() throws IOException { StringBuilder builder = null; int i = 0; findNonLiteralCharacter: while (true) { for (; pos + i < limit; i++) { switch (buffer[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; } } // Attempt to load the entire literal into the buffer at once. if (i < buffer.length) { if (fillBuffer(i + 1)) { continue; } else { break; } } // use a StringBuilder when the value is too long. This is too long to be a number! if (builder == null) { builder = new StringBuilder(); } builder.append(buffer, pos, i); pos += i; i = 0; if (!fillBuffer(1)) { break; } } String result; if (builder == null) { result = new String(buffer, pos, i); } else { builder.append(buffer, pos, i); result = builder.toString(); } pos += i; return result; } private void skipQuotedValue(char quote) throws IOException { // Like nextNonWhitespace, this uses locals 'p' and 'l' to save inner-loop field access. char[] buffer = this.buffer; do { int p = pos; int l = limit; /* the index of the first character not yet appended to the builder. */ while (p < l) { int c = buffer[p++]; if (c == quote) { pos = p; return; } else if (c == '\\') { pos = p; readEscapeCharacter(); p = pos; l = limit; } else if (c == '\n') { lineNumber++; lineStart = p; } } pos = p; } while (fillBuffer(1)); throw syntaxError("Unterminated string"); } private void skipUnquotedValue() throws IOException { do { int i = 0; for (; pos + i < limit; i++) { switch (buffer[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; } while (fillBuffer(1)); } /** * Returns the {@link com.google.gson.stream.JsonToken#NUMBER int} value of the next token, * consuming it. If the next token is a string, this method will attempt to * parse it as an int. If the next token's numeric value cannot be exactly * represented by a Java {@code int}, this method throws. * * @throws IllegalStateException if the next token is not a literal value. * @throws NumberFormatException if the next literal value cannot be parsed * as a number, or exactly represented as an int. */ public int nextInt() throws IOException { 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 = new String(buffer, 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; } /** * Closes this JSON reader and the underlying {@link java.io.Reader}. */ public void close() throws IOException { peeked = PEEKED_NONE; stack[0] = JsonScope.CLOSED; stackSize = 1; in.close(); } /** * Skips the next value recursively. If it is an object or array, all nested * elements are skipped. This method is intended for use when the JSON token * stream contains unrecognized or unhandled values. */ public void skipValue() throws IOException { 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) { if (stackSize == stack.length) { int[] newStack = new int[stackSize * 2]; System.arraycopy(stack, 0, newStack, 0, stackSize); stack = newStack; } stack[stackSize++] = newTop; } /** * Returns true once {@code limit - pos >= minimum}. If the data is * exhausted before that many characters are available, this returns * false. */ private boolean fillBuffer(int minimum) throws IOException { char[] buffer = this.buffer; lineStart -= pos; if (limit != pos) { limit -= pos; System.arraycopy(buffer, pos, buffer, 0, limit); } else { limit = 0; } pos = 0; int total; while ((total = in.read(buffer, limit, buffer.length - limit)) != -1) { limit += total; // if this is the first read, consume an optional byte order mark (BOM) if it exists if (lineNumber == 0 && lineStart == 0 && limit > 0 && buffer[0] == '\ufeff') { pos++; lineStart++; minimum++; } if (limit >= minimum) { return true; } } return false; } private int getLineNumber() { return lineNumber + 1; } private 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) throws IOException { /* * 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. */ char[] buffer = this.buffer; int p = pos; int l = limit; while (true) { if (p == l) { pos = p; if (!fillBuffer(1)) { break; } p = pos; l = limit; } int c = buffer[p++]; if (c == '\n') { lineNumber++; lineStart = p; continue; } else if (c == ' ' || c == '\r' || c == '\t') { continue; } if (c == '/') { pos = p; if (p == l) { pos--; // push back '/' so it's still in the buffer when this method returns boolean charsLoaded = fillBuffer(2); pos++; // consume the '/' again if (!charsLoaded) { return c; } } checkLenient(); char peek = buffer[pos]; switch (peek) { case '*': // skip a /* c-style comment */ pos++; if (!skipTo("*/")) { throw syntaxError("Unterminated comment"); } p = pos + 2; l = limit; continue; case '/': // skip a // end-of-line comment pos++; skipToEndOfLine(); p = pos; l = limit; 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; l = limit; } else { pos = p; return c; } } if (throwOnEof) { throw new EOFException("End of input" + " at line " + getLineNumber() + " column " + getColumnNumber()); } else { return -1; } } private void checkLenient() throws IOException { 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() throws IOException { while (pos < limit || fillBuffer(1)) { char c = buffer[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) throws IOException { outer: for (; pos + toFind.length() <= limit || fillBuffer(toFind.length()); pos++) { if (buffer[pos] == '\n') { lineNumber++; lineStart = pos + 1; continue; } for (int c = 0; c < toFind.length(); c++) { if (buffer[pos + c] != toFind.charAt(c)) { continue outer; } } return true; } return false; } @Override public String toString() { return getClass().getSimpleName() + " 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() throws IOException { if (pos == limit && !fillBuffer(1)) { throw syntaxError("Unterminated escape sequence"); } char escaped = buffer[pos++]; switch (escaped) { case 'u': if (pos + 4 > limit && !fillBuffer(4)) { 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 = buffer[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" + new String(buffer, 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 IOException syntaxError(String message) throws IOException { throw new MalformedJsonException(message + " at line " + getLineNumber() + " column " + getColumnNumber()); } /** * Consumes the non-execute prefix if it exists. */ private void consumeNonExecutePrefix() throws IOException { // fast forward through the leading whitespace nextNonWhitespace(true); pos--; if (pos + NON_EXECUTE_PREFIX.length > limit && !fillBuffer(NON_EXECUTE_PREFIX.length)) { return; } for (int i = 0; i < NON_EXECUTE_PREFIX.length; i++) { if (buffer[pos + i] != NON_EXECUTE_PREFIX[i]) { return; // not a security token! } } // we consumed a security token! pos += NON_EXECUTE_PREFIX.length; } static { JsonReaderInternalAccess.INSTANCE = new JsonReaderInternalAccess() { @Override public void promoteNameToValue(JsonReader reader) throws IOException { if (reader instanceof JsonTreeReader) { ((JsonTreeReader)reader).promoteNameToValue(); return; } int p = reader.peeked; if (p == PEEKED_NONE) { p = reader.doPeek(); } if (p == PEEKED_DOUBLE_QUOTED_NAME) { reader.peeked = PEEKED_DOUBLE_QUOTED; } else if (p == PEEKED_SINGLE_QUOTED_NAME) { reader.peeked = PEEKED_SINGLE_QUOTED; } else if (p == PEEKED_UNQUOTED_NAME) { reader.peeked = PEEKED_UNQUOTED; } else { throw new IllegalStateException("Expected a name but was " + reader.peek() + " " + " at line " + reader.getLineNumber() + " column " + reader.getColumnNumber()); } } }; } }