Merge "Decode JSON literal types eagerly and with our own decoder." (a8bbc11a) · Commits · e / os / android_frameworks_base

core/java/android/util/JsonReader.java

+197 −149

Original line number	Diff line number	Diff line
		@@ -169,6 +169,9 @@ import java.util.List;
		*/
		public final class JsonReader implements Closeable {

		private static final String TRUE = "true";
		private static final String FALSE = "false";

		/** The input JSON. */
		private final Reader in;

		@@ -178,6 +181,8 @@ public final class JsonReader implements Closeable {
		/**
		* 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;
		@@ -188,27 +193,22 @@ public final class JsonReader implements Closeable {
		push(JsonScope.EMPTY_DOCUMENT);
		}

		/**
		* True if we've already read the next token. If we have, the string value
		* for that token will be assigned to {@code value} if such a string value
		* exists. And the token type will be assigned to {@code token} if the token
		* type is known. The token type may be null for literals, since we derive
		* that lazily.
		*/
		private boolean hasToken;

		/**
		* The type of the next token to be returned by {@link #peek} and {@link
		* #advance}, or {@code null} if it is unknown and must first be derived
		* from {@code value}. This value is undefined if {@code hasToken} is false.
		* #advance}. If null, peek() will assign a value.
		*/
		private JsonToken token;

		/** The text of the next name. */
		private String name;

		/** The text of the next literal value. */
		/*
		* For the next literal value, we may have the text value, or the position
		* and length in the buffer.
		*/
		private String value;
		private int valuePos;
		private int valueLength;

		/** True if we're currently handling a skipValue() call. */
		private boolean skipping = false;
		@@ -284,7 +284,7 @@ public final class JsonReader implements Closeable {
		* Consumes {@code expected}.
		*/
		private void expect(JsonToken expected) throws IOException {
		quickPeek();
		peek();
		if (token != expected) {
		throw new IllegalStateException("Expected " + expected + " but was " + peek());
		}
		@@ -295,7 +295,7 @@ public final class JsonReader implements Closeable {
		* Returns true if the current array or object has another element.
		*/
		public boolean hasNext() throws IOException {
		quickPeek();
		peek();
		return token != JsonToken.END_OBJECT && token != JsonToken.END_ARRAY;
		}

		@@ -303,22 +303,7 @@ public final class JsonReader implements Closeable {
		* Returns the type of the next token without consuming it.
		*/
		public JsonToken peek() throws IOException {
		quickPeek();

		if (token == null) {
		decodeLiteral();
		}

		return token;
		}

		/**
		* Ensures that a token is ready. After this call either {@code token} or
		* {@code value} will be non-null. To ensure {@code token} has a definitive
		* value, use {@link #peek()}
		*/
		private JsonToken quickPeek() throws IOException {
		if (hasToken) {
		if (token != null) {
		return token;
		}

		@@ -342,7 +327,6 @@ public final class JsonReader implements Closeable {
		case NONEMPTY_OBJECT:
		return nextInObject(false);
		case NONEMPTY_DOCUMENT:
		hasToken = true;
		return token = JsonToken.END_DOCUMENT;
		case CLOSED:
		throw new IllegalStateException("JsonReader is closed");
		@@ -355,10 +339,9 @@ public final class JsonReader implements Closeable {
		* Advances the cursor in the JSON stream to the next token.
		*/
		private JsonToken advance() throws IOException {
		quickPeek();
		peek();

		JsonToken result = token;
		hasToken = false;
		token = null;
		value = null;
		name = null;
		@@ -373,7 +356,7 @@ public final class JsonReader implements Closeable {
		* name.
		*/
		public String nextName() throws IOException {
		quickPeek();
		peek();
		if (token != JsonToken.NAME) {
		throw new IllegalStateException("Expected a name but was " + peek());
		}
		@@ -392,7 +375,7 @@ public final class JsonReader implements Closeable {
		*/
		public String nextString() throws IOException {
		peek();
		if (value == null \|\| (token != JsonToken.STRING && token != JsonToken.NUMBER)) {
		if (token != JsonToken.STRING && token != JsonToken.NUMBER) {
		throw new IllegalStateException("Expected a string but was " + peek());
		}

		@@ -409,20 +392,12 @@ public final class JsonReader implements Closeable {
		* this reader is closed.
		*/
		public boolean nextBoolean() throws IOException {
		quickPeek();
		if (value == null \|\| token == JsonToken.STRING) {
		throw new IllegalStateException("Expected a boolean but was " + peek());
		}

		boolean result;
		if (value.equalsIgnoreCase("true")) {
		result = true;
		} else if (value.equalsIgnoreCase("false")) {
		result = false;
		} else {
		throw new IllegalStateException("Not a boolean: " + value);
		peek();
		if (token != JsonToken.BOOLEAN) {
		throw new IllegalStateException("Expected a boolean but was " + token);
		}

		boolean result = (value == TRUE);
		advance();
		return result;
		}
		@@ -435,13 +410,9 @@ public final class JsonReader implements Closeable {
		* reader is closed.
		*/
		public void nextNull() throws IOException {
		quickPeek();
		if (value == null \|\| token == JsonToken.STRING) {
		throw new IllegalStateException("Expected null but was " + peek());
		}

		if (!value.equalsIgnoreCase("null")) {
		throw new IllegalStateException("Not a null: " + value);
		peek();
		if (token != JsonToken.NULL) {
		throw new IllegalStateException("Expected null but was " + token);
		}

		advance();
		@@ -450,27 +421,17 @@ public final class JsonReader implements Closeable {
		/**
		* Returns the {@link 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.
		* 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 {
		quickPeek();
		if (value == null) {
		throw new IllegalStateException("Expected a double but was " + peek());
		peek();
		if (token != JsonToken.STRING && token != JsonToken.NUMBER) {
		throw new IllegalStateException("Expected a double but was " + token);
		}

		double result = Double.parseDouble(value);

		if ((result >= 1.0d && value.startsWith("0"))
		\|\| Double.isNaN(result)
		\|\| Double.isInfinite(result)) {
		throw new NumberFormatException(
		"JSON forbids octal prefixes, NaN and infinities: " + value);
		}

		advance();
		return result;
		}
		@@ -486,9 +447,9 @@ public final class JsonReader implements Closeable {
		* as a number, or exactly represented as a long.
		*/
		public long nextLong() throws IOException {
		quickPeek();
		if (value == null) {
		throw new IllegalStateException("Expected a long but was " + peek());
		peek();
		if (token != JsonToken.STRING && token != JsonToken.NUMBER) {
		throw new IllegalStateException("Expected a long but was " + token);
		}

		long result;
		@@ -502,10 +463,6 @@ public final class JsonReader implements Closeable {
		}
		}

		if (result >= 1L && value.startsWith("0")) {
		throw new NumberFormatException("JSON forbids octal prefixes: " + value);
		}

		advance();
		return result;
		}
		@@ -521,9 +478,9 @@ public final class JsonReader implements Closeable {
		* as a number, or exactly represented as an int.
		*/
		public int nextInt() throws IOException {
		quickPeek();
		if (value == null) {
		throw new IllegalStateException("Expected an int but was " + peek());
		peek();
		if (token != JsonToken.STRING && token != JsonToken.NUMBER) {
		throw new IllegalStateException("Expected an int but was " + token);
		}

		int result;
		@@ -537,10 +494,6 @@ public final class JsonReader implements Closeable {
		}
		}

		if (result >= 1L && value.startsWith("0")) {
		throw new NumberFormatException("JSON forbids octal prefixes: " + value);
		}

		advance();
		return result;
		}
		@@ -549,7 +502,6 @@ public final class JsonReader implements Closeable {
		* Closes this JSON reader and the underlying {@link Reader}.
		*/
		public void close() throws IOException {
		hasToken = false;
		value = null;
		token = null;
		stack.clear();
		@@ -606,7 +558,6 @@ public final class JsonReader implements Closeable {
		switch (nextNonWhitespace()) {
		case ']':
		pop();
		hasToken = true;
		return token = JsonToken.END_ARRAY;
		case ';':
		checkLenient(); // fall-through
		@@ -621,7 +572,6 @@ public final class JsonReader implements Closeable {
		case ']':
		if (firstElement) {
		pop();
		hasToken = true;
		return token = JsonToken.END_ARRAY;
		}
		// fall-through to handle ",]"
		@@ -630,7 +580,6 @@ public final class JsonReader implements Closeable {
		/* In lenient mode, a 0-length literal means 'null' */
		checkLenient();
		pos--;
		hasToken = true;
		value = "null";
		return token = JsonToken.NULL;
		default:
		@@ -650,7 +599,6 @@ public final class JsonReader implements Closeable {
		switch (nextNonWhitespace()) {
		case '}':
		pop();
		hasToken = true;
		return token = JsonToken.END_OBJECT;
		default:
		pos--;
		@@ -659,7 +607,6 @@ public final class JsonReader implements Closeable {
		switch (nextNonWhitespace()) {
		case '}':
		pop();
		hasToken = true;
		return token = JsonToken.END_OBJECT;
		case ';':
		case ',':
		@@ -680,14 +627,13 @@ public final class JsonReader implements Closeable {
		default:
		checkLenient();
		pos--;
		name = nextLiteral();
		name = nextLiteral(false);
		if (name.isEmpty()) {
		throw syntaxError("Expected name");
		}
		}

		replaceTop(JsonScope.DANGLING_NAME);
		hasToken = true;
		return token = JsonToken.NAME;
		}

		@@ -718,19 +664,16 @@ public final class JsonReader implements Closeable {
		switch (c) {
		case '{':
		push(JsonScope.EMPTY_OBJECT);
		hasToken = true;
		return token = JsonToken.BEGIN_OBJECT;

		case '[':
		push(JsonScope.EMPTY_ARRAY);
		hasToken = true;
		return token = JsonToken.BEGIN_ARRAY;

		case '\'':
		checkLenient(); // fall-through
		case '"':
		value = nextString((char) c);
		hasToken = true;
		return token = JsonToken.STRING;

		default:
		@@ -899,24 +842,29 @@ public final class JsonReader implements Closeable {
		}

		/**
		* Returns the string up to but not including any delimiter characters. This
		* Reads the value up to but not including any delimiter characters. This
		* does not consume the delimiter character.
		*
		* @param assignOffsetsOnly true for this method to only set the valuePos
		* and valueLength fields and return a null result. This only works if
		* the literal is short; a string is returned otherwise.
		*/
		private String nextLiteral() throws IOException {
		private String nextLiteral(boolean assignOffsetsOnly) throws IOException {
		StringBuilder builder = null;
		do {
		/* the index of the first character not yet appended to the builder. */
		int start = pos;
		while (pos < limit) {
		int c = buffer[pos++];
		switch (c) {
		valuePos = -1;
		valueLength = 0;
		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 '[':
		@@ -928,25 +876,52 @@ public final class JsonReader implements Closeable {
		case '\f':
		case '\r':
		case '\n':
		pos--;
		if (skipping) {
		return "skipped!";
		} else if (builder == null) {
		return new String(buffer, start, pos - start);
		} else {
		builder.append(buffer, start, pos - start);
		return builder.toString();
		break findNonLiteralCharacter;
		}
		}

		/*
		* Attempt to load the entire literal into the buffer at once. If
		* we run out of input, add a non-literal character at the end so
		* that decoding doesn't need to do bounds checks.
		*/
		if (i < buffer.length) {
		if (fillBuffer(i + 1)) {
		continue;
		} else {
		buffer[limit] = '\0';
		break;
		}
		}

		// use a StringBuilder when the value is too long. It must be an unquoted string.
		if (builder == null) {
		builder = new StringBuilder();
		}
		builder.append(buffer, start, pos - start);
		} while (fillBuffer(1));
		builder.append(buffer, pos, i);
		valueLength += i;
		pos += i;
		i = 0;
		if (!fillBuffer(1)) {
		break;
		}
		}

		return builder.toString();
		String result;
		if (assignOffsetsOnly && builder == null) {
		valuePos = pos;
		result = null;
		} else if (skipping) {
		result = "skipped!";
		} else if (builder == null) {
		result = new String(buffer, pos, i);
		} else {
		builder.append(buffer, pos, i);
		result = builder.toString();
		}
		valueLength += i;
		pos += i;
		return result;
		}

		@Override public String toString() {
		@@ -1004,32 +979,105 @@ public final class JsonReader implements Closeable {
		* Reads a null, boolean, numeric or unquoted string literal value.
		*/
		private JsonToken readLiteral() throws IOException {
		String literal = nextLiteral();
		if (literal.isEmpty()) {
		value = nextLiteral(true);
		if (valueLength == 0) {
		throw syntaxError("Expected literal value");
		}
		value = literal;
		hasToken = true;
		return token = null; // use decodeLiteral() to get the token type
		token = decodeLiteral();
		if (token == JsonToken.STRING) {
		checkLenient();
		}
		return token;
		}

		/**
		* Assigns {@code nextToken} based on the value of {@code nextValue}.
		*/
		private void decodeLiteral() throws IOException {
		if (value.equalsIgnoreCase("null")) {
		token = JsonToken.NULL;
		} else if (value.equalsIgnoreCase("true") \|\| value.equalsIgnoreCase("false")) {
		token = JsonToken.BOOLEAN;
		private JsonToken decodeLiteral() throws IOException {
		if (valuePos == -1) {
		// it was too long to fit in the buffer so it can only be a string
		return JsonToken.STRING;
		} else if (valueLength == 4
		&& ('n' == buffer[valuePos ] \|\| 'N' == buffer[valuePos ])
		&& ('u' == buffer[valuePos + 1] \|\| 'U' == buffer[valuePos + 1])
		&& ('l' == buffer[valuePos + 2] \|\| 'L' == buffer[valuePos + 2])
		&& ('l' == buffer[valuePos + 3] \|\| 'L' == buffer[valuePos + 3])) {
		value = "null";
		return JsonToken.NULL;
		} else if (valueLength == 4
		&& ('t' == buffer[valuePos ] \|\| 'T' == buffer[valuePos ])
		&& ('r' == buffer[valuePos + 1] \|\| 'R' == buffer[valuePos + 1])
		&& ('u' == buffer[valuePos + 2] \|\| 'U' == buffer[valuePos + 2])
		&& ('e' == buffer[valuePos + 3] \|\| 'E' == buffer[valuePos + 3])) {
		value = TRUE;
		return JsonToken.BOOLEAN;
		} else if (valueLength == 5
		&& ('f' == buffer[valuePos ] \|\| 'F' == buffer[valuePos ])
		&& ('a' == buffer[valuePos + 1] \|\| 'A' == buffer[valuePos + 1])
		&& ('l' == buffer[valuePos + 2] \|\| 'L' == buffer[valuePos + 2])
		&& ('s' == buffer[valuePos + 3] \|\| 'S' == buffer[valuePos + 3])
		&& ('e' == buffer[valuePos + 4] \|\| 'E' == buffer[valuePos + 4])) {
		value = FALSE;
		return JsonToken.BOOLEAN;
		} else {
		try {
		Double.parseDouble(value); // this work could potentially be cached
		token = JsonToken.NUMBER;
		} catch (NumberFormatException ignored) {
		// this must be an unquoted string
		checkLenient();
		token = JsonToken.STRING;
		value = new String(buffer, valuePos, valueLength);
		return decodeNumber(buffer, valuePos, valueLength);
		}
		}

		/**
		* Determine whether the characters is a JSON number. Numbers are of the
		* form -12.34e+56. Fractional and exponential parts are optional. Leading
		* zeroes are not allowed in the value or exponential part, but are allowed
		* in the fraction.
		*
		* <p>This has a side effect of setting isInteger.
		*/
		private JsonToken decodeNumber(char[] chars, int offset, int length) {
		int i = offset;
		int c = chars[i];

		if (c == '-') {
		c = chars[++i];
		}

		if (c == '0') {
		c = chars[++i];
		} else if (c >= '1' && c <= '9') {
		c = chars[++i];
		while (c >= '0' && c <= '9') {
		c = chars[++i];
		}
		} else {
		return JsonToken.STRING;
		}

		if (c == '.') {
		c = chars[++i];
		while (c >= '0' && c <= '9') {
		c = chars[++i];
		}
		}

		if (c == 'e' \|\| c == 'E') {
		c = chars[++i];
		if (c == '+' \|\| c == '-') {
		c = chars[++i];
		}
		if (c >= '0' && c <= '9') {
		c = chars[++i];
		while (c >= '0' && c <= '9') {
		c = chars[++i];
		}
		} else {
		return JsonToken.STRING;
		}
		}

		if (i == offset + length) {
		return JsonToken.NUMBER;
		} else {
		return JsonToken.STRING;
		}
		}

core/tests/coretests/src/android/util/JsonReaderTest.java

+145 −14

File changed.

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