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Improve Gson and JsonParser trailing data handling
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@Marcono1234
Marcono1234 committed Jun 29, 2022
1 parent cbc0af8 commit ee70912
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Showing 10 changed files with 223 additions and 111 deletions.
61 changes: 29 additions & 32 deletions gson/src/main/java/com/google/gson/Gson.java
View file
Expand Up @@ -38,7 +38,6 @@
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;
import com.google.gson.stream.MalformedJsonException;
import java.io.EOFException;
import java.io.IOException;
import java.io.Reader;
Expand Down Expand Up @@ -983,8 +982,7 @@ public <T> T fromJson(String json, Type typeOfT) throws JsonSyntaxException {
*/
public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException, JsonIOException {
JsonReader jsonReader = newJsonReader(json);
Object object = fromJson(jsonReader, classOfT);
assertFullConsumption(object, jsonReader);
Object object = fromJson(jsonReader, classOfT, true);
return Primitives.wrap(classOfT).cast(object);
}

Expand Down Expand Up @@ -1013,49 +1011,29 @@ public <T> T fromJson(Reader json, Class<T> classOfT) throws JsonSyntaxException
@SuppressWarnings("unchecked")
public <T> T fromJson(Reader json, Type typeOfT) throws JsonIOException, JsonSyntaxException {
JsonReader jsonReader = newJsonReader(json);
T object = (T) fromJson(jsonReader, typeOfT);
assertFullConsumption(object, jsonReader);
T object = (T) fromJson(jsonReader, typeOfT, true);
return object;
}

private static void assertFullConsumption(Object obj, JsonReader reader) {
try {
if (obj != null && reader.peek() != JsonToken.END_DOCUMENT) {
throw new JsonSyntaxException("JSON document was not fully consumed.");
}
} catch (MalformedJsonException e) {
throw new JsonSyntaxException(e);
} catch (IOException e) {
throw new JsonIOException(e);
}
}

/**
* Reads the next JSON value from {@code reader} and convert it to an object
* of type {@code typeOfT}. Returns {@code null}, if the {@code reader} is at EOF.
* Since Type is not parameterized by T, this method is type unsafe and should be used carefully.
*
* <p>Unlike the other {@code fromJson} methods, no exception is thrown if the JSON data has
* multiple top-level JSON elements, or if there is trailing data.
*
* <p>The JSON data is parsed in {@linkplain JsonReader#setLenient(boolean) lenient mode},
* regardless of the lenient mode setting of the provided reader. The lenient mode setting
* of the reader is restored once this method returns.
*
* @throws JsonIOException if there was a problem writing to the Reader
* @throws JsonSyntaxException if json is not a valid representation for an object of type
* @param requireEndDocument whether there must not be any trailing data after
* the first read JSON element
*/
@SuppressWarnings("unchecked")
public <T> T fromJson(JsonReader reader, Type typeOfT) throws JsonIOException, JsonSyntaxException {
private <T> T fromJson(JsonReader reader, Type typeOfT, boolean requireEndDocument) throws JsonIOException, JsonSyntaxException {
boolean isEmpty = true;
boolean oldLenient = reader.isLenient();
reader.setLenient(true);
try {
reader.peek();
isEmpty = false;
@SuppressWarnings("unchecked") // this is not actually safe
TypeToken<T> typeToken = (TypeToken<T>) TypeToken.get(typeOfT);
TypeAdapter<T> typeAdapter = getAdapter(typeToken);
T object = typeAdapter.read(reader);

if (requireEndDocument && reader.peek() != JsonToken.END_DOCUMENT) {
throw new JsonSyntaxException("JSON document was not fully consumed.");
}
return object;
} catch (EOFException e) {
/*
Expand All @@ -1080,6 +1058,25 @@ public <T> T fromJson(JsonReader reader, Type typeOfT) throws JsonIOException, J
}
}

/**
* Reads the next JSON value from {@code reader} and convert it to an object
* of type {@code typeOfT}. Returns {@code null}, if the {@code reader} is at EOF.
* Since Type is not parameterized by T, this method is type unsafe and should be used carefully.
*
* <p>Unlike the other {@code fromJson} methods, no exception is thrown if the JSON data has
* multiple top-level JSON elements, or if there is trailing data.
*
* <p>The JSON data is parsed in {@linkplain JsonReader#setLenient(boolean) lenient mode},
* regardless of the lenient mode setting of the provided reader. The lenient mode setting
* of the reader is restored once this method returns.
*
* @throws JsonIOException if there was a problem writing to the Reader
* @throws JsonSyntaxException if json is not a valid representation for an object of type
*/
public <T> T fromJson(JsonReader reader, Type typeOfT) throws JsonIOException, JsonSyntaxException {
return fromJson(reader, typeOfT, false);
}

/**
* This method deserializes the Json read from the specified parse tree into an object of the
* specified type. It is not suitable to use if the specified class is a generic type since it
Expand Down
47 changes: 19 additions & 28 deletions gson/src/main/java/com/google/gson/JsonParser.java
View file
Expand Up @@ -17,9 +17,6 @@

import com.google.gson.internal.Streams;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.MalformedJsonException;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

Expand All @@ -46,7 +43,7 @@ public JsonParser() {}
* @return a parse tree of {@link JsonElement}s corresponding to the specified JSON
* @throws JsonParseException if the specified text is not valid JSON
*/
public static JsonElement parseString(String json) throws JsonSyntaxException {
public static JsonElement parseString(String json) throws JsonParseException {
return parseReader(new StringReader(json));
}

Expand All @@ -62,20 +59,25 @@ public static JsonElement parseString(String json) throws JsonSyntaxException {
* @throws JsonParseException if there is an IOException or if the specified
* text is not valid JSON
*/
public static JsonElement parseReader(Reader reader) throws JsonIOException, JsonSyntaxException {
public static JsonElement parseReader(Reader reader) throws JsonParseException {
JsonReader jsonReader = new JsonReader(reader);
return parseReader(jsonReader, true);
}

private static JsonElement parseReader(JsonReader reader, boolean requiredEndDocument)
throws JsonParseException {
boolean lenient = reader.isLenient();
reader.setLenient(true);
try {
JsonReader jsonReader = new JsonReader(reader);
JsonElement element = parseReader(jsonReader);
if (!element.isJsonNull() && jsonReader.peek() != JsonToken.END_DOCUMENT) {
throw new JsonSyntaxException("Did not consume the entire document.");
}
return element;
} catch (MalformedJsonException e) {
throw new JsonSyntaxException(e);
} catch (IOException e) {
throw new JsonIOException(e);
return Streams.parse(reader, requiredEndDocument);
} catch (NumberFormatException e) {
throw new JsonSyntaxException(e);
} catch (StackOverflowError e) {
throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
} catch (OutOfMemoryError e) {
throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
} finally {
reader.setLenient(lenient);
}
}

Expand All @@ -91,19 +93,8 @@ public static JsonElement parseReader(Reader reader) throws JsonIOException, Jso
* @throws JsonParseException if there is an IOException or if the specified
* text is not valid JSON
*/
public static JsonElement parseReader(JsonReader reader)
throws JsonIOException, JsonSyntaxException {
boolean lenient = reader.isLenient();
reader.setLenient(true);
try {
return Streams.parse(reader);
} catch (StackOverflowError e) {
throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
} catch (OutOfMemoryError e) {
throw new JsonParseException("Failed parsing JSON source: " + reader + " to Json", e);
} finally {
reader.setLenient(lenient);
}
public static JsonElement parseReader(JsonReader reader) throws JsonParseException {
return parseReader(reader, false);
}

/** @deprecated Use {@link JsonParser#parseString} */
Expand Down
8 changes: 4 additions & 4 deletions gson/src/main/java/com/google/gson/JsonStreamParser.java
View file
Expand Up @@ -61,7 +61,7 @@ public final class JsonStreamParser implements Iterator<JsonElement> {
public JsonStreamParser(String json) {
this(new StringReader(json));
}

/**
* @param reader The data stream containing JSON elements concatenated to each other.
* @since 1.4
Expand All @@ -71,7 +71,7 @@ public JsonStreamParser(Reader reader) {
parser.setLenient(true);
lock = new Object();
}

/**
* Returns the next available {@link JsonElement} on the reader. Throws a
* {@link NoSuchElementException} if no element is available.
Expand All @@ -86,9 +86,9 @@ public JsonElement next() throws JsonParseException {
if (!hasNext()) {
throw new NoSuchElementException();
}

try {
return Streams.parse(parser);
return Streams.parse(parser, false);
} catch (StackOverflowError e) {
throw new JsonParseException("Failed parsing JSON source to Json", e);
} catch (OutOfMemoryError e) {
Expand Down
14 changes: 12 additions & 2 deletions gson/src/main/java/com/google/gson/internal/Streams.java
View file
Expand Up @@ -23,6 +23,7 @@
import com.google.gson.JsonSyntaxException;
import com.google.gson.internal.bind.TypeAdapters;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;
import com.google.gson.stream.MalformedJsonException;
import java.io.EOFException;
Expand All @@ -39,13 +40,22 @@ private Streams() {

/**
* Takes a reader in any state and returns the next value as a JsonElement.
*
* @param requireEndDocument whether there must not be any trailing data after
* the JsonElement
*/
public static JsonElement parse(JsonReader reader) throws JsonParseException {
public static JsonElement parse(JsonReader reader, boolean requireEndDocument) throws JsonParseException {
boolean isEmpty = true;
try {
reader.peek();
isEmpty = false;
return TypeAdapters.JSON_ELEMENT.read(reader);
JsonElement element = TypeAdapters.JSON_ELEMENT.read(reader);

if (requireEndDocument && reader.peek() != JsonToken.END_DOCUMENT) {
throw new JsonSyntaxException("Did not consume the entire document.");
}
return element;

} catch (EOFException e) {
/*
* For compatibility with JSON 1.5 and earlier, we return a JsonNull for
Expand Down
4 changes: 2 additions & 2 deletions gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
View file
Expand Up @@ -62,7 +62,7 @@ public TreeTypeAdapter(JsonSerializer<T> serializer, JsonDeserializer<T> deseria
if (deserializer == null) {
return delegate().read(in);
}
JsonElement value = Streams.parse(in);
JsonElement value = Streams.parse(in, false);
if (value.isJsonNull()) {
return null;
}
Expand Down Expand Up @@ -162,5 +162,5 @@ private final class GsonContextImpl implements JsonSerializationContext, JsonDes
@Override public <R> R deserialize(JsonElement json, Type typeOfT) throws JsonParseException {
return (R) gson.fromJson(json, typeOfT);
}
};
}
}
56 changes: 54 additions & 2 deletions gson/src/test/java/com/google/gson/GsonTest.java
View file
Expand Up @@ -16,11 +16,15 @@

package com.google.gson;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import com.google.gson.internal.Excluder;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import com.google.gson.stream.MalformedJsonException;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.lang.reflect.Field;
Expand All @@ -29,14 +33,14 @@
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import junit.framework.TestCase;
import org.junit.Test;

/**
* Unit tests for {@link Gson}.
*
* @author Ryan Harter
*/
public final class GsonTest extends TestCase {
public final class GsonTest {

private static final Excluder CUSTOM_EXCLUDER = Excluder.DEFAULT
.excludeFieldsWithoutExposeAnnotation()
Expand All @@ -51,6 +55,7 @@ public final class GsonTest extends TestCase {
private static final ToNumberStrategy CUSTOM_OBJECT_TO_NUMBER_STRATEGY = ToNumberPolicy.DOUBLE;
private static final ToNumberStrategy CUSTOM_NUMBER_TO_NUMBER_STRATEGY = ToNumberPolicy.LAZILY_PARSED_NUMBER;

@Test
public void testOverridesDefaultExcluder() {
Gson gson = new Gson(CUSTOM_EXCLUDER, CUSTOM_FIELD_NAMING_STRATEGY,
new HashMap<Type, InstanceCreator<?>>(), true, false, true, false,
Expand All @@ -66,6 +71,7 @@ public void testOverridesDefaultExcluder() {
assertEquals(false, gson.htmlSafe());
}

@Test
public void testClonedTypeAdapterFactoryListsAreIndependent() {
Gson original = new Gson(CUSTOM_EXCLUDER, CUSTOM_FIELD_NAMING_STRATEGY,
new HashMap<Type, InstanceCreator<?>>(), true, false, true, false,
Expand All @@ -89,6 +95,7 @@ private static final class TestTypeAdapter extends TypeAdapter<Object> {
@Override public Object read(JsonReader in) throws IOException { return null; }
}

@Test
public void testNewJsonWriter_Default() throws IOException {
StringWriter writer = new StringWriter();
JsonWriter jsonWriter = new Gson().newJsonWriter(writer);
Expand All @@ -111,6 +118,7 @@ public void testNewJsonWriter_Default() throws IOException {
assertEquals("{\"\\u003ctest2\":true}", writer.toString());
}

@Test
public void testNewJsonWriter_Custom() throws IOException {
StringWriter writer = new StringWriter();
JsonWriter jsonWriter = new GsonBuilder()
Expand All @@ -135,6 +143,7 @@ public void testNewJsonWriter_Custom() throws IOException {
assertEquals(")]}'\n{\n \"test\": null,\n \"<test2\": true\n}1", writer.toString());
}

@Test
public void testNewJsonReader_Default() throws IOException {
String json = "test"; // String without quotes
JsonReader jsonReader = new Gson().newJsonReader(new StringReader(json));
Expand All @@ -146,6 +155,7 @@ public void testNewJsonReader_Default() throws IOException {
jsonReader.close();
}

@Test
public void testNewJsonReader_Custom() throws IOException {
String json = "test"; // String without quotes
JsonReader jsonReader = new GsonBuilder()
Expand All @@ -155,4 +165,46 @@ public void testNewJsonReader_Custom() throws IOException {
assertEquals("test", jsonReader.nextString());
jsonReader.close();
}

@Test
public void testFromJson_Reader_MultipleTopLevel() {
Gson gson = new Gson();
Reader reader = new StringReader("{}1");
try {
gson.fromJson(reader, Object.class);
fail();
} catch (JsonSyntaxException expected) {
assertEquals("JSON document was not fully consumed.", expected.getMessage());
}
}

@Test
public void testFromJson_Reader_MultipleTopLevel_Null() {
Gson gson = new Gson();
Reader reader = new StringReader("null[]");
try {
gson.fromJson(reader, Object.class);
fail();
} catch (JsonSyntaxException expected) {
assertEquals("JSON document was not fully consumed.", expected.getMessage());
}
}

@Test
public void testFromJson_JsonReader_MultipleTopLevel() {
Gson gson = new Gson();
String json = "{}1";
JsonReader jsonReader = new JsonReader(new StringReader(json));
Object object = gson.fromJson(jsonReader, Object.class);
assertEquals(Collections.emptyMap(), object);

object = gson.fromJson(jsonReader, Integer.class);
assertEquals(1, object);

try {
gson.fromJson(jsonReader, Object.class);
fail();
} catch (JsonSyntaxException expected) {
}
}
}

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