[Java][FlexBuffers] Deprecate typed vector strings due to design flaw (#5722)

* [Java][FlexBuffers] Deprecate typed vector strings due to design flaw

It will still be possible to read buffers with this type, but the
elements will be treated as FBT_KEY and will be read as null-terminated
string.

Trying to build a vector of strings as typed will throw an exception.

More information on https://github.com/google/flatbuffers/issues/5627

Also, fix another bug on strings, where long strings were not properly
aligned.

* [Java][FlexBuffers] Make FBT_VECTOR_STRING_DEPRECATED considered typed.

The logic for FlexBuffers.isVectorType() was changed
to not consider FBT_VECTOR_STRING_DEPRECATED a typed
vector, but that can lead to missinterpretation for
existing serialized data. So we are reverting.
This commit is contained in:
Paulo Pinheiro
2020-01-24 18:58:15 +01:00
committed by Wouter van Oortmerssen
parent a593a11e59
commit 3f677f2414
3 changed files with 106 additions and 26 deletions

View File

@@ -12,6 +12,10 @@ import com.google.flatbuffers.FlexBuffers;
import com.google.flatbuffers.FlexBuffersBuilder;
import com.google.flatbuffers.StringVector;
import com.google.flatbuffers.UnionVector;
import com.google.flatbuffers.FlexBuffers.FlexBufferException;
import com.google.flatbuffers.FlexBuffers.Reference;
import com.google.flatbuffers.FlexBuffers.Vector;
import java.io.*;
import java.math.BigInteger;
import java.nio.ByteBuffer;
@@ -694,6 +698,60 @@ class JavaTest {
TestEq(mymap.get("blob").toString(), "\"AC\"");
}
public static void testFlexBufferVectorStrings() {
FlexBuffersBuilder builder = new FlexBuffersBuilder(ByteBuffer.allocate(10000000));
int size = 3000;
StringBuilder sb = new StringBuilder();
for (int i=0; i< size; i++) {
sb.append("a");
}
String text = sb.toString();
TestEq(text.length(), size);
int pos = builder.startVector();
for (int i=0; i<size; i++) {
builder.putString(text);
}
try {
builder.endVector(null, pos, true, false);
// this should raise an exception as
// typed vector of string was deprecated
assert false;
} catch(FlexBufferException fb) {
// no op
}
// we finish the vector again as non-typed
builder.endVector(null, pos, false, false);
ByteBuffer b = builder.finish();
Vector v = FlexBuffers.getRoot(b).asVector();
TestEq(v.size(), size);
for (int i=0; i<size; i++) {
TestEq(v.get(i).asString().length(), size);
TestEq(v.get(i).asString(), text);
}
}
public static void testDeprecatedTypedVectorString() {
// tests whether we are able to support reading deprecated typed vector string
// data is equivalent to [ "abc", "abc", "abc", "abc"]
byte[] data = new byte[] {0x03, 0x61, 0x62, 0x63, 0x00, 0x03, 0x61, 0x62, 0x63, 0x00,
0x03, 0x61, 0x62, 0x63, 0x00, 0x03, 0x61, 0x62, 0x63, 0x00, 0x04, 0x14, 0x10,
0x0c, 0x08, 0x04, 0x3c, 0x01};
Reference ref = FlexBuffers.getRoot(ByteBuffer.wrap(data));
TestEq(ref.getType(), FlexBuffers.FBT_VECTOR_STRING_DEPRECATED);
TestEq(ref.isTypedVector(), true);
Vector vec = ref.asVector();
for (int i=0; i< vec.size(); i++) {
TestEq("abc", vec.get(i).asString());
}
}
public static void testSingleElementBoolean() {
FlexBuffersBuilder builder = new FlexBuffersBuilder(ByteBuffer.allocate(100));
builder.putBoolean(true);
@@ -743,13 +801,32 @@ class JavaTest {
TestEq(Double.compare(Double.MAX_VALUE, FlexBuffers.getRoot(b).asFloat()), 0);
}
public static void testSingleElementString() {
FlexBuffersBuilder builder = new FlexBuffersBuilder();
builder.putString("wow");
public static void testSingleElementBigString() {
FlexBuffersBuilder builder = new FlexBuffersBuilder(ByteBuffer.allocate(10000));
StringBuilder sb = new StringBuilder();
for (int i=0; i< 3000; i++) {
sb.append("a");
}
builder.putString(sb.toString());
ByteBuffer b = builder.finish();
FlexBuffers.Reference r = FlexBuffers.getRoot(b);
TestEq(FlexBuffers.FBT_STRING, r.getType());
TestEq(sb.toString(), r.asString());
}
public static void testSingleElementSmallString() {
FlexBuffersBuilder builder = new FlexBuffersBuilder(ByteBuffer.allocate(10000));
builder.putString("aa");
ByteBuffer b = builder.finish();
FlexBuffers.Reference r = FlexBuffers.getRoot(b);
TestEq(FlexBuffers.FBT_STRING, r.getType());
TestEq("wow", r.asString());
TestEq("aa", r.asString());
}
public static void testSingleElementBlob() {
@@ -813,12 +890,6 @@ class JavaTest {
}
builder.endVector("floats", vecPos, true, false);
vecPos = builder.startVector();
for (final String i : strings) {
builder.putString(i);
}
builder.endVector("strings", vecPos, true, false);
vecPos = builder.startVector();
for (final boolean i : booleans) {
builder.putBoolean(i);
@@ -832,7 +903,6 @@ class JavaTest {
FlexBuffers.Reference r = FlexBuffers.getRoot(b);
assert(r.asMap().get("ints").isTypedVector());
assert(r.asMap().get("floats").isTypedVector());
assert(r.asMap().get("strings").isTypedVector());
assert(r.asMap().get("booleans").isTypedVector());
}
@@ -944,7 +1014,8 @@ class JavaTest {
testSingleElementLong();
testSingleElementFloat();
testSingleElementDouble();
testSingleElementString();
testSingleElementSmallString();
testSingleElementBigString();
testSingleElementBlob();
testSingleElementVector();
testSingleFixedTypeVector();
@@ -955,6 +1026,8 @@ class JavaTest {
testFlexBuffersTest();
testHashMapToMap();
testFlexBuferEmpty();
testFlexBufferVectorStrings();
testDeprecatedTypedVectorString();
}
static void TestVectorOfBytes() {