public void testInvalidTag() throws Exception {
// Any tag number which corresponds to field number zero is invalid and
// should throw InvalidProtocolBufferException.
for (int i = 0; i < 8; i++) {
try {
CodedInputStream.newInstance(bytes(i)).readTag();
fail("Should have thrown an exception.");
} catch (InvalidProtocolBufferException e) {
assertEquals(InvalidProtocolBufferException.invalidTag().getMessage(), e.getMessage());
}
}
}
/**
* Attempt to read a field tag, returning zero if we have reached EOF. Protocol message parsers
* use this to read tags, since a protocol message may legally end wherever a tag occurs, and zero
* is not a valid tag number.
*/
public int readTag() throws IOException {
if (isAtEnd()) {
lastTag = 0;
return 0;
}
lastTag = readRawVarint32();
if (WireFormat.getTagFieldNumber(lastTag) == 0) {
// If we actually read zero (or any tag number corresponding to field
// number zero), that's not a valid tag.
throw InvalidProtocolBufferException.invalidTag();
}
return lastTag;
}