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/*
* Copyright 2018 Google
*
* 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.
*/
#include "Firestore/core/src/firebase/firestore/nanopb/reader.h"
#include "Firestore/Protos/nanopb/google/firestore/v1beta1/document.pb.h"
namespace firebase {
namespace firestore {
namespace nanopb {
using firebase::firestore::util::Status;
using std::int64_t;
using std::uint64_t;
Reader Reader::Wrap(const uint8_t* bytes, size_t length) {
return Reader{pb_istream_from_buffer(bytes, length)};
}
Tag Reader::ReadTag() {
Tag tag;
if (!status_.ok()) return tag;
bool eof;
if (!pb_decode_tag(&stream_, &tag.wire_type, &tag.field_number, &eof)) {
status_ = Status(FirestoreErrorCode::DataLoss, PB_GET_ERROR(&stream_));
return tag;
}
// nanopb code always returns a false status when setting eof.
FIREBASE_ASSERT_MESSAGE(!eof, "nanopb set both ok status and eof to true");
return tag;
}
void Reader::ReadNanopbMessage(const pb_field_t fields[], void* dest_struct) {
if (!status_.ok()) return;
if (!pb_decode(&stream_, fields, dest_struct)) {
status_ = Status(FirestoreErrorCode::DataLoss, PB_GET_ERROR(&stream_));
}
}
/**
* Note that (despite the return type) this works for bool, enum, int32, int64,
* uint32 and uint64 proto field types.
*
* Note: This is not expected to be called directly, but rather only via the
* other Decode* methods (i.e. DecodeBool, DecodeLong, etc)
*
* @return The decoded varint as a uint64_t.
*/
uint64_t Reader::ReadVarint() {
if (!status_.ok()) return 0;
uint64_t varint_value = 0;
if (!pb_decode_varint(&stream_, &varint_value)) {
status_ = Status(FirestoreErrorCode::DataLoss, PB_GET_ERROR(&stream_));
}
return varint_value;
}
void Reader::ReadNull() {
uint64_t varint = ReadVarint();
if (!status_.ok()) return;
if (varint != google_protobuf_NullValue_NULL_VALUE) {
status_ = Status(FirestoreErrorCode::DataLoss,
"Input proto bytes cannot be parsed (invalid null value)");
}
}
bool Reader::ReadBool() {
uint64_t varint = ReadVarint();
if (!status_.ok()) return false;
switch (varint) {
case 0:
return false;
case 1:
return true;
default:
status_ =
Status(FirestoreErrorCode::DataLoss,
"Input proto bytes cannot be parsed (invalid bool value)");
return false;
}
}
int64_t Reader::ReadInteger() {
return ReadVarint();
}
std::string Reader::ReadString() {
if (!status_.ok()) return "";
pb_istream_t substream;
if (!pb_make_string_substream(&stream_, &substream)) {
status_ = Status(FirestoreErrorCode::DataLoss, PB_GET_ERROR(&stream_));
pb_close_string_substream(&stream_, &substream);
return "";
}
std::string result(substream.bytes_left, '\0');
if (!pb_read(&substream, reinterpret_cast<pb_byte_t*>(&result[0]),
substream.bytes_left)) {
status_ = Status(FirestoreErrorCode::DataLoss, PB_GET_ERROR(&stream_));
pb_close_string_substream(&stream_, &substream);
return "";
}
// NB: future versions of nanopb read the remaining characters out of the
// substream (and return false if that fails) as an additional safety
// check within pb_close_string_substream. Unfortunately, that's not present
// in the current version (0.38). We'll make a stronger assertion and check
// to make sure there *are* no remaining characters in the substream.
FIREBASE_ASSERT_MESSAGE(
substream.bytes_left == 0,
"Bytes remaining in substream after supposedly reading all of them.");
pb_close_string_substream(&stream_, &substream);
return result;
}
} // namespace nanopb
} // namespace firestore
} // namespace firebase
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