1.Gen JSON crash when the field not filled; 2. not print when the field value is 0, see #209

[loachfish]

the commit-ecf5a6a does not solve the situation thar when the field value is 0.

My problem is that, I just modify the FILE:idl_gen_text.cppfunction; FUNCTION:GenStruct() LINE: if (struct_def.fixed || table->CheckField(fd.value.offset)) { to if (struct_def.fixed || table->CheckField(fd.value.offset) || true) { to ensure the value will be printed, while in this case it crashed.

the version i am using is git clone in 2015/01/12.

// test case, it can also test for #209 /Screen.fbs/ namespace hw.Screen;

enum LayOutType:ubyte { Full = 0, MasterSlave = 1 }

enum LayOutID:ubyte { MasterOrFullScreen = 0, Slave = 1 }

enum CursorCtrlType:ubyte { AddressingMode = 0, DestinationMode = 1 }

table NDBtnInfo { ID:ubyte; zoneID:ubyte; focusType:ubyte; specialBit:ubyte; x:ushort; y:ushort; w:ushort; h:ushort; upperBtnID:ubyte; lowerBtnID:ubyte; leftBtnID:ubyte; rightBtnID:ubyte; }

table NDTouchCoordinate{ layoutPattern:LayOutType; layoutID:LayOutID; overwriteFlag:bool; cursorControlType:CursorCtrlType;

btnCount:ubyte; 
btnInfo:[NDBtnInfo];

}

/_UTScreen.cpp/

include

include

include <sys/types.h>

include <sys/stat.h>

include

include

include

include

include "flatbuffers/flatbuffers.h"

include "flatbuffers/idl.h"

include "flatbuffers/util.h"

include "Screen_generated.h"

using namespace std; using namespace hw::Screen; using namespace flatbuffers;

ifndef NDEBUG

define NDEBUG

endif

int main(int argc, char* agrv[]) { std::vector orignal; orignal.push_back(0x00); orignal.push_back(0x01); orignal.push_back(0x00); orignal.push_back(0x01); orignal.push_back(0x00); orignal.push_back(0x00); orignal.push_back(0x00); orignal.push_back(0x00);

flatbuffers::FlatBufferBuilder fbb;
int index = 0;
unsigned char layoutPattern = orignal[index++];
unsigned char layoutID = orignal[index++];
unsigned char overwriteFlag = orignal[index++];
unsigned char cursorControlType = orignal[index++];
unsigned char btnCount = orignal[index++];
index += 3;

std::vector<flatbuffers::Offset<NDBtnInfo>> btnInfoList;
for (uint32_t i = 0; i < btnCount; ++i) {
    // as the btncnt is 0, do nothing;
}
NDTouchCoordinateBuilder mb(fbb);
mb.add_layoutPattern((LayOutType)layoutPattern);
mb.add_layoutID((LayOutID)layoutID);
mb.add_overwriteFlag(overwriteFlag);
mb.add_cursorControlType((CursorCtrlType)cursorControlType);
mb.add_btnCount(btnCount);

if (btnCount > 0) {
    // do nothing
    mb.add_btnInfo(fbb.CreateVector(btnInfoList));
}

fbb.Finish(mb.Finish());
//  fill flatbuffer's data to std::string
std::string fbs_str;
fbs_str.append((char*)fbb.GetBufferPointer(), fbb.GetSize());
printf("fbs str size[%d]\n", fbs_str.size());
for (int j = 0; j < fbs_str.size(); j++) {
    if ((j != 0) && (j % 8 == 0)) {
        printf("\n");
    }
    printf("0x%02x\t", fbs_str[j]);
}
printf("\n");

std::string filename("Screen.fbs");

// 1. load schemafile
std::string schemafile;
bool ok = flatbuffers::LoadFile(filename.c_str(), false, &schemafile);
if (!ok) {
    printf("couldn't load file.\n");
    return -1;
}

// 2. parse schema first, so we can use it to parse the data after
flatbuffers::Parser parser;
const char *include_directories[] = { nullptr, nullptr };
ok = parser.Parse(schemafile.c_str(), include_directories);
if (!ok) {
    printf("parse schema failed.\n");
    return -1;
}

// 3. set root table
std::string table("NDTouchCoordinate");
parser.SetRootType(table.c_str());

// 4. generate json string
// flatbuffers::GeneratorOptions()
flatbuffers::GeneratorOptions opts;
// opts.strict_json = true;

printf("+++++ GenerateText +++++\n");
std::string jsongen;
GenerateText(parser, fbs_str.c_str(), opts, &jsongen);

printf("json gen size[%d]:\n", jsongen.size());
printf("%s\n", jsongen.c_str());

return 0;

}

crash as signal 11 when gen struct about btnCount.

[loachfish]

maybe it was caused as that not fill the field btnInfo.

So the case is that when the vector is not filled, it will crash to gen?

[loachfish]

the function // Specialization of Print above for pointer types. template<> void Print<const void >(const void val, Type type, int indent, StructDef union_sd, const GeneratorOptions &opts, std::string _text); the val maybe nullptr, when the vector is not filled. when goto the function PrintVector, the pointer is nullptr.

So it add the condition: in the begine of function of Print if (val == nullptr) { return; }

it runs OK, but the output is like this: { layoutPattern: MasterSlave, layoutID: Slave, overwriteFlag: 1, cursorControlType: DestinationMode, btnCount: 0, btnInfo: }

[loachfish]

maybe we should fill the meta text when the val == nullptr, to ensure the format.

[aardappel]

are you using --defaults-json ? You adding || true does something similar to my commit, except it doesn't check that the field is scalar, which doesn't surprise me that it would crash.

[loachfish]

it works when add the options. flatbuffers::GeneratorOptions opts; opts.strict_json = true; opts.output_default_scalars_in_json = true; // key GenerateText(parser, fbs_str.c_str(), opts, &jsongen);

another syntax error when make in my env: flatbuffers/src/flathash.cpp:26:17: the enum items cannot end with a comma: enum OutputFormat { kDecimal, kHexadecimal, kHexadecimal0x, ///< };

Maybe it works well in some env, but it will affects the portability .

[ghost]

What compiler do you use, and what version?

[loachfish]

g++ (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3

Ubuntu 12.04

[ghost]

fixed that issue: https://github.com/google/flatbuffers/commit/12ca3e054e257e06e2c6e35e8824d5ae569bce4b