// Copyright 2018 The Dawn Authors
//
// 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 <csetjmp>
#include <csignal>
#include <cstdint>
#include <string>
#include <vector>

#include "DawnSPIRVCrossFuzzer.h"

namespace {

    std::jmp_buf jump_buffer;
    void (*old_signal_handler)(int);

    // Handler to trap signals, so that it doesn't crash the fuzzer when running
    // the code under test. Currently the
    // code being fuzzed uses abort() to report errors like bad input instead of
    // returning an error code. This will be changing in the future.
    //
    // TODO(rharrison): Remove all of this signal trapping once SPIRV-Cross has
    // been changed to not use abort() for reporting errors.
    [[noreturn]] static void sigabrt_trap(int sig) {
        std::longjmp(jump_buffer, 1);
    }

    // Setup the SIGABRT trap
    void BeginSIGABRTTrap() {
        old_signal_handler = signal(SIGABRT, sigabrt_trap);
        if (old_signal_handler == SIG_ERR)
            abort();
    }

    // Restore the previous signal handler
    void EndSIGABRTTrap() {
        signal(SIGABRT, old_signal_handler);
    }

}  // namespace

namespace DawnSPIRVCrossFuzzer {

    int Run(const uint8_t* data, size_t size, std::function<int(std::vector<uint32_t>)> task) {
        if (!data || size < 1)
            return 0;

        std::vector<uint32_t> input(data, data + (4 * (size / 4)));

        BeginSIGABRTTrap();

        // On the first pass through setjmp will return 0, if returning here
        // from the longjmp in the signal handler it will return 1.
        if (setjmp(jump_buffer) == 0) {
            task(input);
        }

        EndSIGABRTTrap();

        return 0;
    }

    template <class Options>
    int RunWithOptions(const uint8_t* data,
                       size_t size,
                       std::function<int(std::vector<uint32_t>, Options)> task) {
        if (!data || size < sizeof(Options) + 1)
            return 0;

        Options options = *reinterpret_cast<const Options*>(data);
        data += sizeof(options);
        size -= sizeof(options);

        std::vector<uint32_t> input(data, data + (4 * (size / 4)));

        BeginSIGABRTTrap();

        // On the first pass through setjmp will return 0, if returning here
        // from the longjmp in the signal handler it will return 1.
        if (setjmp(jump_buffer) == 0) {
            task(input, options);
        }

        EndSIGABRTTrap();

        return 0;
    }

    template int RunWithOptions<spirv_cross::CompilerGLSL::Options>(
        const uint8_t*,
        size_t,
        TaskWithOptions<spirv_cross::CompilerGLSL::Options>);
    template int RunWithOptions<spirv_cross::CompilerHLSL::Options>(
        const uint8_t*,
        size_t,
        TaskWithOptions<spirv_cross::CompilerHLSL::Options>);
    template int RunWithOptions<CombinedOptions>(const uint8_t*,
                                                 size_t,
                                                 TaskWithOptions<CombinedOptions>);

}  // namespace DawnSPIRVCrossFuzzer