/*

* Copyright (c) Meta Platforms, Inc. and affiliates.

*

* This source code is licensed under the MIT license found in the

* LICENSE file in the root directory of this source tree.

*/

#ifndef _WINDOWS

#include <fcntl.h>

#include <sys/mman.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <unistd.h>

#include <cerrno>

#include <cstdarg>

#include <stdexcept>

#include "jsi/jsilib.h"

namespace facebook {

namespace jsi {

namespace {

constexpr size_t kErrorBufferSize = 512;

__attribute__((format(printf, 1, 2))) void throwFormattedError(const char* fmt,

...) {

char logBuffer[kErrorBufferSize];

va_list va_args;

va_start(va_args, fmt);

int result = vsnprintf(logBuffer, sizeof(logBuffer), fmt, va_args);

va_end(va_args);

if (result < 0) {

throw JSINativeException(std::string("Failed to format error message: ") +

fmt);

}

throw JSINativeException(logBuffer);

}

class ScopedFile {

public:

ScopedFile(const std::string& path)

: path_(path), fd_(::open(path.c_str(), O_RDONLY)) {

if (fd_ == -1) {

throwFormattedError("Could not open %s: %s", path.c_str(),

strerror(errno));

}

}

~ScopedFile() { ::close(fd_); }

size_t size() {

struct stat fileInfo;

if (::fstat(fd_, &fileInfo) == -1) {

throwFormattedError("Could not stat %s: %s", path_.c_str(),

strerror(errno));

}

return fileInfo.st_size;

}

uint8_t* mmap(size_t size) {

void* result = ::mmap(nullptr, size, PROT_READ, MAP_PRIVATE, fd_, 0);

if (result == MAP_FAILED) {

throwFormattedError("Could not mmap %s: %s", path_.c_str(),

strerror(errno));

}

return reinterpret_cast<uint8_t*>(result);

}

const std::string& path_;

const int fd_;

};

} // namespace

FileBuffer::FileBuffer(const std::string& path) {

ScopedFile file(path);

size_ = file.size();

data_ = file.mmap(size_);

}

FileBuffer::~FileBuffer() {

if (::munmap(data_, size_)) {

// terminate the program with pending exception

try {

throwFormattedError("Could not unmap memory (%p, %zu bytes): %s", data_,

size_, strerror(errno));

} catch (...) {

std::terminate();

}

}

}

} // namespace jsi

} // namespace facebook

#endif // !defined(_WINDOWS)