jiuyiUniapp/service/node_modules/react-native/ReactCommon/cxxreact/JSBigString.cpp

118 lines
3.2 KiB
C++

/*
* 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.
*/
#include "JSBigString.h"
#include <glog/logging.h>
#include <folly/Memory.h>
#include <folly/portability/Fcntl.h>
#include <folly/portability/SysMman.h>
#include <folly/portability/SysStat.h>
#include <folly/portability/Unistd.h>
#include <memory>
namespace facebook::react {
JSBigFileString::JSBigFileString(int fd, size_t size, off_t offset /*= 0*/)
: m_fd{-1}, m_data{nullptr} {
m_fd = dup(fd);
if (m_fd == -1) {
const char* message =
"JSBigFileString::JSBigFileString - Could not duplicate file descriptor";
LOG(ERROR) << message;
throw std::runtime_error(message);
}
// Offsets given to mmap must be page aligned. We abstract away that
// restriction by sending a page aligned offset to mmap, and keeping track
// of the offset within the page that we must alter the mmap pointer by to
// get the final desired offset.
if (offset != 0) {
const static auto ps = sysconf(_SC_PAGESIZE);
auto d = lldiv(offset, ps);
m_mapOff = static_cast<off_t>(d.quot);
m_pageOff = static_cast<off_t>(d.rem);
m_size = size + m_pageOff;
} else {
m_mapOff = 0;
m_pageOff = 0;
m_size = size;
}
}
JSBigFileString::~JSBigFileString() {
if (m_data) {
munmap((void*)m_data, m_size);
}
folly::fileops::close(m_fd);
}
const char* JSBigFileString::c_str() const {
if (m_size == 0) {
return "";
}
if (!m_data) {
m_data =
(const char*)mmap(0, m_size, PROT_READ, MAP_PRIVATE, m_fd, m_mapOff);
CHECK(m_data != MAP_FAILED)
<< " fd: " << m_fd << " size: " << m_size << " offset: " << m_mapOff
<< " error: " << std::strerror(errno);
}
static const size_t kMinPageSize = 4096;
CHECK(!(reinterpret_cast<uintptr_t>(m_data) & (kMinPageSize - 1)))
<< "mmap address misaligned, likely corrupted"
<< " m_data: " << (const void*)m_data;
CHECK(m_pageOff <= m_size)
<< "offset impossibly large, likely corrupted"
<< " m_pageOff: " << m_pageOff << " m_size: " << m_size;
return m_data + m_pageOff;
}
size_t JSBigFileString::size() const {
// Ensure mapping has been initialized.
c_str();
return m_size - m_pageOff;
}
int JSBigFileString::fd() const {
return m_fd;
}
std::unique_ptr<const JSBigFileString> JSBigFileString::fromPath(
const std::string& sourceURL) {
int fd = folly::fileops::open(sourceURL.c_str(), O_RDONLY);
if (fd == -1) {
const std::string message =
std::string("JSBigFileString::fromPath - Could not open file: ") +
sourceURL;
LOG(ERROR) << message;
throw std::runtime_error(message.c_str());
}
struct stat fileInfo {};
int res = ::fstat(fd, &fileInfo);
if (res == -1) {
const std::string message =
"JSBigFileString::fromPath - fstat on bundle failed: " + sourceURL;
LOG(ERROR) << message;
folly::fileops::close(fd);
throw std::runtime_error(message.c_str());
}
auto ptr = std::make_unique<const JSBigFileString>(fd, fileInfo.st_size);
CHECK(folly::fileops::close(fd) == 0);
return ptr;
}
} // namespace facebook::react