86 строки
2.1 KiB
C++
86 строки
2.1 KiB
C++
// Copyright (c) Facebook, Inc. and its 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 <fcntl.h>
|
|
#include <sys/stat.h>
|
|
|
|
#include <glog/logging.h>
|
|
|
|
#include <folly/Memory.h>
|
|
#include <folly/portability/SysMman.h>
|
|
#include <folly/ScopeGuard.h>
|
|
|
|
namespace facebook {
|
|
namespace react {
|
|
|
|
JSBigFileString::JSBigFileString(int fd, size_t size, off_t offset /*= 0*/)
|
|
: m_fd { -1 }
|
|
, m_data { nullptr } {
|
|
folly::checkUnixError(m_fd = dup(fd),
|
|
"Could not duplicate file descriptor");
|
|
|
|
// Offsets given to mmap must be page aligend. 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 = getpagesize();
|
|
auto d = lldiv(offset, ps);
|
|
|
|
m_mapOff = d.quot;
|
|
m_pageOff = 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);
|
|
}
|
|
close(m_fd);
|
|
}
|
|
|
|
|
|
const char *JSBigFileString::c_str() const {
|
|
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);
|
|
}
|
|
return m_data + m_pageOff;
|
|
}
|
|
|
|
size_t JSBigFileString::size() const {
|
|
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 = ::open(sourceURL.c_str(), O_RDONLY);
|
|
folly::checkUnixError(fd, "Could not open file", sourceURL);
|
|
SCOPE_EXIT { CHECK(::close(fd) == 0); };
|
|
|
|
struct stat fileInfo;
|
|
folly::checkUnixError(::fstat(fd, &fileInfo), "fstat on bundle failed.");
|
|
|
|
return folly::make_unique<const JSBigFileString>(fd, fileInfo.st_size);
|
|
}
|
|
|
|
} // namespace react
|
|
} // namespace facebook
|