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/*
* Copyright (C) 2007-2025 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "FileHandle.h"
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <wtf/CheckedArithmetic.h>
#include <wtf/FileSystem.h>
#include <wtf/MallocSpan.h>
#include <wtf/MappedFileData.h>
namespace WTF::FileSystemImpl {
std::optional<uint64_t> FileHandle::read(std::span<uint8_t> data)
{
if (!m_handle)
return { };
do {
auto bytesRead = ::read(*m_handle, data.data(), data.size());
if (bytesRead >= 0)
return bytesRead;
} while (errno == EINTR);
return { };
}
std::optional<uint64_t> FileHandle::write(std::span<const uint8_t> data)
{
if (!m_handle)
return { };
do {
auto bytesWritten = ::write(*m_handle, data.data(), data.size());
if (bytesWritten >= 0)
return bytesWritten;
} while (errno == EINTR);
return { };
}
bool FileHandle::truncate(int64_t offset)
{
// ftruncate returns 0 to indicate the success.
return m_handle && !ftruncate(*m_handle, offset);
}
bool FileHandle::flush()
{
return m_handle && !fsync(*m_handle);
}
std::optional<uint64_t> FileHandle::seek(int64_t offset, FileSeekOrigin origin)
{
if (!m_handle)
return { };
int whence = SEEK_SET;
switch (origin) {
case FileSeekOrigin::Beginning:
whence = SEEK_SET;
break;
case FileSeekOrigin::Current:
whence = SEEK_CUR;
break;
case FileSeekOrigin::End:
whence = SEEK_END;
break;
default:
ASSERT_NOT_REACHED();
break;
}
auto result = lseek(*m_handle, offset, whence);
if (result < 0)
return { };
return static_cast<uint64_t>(result);
}
std::optional<PlatformFileID> FileHandle::id()
{
if (!m_handle)
return std::nullopt;
struct stat fileInfo;
if (fstat(*m_handle, &fileInfo))
return std::nullopt;
return fileInfo.st_ino;
}
void FileHandle::close()
{
if (auto handle = std::exchange(m_handle, std::nullopt))
::close(*handle);
}
std::optional<uint64_t> FileHandle::size()
{
if (!m_handle)
return std::nullopt;
struct stat fileInfo;
if (fstat(*m_handle, &fileInfo))
return std::nullopt;
return fileInfo.st_size;
}
#if USE(FILE_LOCK)
bool FileHandle::lock(OptionSet<FileLockMode> lockMode)
{
if (!m_handle)
return false;
static_assert(LOCK_SH == WTF::enumToUnderlyingType(FileLockMode::Shared), "LockSharedEncoding is as expected");
static_assert(LOCK_EX == WTF::enumToUnderlyingType(FileLockMode::Exclusive), "LockExclusiveEncoding is as expected");
static_assert(LOCK_NB == WTF::enumToUnderlyingType(FileLockMode::Nonblocking), "LockNonblockingEncoding is as expected");
return flock(*m_handle, lockMode.toRaw()) != -1;
}
#endif // USE(FILE_LOCK)
#if HAVE(MMAP)
std::optional<MappedFileData> FileHandle::map(MappedFileMode mapMode, FileOpenMode openMode)
{
if (!m_handle)
return { };
struct stat fileStat;
if (fstat(platformHandle(), &fileStat))
return { };
size_t size;
if (!WTF::convertSafely(fileStat.st_size, size))
return { };
if (!size)
return MappedFileData { };
int pageProtection = PROT_READ;
switch (openMode) {
case FileOpenMode::Read:
pageProtection = PROT_READ;
break;
case FileOpenMode::Truncate:
pageProtection = PROT_WRITE;
break;
case FileOpenMode::ReadWrite:
pageProtection = PROT_READ | PROT_WRITE;
break;
#if OS(DARWIN)
case FileOpenMode::EventsOnly:
ASSERT_NOT_REACHED();
#endif
}
auto fileData = MallocSpan<uint8_t, Mmap>::mmap(nullptr, size, pageProtection, MAP_FILE | (mapMode == MappedFileMode::Shared ? MAP_SHARED : MAP_PRIVATE), platformHandle());
if (!fileData)
return { };
return MappedFileData { WTFMove(fileData) };
}
#endif // HAVE(MMAP)
} // WTF::FileSystemImpl
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