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Add a posix-native copy_file.
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This PR is part of the std::filesystem removal-on-POSIX project.
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@BillyONeal
BillyONeal committed Sep 29, 2021
1 parent 61d982d commit 13d5427
Showing 1 changed file with 145 additions and 51 deletions.
196 changes: 145 additions & 51 deletions src/vcpkg/base/files.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2070,67 +2070,24 @@ namespace vcpkg
#if !defined(_WIN32)
if (ec)
{
auto dst = new_path;
dst += temp_suffix;

PosixFd i_fd{old_path.c_str(), O_RDONLY, ec};
if (ec) return;

PosixFd o_fd{dst.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0664, ec};
if (ec) return;

#if defined(__linux__)
off_t bytes = 0;
struct stat info = {0};
i_fd.fstat(&info, ec);
if (ec) return;
auto written_bytes = sendfile(o_fd.get(), i_fd.get(), &bytes, info.st_size);
#elif defined(__APPLE__)
auto written_bytes = fcopyfile(i_fd.get(), o_fd.get(), 0, COPYFILE_ALL);
#else // ^^^ defined(__APPLE__) // !(defined(__APPLE__) || defined(__linux__)) vvv
ssize_t written_bytes = 0;
auto dst = new_path + temp_suffix;
this->copy_file(old_path, dst, CopyOptions::overwrite_existing, ec);
if (ec)
{
constexpr std::size_t buffer_length = 4096;
unsigned char buffer[buffer_length];
while (auto read_bytes = i_fd.read(buffer, buffer_length))
{
if (read_bytes == -1)
{
written_bytes = -1;
break;
}
auto remaining = read_bytes;
while (remaining > 0)
{
auto read_result = o_fd.write(buffer, remaining);
if (read_result == -1)
{
written_bytes = -1;
// break two loops
goto copy_failure;
}
remaining -= read_result;
}
}

copy_failure:;
return;
}
#endif // ^^^ !(defined(__APPLE__) || defined(__linux__))
if (written_bytes == -1)

this->rename(dst, new_path, ec);
if (ec)
{
ec.assign(errno, std::generic_category());
return;
}

i_fd.close();
o_fd.close();

this->rename(dst, new_path, ec);
if (ec) return;
this->remove(old_path, ec);
}
#endif // ^^^ !defined(_WIN32)
}

virtual bool remove(const Path& target, std::error_code& ec) override
{
auto as_stdfs = to_stdfs_path(target);
Expand Down Expand Up @@ -2250,9 +2207,146 @@ namespace vcpkg
CopyOptions options,
std::error_code& ec) override
{
#if defined(_WIN32)
return stdfs::copy_file(
to_stdfs_path(source), to_stdfs_path(destination), convert_copy_options(options), ec);
#else // ^^^ _WIN32 // !_WIN32 vvv
PosixFd source_fd{source.c_str(), O_RDONLY, ec};
if (ec)
{
return false;
}

struct stat source_stat;
source_fd.fstat(&source_stat, ec);
if (ec)
{
return false;
}

if (!S_ISREG(source_stat.st_mode))
{
// N4861 [fs.op.copy.file]/4: "report an error if"
// is_regular_file(from) is false
ec = std::make_error_code(std::errc::invalid_argument);
return false;
}

bool destination_exists;
struct stat destination_stat;
if (lstat(destination.c_str(), &destination_stat) == 0)
{
if (!S_ISREG(destination_stat.st_mode))
{
// /4 exists(to) and is_regular_file(to) is false
ec = std::make_error_code(std::errc::invalid_argument);
return false;
}

destination_exists = true;
}
else if (errno == ENOENT)
{
destination_exists = false;
}
else
{
ec.assign(errno, std::generic_category());
return false;
}

if (destination_exists && source_stat.st_dev == destination_stat.st_dev &&
source_stat.st_ino == destination_stat.st_ino)
{
// /4 exists(to) i s true and equivalent(from, to) is true
ec = std::make_error_code(std::errc::device_or_resource_busy);
return false;
}

auto masked_options =
static_cast<CopyOptions>(static_cast<int>(options) & static_cast<int>(CopyOptions::existing_mask));
if (destination_exists && masked_options == CopyOptions::none)
{
// /4 exists(to) is true and
// (options & (copy_options::skip_existing |
// copy_options::overwrite_existing |
// copy_options::update_existing)) == copy_options::none
ec = std::make_error_code(std::errc::file_exists);
return false;
}

// /4: "Otherwise, copies the contents and attributes of the file from resolves to, to the file to resolves
// to, if
// * exists(to) is false
// * (options & copy_options::overwrite_existing) != copy_options::none
// * (options & copy_options::update_existing) != copy_options::none"
// Note that we don't implement update_existing.
if (destination_exists && masked_options == CopyOptions::skip_existing)
{
// /4 "Otherwise, no effects."
ec.clear();
return false;
}

Checks::check_exit(VCPKG_LINE_INFO,
!destination_exists || masked_options == CopyOptions::overwrite_existing);

PosixFd destination_fd{destination.c_str(),
O_WRONLY | O_CREAT | O_TRUNC,
static_cast<mode_t>(source_stat.st_mode & 0777u),
ec};
if (ec)
{
return false;
}

#if defined(__linux__)
off_t bytes = 0;
if (sendfile(destination_fd.get(), source_fd.get(), &bytes, source_stat.st_size) == -1)
{
ec.assign(errno, std::generic_category());
return false;
}

return true;
#elif defined(__APPLE__)
if (fcopyfile(source_fd.get(), destination_fd.get(), 0, COPYFILE_ALL) == -1)
{
ec.assign(errno, std::generic_category());
return false;
}

return true;
#else // ^^^ defined(__APPLE__) // !(defined(__APPLE__) || defined(__linux__)) vvv
constexpr std::size_t buffer_length = 4096;
unsigned char buffer[buffer_length];
while (auto read_bytes = i_fd.read(buffer, buffer_length))
{
if (read_bytes == -1)
{
ec.assign(errno, std::generic_category());
return false;
}

auto remaining = read_bytes;
while (remaining > 0)
{
auto write_result = destination_fd.write(buffer, remaining);
if (write_result == -1)
{
ec.assign(errno, std::generic_category());
return false;
}

remaining -= write_result;
}
}

return true;
#endif // ^^^ !(defined(__APPLE__) || defined(__linux__))
#endif // ^^^ !_WIN32
}

virtual void copy_symlink(const Path& source, const Path& destination, std::error_code& ec) override
{
return stdfs::copy_symlink(to_stdfs_path(source), to_stdfs_path(destination), ec);
Expand Down

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