DoxigAlpha
std › fs › Dir › copyFile

copyFile

Atomically creates a new file at dest_path within dest_dir with the same contents as source_path within source_dir, overwriting any already existing file.

On Linux, until https://patchwork.kernel.org/patch/9636735/ is merged and readily available, there is a possibility of power loss or application termination leaving temporary files present in the same directory as dest_path.

On Windows, both paths should be encoded as WTF-8. On WASI, both paths should be encoded as valid UTF-8. On other platforms, both paths are an opaque sequence of bytes with no particular encoding.

Function parameters

Parameters

#
source_path:[]const u8
dest_path:[]const u8

Type definitions in this namespace

Types

#
SymLinkFlags
Use with `Dir.symLink`, `Dir.atomicSymLink`, and `symLinkAbsolute` to

Functions in this namespace

Functions

#
iterateAssumeFirstIteration
Like `iterate`, but will not reset the directory cursor before the first
walk
Recursively iterates over a directory.
openFile
Opens a file for reading or writing, without attempting to create a new file.
openFileZ
Same as `openFile` but the path parameter is null-terminated.
openFileW
Same as `openFile` but Windows-only and the path parameter is
createFile
Creates, opens, or overwrites a file with write access.
createFileZ
Same as `createFile` but the path parameter is null-terminated.
createFileW
Same as `createFile` but Windows-only and the path parameter is
makeDir
Creates a single directory with a relative or absolute path.
makeDirZ
Same as `makeDir`, but `sub_path` is null-terminated.
makeDirW
Creates a single directory with a relative or absolute null-terminated WTF-16 LE-encoded path.
makePath
Calls makeDir iteratively to make an entire path
makePathStatus
Same as `makePath` except returns whether the path already existed or was successfully created.
makeOpenPath
This function performs `makePath`, followed by `openDir`.
realpath
This function returns the canonicalized absolute pathname of
realpathZ
Same as `Dir.realpath` except `pathname` is null-terminated.
realpathW
Windows-only.
realpathAlloc
Same as `Dir.realpath` except caller must free the returned memory.
setAsCwd
Changes the current working directory to the open directory handle.
openDir
Opens a directory at the given path.
openDirZ
Same as `openDir` except the parameter is null-terminated.
openDirW
Same as `openDir` except the path parameter is WTF-16 LE encoded, NT-prefixed.
deleteFile
Delete a file name and possibly the file it refers to, based on an open directory handle.
deleteFileZ
Same as `deleteFile` except the parameter is null-terminated.
deleteFileW
Same as `deleteFile` except the parameter is WTF-16 LE encoded.
deleteDir
Returns `error.DirNotEmpty` if the directory is not empty.
deleteDirZ
Same as `deleteDir` except the parameter is null-terminated.
deleteDirW
Same as `deleteDir` except the parameter is WTF16LE, NT prefixed.
rename
Change the name or location of a file or directory.
renameZ
Same as `rename` except the parameters are null-terminated.
renameW
Same as `rename` except the parameters are WTF16LE, NT prefixed.
symLink
Creates a symbolic link named `sym_link_path` which contains the string `target_path`.
symLinkWasi
WASI-only.
symLinkZ
Same as `symLink`, except the pathname parameters are null-terminated.
symLinkW
Windows-only.
atomicSymLink
Same as `symLink`, except tries to create the symbolic link until it
readLink
Read value of a symbolic link.
readLinkWasi
WASI-only.
readLinkZ
Same as `readLink`, except the `sub_path_c` parameter is null-terminated.
readLinkW
Windows-only.
readFile
Read all of file contents using a preallocated buffer.
readFileAlloc
On success, caller owns returned buffer.
readFileAllocOptions
On success, caller owns returned buffer.
deleteTree
Whether `sub_path` describes a symlink, file, or directory, this function
deleteTreeMinStackSize
Like `deleteTree`, but only keeps one `Iterator` active at a time to minimize the function's stack size.
writeFile
Writes content to the file system, using the file creation flags provided.
access
Test accessing `sub_path`.
accessZ
Same as `access` except the path parameter is null-terminated.
accessW
Same as `access` except asserts the target OS is Windows and the path parameter is
updateFile
Check the file size, mtime, and mode of `source_path` and `dest_path`.
copyFile
Atomically creates a new file at `dest_path` within `dest_dir` with the
atomicFile
Directly access the `.file` field, and then call `AtomicFile.finish` to
statFile
Returns metadata for a file inside the directory.
chmod
Changes the mode of the directory.
chown
Changes the owner and group of the directory.
setPermissions
Sets permissions according to the provided `Permissions` struct.

Error sets in this namespace

Error Sets

#

= posix.fd_t

Values

#
Handle
= posix.fd_t

Source

Implementation

#
pub fn copyFile(
    source_dir: Dir,
    source_path: []const u8,
    dest_dir: Dir,
    dest_path: []const u8,
    options: CopyFileOptions,
) CopyFileError!void {
    var file_reader: File.Reader = .init(try source_dir.openFile(source_path, .{}), &.{});
    defer file_reader.file.close();

    const mode = options.override_mode orelse blk: {
        const st = try file_reader.file.stat();
        file_reader.size = st.size;
        break :blk st.mode;
    };

    var buffer: [1024]u8 = undefined; // Used only when direct fd-to-fd is not available.
    var atomic_file = try dest_dir.atomicFile(dest_path, .{
        .mode = mode,
        .write_buffer = &buffer,
    });
    defer atomic_file.deinit();

    _ = atomic_file.file_writer.interface.sendFileAll(&file_reader, .unlimited) catch |err| switch (err) {
        error.ReadFailed => return file_reader.err.?,
        error.WriteFailed => return atomic_file.file_writer.err.?,
    };

    try atomic_file.finish();
}