diff options
Diffstat (limited to 'third_party/rust/remove_dir_all/src/fs.rs')
| -rw-r--r-- | third_party/rust/remove_dir_all/src/fs.rs | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/third_party/rust/remove_dir_all/src/fs.rs b/third_party/rust/remove_dir_all/src/fs.rs new file mode 100644 index 0000000000..d81bd6563c --- /dev/null +++ b/third_party/rust/remove_dir_all/src/fs.rs @@ -0,0 +1,278 @@ +use std::ffi::OsString;
+use std::fs::{self, File, OpenOptions};
+use std::os::windows::prelude::*;
+use std::path::{Path, PathBuf};
+use std::{io, ptr};
+
+use winapi::shared::minwindef::*;
+use winapi::shared::winerror::*;
+use winapi::um::errhandlingapi::*;
+use winapi::um::fileapi::*;
+use winapi::um::minwinbase::*;
+use winapi::um::winbase::*;
+use winapi::um::winnt::*;
+
+pub const VOLUME_NAME_DOS: DWORD = 0x0;
+
+struct RmdirContext<'a> {
+ base_dir: &'a Path,
+ readonly: bool,
+ counter: u64,
+}
+
+/// Reliably removes a directory and all of its children.
+///
+/// ```rust
+/// extern crate remove_dir_all;
+///
+/// use std::fs;
+/// use remove_dir_all::*;
+///
+/// fn main() {
+/// fs::create_dir("./temp/").unwrap();
+/// remove_dir_all("./temp/").unwrap();
+/// }
+/// ```
+pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
+ // On Windows it is not enough to just recursively remove the contents of a
+ // directory and then the directory itself. Deleting does not happen
+ // instantaneously, but is scheduled.
+ // To work around this, we move the file or directory to some `base_dir`
+ // right before deletion to avoid races.
+ //
+ // As `base_dir` we choose the parent dir of the directory we want to
+ // remove. We very probably have permission to create files here, as we
+ // already need write permission in this dir to delete the directory. And it
+ // should be on the same volume.
+ //
+ // To handle files with names like `CON` and `morse .. .`, and when a
+ // directory structure is so deep it needs long path names the path is first
+ // converted to a `//?/`-path with `get_path()`.
+ //
+ // To make sure we don't leave a moved file laying around if the process
+ // crashes before we can delete the file, we do all operations on an file
+ // handle. By opening a file with `FILE_FLAG_DELETE_ON_CLOSE` Windows will
+ // always delete the file when the handle closes.
+ //
+ // All files are renamed to be in the `base_dir`, and have their name
+ // changed to "rm-<counter>". After every rename the counter is increased.
+ // Rename should not overwrite possibly existing files in the base dir. So
+ // if it fails with `AlreadyExists`, we just increase the counter and try
+ // again.
+ //
+ // For read-only files and directories we first have to remove the read-only
+ // attribute before we can move or delete them. This also removes the
+ // attribute from possible hardlinks to the file, so just before closing we
+ // restore the read-only attribute.
+ //
+ // If 'path' points to a directory symlink or junction we should not
+ // recursively remove the target of the link, but only the link itself.
+ //
+ // Moving and deleting is guaranteed to succeed if we are able to open the
+ // file with `DELETE` permission. If others have the file open we only have
+ // `DELETE` permission if they have specified `FILE_SHARE_DELETE`. We can
+ // also delete the file now, but it will not disappear until all others have
+ // closed the file. But no-one can open the file after we have flagged it
+ // for deletion.
+
+ // Open the path once to get the canonical path, file type and attributes.
+ let (path, metadata) = {
+ let path = path.as_ref();
+ let mut opts = OpenOptions::new();
+ opts.access_mode(FILE_READ_ATTRIBUTES);
+ opts.custom_flags(FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT);
+ let file = opts.open(path)?;
+ (get_path(&file)?, path.metadata()?)
+ };
+
+ let mut ctx = RmdirContext {
+ base_dir: match path.parent() {
+ Some(dir) => dir,
+ None => {
+ return Err(io::Error::new(
+ io::ErrorKind::PermissionDenied,
+ "Can't delete root directory",
+ ))
+ }
+ },
+ readonly: metadata.permissions().readonly(),
+ counter: 0,
+ };
+
+ let filetype = metadata.file_type();
+ if filetype.is_dir() {
+ if !filetype.is_symlink() {
+ remove_dir_all_recursive(path.as_ref(), &mut ctx)
+ } else {
+ remove_item(path.as_ref(), &mut ctx)
+ }
+ } else {
+ Err(io::Error::new(
+ io::ErrorKind::PermissionDenied,
+ "Not a directory",
+ ))
+ }
+}
+
+fn remove_item(path: &Path, ctx: &mut RmdirContext) -> io::Result<()> {
+ if ctx.readonly {
+ // remove read-only permision
+ let mut permissions = path.metadata()?.permissions();
+ permissions.set_readonly(false);
+
+ fs::set_permissions(path, permissions)?;
+ }
+
+ let mut opts = OpenOptions::new();
+ opts.access_mode(DELETE);
+ opts.custom_flags(
+ FILE_FLAG_BACKUP_SEMANTICS | // delete directory
+ FILE_FLAG_OPEN_REPARSE_POINT | // delete symlink
+ FILE_FLAG_DELETE_ON_CLOSE,
+ );
+ let file = opts.open(path)?;
+ move_item(&file, ctx)?;
+
+ if ctx.readonly {
+ // restore read-only flag just in case there are other hard links
+ match fs::metadata(&path) {
+ Ok(metadata) => {
+ let mut perm = metadata.permissions();
+ perm.set_readonly(true);
+ fs::set_permissions(&path, perm)?;
+ }
+ Err(ref err) if err.kind() == io::ErrorKind::NotFound => {}
+ err => return err.map(|_| ()),
+ }
+ }
+
+ Ok(())
+}
+
+fn move_item(file: &File, ctx: &mut RmdirContext) -> io::Result<()> {
+ let mut tmpname = ctx.base_dir.join(format! {"rm-{}", ctx.counter});
+ ctx.counter += 1;
+
+ // Try to rename the file. If it already exists, just retry with an other
+ // filename.
+ while let Err(err) = rename(file, &tmpname, false) {
+ if err.kind() != io::ErrorKind::AlreadyExists {
+ return Err(err);
+ };
+ tmpname = ctx.base_dir.join(format!("rm-{}", ctx.counter));
+ ctx.counter += 1;
+ }
+
+ Ok(())
+}
+
+fn rename(file: &File, new: &Path, replace: bool) -> io::Result<()> {
+ // &self must be opened with DELETE permission
+ use std::iter;
+ #[cfg(target_pointer_width = "32")]
+ const STRUCT_SIZE: usize = 12;
+ #[cfg(target_pointer_width = "64")]
+ const STRUCT_SIZE: usize = 20;
+
+ // FIXME: check for internal NULs in 'new'
+ let mut data: Vec<u16> = iter::repeat(0u16)
+ .take(STRUCT_SIZE / 2)
+ .chain(new.as_os_str().encode_wide())
+ .collect();
+ data.push(0);
+ let size = data.len() * 2;
+
+ unsafe {
+ // Thanks to alignment guarantees on Windows this works
+ // (8 for 32-bit and 16 for 64-bit)
+ let info = data.as_mut_ptr() as *mut FILE_RENAME_INFO;
+ // The type of ReplaceIfExists is BOOL, but it actually expects a
+ // BOOLEAN. This means true is -1, not c::TRUE.
+ (*info).ReplaceIfExists = if replace { -1 } else { FALSE };
+ (*info).RootDirectory = ptr::null_mut();
+ (*info).FileNameLength = (size - STRUCT_SIZE) as DWORD;
+ let result = SetFileInformationByHandle(
+ file.as_raw_handle(),
+ FileRenameInfo,
+ data.as_mut_ptr() as *mut _ as *mut _,
+ size as DWORD,
+ );
+
+ if result == 0 {
+ Err(io::Error::last_os_error())
+ } else {
+ Ok(())
+ }
+ }
+}
+
+fn get_path(f: &File) -> io::Result<PathBuf> {
+ fill_utf16_buf(
+ |buf, sz| unsafe { GetFinalPathNameByHandleW(f.as_raw_handle(), buf, sz, VOLUME_NAME_DOS) },
+ |buf| PathBuf::from(OsString::from_wide(buf)),
+ )
+}
+
+fn remove_dir_all_recursive(path: &Path, ctx: &mut RmdirContext) -> io::Result<()> {
+ let dir_readonly = ctx.readonly;
+ for child in fs::read_dir(path)? {
+ let child = child?;
+ let child_type = child.file_type()?;
+ ctx.readonly = child.metadata()?.permissions().readonly();
+ if child_type.is_dir() {
+ remove_dir_all_recursive(&child.path(), ctx)?;
+ } else {
+ remove_item(&child.path().as_ref(), ctx)?;
+ }
+ }
+ ctx.readonly = dir_readonly;
+ remove_item(path, ctx)
+}
+
+fn fill_utf16_buf<F1, F2, T>(mut f1: F1, f2: F2) -> io::Result<T>
+where
+ F1: FnMut(*mut u16, DWORD) -> DWORD,
+ F2: FnOnce(&[u16]) -> T,
+{
+ // Start off with a stack buf but then spill over to the heap if we end up
+ // needing more space.
+ let mut stack_buf = [0u16; 512];
+ let mut heap_buf = Vec::new();
+ unsafe {
+ let mut n = stack_buf.len();
+
+ loop {
+ let buf = if n <= stack_buf.len() {
+ &mut stack_buf[..]
+ } else {
+ let extra = n - heap_buf.len();
+ heap_buf.reserve(extra);
+ heap_buf.set_len(n);
+ &mut heap_buf[..]
+ };
+
+ // This function is typically called on windows API functions which
+ // will return the correct length of the string, but these functions
+ // also return the `0` on error. In some cases, however, the
+ // returned "correct length" may actually be 0!
+ //
+ // To handle this case we call `SetLastError` to reset it to 0 and
+ // then check it again if we get the "0 error value". If the "last
+ // error" is still 0 then we interpret it as a 0 length buffer and
+ // not an actual error.
+ SetLastError(0);
+ let k = match f1(buf.as_mut_ptr(), n as DWORD) {
+ 0 if GetLastError() == 0 => 0,
+ 0 => return Err(io::Error::last_os_error()),
+ n => n,
+ } as usize;
+ if k == n && GetLastError() == ERROR_INSUFFICIENT_BUFFER {
+ n *= 2;
+ } else if k >= n {
+ n = k;
+ } else {
+ return Ok(f2(&buf[..k]));
+ }
+ }
+ }
+}
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