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use crate::error::{Error, Result};
use crate::gen::fs;
use crate::paths;
use std::io;
use std::path::Path;
pub(crate) fn write(path: impl AsRef<Path>, content: &[u8]) -> Result<()> {
let path = path.as_ref();
let mut create_dir_error = None;
if fs::exists(path) {
if let Ok(existing) = fs::read(path) {
if existing == content {
// Avoid bumping modified time with unchanged contents.
return Ok(());
}
}
best_effort_remove(path);
} else {
let parent = path.parent().unwrap();
create_dir_error = fs::create_dir_all(parent).err();
}
match fs::write(path, content) {
// As long as write succeeded, ignore any create_dir_all error.
Ok(()) => Ok(()),
// If create_dir_all and write both failed, prefer the first error.
Err(err) => Err(Error::Fs(create_dir_error.unwrap_or(err))),
}
}
pub(crate) fn symlink_file(original: impl AsRef<Path>, link: impl AsRef<Path>) -> Result<()> {
let original = original.as_ref();
let link = link.as_ref();
let mut create_dir_error = None;
if fs::exists(link) {
best_effort_remove(link);
} else {
let parent = link.parent().unwrap();
create_dir_error = fs::create_dir_all(parent).err();
}
match paths::symlink_or_copy(original, link) {
// As long as symlink_or_copy succeeded, ignore any create_dir_all error.
Ok(()) => Ok(()),
Err(err) => {
if err.kind() == io::ErrorKind::AlreadyExists {
// This is fine, a different simultaneous build script already
// created the same link or copy. The cxx_build target directory
// is laid out such that the same path never refers to two
// different targets during the same multi-crate build, so if
// some other build script already created the same path then we
// know it refers to the identical target that the current build
// script was trying to create.
Ok(())
} else {
// If create_dir_all and symlink_or_copy both failed, prefer the
// first error.
Err(Error::Fs(create_dir_error.unwrap_or(err)))
}
}
}
}
pub(crate) fn symlink_dir(original: impl AsRef<Path>, link: impl AsRef<Path>) -> Result<()> {
let original = original.as_ref();
let link = link.as_ref();
let mut create_dir_error = None;
if fs::exists(link) {
best_effort_remove(link);
} else {
let parent = link.parent().unwrap();
create_dir_error = fs::create_dir_all(parent).err();
}
match fs::symlink_dir(original, link) {
// As long as symlink_dir succeeded, ignore any create_dir_all error.
Ok(()) => Ok(()),
// If create_dir_all and symlink_dir both failed, prefer the first error.
Err(err) => Err(Error::Fs(create_dir_error.unwrap_or(err))),
}
}
fn best_effort_remove(path: &Path) {
use std::fs;
if cfg!(windows) {
// On Windows, the correct choice of remove_file vs remove_dir needs to
// be used according to what the symlink *points to*. Trying to use
// remove_file to remove a symlink which points to a directory fails
// with "Access is denied".
if let Ok(metadata) = fs::metadata(path) {
if metadata.is_dir() {
let _ = fs::remove_dir_all(path);
} else {
let _ = fs::remove_file(path);
}
} else if fs::symlink_metadata(path).is_ok() {
// The symlink might exist but be dangling, in which case there is
// no standard way to determine what "kind" of symlink it is. Try
// deleting both ways.
if fs::remove_dir_all(path).is_err() {
let _ = fs::remove_file(path);
}
}
} else {
// On non-Windows, we check metadata not following symlinks. All
// symlinks are removed using remove_file.
if let Ok(metadata) = fs::symlink_metadata(path) {
if metadata.is_dir() {
let _ = fs::remove_dir_all(path);
} else {
let _ = fs::remove_file(path);
}
}
}
}
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