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use std::env;
use std::fs;
use std::io::{self, Read};
use std::path::{Path, PathBuf};
use rustc_data_structures::memmap::Mmap;
use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
use rustc_serialize::Encoder;
use rustc_session::Session;
const FILE_MAGIC: &[u8] = b"RSIC";
const HEADER_FORMAT_VERSION: u16 = 0;
const RUSTC_VERSION: Option<&str> = option_env!("CFG_VERSION");
pub(crate) fn write_file_header(stream: &mut FileEncoder, nightly_build: bool) {
stream.emit_raw_bytes(FILE_MAGIC);
stream
.emit_raw_bytes(&[(HEADER_FORMAT_VERSION >> 0) as u8, (HEADER_FORMAT_VERSION >> 8) as u8]);
let rustc_version = rustc_version(nightly_build);
assert_eq!(rustc_version.len(), (rustc_version.len() as u8) as usize);
stream.emit_raw_bytes(&[rustc_version.len() as u8]);
stream.emit_raw_bytes(rustc_version.as_bytes());
}
pub(crate) fn save_in<F>(sess: &Session, path_buf: PathBuf, name: &str, encode: F)
where
F: FnOnce(FileEncoder) -> FileEncodeResult,
{
debug!("save: storing data in {}", path_buf.display());
match fs::remove_file(&path_buf) {
Ok(()) => {
debug!("save: remove old file");
}
Err(err) if err.kind() == io::ErrorKind::NotFound => (),
Err(err) => {
sess.err(&format!(
"unable to delete old {} at `{}`: {}",
name,
path_buf.display(),
err
));
return;
}
}
let mut encoder = match FileEncoder::new(&path_buf) {
Ok(encoder) => encoder,
Err(err) => {
sess.err(&format!("failed to create {} at `{}`: {}", name, path_buf.display(), err));
return;
}
};
write_file_header(&mut encoder, sess.is_nightly_build());
match encode(encoder) {
Ok(position) => {
sess.prof.artifact_size(
&name.replace(' ', "_"),
path_buf.file_name().unwrap().to_string_lossy(),
position as u64,
);
debug!("save: data written to disk successfully");
}
Err(err) => {
sess.err(&format!("failed to write {} to `{}`: {}", name, path_buf.display(), err));
}
}
}
pub fn read_file(
report_incremental_info: bool,
path: &Path,
nightly_build: bool,
) -> io::Result<Option<(Mmap, usize)>> {
let file = match fs::File::open(path) {
Ok(file) => file,
Err(err) if err.kind() == io::ErrorKind::NotFound => return Ok(None),
Err(err) => return Err(err),
};
let mmap = unsafe { Mmap::map(file) }?;
let mut file = io::Cursor::new(&*mmap);
{
debug_assert!(FILE_MAGIC.len() == 4);
let mut file_magic = [0u8; 4];
file.read_exact(&mut file_magic)?;
if file_magic != FILE_MAGIC {
report_format_mismatch(report_incremental_info, path, "Wrong FILE_MAGIC");
return Ok(None);
}
}
{
debug_assert!(::std::mem::size_of_val(&HEADER_FORMAT_VERSION) == 2);
let mut header_format_version = [0u8; 2];
file.read_exact(&mut header_format_version)?;
let header_format_version =
(header_format_version[0] as u16) | ((header_format_version[1] as u16) << 8);
if header_format_version != HEADER_FORMAT_VERSION {
report_format_mismatch(report_incremental_info, path, "Wrong HEADER_FORMAT_VERSION");
return Ok(None);
}
}
{
let mut rustc_version_str_len = [0u8; 1];
file.read_exact(&mut rustc_version_str_len)?;
let rustc_version_str_len = rustc_version_str_len[0] as usize;
let mut buffer = vec![0; rustc_version_str_len];
file.read_exact(&mut buffer)?;
if buffer != rustc_version(nightly_build).as_bytes() {
report_format_mismatch(report_incremental_info, path, "Different compiler version");
return Ok(None);
}
}
let post_header_start_pos = file.position() as usize;
Ok(Some((mmap, post_header_start_pos)))
}
fn report_format_mismatch(report_incremental_info: bool, file: &Path, message: &str) {
debug!("read_file: {}", message);
if report_incremental_info {
eprintln!(
"[incremental] ignoring cache artifact `{}`: {}",
file.file_name().unwrap().to_string_lossy(),
message
);
}
}
fn rustc_version(nightly_build: bool) -> String {
if nightly_build {
if let Some(val) = env::var_os("RUSTC_FORCE_RUSTC_VERSION") {
return val.to_string_lossy().into_owned();
}
}
RUSTC_VERSION
.expect(
"Cannot use rustc without explicit version for \
incremental compilation",
)
.to_string()
}