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fish-shell/src/history.rs
ridiculousfish a996cafeeb Make history::remove take a &wstr instead of a WString 
While it does need to store the string, we also need to use the string after
storing it, so we aren't getting any advantage from passing by value. Just pass
by reference to simplify the call sites.
2024-04-15 09:47:46 -07:00

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//! Fish supports multiple shells writing to history at once. Here is its strategy:
//!
//! 1. All history files are append-only. Data, once written, is never modified.
//!
//! 2. A history file may be re-written ("vacuumed"). This involves reading in the file and writing a
//! new one, while performing maintenance tasks: discarding items in an LRU fashion until we reach
//! the desired maximum count, removing duplicates, and sorting them by timestamp (eventually, not
//! implemented yet). The new file is atomically moved into place via rename().
//!
//! 3. History files are mapped in via mmap(). Before the file is mapped, the file takes a fcntl read
//! lock. The purpose of this lock is to avoid seeing a transient state where partial data has been
//! written to the file.
//!
//! 4. History is appended to under a fcntl write lock.
//!
//! 5. The chaos_mode boolean can be set to true to do things like lower buffer sizes which can
//! trigger race conditions. This is useful for testing.
use crate::{common::cstr2wcstring, env::EnvVar, wcstringutil::trim};
use std::{
borrow::Cow,
collections::{BTreeMap, HashMap, HashSet, VecDeque},
ffi::CString,
fs::File,
io::{BufRead, Read, Seek, SeekFrom, Write},
mem,
num::NonZeroUsize,
ops::ControlFlow,
os::fd::{AsFd, AsRawFd, RawFd},
sync::{Arc, Mutex, MutexGuard},
time::{Duration, SystemTime, UNIX_EPOCH},
};
use bitflags::bitflags;
use libc::{fchmod, fchown, flock, fstat, LOCK_EX, LOCK_SH, LOCK_UN};
use lru::LruCache;
use nix::{fcntl::OFlag, sys::stat::Mode};
use rand::Rng;
use crate::{
ast::{Ast, Node},
common::{
str2wcstring, unescape_string, valid_var_name, wcs2zstring, write_loop, CancelChecker,
UnescapeStringStyle,
},
env::{EnvMode, EnvStack, Environment},
expand::{expand_one, ExpandFlags},
fallback::fish_mkstemp_cloexec,
fds::wopen_cloexec,
flog::{FLOG, FLOGF},
global_safety::RelaxedAtomicBool,
history::file::{append_history_item_to_buffer, HistoryFileContents},
io::IoStreams,
operation_context::{OperationContext, EXPANSION_LIMIT_BACKGROUND},
parse_constants::{ParseTreeFlags, StatementDecoration},
parse_util::{parse_util_detect_errors, parse_util_unescape_wildcards},
path::{
path_get_config, path_get_data, path_get_data_remoteness, path_is_valid, DirRemoteness,
},
threads::{assert_is_background_thread, iothread_perform},
util::find_subslice,
wchar::prelude::*,
wcstringutil::subsequence_in_string,
wildcard::{wildcard_match, ANY_STRING},
wutil::{
file_id_for_fd, file_id_for_path, wgettext_fmt, wrealpath, wrename, wstat, wunlink, FileId,
INVALID_FILE_ID,
},
};
mod file;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum SearchType {
/// Search for commands exactly matching the given string.
Exact,
/// Search for commands containing the given string.
Contains,
/// Search for commands starting with the given string.
Prefix,
/// Search for commands containing the given glob pattern.
ContainsGlob,
/// Search for commands starting with the given glob pattern.
PrefixGlob,
/// Search for commands containing the given string as a subsequence
ContainsSubsequence,
/// Matches everything.
MatchEverything,
}
/// Ways that a history item may be written to disk (or omitted).
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum PersistenceMode {
/// The history item is written to disk normally
Disk,
/// The history item is stored in-memory only, not written to disk
Memory,
/// The history item is stored in-memory and deleted when a new item is added
Ephemeral,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum SearchDirection {
Forward,
Backward,
}
use self::file::time_to_seconds;
// Our history format is intended to be valid YAML. Here it is:
//
// - cmd: ssh blah blah blah
// when: 2348237
// paths:
// - /path/to/something
// - /path/to/something_else
//
// Newlines are replaced by \n. Backslashes are replaced by \\.
/// This is the history session ID we use by default if the user has not set env var fish_history.
const DFLT_FISH_HISTORY_SESSION_ID: &wstr = L!("fish");
/// When we rewrite the history, the number of items we keep.
// FIXME: https://github.com/rust-lang/rust/issues/67441
const HISTORY_SAVE_MAX: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(1024 * 256) };
/// Default buffer size for flushing to the history file.
const HISTORY_OUTPUT_BUFFER_SIZE: usize = 64 * 1024;
/// The file access mode we use for creating history files
const HISTORY_FILE_MODE: Mode = Mode::from_bits_truncate(0o600);
/// How many times we retry to save
/// Saving may fail if the file is modified in between our opening
/// the file and taking the lock
const MAX_SAVE_TRIES: usize = 1024;
/// If the size of `buffer` is at least `min_size`, output the contents `buffer` to `fd`,
/// and clear the string.
fn flush_to_fd(buffer: &mut Vec<u8>, fd: RawFd, min_size: usize) -> std::io::Result<()> {
if buffer.is_empty() || buffer.len() < min_size {
return Ok(());
}
write_loop(&fd, buffer)?;
buffer.clear();
return Ok(());
}
struct TimeProfiler {
what: &'static str,
start: SystemTime,
}
impl TimeProfiler {
fn new(what: &'static str) -> Self {
let start = SystemTime::now();
Self { what, start }
}
}
impl Drop for TimeProfiler {
fn drop(&mut self) {
if let Ok(duration) = self.start.elapsed() {
FLOGF!(
profile_history,
"%s: %d.%06d ms",
self.what,
duration.as_millis() as u64, // todo!("remove cast")
(duration.as_nanos() / 1000) as u64 // todo!("remove cast")
)
} else {
FLOGF!(profile_history, "%s: ??? ms", self.what)
}
}
}
trait LruCacheExt {
/// Function to add a history item.
fn add_item(&mut self, item: HistoryItem);
}
impl LruCacheExt for LruCache<WString, HistoryItem> {
fn add_item(&mut self, item: HistoryItem) {
// Skip empty items.
if item.is_empty() {
return;
}
// See if it's in the cache. If it is, update the timestamp. If not, we create a new node
// and add it. Note that calling get_node promotes the node to the front.
let key = item.str();
if let Some(node) = self.get_mut(key) {
node.creation_timestamp = SystemTime::max(node.timestamp(), item.timestamp());
// What to do about paths here? Let's just ignore them.
} else {
self.put(key.to_owned(), item);
}
}
}
/// Returns the path for the history file for the given `session_id`, or `None` if it could not be
/// loaded. If `suffix` is provided, append that suffix to the path; this is used for temporary files.
fn history_filename(session_id: &wstr, suffix: &wstr) -> Option<WString> {
if session_id.is_empty() {
return None;
}
let mut result = path_get_data()?;
result.push('/');
result.push_utfstr(session_id);
result.push_utfstr(L!("_history"));
result.push_utfstr(suffix);
Some(result)
}
pub type PathList = Vec<WString>;
pub type HistoryIdentifier = u64;
#[derive(Clone, Debug)]
pub struct HistoryItem {
/// The actual contents of the entry.
contents: WString,
/// Original creation time for the entry.
creation_timestamp: SystemTime,
/// Paths that we require to be valid for this item to be autosuggested.
required_paths: Vec<WString>,
/// Sometimes unique identifier used for hinting.
identifier: HistoryIdentifier,
/// Whether to write this item to disk.
persist_mode: PersistenceMode,
}
impl HistoryItem {
/// Construct from a text, timestamp, and optional identifier.
/// If `persist_mode` is not [`PersistenceMode::Disk`], then do not write this item to disk.
pub fn new(
s: WString,
when: SystemTime, /*=0*/
ident: HistoryIdentifier, /*=0*/
persist_mode: PersistenceMode, /*=Disk*/
) -> Self {
Self {
contents: s,
creation_timestamp: when,
required_paths: vec![],
identifier: ident,
persist_mode,
}
}
/// Returns the text as a string.
pub fn str(&self) -> &wstr {
&self.contents
}
/// Returns whether the text is empty.
pub fn is_empty(&self) -> bool {
self.contents.is_empty()
}
/// Returns whether our contents matches a search term.
pub fn matches_search(&self, term: &wstr, typ: SearchType, case_sensitive: bool) -> bool {
// Note that 'term' has already been lowercased when constructing the
// search object if we're doing a case insensitive search.
let content_to_match = if case_sensitive {
Cow::Borrowed(&self.contents)
} else {
Cow::Owned(self.contents.to_lowercase())
};
match typ {
SearchType::Exact => term == *content_to_match,
SearchType::Contains => {
find_subslice(term.as_slice(), content_to_match.as_slice()).is_some()
}
SearchType::Prefix => content_to_match.as_slice().starts_with(term.as_slice()),
SearchType::ContainsGlob => {
let mut pat = parse_util_unescape_wildcards(term);
if !pat.starts_with(ANY_STRING) {
pat.insert(0, ANY_STRING);
}
if !pat.ends_with(ANY_STRING) {
pat.push(ANY_STRING);
}
wildcard_match(content_to_match.as_ref(), &pat, false)
}
SearchType::PrefixGlob => {
let mut pat = parse_util_unescape_wildcards(term);
if !pat.ends_with(ANY_STRING) {
pat.push(ANY_STRING);
}
wildcard_match(content_to_match.as_ref(), &pat, false)
}
SearchType::ContainsSubsequence => subsequence_in_string(term, &content_to_match),
SearchType::MatchEverything => true,
}
}
/// Returns the timestamp for creating this history item.
pub fn timestamp(&self) -> SystemTime {
self.creation_timestamp
}
/// Returns whether this item should be persisted (written to disk).
pub fn should_write_to_disk(&self) -> bool {
self.persist_mode == PersistenceMode::Disk
}
/// Get the list of arguments which referred to files.
/// This is used for autosuggestion hinting.
pub fn get_required_paths(&self) -> &[WString] {
&self.required_paths
}
/// Set the list of arguments which referred to files.
/// This is used for autosuggestion hinting.
pub fn set_required_paths(&mut self, paths: Vec<WString>) {
self.required_paths = paths;
}
/// We can merge two items if they are the same command. We use the more recent timestamp, more
/// recent identifier, and the longer list of required paths.
fn merge(&mut self, item: &HistoryItem) -> bool {
// We can only merge items if they agree on their text and persistence mode.
if self.contents != item.contents || self.persist_mode != item.persist_mode {
return false;
}
// Ok, merge this item.
self.creation_timestamp = self.creation_timestamp.max(item.creation_timestamp);
if self.required_paths.len() < item.required_paths.len() {
self.required_paths = item.required_paths.clone();
}
if self.identifier < item.identifier {
self.identifier = item.identifier;
}
true
}
}
static HISTORIES: Mutex<BTreeMap<WString, Arc<History>>> = Mutex::new(BTreeMap::new());
struct HistoryImpl {
/// The name of this list. Used for picking a suitable filename and for switching modes.
name: WString,
/// New items. Note that these are NOT discarded on save. We need to keep these around so we can
/// distinguish between items in our history and items in the history of other shells that were
/// started after we were started.
new_items: Vec<HistoryItem>,
/// The index of the first new item that we have not yet written.
first_unwritten_new_item_index: usize, // 0
/// Whether we have a pending item. If so, the most recently added item is ignored by
/// item_at_index.
has_pending_item: bool, // false
/// Whether we should disable saving to the file for a time.
disable_automatic_save_counter: u32, // 0
/// Deleted item contents.
/// Boolean describes if it should be deleted only in this session or in all
/// (used in deduplication).
deleted_items: HashMap<WString, bool>,
/// The buffer containing the history file contents.
file_contents: Option<HistoryFileContents>,
/// The file ID of the history file.
history_file_id: FileId, // INVALID_FILE_ID
/// The boundary timestamp distinguishes old items from new items. Items whose timestamps are <=
/// the boundary are considered "old". Items whose timestemps are > the boundary are new, and are
/// ignored by this instance (unless they came from this instance). The timestamp may be adjusted
/// by incorporate_external_changes().
boundary_timestamp: SystemTime,
/// The most recent "unique" identifier for a history item.
last_identifier: HistoryIdentifier, // 0
/// How many items we add until the next vacuum. Initially a random value.
countdown_to_vacuum: Option<usize>, // -1
/// Whether we've loaded old items.
loaded_old: bool, // false
/// List of old items, as offsets into out mmap data.
old_item_offsets: VecDeque<usize>,
}
/// If set, we gave up on file locking because it took too long.
/// Note this is shared among all history instances.
static ABANDONED_LOCKING: RelaxedAtomicBool = RelaxedAtomicBool::new(false);
impl HistoryImpl {
/// Add a new history item to the end. If `pending` is set, the item will not be returned by
/// `item_at_index()` until a call to `resolve_pending()`. Pending items are tracked with an
/// offset into the array of new items, so adding a non-pending item has the effect of resolving
/// all pending items.
fn add(
&mut self,
item: HistoryItem,
pending: bool, /*=false*/
do_save: bool, /*=true*/
) {
// We use empty items as sentinels to indicate the end of history.
// Do not allow them to be added (#6032).
if item.contents.is_empty() {
return;
}
// Try merging with the last item.
if let Some(last) = self.new_items.last_mut() {
if last.merge(&item) {
// We merged, so we don't have to add anything. Maybe this item was pending, but it just got
// merged with an item that is not pending, so pending just becomes false.
self.has_pending_item = false;
return;
}
}
// We have to add a new item.
self.new_items.push(item);
self.has_pending_item = pending;
if do_save {
self.save_unless_disabled();
}
}
/// Internal function.
fn clear_file_state(&mut self) {
// Erase everything we know about our file.
self.file_contents = None;
self.loaded_old = false;
self.old_item_offsets.clear();
}
/// Returns a timestamp for new items - see the implementation for a subtlety.
fn timestamp_now(&self) -> SystemTime {
let mut when = SystemTime::now();
// Big hack: do not allow timestamps equal to our boundary date. This is because we include
// items whose timestamps are equal to our boundary when reading old history, so we can catch
// "just closed" items. But this means that we may interpret our own items, that we just wrote,
// as old items, if we wrote them in the same second as our birthdate.
if when.duration_since(UNIX_EPOCH).ok().map(|d| d.as_secs())
== self
.boundary_timestamp
.duration_since(UNIX_EPOCH)
.ok()
.map(|d| d.as_secs())
{
when += Duration::from_secs(1);
}
when
}
/// Returns a new item identifier, incrementing our counter.
fn next_identifier(&mut self) -> HistoryIdentifier {
self.last_identifier += 1;
self.last_identifier
}
/// Figure out the offsets of our file contents.
fn populate_from_file_contents(&mut self) {
self.old_item_offsets.clear();
if let Some(file_contents) = &self.file_contents {
let mut cursor = 0;
while let Some(offset) =
file_contents.offset_of_next_item(&mut cursor, Some(self.boundary_timestamp))
{
// Remember this item.
self.old_item_offsets.push_back(offset);
}
}
FLOGF!(history, "Loaded %lu old items", self.old_item_offsets.len());
}
/// Loads old items if necessary.
fn load_old_if_needed(&mut self) {
if self.loaded_old {
return;
}
self.loaded_old = true;
let _profiler = TimeProfiler::new("load_old");
if let Some(filename) = history_filename(&self.name, L!("")) {
let Ok(mut file) = wopen_cloexec(&filename, OFlag::O_RDONLY, Mode::empty()) else {
return;
};
// Take a read lock to guard against someone else appending. This is released after
// getting the file's length. We will read the file after releasing the lock, but that's
// not a problem, because we never modify already written data. In short, the purpose of
// this lock is to ensure we don't see the file size change mid-update.
//
// We may fail to lock (e.g. on lockless NFS - see issue #685. In that case, we proceed
// as if it did not fail. The risk is that we may get an incomplete history item; this
// is unlikely because we only treat an item as valid if it has a terminating newline.
let locked = unsafe { Self::maybe_lock_file(&mut file, LOCK_SH) };
self.file_contents = HistoryFileContents::create(&mut file);
self.history_file_id = if self.file_contents.is_some() {
file_id_for_fd(file.as_fd())
} else {
INVALID_FILE_ID
};
if locked {
unsafe {
Self::unlock_file(&mut file);
}
}
let _profiler = TimeProfiler::new("populate_from_file_contents");
self.populate_from_file_contents();
}
}
/// Deletes duplicates in new_items.
fn compact_new_items(&mut self) {
// Keep only the most recent items with the given contents.
let mut seen = HashSet::new();
for idx in (0..self.new_items.len()).rev() {
let item = &self.new_items[idx];
// Only compact persisted items.
if !item.should_write_to_disk() {
continue;
}
if !seen.insert(item.contents.to_owned()) {
// This item was not inserted because it was already in the set, so delete the item at
// this index.
self.new_items.remove(idx);
if idx < self.first_unwritten_new_item_index {
// Decrement first_unwritten_new_item_index if we are deleting a previously written
// item.
self.first_unwritten_new_item_index -= 1;
}
}
}
}
/// Removes trailing ephemeral items.
/// Ephemeral items have leading spaces, and can only be retrieved immediately; adding any item
/// removes them.
fn remove_ephemeral_items(&mut self) {
while matches!(
self.new_items.last(),
Some(&HistoryItem {
persist_mode: PersistenceMode::Ephemeral,
..
})
) {
self.new_items.pop();
}
self.first_unwritten_new_item_index =
usize::min(self.first_unwritten_new_item_index, self.new_items.len());
}
/// Given the fd of an existing history file, write a new history file to `dst_fd`.
/// Returns false on error, true on success
fn rewrite_to_temporary_file(&self, existing_file: Option<&mut File>, dst: &mut File) -> bool {
// We are reading FROM existing_fd and writing TO dst_fd
// Make an LRU cache to save only the last N elements.
let mut lru = LruCache::new(HISTORY_SAVE_MAX);
// Read in existing items (which may have changed out from underneath us, so don't trust our
// old file contents).
if let Some(existing_file) = existing_file {
if let Some(local_file) = HistoryFileContents::create(existing_file) {
let mut cursor = 0;
while let Some(offset) = local_file.offset_of_next_item(&mut cursor, None) {
// Try decoding an old item.
let Some(old_item) = local_file.decode_item(offset) else {
continue;
};
// If old item is newer than session always erase if in deleted.
if old_item.timestamp() > self.boundary_timestamp {
if old_item.is_empty() || self.deleted_items.contains_key(old_item.str()) {
continue;
}
lru.add_item(old_item);
} else {
// If old item is older and in deleted items don't erase if added by
// clear_session.
if old_item.is_empty()
|| self.deleted_items.get(old_item.str()) == Some(&false)
{
continue;
}
// Add this old item.
lru.add_item(old_item);
}
}
}
}
// Insert any unwritten new items
for item in self
.new_items
.iter()
.skip(self.first_unwritten_new_item_index)
{
if item.should_write_to_disk() {
lru.add_item(item.clone());
}
}
// Stable-sort our items by timestamp
// This is because we may have read "old" items with a later timestamp than our "new" items
// This is the essential step that roughly orders items by history
let mut items: Vec<_> = lru.into_iter().map(|(_key, item)| item).collect();
items.sort_by_key(HistoryItem::timestamp);
// Write them out.
let mut err = None;
let mut buffer = Vec::with_capacity(HISTORY_OUTPUT_BUFFER_SIZE + 128);
for item in items {
append_history_item_to_buffer(&item, &mut buffer);
if let Err(e) = flush_to_fd(&mut buffer, dst.as_raw_fd(), HISTORY_OUTPUT_BUFFER_SIZE) {
err = Some(e);
break;
}
}
if let Some(err) = err {
FLOGF!(
history_file,
"Error %d when writing to temporary history file",
err.raw_os_error().unwrap_or_default()
);
false
} else {
flush_to_fd(&mut buffer, dst.as_raw_fd(), 0).is_ok()
}
}
/// Saves history by rewriting the file.
fn save_internal_via_rewrite(&mut self) {
FLOGF!(
history,
"Saving %lu items via rewrite",
self.new_items.len() - self.first_unwritten_new_item_index
);
// We want to rewrite the file, while holding the lock for as briefly as possible
// To do this, we speculatively write a file, and then lock and see if our original file changed
// Repeat until we succeed or give up
let Some(possibly_indirect_target_name) = history_filename(&self.name, L!("")) else {
return;
};
let Some(tmp_name_template) = history_filename(&self.name, L!(".XXXXXX")) else {
return;
};
// If the history file is a symlink, we want to rewrite the real file so long as we can find it.
let target_name =
wrealpath(&possibly_indirect_target_name).unwrap_or(possibly_indirect_target_name);
// Make our temporary file
let Some((mut tmp_file, tmp_name)) = create_temporary_file(&tmp_name_template) else {
return;
};
let mut done = false;
for _i in 0..MAX_SAVE_TRIES {
if done {
break;
}
let target_file_before = wopen_cloexec(
&target_name,
OFlag::O_RDONLY | OFlag::O_CREAT,
HISTORY_FILE_MODE,
);
let orig_file_id = target_file_before
.as_ref()
.map(|fd| file_id_for_fd(fd.as_fd()))
.unwrap_or(INVALID_FILE_ID);
// Open any target file, but do not lock it right away
if !self.rewrite_to_temporary_file(target_file_before.ok().as_mut(), &mut tmp_file) {
// Failed to write, no good
break;
}
// The crux! We rewrote the history file; see if the history file changed while we
// were rewriting it. Make an effort to take the lock before checking, to avoid racing.
// If the open fails, then proceed; this may be because there is no current history
let mut new_file_id = INVALID_FILE_ID;
let mut target_fd_after = wopen_cloexec(&target_name, OFlag::O_RDONLY, Mode::empty());
if let Ok(target_fd_after) = target_fd_after.as_mut() {
// critical to take the lock before checking file IDs,
// and hold it until after we are done replacing.
// Also critical to check the file at the path, NOT based on our fd.
// It's only OK to replace the file while holding the lock.
// Note any lock is released when target_fd_after is closed.
unsafe {
Self::maybe_lock_file(target_fd_after, LOCK_EX);
}
new_file_id = file_id_for_path(&target_name);
}
let can_replace_file = new_file_id == orig_file_id || new_file_id == INVALID_FILE_ID;
if !can_replace_file {
// The file has changed, so we're going to re-read it
// Truncate our tmp_file so we can reuse it
if tmp_file.set_len(0).is_err() || tmp_file.seek(SeekFrom::Start(0)).is_err() {
FLOGF!(
history_file,
"Error %d when truncating temporary history file",
errno::errno().0
);
}
} else {
// The file is unchanged, or the new file doesn't exist or we can't read it
// We also attempted to take the lock, so we feel confident in replacing it
// Ensure we maintain the ownership and permissions of the original (#2355). If the
// stat fails, we assume (hope) our default permissions are correct. This
// corresponds to e.g. someone running sudo -E as the very first command. If they
// did, it would be tricky to set the permissions correctly. (bash doesn't get this
// case right either).
if let Ok(target_fd_after) = target_fd_after.as_ref() {
let mut sbuf: libc::stat = unsafe { mem::zeroed() };
if unsafe { fstat(target_fd_after.as_raw_fd(), &mut sbuf) } >= 0 {
if unsafe { fchown(tmp_file.as_raw_fd(), sbuf.st_uid, sbuf.st_gid) } == -1 {
FLOGF!(
history_file,
"Error %d when changing ownership of history file",
errno::errno().0
);
}
if unsafe { fchmod(tmp_file.as_raw_fd(), sbuf.st_mode) } == -1 {
FLOGF!(
history_file,
"Error %d when changing mode of history file",
errno::errno().0,
);
}
}
}
// Slide it into place
if wrename(&tmp_name, &target_name) == -1 {
FLOG!(
error,
wgettext_fmt!(
"Error when renaming history file: %s",
errno::errno().to_string()
)
);
}
// We did it
done = true;
}
drop(target_fd_after);
}
// Ensure we never leave the old file around
let _ = wunlink(&tmp_name);
if done {
// We've saved everything, so we have no more unsaved items.
self.first_unwritten_new_item_index = self.new_items.len();
// We deleted our deleted items.
self.deleted_items.clear();
// Our history has been written to the file, so clear our state so we can re-reference the
// file.
self.clear_file_state();
}
}
/// Saves history by appending to the file.
fn save_internal_via_appending(&mut self) -> bool {
FLOGF!(
history,
"Saving %lu items via appending",
self.new_items.len() - self.first_unwritten_new_item_index
);
// No deleting allowed.
assert!(self.deleted_items.is_empty());
let mut ok = false;
// If the file is different (someone vacuumed it) then we need to update our mmap.
let mut file_changed = false;
// Get the path to the real history file.
let Some(history_path) = history_filename(&self.name, L!("")) else {
return true;
};
// We are going to open the file, lock it, append to it, and then close it
// After locking it, we need to stat the file at the path; if there is a new file there, it
// means the file was replaced and we have to try again.
// Limit our max tries so we don't do this forever.
let mut history_file = None;
for _i in 0..MAX_SAVE_TRIES {
let Ok(mut file) = wopen_cloexec(
&history_path,
OFlag::O_WRONLY | OFlag::O_APPEND,
Mode::empty(),
) else {
// can't open, we're hosed
break;
};
// Exclusive lock on the entire file. This is released when we close the file (below). This
// may fail on (e.g.) lockless NFS. If so, proceed as if it did not fail; the risk is that
// we may get interleaved history items, which is considered better than no history, or
// forcing everything through the slow copy-move mode. We try to minimize this possibility
// by writing with O_APPEND.
unsafe {
Self::maybe_lock_file(&mut file, LOCK_EX);
}
let file_id = file_id_for_fd(file.as_fd());
if file_id_for_path(&history_path) == file_id {
// File IDs match, so the file we opened is still at that path
// We're going to use this fd
if file_id != self.history_file_id {
file_changed = true;
}
history_file = Some(file);
break;
}
}
if let Some(history_file) = history_file {
// We (hopefully successfully) took the exclusive lock. Append to the file.
// Note that this is sketchy for a few reasons:
// - Another shell may have appended its own items with a later timestamp, so our file may
// no longer be sorted by timestamp.
// - Another shell may have appended the same items, so our file may now contain
// duplicates.
//
// We cannot modify any previous parts of our file, because other instances may be reading
// those portions. We can only append.
//
// Originally we always rewrote the file on saving, which avoided both of these problems.
// However, appending allows us to save history after every command, which is nice!
//
// Periodically we "clean up" the file by rewriting it, so that most of the time it doesn't
// have duplicates, although we don't yet sort by timestamp (the timestamp isn't really used
// for much anyways).
// So far so good. Write all items at or after first_unwritten_new_item_index. Note that we
// write even a pending item - pending items are ignored by history within the command
// itself, but should still be written to the file.
// TODO: consider filling the buffer ahead of time, so we can just lock, splat, and unlock?
let mut res = Ok(());
// Use a small buffer size for appending, we usually only have 1 item
let mut buffer = Vec::new();
while self.first_unwritten_new_item_index < self.new_items.len() {
let item = &self.new_items[self.first_unwritten_new_item_index];
if item.should_write_to_disk() {
append_history_item_to_buffer(item, &mut buffer);
res = flush_to_fd(
&mut buffer,
history_file.as_raw_fd(),
HISTORY_OUTPUT_BUFFER_SIZE,
);
if res.is_err() {
break;
}
}
// We wrote or skipped this item, hooray.
self.first_unwritten_new_item_index += 1;
}
if res.is_ok() {
res = flush_to_fd(&mut buffer, history_file.as_raw_fd(), 0);
}
// Since we just modified the file, update our history_file_id to match its current state
// Otherwise we'll think the file has been changed by someone else the next time we go to
// write.
// We don't update the mapping since we only appended to the file, and everything we
// appended remains in our new_items
self.history_file_id = file_id_for_fd(history_file.as_fd());
ok = res.is_ok();
drop(history_file);
}
// If someone has replaced the file, forget our file state.
if file_changed {
self.clear_file_state();
}
ok
}
/// Saves history.
fn save(&mut self, vacuum: bool) {
// Nothing to do if there's no new items.
if self.first_unwritten_new_item_index >= self.new_items.len()
&& self.deleted_items.is_empty()
{
return;
}
if history_filename(&self.name, L!("")).is_none() {
// We're in the "incognito" mode. Pretend we've saved the history.
self.first_unwritten_new_item_index = self.new_items.len();
self.deleted_items.clear();
self.clear_file_state();
}
// Compact our new items so we don't have duplicates.
self.compact_new_items();
// Try saving. If we have items to delete, we have to rewrite the file. If we do not, we can
// append to it.
let mut ok = false;
if !vacuum && self.deleted_items.is_empty() {
// Try doing a fast append.
ok = self.save_internal_via_appending();
if !ok {
FLOG!(history, "Appending failed");
}
}
if !ok {
// We did not or could not append; rewrite the file ("vacuum" it).
self.save_internal_via_rewrite();
}
}
/// Saves history unless doing so is disabled.
fn save_unless_disabled(&mut self) {
// Respect disable_automatic_save_counter.
if self.disable_automatic_save_counter > 0 {
return;
}
// We may or may not vacuum. We try to vacuum every kVacuumFrequency items, but start the
// countdown at a random number so that even if the user never runs more than 25 commands, we'll
// eventually vacuum. If countdown_to_vacuum is None, it means we haven't yet picked a value for
// the counter.
let vacuum_frequency = 25;
let countdown_to_vacuum = self
.countdown_to_vacuum
.get_or_insert_with(|| rand::thread_rng().gen_range(0..vacuum_frequency));
// Determine if we're going to vacuum.
let mut vacuum = false;
if *countdown_to_vacuum == 0 {
*countdown_to_vacuum = vacuum_frequency;
vacuum = true;
}
// Update our countdown.
assert!(*countdown_to_vacuum > 0);
*countdown_to_vacuum -= 1;
// This might be a good candidate for moving to a background thread.
let _profiler = TimeProfiler::new(if vacuum {
"save vacuum"
} else {
"save no vacuum"
});
self.save(vacuum);
}
fn new(name: WString) -> Self {
Self {
name,
new_items: vec![],
first_unwritten_new_item_index: 0,
has_pending_item: false,
disable_automatic_save_counter: 0,
deleted_items: HashMap::new(),
file_contents: None,
history_file_id: INVALID_FILE_ID,
boundary_timestamp: SystemTime::now(),
last_identifier: 0,
countdown_to_vacuum: None,
loaded_old: false,
old_item_offsets: VecDeque::new(),
}
}
/// Returns whether this is using the default name.
fn is_default(&self) -> bool {
self.name == DFLT_FISH_HISTORY_SESSION_ID
}
/// Determines whether the history is empty. Unfortunately this cannot be const, since it may
/// require populating the history.
fn is_empty(&mut self) -> bool {
// If we have new items, we're not empty.
if !self.new_items.is_empty() {
return false;
}
if self.loaded_old {
// If we've loaded old items, see if we have any offsets.
self.old_item_offsets.is_empty()
} else {
// If we have not loaded old items, don't actually load them (which may be expensive); just
// stat the file and see if it exists and is nonempty.
let Some(where_) = history_filename(&self.name, L!("")) else {
return true;
};
if let Ok(md) = wstat(&where_) {
// We're empty if the file is empty.
md.len() == 0
} else {
// Access failed, assume missing.
true
}
}
}
/// Remove a history item.
fn remove(&mut self, str_to_remove: &wstr) {
// Add to our list of deleted items.
self.deleted_items.insert(str_to_remove.to_owned(), false);
for idx in (0..self.new_items.len()).rev() {
let matched = self.new_items[idx].str() == str_to_remove;
if matched {
self.new_items.remove(idx);
// If this index is before our first_unwritten_new_item_index, then subtract one from
// that index so it stays pointing at the same item. If it is equal to or larger, then
// we have not yet written this item, so we don't have to adjust the index.
if idx < self.first_unwritten_new_item_index {
self.first_unwritten_new_item_index -= 1;
}
}
}
assert!(self.first_unwritten_new_item_index <= self.new_items.len());
}
/// Resolves any pending history items, so that they may be returned in history searches.
fn resolve_pending(&mut self) {
self.has_pending_item = false;
}
/// Enable / disable automatic saving. Main thread only!
fn disable_automatic_saving(&mut self) {
self.disable_automatic_save_counter += 1;
assert!(self.disable_automatic_save_counter != 0); // overflow!
}
fn enable_automatic_saving(&mut self) {
assert!(self.disable_automatic_save_counter > 0); // negative overflow!
self.disable_automatic_save_counter -= 1;
self.save_unless_disabled();
}
/// Irreversibly clears history.
fn clear(&mut self) {
self.new_items.clear();
self.deleted_items.clear();
self.first_unwritten_new_item_index = 0;
self.old_item_offsets.clear();
if let Some(filename) = history_filename(&self.name, L!("")) {
wunlink(&filename);
}
self.clear_file_state();
}
/// Clears only session.
fn clear_session(&mut self) {
for item in &self.new_items {
self.deleted_items.insert(item.str().to_owned(), true);
}
self.new_items.clear();
self.first_unwritten_new_item_index = 0;
}
/// Populates from older location (in config path, rather than data path).
/// This is accomplished by clearing ourselves, and copying the contents of the old history
/// file to the new history file.
/// The new contents will automatically be re-mapped later.
fn populate_from_config_path(&mut self) {
let Some(new_file) = history_filename(&self.name, L!("")) else {
return;
};
let Some(mut old_file) = path_get_config() else {
return;
};
old_file.push('/');
old_file.push_utfstr(&self.name);
old_file.push_str("_history");
let Ok(mut src_file) = wopen_cloexec(&old_file, OFlag::O_RDONLY, Mode::empty()) else {
return;
};
// Clear must come after we've retrieved the new_file name, and before we open
// destination file descriptor, since it destroys the name and the file.
self.clear();
let Ok(mut dst_file) = wopen_cloexec(
&new_file,
OFlag::O_WRONLY | OFlag::O_CREAT,
HISTORY_FILE_MODE,
) else {
FLOG!(history_file, "Error when writing history file");
return;
};
let mut buf = [0; libc::BUFSIZ as usize];
while let Ok(n) = src_file.read(&mut buf) {
if n == 0 {
break;
}
if dst_file.write(&buf[..n]).is_err() {
// This message does not have high enough priority to be shown by default.
FLOG!(history_file, "Error when writing history file");
break;
}
}
}
/// Import a bash command history file. Bash's history format is very simple: just lines with
/// `#`s for comments. Ignore a few commands that are bash-specific. It makes no attempt to
/// handle multiline commands. We can't actually parse bash syntax and the bash history file
/// does not unambiguously encode multiline commands.
fn populate_from_bash<R: BufRead>(&mut self, contents: R) {
// Process the entire history file until EOF is observed.
// Pretend all items were created at this time.
let when = self.timestamp_now();
for line in contents.split(b'\n') {
let Ok(line) = line else {
break;
};
let wide_line = trim(str2wcstring(&line), None);
// Add this line if it doesn't contain anything we know we can't handle.
if should_import_bash_history_line(&wide_line) {
self.add(
HistoryItem::new(wide_line, when, 0, PersistenceMode::Disk),
/*pending=*/ false,
/*do_save=*/ false,
);
}
}
self.save_unless_disabled();
}
/// Incorporates the history of other shells into this history.
fn incorporate_external_changes(&mut self) {
// To incorporate new items, we simply update our timestamp to now, so that items from previous
// instances get added. We then clear the file state so that we remap the file. Note that this
// is somewhat expensive because we will be going back over old items. An optimization would be
// to preserve old_item_offsets so that they don't have to be recomputed. (However, then items
// *deleted* in other instances would not show up here).
let new_timestamp = SystemTime::now();
// If for some reason the clock went backwards, we don't want to start dropping items; therefore
// we only do work if time has progressed. This also makes multiple calls cheap.
if new_timestamp > self.boundary_timestamp {
self.boundary_timestamp = new_timestamp;
self.clear_file_state();
// We also need to erase new items, since we go through those first, and that means we
// will not properly interleave them with items from other instances.
// We'll pick them up from the file (#2312)
// TODO: this will drop items that had no_persist set, how can we avoid that while still
// properly interleaving?
self.save(false);
self.new_items.clear();
self.first_unwritten_new_item_index = 0;
}
}
/// Gets all the history into a list. This is intended for the $history environment variable.
/// This may be long!
fn get_history(&mut self) -> Vec<WString> {
let mut result = vec![];
// If we have a pending item, we skip the first encountered (i.e. last) new item.
let mut next_is_pending = self.has_pending_item;
let mut seen = HashSet::new();
// Append new items.
for item in self.new_items.iter().rev() {
// Skip a pending item if we have one.
if next_is_pending {
next_is_pending = false;
continue;
}
if seen.insert(item.str().to_owned()) {
result.push(item.str().to_owned())
}
}
// Append old items.
self.load_old_if_needed();
for &offset in self.old_item_offsets.iter().rev() {
let Some(item) = self.file_contents.as_ref().unwrap().decode_item(offset) else {
continue;
};
if seen.insert(item.str().to_owned()) {
result.push(item.str().to_owned());
}
}
result
}
/// Let indexes be a list of one-based indexes into the history, matching the interpretation of
/// $history. That is, $history[1] is the most recently executed command. Values less than one
/// are skipped. Return a mapping from index to history item text.
fn items_at_indexes(
&mut self,
indexes: impl IntoIterator<Item = usize>,
) -> HashMap<usize, WString> {
let mut result = HashMap::new();
for idx in indexes {
// If this is the first time the index is encountered, we have to go fetch the item.
#[allow(clippy::map_entry)] // looks worse
if !result.contains_key(&idx) {
// New key.
let contents = match self.item_at_index(idx) {
None => WString::new(),
Some(Cow::Borrowed(HistoryItem { contents, .. })) => contents.clone(),
Some(Cow::Owned(HistoryItem { contents, .. })) => contents,
};
result.insert(idx, contents);
}
}
result
}
/// Sets the valid file paths for the history item with the given identifier.
fn set_valid_file_paths(&mut self, valid_file_paths: Vec<WString>, ident: HistoryIdentifier) {
// 0 identifier is used to mean "not necessary".
if ident == 0 {
return;
}
// Look for an item with the given identifier. It is likely to be at the end of new_items.
for item in self.new_items.iter_mut().rev() {
if item.identifier == ident {
// found it
item.required_paths = valid_file_paths;
break;
}
}
}
/// Return the specified history at the specified index. 0 is the index of the current
/// commandline. (So the most recent item is at index 1.)
fn item_at_index(&mut self, mut idx: usize) -> Option<Cow<HistoryItem>> {
// 0 is considered an invalid index.
if idx == 0 {
return None;
}
idx -= 1;
// Determine how many "resolved" (non-pending) items we have. We can have at most one pending
// item, and it's always the last one.
let mut resolved_new_item_count = self.new_items.len();
if self.has_pending_item && resolved_new_item_count > 0 {
resolved_new_item_count -= 1;
}
// idx == 0 corresponds to the last resolved item.
if idx < resolved_new_item_count {
return Some(Cow::Borrowed(
&self.new_items[resolved_new_item_count - idx - 1],
));
}
// Now look in our old items.
idx -= resolved_new_item_count;
self.load_old_if_needed();
if let Some(file_contents) = &self.file_contents {
let old_item_count = self.old_item_offsets.len();
if idx < old_item_count {
// idx == 0 corresponds to last item in old_item_offsets.
let offset = self.old_item_offsets[old_item_count - idx - 1];
return file_contents.decode_item(offset).map(Cow::Owned);
}
}
// Index past the valid range, so return None.
return None;
}
/// Return the number of history entries.
fn size(&mut self) -> usize {
let mut new_item_count = self.new_items.len();
if self.has_pending_item && new_item_count > 0 {
new_item_count -= 1;
}
self.load_old_if_needed();
let old_item_count = self.old_item_offsets.len();
return new_item_count + old_item_count;
}
/// Maybe lock a history file.
/// Returns `true` if successful, `false` if locking was skipped.
///
/// # Safety
///
/// `fd` and `lock_type` must be valid arguments to `flock(2)`.
unsafe fn maybe_lock_file(file: &mut File, lock_type: libc::c_int) -> bool {
assert!(lock_type & LOCK_UN == 0, "Do not use lock_file to unlock");
let raw_fd = file.as_raw_fd();
// Don't lock if it took too long before, if we are simulating a failing lock, or if our history
// is on a remote filesystem.
if ABANDONED_LOCKING.load() {
return false;
}
if CHAOS_MODE.load() {
return false;
}
if path_get_data_remoteness() == DirRemoteness::remote {
return false;
}
let start_time = SystemTime::now();
let retval = unsafe { flock(raw_fd, lock_type) };
if let Ok(duration) = start_time.elapsed() {
if duration > Duration::from_millis(250) {
FLOG!(
warning,
wgettext_fmt!(
"Locking the history file took too long (%.3f seconds).",
duration.as_secs_f64()
)
);
ABANDONED_LOCKING.store(true);
}
}
retval != -1
}
/// Unlock a history file.
///
/// # Safety
///
/// `fd` must be a valid argument to `flock(2)` with `LOCK_UN`.
unsafe fn unlock_file(file: &mut File) {
unsafe {
libc::flock(file.as_raw_fd(), LOCK_UN);
}
}
}
// Returns the fd of an opened temporary file, or None on failure.
fn create_temporary_file(name_template: &wstr) -> Option<(File, WString)> {
for _attempt in 0..10 {
let narrow_str = wcs2zstring(name_template);
if let Ok((fd, narrow_str)) = fish_mkstemp_cloexec(narrow_str) {
return Some((fd, str2wcstring(narrow_str.to_bytes())));
}
}
None
}
fn string_could_be_path(potential_path: &wstr) -> bool {
// Assume that things with leading dashes aren't paths.
return !(potential_path.is_empty() || potential_path.starts_with('-'));
}
/// Perform a search of `hist` for `search_string`. Invoke a function `func` for each match. If
/// `func` returns [`ControlFlow::Break`], stop the search.
fn do_1_history_search(
hist: Arc<History>,
search_type: SearchType,
search_string: WString,
case_sensitive: bool,
mut func: impl FnMut(&HistoryItem) -> ControlFlow<(), ()>,
cancel_check: &CancelChecker,
) {
let mut searcher = HistorySearch::new_with(
hist,
search_string,
search_type,
if case_sensitive {
SearchFlags::empty()
} else {
SearchFlags::IGNORE_CASE
},
0,
);
while !cancel_check() && searcher.go_to_next_match(SearchDirection::Backward) {
if let ControlFlow::Break(()) = func(searcher.current_item()) {
break;
}
}
}
/// Formats a single history record, including a trailing newline.
///
/// Returns nothing. The only possible failure involves formatting the timestamp. If that happens we
/// simply omit the timestamp from the output.
fn format_history_record(
item: &HistoryItem,
show_time_format: Option<&str>,
null_terminate: bool,
) -> WString {
let mut result = WString::new();
let seconds = time_to_seconds(item.timestamp());
let seconds = seconds as libc::time_t;
let mut timestamp: libc::tm = unsafe { std::mem::zeroed() };
if let Some(show_time_format) = show_time_format.and_then(|s| CString::new(s).ok()) {
if !unsafe { libc::localtime_r(&seconds, &mut timestamp).is_null() } {
const max_tstamp_length: usize = 100;
let mut timestamp_str = [0_u8; max_tstamp_length];
// The libc crate fails to declare strftime on BSD.
#[cfg(bsd)]
extern "C" {
fn strftime(
buf: *mut libc::c_char,
maxsize: usize,
format: *const libc::c_char,
timeptr: *const libc::tm,
) -> usize;
}
#[cfg(not(bsd))]
use libc::strftime;
if unsafe {
strftime(
&mut timestamp_str[0] as *mut u8 as *mut libc::c_char,
max_tstamp_length,
show_time_format.as_ptr(),
&timestamp,
)
} != 0
{
result.push_utfstr(&cstr2wcstring(&timestamp_str[..]));
}
}
}
result.push_utfstr(item.str());
result.push(if null_terminate { '\0' } else { '\n' });
result
}
/// Decide whether we ought to import a bash history line into fish. This is a very crude heuristic.
fn should_import_bash_history_line(line: &wstr) -> bool {
if line.is_empty() {
return false;
}
// The following are Very naive tests!
// Skip comments.
if line.starts_with('#') {
return false;
}
// Skip lines with backticks because we don't have that syntax,
// Skip brace expansions and globs because they don't work like ours
// Skip lines that end with a backslash. We do not handle multiline commands from bash history.
if line.chars().any(|c| matches!(c, '`' | '{' | '*' | '\\')) {
return false;
}
// Skip lines with [[...]] and ((...)) since we don't handle those constructs.
// "<<" here is a proxy for heredocs (and herestrings).
for seq in [L!("[["), L!("]]"), L!("(("), L!("))"), L!("<<")] {
if find_subslice(seq, line.as_char_slice()).is_some() {
return false;
}
}
if Ast::parse(line, ParseTreeFlags::empty(), None).errored() {
return false;
}
// In doing this test do not allow incomplete strings. Hence the "false" argument.
let mut errors = Vec::new();
let _ = parse_util_detect_errors(line, Some(&mut errors), false);
errors.is_empty()
}
pub struct History(Mutex<HistoryImpl>);
impl History {
fn imp(&self) -> MutexGuard<HistoryImpl> {
self.0.lock().unwrap()
}
/// Privately add an item. If pending, the item will not be returned by history searches until a
/// call to resolve_pending. Any trailing ephemeral items are dropped.
/// Exposed for testing.
pub fn add(&self, item: HistoryItem, pending: bool /*=false*/) {
self.imp().add(item, pending, true)
}
pub fn add_commandline(&self, s: WString) {
let mut imp = self.imp();
let when = imp.timestamp_now();
let item = HistoryItem::new(s, when, 0, PersistenceMode::Disk);
imp.add(item, false, true)
}
pub fn new(name: &wstr) -> Arc<Self> {
Arc::new(Self(Mutex::new(HistoryImpl::new(name.to_owned()))))
}
/// Returns history with the given name, creating it if necessary.
pub fn with_name(name: &wstr) -> Arc<Self> {
let mut histories = HISTORIES.lock().unwrap();
if let Some(hist) = histories.get(name) {
Arc::clone(hist)
} else {
let hist = Self::new(name);
histories.insert(name.to_owned(), Arc::clone(&hist));
hist
}
}
/// Returns whether this is using the default name.
pub fn is_default(&self) -> bool {
self.imp().is_default()
}
/// Determines whether the history is empty.
pub fn is_empty(&self) -> bool {
self.imp().is_empty()
}
/// Remove a history item.
pub fn remove(&self, s: &wstr) {
self.imp().remove(s)
}
/// Remove any trailing ephemeral items.
pub fn remove_ephemeral_items(&self) {
self.imp().remove_ephemeral_items()
}
/// Add a new pending history item to the end, and then begin file detection on the items to
/// determine which arguments are paths. Arguments may be expanded (e.g. with PWD and variables)
/// using the given `vars`. The item has the given `persist_mode`.
pub fn add_pending_with_file_detection(
self: Arc<Self>,
s: &wstr,
vars: &EnvStack,
persist_mode: PersistenceMode, /*=disk*/
) {
// We use empty items as sentinels to indicate the end of history.
// Do not allow them to be added (#6032).
if s.is_empty() {
return;
}
// Find all arguments that look like they could be file paths.
let mut needs_sync_write = false;
let ast = Ast::parse(s, ParseTreeFlags::empty(), None);
let mut potential_paths = Vec::new();
for node in ast.walk() {
if let Some(arg) = node.as_argument() {
let potential_path = arg.source(s);
if string_could_be_path(potential_path) {
potential_paths.push(potential_path.to_owned());
}
} else if let Some(stmt) = node.as_decorated_statement() {
// Hack hack hack - if the command is likely to trigger an exit, then don't do
// background file detection, because we won't be able to write it to our history file
// before we exit.
// Also skip it for 'echo'. This is because echo doesn't take file paths, but also
// because the history file test wants to find the commands in the history file
// immediately after running them, so it can't tolerate the asynchronous file detection.
if stmt.decoration() == StatementDecoration::exec {
needs_sync_write = true;
}
let source = stmt.command.source(s);
let command = unescape_string(source, UnescapeStringStyle::default());
let command = command.as_deref().unwrap_or(source);
if [L!("exit"), L!("reboot"), L!("restart"), L!("echo")].contains(&command) {
needs_sync_write = true;
}
}
}
// If we got a path, we'll perform file detection for autosuggestion hinting.
let wants_file_detection = !potential_paths.is_empty() && !needs_sync_write;
let mut imp = self.imp();
// Make our history item.
let when = imp.timestamp_now();
let identifier = imp.next_identifier();
let item = HistoryItem::new(s.to_owned(), when, identifier, persist_mode);
if wants_file_detection {
imp.disable_automatic_saving();
// Add the item. Then check for which paths are valid on a background thread,
// and unblock the item.
// Don't hold the lock while we perform this file detection.
imp.add(item, /*pending=*/ true, /*do_save=*/ true);
drop(imp);
let vars_snapshot = vars.snapshot();
iothread_perform(move || {
// Don't hold the lock while we perform this file detection.
let validated_paths = expand_and_detect_paths(potential_paths, &vars_snapshot);
let mut imp = self.imp();
imp.set_valid_file_paths(validated_paths, identifier);
imp.enable_automatic_saving();
});
} else {
// Add the item.
// If we think we're about to exit, save immediately, regardless of any disabling. This may
// cause us to lose file hinting for some commands, but it beats losing history items.
imp.add(item, /*pending=*/ true, /*do_save=*/ true);
if needs_sync_write {
imp.save(false);
}
}
}
/// Resolves any pending history items, so that they may be returned in history searches.
pub fn resolve_pending(&self) {
self.imp().resolve_pending()
}
/// Saves history.
pub fn save(&self) {
self.imp().save(false)
}
/// Searches history.
#[allow(clippy::too_many_arguments)]
pub fn search(
self: &Arc<Self>,
search_type: SearchType,
search_args: &[&wstr],
show_time_format: Option<&str>,
max_items: usize,
case_sensitive: bool,
null_terminate: bool,
reverse: bool,
cancel_check: &CancelChecker,
streams: &mut IoStreams,
) -> bool {
let mut remaining = max_items;
let mut collected = Vec::new();
let mut output_error = false;
// The function we use to act on each item.
let mut func = |item: &HistoryItem| {
if remaining == 0 {
return ControlFlow::Break(());
}
remaining -= 1;
let formatted_record = format_history_record(item, show_time_format, null_terminate);
if reverse {
// We need to collect this for later.
collected.push(formatted_record);
} else {
// We can output this immediately.
if !streams.out.append(formatted_record) {
// This can happen if the user hit Ctrl-C to abort (maybe after the first page?).
output_error = true;
return ControlFlow::Break(());
}
}
ControlFlow::Continue(())
};
if search_args.is_empty() {
// The user had no search terms; just append everything.
do_1_history_search(
Arc::clone(self),
SearchType::MatchEverything,
WString::new(),
false,
&mut func,
cancel_check,
);
} else {
#[allow(clippy::unnecessary_to_owned)]
for search_string in search_args.iter().copied() {
if search_string.is_empty() {
streams
.err
.append(L!("Searching for the empty string isn't allowed"));
return false;
}
do_1_history_search(
Arc::clone(self),
search_type,
search_string.to_owned(),
case_sensitive,
&mut func,
cancel_check,
);
}
}
// Output any items we collected (which only happens in reverse).
for item in collected.into_iter().rev() {
if output_error {
break;
}
if !streams.out.append(item) {
// Don't force an error if output was aborted (typically via Ctrl-C/SIGINT); just don't
// try writing any more.
output_error = true;
}
}
// We are intentionally not returning false in case of an output error, as the user aborting the
// output early (the most common case) isn't a reason to exit w/ a non-zero status code.
true
}
/// Irreversibly clears history.
pub fn clear(&self) {
self.imp().clear()
}
/// Irreversibly clears history for the current session.
pub fn clear_session(&self) {
self.imp().clear_session()
}
/// Populates from older location (in config path, rather than data path).
pub fn populate_from_config_path(&self) {
self.imp().populate_from_config_path()
}
/// Populates from a bash history file.
pub fn populate_from_bash<R: BufRead>(&self, contents: R) {
self.imp().populate_from_bash(contents)
}
/// Incorporates the history of other shells into this history.
pub fn incorporate_external_changes(&self) {
self.imp().incorporate_external_changes()
}
/// Gets all the history into a list. This is intended for the $history environment variable.
/// This may be long!
pub fn get_history(&self) -> Vec<WString> {
self.imp().get_history()
}
/// Let indexes be a list of one-based indexes into the history, matching the interpretation of
/// `$history`. That is, `$history[1]` is the most recently executed command.
/// Returns a mapping from index to history item text.
pub fn items_at_indexes(
&self,
indexes: impl IntoIterator<Item = usize>,
) -> HashMap<usize, WString> {
self.imp().items_at_indexes(indexes)
}
/// Return the specified history at the specified index. 0 is the index of the current
/// commandline. (So the most recent item is at index 1.)
pub fn item_at_index(&self, idx: usize) -> Option<HistoryItem> {
self.imp().item_at_index(idx).map(Cow::into_owned)
}
/// Return the number of history entries.
pub fn size(&self) -> usize {
self.imp().size()
}
}
bitflags! {
/// Flags for history searching.
#[derive(Clone, Copy, Default)]
pub struct SearchFlags: u32 {
/// If set, ignore case.
const IGNORE_CASE = 1 << 0;
/// If set, do not deduplicate, which can help performance.
const NO_DEDUP = 1 << 1;
}
}
/// Support for searching a history backwards.
/// Note this does NOT de-duplicate; it is the caller's responsibility to do so.
pub struct HistorySearch {
/// The history in which we are searching.
history: Arc<History>,
/// The original search term.
orig_term: WString,
/// The (possibly lowercased) search term.
canon_term: WString,
/// Our search type.
search_type: SearchType, // history_search_type_t::contains
/// Our flags.
flags: SearchFlags, // 0
/// The current history item.
current_item: Option<HistoryItem>,
/// Index of the current history item.
current_index: usize, // 0
/// If deduping, the items we've seen.
deduper: HashSet<WString>,
}
impl HistorySearch {
pub fn new(hist: Arc<History>, s: WString) -> Self {
Self::new_with(hist, s, SearchType::Contains, SearchFlags::default(), 0)
}
pub fn new_with_type(hist: Arc<History>, s: WString, search_type: SearchType) -> Self {
Self::new_with(hist, s, search_type, SearchFlags::default(), 0)
}
pub fn new_with_flags(hist: Arc<History>, s: WString, flags: SearchFlags) -> Self {
Self::new_with(hist, s, SearchType::Contains, flags, 0)
}
/// Constructs a new history search.
pub fn new_with(
hist: Arc<History>,
s: WString,
search_type: SearchType,
flags: SearchFlags,
starting_index: usize,
) -> Self {
let mut search = Self {
history: hist,
orig_term: s.clone(),
canon_term: s,
search_type,
flags,
current_item: None,
current_index: starting_index,
deduper: HashSet::new(),
};
if search.ignores_case() {
search.canon_term = search.canon_term.to_lowercase();
}
search
}
/// Returns the original search term.
pub fn original_term(&self) -> &wstr {
&self.orig_term
}
pub fn prepare_to_search_after_deletion(&mut self) {
assert!(self.current_index != 0);
self.current_index -= 1;
self.current_item = None;
}
/// Finds the next search result. Returns `true` if one was found.
pub fn go_to_next_match(&mut self, direction: SearchDirection) -> bool {
let invalid_index = match direction {
SearchDirection::Backward => usize::MAX,
SearchDirection::Forward => 0,
};
if self.current_index == invalid_index {
return false;
}
let mut index = self.current_index;
loop {
// Backwards means increasing our index.
match direction {
SearchDirection::Backward => index += 1,
SearchDirection::Forward => index -= 1,
};
if self.current_index == invalid_index {
return false;
}
// We're done if it's empty or we cancelled.
let Some(item) = self.history.item_at_index(index) else {
return false;
};
// Look for an item that matches and (if deduping) that we haven't seen before.
if !item.matches_search(&self.canon_term, self.search_type, !self.ignores_case()) {
continue;
}
// Skip if deduplicating.
if self.dedup() && !self.deduper.insert(item.str().to_owned()) {
continue;
}
// This is our new item.
self.current_item = Some(item);
self.current_index = index;
return true;
}
}
/// Returns the current search result item.
///
/// # Panics
///
/// This function panics if there is no current item.
pub fn current_item(&self) -> &HistoryItem {
self.current_item.as_ref().expect("No current item")
}
/// Returns the current search result item contents.
///
/// # Panics
///
/// This function panics if there is no current item.
pub fn current_string(&self) -> &wstr {
self.current_item().str()
}
/// Returns the index of the current history item.
pub fn current_index(&self) -> usize {
self.current_index
}
/// Returns whether we are case insensitive.
pub fn ignores_case(&self) -> bool {
self.flags.contains(SearchFlags::IGNORE_CASE)
}
/// Returns whether we deduplicate items.
fn dedup(&self) -> bool {
!self.flags.contains(SearchFlags::NO_DEDUP)
}
}
/// Saves the new history to disk.
pub fn save_all() {
for hist in HISTORIES.lock().unwrap().values() {
hist.save();
}
}
/// Return the prefix for the files to be used for command and read history.
pub fn history_session_id(vars: &dyn Environment) -> WString {
history_session_id_from_var(vars.get(L!("fish_history")))
}
pub fn history_session_id_from_var(history_name_var: Option<EnvVar>) -> WString {
let Some(var) = history_name_var else {
return DFLT_FISH_HISTORY_SESSION_ID.to_owned();
};
let session_id = var.as_string();
if session_id.is_empty() || valid_var_name(&session_id) {
session_id
} else {
FLOG!(
error,
wgettext_fmt!(
"History session ID '%ls' is not a valid variable name. Falling back to `%ls`.",
&session_id,
DFLT_FISH_HISTORY_SESSION_ID
),
);
DFLT_FISH_HISTORY_SESSION_ID.to_owned()
}
}
/// Given a list of proposed paths and a context, perform variable and home directory expansion,
/// and detect if the result expands to a value which is also the path to a file.
/// Wildcard expansions are suppressed - see implementation comments for why.
///
/// This is used for autosuggestion hinting. If we add an item to history, and one of its arguments
/// refers to a file, then we only want to suggest it if there is a valid file there.
/// This does disk I/O and may only be called in a background thread.
pub fn expand_and_detect_paths<P: IntoIterator<Item = WString>>(
paths: P,
vars: &dyn Environment,
) -> Vec<WString> {
assert_is_background_thread();
let working_directory = vars.get_pwd_slash();
let ctx = OperationContext::background(vars, EXPANSION_LIMIT_BACKGROUND);
let mut result = Vec::new();
for path in paths {
// Suppress cmdsubs since we are on a background thread and don't want to execute fish
// script.
// Suppress wildcards because we want to suggest e.g. `rm *` even if the directory
// is empty (and so rm will fail); this is nevertheless a useful command because it
// confirms the directory is empty.
let mut expanded_path = path.clone();
if expand_one(
&mut expanded_path,
ExpandFlags::FAIL_ON_CMDSUBST | ExpandFlags::SKIP_WILDCARDS,
&ctx,
None,
) && path_is_valid(&expanded_path, &working_directory)
{
// Note we return the original (unexpanded) path.
result.push(path);
}
}
result
}
/// Given a list of proposed paths and a context, expand each one and see if it refers to a file.
/// Wildcard expansions are suppressed.
/// Returns `true` if `paths` is empty or every path is valid.
pub fn all_paths_are_valid<P: IntoIterator<Item = WString>>(
paths: P,
ctx: &OperationContext<'_>,
) -> bool {
assert_is_background_thread();
let working_directory = ctx.vars().get_pwd_slash();
for mut path in paths {
if ctx.check_cancel() {
return false;
}
if !expand_one(
&mut path,
ExpandFlags::FAIL_ON_CMDSUBST | ExpandFlags::SKIP_WILDCARDS,
ctx,
None,
) {
return false;
}
if !path_is_valid(&path, &working_directory) {
return false;
}
}
true
}
/// Sets private mode on. Once in private mode, it cannot be turned off.
pub fn start_private_mode(vars: &EnvStack) {
vars.set_one(L!("fish_history"), EnvMode::GLOBAL, L!("").to_owned());
vars.set_one(L!("fish_private_mode"), EnvMode::GLOBAL, L!("1").to_owned());
}
/// Queries private mode status.
pub fn in_private_mode(vars: &dyn Environment) -> bool {
vars.get_unless_empty(L!("fish_private_mode")).is_some()
}
/// Whether to force the read path instead of mmap. This is useful for testing.
static NEVER_MMAP: RelaxedAtomicBool = RelaxedAtomicBool::new(false);
/// Whether we're in maximum chaos mode, useful for testing.
/// This causes things like locks to fail.
pub static CHAOS_MODE: RelaxedAtomicBool = RelaxedAtomicBool::new(false);
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