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use super::{
base::CommandLineSearch, History, HistoryItem, HistoryItemId, HistorySessionId,
SearchDirection, SearchQuery,
};
use crate::{
result::{ReedlineError, ReedlineErrorVariants},
Result,
};
use std::{
collections::VecDeque,
fs::OpenOptions,
io::{BufRead, BufReader, BufWriter, Seek, SeekFrom, Write},
ops::{Deref, DerefMut},
path::PathBuf,
};
pub const HISTORY_SIZE: usize = 1000;
pub const NEWLINE_ESCAPE: &str = "<\\n>";
#[derive(Debug)]
pub struct FileBackedHistory {
capacity: usize,
entries: VecDeque<String>,
file: Option<PathBuf>,
len_on_disk: usize,
}
impl Default for FileBackedHistory {
fn default() -> Self {
Self::new(HISTORY_SIZE)
}
}
fn encode_entry(s: &str) -> String {
s.replace('\n', NEWLINE_ESCAPE)
}
fn decode_entry(s: &str) -> String {
s.replace(NEWLINE_ESCAPE, "\n")
}
impl History for FileBackedHistory {
fn save(&mut self, h: HistoryItem) -> Result<HistoryItem> {
let entry = h.command_line;
let entry_id = if self
.entries
.back()
.map_or(true, |previous| previous != &entry)
&& !entry.is_empty()
{
if self.entries.len() == self.capacity {
self.entries.pop_front();
self.len_on_disk = self.len_on_disk.saturating_sub(1);
}
self.entries.push_back(entry.to_string());
Some(HistoryItemId::new((self.entries.len() - 1) as i64))
} else {
None
};
Ok(FileBackedHistory::construct_entry(entry_id, entry))
}
fn load(&self, id: HistoryItemId) -> Result<super::HistoryItem> {
Ok(FileBackedHistory::construct_entry(
Some(id),
self.entries[id.0 as usize].clone(),
))
}
fn count(&self, query: SearchQuery) -> Result<i64> {
Ok(self.search(query)?.len() as i64)
}
fn search(&self, query: SearchQuery) -> Result<Vec<HistoryItem>> {
if query.start_time.is_some() || query.end_time.is_some() {
return Err(ReedlineError(
ReedlineErrorVariants::HistoryFeatureUnsupported {
history: "FileBackedHistory",
feature: "filtering by time",
},
));
}
if query.filter.hostname.is_some()
|| query.filter.cwd_exact.is_some()
|| query.filter.cwd_prefix.is_some()
|| query.filter.exit_successful.is_some()
{
return Err(ReedlineError(
ReedlineErrorVariants::HistoryFeatureUnsupported {
history: "FileBackedHistory",
feature: "filtering by extra info",
},
));
}
let (min_id, max_id) = {
let start = query.start_id.map(|e| e.0);
let end = query.end_id.map(|e| e.0);
if let SearchDirection::Backward = query.direction {
(end, start)
} else {
(start, end)
}
};
let min_id = min_id.map(|e| e + 1).unwrap_or(0);
let max_id = max_id
.map(|e| e - 1)
.unwrap_or(self.entries.len() as i64 - 1);
if max_id < 0 || min_id > self.entries.len() as i64 - 1 {
return Ok(vec![]);
}
let intrinsic_limit = max_id - min_id + 1;
let limit = if let Some(given_limit) = query.limit {
std::cmp::min(intrinsic_limit, given_limit) as usize
} else {
intrinsic_limit as usize
};
let filter = |(idx, cmd): (usize, &String)| {
if !match &query.filter.command_line {
Some(CommandLineSearch::Prefix(p)) => cmd.starts_with(p),
Some(CommandLineSearch::Substring(p)) => cmd.contains(p),
Some(CommandLineSearch::Exact(p)) => cmd == p,
None => true,
} {
return None;
}
if let Some(str) = &query.filter.not_command_line {
if cmd == str {
return None;
}
}
Some(FileBackedHistory::construct_entry(
Some(HistoryItemId::new(idx as i64)),
cmd.to_string(),
))
};
let iter = self
.entries
.iter()
.enumerate()
.skip(min_id as usize)
.take(intrinsic_limit as usize);
if let SearchDirection::Backward = query.direction {
Ok(iter.rev().filter_map(filter).take(limit).collect())
} else {
Ok(iter.filter_map(filter).take(limit).collect())
}
}
fn update(
&mut self,
_id: super::HistoryItemId,
_updater: &dyn Fn(super::HistoryItem) -> super::HistoryItem,
) -> Result<()> {
Err(ReedlineError(
ReedlineErrorVariants::HistoryFeatureUnsupported {
history: "FileBackedHistory",
feature: "updating entries",
},
))
}
fn delete(&mut self, _h: super::HistoryItemId) -> Result<()> {
Err(ReedlineError(
ReedlineErrorVariants::HistoryFeatureUnsupported {
history: "FileBackedHistory",
feature: "removing entries",
},
))
}
fn sync(&mut self) -> std::io::Result<()> {
if let Some(fname) = &self.file {
let own_entries = self.entries.range(self.len_on_disk..);
if let Some(base_dir) = fname.parent() {
std::fs::create_dir_all(base_dir)?;
}
let mut f_lock = fd_lock::RwLock::new(
OpenOptions::new()
.create(true)
.write(true)
.read(true)
.open(fname)?,
);
let mut writer_guard = f_lock.write()?;
let (mut foreign_entries, truncate) = {
let reader = BufReader::new(writer_guard.deref());
let mut from_file = reader
.lines()
.map(|o| o.map(|i| decode_entry(&i)))
.collect::<std::io::Result<VecDeque<_>>>()?;
if from_file.len() + own_entries.len() > self.capacity {
(
from_file.split_off(from_file.len() - (self.capacity - own_entries.len())),
true,
)
} else {
(from_file, false)
}
};
{
let mut writer = BufWriter::new(writer_guard.deref_mut());
if truncate {
writer.seek(SeekFrom::Start(0))?;
for line in &foreign_entries {
writer.write_all(encode_entry(line).as_bytes())?;
writer.write_all("\n".as_bytes())?;
}
} else {
writer.seek(SeekFrom::End(0))?;
}
for line in own_entries {
writer.write_all(encode_entry(line).as_bytes())?;
writer.write_all("\n".as_bytes())?;
}
writer.flush()?;
}
if truncate {
let file = writer_guard.deref_mut();
let file_len = file.stream_position()?;
file.set_len(file_len)?;
}
let own_entries = self.entries.drain(self.len_on_disk..);
foreign_entries.extend(own_entries);
self.entries = foreign_entries;
self.len_on_disk = self.entries.len();
}
Ok(())
}
fn next_session_id(&mut self) -> Result<HistorySessionId> {
Ok(HistorySessionId::new(0))
}
}
impl FileBackedHistory {
pub fn new(capacity: usize) -> Self {
if capacity == usize::MAX {
panic!("History capacity too large to be addressed safely");
}
FileBackedHistory {
capacity,
entries: VecDeque::new(),
file: None,
len_on_disk: 0,
}
}
pub fn with_file(capacity: usize, file: PathBuf) -> std::io::Result<Self> {
let mut hist = Self::new(capacity);
if let Some(base_dir) = file.parent() {
std::fs::create_dir_all(base_dir)?;
}
hist.file = Some(file);
hist.sync()?;
Ok(hist)
}
fn construct_entry(id: Option<HistoryItemId>, command_line: String) -> HistoryItem {
HistoryItem {
id,
start_timestamp: None,
command_line,
session_id: None,
hostname: None,
cwd: None,
duration: None,
exit_status: None,
more_info: None,
}
}
}
impl Drop for FileBackedHistory {
fn drop(&mut self) {
let _res = self.sync();
}
}