Fish importing (#234)

* make a start on fish

* fix

* test

* enable fish

* fmt

* update histpath

set up fish init script

* update readme

* cover edge case

* fmt

* fix session variables

Co-authored-by: PJ <me@panekj.dev>

* respect NOBIND

Co-authored-by: PJ <me@panekj.dev>

* fix env var setting

Co-authored-by: PJ <me@panekj.dev>

* fix whitespace

Co-authored-by: PJ <me@panekj.dev>

* add fish to supported shells

Co-authored-by: PJ <me@panekj.dev>

2 files changed, 222 insertions, 0 deletions

diff --git a/atuin-client/src/import/fish.rs b/atuin-client/src/import/fish.rs
new file mode 100644
index 00000000..4079e122
--- /dev/null
+++ b/atuin-client/src/import/fish.rs
@@ -0,0 +1,221 @@
+// import old shell history!
+// automatically hoover up all that we can find
+
+use std::{
+    fs::File,
+    io::{self, BufRead, BufReader, Read, Seek},
+    path::{Path, PathBuf},
+};
+
+use chrono::prelude::*;
+use chrono::Utc;
+use directories::BaseDirs;
+use eyre::{eyre, Result};
+
+use super::{count_lines, Importer};
+use crate::history::History;
+
+#[derive(Debug)]
+pub struct Fish<R> {
+    file: BufReader<R>,
+    strbuf: String,
+    loc: usize,
+}
+
+impl<R: Read + Seek> Fish<R> {
+    fn new(r: R) -> Result<Self> {
+        let mut buf = BufReader::new(r);
+        let loc = count_lines(&mut buf)?;
+
+        Ok(Self {
+            file: buf,
+            strbuf: String::new(),
+            loc,
+        })
+    }
+}
+
+impl<R: Read> Fish<R> {
+    fn new_entry(&mut self) -> io::Result<bool> {
+        let inner = self.file.fill_buf()?;
+        Ok(inner.starts_with(b"- "))
+    }
+}
+
+impl Importer for Fish<File> {
+    const NAME: &'static str = "fish";
+
+    /// see https://fishshell.com/docs/current/interactive.html#searchable-command-history
+    fn histpath() -> Result<PathBuf> {
+        let base = BaseDirs::new().ok_or_else(|| eyre!("could not determine data directory"))?;
+        let data = base.data_local_dir();
+
+        // fish supports multiple history sessions
+        // If `fish_history` var is missing, or set to `default`, use `fish` as the session
+        let session = std::env::var("fish_history").unwrap_or_else(|_| String::from("fish"));
+        let session = if session == "default" {
+            String::from("fish")
+        } else {
+            session
+        };
+
+        let mut histpath = data.join("fish");
+        histpath.push(format!("{}_history", session));
+
+        if histpath.exists() {
+            Ok(histpath)
+        } else {
+            Err(eyre!("Could not find history file. Try setting $HISTFILE"))
+        }
+    }
+
+    fn parse(path: impl AsRef<Path>) -> Result<Self> {
+        Self::new(File::open(path)?)
+    }
+}
+
+impl<R: Read> Iterator for Fish<R> {
+    type Item = Result<History>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let mut time: Option<DateTime<Utc>> = None;
+        let mut cmd: Option<String> = None;
+
+        loop {
+            self.strbuf.clear();
+            match self.file.read_line(&mut self.strbuf) {
+                // no more content to read
+                Ok(0) => break,
+                // bail on IO error
+                Err(e) => return Some(Err(e.into())),
+                _ => (),
+            }
+
+            // `read_line` adds the line delimeter to the string. No thanks
+            self.strbuf.pop();
+
+            if let Some(c) = self.strbuf.strip_prefix("- cmd: ") {
+                // using raw strings to avoid needing escaping.
+                // replaces double backslashes with single backslashes
+                let c = c.replace(r"\\", r"\");
+                // replaces escaped newlines
+                let c = c.replace(r"\n", "\n");
+                // TODO: any other escape characters?
+
+                cmd = Some(c);
+            } else if let Some(t) = self.strbuf.strip_prefix("  when: ") {
+                // if t is not an int, just ignore this line
+                if let Ok(t) = t.parse::<i64>() {
+                    time = Some(Utc.timestamp(t, 0));
+                }
+            } else {
+                // ... ignore paths lines
+            }
+
+            match self.new_entry() {
+                // next line is a new entry, so let's stop here
+                // only if we have found a command though
+                Ok(true) if cmd.is_some() => break,
+                // bail on IO error
+                Err(e) => return Some(Err(e.into())),
+                _ => (),
+            }
+        }
+
+        let cmd = cmd?;
+        let time = time.unwrap_or_else(Utc::now);
+
+        Some(Ok(History::new(
+            time,
+            cmd,
+            "unknown".into(),
+            -1,
+            -1,
+            None,
+            None,
+        )))
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        // worst case, entry per line
+        (0, Some(self.loc))
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use chrono::{TimeZone, Utc};
+    use std::io::Cursor;
+
+    use super::Fish;
+    use crate::history::History;
+
+    // simple wrapper for fish history entry
+    macro_rules! fishtory {
+        ($timestamp:literal, $command:literal) => {
+            History::new(
+                Utc.timestamp($timestamp, 0),
+                $command.into(),
+                "unknown".into(),
+                -1,
+                -1,
+                None,
+                None,
+            )
+        };
+    }
+
+    #[test]
+    fn parse_complex() {
+        // complicated input with varying contents and escaped strings.
+        let input = r#"- cmd: history --help
+  when: 1639162832
+- cmd: cat ~/.bash_history
+  when: 1639162851
+  paths:
+    - ~/.bash_history
+- cmd: ls ~/.local/share/fish/fish_history
+  when: 1639162890
+  paths:
+    - ~/.local/share/fish/fish_history
+- cmd: cat ~/.local/share/fish/fish_history
+  when: 1639162893
+  paths:
+    - ~/.local/share/fish/fish_history
+ERROR
+- CORRUPTED: ENTRY
+  CONTINUE:
+    - AS
+    - NORMAL
+- cmd: echo "foo" \\\n'bar' baz
+  when: 1639162933
+- cmd: cat ~/.local/share/fish/fish_history
+  when: 1639162939
+  paths:
+    - ~/.local/share/fish/fish_history
+- cmd: echo "\\"" \\\\ "\\\\"
+  when: 1639163063
+- cmd: cat ~/.local/share/fish/fish_history
+  when: 1639163066
+  paths:
+    - ~/.local/share/fish/fish_history
+"#;
+        let cursor = Cursor::new(input);
+        let fish = Fish::new(cursor).unwrap();
+
+        let history = fish.collect::<Result<Vec<_>, _>>().unwrap();
+        assert_eq!(
+            history,
+            vec![
+                fishtory!(1639162832, "history --help"),
+                fishtory!(1639162851, "cat ~/.bash_history"),
+                fishtory!(1639162890, "ls ~/.local/share/fish/fish_history"),
+                fishtory!(1639162893, "cat ~/.local/share/fish/fish_history"),
+                fishtory!(1639162933, "echo \"foo\" \\\n'bar' baz"),
+                fishtory!(1639162939, "cat ~/.local/share/fish/fish_history"),
+                fishtory!(1639163063, r#"echo "\"" \\ "\\""#),
+                fishtory!(1639163066, "cat ~/.local/share/fish/fish_history"),
+            ]
+        );
+    }
+}
diff --git a/atuin-client/src/import/mod.rs b/atuin-client/src/import/mod.rs
index d73d3857..471b7f98 100644
--- a/atuin-client/src/import/mod.rs
+++ b/atuin-client/src/import/mod.rs
@@ -6,6 +6,7 @@ use eyre::Result;
 use crate::history::History;
 
 pub mod bash;
+pub mod fish;
 pub mod resh;
 pub mod zsh;