initialHEAD1.0.0no-gods-no-

3 files changed, 1247 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..91eba62
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,360 @@
+use std::ffi::OsString;
+use std::io::Read;
+use std::io::Seek;
+use std::io::Write;
+use std::os::unix::prelude::OsStrExt;
+use std::path::PathBuf;
+use std::process::ExitCode;
+
+use clap::{Parser, Subcommand};
+
+mod shared;
+use shared::{Project, DbCtx};
+
+#[derive(Parser)]
+#[command(version, about, long_about = None)] // , multicall(true))]
+struct Args {
+    #[arg(long)]
+    db: Option<PathBuf>,
+
+    #[command(subcommand)]
+    command: Command,
+}
+
+#[derive(Subcommand)]
+enum Command {
+    /// initialize a qroject database. you should run this first, and shouldn't need to again.
+    Init,
+
+    /// add a project to the qroject database. projects are unique by their name.
+    Add {
+        /// the name of the project.
+        project: String,
+        /// the directory at which the project lives.
+        dir: OsString,
+        /// if the project is on some other computer, the hostname or address of that computer.
+        ///
+        /// with this set, `qg <proj>` will ssh to that computer and switch into that directory.
+        #[arg(long)]
+        host: Option<String>,
+        /// misc additional information about the project. not used by qroject itself.
+        info: Option<String>,
+        /// where the project can be found on the wider internet, if anywhere.
+        ///
+        /// this is mostly useful as notes for homepages, git remotes, etc.
+        upstream: Option<String>,
+    },
+
+    /// forget a project of the given name.
+    ///
+    /// this deletes the database row. this does not make changes to any other files. still, be
+    /// careful.
+    Forget {
+        project: String,
+    },
+
+    /// print the directory for the given project.
+    ///
+    /// this is mostly useful as, for example, `$(q dir foo)` as a stand-in for the actual
+    /// directory of foo.
+    Dir {
+        project: String,
+    },
+
+    /// print information about the given project.
+    Info {
+        project: String,
+    },
+
+    /// print the project's upstream, if any.
+    Upstream {
+        project: String,
+    },
+
+    /// edit `project`'s record.
+    ///
+    /// this opens the project's information in vim (not $EDITOR yet sorry). edits to the project
+    /// are written back to the database (purusant to the unique name restriction). optional fields
+    /// are omitted when null, but can be set by adding a corresponding line in the file.
+    Edit {
+        project: String,
+    },
+
+    /// list all known projects (optionally, with details)
+    List {
+        #[arg(short, default_value_t = false)]
+        verbose: bool,
+    },
+}
+
+enum CliResult {
+    Ok,
+    /// a project-specifying command selected a project that doesn't exist
+    NotAProject,
+    /// a project-specifying command wanted a field that was None
+    NoField,
+    /// a command that involved disk i/o failed to either i or o.
+    IoError,
+    /// something happened related to the database
+    DbError,
+}
+
+impl std::process::Termination for CliResult {
+    fn report(self) -> ExitCode {
+        match self {
+            CliResult::Ok => ExitCode::SUCCESS,
+            CliResult::NotAProject => ExitCode::from(1),
+            CliResult::NoField => ExitCode::from(2),
+            CliResult::IoError => ExitCode::from(3),
+            CliResult::DbError => ExitCode::from(4),
+        }
+    }
+}
+
+unsafe extern "C" {
+    // from libc. no rustix binding..
+    fn mkstemp(template: *mut std::ffi::c_char) -> std::ffi::c_int;
+    fn perror(msg: *const std::ffi::c_char);
+}
+
+fn print_project_name(p: Project) {
+    println!("{}", p.name);
+}
+
+fn print_project(p: Project) {
+    println!("{}", p.name);
+    if p.is_here() {
+        println!("  {: <8}: {}", "path", p.dir.display());
+    } else if let Some(host) = p.host.as_ref() {
+        println!("  {: <8}: {}:{}", "path", host, p.dir.display());
+    } else {
+        println!("  {: <8}: {}:{}", "path", "<unknown>", p.dir.display());
+    }
+    if let Some(info) = p.info.as_ref() {
+        println!("  {: <8}: {}", "info", info);
+    }
+    if let Some(upstream) = p.upstream.as_ref() {
+        println!("  {: <8}: {}", "upstream", upstream);
+    }
+}
+
+fn main() -> CliResult {
+    let args = Args::parse();
+
+    let dbpath = args.db.clone().unwrap_or_else(|| {
+        let mut path = std::env::home_dir().expect("have a homedir");
+        path.push(".config");
+        path.push("qroject");
+        path.push("projects.db");
+        path
+    });
+
+    match process(args, dbpath) {
+        Ok(()) => CliResult::Ok,
+        Err(e) => e,
+    }
+}
+
+fn process(args: Args, dbpath: PathBuf) -> Result<(), CliResult> {
+
+    if let Command::Init = args.command {
+        return DbCtx::init(&dbpath).map_err(|e| {
+            eprintln!("{e}");
+            CliResult::IoError
+        });
+    }
+
+    let conn = DbCtx::new(&dbpath).map_err(|e| {
+        eprintln!("{e}");
+        CliResult::IoError
+    })?;
+
+    match args.command {
+        Command::Init => { Ok(()) /* unreachable */ },
+        Command::Add { project, dir, info, upstream, host } => {
+            conn.project_add(
+                Project {
+                    id: 0,
+                    name: project,
+                    dir,
+                    info,
+                    upstream,
+                    host,
+                }
+            ).map_err(|e| {
+                eprintln!("could not add project: {e}");
+                CliResult::DbError
+            })
+        },
+
+        Command::Forget { project } => {
+            conn.project_forget(
+                &project,
+            ).map_err(|e| {
+                eprintln!("could not forget project: {e}");
+                CliResult::DbError
+            })
+        }
+
+        Command::Dir { project } => {
+            let proj = conn.project_by_name(&project).map_err(|e| {
+                eprintln!("could not look up project: {e}");
+                CliResult::DbError
+            })?;
+            let proj = proj.ok_or(CliResult::NotAProject)?;
+
+            println!("{}", proj.dir.display());
+            Ok(())
+        }
+
+        Command::Info { project } => {
+            let proj = conn.project_by_name(&project).map_err(|e| {
+                eprintln!("could not look up project: {e}");
+                CliResult::DbError
+            })?;
+            let proj = proj.ok_or(CliResult::NotAProject)?;
+
+            print_project(proj);
+            Ok(())
+        }
+
+        Command::Upstream { project } => {
+            let proj = conn.project_by_name(&project).map_err(|e| {
+                eprintln!("could not look up project: {e}");
+                CliResult::DbError
+            })?;
+            let proj = proj.ok_or(CliResult::NotAProject)?;
+            let upstream = proj.upstream.as_ref().ok_or(CliResult::NoField)?;
+
+            println!("{}", upstream);
+            Ok(())
+        }
+
+        Command::Edit { project } => {
+            let proj = conn.project_by_name(&project).map_err(|e| {
+                eprintln!("could not look up project: {e}");
+                CliResult::DbError
+            })?;
+            let mut p = proj.ok_or(CliResult::NotAProject)?;
+
+            let mut existing = String::new();
+            use std::fmt::{Write as FmtWrite};
+            use std::os::fd::FromRawFd;
+            writeln!(existing, "name:{}", p.name)
+                .expect("can write to a string...");
+            writeln!(existing, "dir:{}", p.dir.display())
+                .expect("can write to a string...");
+            if let Some(host) = p.host.as_ref() {
+                writeln!(existing, "host:{}", host)
+                    .expect("can write to a string...");
+            }
+            if let Some(info) = p.info.as_ref() {
+                writeln!(existing, "info:{}", info)
+                    .expect("can write to a string...");
+            }
+            if let Some(upstream) = p.upstream.as_ref() {
+                writeln!(existing, "upstream:{}", upstream)
+                    .expect("can write to a string...");
+            }
+
+            let mut template: [u8; 18] = *b"/tmp/qrojectXXXXXX";
+
+            let tmpfd = unsafe { mkstemp(template.as_mut_ptr() as *mut std::ffi::c_char) };
+
+            if tmpfd == -1 {
+                unsafe { perror(b"mkstemp\0".as_ptr() as *const _); }
+                return Err(CliResult::IoError);
+            }
+
+            let mut file = unsafe { std::fs::File::from_raw_fd(tmpfd) };
+
+            let res = file.write_all(existing.as_bytes());
+            if let Err(e) = res {
+                eprintln!("could not write: {:?}", e);
+                return Err(CliResult::IoError);
+            }
+
+            let res = match std::process::Command::new("vim")
+                .arg(str::from_utf8(&template[..]).expect("valid"))
+                .status() {
+                Ok(res) => res,
+                Err(e) => {
+                    eprintln!("failed to exec editor: {:?}", e);
+                    return Err(CliResult::IoError);
+                }
+            };
+
+            if !res.success() {
+                return Err(CliResult::IoError);
+            }
+
+            let mut edited = String::new();
+            if let Err(_e) = file.rewind() {
+                return Err(CliResult::IoError);
+            }
+            if let Err(_e) = file.read_to_string(&mut edited) {
+                return Err(CliResult::IoError);
+            }
+
+            let lines = edited.split("\n");
+
+            let mut new_name = None;
+            let mut new_dir = None;
+            p.host = None;
+            p.info = None;
+            p.upstream = None;
+
+            for line in lines {
+                if line.trim().is_empty() {
+                    continue;
+                }
+                let Some((field, value)) = line.split_once(":") else {
+                    eprintln!("bogus line: {line}");
+                    return Err(CliResult::IoError);
+                };
+                let value = value.to_owned();
+
+                if field == "name" {
+                    new_name = Some(value);
+                } else if field == "dir" {
+                    new_dir = Some(value);
+                } else if field == "host" {
+                    p.host = Some(value);
+                } else if field == "info" {
+                    p.info = Some(value);
+                } else if field == "upstream" {
+                    p.upstream = Some(value);
+                }
+            }
+
+            let (Some(name), Some(dir)) = (new_name, new_dir) else {
+                eprintln!("missing name or dir");
+                return Err(CliResult::IoError);
+            };
+
+            p.name = name;
+            let dir: &[u8] = dir.as_bytes();
+            let dir: &std::ffi::OsStr = OsStrExt::from_bytes(dir);
+            p.dir = dir.to_os_string();
+
+            conn.project_update(&p)
+                .map_err(|e| {
+                    eprintln!("failed to update project: {}", e);
+                    CliResult::IoError
+                })
+        }
+
+        Command::List { verbose: details } => {
+            let op = if details {
+                print_project
+            } else {
+                print_project_name
+            };
+
+            conn.for_each_project(op).map_err(|e| {
+                eprintln!("could iterate projects: {e}");
+                CliResult::DbError
+            })
+        }
+    }
+}
diff --git a/src/qroject-bash.rs b/src/qroject-bash.rs
new file mode 100644
index 0000000..e54b807
--- /dev/null
+++ b/src/qroject-bash.rs
@@ -0,0 +1,720 @@
+use bash_builtins::{
+    builtin_metadata, Args, Builtin, Error, Result
+};
+
+use std::ffi::{CString, OsStr};
+use std::sync::{Arc, Mutex, OnceLock};
+use std::io::{stdout, stderr, Seek, Read, Write};
+use std::path::PathBuf;
+
+#[cfg(target_family="unix")]
+use std::os::unix::ffi::OsStrExt;
+
+mod shared;
+use shared::{Project, DbCtx};
+
+static QROJECT: OnceLock<Arc<Mutex<core::result::Result<QrojectInner, i32>>>> = OnceLock::new();
+
+struct QrojectGo {
+    inner: Arc<Mutex<core::result::Result<QrojectInner, i32>>>,
+}
+
+struct QrojectInfo {
+    inner: Arc<Mutex<core::result::Result<QrojectInner, i32>>>,
+}
+
+struct QrojectDir {
+    inner: Arc<Mutex<core::result::Result<QrojectInner, i32>>>,
+}
+
+struct Qroject {
+   inner: Arc<Mutex<core::result::Result<QrojectInner, i32>>>
+}
+
+impl QrojectGo {
+    fn new() -> Self {
+        Self {
+            inner: QrojectInner::new(),
+        }
+    }
+}
+
+impl Builtin for QrojectGo {
+    fn call(&mut self, args: &mut Args) -> Result<()> {
+        args.no_options()?;
+        let mut arg_iter = args.raw_arguments();
+        let projname = arg_iter.next()
+            .ok_or(Error::ExitCode(1))?
+            .to_str()
+            .map_err(|_| Error::ExitCode(2))?
+            .to_owned();
+        drop(arg_iter);
+        args.finished()?;
+
+        let mut guard = self.inner.lock().unwrap();
+        let handle = guard.as_mut()
+            .map_err(|c| Error::ExitCode(*c))?;
+
+        handle.op_go(&projname)
+    }
+}
+
+impl QrojectInfo {
+    fn new() -> Self {
+        Self {
+            inner: QrojectInner::new(),
+        }
+    }
+}
+
+impl Builtin for QrojectInfo {
+    fn call(&mut self, args: &mut Args) -> Result<()> {
+        args.no_options()?;
+        let mut arg_iter = args.raw_arguments();
+        let projname = arg_iter.next()
+            .ok_or(Error::ExitCode(1))?
+            .to_str()
+            .map_err(|_| Error::ExitCode(2))?
+            .to_owned();
+        drop(arg_iter);
+        args.finished()?;
+
+        let mut guard = self.inner.lock().unwrap();
+        let handle = guard.as_mut()
+            .map_err(|c| Error::ExitCode(*c))?;
+
+        handle.op_info(&projname)
+    }
+}
+
+impl QrojectDir {
+    fn new() -> Self {
+        Self {
+            inner: QrojectInner::new(),
+        }
+    }
+}
+
+impl Builtin for QrojectDir {
+    fn call(&mut self, args: &mut Args) -> Result<()> {
+        args.no_options()?;
+        let mut arg_iter = args.raw_arguments();
+        let projname = arg_iter.next()
+            .ok_or(Error::ExitCode(1))?
+            .to_str()
+            .map_err(|_| Error::ExitCode(2))?
+            .to_owned();
+        drop(arg_iter);
+        args.finished()?;
+
+        let mut guard = self.inner.lock().unwrap();
+        let handle = guard.as_mut()
+            .map_err(|c| Error::ExitCode(*c))?;
+
+        handle.op_dir(&projname)
+    }
+}
+
+impl Qroject {
+    fn new() -> Self {
+        Self {
+            inner: QrojectInner::new(),
+        }
+    }
+}
+
+unsafe extern "C" {
+    // from libc. no rustix binding..
+    fn mkstemp(template: *mut std::ffi::c_char) -> std::ffi::c_int;
+    fn perror(msg: *const std::ffi::c_char);
+
+    // from bash
+    fn evalstring(
+        cmd: *const std::ffi::c_char,
+        from_file: *const std::ffi::c_char,
+        flags: std::ffi::c_int
+    ) -> std::ffi::c_int;
+    fn set_working_directory(path: *const std::ffi::c_char);
+}
+
+fn project_go_chdir(path: &OsStr) -> Result<()> {
+    // do the same mechanics as `cd` as in bash/builtins/cd.def, ish.
+    // that is:
+    // * `chdir()`,
+    // * then set_working_directory,
+    // * then set OLDPWD and PWD.
+
+    let prev_pwd = bash_builtins::variables::find_as_string("PWD");
+
+    rustix::process::chdir(path).map_err(|e| {
+        let _ = writeln!(stderr(), "chdir fail: {e}");
+        Error::ExitCode(5)
+    })?;
+
+    unsafe {
+        set_working_directory(path.as_bytes().as_ptr() as *const std::ffi::c_char);
+    }
+
+    bash_builtins::variables::set("PWD", path.as_bytes())?;
+    if let Some(prev_pwd) = prev_pwd {
+        bash_builtins::variables::set("OLDPWD", prev_pwd.as_bytes())?;
+    }
+
+    Ok(())
+}
+
+fn project_go_ssh(host: &str, p: Project) -> Result<()> {
+    let command = format!(
+        "ssh {} -t 'cd {}; bash'",
+        host,
+        p.dir.display()
+    );
+    let cstr = CString::new(command).expect("TODO: it's valid though!");
+
+    // from `builtins/common.h`
+    const SEVAL_NOHIST: std::ffi::c_int = 0x004;
+    const SEVAL_NOFREE: std::ffi::c_int = 0x008;
+
+    let res = unsafe {
+        evalstring(
+            cstr.as_bytes().as_ptr() as *const _,
+            std::ptr::null(),
+            SEVAL_NOHIST | SEVAL_NOFREE,
+        )
+    };
+    if res != 0 {
+        let _ = writeln!(stderr(), "could not eval");
+        return Err(Error::ExitCode(2));
+    }
+
+    Ok(())
+}
+
+impl Builtin for Qroject {
+    fn call(&mut self, args: &mut Args) -> Result<()> {
+        args.no_options()?;
+        let mut arg_iter = args.raw_arguments();
+        let command = arg_iter.next()
+            .ok_or(Error::ExitCode(1))?
+            .to_str()
+            .map_err(|_| Error::ExitCode(2))?
+            .to_owned();
+
+        if command == "init" {
+            let path = QrojectInner::dbpath();
+            let Some(path) = path else {
+                let _ = writeln!(stderr(), "no home dir?");
+                return Err(Error::ExitCode(2));
+            };
+
+            return match DbCtx::init(path) {
+                Ok(()) => Ok(()),
+                Err(e) => {
+                    eprintln!("could not init db: {e}");
+                    Err(Error::ExitCode(3))
+                }
+            };
+        }
+
+        let mut guard = self.inner.lock().unwrap();
+        let handle = guard.as_mut()
+            .map_err(|c| Error::ExitCode(*c))?;
+
+        let maybe_projname = arg_iter.next()
+            .map(|arg| match arg.to_str() {
+                Ok(arg) => Ok(arg),
+                Err(e) => {
+                    let _ = writeln!(stderr(), "failed to read project name: {e:?}");
+                    Err(Error::ExitCode(2))
+                }
+            })
+            .transpose()?;
+
+        match command.as_str() {
+            "info" => {
+                let projname = maybe_projname
+                    .ok_or(Error::ExitCode(1))?
+                    .to_owned();
+
+                // TODO: check per-command remaining arglists..
+                drop(arg_iter);
+                args.finished()?;
+                handle.op_info(&projname)
+            }
+            "upstream" => {
+                let projname = maybe_projname
+                    .ok_or(Error::ExitCode(1))?
+                    .to_owned();
+
+                // TODO: check per-command remaining arglists..
+                drop(arg_iter);
+                args.finished()?;
+                handle.op_upstream(&projname)
+            }
+            "go" => {
+                let projname = maybe_projname
+                    .ok_or(Error::ExitCode(1))?
+                    .to_owned();
+
+                // TODO: check per-command remaining arglists..
+                drop(arg_iter);
+                args.finished()?;
+                handle.op_go(&projname)
+            }
+            "dir" => {
+                let projname = maybe_projname
+                    .ok_or(Error::ExitCode(1))?
+                    .to_owned();
+
+                // TODO: check per-command remaining arglists..
+                drop(arg_iter);
+                args.finished()?;
+                handle.op_dir(&projname)
+            }
+            "add" => {
+                let projname = maybe_projname
+                    .ok_or_else(|| {
+                        let _ = writeln!(stderr(), "q add: q add [project] [projdir]");
+                        Error::ExitCode(1)
+                    })?
+                    .to_owned();
+
+                let projdir = arg_iter.next()
+                    .ok_or_else(|| {
+                        let _ = writeln!(stderr(), "q add: q add [project] [projdir]");
+                        Error::ExitCode(1)
+                    })?
+                    .to_str()
+                    .map_err(|_| Error::ExitCode(2))?
+                    .to_owned();
+
+                handle.op_add(&projname, &projdir)
+            }
+            "edit" => {
+                let projname = maybe_projname
+                    .ok_or(Error::ExitCode(1))?
+                    .to_owned();
+
+                handle.op_edit(&projname)
+            }
+            "forget" => {
+                let projname = maybe_projname
+                    .ok_or(Error::ExitCode(1))?
+                    .to_owned();
+
+                handle.op_forget(&projname)
+            }
+            "list" => {
+                let prefix = if let Some(prefix) = maybe_projname {
+                    Some(prefix.to_owned())
+                } else {
+                    None
+                };
+
+                // TODO: check per-command remaining arglists..
+                drop(arg_iter);
+                args.finished()?;
+                handle.op_list(prefix.as_ref().map(|s| s.as_str()))
+            }
+            other => {
+                let _ = writeln!(stderr(), "unknown command: {}", other);
+                Err(Error::ExitCode(127))
+            }
+        }
+    }
+}
+
+struct QrojectInner {
+    // can be None if there's no ~/.config/qroject/
+    db: Option<DbCtx>,
+}
+
+impl QrojectInner {
+    fn dbpath() -> Option<PathBuf> {
+        let home = std::env::home_dir();
+        home.map(|mut homedir| {
+            homedir.push(".config");
+            homedir.push("qroject");
+            homedir.push("projects.db");
+            homedir
+        })
+    }
+
+    fn new() -> Arc<Mutex<core::result::Result<Self, i32>>> {
+        let r = QROJECT.get_or_init(|| {
+            let conn = Self::dbpath().as_ref().map(|p| DbCtx::new(p)).transpose();
+            let inner = match conn {
+                Ok(db) => Ok(QrojectInner { db }),
+                Err(e) => {
+                    eprintln!("{e}");
+                    Err(126)
+                }
+            };
+            Arc::new(Mutex::new(inner))
+        });
+
+        Arc::clone(r)
+    }
+
+    fn op_go(&mut self, projname: &str) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let project = db.project_by_name(&projname)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not find project: {e}");
+                Error::ExitCode(17)
+            })?;
+        let Some(p) = project else {
+            let _ = writeln!(stderr(), "no such project: {}", projname)?;
+            return Err(Error::ExitCode(4));
+        };
+
+        if p.is_here() {
+            project_go_chdir(&p.dir)
+        } else if let Some(host) = p.host.clone().as_ref() {
+            project_go_ssh(host, p)
+        } else {
+            let _ = writeln!(stderr(), "don't know how to get to: {}", projname);
+            return Err(Error::ExitCode(5));
+        }
+    }
+
+    fn op_info(&mut self, projname: &str) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let project = db.project_by_name(&projname)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not find project: {e}");
+                Error::ExitCode(17)
+            })?;
+        let Some(p) = project else {
+            let _ = writeln!(stderr(), "no such project: {}", projname)?;
+            return Err(Error::ExitCode(4));
+        };
+
+        let mut w = stdout();
+        let _ = writeln!(w, "{}", p.name)?;
+        let _ = writeln!(w, "  {: <8}: {}", "path", p.dir.display())?;
+        if let Some(info) = p.info.as_ref() {
+            let _ = writeln!(w, "  {: <8}: {}", "info", info)?;
+        }
+        if let Some(upstream) = p.upstream.as_ref() {
+            let _ = writeln!(w, "  {: <8}: {}", "upstream", upstream)?;
+        }
+
+        Ok(())
+    }
+
+    fn op_upstream(&mut self, projname: &str) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let project = db.project_by_name(&projname)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not find project: {e}");
+                Error::ExitCode(17)
+            })?;
+        let Some(p) = project else {
+            let _ = writeln!(stderr(), "no such project: {}", projname)?;
+            return Err(Error::ExitCode(4));
+        };
+
+        let Some(upstream) = p.upstream.as_ref() else {
+            return Err(Error::ExitCode(1));
+        };
+
+        let mut w = stdout();
+        let _ = writeln!(w, "{}", upstream)?;
+        Ok(())
+    }
+
+    fn op_list(&mut self, prefix: Option<&str>) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let print_project_name = |p: Project| {
+            if let Some(prefix) = prefix {
+                if !p.name.starts_with(prefix) {
+                    return;
+                }
+            }
+
+            let _ = writeln!(stdout(), "{}", p.name);
+        };
+
+        db.for_each_project(print_project_name)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not list projects: {e}");
+                Error::ExitCode(2)
+            })
+    }
+
+    fn op_dir(&mut self, projname: &str) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let project = db.project_by_name(&projname)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not find project: {e}");
+                Error::ExitCode(17)
+            })?;
+        let Some(p) = project else {
+            let _ = writeln!(stderr(), "no such project: {}", projname)?;
+            return Err(Error::ExitCode(4));
+        };
+
+        if let Some(host) = p.host.as_ref() {
+            let _ = writeln!(stderr(), "project is at {}, not local", host)?;
+            return Err(Error::ExitCode(5));
+        }
+
+        let mut w = stdout();
+        let _ = writeln!(w, "{}", p.dir.display())?;
+        Ok(())
+    }
+
+    fn op_forget(&mut self, projname: &str) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        db.project_forget(&projname)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not forget {}: {}", projname, e);
+                Error::ExitCode(2)
+            })?;
+
+        Ok(())
+    }
+
+    fn op_edit(&mut self, projname: &str) -> Result<()> {
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let project = db.project_by_name(&projname)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "could not find project: {e}");
+                Error::ExitCode(17)
+            })?;
+        let Some(mut p) = project else {
+            let _ = writeln!(stderr(), "no such project: {}", projname)?;
+            return Err(Error::ExitCode(4));
+        };
+
+        let mut existing = String::new();
+        use std::fmt::{Write as FmtWrite};
+        use std::os::fd::FromRawFd;
+        writeln!(existing, "name:{}", p.name)
+            .map_err(|_| Error::ExitCode(5))?;
+        writeln!(existing, "dir:{}", p.dir.display())
+            .map_err(|_| Error::ExitCode(5))?;
+        if let Some(host) = p.host.as_ref() {
+            writeln!(existing, "host:{}", host)
+                .map_err(|_| Error::ExitCode(5))?;
+        }
+        if let Some(info) = p.info.as_ref() {
+            writeln!(existing, "info:{}", info)
+                .map_err(|_| Error::ExitCode(5))?;
+        }
+        if let Some(upstream) = p.upstream.as_ref() {
+            writeln!(existing, "upstream:{}", upstream)
+                .map_err(|_| Error::ExitCode(5))?;
+        }
+
+        let mut template: [u8; 18] = *b"/tmp/qrojectXXXXXX";
+
+        let tmpfd = unsafe { mkstemp(template.as_mut_ptr() as *mut std::ffi::c_char) };
+
+        if tmpfd == -1 {
+            unsafe { perror(b"mkstemp\0".as_ptr() as *const _); }
+            return Err(Error::ExitCode(5));
+        }
+
+        let mut file = unsafe { std::fs::File::from_raw_fd(tmpfd) };
+
+        let res = file.write_all(existing.as_bytes());
+        if let Err(e) = res {
+            writeln!(stderr(), "could not write: {:?}", e)?;
+            return Err(Error::ExitCode(6));
+        }
+
+        let command = format!(
+            "vim {}",
+            str::from_utf8(&template[..]).expect("valid")
+        );
+        let cstr = CString::new(command).expect("TODO: it's valid though!");
+
+        // from `builtins/common.h`
+        const SEVAL_NOHIST: std::ffi::c_int = 0x004;
+        const SEVAL_NOFREE: std::ffi::c_int = 0x008;
+
+        let res = unsafe {
+            evalstring(
+                cstr.as_bytes().as_ptr() as *const _,
+                std::ptr::null(),
+                SEVAL_NOHIST | SEVAL_NOFREE,
+            )
+        };
+        if res != 0 {
+            let _ = writeln!(stderr(), "could not eval");
+            return Err(Error::ExitCode(2));
+        }
+
+        let mut edited = String::new();
+        file.rewind()
+            .map_err(|_e| Error::ExitCode(5))?;
+        file.read_to_string(&mut edited)
+            .map_err(|_e| Error::ExitCode(5))?;
+
+        let lines = edited.split("\n");
+
+        let mut new_name = None;
+        let mut new_dir = None;
+        p.host = None;
+        p.info = None;
+        p.upstream = None;
+
+        for line in lines {
+            if line.trim().is_empty() {
+                continue;
+            }
+            let Some((field, value)) = line.split_once(":") else {
+                writeln!(stderr(), "bogus line: {line}")?;
+                return Err(Error::ExitCode(7));
+            };
+            let value = value.to_owned();
+
+            if field == "name" {
+                new_name = Some(value);
+            } else if field == "dir" {
+                new_dir = Some(value);
+            } else if field == "host" {
+                p.host = Some(value);
+            } else if field == "info" {
+                p.info = Some(value);
+            } else if field == "upstream" {
+                p.upstream = Some(value);
+            }
+        }
+
+        let (Some(name), Some(dir)) = (new_name, new_dir) else {
+            writeln!(stderr(), "missing name or dir")?;
+            return Err(Error::ExitCode(8));
+        };
+
+        p.name = name;
+        let dir: &[u8] = dir.as_bytes();
+        let dir: &std::ffi::OsStr = OsStrExt::from_bytes(dir);
+        p.dir = dir.to_os_string();
+
+        db.project_update(&p)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "failed to update project: {}", e);
+                Error::ExitCode(9)
+            })?;
+
+        std::fs::remove_file(OsStr::from_bytes(&template))
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "couldn't unlink tempfile? {}", e);
+                Error::ExitCode(10)
+            })?;
+
+        Ok(())
+    }
+
+    fn op_add(&mut self, projname: &str, projdir: &str) -> Result<()> {
+        let abspath = std::path::absolute(projdir)
+            .map_err(|_| Error::ExitCode(8))?;
+
+        let Some(db) = self.db.as_ref() else {
+            return Err(Error::ExitCode(16));
+        };
+
+        let new = Project {
+            id: 0,
+            name: projname.to_string(),
+            dir: abspath.into_os_string(),
+            info: None,
+            upstream: None,
+            host: None,
+        };
+        db.project_add(new)
+            .map_err(|e| {
+                let _ = writeln!(stderr(), "failed to add project: {}", e);
+                Error::ExitCode(9)
+            })?;
+        Ok(())
+    }
+}
+
+builtin_metadata!(
+    name = "q",
+    create = Qroject::new,
+    short_doc = "q {add,go,edit,dir,forget, upstream,info,list} [project]",
+    long_doc = "project switcher.\n\
+    \n\
+    switch to, edit, or print information about, a project. all operations\n\
+    are either shell built-ins of their own (qg, qi, qd), or subcommands\n\
+    of this program, \"q\".\n\
+    \n\
+    COMMANDS:\n\
+    \n  \
+      add [projname] [projdir]: add a project named \"projname\" at \n      \
+          \"projdir\" to the project database. if this project should \n      \
+          have additional fields (like info, upstream, ..) it can be edited\n      \
+          after adding.\n  \
+      go [projname]: change directory to \"projname\".\n  \
+      edit [projname]: edit a project definition in vim (not $EDITOR yet, sorry)\n  \
+      dir [projname]: print the directory for \"projname\"\n  \
+      upstream [projname]: print the upstream for \"projname\"\n  \
+      info [projname]: print all info for \"projname\"\n  \
+      forget [projname]: forget about \"projname\". this deletes the row\n      \
+          from the database, does not change any other files. still, be careful.\n  \
+      list [prefix]: list projects, optionally restricting print all info for \"projname\"\n\
+    ",
+);
+
+builtin_metadata!(
+    name = "qg",
+    create = QrojectGo::new,
+    short_doc = "qg [project]",
+    long_doc = "go to [project]",
+);
+
+builtin_metadata!(
+    name = "qi",
+    create = QrojectInfo::new,
+    short_doc = "qi [project]",
+    long_doc = "info for [project]",
+);
+
+builtin_metadata!(
+    name = "qd",
+    create = QrojectDir::new,
+    short_doc = "qd [project]",
+    long_doc = "print directory for [project], if local",
+);
+
+// this is probably the kind of software that, circa 2026, you'd ask an LLM to cough up.
+// probably would do an ok job of it too, even. see `shoutouts` in the readme for a sense of why i
+// didn't. someone put in the work for `bash_builtins`, complete with rather nice docs! i
+// appreciate that! in the spirit of collaboration, i wanted to build on that.
+//
+// stamping out a few thousand lines of emdashful code would not have known about "related
+// bindings". try it if you want. there's no love of the game in it. fully spiritless. it's very
+// easy to simply Not Care about our peers and neighbors in open source. don't do that. it's
+// important to exist, and we only exist if we see each other.
+//
+// i had fun learning how to put this together and hope you have a bit of fun reading this too. or
+// maybe it's just useful, and you never read this; that's ok too.
+//
+// it's wartful, because of course it is, because *i* coughed this up in basically a day.
+// hope you appreciate those too.
diff --git a/src/shared.rs b/src/shared.rs
new file mode 100644
index 0000000..bbca537
--- /dev/null
+++ b/src/shared.rs
@@ -0,0 +1,167 @@
+use std::ffi::{OsStr, OsString};
+#[cfg(target_family="unix")]
+use std::os::unix::ffi::OsStrExt;
+#[cfg(target_family="windows")]
+use std::os::windows::ffi::OsStrExt;
+use std::sync::Mutex;
+use std::path::Path;
+
+use rusqlite::{Connection, params};
+
+// in some configurations (`main.rs`), nothing actually uses id.
+#[allow(dead_code)]
+pub struct Project {
+    pub id: u32,
+    pub name: String,
+    pub dir: OsString,
+    pub host: Option<String>,
+    pub info: Option<String>,
+    pub upstream: Option<String>,
+}
+
+impl Project {
+    pub fn is_here(&self) -> bool {
+        let uname = rustix::system::uname();
+        let me = uname.nodename();
+        if let Some(host) = self.host.as_ref() {
+            host.as_bytes() == me.to_bytes()
+        } else {
+            std::path::Path::new(&self.dir).exists()
+        }
+    }
+}
+
+pub struct DbCtx {
+    pub conn: Mutex<Connection>,
+}
+
+impl DbCtx {
+    pub fn new<P: AsRef<Path>>(db_path: P) -> Result<Self, String> {
+        let conn = Connection::open(db_path)
+            .map_err(|e| format!("failed to open db: {e}"))?;
+
+        Ok(Self {
+            conn: Mutex::new(conn)
+        })
+    }
+
+    pub fn init<P: AsRef<Path>>(db_path: P) -> Result<(), String> {
+        let conn = Connection::open(db_path)
+            .map_err(|e| format!("failed to open db: {e}"))?;
+
+        conn.execute(
+            "CREATE TABLE projects (\
+              id INTEGER PRIMARY KEY AUTOINCREMENT, \
+              name TEXT UNIQUE NOT NULL, \
+              dir BLOB NOT NULL, \
+              host TEXT, \
+              info TEXT, \
+              upstream TEXT\
+            );", params![])
+            .map_err(|e| format!("failed to create projects table: {e}"))?;
+
+        conn.execute(
+            "CREATE INDEX projname on projects(name);", params![])
+            .map_err(|e| format!("failed to create index?!: {e}"))?;
+
+        Ok(())
+    }
+
+    pub fn project_add(&self, p: Project) -> Result<(), String> {
+        let conn = self.conn.lock().unwrap();
+        conn
+            .execute(
+                "insert into projects \
+                    (name, dir, host, info, upstream) \
+                    values (?1, ?2, ?3, ?4, ?5);",/* \
+                    on conflict (name) do update \
+                        set dir=excluded.dir \
+                            info=excluded.info \
+                            upstream=excluded.upstream;",*/
+                params![p.name, p.dir.as_os_str().as_bytes(), p.host, p.info, p.upstream]
+            )
+            .map_err(|e| format!("failed to insert project: {e}"))?;
+        Ok(())
+    }
+
+    pub fn project_update(&self, p: &Project) -> Result<(), String> {
+        let conn = self.conn.lock().unwrap();
+        // TODO: don't panic on name conflict..
+        conn
+            .execute(
+                "update projects \
+                    set name=?2, \
+                        dir=?3, \
+                        host=?4, \
+                        info=?5, \
+                        upstream=?6 \
+                    where id=?1",
+                params![p.id.to_string(), p.name, p.dir.as_os_str().as_bytes(), p.host, p.info, p.upstream]
+            )
+            .map_err(|e| format!("failed to update project: {e}"))?;
+        Ok(())
+    }
+
+    pub fn project_forget(&self, name: &str) -> Result<(), String> {
+        let conn = self.conn.lock().unwrap();
+        conn
+            .execute(
+                "delete from projects where name=?1;",
+                params![name]
+            )
+            .map_err(|e| format!("failed to delete project: {e}"))?;
+        Ok(())
+    }
+
+    pub fn for_each_project(&self, op: impl Fn(Project)) -> Result<(), String> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt = conn.prepare("select * from projects").expect("can prepare");
+        let mut rows = stmt.query([])
+            .map_err(|e| format!("failed to select projects: {e}"))?;
+
+        while let Some(row) = rows.next().expect("can read row") {
+            let id: u32 = row.get(0).expect("typecheck");
+            let dir: Box<[u8]> = row.get(2).expect("typecheck");
+            let osstr: &OsStr = OsStrExt::from_bytes(&dir);
+            let project = Project {
+                id,
+                name: row.get(1).expect("typecheck"),
+                dir: osstr.to_os_string(),
+                host: row.get(3).expect("typecheck"),
+                info: row.get(4).expect("typecheck"),
+                upstream: row.get(5).expect("typecheck"),
+            };
+
+            op(project);
+        }
+        Ok(())
+    }
+
+    pub fn project_by_name(&self, name: &str) -> Result<Option<Project>, String> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt = conn.prepare("select id, name, dir, host, info, upstream from projects where name=?1")
+            .expect("can prepare");
+        let mut rows = stmt.query([name])
+            .map_err(|e| format!("failed to find projects: {e}"))?;
+
+        let project = if let Some(row) = rows.next().expect("can read row") {
+            let id: u32 = row.get(0).expect("typecheck");
+            let dir: Box<[u8]> = row.get(2).expect("typecheck");
+            let osstr: &OsStr = OsStrExt::from_bytes(&dir);
+            Some(Project {
+                id,
+                name: row.get(1).expect("typecheck"),
+                dir: osstr.to_os_string(),
+                host: row.get(3).expect("typecheck"),
+                info: row.get(4).expect("typecheck"),
+                upstream: row.get(5).expect("typecheck"),
+            })
+        } else {
+            None
+        };
+
+        assert!(rows.next().expect("can try getting next row").is_none());
+
+        Ok(project)
+    }
+}