kimun_notes/update/
channel.rs

1//! Install-channel detection. Decides whether this binary may self-update or
2//! must defer to a package manager. Detection that is ambiguous or fails is
3//! treated as notify-only: the conservative default never risks corrupting a
4//! managed install.
5//!
6//! Order of precedence:
7//!   1. The install marker (`install.toml`) written by `install.sh` — deterministic.
8//!   2. A heuristic on the canonicalised executable path.
9//!
10//! Anything that cannot be classified fails safe to notify-only.
11
12use std::env;
13use std::path::Path;
14use std::sync::OnceLock;
15
16const MARKER_FILE: &str = "install.toml";
17
18#[derive(Debug, Clone, Copy, PartialEq, Eq)]
19pub enum InstallChannel {
20    /// Installed via the official `install.sh`.
21    Script,
22    /// A manually downloaded release archive.
23    Direct,
24    /// Homebrew tap — package-manager owned, notify-only.
25    Brew,
26    /// `cargo install` — package-manager owned, notify-only.
27    Cargo,
28    /// Could not determine; treated as notify-only.
29    Unknown,
30}
31
32impl InstallChannel {
33    /// Whether kimün may replace its own binary on this channel.
34    pub fn self_update_eligible(self) -> bool {
35        matches!(self, Self::Script | Self::Direct)
36    }
37
38    /// The command a user should run to upgrade on a package-manager channel,
39    /// or `None` where self-update applies (or the channel is unknown).
40    pub fn upgrade_hint(self) -> Option<&'static str> {
41        match self {
42            Self::Brew => Some("brew upgrade kimun"),
43            Self::Cargo => Some("cargo install kimun-notes"),
44            _ => None,
45        }
46    }
47}
48
49#[derive(serde::Deserialize)]
50struct InstallMarker {
51    channel: String,
52}
53
54/// Detect how the running binary was installed. `config_dir` is kimün's config
55/// directory (where `install.sh` writes the marker).
56///
57/// The marker (cheap file read, depends on `config_dir`) is consulted first.
58/// The fallback path heuristic — `current_exe` canonicalisation plus a
59/// filesystem writability probe — is the expensive part and is invariant for
60/// the process, so only *it* is cached. Caching keyed on the result of an
61/// argument would let the first caller's `config_dir` win forever.
62pub fn detect(config_dir: &Path) -> InstallChannel {
63    if let Some(channel) = channel_from_marker(config_dir) {
64        return channel;
65    }
66    static EXE_CHANNEL: OnceLock<InstallChannel> = OnceLock::new();
67    *EXE_CHANNEL.get_or_init(channel_from_exe_path)
68}
69
70fn channel_from_marker(config_dir: &Path) -> Option<InstallChannel> {
71    let raw = std::fs::read_to_string(config_dir.join(MARKER_FILE)).ok()?;
72    let marker: InstallMarker = toml::from_str(&raw).ok()?;
73    match marker.channel.as_str() {
74        "script" => Some(InstallChannel::Script),
75        "direct" => Some(InstallChannel::Direct),
76        "brew" => Some(InstallChannel::Brew),
77        "cargo" => Some(InstallChannel::Cargo),
78        _ => None,
79    }
80}
81
82fn channel_from_exe_path() -> InstallChannel {
83    let exe = match env::current_exe().and_then(|p| p.canonicalize()) {
84        Ok(p) => p,
85        // No idea where we live — do not risk touching a managed binary.
86        Err(_) => return InstallChannel::Unknown,
87    };
88    let path = exe.to_string_lossy();
89
90    // Homebrew: an explicit prefix env var, or the Cellar layout the formula
91    // installs into (current_exe is canonicalised, so brew's bin symlink is
92    // already resolved into the Cellar path).
93    if let Ok(prefix) = env::var("HOMEBREW_PREFIX")
94        && !prefix.is_empty()
95        && path.starts_with(prefix.as_str())
96    {
97        return InstallChannel::Brew;
98    }
99    if path.contains("/Cellar/") || path.contains("/homebrew/") {
100        return InstallChannel::Brew;
101    }
102
103    // cargo install: under CARGO_HOME/bin or ~/.cargo/bin.
104    if let Ok(cargo_home) = env::var("CARGO_HOME")
105        && !cargo_home.is_empty()
106        && exe.starts_with(&cargo_home)
107    {
108        return InstallChannel::Cargo;
109    }
110    if let Ok(home) = crate::settings::get_home_dir()
111        && exe.starts_with(home.join(".cargo").join("bin"))
112    {
113        return InstallChannel::Cargo;
114    }
115
116    // Otherwise the user placed this binary themselves. Only call it
117    // self-update eligible if its directory is actually writable: a binary in a
118    // root-owned/system location (e.g. /usr/bin, a distro package, the Nix
119    // store) must stay notify-only and never be overwritten in place, even
120    // though it is neither brew nor cargo.
121    match exe.parent() {
122        Some(dir) if dir_is_writable(dir) => InstallChannel::Direct,
123        _ => InstallChannel::Unknown,
124    }
125}
126
127/// Whether a probe file can be created in `dir` (i.e. the current user may
128/// write there). Cleans up the probe. A best-effort check used only to gate
129/// self-update eligibility; on any error it returns false (fail safe).
130fn dir_is_writable(dir: &Path) -> bool {
131    let probe = dir.join(format!(".kimun-write-probe-{}", std::process::id()));
132    match std::fs::File::create(&probe) {
133        Ok(_) => {
134            let _ = std::fs::remove_file(&probe);
135            true
136        }
137        Err(_) => false,
138    }
139}
kimun_notes/update/channel.rs

kimun_notes/update/
channel.rs
