deepshrink_ffmpeg/
lib.rs

1//! Discovery of the external `ffmpeg`/`ffprobe` binaries.
2//!
3//! Search order (see `docs/PRD/03-tech-stack.md`):
4//! 1. Explicit path from an env var (`DEEPSHRINK_FFMPEG` / `DEEPSHRINK_FFPROBE`).
5//! 2. A binary in `PATH`.
6//! 3. (later) a bundled binary next to the app — for the desktop layer.
7//!
8//! If not found, [`FfmpegError::NotFound`]; the CLI maps this to exit code 3
9//! with an install hint. ffprobe/progress parsing arrives in sessions 002/003.
10#![forbid(unsafe_code)]
11
12use std::ffi::OsString;
13use std::path::PathBuf;
14
15use thiserror::Error;
16
17pub mod caps;
18pub mod probe;
19pub mod progress;
20pub mod run;
21pub mod vmaf;
22
23pub use caps::{has_encoder, has_filter};
24pub use probe::{probe, Ffprobe};
25pub use run::run_pass;
26pub use vmaf::{has_libvmaf, measure_vmaf};
27
28/// Errors from the ffmpeg layer.
29#[derive(Debug, Error)]
30pub enum FfmpegError {
31    #[error(
32        "`{tool}` not found in PATH. Install ffmpeg (macOS: `brew install ffmpeg`) \
33         or point {env} at the binary."
34    )]
35    NotFound {
36        tool: &'static str,
37        env: &'static str,
38    },
39    #[error("failed to spawn `{tool}`: {source}")]
40    Spawn {
41        tool: &'static str,
42        source: std::io::Error,
43    },
44    #[error("`{tool}` exited with {status}:\n{stderr}")]
45    CommandFailed {
46        tool: &'static str,
47        status: String,
48        stderr: String,
49    },
50    #[error("failed to parse ffprobe output: {0}")]
51    Parse(String),
52}
53
54/// The located binaries.
55#[derive(Debug, Clone)]
56pub struct Tools {
57    pub ffmpeg: PathBuf,
58    pub ffprobe: PathBuf,
59}
60
61/// Locate `ffmpeg` and `ffprobe`. Returns the first missing tool as an error.
62pub fn locate() -> Result<Tools, FfmpegError> {
63    Ok(Tools {
64        ffmpeg: locate_one("ffmpeg", "DEEPSHRINK_FFMPEG")?,
65        ffprobe: locate_one("ffprobe", "DEEPSHRINK_FFPROBE")?,
66    })
67}
68
69/// Locate a single tool: first via its env var, then in `PATH`.
70pub fn locate_one(tool: &'static str, env: &'static str) -> Result<PathBuf, FfmpegError> {
71    if let Some(explicit) = std::env::var_os(env) {
72        if !explicit.is_empty() {
73            return Ok(PathBuf::from(explicit));
74        }
75    }
76    which_in_path(tool).ok_or(FfmpegError::NotFound { tool, env })
77}
78
79/// A simple executable lookup in `PATH` (no external dependencies).
80fn which_in_path(tool: &str) -> Option<PathBuf> {
81    let path = std::env::var_os("PATH")?;
82    let names = candidate_names(tool);
83    for dir in std::env::split_paths(&path) {
84        if dir.as_os_str().is_empty() {
85            continue;
86        }
87        for name in &names {
88            let candidate = dir.join(name);
89            if candidate.is_file() {
90                return Some(candidate);
91            }
92        }
93    }
94    None
95}
96
97#[cfg(windows)]
98fn candidate_names(tool: &str) -> Vec<OsString> {
99    // On Windows, account for the common executable extensions.
100    vec![
101        OsString::from(format!("{tool}.exe")),
102        OsString::from(format!("{tool}.bat")),
103        OsString::from(format!("{tool}.cmd")),
104        OsString::from(tool),
105    ]
106}
107
108#[cfg(not(windows))]
109fn candidate_names(tool: &str) -> Vec<OsString> {
110    vec![OsString::from(tool)]
111}
112
113#[cfg(test)]
114mod tests {
115    use super::*;
116
117    #[test]
118    fn missing_binary_is_none() {
119        assert!(which_in_path("deepshrink-definitely-not-a-real-binary-xyz").is_none());
120    }
121
122    #[test]
123    fn candidate_names_include_bare_tool() {
124        let names = candidate_names("ffmpeg");
125        assert!(names.contains(&OsString::from("ffmpeg")));
126    }
127}
deepshrink_ffmpeg/lib.rs

deepshrink_ffmpeg/
lib.rs
