app-info

app-info is a synchronous Rust library for discovering installed desktop applications and extracting file icons on macOS and Windows.

Features

Enumerates application metadata without loading icons by default.
Loads icons lazily or during enumeration at a requested size.
Returns tightly packed RGBA pixels with cheap, reference-counted clones.
Supports best-effort scans with per-entry warnings and strict scans that stop at the first error.
Scans standard macOS application roots recursively.
Scans per-machine and per-user Windows uninstall registry views.
Supports optional Serde serialization through the serde feature.

Installation

[dependencies]
app-info = "0.1"

Enable serialization only when it is needed:

[dependencies]
app-info = { version = "0.1", features = ["serde"] }

Fast metadata-only listing

use app_info::get_installed_apps;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    for app in get_installed_apps(0)? {
        println!("{}: {}", app.name, app.path.display());
    }
    Ok(())
}

Passing 0 keeps enumeration inexpensive because no pixel buffers are created.

Listing with diagnostics

use app_info::{get_installed_apps_with_options, ListOptions};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let options = ListOptions::new().with_icon_size(64)?;
    let report = get_installed_apps_with_options(options)?;

    println!("found {} applications", report.apps.len());
    for warning in report.warnings {
        eprintln!("warning: {}", warning.message);
    }
    Ok(())
}

Use ListOptions::new().strict(true) when inaccessible or malformed entries should fail the complete operation.

Lazy icon loading

use app_info::{find_app_by_name, get_file_icon};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let app = find_app_by_name("Calculator", 0)?;
    let icon = get_file_icon(&app.path, 128)?;
    println!("{}x{}, {} RGBA bytes", icon.width, icon.height, icon.pixels.len());
    Ok(())
}

Icon edges must be between 1 and MAX_ICON_SIZE (currently 2048). This prevents accidental multi-gigabyte allocations.

Name and identifier lookup

find_apps_by_name returns every matching display name.
find_app_by_name is the compatibility helper that returns the first match.
find_app_by_identifier uses the macOS bundle identifier or Windows product code when available.

Saving icons

The example writes application icons to collision-safe PNG filenames:

cargo run --example save_icon

Platform behavior

macOS

The library recursively scans /Applications, /System/Applications, and the current user's ~/Applications directory. Icons are rendered through AppKit in an autorelease pool, with the calling thread's graphics context restored before returning.

Windows

The library scans the Uninstall registry keys under HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER, including 32-bit and 64-bit views on 64-bit builds. It filters common system/update entries, expands environment variables, handles quoted DisplayIcon values and converts Shell icons to RGBA through WIC.

Known limitations

Applications installed outside the standard macOS roots are not discovered.
Microsoft Store/MSIX packages that do not publish uninstall registry entries are not currently enumerated.
Publisher and installation date availability varies by platform and installer.
Some applications do not expose a usable icon or executable path.
The API is synchronous; call it from a worker thread in latency-sensitive UI applications.

License

MIT

app-info 0.1.1