system_updater_config/
config_lib_rust_config_lib_source.rs

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use fidl::unpersist;
use fidl_cf_sc_internal_systemupdaterconfig::Config as FidlConfig;
use fuchsia_inspect::Node;
use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
#[derive(Debug)]
pub struct Config {
    pub concurrent_package_resolves: u16,
}
impl Config {
    pub fn take_from_startup_handle() -> Self {
        let config_vmo: zx::Vmo =
            take_startup_handle(HandleInfo::new(HandleType::ComponentConfigVmo, 0))
                .expect("Config VMO handle must be provided and cannot already have been taken.")
                .into();
        let config_size =
            config_vmo.get_content_size().expect("must be able to read config vmo content size");
        assert_ne!(config_size, 0, "config vmo must be non-empty");
        let config_bytes =
            config_vmo.read_to_vec(0, config_size).expect("must be able to read config vmo");
        let checksum_length = u16::from_le_bytes([config_bytes[0], config_bytes[1]]) as usize;
        let fidl_start = 2 + checksum_length;
        let observed_checksum = &config_bytes[2..fidl_start];
        let expected_checksum = vec![
            0x29, 0x13, 0x7c, 0x37, 0xe7, 0x60, 0x88, 0xbb, 0x2b, 0x64, 0x9a, 0xfa, 0xe2, 0xf5,
            0x35, 0xe5, 0x1e, 0x5f, 0x60, 0x49, 0xd7, 0x85, 0xaa, 0x40, 0x84, 0x49, 0xe8, 0x09,
            0xf1, 0xe6, 0x1f, 0x39,
        ];
        assert_eq!(
            observed_checksum, expected_checksum,
            "checksum from config VMO does not match expected checksum"
        );
        let fidl_config: FidlConfig = unpersist(&config_bytes[fidl_start..])
            .expect("must be able to parse bytes as config FIDL");
        Self { concurrent_package_resolves: fidl_config.concurrent_package_resolves }
    }
    pub fn record_inspect(&self, inspector_node: &Node) {
        inspector_node
            .record_uint("concurrent_package_resolves", self.concurrent_package_resolves as u64);
    }
}