cache_manager_config_lib/
cache_manager_config_lib_rust_config_lib_source.rs

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use fidl::unpersist;
use fidl_cf_sc_internal_cachemanagerconfiglib::Config as FidlConfig;
use fuchsia_inspect::Node;
use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
#[derive(Debug)]
pub struct Config {
    pub cache_clearing_threshold: u64,
    pub storage_checking_frequency: u64,
}
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![
            0xee, 0xc7, 0xc3, 0x22, 0xf2, 0xb0, 0x79, 0x6d, 0x7d, 0x07, 0x77, 0x52, 0x8f, 0x01,
            0x54, 0xa2, 0xaa, 0x69, 0xe1, 0xa9, 0xf1, 0xb7, 0x80, 0xc0, 0xfe, 0x0a, 0xca, 0x3e,
            0xd8, 0xfc, 0x25, 0xd8,
        ];
        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 {
            cache_clearing_threshold: fidl_config.cache_clearing_threshold,
            storage_checking_frequency: fidl_config.storage_checking_frequency,
        }
    }
    pub fn record_inspect(&self, inspector_node: &Node) {
        inspector_node.record_uint("cache_clearing_threshold", self.cache_clearing_threshold);
        inspector_node.record_uint("storage_checking_frequency", self.storage_checking_frequency);
    }
}