example_config/
example_config_rust_config_lib_source.rs

1use fidl::unpersist;
2use fidl_cf_sc_internal_exampleconfig::Config as FidlConfig;
3use fuchsia_inspect::Node;
4use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
5use std::convert::TryInto;
6const EXPECTED_CHECKSUM: &[u8] = &[
7    0xff, 0x80, 0x66, 0xec, 0x7f, 0x4b, 0xf7, 0x3e, 0xa2, 0xa7, 0xce, 0xae, 0xaa, 0x11, 0x41, 0x73,
8    0xee, 0x0f, 0x44, 0xb1, 0x7d, 0x61, 0xca, 0xcd, 0xd3, 0x76, 0x77, 0x90, 0xc5, 0x1e, 0x6d, 0xbf,
9];
10#[derive(Debug)]
11pub struct Config {
12    pub greeting: String,
13}
14impl Config {
15    #[doc = r" Take the config startup handle and parse its contents."]
16    #[doc = r""]
17    #[doc = r" # Panics"]
18    #[doc = r""]
19    #[doc = r" If the config startup handle was already taken or if it is not valid."]
20    pub fn take_from_startup_handle() -> Self {
21        let handle_info = HandleInfo::new(HandleType::ComponentConfigVmo, 0);
22        let config_vmo: zx::Vmo =
23            take_startup_handle(handle_info).expect("Config VMO handle must be present.").into();
24        Self::from_vmo(&config_vmo).expect("Config VMO handle must be valid.")
25    }
26    #[doc = r" Parse `Self` from `vmo`."]
27    pub fn from_vmo(vmo: &zx::Vmo) -> Result<Self, Error> {
28        let config_size = vmo.get_content_size().map_err(Error::GettingContentSize)?;
29        let config_bytes = vmo.read_to_vec(0, config_size).map_err(Error::ReadingConfigBytes)?;
30        Self::from_bytes(&config_bytes)
31    }
32    #[doc = r" Parse `Self` from `bytes`."]
33    pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
34        let (checksum_len_bytes, bytes) = bytes.split_at_checked(2).ok_or(Error::TooFewBytes)?;
35        let checksum_len_bytes: [u8; 2] =
36            checksum_len_bytes.try_into().expect("previous call guaranteed 2 element slice");
37        let checksum_length = u16::from_le_bytes(checksum_len_bytes) as usize;
38        let (observed_checksum, bytes) =
39            bytes.split_at_checked(checksum_length).ok_or(Error::TooFewBytes)?;
40        if observed_checksum != EXPECTED_CHECKSUM {
41            return Err(Error::ChecksumMismatch { observed_checksum: observed_checksum.to_vec() });
42        }
43        let fidl_config: FidlConfig = unpersist(bytes).map_err(Error::Unpersist)?;
44        Ok(Self { greeting: fidl_config.greeting })
45    }
46    pub fn record_inspect(&self, inspector_node: &Node) {
47        inspector_node.record_string("greeting", &self.greeting);
48    }
49}
50#[derive(Debug)]
51pub enum Error {
52    #[doc = r" Failed to read the content size of the VMO."]
53    GettingContentSize(zx::Status),
54    #[doc = r" Failed to read the content of the VMO."]
55    ReadingConfigBytes(zx::Status),
56    #[doc = r" The VMO was too small for this config library."]
57    TooFewBytes,
58    #[doc = r" The VMO's config ABI checksum did not match this library's."]
59    ChecksumMismatch { observed_checksum: Vec<u8> },
60    #[doc = r" Failed to parse the non-checksum bytes of the VMO as this library's FIDL type."]
61    Unpersist(fidl::Error),
62}
63impl std::fmt::Display for Error {
64    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
65        match self {
66            Self::GettingContentSize(status) => {
67                write!(f, "Failed to get content size: {status}")
68            }
69            Self::ReadingConfigBytes(status) => {
70                write!(f, "Failed to read VMO content: {status}")
71            }
72            Self::TooFewBytes => {
73                write!(f, "VMO content is not large enough for this config library.")
74            }
75            Self::ChecksumMismatch { observed_checksum } => {
76                write!(
77                    f,
78                    "ABI checksum mismatch, expected {:?}, got {:?}",
79                    EXPECTED_CHECKSUM, observed_checksum,
80                )
81            }
82            Self::Unpersist(fidl_error) => {
83                write!(f, "Failed to parse contents of config VMO: {fidl_error}")
84            }
85        }
86    }
87}
88impl std::error::Error for Error {
89    #[allow(unused_parens, reason = "rustfmt errors without parens here")]
90    fn source(&self) -> Option<(&'_ (dyn std::error::Error + 'static))> {
91        match self {
92            Self::GettingContentSize(ref status) | Self::ReadingConfigBytes(ref status) => {
93                Some(status)
94            }
95            Self::TooFewBytes => None,
96            Self::ChecksumMismatch { .. } => None,
97            Self::Unpersist(ref fidl_error) => Some(fidl_error),
98        }
99    }
100    fn description(&self) -> &str {
101        match self {
102            Self::GettingContentSize(_) => "getting content size",
103            Self::ReadingConfigBytes(_) => "reading VMO contents",
104            Self::TooFewBytes => "VMO contents too small",
105            Self::ChecksumMismatch { .. } => "ABI checksum mismatch",
106            Self::Unpersist(_) => "FIDL parsing error",
107        }
108    }
109}
example_config/example_config_rust_config_lib_source.rs

example_config/
example_config_rust_config_lib_source.rs
