element_config/
element_config_rust_config_lib_source.rs

1use fidl::unpersist;
2use fidl_cf_sc_internal_elementconfig::Config as FidlConfig;
3use fuchsia_inspect::{ArrayProperty, Node};
4use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
5use std::convert::TryInto;
6const EXPECTED_CHECKSUM: &[u8] = &[
7    0x3e, 0x91, 0x4b, 0x07, 0x29, 0x7e, 0xb9, 0xa0, 0xd5, 0x82, 0xd9, 0x56, 0xd5, 0x7f, 0x8b, 0x09,
8    0x59, 0xa1, 0x96, 0x43, 0xca, 0x29, 0xfa, 0x1e, 0xfa, 0x55, 0x19, 0x79, 0xdc, 0x4b, 0x57, 0x00,
9];
10#[derive(Debug)]
11pub struct Config {
12    pub default_collection: String,
13    pub url_to_collection: Vec<String>,
14}
15impl Config {
16    #[doc = r" Take the config startup handle and parse its contents."]
17    #[doc = r""]
18    #[doc = r" # Panics"]
19    #[doc = r""]
20    #[doc = r" If the config startup handle was already taken or if it is not valid."]
21    pub fn take_from_startup_handle() -> Self {
22        let handle_info = HandleInfo::new(HandleType::ComponentConfigVmo, 0);
23        let config_vmo: zx::Vmo =
24            take_startup_handle(handle_info).expect("Config VMO handle must be present.").into();
25        Self::from_vmo(&config_vmo).expect("Config VMO handle must be valid.")
26    }
27    #[doc = r" Parse `Self` from `vmo`."]
28    pub fn from_vmo(vmo: &zx::Vmo) -> Result<Self, Error> {
29        let config_size = vmo.get_content_size().map_err(Error::GettingContentSize)?;
30        let config_bytes = vmo.read_to_vec(0, config_size).map_err(Error::ReadingConfigBytes)?;
31        Self::from_bytes(&config_bytes)
32    }
33    #[doc = r" Parse `Self` from `bytes`."]
34    pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
35        let (checksum_len_bytes, bytes) = bytes.split_at_checked(2).ok_or(Error::TooFewBytes)?;
36        let checksum_len_bytes: [u8; 2] =
37            checksum_len_bytes.try_into().expect("previous call guaranteed 2 element slice");
38        let checksum_length = u16::from_le_bytes(checksum_len_bytes) as usize;
39        let (observed_checksum, bytes) =
40            bytes.split_at_checked(checksum_length).ok_or(Error::TooFewBytes)?;
41        if observed_checksum != EXPECTED_CHECKSUM {
42            return Err(Error::ChecksumMismatch { observed_checksum: observed_checksum.to_vec() });
43        }
44        let fidl_config: FidlConfig = unpersist(bytes).map_err(Error::Unpersist)?;
45        Ok(Self {
46            default_collection: fidl_config.default_collection,
47            url_to_collection: fidl_config.url_to_collection,
48        })
49    }
50    pub fn record_inspect(&self, inspector_node: &Node) {
51        inspector_node.record_string("default_collection", &self.default_collection);
52        let arr =
53            inspector_node.create_string_array("url_to_collection", self.url_to_collection.len());
54        for i in 0..self.url_to_collection.len() {
55            arr.set(i, &self.url_to_collection[i]);
56        }
57        inspector_node.record(arr);
58    }
59}
60#[derive(Debug)]
61pub enum Error {
62    #[doc = r" Failed to read the content size of the VMO."]
63    GettingContentSize(zx::Status),
64    #[doc = r" Failed to read the content of the VMO."]
65    ReadingConfigBytes(zx::Status),
66    #[doc = r" The VMO was too small for this config library."]
67    TooFewBytes,
68    #[doc = r" The VMO's config ABI checksum did not match this library's."]
69    ChecksumMismatch { observed_checksum: Vec<u8> },
70    #[doc = r" Failed to parse the non-checksum bytes of the VMO as this library's FIDL type."]
71    Unpersist(fidl::Error),
72}
73impl std::fmt::Display for Error {
74    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
75        match self {
76            Self::GettingContentSize(status) => {
77                write!(f, "Failed to get content size: {status}")
78            }
79            Self::ReadingConfigBytes(status) => {
80                write!(f, "Failed to read VMO content: {status}")
81            }
82            Self::TooFewBytes => {
83                write!(f, "VMO content is not large enough for this config library.")
84            }
85            Self::ChecksumMismatch { observed_checksum } => {
86                write!(
87                    f,
88                    "ABI checksum mismatch, expected {:?}, got {:?}",
89                    EXPECTED_CHECKSUM, observed_checksum,
90                )
91            }
92            Self::Unpersist(fidl_error) => {
93                write!(f, "Failed to parse contents of config VMO: {fidl_error}")
94            }
95        }
96    }
97}
98impl std::error::Error for Error {
99    #[allow(unused_parens, reason = "rustfmt errors without parens here")]
100    fn source(&self) -> Option<(&'_ (dyn std::error::Error + 'static))> {
101        match self {
102            Self::GettingContentSize(ref status) | Self::ReadingConfigBytes(ref status) => {
103                Some(status)
104            }
105            Self::TooFewBytes => None,
106            Self::ChecksumMismatch { .. } => None,
107            Self::Unpersist(ref fidl_error) => Some(fidl_error),
108        }
109    }
110    fn description(&self) -> &str {
111        match self {
112            Self::GettingContentSize(_) => "getting content size",
113            Self::ReadingConfigBytes(_) => "reading VMO contents",
114            Self::TooFewBytes => "VMO contents too small",
115            Self::ChecksumMismatch { .. } => "ABI checksum mismatch",
116            Self::Unpersist(_) => "FIDL parsing error",
117        }
118    }
119}
element_config/element_config_rust_config_lib_source.rs

element_config/
element_config_rust_config_lib_source.rs
