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/*
* Copyright (C) 2024 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//! flag value query module defines the flag value file read from mapped bytes
use crate::{AconfigStorageError, FILE_VERSION};
use aconfig_storage_file::{flag_value::FlagValueHeader, read_u8_from_bytes};
use anyhow::anyhow;
/// Query flag value
pub fn find_boolean_flag_value(buf: &[u8], flag_offset: u32) -> Result<bool, AconfigStorageError> {
let interpreted_header = FlagValueHeader::from_bytes(buf)?;
if interpreted_header.version > crate::FILE_VERSION {
return Err(AconfigStorageError::HigherStorageFileVersion(anyhow!(
"Cannot read storage file with a higher version of {} with lib version {}",
interpreted_header.version,
FILE_VERSION
)));
}
let mut head = (interpreted_header.boolean_value_offset + flag_offset) as usize;
// TODO: right now, there is only boolean flags, with more flag value types added
// later, the end of boolean flag value section should be updated (b/322826265).
if head >= interpreted_header.file_size as usize {
return Err(AconfigStorageError::InvalidStorageFileOffset(anyhow!(
"Flag value offset goes beyond the end of the file."
)));
}
let val = read_u8_from_bytes(buf, &mut head)?;
Ok(val == 1)
}
#[cfg(test)]
mod tests {
use super::*;
use aconfig_storage_file::{FlagValueList, StorageFileType};
pub fn create_test_flag_value_list() -> FlagValueList {
let header = FlagValueHeader {
version: crate::FILE_VERSION,
container: String::from("system"),
file_type: StorageFileType::FlagVal as u8,
file_size: 35,
num_flags: 8,
boolean_value_offset: 27,
};
let booleans: Vec<bool> = vec![false, true, false, false, true, true, false, true];
FlagValueList { header, booleans }
}
#[test]
// this test point locks down flag value query
fn test_flag_value_query() {
let flag_value_list = create_test_flag_value_list().as_bytes();
let baseline: Vec<bool> = vec![false, true, false, false, true, true, false, true];
for (offset, expected_value) in baseline.into_iter().enumerate() {
let flag_value = find_boolean_flag_value(&flag_value_list[..], offset as u32).unwrap();
assert_eq!(flag_value, expected_value);
}
}
#[test]
// this test point locks down query beyond the end of boolean section
fn test_boolean_out_of_range() {
let flag_value_list = create_test_flag_value_list().as_bytes();
let error = find_boolean_flag_value(&flag_value_list[..], 8).unwrap_err();
assert_eq!(
format!("{:?}", error),
"InvalidStorageFileOffset(Flag value offset goes beyond the end of the file.)"
);
}
#[test]
// this test point locks down query error when file has a higher version
fn test_higher_version_storage_file() {
let mut value_list = create_test_flag_value_list();
value_list.header.version = crate::FILE_VERSION + 1;
let flag_value = value_list.as_bytes();
let error = find_boolean_flag_value(&flag_value[..], 4).unwrap_err();
assert_eq!(
format!("{:?}", error),
format!(
"HigherStorageFileVersion(Cannot read storage file with a higher version of {} with lib version {})",
crate::FILE_VERSION + 1,
crate::FILE_VERSION
)
);
}
}
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