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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.
*/
//! `aconfig_storage_write_api` is a crate that defines write apis to update flag value
//! in storage file. It provides one api to interface with storage files.
pub mod flag_value_update;
pub mod mapped_file;
#[cfg(test)]
mod test_utils;
use aconfig_storage_file::AconfigStorageError;
use anyhow::anyhow;
use memmap2::MmapMut;
/// Storage file location pb file
pub const STORAGE_LOCATION_FILE: &str = "/metadata/aconfig/persistent_storage_file_records.pb";
/// Get mmaped flag value file given the container name
///
/// \input container: the flag package container
/// \return a result of mapped file
///
///
/// # Safety
///
/// The memory mapped file may have undefined behavior if there are writes to this
/// file not thru this memory mapped file or there are concurrent writes to this
/// memory mapped file. Ensure all writes to the underlying file are thru this memory
/// mapped file and there are no concurrent writes.
pub unsafe fn get_mapped_flag_value_file(container: &str) -> Result<MmapMut, AconfigStorageError> {
unsafe { crate::mapped_file::get_mapped_file(STORAGE_LOCATION_FILE, container) }
}
/// Set boolean flag value thru mapped file and flush the change to file
///
/// \input mapped_file: the mapped flag value file
/// \input offset: flag value offset
/// \input value: updated flag value
/// \return a result of ()
///
pub fn set_boolean_flag_value(
file: &mut MmapMut,
offset: u32,
value: bool,
) -> Result<(), AconfigStorageError> {
crate::flag_value_update::update_boolean_flag_value(file, offset, value)?;
file.flush().map_err(|errmsg| {
AconfigStorageError::MapFlushFail(anyhow!("fail to flush storage file: {}", errmsg))
})
}
// *************************************** //
// CC INTERLOP
// *************************************** //
// Exported rust data structure and methods, c++ code will be generated
#[cxx::bridge]
mod ffi {
// Flag value update return for cc interlop
pub struct BooleanFlagValueUpdateCXX {
pub update_success: bool,
pub error_message: String,
}
// Rust export to c++
extern "Rust" {
pub fn update_boolean_flag_value_cxx(
file: &mut [u8],
offset: u32,
value: bool,
) -> BooleanFlagValueUpdateCXX;
}
}
pub(crate) fn update_boolean_flag_value_cxx(
file: &mut [u8],
offset: u32,
value: bool,
) -> ffi::BooleanFlagValueUpdateCXX {
match crate::flag_value_update::update_boolean_flag_value(file, offset, value) {
Ok(()) => {
ffi::BooleanFlagValueUpdateCXX { update_success: true, error_message: String::from("") }
}
Err(errmsg) => ffi::BooleanFlagValueUpdateCXX {
update_success: false,
error_message: format!("{:?}", errmsg),
},
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::test_utils::copy_to_temp_file;
use aconfig_storage_file::protos::storage_record_pb::write_proto_to_temp_file;
use aconfig_storage_read_api::flag_value_query::find_boolean_flag_value;
use std::fs::File;
use std::io::Read;
fn get_boolean_flag_value_at_offset(file: &str, offset: u32) -> bool {
let mut f = File::open(&file).unwrap();
let mut bytes = Vec::new();
f.read_to_end(&mut bytes).unwrap();
find_boolean_flag_value(&bytes, offset).unwrap()
}
#[test]
fn test_set_boolean_flag_value() {
let flag_value_file = copy_to_temp_file("./tests/flag.val", false).unwrap();
let flag_value_path = flag_value_file.path().display().to_string();
let text_proto = format!(
r#"
files {{
version: 0
container: "system"
package_map: "some_package.map"
flag_map: "some_flag.map"
flag_val: "{}"
timestamp: 12345
}}
"#,
flag_value_path
);
let record_pb_file = write_proto_to_temp_file(&text_proto).unwrap();
let record_pb_path = record_pb_file.path().display().to_string();
// SAFETY:
// The safety here is guaranteed as only this single threaded test process will
// write to this file
unsafe {
let mut file = crate::mapped_file::get_mapped_file(&record_pb_path, "system").unwrap();
for i in 0..8 {
set_boolean_flag_value(&mut file, i, true).unwrap();
let value = get_boolean_flag_value_at_offset(&flag_value_path, i);
assert_eq!(value, true);
set_boolean_flag_value(&mut file, i, false).unwrap();
let value = get_boolean_flag_value_at_offset(&flag_value_path, i);
assert_eq!(value, false);
}
}
}
}
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