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Commit 3e83375d authored by Dennis Shen's avatar Dennis Shen Committed by Automerger Merge Worker
Browse files

Merge "aconfig: create package table query public function" into main am: 043a1eec

parents 3e7671fd 043a1eec
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+110 −9
Original line number Diff line number Diff line
@@ -17,8 +17,8 @@
//! package table module defines the package table file format and methods for serialization
//! and deserialization

use crate::{read_str_from_bytes, read_u32_from_bytes};
use anyhow::Result;
use crate::{get_bucket_index, read_str_from_bytes, read_u32_from_bytes};
use anyhow::{anyhow, Result};

/// Package table header struct
#[derive(PartialEq, Debug)]
@@ -86,9 +86,9 @@ impl PackageTableNode {
    }

    /// Deserialize from bytes
    pub fn from_bytes(bytes: &[u8], num_buckets: u32) -> Result<Self> {
    pub fn from_bytes(bytes: &[u8]) -> Result<Self> {
        let mut head = 0;
        let mut node = Self {
        let node = Self {
            package_name: read_str_from_bytes(bytes, &mut head)?,
            package_id: read_u32_from_bytes(bytes, &mut head)?,
            boolean_offset: read_u32_from_bytes(bytes, &mut head)?,
@@ -98,7 +98,6 @@ impl PackageTableNode {
            },
            bucket_index: 0,
        };
        node.bucket_index = crate::get_bucket_index(&node.package_name, num_buckets);
        Ok(node)
    }
}
@@ -136,8 +135,9 @@ impl PackageTable {
            .collect();
        let nodes = (0..num_packages)
            .map(|_| {
                let node = PackageTableNode::from_bytes(&bytes[head..], num_buckets).unwrap();
                let mut node = PackageTableNode::from_bytes(&bytes[head..]).unwrap();
                head += node.as_bytes().len();
                node.bucket_index = get_bucket_index(&node.package_name, num_buckets);
                node
            })
            .collect();
@@ -147,6 +147,50 @@ impl PackageTable {
    }
}

/// Package table query return
#[derive(PartialEq, Debug)]
pub struct PackageOffset {
    pub package_id: u32,
    pub boolean_offset: u32,
}

/// Query package id and start offset
pub fn find_package_offset(buf: &[u8], package: &str) -> Result<Option<PackageOffset>> {
    let interpreted_header = PackageTableHeader::from_bytes(buf)?;
    if interpreted_header.version > crate::FILE_VERSION {
        return Err(anyhow!(
            "Cannot read storage file with a higher version of {} with lib version {}",
            interpreted_header.version,
            crate::FILE_VERSION
        ));
    }

    let num_buckets = (interpreted_header.node_offset - interpreted_header.bucket_offset) / 4;
    let bucket_index = get_bucket_index(&package, num_buckets);

    let mut pos = (interpreted_header.bucket_offset + 4 * bucket_index) as usize;
    let mut package_node_offset = read_u32_from_bytes(buf, &mut pos)? as usize;
    if package_node_offset < interpreted_header.node_offset as usize
        || package_node_offset >= interpreted_header.file_size as usize
    {
        return Ok(None);
    }

    loop {
        let interpreted_node = PackageTableNode::from_bytes(&buf[package_node_offset..])?;
        if interpreted_node.package_name == package {
            return Ok(Some(PackageOffset {
                package_id: interpreted_node.package_id,
                boolean_offset: interpreted_node.boolean_offset,
            }));
        }
        match interpreted_node.next_offset {
            Some(offset) => package_node_offset = offset as usize,
            None => return Ok(None),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
@@ -199,13 +243,70 @@ mod tests {
        let nodes: &Vec<PackageTableNode> = &package_table.nodes;
        let num_buckets = crate::get_table_size(header.num_packages).unwrap();
        for node in nodes.iter() {
            let reinterpreted_node = PackageTableNode::from_bytes(&node.as_bytes(), num_buckets);
            assert!(reinterpreted_node.is_ok());
            assert_eq!(node, &reinterpreted_node.unwrap());
            let mut reinterpreted_node = PackageTableNode::from_bytes(&node.as_bytes()).unwrap();
            reinterpreted_node.bucket_index =
                get_bucket_index(&reinterpreted_node.package_name, num_buckets);
            assert_eq!(node, &reinterpreted_node);
        }

        let reinterpreted_table = PackageTable::from_bytes(&package_table.as_bytes());
        assert!(reinterpreted_table.is_ok());
        assert_eq!(&package_table, &reinterpreted_table.unwrap());
    }

    #[test]
    // this test point locks down table query
    fn test_package_query() {
        let package_table = create_test_package_table().unwrap().as_bytes();
        let package_offset =
            find_package_offset(&package_table[..], "com.android.aconfig.storage.test_1")
                .unwrap()
                .unwrap();
        let expected_package_offset = PackageOffset { package_id: 0, boolean_offset: 0 };
        assert_eq!(package_offset, expected_package_offset);
        let package_offset =
            find_package_offset(&package_table[..], "com.android.aconfig.storage.test_2")
                .unwrap()
                .unwrap();
        let expected_package_offset = PackageOffset { package_id: 1, boolean_offset: 3 };
        assert_eq!(package_offset, expected_package_offset);
        let package_offset =
            find_package_offset(&package_table[..], "com.android.aconfig.storage.test_4")
                .unwrap()
                .unwrap();
        let expected_package_offset = PackageOffset { package_id: 2, boolean_offset: 6 };
        assert_eq!(package_offset, expected_package_offset);
    }

    #[test]
    // this test point locks down table query of a non exist package
    fn test_not_existed_package_query() {
        // this will land at an empty bucket
        let package_table = create_test_package_table().unwrap().as_bytes();
        let package_offset =
            find_package_offset(&package_table[..], "com.android.aconfig.storage.test_3").unwrap();
        assert_eq!(package_offset, None);
        // this will land at the end of a linked list
        let package_offset =
            find_package_offset(&package_table[..], "com.android.aconfig.storage.test_5").unwrap();
        assert_eq!(package_offset, None);
    }

    #[test]
    // this test point locks down query error when file has a higher version
    fn test_higher_version_storage_file() {
        let mut table = create_test_package_table().unwrap();
        table.header.version = crate::FILE_VERSION + 1;
        let package_table = table.as_bytes();
        let error = find_package_offset(&package_table[..], "com.android.aconfig.storage.test_1")
            .unwrap_err();
        assert_eq!(
            format!("{:?}", error),
            format!(
                "Cannot read storage file with a higher version of {} with lib version {}",
                crate::FILE_VERSION + 1,
                crate::FILE_VERSION
            )
        );
    }
}