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|
//! # Global Database representation
//!
//! [`Db::blockchain`] is just the last block that was mined.
//! All the blocks are written to disk as text files whenever they are accepted.
//!
//! [`Db::pending_transactions`] is the in memory representation of the waiting transactions.
//! Every user can have only one outstanding transaction at any given time.
//!
//! [`Db::users`] is the in memory representation of the users,
//! with their public keys, `metu_ids` and gradecoin balances.
use crate::block::{Block, Fingerprint, Id, Transaction};
use crate::config::{BotConfig, Config};
use crate::student::{MetuId, User, UserAtRest};
use log::info;
use parking_lot::RwLock;
use std::{collections::HashMap, fs, io, path::PathBuf, sync::Arc};
#[derive(Debug, Clone, Default)]
pub struct Db {
pub blockchain: Arc<RwLock<Block>>,
pub pending_transactions: Arc<RwLock<HashMap<Id, Transaction>>>,
pub users: Arc<RwLock<HashMap<Fingerprint, User>>>,
pub config: Config,
preapproved_users: Vec<MetuId>,
}
impl Db {
pub fn new(config: Config) -> Self {
fs::create_dir_all(format!("blocks/{}", config.name)).unwrap();
fs::create_dir_all(format!("users/{}", config.name)).unwrap();
// Load bots
let users: HashMap<Fingerprint, User> = get_bots(&config.bots);
// Load the list of users who can register
let preapproved_users = read_approved_users(&config.preapproved_users);
let mut db = Db {
blockchain: Arc::new(RwLock::new(Block::default())),
pending_transactions: Arc::new(RwLock::new(HashMap::new())),
users: Arc::new(RwLock::new(users)),
config,
preapproved_users,
};
// Load the latest block, continue from where we left off
if let Some(block_path) = last_block_content(&db.config.name) {
db.populate_with_last_block(block_path);
}
// Load the users that had registered themselves
if let Ok(users_path) = read_users(&db.config.name) {
db.populate_with_users(users_path);
}
db
}
fn populate_with_last_block(&mut self, path: String) {
info!("Populating db with the latest block {}", path);
let file = fs::read(path).unwrap();
let json = std::str::from_utf8(&file).unwrap();
let block: Block = serde_json::from_str(json).unwrap();
*self.blockchain.write() = block;
}
fn populate_with_users(&mut self, files: Vec<PathBuf>) {
for fs in files {
if let Ok(file_content) = fs::read(fs) {
let json =
String::from_utf8(file_content).expect("we have written a malformed user file");
let user_at_rest: UserAtRest = serde_json::from_str(&json).unwrap();
info!("Populating db with user: {:?}", user_at_rest);
self.users
.write()
.insert(user_at_rest.fingerprint, user_at_rest.user);
}
}
}
pub fn is_user_preapproved(&self, id: &Id, passwd: &String) -> bool {
for user in &self.preapproved_users {
if *user.get_id() == *id && *user.get_passwd() == *passwd {
return true;
}
}
false
}
}
fn last_block_content(config_name: &str) -> Option<String> {
let blocks = read_block_name(config_name).unwrap();
if blocks.is_empty() {
return None;
}
let last_block = blocks[0].to_str().unwrap();
let mut last_block = parse_block(last_block);
let mut last_block_index = 0;
for (index, block) in blocks.iter().enumerate() {
let block = block.to_str().unwrap();
let block = parse_block(block);
if block > last_block {
last_block = block;
last_block_index = index;
}
}
return Some(blocks[last_block_index].to_str().unwrap().parse().unwrap());
}
fn read_block_name(config_name: &str) -> io::Result<Vec<PathBuf>> {
let path = format!("./blocks/{}", config_name);
let entries = fs::read_dir(path)?
.map(|res| res.map(|e| e.path()))
.collect::<Result<Vec<_>, io::Error>>()?;
Ok(entries)
}
fn parse_block(path: &str) -> u64 {
let start_pos = path.rfind('/').unwrap() + 1;
let end_pos = path.find(".block").unwrap();
let block_str = path[start_pos..end_pos].to_string();
let block_u64: u64 = block_str.parse().unwrap();
block_u64
}
fn read_users(config_name: &str) -> io::Result<Vec<PathBuf>> {
let path = format!("./users/{}", config_name);
let entries = fs::read_dir(path)?
.map(|res| res.map(|e| e.path()))
.collect::<Result<Vec<_>, io::Error>>()?;
Ok(entries)
}
/// Build bots from the given set of bot configurations.
fn get_bots(bot_configs: &HashMap<Fingerprint, BotConfig>) -> HashMap<Fingerprint, User> {
let mut index = 0;
bot_configs
.iter()
.map(|(fingerprint, config)| {
index += 1;
(
fingerprint.to_string(),
User {
user_id: MetuId::new(format!("friend_{}", index), "not_used".to_owned()),
public_key: "not_used".to_owned(),
balance: config.starting_balance,
is_bot: true,
},
)
})
.collect()
}
fn read_approved_users(filename: &str) -> Vec<MetuId> {
let mut approved_students: Vec<MetuId> = Vec::new();
let contents = fs::read_to_string(filename).unwrap_or_else(|_| {
panic!(
"{}",
format!(
"Expected {} in place to load preapproved students",
filename
)
)
});
let mut reader = csv::Reader::from_reader(contents.as_bytes());
for student in reader.records() {
let student = student.unwrap();
approved_students.push(MetuId::new(student[0].to_owned(), student[1].to_owned()));
}
approved_students
}
|
