129 lines
3.4 KiB
Rust
129 lines
3.4 KiB
Rust
// Copyright 2015-2018 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Fetchable Dapps support.
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use std::fs;
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use linked_hash_map::LinkedHashMap;
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use page::local;
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use handlers::FetchControl;
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pub enum ContentStatus {
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Fetching(FetchControl),
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Ready(local::Dapp),
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}
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#[derive(Default)]
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pub struct ContentCache {
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cache: LinkedHashMap<String, ContentStatus>,
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}
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impl ContentCache {
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pub fn insert(&mut self, content_id: String, status: ContentStatus) -> Option<ContentStatus> {
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self.cache.insert(content_id, status)
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}
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pub fn remove(&mut self, content_id: &str) -> Option<ContentStatus> {
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self.cache.remove(content_id)
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}
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pub fn get(&mut self, content_id: &str) -> Option<&mut ContentStatus> {
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self.cache.get_refresh(content_id)
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}
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pub fn clear_garbage(&mut self, expected_size: usize) -> Vec<(String, ContentStatus)> {
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let len = self.cache.len();
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if len <= expected_size {
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return Vec::new();
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}
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let mut removed = Vec::with_capacity(len - expected_size);
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while self.cache.len() > expected_size {
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let entry = self.cache.pop_front().expect("expected_size bounded at 0, len is greater; qed");
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match entry.1 {
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ContentStatus::Fetching(ref fetch) => {
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trace!(target: "dapps", "Aborting {} because of limit.", entry.0);
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// Mark as aborted
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fetch.abort()
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},
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ContentStatus::Ready(ref endpoint) => {
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trace!(target: "dapps", "Removing {} because of limit.", entry.0);
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// Remove path (dir or file)
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let res = fs::remove_dir_all(&endpoint.path()).or_else(|_| fs::remove_file(&endpoint.path()));
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if let Err(e) = res {
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warn!(target: "dapps", "Unable to remove dapp/content from cache: {:?}", e);
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}
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}
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}
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removed.push(entry);
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}
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removed
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}
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#[cfg(test)]
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pub fn len(&self) -> usize {
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self.cache.len()
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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fn only_keys(data: Vec<(String, ContentStatus)>) -> Vec<String> {
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data.into_iter().map(|x| x.0).collect()
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}
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#[test]
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fn should_remove_least_recently_used() {
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// given
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let mut cache = ContentCache::default();
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cache.insert("a".into(), ContentStatus::Fetching(Default::default()));
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cache.insert("b".into(), ContentStatus::Fetching(Default::default()));
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cache.insert("c".into(), ContentStatus::Fetching(Default::default()));
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// when
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let res = cache.clear_garbage(2);
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// then
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assert_eq!(cache.len(), 2);
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assert_eq!(only_keys(res), vec!["a"]);
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}
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#[test]
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fn should_update_lru_if_accessed() {
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// given
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let mut cache = ContentCache::default();
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cache.insert("a".into(), ContentStatus::Fetching(Default::default()));
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cache.insert("b".into(), ContentStatus::Fetching(Default::default()));
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cache.insert("c".into(), ContentStatus::Fetching(Default::default()));
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// when
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cache.get("a");
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let res = cache.clear_garbage(2);
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// then
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assert_eq!(cache.len(), 2);
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assert_eq!(only_keys(res), vec!["b"]);
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}
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}
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