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| </pre><pre class="rust"><code><span class="kw">use </span>std::io::BufRead; |
| <span class="kw">use </span>std::path::Path; |
| <span class="kw">use </span>std::sync::atomic::{AtomicUsize, Ordering}; |
| <span class="kw">use </span>std::sync::Arc; |
| <span class="kw">use </span>std::time::Duration; |
| <span class="attribute">#[cfg(not(target_vendor = <span class="string">"teaclave"</span>))] |
| </span><span class="kw">use </span>std::fs; |
| <span class="attribute">#[cfg(target_vendor = <span class="string">"teaclave"</span>)] |
| </span><span class="kw">use </span>std::untrusted::fs; |
| <span class="kw">use </span>std::{io, thread}; |
| |
| <span class="kw">use </span>crc32fast::Hasher; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::directory::{WatchCallback, WatchCallbackList, WatchHandle}; |
| |
| <span class="kw">const </span>POLLING_INTERVAL: Duration = Duration::from_millis(<span class="kw">if </span><span class="macro">cfg!</span>(test) { <span class="number">1 </span>} <span class="kw">else </span>{ <span class="number">500 </span>}); |
| |
| <span class="comment">// Watches a file and executes registered callbacks when the file is modified. |
| </span><span class="kw">pub struct </span>FileWatcher { |
| path: Arc<Path>, |
| callbacks: Arc<WatchCallbackList>, |
| state: Arc<AtomicUsize>, <span class="comment">// 0: new, 1: runnable, 2: terminated |
| </span>} |
| |
| <span class="kw">impl </span>FileWatcher { |
| <span class="kw">pub fn </span>new(path: <span class="kw-2">&</span>Path) -> FileWatcher { |
| FileWatcher { |
| path: Arc::from(path), |
| callbacks: Default::default(), |
| state: Default::default(), |
| } |
| } |
| |
| <span class="kw">pub fn </span>spawn(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="kw">if </span><span class="self">self |
| </span>.state |
| .compare_exchange(<span class="number">0</span>, <span class="number">1</span>, Ordering::SeqCst, Ordering::SeqCst) |
| .is_err() |
| { |
| <span class="kw">return</span>; |
| } |
| |
| <span class="kw">let </span>path = <span class="self">self</span>.path.clone(); |
| <span class="kw">let </span>callbacks = <span class="self">self</span>.callbacks.clone(); |
| <span class="kw">let </span>state = <span class="self">self</span>.state.clone(); |
| |
| thread::Builder::new() |
| .name(<span class="string">"thread-tantivy-meta-file-watcher"</span>.to_string()) |
| .spawn(<span class="kw">move </span>|| { |
| <span class="kw">let </span><span class="kw-2">mut </span>current_checksum_opt = <span class="prelude-val">None</span>; |
| |
| <span class="kw">while </span>state.load(Ordering::SeqCst) == <span class="number">1 </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Ok</span>(checksum) = FileWatcher::compute_checksum(<span class="kw-2">&</span>path) { |
| <span class="kw">let </span>metafile_has_changed = current_checksum_opt |
| .map(|current_checksum| current_checksum != checksum) |
| .unwrap_or(<span class="bool-val">true</span>); |
| <span class="kw">if </span>metafile_has_changed { |
| <span class="macro">info!</span>(<span class="string">"Meta file {:?} was modified"</span>, path); |
| current_checksum_opt = <span class="prelude-val">Some</span>(checksum); |
| <span class="comment">// We actually ignore callbacks failing here. |
| // We just wait for the end of their execution. |
| </span><span class="kw">let _ </span>= callbacks.broadcast().wait(); |
| } |
| } |
| |
| thread::sleep(POLLING_INTERVAL); |
| } |
| }) |
| .expect(<span class="string">"Failed to spawn meta file watcher thread"</span>); |
| } |
| |
| <span class="kw">pub fn </span>watch(<span class="kw-2">&</span><span class="self">self</span>, callback: WatchCallback) -> WatchHandle { |
| <span class="kw">let </span>handle = <span class="self">self</span>.callbacks.subscribe(callback); |
| <span class="self">self</span>.spawn(); |
| handle |
| } |
| |
| <span class="kw">fn </span>compute_checksum(path: <span class="kw-2">&</span>Path) -> <span class="prelude-ty">Result</span><u32, io::Error> { |
| <span class="kw">let </span>reader = <span class="kw">match </span>fs::File::open(path) { |
| <span class="prelude-val">Ok</span>(f) => io::BufReader::new(f), |
| <span class="prelude-val">Err</span>(e) => { |
| <span class="macro">warn!</span>(<span class="string">"Failed to open meta file {:?}: {:?}"</span>, path, e); |
| <span class="kw">return </span><span class="prelude-val">Err</span>(e); |
| } |
| }; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>hasher = Hasher::new(); |
| |
| <span class="kw">for </span>line <span class="kw">in </span>reader.lines() { |
| hasher.update(line<span class="question-mark">?</span>.as_bytes()) |
| } |
| |
| <span class="prelude-val">Ok</span>(hasher.finalize()) |
| } |
| } |
| |
| <span class="kw">impl </span>Drop <span class="kw">for </span>FileWatcher { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="self">self</span>.state.store(<span class="number">2</span>, Ordering::SeqCst); |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| |
| <span class="kw">use </span>std::mem; |
| |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use </span><span class="kw">crate</span>::directory::mmap_directory::atomic_write; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_file_watcher_drop_watcher() -> <span class="kw">crate</span>::Result<()> { |
| <span class="kw">let </span>tmp_dir = tempfile::TempDir::new()<span class="question-mark">?</span>; |
| <span class="kw">let </span>tmp_file = tmp_dir.path().join(<span class="string">"watched.txt"</span>); |
| |
| <span class="kw">let </span>counter: Arc<AtomicUsize> = Default::default(); |
| <span class="kw">let </span>(tx, rx) = crossbeam_channel::unbounded(); |
| <span class="kw">let </span>timeout = Duration::from_millis(<span class="number">100</span>); |
| |
| <span class="kw">let </span>watcher = FileWatcher::new(<span class="kw-2">&</span>tmp_file); |
| |
| <span class="kw">let </span>state = watcher.state.clone(); |
| <span class="macro">assert_eq!</span>(state.load(Ordering::SeqCst), <span class="number">0</span>); |
| |
| <span class="kw">let </span>counter_clone = counter.clone(); |
| |
| <span class="kw">let </span>_handle = watcher.watch(WatchCallback::new(<span class="kw">move </span>|| { |
| <span class="kw">let </span>val = counter_clone.fetch_add(<span class="number">1</span>, Ordering::SeqCst); |
| tx.send(val + <span class="number">1</span>).unwrap(); |
| })); |
| |
| <span class="macro">assert_eq!</span>(counter.load(Ordering::SeqCst), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(state.load(Ordering::SeqCst), <span class="number">1</span>); |
| |
| atomic_write(<span class="kw-2">&</span>tmp_file, <span class="string">b"foo"</span>)<span class="question-mark">?</span>; |
| <span class="macro">assert_eq!</span>(rx.recv_timeout(timeout), <span class="prelude-val">Ok</span>(<span class="number">1</span>)); |
| |
| atomic_write(<span class="kw-2">&</span>tmp_file, <span class="string">b"foo"</span>)<span class="question-mark">?</span>; |
| <span class="macro">assert!</span>(rx.recv_timeout(timeout).is_err()); |
| |
| atomic_write(<span class="kw-2">&</span>tmp_file, <span class="string">b"bar"</span>)<span class="question-mark">?</span>; |
| <span class="macro">assert_eq!</span>(rx.recv_timeout(timeout), <span class="prelude-val">Ok</span>(<span class="number">2</span>)); |
| |
| mem::drop(watcher); |
| |
| atomic_write(<span class="kw-2">&</span>tmp_file, <span class="string">b"qux"</span>)<span class="question-mark">?</span>; |
| thread::sleep(Duration::from_millis(<span class="number">10</span>)); |
| <span class="macro">assert_eq!</span>(counter.load(Ordering::SeqCst), <span class="number">2</span>); |
| <span class="macro">assert_eq!</span>(state.load(Ordering::SeqCst), <span class="number">2</span>); |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_file_watcher_drop_handle() -> <span class="kw">crate</span>::Result<()> { |
| <span class="kw">let </span>tmp_dir = tempfile::TempDir::new()<span class="question-mark">?</span>; |
| <span class="kw">let </span>tmp_file = tmp_dir.path().join(<span class="string">"watched.txt"</span>); |
| |
| <span class="kw">let </span>counter: Arc<AtomicUsize> = Default::default(); |
| <span class="kw">let </span>(tx, rx) = crossbeam_channel::unbounded(); |
| <span class="kw">let </span>timeout = Duration::from_millis(<span class="number">100</span>); |
| |
| <span class="kw">let </span>watcher = FileWatcher::new(<span class="kw-2">&</span>tmp_file); |
| |
| <span class="kw">let </span>state = watcher.state.clone(); |
| <span class="macro">assert_eq!</span>(state.load(Ordering::SeqCst), <span class="number">0</span>); |
| |
| <span class="kw">let </span>counter_clone = counter.clone(); |
| |
| <span class="kw">let </span>handle = watcher.watch(WatchCallback::new(<span class="kw">move </span>|| { |
| <span class="kw">let </span>val = counter_clone.fetch_add(<span class="number">1</span>, Ordering::SeqCst); |
| tx.send(val + <span class="number">1</span>).unwrap(); |
| })); |
| |
| <span class="macro">assert_eq!</span>(counter.load(Ordering::SeqCst), <span class="number">0</span>); |
| <span class="macro">assert_eq!</span>(state.load(Ordering::SeqCst), <span class="number">1</span>); |
| |
| atomic_write(<span class="kw-2">&</span>tmp_file, <span class="string">b"foo"</span>)<span class="question-mark">?</span>; |
| <span class="macro">assert_eq!</span>(rx.recv_timeout(timeout), <span class="prelude-val">Ok</span>(<span class="number">1</span>)); |
| |
| mem::drop(handle); |
| |
| atomic_write(<span class="kw-2">&</span>tmp_file, <span class="string">b"qux"</span>)<span class="question-mark">?</span>; |
| <span class="macro">assert_eq!</span>(counter.load(Ordering::SeqCst), <span class="number">1</span>); |
| <span class="macro">assert_eq!</span>(state.load(Ordering::SeqCst), <span class="number">1</span>); |
| |
| <span class="prelude-val">Ok</span>(()) |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="tantivy" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
