Anki: Replace once_cell with stabilized LazyCell / LazyLock as far as possible

Since 1.80: rust-lang/rust#109736 and rust-lang/rust#98165

Non-Thread-Safe Lazy → std::cell::LazyCell https://doc.rust-lang.org/nightly/std/cell/struct.LazyCell.html

Thread-safe SyncLazy → std::sync::LazyLock https://doc.rust-lang.org/nightly/std/sync/struct.LazyLock.html

The compiler accepted LazyCell only in minilints.

The final use in rslib/src/log.rs couldn't be replaced since get_or_try_init has not yet been standardized: rust-lang/rust#109737

Author: twwn

Cargo.lock

@@ -16,6 +16,5 @@ globset.workspace = true
 itertools.workspace = true
 maplit.workspace = true
 num_cpus.workspace = true
-once_cell.workspace = true
 walkdir.workspace = true
 which.workspace = true

build/ninja_gen/Cargo.toml

@@ -3,9 +3,9 @@
 
 use std::collections::HashMap;
 use std::fmt::Display;
+use std::sync::LazyLock;
 
 use camino::Utf8PathBuf;
-use once_cell::sync::Lazy;
 
 #[derive(Debug, Clone, Hash, Default)]
 pub enum BuildInput {
@@ -119,7 +119,7 @@ pub struct Glob {
     pub exclude: Option<String>,
 }
 
-static CACHED_FILES: Lazy<Vec<Utf8PathBuf>> = Lazy::new(|| cache_files());
+static CACHED_FILES: LazyLock<Vec<Utf8PathBuf>> = LazyLock::new(cache_files());
 
 /// Walking the source tree once instead of for each glob yields ~4x speed
 /// improvements.

build/ninja_gen/src/input.rs

@@ -16,7 +16,6 @@ camino.workspace = true
 clap.workspace = true
 fluent-syntax.workspace = true
 itertools.workspace = true
-once_cell.workspace = true
 regex.workspace = true
 serde_json.workspace = true
 snafu.workspace = true

ftl/Cargo.toml

@@ -6,6 +6,7 @@ use std::fs;
 use std::io::BufReader;
 use std::iter::FromIterator;
 use std::path::PathBuf;
+use std::sync::LazyLock;
 
 use anki_io::create_file;
 use anyhow::Context;
@@ -14,7 +15,6 @@ use clap::Args;
 use fluent_syntax::ast;
 use fluent_syntax::ast::Resource;
 use fluent_syntax::parser;
-use once_cell::sync::Lazy;
 use regex::Regex;
 use walkdir::DirEntry;
 use walkdir::WalkDir;
@@ -144,7 +144,8 @@ fn extract_nested_messages_and_terms(
     ftl_roots: &[impl AsRef<str>],
     used_ftls: &mut HashSet<String>,
 ) {
-    static REFERENCE: Lazy<Regex> = Lazy::new(|| Regex::new(r"\{\s*-?([-0-9a-z]+)\s*\}").unwrap());
+    static REFERENCE: LazyLock<Regex> =
+        LazyLock::new(|| Regex::new(r"\{\s*-?([-0-9a-z]+)\s*\}").unwrap());
     for_files_with_ending(ftl_roots, ".ftl", |entry| {
         let source = fs::read_to_string(entry.path()).expect("file not readable");
         for caps in REFERENCE.captures_iter(&source) {
@@ -196,12 +197,12 @@ fn entry_use_check(used_ftls: &HashSet<String>) -> impl Fn(&ast::Entry<&str>) ->
 }
 
 fn extract_references_from_file(refs: &mut HashSet<String>, entry: &DirEntry) {
-    static SNAKECASE_TR: Lazy<Regex> =
-        Lazy::new(|| Regex::new(r"\Wtr\s*\.([0-9a-z_]+)\W").unwrap());
-    static CAMELCASE_TR: Lazy<Regex> =
-        Lazy::new(|| Regex::new(r"\Wtr2?\.([0-9A-Za-z_]+)\W").unwrap());
-    static DESIGNER_STYLE_TR: Lazy<Regex> =
-        Lazy::new(|| Regex::new(r"<string>([0-9a-z_]+)</string>").unwrap());
+    static SNAKECASE_TR: LazyLock<Regex> =
+        LazyLock::new(|| Regex::new(r"\Wtr\s*\.([0-9a-z_]+)\W").unwrap());
+    static CAMELCASE_TR: LazyLock<Regex> =
+        LazyLock::new(|| Regex::new(r"\Wtr2?\.([0-9A-Za-z_]+)\W").unwrap());
+    static DESIGNER_STYLE_TR: LazyLock<Regex> =
+        LazyLock::new(|| Regex::new(r"<string>([0-9a-z_]+)</string>").unwrap());
 
     let file_name = entry.file_name().to_str().expect("non-unicode filename");
 

ftl/src/garbage_collection.rs

@@ -12,7 +12,6 @@ anki.workspace = true
 futures.workspace = true
 itertools.workspace = true
 linkcheck.workspace = true
-once_cell.workspace = true
 regex.workspace = true
 reqwest.workspace = true
 strum.workspace = true

rslib/linkchecker/Cargo.toml

@@ -6,14 +6,14 @@
 use std::borrow::Cow;
 use std::env;
 use std::iter;
+use std::sync::LazyLock;
 use std::time::Duration;
 
 use anki::links::help_page_link_suffix;
 use anki::links::help_page_to_link;
 use anki::links::HelpPage;
 use futures::StreamExt;
 use itertools::Itertools;
-use once_cell::sync::Lazy;
 use linkcheck::validation::check_web;
 use linkcheck::validation::Context;
 use linkcheck::validation::Reason;
@@ -70,9 +70,7 @@ impl From<&'static str> for CheckableUrl {
 }
 
 fn ts_help_pages() -> impl Iterator<Item = &'static str> {
-    static QUOTED_URL: Lazy<Regex> = Lazy::new(|| {
-        Regex::new("\"(http.+)\"").unwrap()
-    });
+    static QUOTED_URL: LazyLock<Regex> = LazyLock::new(|| Regex::new("\"(http.+)\"").unwrap());
 
     QUOTED_URL
         .captures_iter(include_str!("../../../ts/lib/tslib/help-page.ts"))

rslib/linkchecker/tests/links.rs

@@ -15,7 +15,6 @@ anyhow.workspace = true
 camino.workspace = true
 inflections.workspace = true
 itertools.workspace = true
-once_cell.workspace = true
 prost-reflect.workspace = true
 prost-types.workspace = true
 regex.workspace = true

rslib/proto_gen/Cargo.toml

@@ -7,6 +7,7 @@
 use std::collections::HashMap;
 use std::env;
 use std::path::PathBuf;
+use std::sync::LazyLock;
 
 use anki_io::read_to_string;
 use anki_io::write_file_if_changed;
@@ -16,7 +17,6 @@ use camino::Utf8Path;
 use inflections::Inflect;
 use itertools::Either;
 use itertools::Itertools;
-use once_cell::sync::Lazy;
 use prost_reflect::DescriptorPool;
 use prost_reflect::MessageDescriptor;
 use prost_reflect::MethodDescriptor;
@@ -238,8 +238,8 @@ pub fn add_must_use_annotations_to_file<E>(path: &Utf8Path, is_empty: E) -> Resu
 where
     E: Fn(&Utf8Path, &str) -> bool,
 {
-    static MESSAGE_OR_ENUM_RE: Lazy<Regex> =
-        Lazy::new(|| Regex::new(r"pub (struct|enum) ([[:alnum:]]+?)\s").unwrap());
+    static MESSAGE_OR_ENUM_RE: LazyLock<Regex> =
+        LazyLock::new(|| Regex::new(r"pub (struct|enum) ([[:alnum:]]+?)\s").unwrap());
     let contents = read_to_string(path)?;
     let contents = MESSAGE_OR_ENUM_RE.replace_all(&contents, |caps: &Captures| {
         let is_enum = caps.get(1).unwrap().as_str() == "enum";

rslib/proto_gen/src/lib.rs

@@ -5,6 +5,7 @@ use std::collections::HashMap;
 use std::mem::size_of;
 use std::sync::atomic::AtomicI32;
 use std::sync::atomic::Ordering;
+use std::sync::LazyLock;
 use std::sync::Mutex;
 
 use anki_proto::ankidroid::sql_value::Data;
@@ -16,7 +17,6 @@ use itertools::FoldWhile;
 use itertools::FoldWhile::Continue;
 use itertools::FoldWhile::Done;
 use itertools::Itertools;
-use once_cell::sync::Lazy;
 use rusqlite::ToSql;
 use serde::Deserialize;
 
@@ -110,8 +110,8 @@ fn select_slice_of_size<'a>(
 
 type SequenceNumber = i32;
 
-static HASHMAP: Lazy<Mutex<HashMap<CollectionId, HashMap<SequenceNumber, DbResponse>>>> =
-    Lazy::new(|| Mutex::new(HashMap::new()));
+static HASHMAP: LazyLock<Mutex<HashMap<CollectionId, HashMap<SequenceNumber, DbResponse>>>> =
+    LazyLock::new(|| Mutex::new(HashMap::new()));
 
 pub(crate) fn flush_single_result(col: &Collection, sequence_number: i32) {
     HASHMAP
@@ -244,7 +244,7 @@ pub(crate) fn next_sequence_number() -> i32 {
 
 // same as we get from
 // io.requery.android.database.CursorWindow.sCursorWindowSize
-static DB_COMMAND_PAGE_SIZE: Lazy<Mutex<usize>> = Lazy::new(|| Mutex::new(1024 * 1024 * 2));
+static DB_COMMAND_PAGE_SIZE: LazyLock<Mutex<usize>> = LazyLock::new(|| Mutex::new(1024 * 1024 * 2));
 
 pub(crate) fn set_max_page_size(size: usize) {
     let mut state = DB_COMMAND_PAGE_SIZE.lock().expect("Could not lock mutex");

rslib/src/ankidroid/db.rs

@@ -1,7 +1,8 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
-use once_cell::sync::Lazy;
+use std::sync::LazyLock;
+
 use regex::Regex;
 use reqwest::Client;
 use serde;
@@ -31,7 +32,7 @@ pub async fn ankihub_login<S: Into<String>>(
     client: Client,
 ) -> Result<LoginResponse> {
     let client = HttpAnkiHubClient::new("", client);
-    static EMAIL_RE: Lazy<Regex> = Lazy::new(|| {
+    static EMAIL_RE: LazyLock<Regex> = LazyLock::new(|| {
         Regex::new(r"^[a-zA-Z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$").unwrap()
     });
     let mut request = LoginRequest {

rslib/src/ankihub/login.rs

@@ -19,10 +19,10 @@ use std::ops::Deref;
 use std::result;
 use std::sync::Arc;
 use std::sync::Mutex;
+use std::sync::OnceLock;
 use std::thread::JoinHandle;
 
 use futures::future::AbortHandle;
-use once_cell::sync::OnceCell;
 use prost::Message;
 use reqwest::Client;
 use tokio::runtime;
@@ -53,7 +53,7 @@ pub struct BackendInner {
     server: bool,
     sync_abort: Mutex<Option<AbortHandle>>,
     progress_state: Arc<Mutex<ProgressState>>,
-    runtime: OnceCell<Runtime>,
+    runtime: OnceLock<Runtime>,
     state: Mutex<BackendState>,
     backup_task: Mutex<Option<JoinHandle<Result<()>>>>,
     media_sync_task: Mutex<Option<JoinHandle<Result<()>>>>,
@@ -88,7 +88,7 @@ impl Backend {
                 want_abort: false,
                 last_progress: None,
             })),
-            runtime: OnceCell::new(),
+            runtime: OnceLock::new(),
             state: Mutex::new(BackendState::default()),
             backup_task: Mutex::new(None),
             media_sync_task: Mutex::new(None),

rslib/src/backend/mod.rs

@@ -5,6 +5,7 @@ use std::borrow::Cow;
 use std::collections::HashMap;
 use std::collections::HashSet;
 use std::fmt::Write;
+use std::sync::LazyLock;
 
 use anki_proto::image_occlusion::get_image_occlusion_note_response::ImageOcclusion;
 use anki_proto::image_occlusion::get_image_occlusion_note_response::ImageOcclusionShape;
@@ -14,7 +15,6 @@ use nom::bytes::complete::tag;
 use nom::bytes::complete::take_while;
 use nom::combinator::map;
 use nom::IResult;
-use once_cell::sync::Lazy;
 use regex::Captures;
 use regex::Regex;
 
@@ -24,7 +24,7 @@ use crate::latex::contains_latex;
 use crate::template::RenderContext;
 use crate::text::strip_html_preserving_entities;
 
-static MATHJAX: Lazy<Regex> = Lazy::new(|| {
+static MATHJAX: LazyLock<Regex> = LazyLock::new(|| {
     Regex::new(
         r"(?xsi)
             (\\[(\[])       # 1 = mathjax opening tag

rslib/src/cloze.rs

@@ -6,10 +6,10 @@ use std::collections::HashMap;
 use std::fs::File;
 use std::io::Write;
 use std::sync::Arc;
+use std::sync::LazyLock;
 
 use anki_proto::import_export::ExportNoteCsvRequest;
 use itertools::Itertools;
-use once_cell::sync::Lazy;
 use regex::Regex;
 
 use super::metadata::Delimiter;
@@ -156,7 +156,7 @@ fn field_to_record_field(field: &str, with_html: bool) -> Cow<str> {
 }
 
 fn strip_redundant_sections(text: &str) -> Cow<str> {
-    static RE: Lazy<Regex> = Lazy::new(|| {
+    static RE: LazyLock<Regex> = LazyLock::new(|| {
         Regex::new(
             r"(?isx)
             <style>.*?</style>          # style elements
@@ -170,7 +170,8 @@ fn strip_redundant_sections(text: &str) -> Cow<str> {
 }
 
 fn strip_answer_side_question(text: &str) -> Cow<str> {
-    static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"(?is)^.*<hr id=answer>\n*").unwrap());
+    static RE: LazyLock<Regex> =
+        LazyLock::new(|| Regex::new(r"(?is)^.*<hr id=answer>\n*").unwrap());
     RE.replace_all(text.as_ref(), "")
 }
 

rslib/src/import_export/text/csv/export.rs

@@ -2,16 +2,16 @@
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
 use std::borrow::Cow;
+use std::sync::LazyLock;
 
-use once_cell::sync::Lazy;
 use regex::Captures;
 use regex::Regex;
 
 use crate::cloze::expand_clozes_to_reveal_latex;
 use crate::media::files::sha1_of_data;
 use crate::text::strip_html;
 
-pub(crate) static LATEX: Lazy<Regex> = Lazy::new(|| {
+pub(crate) static LATEX: LazyLock<Regex> = LazyLock::new(|| {
     Regex::new(
         r"(?xsi)
             \[latex\](.+?)\[/latex\]     # 1 - standard latex
@@ -23,7 +23,7 @@ pub(crate) static LATEX: Lazy<Regex> = Lazy::new(|| {
     )
     .unwrap()
 });
-static LATEX_NEWLINES: Lazy<Regex> = Lazy::new(|| {
+static LATEX_NEWLINES: LazyLock<Regex> = LazyLock::new(|| {
     Regex::new(
         r#"(?xi)
             <br( /)?>

rslib/src/latex.rs

@@ -52,7 +52,7 @@ pub mod undo;
 pub mod version;
 
 use std::env;
+use std::sync::LazyLock;
 
-use once_cell::sync::Lazy;
-
-pub(crate) static PYTHON_UNIT_TESTS: Lazy<bool> = Lazy::new(|| env::var("ANKI_TEST_MODE").is_ok());
+pub(crate) static PYTHON_UNIT_TESTS: LazyLock<bool> =
+    LazyLock::new(|| env::var("ANKI_TEST_MODE").is_ok());

rslib/src/lib.rs

@@ -6,11 +6,11 @@ use std::collections::HashMap;
 use std::collections::HashSet;
 use std::fs;
 use std::io;
+use std::sync::LazyLock;
 
 use anki_i18n::without_unicode_isolation;
 use anki_io::write_file;
 use data_encoding::BASE64;
-use once_cell::sync::Lazy;
 use regex::Regex;
 use tracing::debug;
 use tracing::info;
@@ -459,7 +459,7 @@ impl MediaChecker<'_> {
     }
 
     fn maybe_extract_inline_image<'a>(&mut self, fname_decoded: &'a str) -> Result<Cow<'a, str>> {
-        static BASE64_IMG: Lazy<Regex> = Lazy::new(|| {
+        static BASE64_IMG: LazyLock<Regex> = LazyLock::new(|| {
             Regex::new("(?i)^data:image/(jpg|jpeg|png|gif|webp|avif);base64,(.+)$").unwrap()
         });