update #31: Remove lazy_static dependency (#135)

Author: mrtryhard

Cargo.lock

@@ -27,7 +27,6 @@ rust-embed = { workspace = true }
 unic-langid = { workspace = true }
 env_logger = { workspace = true }
 log = { workspace = true }
-lazy_static = { workspace = true }
 
 [dev-dependencies]
 doc-comment = { workspace = true }
@@ -57,7 +56,6 @@ i18n-embed-fl = { version = "0.9.1", path = "./i18n-embed-fl" }
 thiserror = "1.0"
 log = "0.4"
 unic-langid = "0.9"
-lazy_static = "1.4.0"
 anyhow = "1.0"
 gettext = "0.4"
 tr = "0.1"

Cargo.toml

@@ -29,10 +29,9 @@ i18n-config = { workspace = true }
 gettext = { workspace = true, optional = true }
 log = { workspace = true }
 rust-embed = { workspace = true }
-lazy_static = { workspace = true, optional = true }
 
 [features]
 default = []
 
 # A feature to localize this library
-localize = ["i18n-embed", "gettext", "lazy_static"]
+localize = ["i18n-embed", "gettext"]

i18n-build/Cargo.toml

@@ -63,30 +63,31 @@ pub fn run(crt: Crate) -> Result<()> {
 
 #[cfg(feature = "localize")]
 mod localize_feature {
-    use lazy_static::lazy_static;
-
     use i18n_embed::{
         gettext::{gettext_language_loader, GettextLanguageLoader},
         DefaultLocalizer,
     };
+    use std::sync::OnceLock;
 
     use rust_embed::RustEmbed;
 
     #[derive(RustEmbed)]
     #[folder = "i18n/mo"]
     pub struct Translations;
 
-    lazy_static! {
-        static ref LANGUAGE_LOADER: GettextLanguageLoader = gettext_language_loader!();
-    }
-
     static TRANSLATIONS: Translations = Translations {};
 
+    fn language_loader() -> &'static GettextLanguageLoader {
+        static LANGUAGE_LOADER: OnceLock<GettextLanguageLoader> = OnceLock::new();
+
+        LANGUAGE_LOADER.get_or_init(|| gettext_language_loader!())
+    }
+
     /// Obtain a [Localizer](i18n_embed::Localizer) for localizing this library.
     ///
     /// ⚠️ *This API requires the following crate features to be activated: `localize`.*
     pub fn localizer() -> DefaultLocalizer<'static> {
-        DefaultLocalizer::new(&*LANGUAGE_LOADER, &TRANSLATIONS)
+        DefaultLocalizer::new(&*language_loader(), &TRANSLATIONS)
     }
 }
 

i18n-build/src/lib.rs

@@ -17,7 +17,6 @@ fluent = { workspace = true }
 fluent-syntax = { workspace = true }
 i18n-config = { workspace = true }
 i18n-embed = { workspace = true, features = ["fluent-system", "filesystem-assets"]}
-lazy_static = { workspace = true }
 proc-macro2 = { workspace = true }
 proc-macro-error2 = "2.0.1"
 quote = { workspace = true }

i18n-embed-fl/Cargo.toml

@@ -7,6 +7,7 @@ use quote::quote;
 use std::{
     collections::{HashMap, HashSet},
     path::Path,
+    sync::OnceLock,
 };
 use syn::{parse::Parse, parse_macro_input, spanned::Spanned};
 use unic_langid::LanguageIdentifier;
@@ -164,11 +165,10 @@ struct DomainSpecificData {
     _assets: FileSystemAssets,
 }
 
-lazy_static::lazy_static! {
-    /// Cached data specific to each localization domain, to improve
-    /// performance of subsequent macro invocations.
-    static ref DOMAINS: dashmap::DashMap<String, DomainSpecificData> =
-        dashmap::DashMap::new();
+fn domains() -> &'static dashmap::DashMap<String, DomainSpecificData> {
+    static DOMAINS: OnceLock<dashmap::DashMap<String, DomainSpecificData>> = OnceLock::new();
+
+    DOMAINS.get_or_init(|| dashmap::DashMap::new())
 }
 
 /// A macro to obtain localized messages and optionally their attributes, and check the `message_id`, `attribute_id`
@@ -347,7 +347,7 @@ pub fn fl(input: TokenStream) -> TokenStream {
         )
     };
 
-    let domain_data = if let Some(domain_data) = DOMAINS.get(&domain) {
+    let domain_data = if let Some(domain_data) = domains().get(&domain) {
         domain_data
     } else {
         let crate_paths = i18n_config::locate_crate_paths()
@@ -421,7 +421,7 @@ pub fn fl(input: TokenStream) -> TokenStream {
             _assets: assets,
         };
 
-        DOMAINS.entry(domain.clone()).or_insert(data).downgrade()
+        domains().entry(domain.clone()).or_insert(data).downgrade()
     };
 
     let message_id_string = match &message_id {

i18n-embed-fl/src/lib.rs

@@ -25,7 +25,6 @@ fluent-syntax = { workspace = true, optional = true }
 gettext = { workspace = true, optional = true }
 i18n-embed-impl = { workspace = true, optional = true }
 intl-memoizer = "0.5"
-lazy_static = { workspace = true }
 locale_config = { version = "0.3", optional = true }
 log = { workspace = true }
 notify = { version = "6.1.1", optional = true }

i18n-embed/Cargo.toml

@@ -248,32 +248,34 @@
 //! ```
 //! # #[cfg(all(feature = "fluent-system", feature = "desktop-requester"))]
 //! # {
-//! use std::sync::Arc;
+//! use std::sync::{Arc, OnceLock};
 //! use i18n_embed::{
 //!     DesktopLanguageRequester, LanguageRequester,
 //!     DefaultLocalizer, Localizer, fluent::FluentLanguageLoader     
 //! };
-//! use rust_embed::RustEmbed; use lazy_static::lazy_static;
+//! use rust_embed::RustEmbed;
 //! use unic_langid::LanguageIdentifier;
 //!
 //! #[derive(RustEmbed)]
 //! #[folder = "i18n/ftl"] // path to localization resources
 //! struct Localizations;
 //!
-//! lazy_static! {
-//!     static ref LANGUAGE_LOADER: FluentLanguageLoader = {
+//! pub fn language_loader() -> &'static FluentLanguageLoader {
+//!     static LANGUAGE_LOADER: OnceLock<FluentLanguageLoader> = OnceLock::new();
+//!
+//!     LANGUAGE_LOADER.get_or_init(|| {
 //!         // Usually you could use the fluent_language_loader!() macro
 //!         // to pull values from i18n.toml configuration and current
 //!         // module here at compile time, but instantiating the loader
 //!         // manually here instead so the example compiles.
 //!         let fallback: LanguageIdentifier = "en-US".parse().unwrap();
 //!         FluentLanguageLoader::new("test", fallback)
-//!     };
+//!     })
 //! }
 //!
 //! # #[allow(dead_code)]
 //! fn main() {
-//!     let localizer = DefaultLocalizer::new(&*LANGUAGE_LOADER, &Localizations);
+//!     let localizer = DefaultLocalizer::new(&*language_loader(), &Localizations);
 //!
 //!     let localizer_arc: Arc<dyn Localizer> = Arc::new(localizer);
 //!
@@ -297,7 +299,7 @@
 //! [DefaultLocalizer](DefaultLocalizer), but you can also implement
 //! the [Localizer](Localizer) trait yourself for a custom solution.
 //! It also makes use of
-//! [lazy_static](https://crates.io/crates/lazy_static) to allow the
+//! [OnceLock](https://doc.rust-lang.org/beta/std/sync/struct.OnceLock.html) to allow the
 //! [LanguageLoader](LanguageLoader) implementation to be stored
 //! statically, because its constructor is not `const`.
 //!
@@ -309,21 +311,23 @@
 //! ```
 //! # #[cfg(feature = "fluent-system")]
 //! # {
-//! use std::sync::Arc;
+//! use std::sync::{Arc, OnceLock};
 //! use i18n_embed::{
 //!     DefaultLocalizer, Localizer, LanguageLoader,
 //!     fluent::{
 //!         fluent_language_loader, FluentLanguageLoader     
 //! }};
-//! use rust_embed::RustEmbed; use lazy_static::lazy_static;
+//! use rust_embed::RustEmbed;
 //!
 //! #[derive(RustEmbed)]
 //! #[folder = "i18n/mo"] // path to the compiled localization resources
 //! struct Localizations;
 //!
-//! lazy_static! {
-//!     static ref LANGUAGE_LOADER: FluentLanguageLoader = {
-//!         let loader = fluent_language_loader!();
+//! fn language_loader() -> &'static FluentLanguageLoader {
+//!     static LANGUAGE_LOADER: OnceLock<FluentLanguageLoader> = OnceLock::new();
+//!
+//!     LANGUAGE_LOADER.get_or_init(|| {
+//!        let loader = fluent_language_loader!();
 //!
 //!         // Load the fallback langauge by default so that users of the
 //!         // library don't need to if they don't care about localization.
@@ -332,13 +336,13 @@
 //!             .expect("Error while loading fallback language");
 //!
 //!         loader
-//!     };
+//!     })
 //! }
 //!
 //! // Get the `Localizer` to be used for localizing this library.
 //! # #[allow(unused)]
 //! pub fn localizer() -> Arc<dyn Localizer> {
-//!     Arc::new(DefaultLocalizer::new(&*LANGUAGE_LOADER, &Localizations))
+//!     Arc::new(DefaultLocalizer::new(&*language_loader(), &Localizations))
 //! }
 //! # }
 //! ```
@@ -355,27 +359,27 @@
 //! for the library:
 //!
 //! ```
-//! # #[cfg(feature = "gettext-system")]
+//! #[cfg(feature = "gettext-system")]
 //! # {
-//! use std::sync::Arc;
+//! use std::sync::{Arc, OnceLock};
 //! use i18n_embed::{
 //!     DefaultLocalizer, Localizer, gettext::{
 //!     gettext_language_loader, GettextLanguageLoader     
 //! }};
 //! use i18n_embed::I18nAssets;
-//! use lazy_static::lazy_static;
 //!
-//! lazy_static! {
-//!     static ref LANGUAGE_LOADER: GettextLanguageLoader =
-//!         gettext_language_loader!();
+//! fn language_loader() -> &'static GettextLanguageLoader {
+//!     static LANGUAGE_LOADER: OnceLock<GettextLanguageLoader> = OnceLock::new();
+//!
+//!     LANGUAGE_LOADER.get_or_init(|| gettext_language_loader!())
 //! }
 //!
 //! /// Get the `Localizer` to be used for localizing this library,
 //! /// using the provided embedded source of language files `embed`.
 //! # #[allow(unused)]
 //! pub fn localizer<'a>(embed: &'a (dyn I18nAssets + Send + Sync + 'static)) -> Arc<dyn Localizer + 'a> {
 //!     Arc::new(DefaultLocalizer::new(
-//!         &*LANGUAGE_LOADER,
+//!         &*language_loader(),
 //!         embed
 //!     ))
 //! }

i18n-embed/src/lib.rs

@@ -6,11 +6,10 @@ use i18n_embed::{
     gettext::{gettext_language_loader, GettextLanguageLoader},
     DefaultLocalizer, DesktopLanguageRequester, LanguageLoader, LanguageRequester, Localizer,
 };
-use lazy_static::lazy_static;
 use rust_embed::RustEmbed;
 use std::{
     path::{Path, PathBuf},
-    sync::Arc,
+    sync::{Arc, OnceLock},
 };
 use tr::tr;
 use unic_langid::LanguageIdentifier;
@@ -19,12 +18,14 @@ use unic_langid::LanguageIdentifier;
 #[folder = "i18n/mo"]
 struct Translations;
 
-lazy_static! {
-    static ref LANGUAGE_LOADER: GettextLanguageLoader = gettext_language_loader!();
-}
-
 static TRANSLATIONS: Translations = Translations {};
 
+fn language_loader() -> &'static GettextLanguageLoader {
+    static LANGUAGE_LOADER: OnceLock<GettextLanguageLoader> = OnceLock::new();
+
+    LANGUAGE_LOADER.get_or_init(|| gettext_language_loader!())
+}
+
 /// Produce the message to be displayed when running `cargo i18n -h`.
 fn short_about() -> String {
     // The help message displayed when running `cargo i18n -h`.
@@ -76,7 +77,7 @@ fn main() -> Result<()> {
     let mut language_requester = DesktopLanguageRequester::new();
 
     let cargo_i18n_localizer: DefaultLocalizer<'static> =
-        DefaultLocalizer::new(&*LANGUAGE_LOADER, &TRANSLATIONS);
+        DefaultLocalizer::new(&*language_loader(), &TRANSLATIONS);
 
     let cargo_i18n_localizer_rc: Arc<dyn Localizer> = Arc::new(cargo_i18n_localizer);
     let i18n_build_localizer_rc: Arc<dyn Localizer> = Arc::new(i18n_build::localizer());
@@ -86,7 +87,7 @@ fn main() -> Result<()> {
     language_requester.poll()?;
 
     let fallback_locale: &'static str =
-        String::leak(LANGUAGE_LOADER.fallback_language().to_string());
+        String::leak(language_loader().fallback_language().to_string());
     let available_languages = available_languages(&*cargo_i18n_localizer_rc)?;
     let available_languages_slice: Vec<&'static str> = available_languages
         .into_iter()