Add a crate feature sync for enabling and disabling sync caches

.circleci/config.yml

@@ -12,7 +12,7 @@ jobs:
               --env RUSTFLAGS='--cfg circleci' \
               xd009642/tarpaulin \
               cargo tarpaulin -v \
-                --features 'future, dash' \
+                --features 'sync, future, dash' \
                 --ciserver circle-ci \
                 --coveralls ${COVERALLS_TOKEN} \
                 --timeout 600 \

.github/workflows/CI.yml

@@ -59,25 +59,32 @@ jobs:
           cargo update -p dashmap --precise 5.2.0
           cargo update -p hashbrown --precise 0.11.2
 
-      - name: Build (no features)
+      - name: Run tests (debug, sync feature)
         uses: actions-rs/cargo@v1
         with:
-          command: build
+          command: test
+          args: --features sync
+
+      - name: Run tests (release, sync feature)
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --release --features sync
 
-      - name: Run tests (release, no features)
+      - name: Run tests (future feature, but no sync feature)
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --release
+          args: --no-default-features --features 'future, atomic64, quanta'
 
-      - name: Run tests (future feature)
+      - name: Run tests (future and sync features)
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --features future
+          args: --features 'future, sync'
 
-      - name: Run tests (dash feature)
+      - name: Run tests (dash feature, but no sync feature)
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --features dash
+          args: --no-default-features --features 'dash, atomic64, quanta'

.github/workflows/CIQuantaDisabled.yml

@@ -59,25 +59,31 @@ jobs:
           cargo update -p dashmap --precise 5.2.0
           cargo update -p hashbrown --precise 0.11.2
 
-      - name: Build (no quanta feature)
+      - name: Run tests (debug, but no quanta feature)
         uses: actions-rs/cargo@v1
         with:
-          command: build
-          args: --no-default-features --features atomic64
+          command: test
+          args: --no-default-features --features 'sync, atomic64'
 
-      - name: Run tests (release, no quanta feature)
+      - name: Run tests (release, but no quanta feature)
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --release --no-default-features --features atomic64
+          args: --release --no-default-features --features 'sync, atomic64'
 
-      - name: Run tests (future feature, but no quanta feature)
+      - name: Run tests (future feature, but no quanta and sync features)
         uses: actions-rs/cargo@v1
         with:
           command: test
           args: --no-default-features --features 'future, atomic64'
 
-      - name: Run tests (dash feature, but no quanta feature)
+      - name: Run tests (future feature, but no quanta feature)
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --no-default-features --features 'sync, future, atomic64'
+
+      - name: Run tests (dash feature, but no quanta and sync features)
         uses: actions-rs/cargo@v1
         with:
           command: test

.github/workflows/LinuxCrossCompileTest.yml

@@ -59,12 +59,12 @@ jobs:
         with:
           command: clean
 
-      - name: Run tests (no features)
+      - name: Run tests (sync feature)
         uses: actions-rs/cargo@v1
         with:
           use-cross: true
           command: test
-          args: --release --target ${{ matrix.platform.target }} ${{ matrix.platform.cargo-opts }}
+          args: --release --features sync --target ${{ matrix.platform.target }} ${{ matrix.platform.cargo-opts }}
 
       - name: Run tests (future feature)
         uses: actions-rs/cargo@v1

.github/workflows/Skeptic.yml

@@ -50,23 +50,23 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --release --features 'future, dash'
+          args: --release --features 'sync, future, dash'
         env:
           RUSTFLAGS: '--cfg skeptic'
 
-      - name: Run tests (future and dash, without atomic64)
+      - name: Run tests (sync, future and dash, without atomic64 and quanta)
         uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --release --no-default-features --features 'future, dash'
+          args: --release --no-default-features --features 'sync, future, dash'
         env:
           RUSTFLAGS: '--cfg skeptic'
 
-      - name: Run compile error tests (future and dash features, trybuild)
+      - name: Run compile error tests (sync, future and dash features, trybuild)
         uses: actions-rs/cargo@v1
         if: ${{ matrix.rust == 'stable' }}
         with:
           command: test
-          args: ui_trybuild --release --features 'future, dash'
+          args: ui_trybuild --release --features 'sync, future, dash'
         env:
           RUSTFLAGS: '--cfg trybuild'

Cargo.toml

@@ -16,10 +16,14 @@ exclude = [".circleci", ".devcontainer", ".github", ".gitpod.yml", ".vscode"]
 build = "build.rs"
 
 [features]
-default = ["atomic64", "quanta"]
+default = ["sync", "atomic64", "quanta"]
+
+# This feature is enabled by default. Disable it when you do not need
+# `moka::sync::{Cache, SegmentedCache}`
+sync = ["crossbeam-epoch", "thiserror", "uuid"]
 
 # Enable this feature to use `moka::future::Cache`.
-future = ["async-io", "async-lock", "futures-util"]
+future = ["crossbeam-epoch", "thiserror", "uuid", "async-io", "async-lock", "futures-util"]
 
 # Enable this feature to use **experimental** `moka::dash::Cache`.
 # Please note that the APIs for this feature will be frequently changed in next
@@ -39,23 +43,23 @@ unstable-debug-counters = ["future"]
 
 [dependencies]
 crossbeam-channel = "0.5.4"
-crossbeam-epoch = "0.8.2"
 crossbeam-utils = "0.8"
 num_cpus = "1.13"
 once_cell = "1.7"
 parking_lot = "0.12"
-scheduled-thread-pool = "0.2.5"
+scheduled-thread-pool = "0.2.6"
 smallvec = "1.8"
 tagptr = "0.2"
-thiserror = "1.0"
-uuid = { version = "0.8", features = ["v4"] }
 
 # Opt-out serde and stable_deref_trait features
 # https://github.com/Manishearth/triomphe/pull/5
 triomphe = { version = "0.1", default-features = false }
 
-# Optional dependencies (quanta, enabled by default)
+# Optional dependencies (enabled by default)
+crossbeam-epoch = { version = "0.8.2", optional = true }
 quanta = { version = "0.10.0", optional = true }
+thiserror = { version = "1.0", optional = true }
+uuid = { version = "0.8", features = ["v4"], optional = true }
 
 # Optional dependencies (dashmap)
 dashmap = { version = "5.2", optional = true }

src/common.rs

@@ -1,9 +1,9 @@
 use std::convert::TryInto;
 
-// #[cfg(any(feature = "sync", feature = "future", feature = "dash"))]
+#[cfg(any(feature = "sync", feature = "future", feature = "dash"))]
 pub(crate) mod concurrent;
 
-// #[cfg(any(feature = "sync", feature = "future"))]
+#[cfg(any(feature = "sync", feature = "future"))]
 pub(crate) mod error;
 
 pub(crate) mod builder_utils;

src/common/concurrent.rs

@@ -77,7 +77,7 @@ impl<K> KeyDate<K> {
         &self.key
     }
 
-    // #[cfg(any(feature = "sync", feature = "future"))]
+    #[cfg(any(feature = "sync", feature = "future"))]
     pub(crate) fn last_modified(&self) -> Option<Instant> {
         self.entry_info.last_modified()
     }

src/common/concurrent/thread_pool.rs

@@ -5,19 +5,19 @@ use std::{collections::HashMap, sync::Arc};
 
 static REGISTRY: Lazy<ThreadPoolRegistry> = Lazy::new(ThreadPoolRegistry::default);
 
-#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
-// #[cfg_attr(any(feature = "sync", feature = "future"), derive(Debug))]
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
+#[cfg_attr(any(feature = "sync", feature = "future"), derive(Debug))]
 pub(crate) enum PoolName {
     Housekeeper,
-    // #[cfg(any(feature = "sync", feature = "future"))]
+    #[cfg(any(feature = "sync", feature = "future"))]
     Invalidator,
 }
 
 impl PoolName {
     fn thread_name_template(&self) -> &'static str {
         match self {
             PoolName::Housekeeper => "moka-housekeeper-{}",
-            // #[cfg(any(feature = "sync", feature = "future"))]
+            #[cfg(any(feature = "sync", feature = "future"))]
             PoolName::Invalidator => "moka-invalidator-{}",
         }
     }

src/common/deque.rs

@@ -116,7 +116,7 @@ impl<T> Deque<T> {
         self.region
     }
 
-    // #[cfg(any(test, feature = "sync", feature = "future"))]
+    #[cfg(any(test, feature = "sync", feature = "future"))]
     pub(crate) fn len(&self) -> usize {
         self.len
     }

src/common/time.rs

@@ -7,7 +7,7 @@ pub(crate) mod clock;
 pub(crate) use clock::Clock;
 
 #[cfg(test)]
-// #[cfg(all(test, feature = "sync"))]
+#[cfg(all(test, feature = "sync"))]
 pub(crate) use clock::Mock;
 
 /// a wrapper type over Instant to force checked additions and prevent

src/common/time/clock_quanta.rs

@@ -1,6 +1,5 @@
 pub(crate) type Clock = quanta::Clock;
 pub(crate) type Instant = quanta::Instant;
 
-#[cfg(test)]
-// #[cfg(all(test, feature = "sync"))]
+#[cfg(all(test, feature = "sync"))]
 pub(crate) type Mock = quanta::Mock;

src/future.rs

@@ -3,6 +3,8 @@
 //!
 //! To use this module, enable a crate feature called "future".
 
+use std::{hash::Hash, sync::Arc};
+
 mod builder;
 mod cache;
 mod value_initializer;
@@ -12,6 +14,34 @@ pub use {
     cache::{BlockingOp, Cache},
 };
 
+/// The type of the unique ID to identify a predicate used by
+/// [`Cache#invalidate_entries_if`][invalidate-if] method.
+///
+/// A `PredicateId` is a `String` of UUID (version 4).
+///
+/// [invalidate-if]: ./struct.Cache.html#method.invalidate_entries_if
+pub type PredicateId = String;
+
+pub struct Iter<'i, K, V>(crate::sync_base::iter::Iter<'i, K, V>);
+
+impl<'i, K, V> Iter<'i, K, V> {
+    pub(crate) fn new(inner: crate::sync_base::iter::Iter<'i, K, V>) -> Self {
+        Self(inner)
+    }
+}
+
+impl<'i, K, V> Iterator for Iter<'i, K, V>
+where
+    K: Eq + Hash + Send + Sync + 'static,
+    V: Clone + Send + Sync + 'static,
+{
+    type Item = (Arc<K>, V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
 /// Provides extra methods that will be useful for testing.
 pub trait ConcurrentCacheExt<K, V> {
     /// Performs any pending maintenance operations needed by the cache.

src/future/cache.rs

@@ -1,14 +1,13 @@
 use super::{
     value_initializer::{InitResult, ValueInitializer},
-    CacheBuilder, ConcurrentCacheExt,
+    CacheBuilder, ConcurrentCacheExt, Iter, PredicateId,
 };
 use crate::{
     common::concurrent::{
         constants::{MAX_SYNC_REPEATS, WRITE_RETRY_INTERVAL_MICROS},
         housekeeper::InnerSync,
         Weigher, WriteOp,
     },
-    sync::{Iter, PredicateId},
     sync_base::base_cache::{BaseCache, HouseKeeperArc},
     Policy, PredicateError,
 };
@@ -881,9 +880,10 @@ where
     /// ```
     ///
     pub fn iter(&self) -> Iter<'_, K, V> {
-        use crate::sync_base::iter::ScanningGet;
+        use crate::sync_base::iter::{Iter as InnerIter, ScanningGet};
 
-        Iter::with_single_cache_segment(&self.base, self.base.num_cht_segments())
+        let inner = InnerIter::with_single_cache_segment(&self.base, self.base.num_cht_segments());
+        Iter::new(inner)
     }
 
     /// Returns a `BlockingOp` for this cache. It provides blocking

src/lib.rs

@@ -162,7 +162,7 @@ pub(crate) mod common;
 pub(crate) mod policy;
 pub mod unsync;
 
-// #[cfg(any(feature = "sync", feature = "future"))]
+#[cfg(any(feature = "sync", feature = "future"))]
 pub(crate) mod cht;
 
 #[cfg(feature = "dash")]
@@ -173,13 +173,14 @@ pub mod dash;
 #[cfg_attr(docsrs, doc(cfg(feature = "future")))]
 pub mod future;
 
-// #[cfg(feature = "sync")]
+#[cfg(feature = "sync")]
+#[cfg_attr(docsrs, doc(cfg(feature = "sync")))]
 pub mod sync;
 
-// #[cfg(any(feature = "sync", feature = "future"))]
+#[cfg(any(feature = "sync", feature = "future"))]
 pub(crate) mod sync_base;
 
-// #[cfg(any(feature = "sync", feature = "future"))]
+#[cfg(any(feature = "sync", feature = "future"))]
 pub use common::error::PredicateError;
 
 pub use policy::Policy;

src/policy.rs

@@ -29,7 +29,7 @@ impl Policy {
         self.max_capacity
     }
 
-    // #[cfg(feature = "sync")]
+    #[cfg(feature = "sync")]
     pub(crate) fn set_max_capacity(&mut self, capacity: Option<u64>) {
         self.max_capacity = capacity;
     }
@@ -39,7 +39,7 @@ impl Policy {
         self.num_segments
     }
 
-    // #[cfg(feature = "sync")]
+    #[cfg(feature = "sync")]
     pub(crate) fn set_num_segments(&mut self, num: usize) {
         self.num_segments = num;
     }

src/sync_base/base_cache.rs

@@ -1,6 +1,7 @@
 use super::{
     invalidator::{GetOrRemoveEntry, InvalidationResult, Invalidator, KeyDateLite, PredicateFun},
     iter::ScanningGet,
+    PredicateId,
 };
 
 use crate::{
@@ -23,7 +24,6 @@ use crate::{
         time::{CheckedTimeOps, Clock, Instant},
         CacheRegion,
     },
-    sync::PredicateId,
     Policy, PredicateError,
 };
 

src/sync_base/iter.rs

@@ -40,7 +40,7 @@ impl<'i, K, V> Iter<'i, K, V> {
         }
     }
 
-    // #[cfg(feature = "sync")]
+    #[cfg(feature = "sync")]
     pub(crate) fn with_multiple_cache_segments(
         cache_segments: Box<[&'i dyn ScanningGet<K, V>]>,
         num_cht_segments: usize,