rust-shed: add no-op cachelib_stub implementation to the shed

Reviewed By: StanislavGlebik

Differential Revision: D20337902

fbshipit-source-id: 51adc6fa19ba22600be2fe543f4c14435cf9a01c

Author: lukaspiatkowski

Cargo.toml

@@ -5,6 +5,7 @@ members = [
     "shed/async_compression",
     "shed/async_unit",
     "shed/bytes_ext",
+    "shed/cachelib_stub",
     "shed/chrome_trace",
     "shed/cloned",
     "shed/codegen_includer_proc_macro",

shed/cachelib_stub/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "cachelib"
+edition = "2018"
+version = "0.1.0"
+authors = ['Facebook']
+license = "GPLv2+"
+include = ["src/**/*.rs"]
+
+[dependencies]
+futures_ext = { path = "../futures_ext" }
+abomonation = "0.7"
+anyhow = "1.0"
+bytes = { version = "0.5", features = ["serde"] }

shed/cachelib_stub/src/abomonation_future_cache.rs

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This software may be used and distributed according to the terms of the
+ * GNU General Public License found in the LICENSE file in the root
+ * directory of this source tree.
+ */
+
+use anyhow::{Error, Result};
+use futures_ext::BoxFuture;
+
+use crate::lrucache::VolatileLruCachePool;
+
+pub fn get_cached_or_fill<T, F>(
+    _cache_pool: &VolatileLruCachePool,
+    _cache_key: String,
+    fetch: F,
+) -> BoxFuture<Option<T>, Error>
+where
+    T: abomonation::Abomonation + Clone + Send + 'static,
+    F: FnOnce() -> BoxFuture<Option<T>, Error>,
+{
+    fetch()
+}
+
+pub fn get_cached<T>(_cache_pool: &VolatileLruCachePool, _cache_key: &String) -> Result<Option<T>>
+where
+    T: abomonation::Abomonation + Clone + Send + 'static,
+{
+    Ok(None)
+}
+
+/// Returns `false` if the entry could not be inserted (e.g. another entry with the same
+/// key was inserted first)
+pub fn set_cached<T>(
+    _cache_pool: &VolatileLruCachePool,
+    _cache_key: &String,
+    _entry: &T,
+) -> Result<bool>
+where
+    T: abomonation::Abomonation + Clone + Send + 'static,
+{
+    Ok(false)
+}

shed/cachelib_stub/src/lib.rs

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This software may be used and distributed according to the terms of the
+ * GNU General Public License found in the LICENSE file in the root
+ * directory of this source tree.
+ */
+
+#![deny(warnings)]
+
+#[cfg(not(fbcode_build))]
+mod abomonation_future_cache;
+#[cfg(not(fbcode_build))]
+mod lrucache;
+
+#[cfg(not(fbcode_build))]
+pub use crate::abomonation_future_cache::*;
+#[cfg(not(fbcode_build))]
+pub use crate::lrucache::*;
+
+// export Abomonation so that users of this crate don't need to add abomination as dependency
+#[cfg(not(fbcode_build))]
+pub use abomonation::Abomonation;
+
+#[cfg(fbcode_build)]
+pub use cachelib::*;