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// Copyright 2020 Tetrate // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. //! `Envoy` `Shared Data API`. use crate::host::{self, ByteString}; pub use crate::abi::proxy_wasm::types::OptimisticLockVersion; /// An interface of the `Envoy` `Shared Data API`. /// /// Basic usage of [`SharedData`]: /// /// ``` /// # use envoy_sdk as envoy; /// # use envoy::host::Result; /// # fn action() -> Result<()> { /// use envoy::host::SharedData; /// /// let shared_data = SharedData::default(); /// /// let value = shared_data.get("shared_key")?; /// /// shared_data.set("shared_key", b"shared value", None)?; /// # Ok(()) /// # } /// ``` /// /// Injecting [`SharedData`] into a HTTP Filter as a dependency: /// /// ``` /// # use envoy_sdk as envoy; /// use envoy::host::SharedData; /// /// struct MyHttpFilter<'a> { /// shared_data: &'a dyn SharedData, /// } /// /// impl<'a> MyHttpFilter<'a> { /// /// Creates a new instance parameterized with a given [`SharedData`] implementation. /// pub fn new(shared_data: &'a dyn SharedData) -> Self { /// MyHttpFilter { shared_data } /// } /// /// /// Creates a new instance parameterized with the default [`SharedData`] implementation. /// pub fn default() -> Self { /// Self::new(SharedData::default()) /// } /// } /// ``` /// /// [`SharedData`]: trait.SharedData.html pub trait SharedData { /// Returns shared data by key. /// /// # Arguments /// /// * `key` - key. /// /// # Return value /// /// * `value` - an opaque blob of bytes. /// * `version` - optimistic lock version. fn get(&self, key: &str) -> host::Result<(Option<ByteString>, Option<OptimisticLockVersion>)>; /// Shares data under a given key. /// /// # Arguments /// /// * `key` - key. /// * `value` - an opaque blob of bytes. /// * `version` - optimistic lock version. fn set( &self, key: &str, value: &[u8], version: Option<OptimisticLockVersion>, ) -> host::Result<()>; } impl dyn SharedData { /// Returns the default implementation that interacts with `Envoy` /// through its [`ABI`]. /// /// [`ABI`]: https://github.com/proxy-wasm/spec pub fn default() -> &'static dyn SharedData { &impls::Host } } mod impls { use super::SharedData; use crate::abi::proxy_wasm::hostcalls; use crate::abi::proxy_wasm::types::OptimisticLockVersion; use crate::host::{self, ByteString}; pub(super) struct Host; impl SharedData for Host { fn get( &self, key: &str, ) -> host::Result<(Option<ByteString>, Option<OptimisticLockVersion>)> { hostcalls::get_shared_data(key) } fn set( &self, key: &str, value: &[u8], version: Option<OptimisticLockVersion>, ) -> host::Result<()> { hostcalls::set_shared_data(key, value, version) } } }