1 files changed, 85 insertions, 0 deletions
diff --git a/core/src/default_impl/simple_context.rs b/core/src/default_impl/simple_context.rs
new file mode 100644
index 0000000..53d941d
--- /dev/null
+++ b/core/src/default_impl/simple_context.rs
@@ -0,0 +1,85 @@
+//! This module provides a type alias and constructor function for an simple context impl.
+//!
+//! It used the `FsResourceLoader` and `CpuPool` with a `CompositeContext`.
+//!
+//! Note this module is only available if the `default_impl_cpupool` feature
+//! is enabled.
+//!
+//! # Example
+//!
+//! ```
+//! # extern crate mail_core as mail;
+//! # extern crate mail_headers as headers;
+//! # use headers::header_components::Domain;
+//! # // It's re-exported in the facade under `default_impl`.
+//! # use std::str::FromStr;
+//! use mail::default_impl::simple_context;
+//!
+//! # fn main() {
+//! //TODO[FEAT]: use parse once the `Domain` component implements `FromStr`.
+//! //let domain = "example.com".parse().unwrap();
+//! let domain = Domain::from_unchecked("example.com".to_owned());
+//! // This normally should be world unique for any usage with the same domain.
+//! // This is necessary to generate `Content-Id` and `Message-Id` correctly.
+//! let ascii_unique_part = "xm3r2u".parse().unwrap();
+//! let ctx = simple_context::new(domain, ascii_unique_part).unwrap();
+//! # }
+//! ```
+//!
+use std::io;
+
+use soft_ascii_string::SoftAsciiString;
+use futures_cpupool::{Builder, CpuPool};
+
+use internals::error::EncodingError;
+use headers::header_components::Domain;
+
+use ::context::CompositeContext;
+use ::default_impl::{FsResourceLoader, HashedIdGen};
+
+/// Error returned when creating a "simple_context" fails.
+#[derive(Debug, Fail)]
+pub enum ContextSetupError {
+    /// Reading the env variables failed.
+    ///
+    /// (Mainly getting the current working dir failed).
+    #[fail(display="{}", _0)]
+    ReadingEnv(io::Error),
+
+    /// Punny encoding a non us-ascii domain failed.
+    #[fail(display="{}", _0)]
+    PunyCodingDomain(EncodingError)
+}
+
+/// Type Alias for a the type returned by `simple_context::new`.
+pub type Context = CompositeContext<FsResourceLoader, CpuPool, HashedIdGen>;
+
+/// create a new CompositeContext<FsResourceLoader, CpuPool, HashedIdGen>
+///
+/// It uses the current working directory as root for the `FsResourceLoader`,
+/// and the default settings for the `CpuPool`, both the `domain` and
+/// `unique_part` are passed to the `HashedIdGen::new` constructor.
+///
+/// Note that the combination of `unique_part` and `domain` should be world
+/// unique. This is needed to generate `Content-Id` and `Message-Id` reliably
+/// correctly. This means if you run multiple instances of softer using a context
+/// or you create multiple contexts they should _not_ use the same `unique_part`
+/// under any circumstances (expect if they use different domains, but then you
+/// also should only use domain you actually own).
+pub fn new(domain: Domain, unique_part: SoftAsciiString) -> Result<Context, ContextSetupError> {
+    let resource_loader = FsResourceLoader
+        ::with_cwd_root()
+        .map_err(|err| ContextSetupError::ReadingEnv(err))?;
+
+    let cpu_pool = Builder::new().create();
+
+    let id_gen = HashedIdGen
+        ::new(domain, unique_part)
+        .map_err(|err| ContextSetupError::PunyCodingDomain(err))?;
+
+    Ok(CompositeContext::new(
+        resource_loader,
+        cpu_pool,
+        id_gen,
+    ))
+}
+\ No newline at end of file