//!
//! This crate provides header specific functionality for the `mail`
//! crate. This includes:
//!
//! - `HeaderName`, `Header` and `HeaderMap` as for the general API
//! - `HeaderTryFrom`, `HeaderTryInto` as the `TryFrom`/`TryInto`
//!   traits are not stable but we need something similar to their
//!   functionality.
//! - a number of headers like `_To`,`_From`, `Sender`, `Subject`
//!   and many more (Note that `_To` and `_From` are prefixed with
//!   and `_` to prevent name collisions when importing them, i.e.
//!   importing `_From as From` would shadow `std::convert::From`
//!   which can lead to extremely irritating errors).
//! - a number of components which are used to represent the
//!   content/field body of an header field e.g. `MailboxList`
//!   or `Email`. They are placed in the `components` module.
//! - a `headers!` macro for making the creation of an `HeaderMap`
//!   with a number of headers easier.
//! - a `def_headers!` macro for defining new custom headers
//!
//! ## Example (HeaderMap)
//!
//! A header map is a collection representing a number
//! of mail headers in an specific order. It can be
//! created like this:
//!
//! ```
//! # #[macro_use]
//! # extern crate mail_headers;
//!
//! // just import all headers
//! use mail_headers::headers::*;
//! use mail_headers::HeaderMap;
//! use mail_headers::error::ComponentCreationError;
//!
//! fn create_headers() -> Result<HeaderMap, ComponentCreationError> {
//!     headers!{
//!         // from and to can have multiple values
//!         // until specialization is stable is array
//!         // is necessary
//!         _From: [("My Fancy Display Name", "theduck@example.com")],
//!         _To: [ "unknown@example.com", ],
//!         Subject: "Who are you?"
//!     }
//! }
//!
//! fn main() {
//!     let headers = create_headers().unwrap();
//!     assert_eq!(headers.len(), 3);
//! }
//! ```
//!
//! ## Example (custom header)
//!
//! If needed users of the `mail` crate can create their own
//! headers, through this should be done with care.
//!
//! Note that the second field (then `unchecked { <name> }`),
//! expects a specific naming scheme, the auto-generated test
//! do check if it's violated but if you just run the code and
//! ignore the failing tests strange error can occure. (
//! The scheme is a capitalise the first letter of each
//! word and write all other letter in lower case, i.e.
//! `X-Id` is ok but `X-ID` isn't). The reason for this is because
//! of the way the header does the field lookup. While this
//! is not nice, for most use cases there is no need to
//! generate custom headers and in the future this might be
//! circumvented by auto-generating the name with a proc-derive.
//!
//! ```
//! # #[macro_use]
//! # extern crate mail_headers;
//!
//! use mail_headers::header_components;
//!
//! // this will define two headers `XFooEmail` and `XBarMailbox`
//! // the first will add a header field named `X-Foo-Email` with
//! // a value which is an `components::Email` and the second will
//! // add field with a value which is an `components::Mailbox`.
//! //
//! // Note that through the way they are defined `XFooEmail` can
//! // at most appear 1 time in an header map, while `XBarMailbox`
//! // can appear multiple times. Be aware that this is checked through
//! // so called validators which needs to be explicitly run, which they
//! // are if this header map is used to create a mail (running them
//! // when adding fields would be a mess as you would have to add
//! // transactions which can add/remove multiple fields at once, and
//! // implementing auto-generation for some fields which are required if
//! // some other fields are given in a certain way would be harder too).
//!
//! // If in scope both can be used in the `headers!` macro,
//! // like any other header.
//! //
//! def_headers! {
//!     // the name of the auto-generated test
//!     test_name: validate_header_names,
//!
//!     // the scope from which all components should be imported
//!     // E.g. `DateTime` refers to `components::DateTime`.
//!     scope: header_components,
//!
//!     // definitions of the headers or the form
//!     // <type_name>, unchecked { <filed_name> }, <component>, <maxOne>, <validator>
//!     XFooEmail, unchecked { "X-Foo-Email"      }, Email ,   maxOne, None,
//!     XBarMailbox, unchecked { "X-Bar-Mailbox" }, Mailbox,   multi,  None
//! }
//!
//! fn main() {
//!     let headers = headers! {
//!         XFooEmail: "123@example.com",
//!         XBarMailbox: ("My Funy Name", "notfunny@example.com"),
//!         XBarMailbox: "without.display.name@example.com"
//!     }.unwrap();
//! }
//! ```

extern crate media_type;
#[doc(hidden)]
pub extern crate soft_ascii_string;
extern crate quoted_string;
#[macro_use]
extern crate failure;
extern crate owning_ref;
#[macro_use]
extern crate nom;
extern crate chrono;
#[cfg_attr(test, macro_use)]
extern crate vec1;
extern crate total_order_multi_map;
//FIXME[rust/macros use private] remove pub re-export
#[cfg_attr(test, macro_use)]
#[doc(hidden)]
pub extern crate mail_internals as __internals;

#[cfg(feature="serde")]
extern crate serde;
#[cfg(all(test, feature="serde"))]
extern crate serde_test;

#[cfg(all(test, not(feature="traceing")))]
compile_error! { "testing needs feature `traceing` to be enabled" }

#[cfg(all(feature="serde", not(feature="serde-impl")))]
compile_error! { "you need to enable \"serde-impl\" when you enable \"serde\"" }

#[macro_use]
mod macros;
mod name;
#[macro_use]
pub mod error;
mod header;
mod convert;
pub mod data;
#[macro_use]
mod header_macro;
#[macro_use]
pub mod map;
pub mod header_components;
pub mod headers;

pub use self::name::*;
pub use self::header::*;
pub use self::convert::*;
pub use self::header_macro::*;
pub use self::map::HeaderMap;


// I can not reexport a private think anymore, so I need to reexport the
// extern crate and then make the normal name available, too
use __internals as internals;