Restructure modules

Modules are now separated into a fashion where the library can be used
for most use cases, without needing to compile the rest.

The core of serenity, with no features enabled, contains only the
struct (model) definitions, constants, and prelude. Models do not have
most functions compiled in, as that is separated into the `model`
feature.

The `client` module has been split into 3 modules: `client`, `gateway`,
and `http`.

`http` contains functions to interact with the REST API. `gateway`
contains the Shard to interact with the gateway, requiring `http` for
retrieving the gateway URL. `client` requires both of the other features
and acts as an abstracted interface over both the gateway and REST APIs,
handling the event loop.

The `builder` module has been separated from `utils`, and can now be
optionally compiled in. It and the `http` feature are required by the
`model` feature due to a large number of methods requiring access to
them.

`utils` now contains a number of utilities, such as the Colour struct, the
`MessageBuilder`, and mention parsing functions.

Each of the original `ext` modules are still featured, with `cache` not
requiring any feature to be enabled, `framework` requiring the `client`,
`model`, and `utils`, and `voice` requiring `gateway`.

In total the features and their requirements are:

- `builder`: none
- `cache`: none
- `client`: `gateway`, `http`
- `framework`: `client`, `model`, `utils`
- `gateway`: `http`
- `http`: none
- `model`: `builder`, `http`
- `utils`: none
- `voice`: `gateway`

The default features are `builder`, `cache`, `client`, `framework`,
`gateway`, `model`, `http`, and `utils`.

To help with forwards compatibility, modules have been re-exported from
their original locations.

1 files changed, 52 insertions, 46 deletions

diff --git a/src/model/guild/mod.rs b/src/model/guild/mod.rs
index de2c646..a3d37d0 100644
--- a/src/model/guild/mod.rs
+++ b/src/model/guild/mod.rs
@@ -17,13 +17,15 @@ pub use self::role::*;
 use serde::de::Error as DeError;
 use serde_json;
 use super::utils::*;
-use ::client::rest;
 use ::constants::LARGE_THRESHOLD;
 use ::model::*;
-use ::utils::builder::{EditGuild, EditMember, EditRole};
 
 #[cfg(feature="cache")]
-use ::client::CACHE;
+use ::CACHE;
+#[cfg(feature="http")]
+use ::http;
+#[cfg(feature="model")]
+use ::builder::{EditGuild, EditMember, EditRole};
 
 /// A representation of a banning of a user.
 #[derive(Clone, Debug, Deserialize)]
@@ -118,12 +120,13 @@ pub struct Guild {
     pub voice_states: HashMap<UserId, VoiceState>,
 }
 
+#[cfg(feature="model")]
 impl Guild {
     #[cfg(feature="cache")]
     fn has_perms(&self, mut permissions: Permissions) -> Result<bool> {
         let member = match self.members.get(&CACHE.read().unwrap().user.id) {
             Some(member) => member,
-            None => return Err(Error::Client(ClientError::ItemMissing)),
+            None => return Err(Error::Model(ModelError::ItemMissing)),
         };
 
         let perms = self.permissions_for(ChannelId(self.id.0), member.user.read().unwrap().id);
@@ -150,21 +153,21 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// Returns a [`ClientError::InvalidPermissions`] if the current user does
+    /// Returns a [`ModelError::InvalidPermissions`] if the current user does
     /// not have permission to perform bans.
     ///
-    /// Returns a [`ClientError::DeleteMessageDaysAmount`] if the number of
+    /// Returns a [`ModelError::DeleteMessageDaysAmount`] if the number of
     /// days' worth of messages to delete is over the maximum.
     ///
-    /// [`ClientError::DeleteMessageDaysAmount`]: ../client/enum.ClientError.html#variant.DeleteMessageDaysAmount
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::DeleteMessageDaysAmount`]: enum.ModelError.html#variant.DeleteMessageDaysAmount
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [`Guild::ban`]: struct.Guild.html#method.ban
     /// [`User`]: struct.User.html
     /// [Ban Members]: permissions/constant.BAN_MEMBERS.html
     pub fn ban<U: Into<UserId>>(&self, user: U, delete_message_days: u8)
         -> Result<()> {
         if delete_message_days > 7 {
-            return Err(Error::Client(ClientError::DeleteMessageDaysAmount(delete_message_days)));
+            return Err(Error::Model(ModelError::DeleteMessageDaysAmount(delete_message_days)));
         }
 
         #[cfg(feature="cache")]
@@ -172,7 +175,7 @@ impl Guild {
             let req = permissions::BAN_MEMBERS;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -185,11 +188,11 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
     /// [`Ban`]: struct.Ban.html
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [Ban Members]: permissions/constant.BAN_MEMBERS.html
     pub fn bans(&self) -> Result<Vec<Ban>> {
         #[cfg(feature="cache")]
@@ -197,7 +200,7 @@ impl Guild {
             let req = permissions::BAN_MEMBERS;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -234,7 +237,7 @@ impl Guild {
     ///
     /// [`Guild`]: struct.Guild.html
     /// [`PartialGuild`]: struct.PartialGuild.html
-    /// [`Shard`]: ../client/gateway/struct.Shard.html
+    /// [`Shard`]: ../gateway/struct.Shard.html
     /// [US West region]: enum.Region.html#variant.UsWest
     /// [whitelist]: https://discordapp.com/developers/docs/resources/guild#create-guild
     pub fn create(name: &str, region: Region, icon: Option<&str>) -> Result<PartialGuild> {
@@ -244,7 +247,7 @@ impl Guild {
             "region": region.name(),
         });
 
-        rest::create_guild(&map)
+        http::create_guild(&map)
     }
 
     /// Creates a new [`Channel`] in the guild.
@@ -263,11 +266,11 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
     /// [`Channel`]: struct.Channel.html
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [Manage Channels]: permissions/constant.MANAGE_CHANNELS.html
     pub fn create_channel(&mut self, name: &str, kind: ChannelType) -> Result<GuildChannel> {
         #[cfg(feature="cache")]
@@ -275,7 +278,7 @@ impl Guild {
             let req = permissions::MANAGE_CHANNELS;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -298,8 +301,8 @@ impl Guild {
     /// how to read an image from the filesystem and encode it as base64. Most
     /// of the example can be applied similarly for this method.
     ///
-    /// [`EditProfile::avatar`]: ../utils/builder/struct.EditProfile.html#method.avatar
-    /// [`utils::read_image`]: ../utils/fn.read_image.html
+    /// [`EditProfile::avatar`]: ../builder/struct.EditProfile.html#method.avatar
+    /// [`utils::read_image`]: ../fn.read_image.html
     /// [Manage Emojis]: permissions/constant.MANAGE_EMOJIS.html
     #[inline]
     pub fn create_emoji(&self, name: &str, image: &str) -> Result<Emoji> {
@@ -333,10 +336,10 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [`Context::create_role`]: ../client/struct.Context.html#method.create_role
     /// [`Role`]: struct.Role.html
     /// [Manage Roles]: permissions/constant.MANAGE_ROLES.html
@@ -347,7 +350,7 @@ impl Guild {
             let req = permissions::MANAGE_ROLES;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -361,17 +364,17 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, then returns a [`ClientError::InvalidUser`]
+    /// If the `cache` is enabled, then returns a [`ModelError::InvalidUser`]
     /// if the current user is not the guild owner.
     ///
-    /// [`ClientError::InvalidUser`]: ../client/enum.ClientError.html#variant.InvalidUser
+    /// [`ModelError::InvalidUser`]: enum.ModelError.html#variant.InvalidUser
     pub fn delete(&self) -> Result<PartialGuild> {
         #[cfg(feature="cache")]
         {
             if self.owner_id != CACHE.read().unwrap().user.id {
                 let req = permissions::MANAGE_GUILD;
 
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -437,10 +440,10 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [`Context::edit_guild`]: ../client/struct.Context.html#method.edit_guild
     /// [Manage Guild]: permissions/constant.MANAGE_GUILD.html
     pub fn edit<F>(&mut self, f: F) -> Result<()>
@@ -450,7 +453,7 @@ impl Guild {
             let req = permissions::MANAGE_GUILD;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -518,11 +521,11 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to change their own
     /// nickname.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [Change Nickname]: permissions/constant.CHANGE_NICKNAME.html
     pub fn edit_nickname(&self, new_nickname: Option<&str>) -> Result<()> {
         #[cfg(feature="cache")]
@@ -530,7 +533,7 @@ impl Guild {
             let req = permissions::CHANGE_NICKNAME;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -604,10 +607,10 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [Manage Guild]: permissions/constant.MANAGE_GUILD.html
     pub fn invites(&self) -> Result<Vec<RichInvite>> {
         #[cfg(feature="cache")]
@@ -615,7 +618,7 @@ impl Guild {
             let req = permissions::MANAGE_GUILD;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -850,10 +853,10 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [`GuildPrune`]: struct.GuildPrune.html
     /// [`Member`]: struct.Member.html
     /// [Kick Members]: permissions/constant.KICK_MEMBERS.html
@@ -863,7 +866,7 @@ impl Guild {
             let req = permissions::KICK_MEMBERS;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -880,7 +883,7 @@ impl Guild {
     /// total, consider using [`utils::shard_id`].
     ///
     /// [`utils::shard_id`]: ../utils/fn.shard_id.html
-    #[cfg(feature="cache")]
+    #[cfg(all(feature="cache", feature="utils"))]
     #[inline]
     pub fn shard_id(&self) -> u64 {
         self.id.shard_id()
@@ -906,7 +909,7 @@ impl Guild {
     ///
     /// assert_eq!(guild.shard_id(17), 7);
     /// ```
-    #[cfg(not(feature="cache"))]
+    #[cfg(all(feature="utils", not(feature="cache")))]
     #[inline]
     pub fn shard_id(&self, shard_count: u64) -> u64 {
         self.id.shard_id(shard_count)
@@ -936,10 +939,10 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [`GuildPrune`]: struct.GuildPrune.html
     /// [`Member`]: struct.Member.html
     /// [Kick Members]: permissions/constant.KICK_MEMBERS.html
@@ -949,7 +952,7 @@ impl Guild {
             let req = permissions::KICK_MEMBERS;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -962,10 +965,10 @@ impl Guild {
     ///
     /// # Errors
     ///
-    /// If the `cache` is enabled, returns a [`ClientError::InvalidPermissions`]
+    /// If the `cache` is enabled, returns a [`ModelError::InvalidPermissions`]
     /// if the current user does not have permission to perform bans.
     ///
-    /// [`ClientError::InvalidPermissions`]: ../client/enum.ClientError.html#variant.InvalidPermissions
+    /// [`ModelError::InvalidPermissions`]: enum.ModelError.html#variant.InvalidPermissions
     /// [`User`]: struct.User.html
     /// [Ban Members]: permissions/constant.BAN_MEMBERS.html
     pub fn unban<U: Into<UserId>>(&self, user_id: U) -> Result<()> {
@@ -974,7 +977,7 @@ impl Guild {
             let req = permissions::BAN_MEMBERS;
 
             if !self.has_perms(req)? {
-                return Err(Error::Client(ClientError::InvalidPermissions(req)));
+                return Err(Error::Model(ModelError::InvalidPermissions(req)));
             }
         }
 
@@ -1258,6 +1261,7 @@ pub struct GuildInfo {
     pub permissions: Permissions,
 }
 
+#[cfg(any(feature="model", feature="utils"))]
 impl GuildInfo {
     /// Returns the formatted URL of the guild's icon, if the guild has an icon.
     pub fn icon_url(&self) -> Option<String> {
@@ -1284,6 +1288,7 @@ impl From<u64> for GuildContainer {
     }
 }
 
+#[cfg(feature="model")]
 impl InviteGuild {
     /// Returns the formatted URL of the guild's splash image, if one exists.
     pub fn splash_url(&self) -> Option<String> {
@@ -1314,6 +1319,7 @@ pub enum GuildStatus {
     Offline(GuildUnavailable),
 }
 
+#[cfg(feature="model")]
 impl GuildStatus {
     /// Retrieves the Id of the inner [`Guild`].
     ///