Start development sprint 3.

src/database/permissions/channel.rs

@@ -0,0 +1,33 @@
+use crate::database::*;
+use num_enum::TryFromPrimitive;
+use std::ops;
+
+#[derive(Debug, PartialEq, Eq, TryFromPrimitive, Copy, Clone)]
+#[repr(u32)]
+pub enum ChannelPermission {
+    View = 1,
+    SendMessage = 2,
+}
+
+bitfield! {
+    pub struct ChannelPermissions(MSB0 [u32]);
+    u32;
+    pub get_view, _: 31;
+    pub get_send_message, _: 30;
+}
+
+impl_op_ex!(+ |a: &ChannelPermission, b: &ChannelPermission| -> u32 { *a as u32 | *b as u32 });
+impl_op_ex_commutative!(+ |a: &u32, b: &ChannelPermission| -> u32 { *a | *b as u32 });
+
+pub async fn calculate(user: &User, target: &Channel) -> ChannelPermissions<[u32; 1]> {
+    match target {
+        Channel::SavedMessages { user: owner, .. } => {
+            if &user.id == owner {
+                ChannelPermissions([ ChannelPermission::View + ChannelPermission::SendMessage ])
+            } else {
+                ChannelPermissions([ 0 ])
+            }
+        }
+        _ => unreachable!()
+    }
+}

src/database/permissions/mod.rs

@@ -1,3 +1,4 @@
 pub mod user;
+pub mod channel;
 
 pub use user::get_relationship;