feat(builtins): introduce allow!-macro

src/builtins/mod.rs

@@ -1,5 +1,171 @@
 //! Built-in [`RuleSet`](crate::RuleSet)s
 
+/// Implement `allow_*`-methods.
+///
+/// See e.g. `time.mod` and `user_id.mod`.
+///
+/// NOTE: Follow the `@labels`.
+macro_rules! allow {
+    (
+        $(#[$attr:meta])*
+        $vis:vis fn $method:ident($self:ident) {
+            $($inner:tt)*
+        }
+    ) => {
+        allow! {
+            @impl_outer ()
+            $(#[$attr])*
+            $vis fn $method($self) -> Self {
+                $($inner)*
+            }
+        }
+    };
+
+    (
+        $(#[$attr:meta])*
+        $vis:vis unsafe fn $method:ident($self:ident) {
+            $($inner:tt)*
+        }
+    ) => {
+        allow! {
+            @impl_outer (unsafe)
+            $(#[$attr])*
+            $vis fn $method($self) -> YesReally<Self> {
+                $($inner)*
+            }
+        }
+    };
+
+    (
+        $(
+            $(#[$attr:meta])*
+            $vis:vis $($outer:ident)+($self:ident) { $($inner:tt)* }
+        )*
+    ) => {
+        $(
+            allow! {
+                $(#[$attr])*
+                $vis $($outer)+($self) {
+                    $($inner)*
+                }
+            }
+        )*
+    };
+
+    (
+        @impl_outer ($($unsafe:ident)?)
+        $(#[$outer_attr:meta])*
+        $outer_vis:vis fn $outer_method:ident($self:ident) -> $output:ty {
+            $(
+                $(#[$inner_attr:meta])*
+                $inner_vis:vis $($inner:ident)+ ($syscall:ident);
+            )*
+        }
+    ) => {
+        $(#[$outer_attr])*
+        $outer_vis fn $outer_method($self) -> $output {
+            allow! { @call_inner_block $($unsafe)? $self { $(($($inner)+))* } }
+        }
+
+        allow! {
+            @impl_inner_block $($unsafe)? {
+                $(
+                    $(#[$inner_attr])*
+                    $inner_vis $($inner)+ ($syscall)
+                )*
+            }
+        }
+    };
+
+    ( @call_inner_block $self:ident { $(($($inner:ident)+))* } ) => {
+        let this = $self;
+        $( allow! { @call_inner this: $($inner)+ } )*
+        this
+    };
+
+    ( @call_inner_block unsafe $self:ident { $(($($inner:ident)+))* } ) => {
+        let this = $self;
+        $( allow! { @call_inner this: unsafe $($inner)+ } )*
+        YesReally::new(this)
+    };
+
+    ( @call_inner $this:ident: fn $method:ident ) => {
+        let $this = $this.$method();
+    };
+
+    ( @call_inner $this:ident: unsafe $(unsafe)? fn $method:ident ) => {
+        let $this = $this.$method().yes_really();
+    };
+
+    (
+        @impl_inner_block {
+            $(
+                $(#[$attr:meta])*
+                $vis:vis $($inner:ident)+($syscall:ident)
+            )*
+        }
+    ) => {
+        $(
+            allow! {
+                @impl_inner
+                $(#[$attr])*
+                $vis $($inner)+($syscall)
+            }
+        )*
+    };
+
+    (
+        @impl_inner_block
+        unsafe {
+            $(
+                $(#[$attr:meta])*
+                $vis:vis $(unsafe)? fn $method:ident($syscall:ident)
+            )*
+        }
+    ) => {
+        $(
+            allow! {
+                @impl_inner
+                $(#[$attr])*
+                $vis unsafe fn $method($syscall)
+            }
+        )*
+    };
+
+    (
+        @impl_inner
+        $(#[$attr:meta])*
+        $vis:vis fn $method:ident($syscall:ident)
+    ) => {
+        $(#[$attr])*
+        $vis fn $method(mut self) -> Self {
+            let _ = self.syscalls.insert(syscalls::Sysno::$syscall);
+            self
+        }
+    };
+
+    (
+        @impl_inner
+        $(#[$attr:meta])*
+        $vis:vis unsafe fn $method:ident($syscall:ident)
+    ) => {
+        $(#[$attr])*
+        $vis fn $method(mut self) -> YesReally<Self> {
+            let _ = self.syscalls.insert(syscalls::Sysno::$syscall);
+            YesReally::new(self)
+        }
+    };
+}
+
+pub mod basic;
+pub mod danger_zone;
+pub mod network;
+pub mod pipes;
+pub mod systemio;
+pub mod time;
+
+pub use {basic::BasicCapabilities, network::Networking, systemio::SystemIO, time::Time};
+
 /// A struct whose purpose is to make you read the documentation for the function you're calling.
 /// If you're reading this, go read the documentation for the function that is returning this
 /// object.
@@ -16,23 +182,6 @@ impl<T> YesReally<T> {
 
     /// Make a [`YesReally`].
     pub fn new(inner: T) -> YesReally<T> {
-        YesReally {
-            inner,
-        }
+        YesReally { inner }
     }
 }
-
-pub mod basic;
-pub use basic::BasicCapabilities;
-
-pub mod systemio;
-pub use systemio::SystemIO;
-
-pub mod network;
-pub use network::Networking;
-
-pub mod time;
-pub use time::Time;
-
-pub mod danger_zone;
-pub mod pipes;