add project & mock macro

1 files changed, 245 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..9f404f1
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,245 @@
+#[macro_export]
+macro_rules! mock {
+    (
+        $mock: ident;
+
+        impl $mocked_trait: ident for $mocked_trait_target: ident {
+            $(
+                fn $func: ident$(<
+                    $($type_param: tt$(: ($($type_param_bound: tt +)+))?),*
+                >)?(
+                    self: ($($self_type: tt)+),
+                    $($func_param: ident: $func_param_type: ty),*
+                )$( -> $return_type: ty)?
+                    $(where ($($where: tt)*))?;
+            )*
+        }
+    ) => {
+        $crate::__private::paste! {
+        mod [<__ $mock>] {
+        use super::*;
+
+        pub struct $mock {
+            $(
+                [<$func _expectations>]: std::collections::HashMap<
+                    Vec<$crate::__private::type_id::TypeID>,
+                    [<$mock Expectation _ $func>]$(<$($crate::__to_unit!($type_param)),*>)?
+                >,
+            )*
+        }
+
+        impl $mock
+        {
+            pub fn new() -> Self
+            {
+                Self {
+                    $(
+                        [<$func _expectations>]: std::collections::HashMap::new()
+                    ),*
+                }
+            }
+
+            $(
+                #[allow(unused)]
+                pub(crate) fn [<expect_ $func>]$(<
+                    $($type_param$(: $($type_param_bound +)*)?),*
+                >)?(&mut self)
+                    -> &mut [<$mock Expectation _ $func>]$(<$($type_param),*>)?
+                $(where $($where)*)?
+                {
+                    let ids = vec![
+                        $($($crate::__private::type_id::TypeID::of::<$type_param>()),*)?
+                    ];
+
+                    let expectation =
+                        [<$mock Expectation _ $func>]$(::<$($type_param),*>)?::new()
+                            .strip_type_params();
+
+                    self.[<$func _expectations>].insert(ids.clone(), expectation);
+
+                    self.[<$func _expectations>]
+                        .get_mut(&ids)
+                        .unwrap()
+                        .with_type_params_mut()
+                }
+            )*
+        }
+
+        impl $mocked_trait for $mock {
+            $(
+                fn $func$(<$($type_param$(: $($type_param_bound +)+)?),*>)?(
+                    self: $($self_type)+,
+                    $($func_param: $func_param_type),*
+                )$( -> $return_type)?
+                $(where $($where)*)?
+                {
+                    let ids = vec![
+                        $($($crate::__private::type_id::TypeID::of::<$type_param>()),*)?
+                    ];
+
+                    let expectation = self
+                        .[<$func _expectations>]
+                        .get(&ids)
+                        .expect(concat!(
+                            "No expectation found for function ",
+                            stringify!($func)
+                        ))
+                        .with_type_params$(::<$($type_param),*>)?();
+
+                    let Some(returning) = &expectation.returning else {
+                        panic!(concat!(
+                            "Expectation for function",
+                            stringify!($func),
+                            " is missing a function to call")
+                        );
+                    };
+
+                    returning(self, $($func_param),*)
+                }
+            )*
+        }
+
+        $(
+            #[allow(non_camel_case_types, non_snake_case)]
+            pub struct [<$mock Expectation _ $func>]$(<$($type_param),*>)? {
+                returning: Option<
+                    fn(
+                        $crate::__replace_ref_type!($($self_type)*, $mock),
+                        $($func_param_type),*
+                    )$( -> $return_type)?>,
+
+                $(
+                    $([<$type_param _phantom>]: std::marker::PhantomData<$type_param>,)*
+                )?
+            }
+
+            impl$(<$($type_param),*>)? [<$mock Expectation _ $func>]$(<
+                $($type_param),*
+            >)? {
+                #[allow(unused)]
+                fn new() -> Self {
+                    Self {
+                        returning: None,
+                        $(
+                            $([<$type_param _phantom>]: std::marker::PhantomData,)*
+                        )?
+                    }
+                }
+
+                #[allow(unused)]
+                pub fn returning(
+                    &mut self,
+                    func: fn(
+                        $crate::__replace_ref_type!($($self_type)*, $mock),
+                        $($func_param_type),*
+                    )$( -> $return_type)?
+                ) -> &mut Self
+                {
+                    self.returning = Some(func);
+
+                    self
+                }
+
+                #[allow(unused)]
+                fn strip_type_params(
+                    self,
+                ) -> [<$mock Expectation _ $func>]$(<$($crate::__to_unit!($type_param)),*>)?
+                {
+                    $crate::__if_empty_else!(($($($type_param)*)?); {
+                        // No type parameters are present
+                        self
+                    }, {
+                        // Type parameters are present
+                        unsafe { std::mem::transmute(self) }
+                    })
+
+                }
+            }
+
+            impl [<$mock Expectation _ $func>]$(<$($crate::__to_unit!($type_param)),*>)? {
+                fn with_type_params$(<$($type_param),*>)?(
+                    &self,
+                ) -> &[<$mock Expectation _ $func>]$(<$($type_param),*>)?
+                {
+                    unsafe { &*(self as *const Self).cast() }
+                }
+
+                #[allow(unused)]
+                fn with_type_params_mut$(<$($type_param),*>)?(
+                    &mut self,
+                ) -> &mut [<$mock Expectation _ $func>]$(<$($type_param),*>)?
+                {
+                    unsafe { &mut *(self as *mut Self).cast() }
+                }
+            }
+        )*
+        }
+
+        use [<__ $mock>]::$mock;
+        }
+    };
+}
+
+#[doc(hidden)]
+pub mod __private
+{
+    pub use paste::paste;
+
+    pub mod type_id
+    {
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+        pub struct TypeID
+        {
+            id: usize,
+        }
+
+        impl TypeID
+        {
+            #[inline]
+            pub fn of<T>() -> Self
+            {
+                Self {
+                    id: Self::of::<T> as usize,
+                }
+            }
+        }
+    }
+
+    #[macro_export]
+    #[doc(hidden)]
+    macro_rules! __to_unit {
+        ($anything: tt) => {
+            ()
+        };
+    }
+
+    #[macro_export]
+    #[doc(hidden)]
+    macro_rules! __replace_ref_type {
+        (&$old_type: tt, $new_type: tt) => {
+            &$new_type
+        };
+
+        (&mut $old_type: tt, $new_type: tt) => {
+            &mut $new_type
+        };
+    }
+
+    #[macro_export]
+    #[doc(hidden)]
+    macro_rules! __if_empty_else {
+        (($($input: tt)*); $if_empty: block, $else: block) => {
+            $crate::__if_empty_else!(@($($input)*); $if_empty, $else)
+        };
+
+        // Empty
+        (@(); $if_empty: block, $else: block) => {
+            $if_empty
+        };
+
+        // Not empty
+        (@($($input: tt)+); $if_empty: block, $else: block) => {
+            $else
+        };
+    }
+}