From ad7a1c54ce063192998a8fdff1042a7aa7277347 Mon Sep 17 00:00:00 2001
From: Zixuan Chen <remch183@outlook.com>
Date: Fri, 15 Jul 2022 20:32:35 +0800
Subject: [PATCH] refactor: better insert content trait

---
 crates/loro-core/src/op/insert_content.rs | 40 ++++++++++++++++++-----
 crates/rle/src/rle.rs                     |  2 +-
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/crates/loro-core/src/op/insert_content.rs b/crates/loro-core/src/op/insert_content.rs
index 53916431..c139612d 100644
--- a/crates/loro-core/src/op/insert_content.rs
+++ b/crates/loro-core/src/op/insert_content.rs
@@ -4,32 +4,56 @@ use crate::id::ID;
 use rle::{HasLength, Mergable, Sliceable};
 #[derive(PartialEq, Eq, Debug, Clone, Copy)]
 pub enum ContentTypeID {
+    Container,
     Text,
     Custom(u16),
 }
 
-pub trait MergeableInsertContent {
+pub trait MergeableContent {
     fn is_mergable_content(&self, other: &dyn InsertContent) -> bool;
     fn merge_content(&mut self, other: &dyn InsertContent);
 }
 
-pub trait InsertContent: HasLength + std::fmt::Debug + Any + MergeableInsertContent {
-    fn id(&self) -> ContentTypeID;
-    fn slice(&self, from: usize, to: usize) -> Box<dyn InsertContent>;
+pub trait SliceableContent {
+    fn slice_content(&self, from: usize, to: usize) -> Box<dyn InsertContent>;
+}
+
+pub trait CloneContent {
     fn clone_content(&self) -> Box<dyn InsertContent>;
 }
 
-impl<T: Mergable + Any> MergeableInsertContent for T {
+pub trait InsertContent:
+    HasLength + std::fmt::Debug + Any + MergeableContent + SliceableContent + CloneContent
+{
+    fn id(&self) -> ContentTypeID;
+}
+
+impl<T: Sliceable + InsertContent> SliceableContent for T {
+    fn slice_content(&self, from: usize, to: usize) -> Box<dyn InsertContent> {
+        Box::new(self.slice(from, to))
+    }
+}
+
+impl<T: Clone + InsertContent> CloneContent for T {
+    fn clone_content(&self) -> Box<dyn InsertContent> {
+        Box::new(self.clone())
+    }
+}
+
+impl<T: Mergable + Any> MergeableContent for T {
     fn is_mergable_content(&self, other: &dyn InsertContent) -> bool {
         if self.type_id() == other.type_id() {
-            self.is_mergable(unsafe { &*(other as *const dyn Any as *const T) }, &())
+            self.is_mergable(
+                unsafe { &*(other as *const dyn InsertContent as *const T) },
+                &(),
+            )
         } else {
             false
         }
     }
 
     fn merge_content(&mut self, other: &dyn InsertContent) {
-        let other = unsafe { &*(other as *const dyn Any as *const T) };
+        let other = unsafe { &*(other as *const dyn InsertContent as *const T) };
         self.merge(other, &());
     }
 }
@@ -40,7 +64,7 @@ pub mod content {
         let t = TypeId::of::<T>();
         let concrete = content.type_id();
         if t == concrete {
-            Some(unsafe { &*(content as *const dyn Any as *const T) })
+            Some(unsafe { &*(content as *const dyn InsertContent as *const T) })
         } else {
             None
         }
diff --git a/crates/rle/src/rle.rs b/crates/rle/src/rle.rs
index 885cf109..2cd25157 100644
--- a/crates/rle/src/rle.rs
+++ b/crates/rle/src/rle.rs
@@ -133,7 +133,7 @@ impl<T: Mergable<Cfg> + HasLength, Cfg> RleVec<T, Cfg> {
     }
 
     pub fn slice_merged(&self, range: Range<usize>) -> &[T] {
-        todo!()
+        &self.vec[range]
     }
 }