From a4f1a496bd8535919a02540196337d44d3276345 Mon Sep 17 00:00:00 2001
From: Andras Schmelczer <andras@schmelczer.dev>
Date: Sun, 22 Jun 2025 09:48:56 +0100
Subject: [PATCH] Remove merge context

---
 src/operation_transformation.rs               |  1 -
 src/operation_transformation/edited_text.rs   | 24 ++----
 src/operation_transformation/merge_context.rs | 75 -------------------
 3 files changed, 6 insertions(+), 94 deletions(-)
 delete mode 100644 src/operation_transformation/merge_context.rs

diff --git a/src/operation_transformation.rs b/src/operation_transformation.rs
index 9fd5a5d..c971229 100644
--- a/src/operation_transformation.rs
+++ b/src/operation_transformation.rs
@@ -1,6 +1,5 @@
 mod cursor;
 mod edited_text;
-mod merge_context;
 mod operation;
 mod ordered_operation;
 mod utils;
diff --git a/src/operation_transformation/edited_text.rs b/src/operation_transformation/edited_text.rs
index 6aea48e..4190157 100644
--- a/src/operation_transformation/edited_text.rs
+++ b/src/operation_transformation/edited_text.rs
@@ -4,9 +4,8 @@ use serde::{Deserialize, Serialize};
 use super::{CursorPosition, Operation, TextWithCursors, ordered_operation::OrderedOperation};
 use crate::{
     diffs::{myers::diff, raw_operation::RawOperation},
-    operation_transformation::{
-        merge_context::MergeContext,
-        utils::{cook_operations::cook_operations, elongate_operations::elongate_operations},
+    operation_transformation::utils::{
+        cook_operations::cook_operations, elongate_operations::elongate_operations,
     },
     tokenizer::{Tokenizer, word_tokenizer::word_tokenizer},
     utils::{side::Side, string_builder::StringBuilder},
@@ -99,9 +98,6 @@ where
             "`EditedText`-s must be derived from the same text to be mergable"
         );
 
-        let mut left_merge_context = MergeContext::default();
-        let mut right_merge_context = MergeContext::default();
-
         let mut merged_cursors = Vec::with_capacity(self.cursors.len() + other.cursors.len());
         let mut left_cursors = self.cursors.into_iter().peekable();
         let mut right_cursors = other.cursors.into_iter().peekable();
@@ -148,12 +144,8 @@ where
             let original_length = operation.len() as i64;
             let result = match side {
                 Side::Left => {
-                    let result = operation.merge_operations_with_context(
-                        order,
-                        &mut right_merge_context,
-                        &mut left_merge_context,
-                        maybe_other_operation,
-                    );
+                    let result =
+                        operation.merge_operations_with_context(order, maybe_other_operation);
 
                     if let Some(ref op @ (Operation::Insert { .. } | Operation::Equal { .. })) =
                         result
@@ -182,12 +174,8 @@ where
                     result
                 }
                 Side::Right => {
-                    let result = operation.merge_operations_with_context(
-                        order,
-                        &mut left_merge_context,
-                        &mut right_merge_context,
-                        maybe_other_operation,
-                    );
+                    let result =
+                        operation.merge_operations_with_context(order, maybe_other_operation);
 
                     if let Some(ref op @ (Operation::Insert { .. } | Operation::Equal { .. })) =
                         result
diff --git a/src/operation_transformation/merge_context.rs b/src/operation_transformation/merge_context.rs
deleted file mode 100644
index b40d2f3..0000000
--- a/src/operation_transformation/merge_context.rs
+++ /dev/null
@@ -1,75 +0,0 @@
-use core::fmt::Debug;
-
-use crate::operation_transformation::Operation;
-
-#[derive(Clone, Debug)]
-pub struct MergeContext<T>
-where
-    T: PartialEq + Clone + std::fmt::Debug,
-{
-    last_operation: Option<Operation<T>>,
-    pub shift: i64,
-}
-
-impl<T> Default for MergeContext<T>
-where
-    T: PartialEq + Clone + std::fmt::Debug,
-{
-    fn default() -> Self {
-        MergeContext {
-            last_operation: None,
-            shift: 0,
-        }
-    }
-}
-
-impl<T> MergeContext<T>
-where
-    T: PartialEq + Clone + std::fmt::Debug,
-{
-    pub fn last_operation(&self) -> Option<&Operation<T>> { self.last_operation.as_ref() }
-
-    pub fn replace_last_operation(&mut self, operation: Option<Operation<T>>) {
-        self.last_operation = operation;
-    }
-
-    /// Replace the last delete operation (if there was one) with a new one
-    /// while applying it to the `shift` in case the last operation
-    /// was a delete.
-    pub fn consume_and_replace_last_operation(&mut self, operation: Option<Operation<T>>) {
-        if let Some(Operation::Delete {
-            deleted_character_count,
-            ..
-        }) = self.last_operation.take()
-        {
-            self.shift -= deleted_character_count as i64;
-        }
-
-        self.last_operation = operation;
-    }
-
-    /// Remove the last operation (if there was one) in case it is behind the
-    /// threshold operation. This updates the `shift` in case the last operation
-    /// was a delete.
-    pub fn consume_last_operation_if_it_is_too_behind(&mut self, threshold_index: i64) {
-        match self.last_operation.as_ref() {
-            Some(
-                op @ Operation::Delete {
-                    deleted_character_count,
-                    ..
-                },
-            ) => {
-                if threshold_index + self.shift >= op.end_index() as i64 {
-                    self.shift -= *deleted_character_count as i64;
-                    self.last_operation = None;
-                }
-            }
-            Some(op @ Operation::Insert { .. }) | Some(op @ Operation::Equal { .. }) => {
-                if threshold_index + self.shift - op.len() as i64 >= op.end_index() as i64 {
-                    self.last_operation = None;
-                }
-            }
-            _ => {}
-        }
-    }
-}