check size when applying operations

src-tauri/src/deltas/operations/operations.rs

@@ -1,3 +1,4 @@
+use anyhow::Result;
 use difference::{Changeset, Difference};
 use serde::{Deserialize, Serialize};
 
@@ -11,13 +12,40 @@ pub enum Operation {
 }
 
 impl Operation {
-    pub fn apply(&self, text: &mut Vec<char>) {
+    pub fn apply(&self, text: &mut Vec<char>) -> Result<()> {
         match self {
             Operation::Insert((index, chunk)) => {
-                text.splice(*index as usize..*index as usize, chunk.chars());
+                if *index as usize > text.len() {
+                    Err(anyhow::anyhow!(
+                        "Index out of bounds, {} > {}",
+                        index,
+                        text.len()
+                    ))
+                } else if *index as usize == text.len() {
+                    text.extend(chunk.chars());
+                    Ok(())
+                } else {
+                    text.splice(*index as usize..*index as usize, chunk.chars());
+                    Ok(())
+                }
             }
             Operation::Delete((index, len)) => {
-                text.splice(*index as usize..(*index + *len) as usize, "".chars());
+                if *index as usize > text.len() {
+                    Err(anyhow::anyhow!(
+                        "Index out of bounds, {} > {}",
+                        index,
+                        text.len()
+                    ))
+                } else if *index as usize + *len as usize > text.len() {
+                    Err(anyhow::anyhow!(
+                        "Index + length out of bounds, {} > {}",
+                        index + len,
+                        text.len()
+                    ))
+                } else {
+                    text.splice(*index as usize..(*index + *len) as usize, "".chars());
+                    Ok(())
+                }
             }
         }
     }

src-tauri/src/deltas/text_document.rs

@@ -1,6 +1,6 @@
-use std::time::SystemTime;
-
 use super::{deltas, operations};
+use anyhow::Result;
+use std::time::SystemTime;
 
 #[derive(Debug, Clone, Default)]
 pub struct TextDocument {
@@ -8,20 +8,21 @@ pub struct TextDocument {
     deltas: Vec<deltas::Delta>,
 }
 
-fn apply_deltas(doc: &mut Vec<char>, deltas: &Vec<deltas::Delta>) {
+fn apply_deltas(doc: &mut Vec<char>, deltas: &Vec<deltas::Delta>) -> Result<()> {
     for delta in deltas {
         for operation in &delta.operations {
-            operation.apply(doc);
+            operation.apply(doc)?;
         }
     }
+    Ok(())
 }
 
 impl TextDocument {
     // creates a new text document from a deltas.
-    pub fn from_deltas(deltas: Vec<deltas::Delta>) -> TextDocument {
+    pub fn from_deltas(deltas: Vec<deltas::Delta>) -> Result<TextDocument> {
         let mut doc = vec![];
-        apply_deltas(&mut doc, &deltas);
+        apply_deltas(&mut doc, &deltas)?;
-        TextDocument { doc, deltas }
+        Ok(TextDocument { doc, deltas })
     }
 
     pub fn get_deltas(&self) -> Vec<deltas::Delta> {
@@ -29,18 +30,18 @@ impl TextDocument {
     }
 
     // returns a text document where internal state is seeded with value, and deltas are applied.
-    pub fn new(value: &str, deltas: Vec<deltas::Delta>) -> TextDocument {
+    pub fn new(value: &str, deltas: Vec<deltas::Delta>) -> Result<TextDocument> {
         let mut all_deltas = vec![deltas::Delta {
             operations: operations::get_delta_operations("", value),
             timestamp_ms: 0,
         }];
         all_deltas.append(&mut deltas.clone());
         let mut doc = vec![];
-        apply_deltas(&mut doc, &all_deltas);
+        apply_deltas(&mut doc, &all_deltas)?;
-        TextDocument { doc, deltas }
+        Ok(TextDocument { doc, deltas })
     }
 
-    pub fn update(&mut self, value: &str) -> bool {
+    pub fn update(&mut self, value: &str) -> Result<bool> {
         let diffs = operations::get_delta_operations(&self.to_string(), value);
         let event = deltas::Delta {
             operations: diffs,
@@ -50,11 +51,11 @@ impl TextDocument {
                 .as_millis(),
         };
         if event.operations.len() == 0 {
-            return false;
+            return Ok(false);
         }
-        apply_deltas(&mut self.doc, &vec![event.clone()]);
+        apply_deltas(&mut self.doc, &vec![event.clone()])?;
         self.deltas.push(event);
-        return true;
+        return Ok(true);
     }
 
     pub fn to_string(&self) -> String {

src-tauri/src/deltas/text_document_tests.rs

@@ -3,14 +3,18 @@ use crate::deltas::{operations::Operation, text_document::TextDocument, Delta};
 #[test]
 fn test_new() {
     let document = TextDocument::new("hello world", vec![]);
+    assert_eq!(document.is_ok(), true);
+    let document = document.unwrap();
     assert_eq!(document.to_string(), "hello world");
     assert_eq!(document.get_deltas().len(), 0);
 }
 
 #[test]
 fn test_update() {
-    let mut document = TextDocument::new("hello world", vec![]);
+    let document = TextDocument::new("hello world", vec![]);
-    document.update("hello world!");
+    assert_eq!(document.is_ok(), true);
+    let mut document = document.unwrap();
+    document.update("hello world!").unwrap();
     assert_eq!(document.to_string(), "hello world!");
     assert_eq!(document.get_deltas().len(), 1);
     assert_eq!(document.get_deltas()[0].operations.len(), 1);
@@ -22,8 +26,10 @@ fn test_update() {
 
 #[test]
 fn test_empty() {
-    let mut document = TextDocument::from_deltas(vec![]);
+    let document = TextDocument::from_deltas(vec![]);
-    document.update("hello world!");
+    assert_eq!(document.is_ok(), true);
+    let mut document = document.unwrap();
+    document.update("hello world!").unwrap();
     assert_eq!(document.to_string(), "hello world!");
     assert_eq!(document.get_deltas().len(), 1);
     assert_eq!(document.get_deltas()[0].operations.len(), 1);
@@ -52,14 +58,18 @@ fn test_from_deltas() {
             ],
         },
     ]);
+    assert_eq!(document.is_ok(), true);
+    let document = document.unwrap();
     assert_eq!(document.to_string(), "held!");
 }
 
 #[test]
 fn test_complex_line() {
-    let mut document = TextDocument::from_deltas(vec![]);
+    let document = TextDocument::from_deltas(vec![]);
+    assert_eq!(document.is_ok(), true);
+    let mut document = document.unwrap();
 
-    document.update("hello");
+    document.update("hello").unwrap();
     assert_eq!(document.to_string(), "hello");
     assert_eq!(document.get_deltas().len(), 1);
     assert_eq!(document.get_deltas()[0].operations.len(), 1);
@@ -68,7 +78,7 @@ fn test_complex_line() {
         Operation::Insert((0, "hello".to_string()))
     );
 
-    document.update("hello world");
+    document.update("hello world").unwrap();
     assert_eq!(document.to_string(), "hello world");
     assert_eq!(document.get_deltas().len(), 2);
     assert_eq!(document.get_deltas()[1].operations.len(), 1);
@@ -77,7 +87,7 @@ fn test_complex_line() {
         Operation::Insert((5, " world".to_string()))
     );
 
-    document.update("held!");
+    document.update("held!").unwrap();
     assert_eq!(document.to_string(), "held!");
     assert_eq!(document.get_deltas().len(), 3);
     assert_eq!(document.get_deltas()[2].operations.len(), 2);
@@ -93,9 +103,11 @@ fn test_complex_line() {
 
 #[test]
 fn test_multiline_add() {
-    let mut document = TextDocument::from_deltas(vec![]);
+    let document = TextDocument::from_deltas(vec![]);
+    assert_eq!(document.is_ok(), true);
+    let mut document = document.unwrap();
 
-    document.update("first");
+    document.update("first").unwrap();
     assert_eq!(document.to_string(), "first");
     assert_eq!(document.get_deltas().len(), 1);
     assert_eq!(document.get_deltas()[0].operations.len(), 1);
@@ -104,7 +116,7 @@ fn test_multiline_add() {
         Operation::Insert((0, "first".to_string()))
     );
 
-    document.update("first\ntwo");
+    document.update("first\ntwo").unwrap();
     assert_eq!(document.to_string(), "first\ntwo");
     assert_eq!(document.get_deltas().len(), 2);
     assert_eq!(document.get_deltas()[1].operations.len(), 1);
@@ -113,7 +125,7 @@ fn test_multiline_add() {
         Operation::Insert((5, "\ntwo".to_string()))
     );
 
-    document.update("first line\nline two");
+    document.update("first line\nline two").unwrap();
     assert_eq!(document.to_string(), "first line\nline two");
     assert_eq!(document.get_deltas().len(), 3);
     assert_eq!(document.get_deltas()[2].operations.len(), 2);
@@ -129,9 +141,11 @@ fn test_multiline_add() {
 
 #[test]
 fn test_multiline_remove() {
-    let mut document = TextDocument::from_deltas(vec![]);
+    let document = TextDocument::from_deltas(vec![]);
+    assert_eq!(document.is_ok(), true);
+    let mut document = document.unwrap();
 
-    document.update("first line\nline two");
+    document.update("first line\nline two").unwrap();
     assert_eq!(document.to_string(), "first line\nline two");
     assert_eq!(document.get_deltas().len(), 1);
     assert_eq!(document.get_deltas()[0].operations.len(), 1);
@@ -140,7 +154,7 @@ fn test_multiline_remove() {
         Operation::Insert((0, "first line\nline two".to_string()))
     );
 
-    document.update("first\ntwo");
+    document.update("first\ntwo").unwrap();
     assert_eq!(document.to_string(), "first\ntwo");
     assert_eq!(document.get_deltas().len(), 2);
     assert_eq!(document.get_deltas()[1].operations.len(), 2);
@@ -153,7 +167,7 @@ fn test_multiline_remove() {
         Operation::Delete((6, 5))
     );
 
-    document.update("first");
+    document.update("first").unwrap();
     assert_eq!(document.to_string(), "first");
     assert_eq!(document.get_deltas().len(), 3);
     assert_eq!(document.get_deltas()[2].operations.len(), 1);
@@ -162,7 +176,7 @@ fn test_multiline_remove() {
         Operation::Delete((5, 4))
     );
 
-    document.update("");
+    document.update("").unwrap();
     assert_eq!(document.to_string(), "");
     assert_eq!(document.get_deltas().len(), 4);
     assert_eq!(document.get_deltas()[3].operations.len(), 1);