add new extention traits for Range and DocumentChange (#287)

crates/djls-server/src/ext.rs

@@ -5,18 +5,25 @@ use djls_source::LineCol;
 use djls_source::LineIndex;
 use djls_source::Offset;
 use djls_source::PositionEncoding;
+use djls_source::Range;
 use djls_workspace::Db as WorkspaceDb;
+use djls_workspace::DocumentChange;
 use tower_lsp_server::lsp_types;
 use tower_lsp_server::UriExt as TowerUriExt;
 
 pub(crate) trait PositionExt {
-    fn to_offset(&self, text: &str, index: &LineIndex, encoding: PositionEncoding) -> Offset;
+    fn to_line_col(&self) -> LineCol;
+    fn to_offset(&self, text: &str, line_index: &LineIndex, encoding: PositionEncoding) -> Offset;
 }
 
 impl PositionExt for lsp_types::Position {
-    fn to_offset(&self, text: &str, index: &LineIndex, encoding: PositionEncoding) -> Offset {
-        let line_col = LineCol::new(self.line, self.character);
-        index.offset(line_col, text, encoding)
+    fn to_line_col(&self) -> LineCol {
+        LineCol::new(self.line, self.character)
+    }
+
+    fn to_offset(&self, text: &str, line_index: &LineIndex, encoding: PositionEncoding) -> Offset {
+        let line_col = self.to_line_col();
+        line_index.offset(text, line_col, encoding)
     }
 }
 
@@ -49,6 +56,32 @@ impl PositionEncodingKindExt for lsp_types::PositionEncodingKind {
     }
 }
 
+pub(crate) trait RangeExt {
+    fn to_source_range(&self) -> Range;
+}
+
+impl RangeExt for lsp_types::Range {
+    fn to_source_range(&self) -> Range {
+        let start_line_col = self.start.to_line_col();
+        let end_line_col = self.end.to_line_col();
+        Range::new(start_line_col, end_line_col)
+    }
+}
+
+pub(crate) trait TextDocumentContentChangeEventExt {
+    fn to_document_changes(self) -> Vec<DocumentChange>;
+}
+
+impl TextDocumentContentChangeEventExt for Vec<lsp_types::TextDocumentContentChangeEvent> {
+    fn to_document_changes(self) -> Vec<DocumentChange> {
+        self.into_iter()
+            .map(|change| {
+                DocumentChange::new(change.range.map(|r| r.to_source_range()), change.text)
+            })
+            .collect()
+    }
+}
+
 pub(crate) trait TextDocumentIdentifierExt {
     fn to_file(&self, db: &mut dyn WorkspaceDb) -> Option<File>;
 }

crates/djls-server/src/session.rs

@@ -16,6 +16,7 @@ use tower_lsp_server::lsp_types;
 
 use crate::db::DjangoDatabase;
 use crate::ext::PositionEncodingKindExt;
+use crate::ext::TextDocumentContentChangeEventExt;
 use crate::ext::UriExt;
 
 /// LSP Session managing project-specific state and database operations.
@@ -155,21 +156,10 @@ impl Session {
             return None;
         };
 
-        let doc_changes = changes
-            .into_iter()
-            .map(|change| djls_workspace::DocumentChange {
-                range: change.range.map(|r| djls_source::Range {
-                    start: djls_source::LineCol::new(r.start.line, r.start.character),
-                    end: djls_source::LineCol::new(r.end.line, r.end.character),
-                }),
-                text: change.text,
-            })
-            .collect();
-
         let document = self.workspace.update_document(
             &mut self.db,
             &path,
-            doc_changes,
+            changes.to_document_changes(),
             text_document.version,
             self.client_capabilities.position_encoding(),
         )?;

crates/djls-source/src/line.rs

@@ -88,7 +88,7 @@ impl LineIndex {
     }
 
     #[must_use]
-    pub fn offset(&self, line_col: LineCol, text: &str, encoding: PositionEncoding) -> Offset {
+    pub fn offset(&self, text: &str, line_col: LineCol, encoding: PositionEncoding) -> Offset {
         let line = line_col.line();
         let character = line_col.column();
 

crates/djls-source/src/position.rs

@@ -107,8 +107,25 @@ impl From<&LineCol> for (u32, u32) {
 }
 
 pub struct Range {
-    pub start: LineCol,
-    pub end: LineCol,
+    start: LineCol,
+    end: LineCol,
+}
+
+impl Range {
+    #[must_use]
+    pub fn new(start: LineCol, end: LineCol) -> Self {
+        Self { start, end }
+    }
+
+    #[must_use]
+    pub fn start(&self) -> LineCol {
+        self.start
+    }
+
+    #[must_use]
+    pub fn end(&self) -> LineCol {
+        self.end
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize)]

crates/djls-workspace/src/document.rs

@@ -89,16 +89,7 @@ impl TextDocument {
         let mut line_index = self.line_index.clone();
 
         for change in changes {
-            if let Some(range) = change.range {
-                let start_offset =
-                    line_index.offset(range.start, &content, encoding).get() as usize;
-                let end_offset = line_index.offset(range.end, &content, encoding).get() as usize;
-
-                content.replace_range(start_offset..end_offset, &change.text);
-            } else {
-                content = change.text;
-            }
-
+            content = change.apply(&content, &line_index, encoding);
             line_index = LineIndex::from(content.as_str());
         }
 
@@ -109,8 +100,47 @@ impl TextDocument {
 }
 
 pub struct DocumentChange {
-    pub range: Option<Range>,
-    pub text: String,
+    range: Option<Range>,
+    text: String,
+}
+
+impl DocumentChange {
+    #[must_use]
+    pub fn new(range: Option<Range>, text: String) -> Self {
+        Self { range, text }
+    }
+
+    #[must_use]
+    pub fn range(&self) -> &Option<Range> {
+        &self.range
+    }
+
+    #[must_use]
+    pub fn text(&self) -> &str {
+        &self.text
+    }
+
+    /// Apply this change to content, returning the new content
+    #[must_use]
+    pub fn apply(
+        &self,
+        content: &str,
+        line_index: &LineIndex,
+        encoding: PositionEncoding,
+    ) -> String {
+        if let Some(range) = &self.range {
+            let start_offset = line_index.offset(content, range.start(), encoding).get() as usize;
+            let end_offset = line_index.offset(content, range.end(), encoding).get() as usize;
+
+            let mut result = String::with_capacity(content.len() + self.text.len());
+            result.push_str(&content[..start_offset]);
+            result.push_str(&self.text);
+            result.push_str(&content[end_offset..]);
+            result
+        } else {
+            self.text.clone()
+        }
+    }
 }
 
 #[cfg(test)]
@@ -165,13 +195,10 @@ mod tests {
     fn test_incremental_update_single_change() {
         let mut doc = text_document("Hello world", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: Some(Range {
-                start: LineCol::new(0, 6),
-                end: LineCol::new(0, 11),
-            }),
-            text: "Rust".to_string(),
-        }];
+        let changes = vec![DocumentChange::new(
+            Some(Range::new(LineCol::new(0, 6), LineCol::new(0, 11))),
+            "Rust".to_string(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Hello Rust");
@@ -183,20 +210,14 @@ mod tests {
         let mut doc = text_document("First line\nSecond line\nThird line", 1, LanguageId::Other);
 
         let changes = vec![
-            DocumentChange {
-                range: Some(Range {
-                    start: LineCol::new(0, 0),
-                    end: LineCol::new(0, 5),
-                }),
-                text: "1st".to_string(),
-            },
-            DocumentChange {
-                range: Some(Range {
-                    start: LineCol::new(2, 0),
-                    end: LineCol::new(2, 5),
-                }),
-                text: "3rd".to_string(),
-            },
+            DocumentChange::new(
+                Some(Range::new(LineCol::new(0, 0), LineCol::new(0, 5))),
+                "1st".to_string(),
+            ),
+            DocumentChange::new(
+                Some(Range::new(LineCol::new(2, 0), LineCol::new(2, 5))),
+                "3rd".to_string(),
+            ),
         ];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
@@ -207,13 +228,10 @@ mod tests {
     fn test_incremental_update_insertion() {
         let mut doc = text_document("Hello world", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: Some(Range {
-                start: LineCol::new(0, 5),
-                end: LineCol::new(0, 5),
-            }),
-            text: " beautiful".to_string(),
-        }];
+        let changes = vec![DocumentChange::new(
+            Some(Range::new(LineCol::new(0, 5), LineCol::new(0, 5))),
+            " beautiful".to_string(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Hello beautiful world");
@@ -223,13 +241,10 @@ mod tests {
     fn test_incremental_update_deletion() {
         let mut doc = text_document("Hello beautiful world", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: Some(Range {
-                start: LineCol::new(0, 6),
-                end: LineCol::new(0, 16),
-            }),
-            text: String::new(),
-        }];
+        let changes = vec![DocumentChange::new(
+            Some(Range::new(LineCol::new(0, 6), LineCol::new(0, 16))),
+            String::new(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Hello world");
@@ -239,10 +254,10 @@ mod tests {
     fn test_full_document_replacement() {
         let mut doc = text_document("Old content", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: None,
-            text: "Completely new content".to_string(),
-        }];
+        let changes = vec![DocumentChange::new(
+            None,
+            "Completely new content".to_string(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Completely new content");
@@ -253,13 +268,10 @@ mod tests {
     fn test_incremental_update_multiline() {
         let mut doc = text_document("Line 1\nLine 2\nLine 3", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: Some(Range {
-                start: LineCol::new(0, 5),
-                end: LineCol::new(2, 4),
-            }),
-            text: "A\nB\nC".to_string(),
-        }];
+        let changes = vec![DocumentChange::new(
+            Some(Range::new(LineCol::new(0, 5), LineCol::new(2, 4))),
+            "A\nB\nC".to_string(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Line A\nB\nC 3");
@@ -269,13 +281,10 @@ mod tests {
     fn test_incremental_update_with_emoji() {
         let mut doc = text_document("Hello 🌍 world", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: Some(Range {
-                start: LineCol::new(0, 9),
-                end: LineCol::new(0, 14),
-            }),
-            text: "Rust".to_string(),
-        }];
+        let changes = vec![DocumentChange::new(
+            Some(Range::new(LineCol::new(0, 9), LineCol::new(0, 14))),
+            "Rust".to_string(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Hello 🌍 Rust");
@@ -285,13 +294,10 @@ mod tests {
     fn test_incremental_update_newline_at_end() {
         let mut doc = text_document("Hello", 1, LanguageId::Other);
 
-        let changes = vec![DocumentChange {
-            range: Some(Range {
-                start: LineCol::new(0, 5),
-                end: LineCol::new(0, 5),
-            }),
-            text: "\nWorld".to_string(),
-        }];
+        let changes = vec![DocumentChange::new(
+            Some(Range::new(LineCol::new(0, 5), LineCol::new(0, 5))),
+            "\nWorld".to_string(),
+        )];
 
         doc.update(changes, 2, PositionEncoding::Utf16);
         assert_eq!(doc.content(), "Hello\nWorld");

crates/djls-workspace/src/workspace.rs

@@ -101,10 +101,14 @@ impl Workspace {
             self.buffers.update(path.to_path_buf(), document.clone());
             Some(document)
         } else if let Some(first_change) = changes.into_iter().next() {
-            if first_change.range.is_none() {
+            if first_change.range().is_none() {
                 let file = db.get_or_create_file(path);
-                let document =
-                    TextDocument::new(first_change.text, version, LanguageId::Other, file);
+                let document = TextDocument::new(
+                    first_change.text().to_string(),
+                    version,
+                    LanguageId::Other,
+                    file,
+                );
                 self.buffers.open(path.to_path_buf(), document.clone());
                 Some(document)
             } else {
@@ -412,10 +416,10 @@ mod tests {
             let path = Utf8Path::new("/test.py");
             workspace.open_document(&mut db, path, "initial", 1, "python");
 
-            let changes = vec![crate::document::DocumentChange {
-                range: None,
-                text: "updated".to_string(),
-            }];
+            let changes = vec![crate::document::DocumentChange::new(
+                None,
+                "updated".to_string(),
+            )];
             let document = workspace
                 .update_document(&mut db, path, changes, 2, PositionEncoding::Utf16)
                 .unwrap();
@@ -496,10 +500,10 @@ mod tests {
                 .open_document(&mut db, &file_path, "initial", 1, "python")
                 .unwrap();
 
-            let changes = vec![crate::document::DocumentChange {
-                range: None,
-                text: "updated".to_string(),
-            }];
+            let changes = vec![crate::document::DocumentChange::new(
+                None,
+                "updated".to_string(),
+            )];
             workspace
                 .update_document(&mut db, &file_path, changes, 2, PositionEncoding::Utf16)
                 .unwrap();