Add apply_text_edits method to workspace document

Author: masad-frost

pylsp/workspace.py

@@ -129,6 +129,65 @@ def _create_document(self, doc_uri, source=None, version=None):
         )
 
 
+def get_well_formatted_range(range):
+    start = range['start']
+    end = range['end']
+
+    if start['line'] > end['line'] or (start['line'] == end['line'] and start['character'] > end['character']):
+        return { 'start': end, 'end': start }
+
+    return range
+
+def get_well_formatted_edit(text_edit):
+    range = get_well_formatted_range(text_edit['range'])
+    if range != text_edit['range']:
+        return { 'newText': text_edit['newText'], 'range': range }
+    
+    return text_edit
+
+def compare_text_edits(a, b):
+    diff = a['range']['start']['line'] - b['range']['start']['line']
+    if diff == 0:
+        return a['range']['start']['character'] - b['range']['start']['character']
+    
+    return diff
+
+def merge_sort_text_edits(text_edits):
+    if len(text_edits) <= 1:
+        return text_edits
+    
+    p = len(text_edits) // 2
+    left = text_edits[:p]
+    right = text_edits[p:]
+
+    merge_sort_text_edits(left)
+    merge_sort_text_edits(right)
+
+    left_idx = 0
+    right_idx = 0
+    i = 0
+    while left_idx < len(left) and right_idx < len(right):
+        ret = compare_text_edits(left[left_idx], right[right_idx])
+        if ret <= 0:
+            #  smaller_equal -> take left to preserve order
+            text_edits[i] = left[left_idx]
+            i += 1
+            left_idx += 1
+        else:
+            # greater -> take right
+            text_edits[i] = right[right_idx]
+            i+=1
+            right_idx +=1
+    while left_idx < len(left):
+        text_edits[i] = left[left_idx]
+        i += 1
+        left_idx += 1
+    while right_idx < len(right):
+        text_edits[i] = right[right_idx]
+        i += 1
+        right_idx += 1
+    return text_edits
+
 class Document:
 
     def __init__(self, uri, workspace, source=None, version=None, local=True, extra_sys_path=None,
@@ -216,6 +275,26 @@ def apply_change(self, change):
 
         self._source = new.getvalue()
 
+    @lock
+    def apply_text_edits(self, text_edits):
+        text = self._source
+        sorted_edits = merge_sort_text_edits(list(map(get_well_formatted_edit,text_edits)))
+        last_modified_offset = 0
+        spans = []
+        for e in sorted_edits:
+            start_offset = self.offset_at_position(e['range']['start'])
+            if start_offset < last_modified_offset:
+                raise Exception('overlapping edit')
+            elif start_offset > last_modified_offset:
+                spans.append(text[last_modified_offset:start_offset])
+            
+            if len(e['newText']):
+                spans.append(e['newText'])
+            last_modified_offset = self.offset_at_position(e['range']['end'])
+
+        spans.append(text[last_modified_offset:])
+        return ''.join(spans)
+
     def offset_at_position(self, position):
         """Return the byte-offset pointed at by the given position."""
         return position['character'] + len(''.join(self.lines[:position['line']]))