A more complex cache for hide_non_rst_blocks()

Author: AlexWaygood

sphinxlint/utils.py

@@ -142,12 +142,22 @@ def is_multiline_non_rst_block(line):
     return False
 
 
+_NON_RST_BLOCKS_CACHE = {}
+
+
 def hide_non_rst_blocks(lines, hidden_block_cb=None):
     """Filters out literal, comments, code blocks, ...
 
     The filter actually replace "removed" lines by empty lines, so the
     line numbering still make sense.
+
+    This function is quite hot, so we cache the returned value where possible.
+    The function is only "pure" when hidden_block_cb is None, however,
+    so we can only safely cache the output when hidden_block_cb=None.
     """
+    lines = tuple(lines)
+    if hidden_block_cb is None and lines in _NON_RST_BLOCKS_CACHE:
+        return _NON_RST_BLOCKS_CACHE[lines]
     in_literal = None
     excluded_lines = []
     block_line_start = None
@@ -175,6 +185,9 @@ def hide_non_rst_blocks(lines, hidden_block_cb=None):
         output.append(line)
     if excluded_lines and hidden_block_cb:
         hidden_block_cb(block_line_start, "".join(excluded_lines))
+    output = tuple(output)
+    if hidden_block_cb is None:
+        _NON_RST_BLOCKS_CACHE[lines] = output
     return output