Module sentinel 

Shared sentinel-block primitives used by shells::profile and sys::profile to find, extract, remove, and insert the # >>> ... >>> / # <<< ... <<< blocks shine writes into user-owned shell profile files.

Two removal styles are kept deliberately separate (remove_block_bytewise vs remove_block_linewise): they differ in preceding-blank-line handling and CRLF behavior (see each function’s docs), and canonicalizing them without golden-output proof that neither caller depends on the difference would risk a silent formatting regression in a file shine does not own. Do not merge them without characterization tests confirming both callers’ current byte-for-byte output is preserved.

Structs

Sentinel

A sentinel marker pair, e.g. ("# >>> shine >>>", "# <<< shine <<<").

Enums

InsertAt

Where to insert a block relative to existing content, for insert_block.

Functions

extract_block_with_newline

Like find_block, but also includes one trailing '\n' immediately after the end marker if present. The end marker is searched for only after the start marker, so an end marker that appears before the start marker is not matched.

find_block

Returns the substring from the start marker through the end marker (inclusive), or None if either marker is missing. Does not include any trailing newline after the end marker.

insert_block

Inserts block into content, separated from any existing content by exactly one blank line (regardless of whether block or content already end/start with a newline). When content is empty, no leading/trailing blank line is added — the result is just block.

remove_block_bytewise

Byte-offset block removal (shells::profile’s semantics).

remove_block_linewise

Line-based block removal (sys::profile’s semantics).

trim_outer_blank_lines

Trims all leading and trailing '\n' characters (not just one).