Improving test coverage for btree::cursor

Dependencies

• [2] ONES3V46 reference counting works for put
• [3] OP6SVMOD Resetting history
• [4] FMN7X4J2 Micro-improvements, now noticeably faster than std::collections::BTreeMap
• [5] WS4ZQM4R Debugging, tests, etc.

Change contents

• edit in sanakirja-core/src/btree/cursor.rs at line 86
  [3.2548]→[2.1544:1601](∅→∅)
  − debug!("self.pointer = {:?}", self.pointer);
• edit in sanakirja-core/src/btree/cursor.rs at line 88
  [3.66371]→[2.1602:1684](∅→∅)
  − debug!("page = {:?}, rc = {:?}", current.page, txn.rc(page.offset)?);
• edit in sanakirja-core/src/btree/cursor.rs at line 89
  [3.66450]→[2.1685:1748](∅→∅)
  − debug!("first_rc_level = {:?}", self.pointer);
• edit in sanakirja-core/src/btree/cursor.rs at line 105
  [3.34397]→[3.34397:34448](∅→∅)
  − debug!("next_page = {:?}", next_page);
• edit in sanakirja-core/src/btree/cursor.rs at line 107
  [3.67229]→[3.34449:34500](∅→∅)
  − debug!("p+ = {:?}", self.pointer);
• edit in sanakirja-core/src/btree/cursor.rs at line 112
  [3.67430]→[3.34681:34736](∅→∅)
  − debug!("last p = {:?}", self.pointer);
• edit in sanakirja-core/src/btree/cursor.rs at line 116
  [3.67513]→[3.34737:34799](∅→∅)
  − debug!("last_matching {:?}", last_matching_page);
• edit in sanakirja-core/src/btree/cursor.rs at line 119
  [3.67604]→[3.34800:34850](∅→∅)
  − debug!("pointer {:?}", self.pointer);
• replacement in sanakirja-core/src/btree/cursor.rs at line 156
  [3.68948]→[3.68948:69343](∅→∅),[3.69343]→[3.35301:35383](∅→∅),[3.35383]→[3.69416:69743](∅→∅),[3.69416]→[3.69416:69743](∅→∅),[3.69743]→[3.35384:35439](∅→∅),[3.35439]→[3.69804:70012](∅→∅),[3.69804]→[3.69804:70012](∅→∅),[3.70012]→[3.35440:35524](∅→∅),[3.35524]→[3.70087:70218](∅→∅),[3.70087]→[3.70087:70218](∅→∅),[3.70218]→[3.35525:35603](∅→∅),[3.35603]→[3.70287:70442](∅→∅),[3.70287]→[3.70287:70442](∅→∅)
  − if self.pointer == 0 {

  − return Ok(None);

  − } else {

  − let current = unsafe { &mut *self.stack[self.pointer].as_mut_ptr() };

  − if let Some(ref mut c) = current.cursor {

  − // We're inside the page, and have already

  − // processed the left child of the current page

  − // cursor.

  − if let Some((k, v, r)) = P::next(current.page.as_page(), c) {

  − if r > 0 {

  − self.pointer += 1;

  − self.stack[self.pointer] = MaybeUninit::new(PageCursor {

  − page: txn.load_page(r)?,

  − cursor: None,

  − })

  − }

  − return Ok(Some((& *k, & *v)));

  − } else if self.pointer > 1 {

  − self.pointer -= 1

  − } else {

  − return Ok(None);

  − }

  − } else {

  − current.cursor = Some(P::first_cursor(current.page.as_page()));

  − // First element of a page (not a binding).

  − let cursor = current.cursor.as_ref().unwrap();

  − let left = P::left_child(current.page.as_page(), cursor);

  − debug!("left = {:?}", left);

  − // Then visit the right child (if any), i.e. push.

  − if left != 0 {
  [3.68948]

  [3.70442]
  + let current = unsafe { &mut *self.stack[self.pointer].as_mut_ptr() };

  + if let Some(ref mut c) = current.cursor {

  + // We're inside the page, and have already

  + // processed the left child of the current page

  + // cursor.

  + if let Some((k, v, r)) = P::next(current.page.as_page(), c) {

  + if r > 0 {
• replacement in sanakirja-core/src/btree/cursor.rs at line 165
  [3.70566]→[3.70566:70622](∅→∅)
  − page: txn.load_page(left)?,
  [3.70566]

  [3.70622]
  + page: txn.load_page(r)?,
• edit in sanakirja-core/src/btree/cursor.rs at line 169
  [3.70713]

  [3.70713]
  + return Ok(Some((& *k, & *v)));

  + } else if self.pointer > 1 {

  + self.pointer -= 1

  + } else {

  + return Ok(None);

  + }

  + } else {

  + current.cursor = Some(P::first_cursor(current.page.as_page()));

  + // First element of a page (not a binding).

  + let cursor = current.cursor.as_ref().unwrap();

  + let left = P::left_child(current.page.as_page(), cursor);

  + // Then visit the right child (if any), i.e. push.

  + if left != 0 {

  + self.pointer += 1;

  + self.stack[self.pointer] = MaybeUninit::new(PageCursor {

  + page: txn.load_page(left)?,

  + cursor: None,

  + })
• replacement in sanakirja/src/environment/muttxn.rs at line 17
  [3.80384]→[3.37289:37308](∅→∅)
  − free: CowPage,
  [3.80384]

  [3.80400]
  + pub(crate) free: CowPage,