diff options
| author | schneems <[email protected]> | 2023-04-14 13:46:28 -0500 |
|---|---|---|
| committer | Hiroshi SHIBATA <[email protected]> | 2023-05-23 10:05:47 +0900 |
| commit | aaf815c626816ccca227cb1f8f2a9b58f18f677a (patch) | |
| tree | df1851edb5ed016a1b41124b851b3bf7a6daef40 /lib/syntax_suggest/scan_history.rb | |
| parent | b8bf0a52723322e469e94a4cb96286fd48e754ab (diff) | |
[ruby/syntax_suggest] Refactor Scanner logic out of AroundBlockScan introduce history
AroundBlockScan started as a utility class that was meant to be used as a DSL for scanning and making new blocks. As logic got added to this class it became hard to reason about what exactly is being mutated when. I pulled the scanning logic out into it's own class which gives us a clean separation of concerns. This allowed me to remove a lot of accessors that aren't core to the logic provided by AroundBlockScan.
In addition to this refactor the ScanHistory class can snapshot a scan. This allows us to be more aggressive with scans in the future as we can now snapshot and rollback if it didn't turn out the way we wanted.
The change comes with a minor perf impact:
before: 5.092678 0.104299 5.196977 ( 5.226494)
after: 5.128536 0.099871 5.228407 ( 5.249542)
This represents a 0.996x change in speed (where 1x would be no change and 2x would be twice as fast). This is a 0.38% decrease in performance which is negligible. It's likely coming from the extra blocks being created while scanning. This is negligible and if the history feature works well we might be able to make better block decisions which is means fewer calls to ripper which is the biggest bottleneck.
While this doesn't fix https://github.com/ruby/syntax_suggest/issues/187 it's a good intermediate step that will hopefully make working on that issue easier.
https://github.com/ruby/syntax_suggest/commit/ad8487d8aa
Diffstat (limited to 'lib/syntax_suggest/scan_history.rb')
| -rw-r--r-- | lib/syntax_suggest/scan_history.rb | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/lib/syntax_suggest/scan_history.rb b/lib/syntax_suggest/scan_history.rb new file mode 100644 index 0000000000..c5664d0f65 --- /dev/null +++ b/lib/syntax_suggest/scan_history.rb @@ -0,0 +1,113 @@ +# frozen_string_literal: true + +module SyntaxSuggest + # Scans up/down from the given block + # + # You can snapshot a change by committing it and rolling back. + # + class ScanHistory + attr_reader :before_index, :after_index + + def initialize(code_lines:, block:) + @code_lines = code_lines + @history = [block] + refresh_index + end + + def commit_if_changed + if changed? + @history << CodeBlock.new(lines: @code_lines[before_index..after_index]) + refresh_index + end + + self + end + + def try_rollback + if @history.length > 1 + @history.pop + refresh_index + end + + self + end + + def changed? + @before_index != current.lines.first.index || + @after_index != current.lines.last.index + end + + # Iterates up and down + # + # Returns line, kw_count, end_count for each iteration + def scan(up:, down:) + kw_count = 0 + end_count = 0 + + up_index = before_lines.reverse_each.take_while do |line| + kw_count += 1 if line.is_kw? + end_count += 1 if line.is_end? + up.call(line, kw_count, end_count) + end.last&.index + + kw_count = 0 + end_count = 0 + + down_index = after_lines.each.take_while do |line| + kw_count += 1 if line.is_kw? + end_count += 1 if line.is_end? + down.call(line, kw_count, end_count) + end.last&.index + + @before_index = if up_index && up_index < @before_index + up_index + else + @before_index + end + + @after_index = if down_index && down_index > @after_index + down_index + else + @after_index + end + + self + end + + def next_up + return nil if @before_index <= 0 + + @code_lines[@before_index - 1] + end + + def next_down + return nil if @after_index >= @code_lines.length + + @code_lines[@after_index + 1] + end + + def lines + @code_lines[@before_index..@after_index] + end + + private def before_lines + @code_lines[0...@before_index] || [] + end + + # Returns an array of all the CodeLines that exist after + # the currently scanned block + private def after_lines + @code_lines[@after_index.next..-1] || [] + end + + private def current + @history.last + end + + private def refresh_index + @before_index = current.lines.first.index + @after_index = current.lines.last.index + self + end + end +end |