diff options
Diffstat (limited to 'activesupport/lib/active_support/concurrency')
-rw-r--r-- | activesupport/lib/active_support/concurrency/share_lock.rb | 56 |
1 files changed, 37 insertions, 19 deletions
diff --git a/activesupport/lib/active_support/concurrency/share_lock.rb b/activesupport/lib/active_support/concurrency/share_lock.rb index ca48164c54..8e4ca272ba 100644 --- a/activesupport/lib/active_support/concurrency/share_lock.rb +++ b/activesupport/lib/active_support/concurrency/share_lock.rb @@ -48,17 +48,11 @@ module ActiveSupport def start_exclusive(purpose: nil, compatible: [], no_wait: false) synchronize do unless @exclusive_thread == Thread.current - if busy?(purpose) + if busy_for_exclusive?(purpose) return false if no_wait - loose_shares = @sharing.delete(Thread.current) - @waiting[Thread.current] = compatible if loose_shares - - begin - @cv.wait_while { busy?(purpose) } - ensure - @waiting.delete Thread.current - @sharing[Thread.current] = loose_shares if loose_shares + yield_shares(purpose, compatible) do + @cv.wait_while { busy_for_exclusive?(purpose) } end end @exclusive_thread = Thread.current @@ -71,22 +65,26 @@ module ActiveSupport # Relinquish the exclusive lock. Must only be called by the thread # that called start_exclusive (and currently holds the lock). - def stop_exclusive + def stop_exclusive(compatible: []) synchronize do raise "invalid unlock" if @exclusive_thread != Thread.current @exclusive_depth -= 1 if @exclusive_depth == 0 @exclusive_thread = nil - @cv.broadcast + + yield_shares(nil, compatible) do + @cv.broadcast + @cv.wait_while { @exclusive_thread || eligible_waiters?(compatible) } + end end end end - def start_sharing + def start_sharing(purpose: :share) synchronize do - if @exclusive_thread && @exclusive_thread != Thread.current - @cv.wait_while { @exclusive_thread } + if @sharing[Thread.current] == 0 && @exclusive_thread != Thread.current && busy_for_sharing?(purpose) + @cv.wait_while { busy_for_sharing?(purpose) } end @sharing[Thread.current] += 1 end @@ -109,12 +107,12 @@ module ActiveSupport # the block. # # See +start_exclusive+ for other options. - def exclusive(purpose: nil, compatible: [], no_wait: false) + def exclusive(purpose: nil, compatible: [], after_compatible: [], no_wait: false) if start_exclusive(purpose: purpose, compatible: compatible, no_wait: no_wait) begin yield ensure - stop_exclusive + stop_exclusive(compatible: after_compatible) end end end @@ -132,11 +130,31 @@ module ActiveSupport private # Must be called within synchronize - def busy?(purpose) - (@exclusive_thread && @exclusive_thread != Thread.current) || - @waiting.any? { |k, v| k != Thread.current && !v.include?(purpose) } || + def busy_for_exclusive?(purpose) + busy_for_sharing?(purpose) || @sharing.size > (@sharing[Thread.current] > 0 ? 1 : 0) end + + def busy_for_sharing?(purpose) + (@exclusive_thread && @exclusive_thread != Thread.current) || + @waiting.any? { |t, (_, c)| t != Thread.current && !c.include?(purpose) } + end + + def eligible_waiters?(compatible) + @waiting.any? { |t, (p, _)| compatible.include?(p) && @waiting.all? { |t2, (_, c2)| t == t2 || c2.include?(p) } } + end + + def yield_shares(purpose, compatible) + loose_shares = @sharing.delete(Thread.current) + @waiting[Thread.current] = [purpose, compatible] if loose_shares + + begin + yield + ensure + @waiting.delete Thread.current + @sharing[Thread.current] = loose_shares if loose_shares + end + end end end end |