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Manual yield doesn't block new shares

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This commit is contained in:
Matthew Draper 2016-02-08 05:22:56 +10:30
parent fe7d77cc01
commit 11579b8306
1 changed files with 6 additions and 5 deletions
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11
activesupport/lib/active_support/concurrency/share_lock.rb
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@ -45,7 +45,7 @@ module ActiveSupport
if busy_for_exclusive?(purpose) if busy_for_exclusive?(purpose)
return false if no_wait return false if no_wait
yield_shares(purpose: purpose, compatible: compatible) do yield_shares(purpose: purpose, compatible: compatible, block_share: true) do
@cv.wait_while { busy_for_exclusive?(purpose) } @cv.wait_while { busy_for_exclusive?(purpose) }
end end
end end
@ -68,7 +68,7 @@ module ActiveSupport
@exclusive_thread = nil @exclusive_thread = nil
if eligible_waiters?(compatible) if eligible_waiters?(compatible)
yield_shares(compatible: compatible) do yield_shares(compatible: compatible, block_share: true) do
@cv.wait_while { @exclusive_thread || eligible_waiters?(compatible) } @cv.wait_while { @exclusive_thread || eligible_waiters?(compatible) }
end end
end end
@ -77,7 +77,7 @@ module ActiveSupport
end end
end end
def start_sharing(purpose: :share) def start_sharing
synchronize do synchronize do
if @sharing[Thread.current] > 0 || @exclusive_thread == Thread.current if @sharing[Thread.current] > 0 || @exclusive_thread == Thread.current
# We already hold a lock; nothing to wait for # We already hold a lock; nothing to wait for
@ -88,7 +88,7 @@ module ActiveSupport
else else
# This is an initial / outermost share call: any outstanding # This is an initial / outermost share call: any outstanding
# requests for an exclusive lock get to go first # requests for an exclusive lock get to go first
@cv.wait_while { busy_for_sharing?(purpose) } @cv.wait_while { busy_for_sharing?(false) }
end end
@sharing[Thread.current] += 1 @sharing[Thread.current] += 1
end end
@ -134,7 +134,7 @@ module ActiveSupport
# Temporarily give up all held Share locks while executing the # Temporarily give up all held Share locks while executing the
# supplied block, allowing any +compatible+ exclusive lock request # supplied block, allowing any +compatible+ exclusive lock request
# to proceed. # to proceed.
def yield_shares(purpose: nil, compatible: []) def yield_shares(purpose: nil, compatible: [], block_share: false)
loose_shares = previous_wait = nil loose_shares = previous_wait = nil
synchronize do synchronize do
if loose_shares = @sharing.delete(Thread.current) if loose_shares = @sharing.delete(Thread.current)
@ -142,6 +142,7 @@ module ActiveSupport
purpose = nil unless purpose == previous_wait[0] purpose = nil unless purpose == previous_wait[0]
compatible &= previous_wait[1] compatible &= previous_wait[1]
end end
compatible |= [false] unless block_share
@waiting[Thread.current] = [purpose, compatible] @waiting[Thread.current] = [purpose, compatible]
@cv.broadcast @cv.broadcast