Merge pull request #456 from fractaledmind/fix-busy_handler_timeout-t…

…ests

busy_handler_timeout pt2

lib/sqlite3/database.rb

@@ -695,6 +695,25 @@ def readonly?
       @readonly
     end
 
+    # Sets a #busy_handler that releases the GVL between retries,
+    # but only retries up to the indicated number of +milliseconds+.
+    # This is an alternative to #busy_timeout, which holds the GVL
+    # while SQLite sleeps and retries.
+    def busy_handler_timeout=( milliseconds )
+      timeout_seconds = milliseconds.fdiv(1000)
+
+      busy_handler do |count|
+        now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        if count.zero?
+          @timeout_deadline = now + timeout_seconds
+        elsif now > @timeout_deadline
+          next false
+        else
+          sleep(0.001)
+        end
+      end
+    end
+
     # A helper class for dealing with custom functions (see #create_function,
     # #create_aggregate, and #create_aggregate_handler). It encapsulates the
     # opaque function object that represents the current invocation. It also

test/test_integration_pending.rb

@@ -74,4 +74,42 @@ def test_busy_timeout
 
     assert_operator time.real * 1000, :>=, 1000
   end
+
+  def test_busy_handler_timeout_releases_gvl
+    work = []
+
+    Thread.new do
+      while true
+        sleep 0.1
+        work << '.'
+      end
+    end
+    sleep 1
+
+    @db.busy_handler_timeout = 1000
+    busy = Mutex.new
+    busy.lock
+
+    t = Thread.new do
+      begin
+        db2 = SQLite3::Database.open( "test.db" )
+        db2.transaction( :exclusive ) do
+          busy.lock
+        end
+      ensure
+        db2.close if db2
+      end
+    end
+    sleep 1
+
+    assert_raises( SQLite3::BusyException ) do
+      work << '|'
+      @db.execute "insert into foo (b) values ( 'from 2' )"
+    end
+
+    busy.unlock
+    t.join
+
+    assert work.size - work.find_index('|') > 3
+  end
 end