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96 lines
3.2 KiB
96 lines
3.2 KiB
package resource_pool
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import (
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"time"
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)
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type Options struct {
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// The maximum number of active resource handles per resource location. (A
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// non-positive value indicates the number of active resource handles is
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// unbounded).
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MaxActiveHandles int32
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// The maximum number of idle resource handles per resource location that
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// are kept alive by the resource pool.
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MaxIdleHandles uint32
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// The maximum amount of time an idle resource handle can remain alive (if
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// specified).
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MaxIdleTime *time.Duration
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// This limits the number of concurrent Open calls (there's no limit when
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// OpenMaxConcurrency is non-positive).
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OpenMaxConcurrency int
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// This function creates a resource handle (e.g., a connection) for a
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// resource location. The function must be thread-safe.
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Open func(resourceLocation string) (
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handle interface{},
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err error)
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// This function destroys a resource handle and performs the necessary
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// cleanup to free up resources. The function must be thread-safe.
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Close func(handle interface{}) error
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// This specifies the now time function. When the function is non-nil, the
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// resource pool will use the specified function instead of time.Now to
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// generate the current time.
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NowFunc func() time.Time
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}
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func (o Options) getCurrentTime() time.Time {
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if o.NowFunc == nil {
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return time.Now()
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} else {
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return o.NowFunc()
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}
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}
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// A generic interface for managed resource pool. All resource pool
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// implementations must be threadsafe.
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type ResourcePool interface {
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// This returns the number of active resource handles.
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NumActive() int32
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// This returns the highest number of actives handles for the entire
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// lifetime of the pool. If the pool contains multiple sub-pools, the
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// high water mark is the max of the sub-pools' high water marks.
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ActiveHighWaterMark() int32
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// This returns the number of alive idle handles. NOTE: This is only used
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// for testing.
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NumIdle() int
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// This associates a resource location to the resource pool; afterwhich,
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// the user can get resource handles for the resource location.
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Register(resourceLocation string) error
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// This dissociates a resource location from the resource pool; afterwhich,
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// the user can no longer get resource handles for the resource location.
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// If the given resource location corresponds to a sub-pool, the unregistered
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// sub-pool will enter lame duck mode.
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Unregister(resourceLocation string) error
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// This returns the list of registered resource location entries.
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ListRegistered() []string
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// This gets an active resource handle from the resource pool. The
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// handle will remain active until one of the following is called:
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// 1. handle.Release()
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// 2. handle.Discard()
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// 3. pool.Release(handle)
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// 4. pool.Discard(handle)
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Get(key string) (ManagedHandle, error)
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// This releases an active resource handle back to the resource pool.
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Release(handle ManagedHandle) error
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// This discards an active resource from the resource pool.
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Discard(handle ManagedHandle) error
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// Enter the resource pool into lame duck mode. The resource pool
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// will no longer return resource handles, and all idle resource handles
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// are closed immediately (including active resource handles that are
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// released back to the pool afterward).
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EnterLameDuckMode()
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}
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