62 lines
1.4 KiB
Go
62 lines
1.4 KiB
Go
package graphdriver // import "github.com/docker/docker/daemon/graphdriver"
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import "sync"
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type minfo struct {
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check bool
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count int
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}
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// RefCounter is a generic counter for use by graphdriver Get/Put calls
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type RefCounter struct {
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counts map[string]*minfo
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mu sync.Mutex
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checker Checker
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}
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// NewRefCounter returns a new RefCounter
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func NewRefCounter(c Checker) *RefCounter {
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return &RefCounter{
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checker: c,
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counts: make(map[string]*minfo),
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}
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}
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// Increment increases the ref count for the given id and returns the current count
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func (c *RefCounter) Increment(path string) int {
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return c.incdec(path, func(minfo *minfo) {
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minfo.count++
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})
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}
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// Decrement decreases the ref count for the given id and returns the current count
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func (c *RefCounter) Decrement(path string) int {
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return c.incdec(path, func(minfo *minfo) {
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minfo.count--
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})
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}
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func (c *RefCounter) incdec(path string, infoOp func(minfo *minfo)) int {
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c.mu.Lock()
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m := c.counts[path]
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if m == nil {
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m = &minfo{}
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c.counts[path] = m
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}
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// if we are checking this path for the first time check to make sure
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// if it was already mounted on the system and make sure we have a correct ref
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// count if it is mounted as it is in use.
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if !m.check {
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m.check = true
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if c.checker.IsMounted(path) {
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m.count++
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}
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}
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infoOp(m)
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count := m.count
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if count <= 0 {
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delete(c.counts, path)
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}
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c.mu.Unlock()
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return count
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}
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