1 files changed, 85 insertions, 0 deletions
diff --git a/vendor/github.com/docker/distribution/context/context.go b/vendor/github.com/docker/distribution/context/context.go
new file mode 100644
index 000000000..23cbf5b54
--- /dev/null
+++ b/vendor/github.com/docker/distribution/context/context.go
@@ -0,0 +1,85 @@
+package context
+
+import (
+	"sync"
+
+	"github.com/docker/distribution/uuid"
+	"golang.org/x/net/context"
+)
+
+// Context is a copy of Context from the golang.org/x/net/context package.
+type Context interface {
+	context.Context
+}
+
+// instanceContext is a context that provides only an instance id. It is
+// provided as the main background context.
+type instanceContext struct {
+	Context
+	id   string    // id of context, logged as "instance.id"
+	once sync.Once // once protect generation of the id
+}
+
+func (ic *instanceContext) Value(key interface{}) interface{} {
+	if key == "instance.id" {
+		ic.once.Do(func() {
+			// We want to lazy initialize the UUID such that we don't
+			// call a random generator from the package initialization
+			// code. For various reasons random could not be available
+			// https://github.com/docker/distribution/issues/782
+			ic.id = uuid.Generate().String()
+		})
+		return ic.id
+	}
+
+	return ic.Context.Value(key)
+}
+
+var background = &instanceContext{
+	Context: context.Background(),
+}
+
+// Background returns a non-nil, empty Context. The background context
+// provides a single key, "instance.id" that is globally unique to the
+// process.
+func Background() Context {
+	return background
+}
+
+// WithValue returns a copy of parent in which the value associated with key is
+// val. Use context Values only for request-scoped data that transits processes
+// and APIs, not for passing optional parameters to functions.
+func WithValue(parent Context, key, val interface{}) Context {
+	return context.WithValue(parent, key, val)
+}
+
+// stringMapContext is a simple context implementation that checks a map for a
+// key, falling back to a parent if not present.
+type stringMapContext struct {
+	context.Context
+	m map[string]interface{}
+}
+
+// WithValues returns a context that proxies lookups through a map. Only
+// supports string keys.
+func WithValues(ctx context.Context, m map[string]interface{}) context.Context {
+	mo := make(map[string]interface{}, len(m)) // make our own copy.
+	for k, v := range m {
+		mo[k] = v
+	}
+
+	return stringMapContext{
+		Context: ctx,
+		m:       mo,
+	}
+}
+
+func (smc stringMapContext) Value(key interface{}) interface{} {
+	if ks, ok := key.(string); ok {
+		if v, ok := smc.m[ks]; ok {
+			return v
+		}
+	}
+
+	return smc.Context.Value(key)
+}