Vendor dependencies with dep

vendor/github.com/minio/minio-go/pkg/credentials/credentials.go

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+/*
+ * Minio Go Library for Amazon S3 Compatible Cloud Storage
+ * (C) 2017 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package credentials
+
+import (
+	"sync"
+	"time"
+)
+
+// A Value is the AWS credentials value for individual credential fields.
+type Value struct {
+	// AWS Access key ID
+	AccessKeyID string
+
+	// AWS Secret Access Key
+	SecretAccessKey string
+
+	// AWS Session Token
+	SessionToken string
+
+	// Signature Type.
+	SignerType SignatureType
+}
+
+// A Provider is the interface for any component which will provide credentials
+// Value. A provider is required to manage its own Expired state, and what to
+// be expired means.
+type Provider interface {
+	// Retrieve returns nil if it successfully retrieved the value.
+	// Error is returned if the value were not obtainable, or empty.
+	Retrieve() (Value, error)
+
+	// IsExpired returns if the credentials are no longer valid, and need
+	// to be retrieved.
+	IsExpired() bool
+}
+
+// A Expiry provides shared expiration logic to be used by credentials
+// providers to implement expiry functionality.
+//
+// The best method to use this struct is as an anonymous field within the
+// provider's struct.
+//
+// Example:
+//     type IAMCredentialProvider struct {
+//         Expiry
+//         ...
+//     }
+type Expiry struct {
+	// The date/time when to expire on
+	expiration time.Time
+
+	// If set will be used by IsExpired to determine the current time.
+	// Defaults to time.Now if CurrentTime is not set.
+	CurrentTime func() time.Time
+}
+
+// SetExpiration sets the expiration IsExpired will check when called.
+//
+// If window is greater than 0 the expiration time will be reduced by the
+// window value.
+//
+// Using a window is helpful to trigger credentials to expire sooner than
+// the expiration time given to ensure no requests are made with expired
+// tokens.
+func (e *Expiry) SetExpiration(expiration time.Time, window time.Duration) {
+	e.expiration = expiration
+	if window > 0 {
+		e.expiration = e.expiration.Add(-window)
+	}
+}
+
+// IsExpired returns if the credentials are expired.
+func (e *Expiry) IsExpired() bool {
+	if e.CurrentTime == nil {
+		e.CurrentTime = time.Now
+	}
+	return e.expiration.Before(e.CurrentTime())
+}
+
+// Credentials - A container for synchronous safe retrieval of credentials Value.
+// Credentials will cache the credentials value until they expire. Once the value
+// expires the next Get will attempt to retrieve valid credentials.
+//
+// Credentials is safe to use across multiple goroutines and will manage the
+// synchronous state so the Providers do not need to implement their own
+// synchronization.
+//
+// The first Credentials.Get() will always call Provider.Retrieve() to get the
+// first instance of the credentials Value. All calls to Get() after that
+// will return the cached credentials Value until IsExpired() returns true.
+type Credentials struct {
+	sync.Mutex
+
+	creds        Value
+	forceRefresh bool
+	provider     Provider
+}
+
+// New returns a pointer to a new Credentials with the provider set.
+func New(provider Provider) *Credentials {
+	return &Credentials{
+		provider:     provider,
+		forceRefresh: true,
+	}
+}
+
+// Get returns the credentials value, or error if the credentials Value failed
+// to be retrieved.
+//
+// Will return the cached credentials Value if it has not expired. If the
+// credentials Value has expired the Provider's Retrieve() will be called
+// to refresh the credentials.
+//
+// If Credentials.Expire() was called the credentials Value will be force
+// expired, and the next call to Get() will cause them to be refreshed.
+func (c *Credentials) Get() (Value, error) {
+	c.Lock()
+	defer c.Unlock()
+
+	if c.isExpired() {
+		creds, err := c.provider.Retrieve()
+		if err != nil {
+			return Value{}, err
+		}
+		c.creds = creds
+		c.forceRefresh = false
+	}
+
+	return c.creds, nil
+}
+
+// Expire expires the credentials and forces them to be retrieved on the
+// next call to Get().
+//
+// This will override the Provider's expired state, and force Credentials
+// to call the Provider's Retrieve().
+func (c *Credentials) Expire() {
+	c.Lock()
+	defer c.Unlock()
+
+	c.forceRefresh = true
+}
+
+// IsExpired returns if the credentials are no longer valid, and need
+// to be refreshed.
+//
+// If the Credentials were forced to be expired with Expire() this will
+// reflect that override.
+func (c *Credentials) IsExpired() bool {
+	c.Lock()
+	defer c.Unlock()
+
+	return c.isExpired()
+}
+
+// isExpired helper method wrapping the definition of expired credentials.
+func (c *Credentials) isExpired() bool {
+	return c.forceRefresh || c.provider.IsExpired()
+}