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// Copyright 2016, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package gax
import (
"time"
"golang.org/x/net/context"
)
// A user defined call stub.
type APICall func(context.Context) error
// Invoke calls the given APICall,
// performing retries as specified by opts, if any.
func Invoke(ctx context.Context, call APICall, opts ...CallOption) error {
var settings CallSettings
for _, opt := range opts {
opt.Resolve(&settings)
}
return invoke(ctx, call, settings, Sleep)
}
// Sleep is similar to time.Sleep, but it can be interrupted by ctx.Done() closing.
// If interrupted, Sleep returns ctx.Err().
func Sleep(ctx context.Context, d time.Duration) error {
t := time.NewTimer(d)
select {
case <-ctx.Done():
t.Stop()
return ctx.Err()
case <-t.C:
return nil
}
}
type sleeper func(ctx context.Context, d time.Duration) error
// invoke implements Invoke, taking an additional sleeper argument for testing.
func invoke(ctx context.Context, call APICall, settings CallSettings, sp sleeper) error {
var retryer Retryer
for {
err := call(ctx)
if err == nil {
return nil
}
if settings.Retry == nil {
return err
}
if retryer == nil {
if r := settings.Retry(); r != nil {
retryer = r
} else {
return err
}
}
if d, ok := retryer.Retry(err); !ok {
return err
} else if err = sp(ctx, d); err != nil {
return err
}
}
}
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