syncthing/vendor/github.com/syndtr/goleveldb/leveldb/util/util.go
Jakob Borg 65aaa607ab Use Go 1.5 vendoring instead of Godeps
Change made by:

- running "gvt fetch" on each of the packages mentioned in
  Godeps/Godeps.json
- `rm -rf Godeps`
- tweaking the build scripts to not mention Godeps
- tweaking the build scripts to test `./lib/...`, `./cmd/...` explicitly
  (to avoid testing vendor)
- tweaking the build scripts to not juggle GOPATH for Godeps and instead
  set GO15VENDOREXPERIMENT.

This also results in some updated packages at the same time I bet.

Building with Go 1.3 and 1.4 still *works* but won't use our vendored
dependencies - the user needs to have the actual packages in their
GOPATH then, which they'll get with a normal "go get". Building with Go
1.6+ will get our vendored dependencies by default even when not using
our build script, which is nice.

By doing this we gain some freedom in that we can pick and choose
manually what to include in vendor, as it's not based on just dependency
analysis of our own code. This is also a risk as we might pick up
dependencies we are unaware of, as the build may work locally with those
packages present in GOPATH. On the other hand the build server will
detect this as it has no packages in it's GOPATH beyond what is included
in the repo.

Recommended tool to manage dependencies is github.com/FiloSottile/gvt.
2016-03-05 21:21:24 +01:00

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1.9 KiB
Go

// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com>
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Package util provides utilities used throughout leveldb.
package util
import (
"errors"
)
var (
ErrReleased = errors.New("leveldb: resource already relesed")
ErrHasReleaser = errors.New("leveldb: releaser already defined")
)
// Releaser is the interface that wraps the basic Release method.
type Releaser interface {
// Release releases associated resources. Release should always success
// and can be called multipe times without causing error.
Release()
}
// ReleaseSetter is the interface that wraps the basic SetReleaser method.
type ReleaseSetter interface {
// SetReleaser associates the given releaser to the resources. The
// releaser will be called once coresponding resources released.
// Calling SetReleaser with nil will clear the releaser.
//
// This will panic if a releaser already present or coresponding
// resource is already released. Releaser should be cleared first
// before assigned a new one.
SetReleaser(releaser Releaser)
}
// BasicReleaser provides basic implementation of Releaser and ReleaseSetter.
type BasicReleaser struct {
releaser Releaser
released bool
}
// Released returns whether Release method already called.
func (r *BasicReleaser) Released() bool {
return r.released
}
// Release implements Releaser.Release.
func (r *BasicReleaser) Release() {
if !r.released {
if r.releaser != nil {
r.releaser.Release()
r.releaser = nil
}
r.released = true
}
}
// SetReleaser implements ReleaseSetter.SetReleaser.
func (r *BasicReleaser) SetReleaser(releaser Releaser) {
if r.released {
panic(ErrReleased)
}
if r.releaser != nil && releaser != nil {
panic(ErrHasReleaser)
}
r.releaser = releaser
}
type NoopReleaser struct{}
func (NoopReleaser) Release() {}