aboutsummaryrefslogtreecommitdiff
path: root/vendor/golang.org/x/net/context/pre_go17.go
diff options
context:
space:
mode:
Diffstat (limited to 'vendor/golang.org/x/net/context/pre_go17.go')
-rw-r--r--vendor/golang.org/x/net/context/pre_go17.go300
1 files changed, 0 insertions, 300 deletions
diff --git a/vendor/golang.org/x/net/context/pre_go17.go b/vendor/golang.org/x/net/context/pre_go17.go
deleted file mode 100644
index 0f35592..0000000
--- a/vendor/golang.org/x/net/context/pre_go17.go
+++ /dev/null
@@ -1,300 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !go1.7
-
-package context
-
-import (
- "errors"
- "fmt"
- "sync"
- "time"
-)
-
-// An emptyCtx is never canceled, has no values, and has no deadline. It is not
-// struct{}, since vars of this type must have distinct addresses.
-type emptyCtx int
-
-func (*emptyCtx) Deadline() (deadline time.Time, ok bool) {
- return
-}
-
-func (*emptyCtx) Done() <-chan struct{} {
- return nil
-}
-
-func (*emptyCtx) Err() error {
- return nil
-}
-
-func (*emptyCtx) Value(key interface{}) interface{} {
- return nil
-}
-
-func (e *emptyCtx) String() string {
- switch e {
- case background:
- return "context.Background"
- case todo:
- return "context.TODO"
- }
- return "unknown empty Context"
-}
-
-var (
- background = new(emptyCtx)
- todo = new(emptyCtx)
-)
-
-// Canceled is the error returned by Context.Err when the context is canceled.
-var Canceled = errors.New("context canceled")
-
-// DeadlineExceeded is the error returned by Context.Err when the context's
-// deadline passes.
-var DeadlineExceeded = errors.New("context deadline exceeded")
-
-// WithCancel returns a copy of parent with a new Done channel. The returned
-// context's Done channel is closed when the returned cancel function is called
-// or when the parent context's Done channel is closed, whichever happens first.
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete.
-func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
- c := newCancelCtx(parent)
- propagateCancel(parent, c)
- return c, func() { c.cancel(true, Canceled) }
-}
-
-// newCancelCtx returns an initialized cancelCtx.
-func newCancelCtx(parent Context) *cancelCtx {
- return &cancelCtx{
- Context: parent,
- done: make(chan struct{}),
- }
-}
-
-// propagateCancel arranges for child to be canceled when parent is.
-func propagateCancel(parent Context, child canceler) {
- if parent.Done() == nil {
- return // parent is never canceled
- }
- if p, ok := parentCancelCtx(parent); ok {
- p.mu.Lock()
- if p.err != nil {
- // parent has already been canceled
- child.cancel(false, p.err)
- } else {
- if p.children == nil {
- p.children = make(map[canceler]bool)
- }
- p.children[child] = true
- }
- p.mu.Unlock()
- } else {
- go func() {
- select {
- case <-parent.Done():
- child.cancel(false, parent.Err())
- case <-child.Done():
- }
- }()
- }
-}
-
-// parentCancelCtx follows a chain of parent references until it finds a
-// *cancelCtx. This function understands how each of the concrete types in this
-// package represents its parent.
-func parentCancelCtx(parent Context) (*cancelCtx, bool) {
- for {
- switch c := parent.(type) {
- case *cancelCtx:
- return c, true
- case *timerCtx:
- return c.cancelCtx, true
- case *valueCtx:
- parent = c.Context
- default:
- return nil, false
- }
- }
-}
-
-// removeChild removes a context from its parent.
-func removeChild(parent Context, child canceler) {
- p, ok := parentCancelCtx(parent)
- if !ok {
- return
- }
- p.mu.Lock()
- if p.children != nil {
- delete(p.children, child)
- }
- p.mu.Unlock()
-}
-
-// A canceler is a context type that can be canceled directly. The
-// implementations are *cancelCtx and *timerCtx.
-type canceler interface {
- cancel(removeFromParent bool, err error)
- Done() <-chan struct{}
-}
-
-// A cancelCtx can be canceled. When canceled, it also cancels any children
-// that implement canceler.
-type cancelCtx struct {
- Context
-
- done chan struct{} // closed by the first cancel call.
-
- mu sync.Mutex
- children map[canceler]bool // set to nil by the first cancel call
- err error // set to non-nil by the first cancel call
-}
-
-func (c *cancelCtx) Done() <-chan struct{} {
- return c.done
-}
-
-func (c *cancelCtx) Err() error {
- c.mu.Lock()
- defer c.mu.Unlock()
- return c.err
-}
-
-func (c *cancelCtx) String() string {
- return fmt.Sprintf("%v.WithCancel", c.Context)
-}
-
-// cancel closes c.done, cancels each of c's children, and, if
-// removeFromParent is true, removes c from its parent's children.
-func (c *cancelCtx) cancel(removeFromParent bool, err error) {
- if err == nil {
- panic("context: internal error: missing cancel error")
- }
- c.mu.Lock()
- if c.err != nil {
- c.mu.Unlock()
- return // already canceled
- }
- c.err = err
- close(c.done)
- for child := range c.children {
- // NOTE: acquiring the child's lock while holding parent's lock.
- child.cancel(false, err)
- }
- c.children = nil
- c.mu.Unlock()
-
- if removeFromParent {
- removeChild(c.Context, c)
- }
-}
-
-// WithDeadline returns a copy of the parent context with the deadline adjusted
-// to be no later than d. If the parent's deadline is already earlier than d,
-// WithDeadline(parent, d) is semantically equivalent to parent. The returned
-// context's Done channel is closed when the deadline expires, when the returned
-// cancel function is called, or when the parent context's Done channel is
-// closed, whichever happens first.
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete.
-func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
- if cur, ok := parent.Deadline(); ok && cur.Before(deadline) {
- // The current deadline is already sooner than the new one.
- return WithCancel(parent)
- }
- c := &timerCtx{
- cancelCtx: newCancelCtx(parent),
- deadline: deadline,
- }
- propagateCancel(parent, c)
- d := deadline.Sub(time.Now())
- if d <= 0 {
- c.cancel(true, DeadlineExceeded) // deadline has already passed
- return c, func() { c.cancel(true, Canceled) }
- }
- c.mu.Lock()
- defer c.mu.Unlock()
- if c.err == nil {
- c.timer = time.AfterFunc(d, func() {
- c.cancel(true, DeadlineExceeded)
- })
- }
- return c, func() { c.cancel(true, Canceled) }
-}
-
-// A timerCtx carries a timer and a deadline. It embeds a cancelCtx to
-// implement Done and Err. It implements cancel by stopping its timer then
-// delegating to cancelCtx.cancel.
-type timerCtx struct {
- *cancelCtx
- timer *time.Timer // Under cancelCtx.mu.
-
- deadline time.Time
-}
-
-func (c *timerCtx) Deadline() (deadline time.Time, ok bool) {
- return c.deadline, true
-}
-
-func (c *timerCtx) String() string {
- return fmt.Sprintf("%v.WithDeadline(%s [%s])", c.cancelCtx.Context, c.deadline, c.deadline.Sub(time.Now()))
-}
-
-func (c *timerCtx) cancel(removeFromParent bool, err error) {
- c.cancelCtx.cancel(false, err)
- if removeFromParent {
- // Remove this timerCtx from its parent cancelCtx's children.
- removeChild(c.cancelCtx.Context, c)
- }
- c.mu.Lock()
- if c.timer != nil {
- c.timer.Stop()
- c.timer = nil
- }
- c.mu.Unlock()
-}
-
-// WithTimeout returns WithDeadline(parent, time.Now().Add(timeout)).
-//
-// Canceling this context releases resources associated with it, so code should
-// call cancel as soon as the operations running in this Context complete:
-//
-// func slowOperationWithTimeout(ctx context.Context) (Result, error) {
-// ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
-// defer cancel() // releases resources if slowOperation completes before timeout elapses
-// return slowOperation(ctx)
-// }
-func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
- return WithDeadline(parent, time.Now().Add(timeout))
-}
-
-// 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 interface{}, val interface{}) Context {
- return &valueCtx{parent, key, val}
-}
-
-// A valueCtx carries a key-value pair. It implements Value for that key and
-// delegates all other calls to the embedded Context.
-type valueCtx struct {
- Context
- key, val interface{}
-}
-
-func (c *valueCtx) String() string {
- return fmt.Sprintf("%v.WithValue(%#v, %#v)", c.Context, c.key, c.val)
-}
-
-func (c *valueCtx) Value(key interface{}) interface{} {
- if c.key == key {
- return c.val
- }
- return c.Context.Value(key)
-}