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William Dillon 2025-05-07 20:06:38 -04:00
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README.md Normal file
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# package apicontext
apicontext simply combines the context.Context with its corresponding context.CancelFunc,
making it simple to manage objects with context. It comes with some helper functiosn that
can replace infinite `for` loops (see `ContextIsNotDone`)

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apicontext.go Normal file
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package apicontext
import (
"context"
"time"
)
type Context struct {
ctx context.Context
cancel context.CancelFunc
}
func ContextIsDone(ctx context.Context) bool {
select {
case <-ctx.Done():
return true
default:
return false
}
}
func ContextIsNotDone(ctx context.Context) bool { return !ContextIsDone(ctx) }
func Background() context.Context { return context.Background() }
func (c *Context) Cancel() {
if c.cancel != nil {
c.cancel()
}
}
func (c *Context) Deadline() (deadline time.Time, ok bool) {
return c.ctx.Deadline()
}
func (c *Context) Done() <-chan struct{} {
return c.ctx.Done()
}
func (c *Context) Err() error {
return c.ctx.Err()
}
func (c *Context) Value(key any) any {
return c.ctx.Value(key)
}
func (c *Context) IsDone() bool {
return ContextIsDone(c.ctx)
}
func (c *Context) IsNotDone() bool {
return ContextIsNotDone(c.ctx)
}
// constructors
func WithCancel(parent context.Context) *Context {
ctx, cancel := context.WithCancel(parent)
return &Context{ctx: ctx, cancel: cancel}
}
func WithTimeout(parent context.Context, timeout time.Duration) *Context {
ctx, cancel := context.WithTimeout(parent, timeout)
return &Context{ctx: ctx, cancel: cancel}
}
func WithDeadline(parent context.Context, deadline time.Time) *Context {
ctx, cancel := context.WithDeadline(parent, deadline)
return &Context{ctx: ctx, cancel: cancel}
}
func WithValue(parent context.Context, key, val any) *Context {
ctx := context.WithValue(parent, key, val)
return &Context{ctx: ctx}
}

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apicontext_test.go Normal file
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package apicontext
import (
"context"
"errors"
"testing"
"time"
)
func TestContextIsDone(t *testing.T) {
ctx := WithCancel(Background())
defer ctx.Cancel()
if ContextIsDone(ctx) {
t.Fatalf("error: context was done before cancel()\n")
} else if err := ctx.Err(); err != nil {
t.Fatalf("error: context reporting error %v; expected nil\n", err)
}
ctx.Cancel()
if !ContextIsDone(ctx) {
t.Fatalf("error: context was not done after cancel()\n")
} else if want, got := context.Canceled, ctx.Err(); !errors.Is(got, want) {
t.Fatalf("error: wanted %v; got %v\n", want, got)
}
}
func TestContextWithTimeout(t *testing.T) {
timeout := time.Second
controlCtx, cancelControlCtx := context.WithTimeout(Background(), timeout*2)
defer cancelControlCtx()
ctx := WithTimeout(Background(), timeout)
defer ctx.Cancel()
if want, got := true, ctx.IsNotDone(); want != got {
t.Fatalf("error: wanted %v; got %v\n", want, got)
} else if want, got := error(nil), ctx.Err(); want != got {
t.Fatalf("error: wanted err == %v; got %v\n", want, got)
}
select {
case <-ctx.Done():
case <-controlCtx.Done():
t.Fatalf("error: control timeout reached - apicontext.WithTimeout failed to fire\n")
}
if want, got := true, ctx.IsDone(); want != got {
t.Fatalf("error: wanted %v; got %v\n", want, got)
} else if want, got := context.DeadlineExceeded, ctx.Err(); !errors.Is(got, want) {
t.Fatalf("error: wanted %v; got %v\n", want, got)
}
}
func TestContextWithDeadline(t *testing.T) {
deadline := time.Now().Add(time.Second)
controlCtx, cancelControlCtx := context.WithDeadline(Background(), deadline.Add(time.Second))
defer cancelControlCtx()
ctx := WithDeadline(Background(), deadline)
defer ctx.Cancel()
if gotDeadline, ok := ctx.Deadline(); !ok {
t.Fatalf("error: deadline !ok\n")
} else if want, got := deadline, gotDeadline; want != got {
t.Fatalf("error: wanted deadline %s; got %s\n", want, got)
} else if err := ctx.Err(); err != nil {
t.Fatalf("error: wanted err == nil; got %v\n", err)
}
select {
case <-ctx.Done():
case <-controlCtx.Done():
t.Fatalf("error: control timeout reached - apicontext.WithDeadline failed to fire\n")
}
if want, got := context.DeadlineExceeded, ctx.Err(); !errors.Is(got, want) {
t.Fatalf("error: wanted err == %v; got %v\n", want, got)
}
}
func TestContextWithValue(t *testing.T) {
type ValueKey string
key, value := ValueKey("TheTestKey"), "TheTestValue"
ctx := WithValue(Background(), key, value)
// expect no error from cancel
defer func() {
if err := recover(); err != nil {
t.Fatalf("error: expected no panic; got %s\n", err)
}
}()
ctx.Cancel()
if want, got := value, ctx.Value(key).(string); want != got {
t.Fatalf("error: wanted %s; got %s\n", want, got)
} else if err := ctx.Err(); err != nil {
t.Fatalf("error: got error from context...\n")
}
}

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go.mod Normal file
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module code.wmdillon.com/GoApi/apicontext
go 1.24.3