site/vendor/github.com/magefile/mage/mg/deps.go

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2017-12-13 18:43:58 +00:00
package mg
import (
"context"
"fmt"
"reflect"
"runtime"
"strings"
"sync"
"github.com/magefile/mage/types"
)
type onceMap struct {
mu *sync.Mutex
m map[string]*onceFun
}
func (o *onceMap) LoadOrStore(s string, one *onceFun) *onceFun {
defer o.mu.Unlock()
o.mu.Lock()
existing, ok := o.m[s]
if ok {
return existing
}
o.m[s] = one
return one
}
var onces = &onceMap{
mu: &sync.Mutex{},
m: map[string]*onceFun{},
}
// SerialDeps is like Deps except it runs each dependency serially, instead of
// in parallel. This can be useful for resource intensive dependencies that
// shouldn't be run at the same time.
func SerialDeps(fns ...interface{}) {
checkFns(fns)
ctx := context.Background()
for _, f := range fns {
runDeps(ctx, f)
}
}
// SerialCtxDeps is like CtxDeps except it runs each dependency serially,
// instead of in parallel. This can be useful for resource intensive
// dependencies that shouldn't be run at the same time.
func SerialCtxDeps(ctx context.Context, fns ...interface{}) {
checkFns(fns)
for _, f := range fns {
runDeps(ctx, f)
}
}
// CtxDeps runs the given functions as dependencies of the calling function.
// Dependencies must only be of type: github.com/magefile/mage/types.FuncType.
// The function calling Deps is guaranteed that all dependent functions will be
// run exactly once when Deps returns. Dependent functions may in turn declare
// their own dependencies using Deps. Each dependency is run in their own
// goroutines. Each function is given the context provided if the function
// prototype allows for it.
func CtxDeps(ctx context.Context, fns ...interface{}) {
checkFns(fns)
runDeps(ctx, fns...)
}
// runDeps assumes you've already called checkFns.
func runDeps(ctx context.Context, fns ...interface{}) {
mu := &sync.Mutex{}
var errs []string
var exit int
wg := &sync.WaitGroup{}
for _, f := range fns {
fn := addDep(ctx, f)
wg.Add(1)
go func() {
defer func() {
if v := recover(); v != nil {
mu.Lock()
if err, ok := v.(error); ok {
exit = changeExit(exit, ExitStatus(err))
} else {
exit = changeExit(exit, 1)
}
errs = append(errs, fmt.Sprint(v))
mu.Unlock()
}
wg.Done()
}()
if err := fn.run(); err != nil {
mu.Lock()
errs = append(errs, fmt.Sprint(err))
exit = changeExit(exit, ExitStatus(err))
mu.Unlock()
}
}()
}
wg.Wait()
if len(errs) > 0 {
panic(Fatal(exit, strings.Join(errs, "\n")))
}
}
func checkFns(fns []interface{}) {
for _, f := range fns {
if err := types.FuncCheck(f); err != nil {
panic(err)
}
}
}
// Deps runs the given functions with the default runtime context
func Deps(fns ...interface{}) {
CtxDeps(context.Background(), fns...)
}
func changeExit(old, new int) int {
if new == 0 {
return old
}
if old == 0 {
return new
}
if old == new {
return old
}
// both different and both non-zero, just set
// exit to 1. Nothing more we can do.
return 1
}
func addDep(ctx context.Context, f interface{}) *onceFun {
var fn func(context.Context) error
if fn = types.FuncTypeWrap(f); fn == nil {
// should be impossible, since we already checked this
panic("attempted to add a dep that did not match required type")
}
n := name(f)
of := onces.LoadOrStore(n, &onceFun{
fn: fn,
ctx: ctx,
})
return of
}
func name(i interface{}) string {
return runtime.FuncForPC(reflect.ValueOf(i).Pointer()).Name()
}
type onceFun struct {
once sync.Once
fn func(context.Context) error
ctx context.Context
}
func (o *onceFun) run() error {
var err error
o.once.Do(func() {
err = o.fn(o.ctx)
})
return err
}