111 lines
3.5 KiB
Go
111 lines
3.5 KiB
Go
// Copyright (c) 2019-2021 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package fx
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import (
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"fmt"
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"strings"
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"go.uber.org/fx/internal/fxreflect"
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)
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// Invoke registers functions that are executed eagerly on application start.
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// Arguments for these invocations are built using the constructors registered
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// by Provide. Passing multiple Invoke options appends the new invocations to
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// the application's existing list.
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//
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// Unlike constructors, invocations are always executed, and they're always
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// run in order. Invocations may have any number of returned values.
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// If the final returned object is an error, it indicates whether the operation
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// was successful.
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// All other returned values are discarded.
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//
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// Invokes registered in [Module]s are run before the ones registered at the
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// scope of the parent. Invokes within the same Module is run in the order
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// they were provided. For example,
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//
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// fx.New(
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// fx.Invoke(func3),
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// fx.Module("someModule",
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// fx.Invoke(func1),
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// fx.Invoke(func2),
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// ),
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// fx.Invoke(func4),
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// )
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//
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// invokes func1, func2, func3, func4 in that order.
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//
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// Typically, invoked functions take a handful of high-level objects (whose
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// constructors depend on lower-level objects) and introduce them to each
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// other. This kick-starts the application by forcing it to instantiate a
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// variety of types.
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//
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// To see an invocation in use, read through the package-level example. For
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// advanced features, including optional parameters and named instances, see
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// the documentation of the In and Out types.
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func Invoke(funcs ...interface{}) Option {
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return invokeOption{
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Targets: funcs,
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Stack: fxreflect.CallerStack(1, 0),
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}
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}
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type invokeOption struct {
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Targets []interface{}
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Stack fxreflect.Stack
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}
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func (o invokeOption) apply(mod *module) {
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for _, target := range o.Targets {
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mod.invokes = append(mod.invokes, invoke{
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Target: target,
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Stack: o.Stack,
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})
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}
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}
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func (o invokeOption) String() string {
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items := make([]string, len(o.Targets))
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for i, f := range o.Targets {
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items[i] = fxreflect.FuncName(f)
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}
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return fmt.Sprintf("fx.Invoke(%s)", strings.Join(items, ", "))
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}
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func runInvoke(c container, i invoke) error {
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fn := i.Target
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switch fn := fn.(type) {
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case Option:
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return fmt.Errorf("fx.Option should be passed to fx.New directly, "+
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"not to fx.Invoke: fx.Invoke received %v from:\n%+v",
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fn, i.Stack)
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case annotated:
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af, err := fn.Build()
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if err != nil {
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return err
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}
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return c.Invoke(af)
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default:
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return c.Invoke(fn)
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}
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}
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