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https://github.com/golang/go
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a466788a31
This was the last piece of Event that was public, and it was only public to allow mutation in tests. Adding CloneEvent allows tests to create an updated copy rather than update the event in place. Change-Id: I2215d1eb0317063948ef0fac955fa768a209564d Reviewed-on: https://go-review.googlesource.com/c/tools/+/229241 Run-TryBot: Ian Cottrell <iancottrell@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
71 lines
2.2 KiB
Go
71 lines
2.2 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package core
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import (
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"context"
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"sync/atomic"
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"time"
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"unsafe"
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"golang.org/x/tools/internal/event/label"
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)
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// Exporter is a function that handles events.
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// It may return a modified context and event.
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type Exporter func(context.Context, Event, label.Map) context.Context
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var (
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exporter unsafe.Pointer
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)
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// SetExporter sets the global exporter function that handles all events.
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// The exporter is called synchronously from the event call site, so it should
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// return quickly so as not to hold up user code.
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func SetExporter(e Exporter) {
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p := unsafe.Pointer(&e)
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if e == nil {
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// &e is always valid, and so p is always valid, but for the early abort
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// of ProcessEvent to be efficient it needs to make the nil check on the
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// pointer without having to dereference it, so we make the nil function
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// also a nil pointer
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p = nil
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}
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atomic.StorePointer(&exporter, p)
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}
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// deliver is called to deliver an event to the supplied exporter.
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// it will fill in the time.
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func deliver(ctx context.Context, exporter Exporter, ev Event) context.Context {
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// add the current time to the event
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ev.at = time.Now()
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// hand the event off to the current exporter
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return exporter(ctx, ev, ev)
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}
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// Export is called to deliver an event to the global exporter if set.
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func Export(ctx context.Context, ev Event) context.Context {
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// get the global exporter and abort early if there is not one
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exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter))
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if exporterPtr == nil {
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return ctx
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}
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return deliver(ctx, *exporterPtr, ev)
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}
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// ExportPair is called to deliver a start event to the supplied exporter.
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// It also returns a function that will deliver the end event to the same
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// exporter.
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// It will fill in the time.
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func ExportPair(ctx context.Context, begin, end Event) (context.Context, func()) {
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// get the global exporter and abort early if there is not one
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exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter))
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if exporterPtr == nil {
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return ctx, func() {}
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}
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ctx = deliver(ctx, *exporterPtr, begin)
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return ctx, func() { deliver(ctx, *exporterPtr, end) }
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}
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