diff options
Diffstat (limited to 'vendor/golang.org/x/tools/internal/event/core/export.go')
-rw-r--r-- | vendor/golang.org/x/tools/internal/event/core/export.go | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/internal/event/core/export.go b/vendor/golang.org/x/tools/internal/event/core/export.go new file mode 100644 index 0000000..05f3a9a --- /dev/null +++ b/vendor/golang.org/x/tools/internal/event/core/export.go @@ -0,0 +1,70 @@ +// Copyright 2019 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. + +package core + +import ( + "context" + "sync/atomic" + "time" + "unsafe" + + "golang.org/x/tools/internal/event/label" +) + +// Exporter is a function that handles events. +// It may return a modified context and event. +type Exporter func(context.Context, Event, label.Map) context.Context + +var ( + exporter unsafe.Pointer +) + +// SetExporter sets the global exporter function that handles all events. +// The exporter is called synchronously from the event call site, so it should +// return quickly so as not to hold up user code. +func SetExporter(e Exporter) { + p := unsafe.Pointer(&e) + if e == nil { + // &e is always valid, and so p is always valid, but for the early abort + // of ProcessEvent to be efficient it needs to make the nil check on the + // pointer without having to dereference it, so we make the nil function + // also a nil pointer + p = nil + } + atomic.StorePointer(&exporter, p) +} + +// deliver is called to deliver an event to the supplied exporter. +// it will fill in the time. +func deliver(ctx context.Context, exporter Exporter, ev Event) context.Context { + // add the current time to the event + ev.at = time.Now() + // hand the event off to the current exporter + return exporter(ctx, ev, ev) +} + +// Export is called to deliver an event to the global exporter if set. +func Export(ctx context.Context, ev Event) context.Context { + // get the global exporter and abort early if there is not one + exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter)) + if exporterPtr == nil { + return ctx + } + return deliver(ctx, *exporterPtr, ev) +} + +// ExportPair is called to deliver a start event to the supplied exporter. +// It also returns a function that will deliver the end event to the same +// exporter. +// It will fill in the time. +func ExportPair(ctx context.Context, begin, end Event) (context.Context, func()) { + // get the global exporter and abort early if there is not one + exporterPtr := (*Exporter)(atomic.LoadPointer(&exporter)) + if exporterPtr == nil { + return ctx, func() {} + } + ctx = deliver(ctx, *exporterPtr, begin) + return ctx, func() { deliver(ctx, *exporterPtr, end) } +} |