Export etw package

pkg/etw/providerglobal.go

@@ -0,0 +1,52 @@
+package etw
+
+import (
+	"sync"
+)
+
+// Because the provider callback function needs to be able to access the
+// provider data when it is invoked by ETW, we need to keep provider data stored
+// in a global map based on an index. The index is passed as the callback
+// context to ETW.
+type providerMap struct {
+	m    map[uint]*Provider
+	i    uint
+	lock sync.Mutex
+	once sync.Once
+}
+
+var providers = providerMap{
+	m: make(map[uint]*Provider),
+}
+
+func (p *providerMap) newProvider() *Provider {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	i := p.i
+	p.i++
+
+	provider := &Provider{
+		index: i,
+	}
+
+	p.m[i] = provider
+	return provider
+}
+
+func (p *providerMap) removeProvider(provider *Provider) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	delete(p.m, provider.index)
+}
+
+func (p *providerMap) getProvider(index uint) *Provider {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	return p.m[index]
+}
+
+var providerCallbackOnce sync.Once
+var globalProviderCallback uintptr