1 files changed, 102 insertions, 0 deletions
diff --git a/src/dma/vendor/github.com/libvirt/libvirt-go/callbacks.go b/src/dma/vendor/github.com/libvirt/libvirt-go/callbacks.go
new file mode 100644
index 00000000..7b2d11ba
--- /dev/null
+++ b/src/dma/vendor/github.com/libvirt/libvirt-go/callbacks.go
@@ -0,0 +1,102 @@
+/*
+ * This file is part of the libvirt-go project
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * Copyright (c) 2013 Alex Zorin
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ */
+
+package libvirt
+
+// Helpers functions to register a Go callback function to a C
+// function. For a simple example, look at how SetErrorFunc works in
+// error.go.
+//
+// - Create a struct that will contain at least the Go callback to
+//   invoke (errorContext).
+//
+// - Create an exported Golang function whose job will be to retrieve
+//   the context and execute the callback in it
+//   (connErrCallback). Such a function should receive a callback ID
+//   and will use it to retrive the context.
+//
+// - Create a CGO function similar to the above function but with the
+//   appropriate signature to be registered as a callback in C code
+//   (connErrCallbackHelper). Notably, it will have a void* argument
+//   that should be cast to long to retrieve the callback ID. It
+//   should be just a thin wrapper to transform the opaque argument to
+//   a callback ID.
+//
+// - Create a CGO function which will be a wrapper around the C
+//   function to register the callback (virConnSetErrorFuncWrapper). Its
+//   only role is to transform a callback ID (long) to an opaque (void*)
+//   and call the C function.
+//
+// - When setting up a callback (SetErrorFunc), register the struct from first step
+//   with registerCallbackId and invoke the CGO function from the
+//   previous step with the appropriate ID.
+//
+// - When unregistering the callback, don't forget to call freecallbackId.
+//
+// If you need to associate some additional data with the connection,
+// look at saveConnectionData, getConnectionData and
+// releaseConnectionData.
+
+import "C"
+
+import (
+	"sync"
+)
+
+const firstGoCallbackId int = 100 // help catch some additional errors during test
+var goCallbackLock sync.RWMutex
+var goCallbacks = make(map[int]interface{})
+var nextGoCallbackId int = firstGoCallbackId
+
+//export freeCallbackId
+func freeCallbackId(goCallbackId int) {
+	goCallbackLock.Lock()
+	delete(goCallbacks, goCallbackId)
+	goCallbackLock.Unlock()
+}
+
+func getCallbackId(goCallbackId int) interface{} {
+	goCallbackLock.RLock()
+	ctx := goCallbacks[goCallbackId]
+	goCallbackLock.RUnlock()
+	if ctx == nil {
+		// If this happens there must be a bug in libvirt
+		panic("Callback arrived after freeCallbackId was called")
+	}
+	return ctx
+}
+
+func registerCallbackId(ctx interface{}) int {
+	goCallbackLock.Lock()
+	goCallBackId := nextGoCallbackId
+	nextGoCallbackId++
+	for goCallbacks[nextGoCallbackId] != nil {
+		nextGoCallbackId++
+	}
+	goCallbacks[goCallBackId] = ctx
+	goCallbackLock.Unlock()
+	return goCallBackId
+}