ODPM 266: Go-libmemif + 2 examples.

Change-Id: Icdb9b9eb2314eff6c96afe7996fcf2728291de4a
Signed-off-by: Milan Lenco <milan.lenco@pantheon.tech>

1 files changed, 123 insertions, 0 deletions

diff --git a/extras/libmemif/error.go b/extras/libmemif/error.go
new file mode 100644
index 0000000..3a2145d
--- /dev/null
+++ b/extras/libmemif/error.go
@@ -0,0 +1,123 @@
+// Copyright (c) 2017 Cisco and/or its affiliates.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !windows,!darwin
+
+package libmemif
+
+/*
+#cgo LDFLAGS: -lmemif
+
+#include <unistd.h>
+#include <libmemif.h>
+*/
+import "C"
+
+// List of errors thrown by go-libmemif.
+// Error handling code should compare returned error by value against these variables.
+var (
+	ErrSyscall       = newMemifError(1)
+	ErrAccess        = newMemifError(2)
+	ErrNoFile        = newMemifError(3)
+	ErrFileLimit     = newMemifError(4)
+	ErrProcFileLimit = newMemifError(5)
+	ErrAlready       = newMemifError(6)
+	ErrAgain         = newMemifError(7)
+	ErrBadFd         = newMemifError(8)
+	ErrNoMem         = newMemifError(9)
+	ErrInvalArgs     = newMemifError(10)
+	ErrNoConn        = newMemifError(11)
+	ErrConn          = newMemifError(12)
+	ErrClbFDUpdate   = newMemifError(13)
+	ErrFileNotSock   = newMemifError(14)
+	ErrNoShmFD       = newMemifError(15)
+	ErrCookie        = newMemifError(16)
+
+	// Not thrown, instead properly handled inside the golang adapter:
+	ErrNoBufRing    = newMemifError(17)
+	ErrNoBuf        = newMemifError(18)
+	ErrNoBufDetails = newMemifError(19)
+
+	ErrIntWrite     = newMemifError(20)
+	ErrMalformedMsg = newMemifError(21)
+	ErrQueueID      = newMemifError(22)
+	ErrProto        = newMemifError(23)
+	ErrIfID         = newMemifError(24)
+	ErrAcceptSlave  = newMemifError(25)
+	ErrAlreadyConn  = newMemifError(26)
+	ErrMode         = newMemifError(27)
+	ErrSecret       = newMemifError(28)
+	ErrNoSecret     = newMemifError(29)
+	ErrMaxRegion    = newMemifError(30)
+	ErrMaxRing      = newMemifError(31)
+	ErrNotIntFD     = newMemifError(32)
+	ErrDisconnect   = newMemifError(33)
+	ErrDisconnected = newMemifError(34)
+	ErrUnknownMsg   = newMemifError(35)
+	ErrPollCanceled = newMemifError(36)
+
+	// Errors added by the adapter:
+	ErrNotInit     = newMemifError(100, "libmemif is not initialized")
+	ErrAlreadyInit = newMemifError(101, "libmemif is already initialized")
+	ErrUnsupported = newMemifError(102, "the feature is not supported by C-libmemif")
+
+	// Received unrecognized error code from C-libmemif.
+	ErrUnknown = newMemifError(-1, "unknown error")
+)
+
+// MemifError implements and extends the error interface with the method Code(),
+// which returns the integer error code as returned by C-libmemif.
+type MemifError struct {
+	code        int
+	description string
+}
+
+// Error prints error description.
+func (e *MemifError) Error() string {
+	return e.description
+}
+
+// Code returns the integer error code as returned by C-libmemif.
+func (e *MemifError) Code() int {
+	return e.code
+}
+
+// A registry of libmemif errors. Used to convert C-libmemif error code into
+// the associated MemifError.
+var errorRegistry = map[int]*MemifError{}
+
+// newMemifError builds and registers a new MemifError.
+func newMemifError(code int, desc ...string) *MemifError {
+	var err *MemifError
+	if len(desc) > 0 {
+		err = &MemifError{code: code, description: "libmemif: " + desc[0]}
+	} else {
+		err = &MemifError{code: code, description: "libmemif: " + C.GoString(C.memif_strerror(C.int(code)))}
+	}
+	errorRegistry[code] = err
+	return err
+}
+
+// getMemifError returns the MemifError associated with the given C-libmemif
+// error code.
+func getMemifError(code int) error {
+	if code == 0 {
+		return nil /* success */
+	}
+	err, known := errorRegistry[code]
+	if !known {
+		return ErrUnknown
+	}
+	return err
+}