From f6c22b4df92df1abc190d27427ba509cb92c1698 Mon Sep 17 00:00:00 2001
From: sugarme <thangtran@hotmail.com>
Date: Wed, 3 Jun 2020 12:07:08 +1000
Subject: [PATCH] fix(wrapper/error): fixed checking C pointer for null.
 WIP(example/error): testing TorchErr

---
 dtype.go              | 36 +++++++++++++++++++-----------------
 example/error/main.go | 32 ++++++++++++++++++++++++++++++++
 wrapper/error.go      | 22 +++++++++++-----------
 wrapper/tensor.go     | 14 +++++++++-----
 4 files changed, 71 insertions(+), 33 deletions(-)
 create mode 100644 example/error/main.go

diff --git a/dtype.go b/dtype.go
index 2761936..ef124b4 100644
--- a/dtype.go
+++ b/dtype.go
@@ -292,23 +292,25 @@ func TypeOf(dt DType, shape []int64) (retVal reflect.Type, err error) {
 	}
 }
 
-// TypeCheck checks whether data Go type matching DType
-func TypeCheck(data interface{}, dtype DType) (matched bool, msg string) {
-	dataValue := reflect.ValueOf(data)
-	var dataType reflect.Type
-	var err error
-	dataType, err = elementType(dataValue)
-	if err != nil {
-		msg = fmt.Sprintf("data type: %v, DType: %v\n", dataType, dtype.Kind())
-		msg += err.Error()
-		return false, msg
-	}
-
-	matched = dataType == dtype.Type
-	msg = fmt.Sprintf("data type: %v, DType: %v\n", dataType, dtype.Kind())
-
-	return matched, msg
-}
+/*
+ * // TypeCheck checks whether data Go type matching DType
+ * func TypeCheck(data interface{}, dtype DType) (matched bool, msg string) {
+ *   dataValue := reflect.ValueOf(data)
+ *   var dataType reflect.Type
+ *   var err error
+ *   dataType, err = elementType(dataValue)
+ *   if err != nil {
+ *     msg = fmt.Sprintf("data type: %v, DType: %v\n", dataType, dtype.Kind())
+ *     msg += err.Error()
+ *     return false, msg
+ *   }
+ *
+ *   matched = dataType == dtype.Type
+ *   msg = fmt.Sprintf("data type: %v, DType: %v\n", dataType, dtype.Kind())
+ *
+ *   return matched, msg
+ * }
+ *  */
 
 var supportedTypes = map[reflect.Kind]bool{
 	reflect.Uint8:   true,
diff --git a/example/error/main.go b/example/error/main.go
new file mode 100644
index 0000000..34f3839
--- /dev/null
+++ b/example/error/main.go
@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	wrapper "github.com/sugarme/gotch/wrapper"
+)
+
+func main() {
+
+	// Try to compare 2 tensor with incompatible dimensions
+	// and check this returns an error
+	dx := []int32{1, 2, 3}
+	dy := []int32{1, 2, 3, 4}
+
+	xs, err := wrapper.OfSlice(dx)
+	if err != nil {
+		log.Fatal(err)
+	}
+	ys, err := wrapper.OfSlice(dy)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	xs.Print()
+	ys.Print()
+
+	fmt.Printf("xs dim: %v\n", xs.Dim())
+	fmt.Printf("ys dim: %v\n", ys.Dim())
+
+}
diff --git a/wrapper/error.go b/wrapper/error.go
index 2a59523..99104e6 100644
--- a/wrapper/error.go
+++ b/wrapper/error.go
@@ -10,23 +10,23 @@ import (
 	lib "github.com/sugarme/gotch/libtch"
 )
 
-// ptrToString returns nil on the null pointer. If not null,
-// the pointer gets freed.
+// ptrToString check C pointer for null. If not null, get value
+// the pointer points to and frees up C memory. It is used for
+// getting error message C pointer points to and clean up C memory.
+//
 // NOTE: C does not have exception design. C++ throws exception
 // to stderr. This code to check stderr for any err message,
-// if it exists, takes it and frees up C pointer.
+// if it exists, takes it and frees up C memory.
 func ptrToString(cptr *C.char) string {
-	var str string
+	var str string = ""
 
-	str = *(*string)(unsafe.Pointer(&cptr))
-	fmt.Printf("Err Msg from C: %v\n", str)
-	if str != "" {
-		// Free up C memory
+	if cptr != nil {
+		str = *(*string)(unsafe.Pointer(&cptr))
+		fmt.Printf("Err Msg from C: %v\n", str)
 		C.free(unsafe.Pointer(cptr))
-		return str
-	} else {
-		return ""
 	}
+
+	return str
 }
 
 // TorchErr checks and retrieves last error message from
diff --git a/wrapper/tensor.go b/wrapper/tensor.go
index 163cc6d..5520a9a 100644
--- a/wrapper/tensor.go
+++ b/wrapper/tensor.go
@@ -128,15 +128,19 @@ func decodeSize(ptr unsafe.Pointer, nsize uint64) []int64 {
 //
 // }
 
-// FOfSlice creates tensor from a slice data
-func (ts Tensor) FOfSlice(data interface{}, dtype gotch.DType) (retVal *Tensor, err error) {
+// OfSlice creates tensor from a slice data
+func OfSlice(data interface{}) (retVal *Tensor, err error) {
 
-	if ok, msg := gotch.TypeCheck(data, dtype); !ok {
-		err = fmt.Errorf("data type and DType are mismatched: %v\n", msg)
+	typ, dataLen, err := DataCheck(data)
+	if err != nil {
+		return nil, err
+	}
+
+	dtype, err := gotch.ToDType(typ)
+	if err != nil {
 		return nil, err
 	}
 
-	dataLen := reflect.ValueOf(data).Len()
 	shape := []int64{int64(dataLen)}
 	elementNum := ElementCount(shape)