From ec31313bc276d9b6569606bf5e3e8adacf6c4295 Mon Sep 17 00:00:00 2001
From: Jae Kwon <jae@tendermint.com>
Date: Wed, 29 Nov 2017 21:27:03 -0800
Subject: [PATCH] Add errors

---
 errors/errors.go | 134 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 errors/errors.go

diff --git a/errors/errors.go b/errors/errors.go
new file mode 100644
index 0000000000..9e6e649a48
--- /dev/null
+++ b/errors/errors.go
@@ -0,0 +1,134 @@
+package errors
+
+import "fmt"
+
+const (
+	// ABCI Response Codes
+	CodeInternalError     = 1
+	CodeEncodingError     = 2
+	CodeBadNonce          = 3
+	CodeUnauthorized      = 4
+	CodeInsufficientFunds = 5
+	CodeUnknownRequest    = 6
+)
+
+// NOTE: Don't stringer this, we'll put better messages in later.
+func codeToDefaultLog(code uint32) string {
+	switch code {
+	case CodeInternalError:
+		return "Internal error"
+	case CodeEncodingError:
+		return "Encoding error"
+	case CodeBadNonce:
+		return "Bad nonce"
+	case CodeUnauthorized:
+		return "Unauthorized"
+	case CodeInsufficientFunds:
+		return "Insufficent funds"
+	case CodeUnknownRequest:
+		return "Unknown request"
+	default:
+		return fmt.Sprintf("Unknown code %d", code)
+	}
+}
+
+//--------------------------------------------------------------------------------
+// All errors are created via constructors so as to enable us to hijack them
+// and inject stack traces if we really want to.
+
+func InternalError(log string) sdkError {
+	return newSDKError(CodeInternalError, log)
+}
+
+func EncodingError(log string) sdkError {
+	return newSDKError(CodeEncodingError, log)
+}
+
+func BadNonce(log string) sdkError {
+	return newSDKError(CodeBadNonce, log)
+}
+
+func Unauthorized(log string) sdkError {
+	return newSDKError(CodeUnauthorized, log)
+}
+
+func InsufficientFunds(log string) sdkError {
+	return newSDKError(CodeInsufficientFunds, log)
+}
+
+func UnknownRequest(log string) sdkError {
+	return newSDKError(CodeUnknownRequest, log)
+}
+
+//----------------------------------------
+
+type ABCIError interface {
+	ABCICode() uint32
+	ABCILog() string
+}
+
+/*
+
+	This struct is intended to be used with pkg/errors.
+
+	Usage:
+
+	```
+		import sdk "github.com/cosmos/cosmos-sdk"
+		import "github.com/pkg/errors"
+
+		var err = <some causal error>
+		if err != nil {
+			err = sdk.InternalError("").WithCause(err)
+			err = errors.Wrap(err, "Captured the stack!")
+			return err
+		}
+	```
+
+	Then, to get the ABCI code/log:
+
+	1. Check if err.(ABCIError)
+	2. Check if err.(causer).Cause().(ABCIError)
+
+*/
+type sdkError struct {
+	code  uint32
+	log   string
+	cause error
+	// TODO stacktrace
+}
+
+func newSDKError(code uint32, log string) sdkError {
+	// TODO capture stacktrace if ENV is set
+	if log == "" {
+		log = codeToDefaultLog(code)
+	}
+	return sdkError{
+		code: code,
+		log:  log,
+	}
+}
+
+func (err sdkError) Error() string {
+	return fmt.Sprintf("SDKError{%d: %s}", err.code, err.log)
+}
+
+// Implements ABCIError
+func (err sdkError) ABCICode() uint32 {
+	return err.code
+}
+
+// Implements ABCIError
+func (err sdkError) ABCILog() string {
+	return err.log
+}
+
+func (err sdkError) Cause() error {
+	return err.cause
+}
+
+func (err sdkError) WithCause(cause error) sdkError {
+	copy := err
+	copy.cause = cause
+	return copy
+}