From e8030a95795cb7e18e50c901f92e1b15a726bbc5 Mon Sep 17 00:00:00 2001
From: mappu <mappu04@gmail.com>
Date: Sat, 20 May 2017 15:13:16 +1200
Subject: [PATCH] cgo: change interface to not return already-collected error
 interfaces

---
 main.go           | 38 +++++++++++++++++++++-----------------
 qbolt.h           | 10 ++++------
 qbolt/boltdb.cpp  | 12 ++++++------
 qbolt/interop.cpp |  9 ---------
 qbolt/interop.h   |  2 --
 5 files changed, 31 insertions(+), 40 deletions(-)

diff --git a/main.go b/main.go
index c9a1dfc..1d01aaf 100644
--- a/main.go
+++ b/main.go
@@ -34,24 +34,24 @@ func Recall(f func(a int64) int64) int64 {
 }
 
 //export Bolt_Open
-func Bolt_Open(path string, mode uint32, opts ObjectReference) (ObjectReference, error) {
+func Bolt_Open(path string, mode uint32, opts ObjectReference) (ObjectReference, string) {
 	optsIFC, ok := gms.Get(opts)
 	if !ok {
-		return 0, NullObjectReference
+		return 0, ""
 	}
 
 	ptrBoltOps, ok := optsIFC.(*bolt.Options)
 	if !ok {
-		return 0, NullObjectReference
+		return 0, ""
 	}
 
 	ptrDB, err := bolt.Open(path, os.FileMode(mode), ptrBoltOps)
 	if err != nil {
-		return 0, err
+		return 0, err.Error()
 	}
 
 	dbRef := gms.Put(ptrDB)
-	return dbRef, nil
+	return dbRef, ""
 }
 
 func withBoltDBReference(b ObjectReference, fn func(db *bolt.DB) error) error {
@@ -68,13 +68,8 @@ func withBoltDBReference(b ObjectReference, fn func(db *bolt.DB) error) error {
 	return fn(ptrDB)
 }
 
-//export Error_Error
-func Error_Error(e error) string {
-	return e.Error()
-}
-
 //export Bolt_ListBuckets
-func Bolt_ListBuckets(b ObjectReference, browse []string, withEach func(string)) error {
+func Bolt_ListBuckets(b ObjectReference, browse []string, withEach func(string)) string {
 	if len(browse) == 0 {
 		return Bolt_ListBucketsAtRoot(b, withEach)
 	}
@@ -102,11 +97,16 @@ func Bolt_ListBuckets(b ObjectReference, browse []string, withEach func(string))
 
 		})
 	})
-	return err
+
+	if err != nil {
+		return err.Error()
+	}
+
+	return ""
 }
 
 //export Bolt_ListBucketsAtRoot
-func Bolt_ListBucketsAtRoot(b ObjectReference, withEach func(string)) error {
+func Bolt_ListBucketsAtRoot(b ObjectReference, withEach func(string)) string {
 	err := withBoltDBReference(b, func(db *bolt.DB) error {
 		return db.View(func(tx *bolt.Tx) error {
 
@@ -118,21 +118,25 @@ func Bolt_ListBucketsAtRoot(b ObjectReference, withEach func(string)) error {
 
 		})
 	})
-	return err
+
+	if err != nil {
+		return err.Error()
+	}
+	return ""
 }
 
 //export Bolt_Close
-func Bolt_Close(b ObjectReference) error {
+func Bolt_Close(b ObjectReference) string {
 	err := withBoltDBReference(b, func(db *bolt.DB) error {
 		return db.Close()
 	})
 
 	if err != nil {
-		return err
+		return err.Error()
 	}
 
 	gms.Delete(b)
-	return nil
+	return ""
 }
 
 func main() {
diff --git a/qbolt.h b/qbolt.h
index 8ca0ed9..9a8fdc8 100644
--- a/qbolt.h
+++ b/qbolt.h
@@ -63,18 +63,16 @@ extern GoInt64 Recall(void* p0);
 /* Return type for Bolt_Open */
 struct Bolt_Open_return {
 	GoInt64 r0;
-	GoInterface r1;
+	GoString r1;
 };
 
 extern struct Bolt_Open_return Bolt_Open(GoString p0, GoUint32 p1, GoInt64 p2);
 
-extern GoString Error_Error(GoInterface p0);
+extern GoString Bolt_ListBuckets(GoInt64 p0, GoSlice p1, void* p2);
 
-extern GoInterface Bolt_ListBuckets(GoInt64 p0, GoSlice p1, void* p2);
+extern GoString Bolt_ListBucketsAtRoot(GoInt64 p0, void* p1);
 
-extern GoInterface Bolt_ListBucketsAtRoot(GoInt64 p0, void* p1);
-
-extern GoInterface Bolt_Close(GoInt64 p0);
+extern GoString Bolt_Close(GoInt64 p0);
 
 #ifdef __cplusplus
 }
diff --git a/qbolt/boltdb.cpp b/qbolt/boltdb.cpp
index 1772a70..3bc4a09 100644
--- a/qbolt/boltdb.cpp
+++ b/qbolt/boltdb.cpp
@@ -13,8 +13,8 @@ BoltDB* BoltDB::createFrom(QString filePath, QString &errorOut)
     GoString filePathGS = Interop::toGoString_WeakRef(&filePathBytes);
 
     auto open_ret = Bolt_Open(filePathGS, 0444, opts);
-    if (open_ret.r1.v != nullptr) {
-        errorOut = Interop::GetError(open_ret.r1);
+    if (open_ret.r1.n != 0) {
+        errorOut = QString(open_ret.r1.p);
         return nullptr;
     }
 
@@ -25,9 +25,9 @@ BoltDB* BoltDB::createFrom(QString filePath, QString &errorOut)
 
 BoltDB::~BoltDB()
 {
-    auto err = Bolt_Close(this->gmsDbRef);
-    if (err.v != nullptr) {
-        // Error closing database:
-        // errorOut = Interop::GetError(err);
+    GoString err = Bolt_Close(this->gmsDbRef);
+    if (err.n != 0) {
+        // Error closing database!
+        // Need to display an alert... somewhere
     }
 }
diff --git a/qbolt/interop.cpp b/qbolt/interop.cpp
index 5ecb514..fe8da7c 100644
--- a/qbolt/interop.cpp
+++ b/qbolt/interop.cpp
@@ -5,15 +5,6 @@ Interop::Interop()
 
 }
 
-QString Interop::GetError(GoInterface err) {
-    if (err.v == nullptr) {
-        return ""; // no error
-    }
-
-    GoString gs = Error_Error(err);
-    return QString::fromUtf8(gs.p, gs.n);
-}
-
 GoString Interop::toGoString_WeakRef(QByteArray *qba) {
     return GoString{qba->data(), qba->length()};
 }
diff --git a/qbolt/interop.h b/qbolt/interop.h
index 6278e01..f637fbc 100644
--- a/qbolt/interop.h
+++ b/qbolt/interop.h
@@ -9,8 +9,6 @@ class Interop
 public:
     Interop();
 
-    static QString GetError(GoInterface err);
-
     static GoString toGoString_WeakRef(QByteArray *qba);
 
     static int64_t GetMagic();