cleaned Go support and added memory leak fix

README_GO.rst

@@ -1,16 +1,15 @@
 Install
 -------
 
-To install, you'll need Swig (tested with Swig 3.0.6 on OS X), and then just::
+To install, you'll need Swig (tested with Swig 4.2.1 on Ubuntu 24.04), and then just::
 
   swig -go -intgosize 64 -cgo -c++ src/annoygomodule.i
-  mkdir -p $GOPATH/src/annoyindex
-  cp src/annoygomodule_wrap.cxx src/annoyindex.go src/annoygomodule.h src/annoylib.h src/kissrandom.h test/annoy_test.go $GOPATH/src/annoyindex
-  cd $GOPATH/src/annoyindex
-  go mod init annoyindex
-  go get -t ...
+  mkdir -p $(go env GOPATH)/src/annoy
+  cp src/annoygomodule_wrap.cxx src/annoy.go src/annoygomodule.h src/annoylib.h src/kissrandom.h test/annoy_test.go $(go env GOPATH)/src/annoy
+  cd $(go env GOPATH)/src/annoy
+  go mod init github.com/spotify/annoy
+  go mod tidy
   go test
-  go build
 
 Background
 ----------
@@ -25,14 +24,15 @@ Go code example
   package main
 
   import (
-         "annoyindex"
          "fmt"
          "math/rand"
+
+         "github.com/spotify/annoy"
   )
 
   func main() {
        f := 40
-       t := annoyindex.NewAnnoyIndexAngular(f)
+       t := annoy.NewAnnoyIndexAngular(f)
        for i := 0; i < 1000; i++ {
        	 item := make([]float32, 0, f)
        	 for x:= 0; x < f; x++ {
@@ -43,14 +43,15 @@ Go code example
        t.Build(10)
        t.Save("test.ann")
 
-       annoyindex.DeleteAnnoyIndexAngular(t)
+       annoy.DeleteAnnoyIndexAngular(t)
 
-       t = annoyindex.NewAnnoyIndexAngular(f)
+       t = annoy.NewAnnoyIndexAngular(f)
        t.Load("test.ann")
 
-       var result []int
-       t.GetNnsByItem(0, 1000, -1, &result)
-       fmt.Printf("%v\n", result)
+       result := annoyindex.NewAnnoyVectorInt()
+       defer result.Free()
+       t.GetNnsByItem(0, 1000, -1, result)
+       fmt.Printf("%v\n", result.ToSlice())
 
   }
 
@@ -68,6 +69,6 @@ A simple test is supplied in test/annoy_test.go.
 Discuss
 -------
 
-There might be some memory leaks. See [this issue](https://github.com/swig/swig/issues/2292).
+Memroy leak in the previous versions has been fixed thanks to https://github.com/swig/swig/issues/2292. (memory leak fix is implemented in https://github.com/Rikanishu/annoy-go)
 
 Go glue written by Taneli Leppä (@rosmo). You can contact me via email (see https://github.com/rosmo).

src/annoygomodule.h

@@ -5,6 +5,73 @@ using namespace Annoy;
 
 namespace GoAnnoy {
 
+
+class AnnoyVectorFloat {
+    protected:
+        float *ptr;
+        int len;
+
+    public:
+      ~AnnoyVectorFloat() {
+        free(ptr);
+      };
+      float* ArrayPtr() {
+        return ptr;
+      };
+      int Len() {
+        return len;
+      };
+      float Get(int i) {
+        if (i >= len) {
+            return 0.0;
+        }
+        return ptr[i];
+      };
+      void fill_from_vector(vector<float>* v) {
+            if (ptr != NULL) {
+               free(ptr);
+            }
+            ptr = (float*) malloc(v->size() * sizeof(float));
+            for (int i = 0; i < v->size(); i++) {
+                ptr[i] = (float)(*v)[i];
+            }
+            len = v->size();
+      };
+};
+
+class AnnoyVectorInt {
+    protected:
+        int32_t *ptr;
+        int len;
+
+    public:
+      ~AnnoyVectorInt() {
+        free(ptr);
+      };
+      int32_t* ArrayPtr() {
+        return ptr;
+      };
+      int Len() {
+        return len;
+      };
+      int32_t Get(int i) {
+        if (i >= len) {
+            return 0.0;
+        }
+        return ptr[i];
+      };
+      void fill_from_vector(vector<int32_t>* v) {
+            if (ptr != NULL) {
+                free(ptr);
+            }
+            ptr = (int32_t*) malloc(v->size() * sizeof(int32_t));
+            for (int i = 0; i < v->size(); i++) {
+                ptr[i] = (int32_t)(*v)[i];
+            }
+            len = v->size();
+      };
+};
+
 class AnnoyIndex {
  protected:
   ::AnnoyIndexInterface<int32_t, float> *ptr;
@@ -39,17 +106,43 @@ class AnnoyIndex {
   float getDistance(int i, int j) {
     return ptr->get_distance(i, j);
   };
-  void getNnsByItem(int item, int n, int search_k, vector<int32_t>* result, vector<float>* distances) {
+  void getNnsByItem(int item, int n, int search_k, AnnoyVectorInt* out_result, AnnoyVectorFloat* out_distances) {
+    vector<int32_t>* result = new vector<int32_t>();
+    vector<float>* distances = new vector<float>();
+
     ptr->get_nns_by_item(item, n, search_k, result, distances);
-  };
-  void getNnsByVector(const float* w, int n, int search_k, vector<int32_t>* result, vector<float>* distances) {
+
+    out_result->fill_from_vector(result);
+    out_distances->fill_from_vector(distances);
+    delete result;
+    delete distances;
+  };
+  void getNnsByVector(const float* w, int n, int search_k, AnnoyVectorInt* out_result, AnnoyVectorFloat* out_distances) {
+    vector<int32_t>* result = new vector<int32_t>();
+    vector<float>* distances = new vector<float>();
+
     ptr->get_nns_by_vector(w, n, search_k, result, distances);
+
+    out_result->fill_from_vector(result);
+    out_distances->fill_from_vector(distances);
+    delete result;
+    delete distances;
   };
-  void getNnsByItem(int item, int n, int search_k, vector<int32_t>* result) {
+  void getNnsByItem(int item, int n, int search_k, AnnoyVectorInt* out_result) {
+    vector<int32_t>* result = new vector<int32_t>();
+
     ptr->get_nns_by_item(item, n, search_k, result, NULL);
+
+    out_result->fill_from_vector(result);
+    delete result;
   };
-  void getNnsByVector(const float* w, int n, int search_k, vector<int32_t>* result) {
+  void getNnsByVector(const float* w, int n, int search_k, AnnoyVectorInt* out_result) {
+    vector<int32_t>* result = new vector<int32_t>();
+
     ptr->get_nns_by_vector(w, n, search_k, result, NULL);
+
+    out_result->fill_from_vector(result);
+    delete result;
   };
 
   int getNItems() {
@@ -58,9 +151,11 @@ class AnnoyIndex {
   void verbose(bool v) {
     ptr->verbose(v);
   };
-  void getItem(int item, vector<float> *v) {
-    v->resize(this->f);
-    ptr->get_item(item, &v->front());
+  void getItem(int item, AnnoyVectorFloat *v) {
+    vector<float>* r = new vector<float>();
+    r->resize(this->f);
+    ptr->get_item(item, &r->front());
+    v->fill_from_vector(r);
   };
   bool onDiskBuild(const char* filename) {
     return ptr->on_disk_build(filename);

src/annoygomodule.i

@@ -1,4 +1,4 @@
-%module annoyindex
+%module annoy
 
 namespace Annoy {}
 
@@ -9,6 +9,7 @@ namespace Annoy {}
 
 // const float *
 %typemap(gotype) (const float *)  "[]float32"
+%typemap(gotype) (int32_t)  "int32"
 
 %typemap(in) (const float *)
 %{
@@ -21,76 +22,125 @@ namespace Annoy {}
     $1 = &w[0];
 %}
 
-// vector<int32_t> *
-%typemap(gotype) (vector<int32_t> *)  "*[]int"
 
-%typemap(in) (vector<int32_t> *)
+%typemap(gotype) (const char *) "string"
+
+%typemap(in) (const char *)
 %{
-  $1 = new vector<int32_t>();
+  $1 = (char *)calloc((((_gostring_)$input).n + 1), sizeof(char));
+  strncpy($1, (((_gostring_)$input).p), ((_gostring_)$input).n);
 %}
 
-%typemap(freearg) (vector<int32_t> *)
+%typemap(freearg) (const char *)
 %{
-  delete $1;
+  free($1);
 %}
 
-%typemap(argout) (vector<int32_t> *)
-%{
-  {
-    $input->len = $1->size();
-    $input->cap = $1->size();
-    $input->array = malloc($input->len * sizeof(intgo));
-    for (int i = 0; i < $1->size(); i++) {
-        ((intgo *)$input->array)[i] = (intgo)(*$1)[i];
+
+%ignore fill_from_vector;
+%rename(X_RawAnnoyVectorInt) AnnoyVectorInt;
+%rename(X_RawAnnoyVectorFloat) AnnoyVectorFloat;
+
+%insert(go_wrapper) %{
+
+type AnnoyVectorInt interface {
+  X_RawAnnoyVectorInt
+  ToSlice() []int32
+  Copy(in *[]int32)
+  InnerArray() []int32
+  Free()
+}
+
+func NewAnnoyVectorInt() AnnoyVectorInt {
+    vec := NewX_RawAnnoyVectorInt()
+    return vec.(SwigcptrX_RawAnnoyVectorInt)
+}
+
+func (p SwigcptrX_RawAnnoyVectorInt) ToSlice() []int32 {
+    var out []int32
+    p.Copy(&out)
+    return out
+}
+
+func (p SwigcptrX_RawAnnoyVectorInt) Copy(in *[]int32)  {
+    out := *in
+    inner := p.InnerArray()
+    if cap(out) >= len(inner) {
+        if len(out) != len(inner) {
+          out = out[:len(inner)]
+        }
+    } else {
+        out = make([]int32, len(inner))
     }
-  }
-%}
 
+    copy(out, inner)
+    *in = out
+}
 
-// vector<float> *
-%typemap(gotype) (vector<float> *)  "*[]float32"
+func (p SwigcptrX_RawAnnoyVectorInt) Free() {
+    DeleteX_RawAnnoyVectorInt(p)
+}
 
-%typemap(in) (vector<float> *)
-%{
-  $1 = new vector<float>();
-%}
+func (p SwigcptrX_RawAnnoyVectorInt) InnerArray() []int32 {
+	length := p.Len()
+    ptr := unsafe.Pointer(p.ArrayPtr())
+	return ((*[1 << 30]int32)(ptr))[:length:length]
+}
 
-%typemap(freearg) (vector<float> *)
-%{
-  delete $1;
 %}
 
-%typemap(argout) (vector<float> *)
-%{
-  {
-    $input->len = $1->size();
-    $input->cap = $1->size();
-    $input->array = malloc($input->len * sizeof(float));
-    for (int i = 0; i < $1->size(); i++) {
-        ((float *)$input->array)[i] = (float)(*$1)[i];
+%insert(go_wrapper) %{
+
+type AnnoyVectorFloat interface {
+  X_RawAnnoyVectorFloat
+  ToSlice() []float32
+  Copy(in *[]float32)
+  InnerArray() []float32
+  Free()
+}
+
+func NewAnnoyVectorFloat() AnnoyVectorFloat {
+    vec := NewX_RawAnnoyVectorFloat()
+    return vec.(SwigcptrX_RawAnnoyVectorFloat)
+}
+
+func (p SwigcptrX_RawAnnoyVectorFloat) ToSlice() []float32 {
+    var out []float32
+    p.Copy(&out)
+    return out
+}
+
+func (p SwigcptrX_RawAnnoyVectorFloat) Copy(in *[]float32)  {
+    out := *in
+    inner := p.InnerArray()
+    if cap(out) >= len(inner) {
+        if len(out) != len(inner) {
+          out = out[:len(inner)]
+        }
+    } else {
+        out = make([]float32, len(inner))
     }
-  }
-%}
 
+    copy(out, inner)
+    *in = out
+}
 
-%typemap(gotype) (const char *) "string"
+func (p SwigcptrX_RawAnnoyVectorFloat) Free() {
+    DeleteX_RawAnnoyVectorFloat(p)
+}
 
-%typemap(in) (const char *)
-%{
-  $1 = (char *)calloc((((_gostring_)$input).n + 1), sizeof(char));
-  strncpy($1, (((_gostring_)$input).p), ((_gostring_)$input).n);
-%}
+func (p SwigcptrX_RawAnnoyVectorFloat) InnerArray() []float32 {
+    length := p.Len()
+    ptr := unsafe.Pointer(p.ArrayPtr())
+    return ((*[1 << 30]float32)(ptr))[:length:length]
+}
 
-%typemap(freearg) (const char *)
-%{
-  free($1);
 %}
 
-
 /* Let's just grab the original header file here */
 %include "annoygomodule.h"
 
 %feature("notabstract") GoAnnoyIndexAngular;
 %feature("notabstract") GoAnnoyIndexEuclidean;
 %feature("notabstract") GoAnnoyIndexManhattan;
-%feature("notabstract") GoAnnoyIndexDotProduct;
+%feature("notabstract") GoAnnoyIndexDotProduct;