Merge lp:~jamesh/go-unityscopes/go-1.6-compat into lp:go-unityscopes/v2

[James Henstridge]

Update code to work with Go 1.6's new cgo pointer handling rules:

http://tip.golang.org/cmd/cgo/#hdr-Passing_pointers

Without these changes, it is necessary to run scopes using GODEBUG=cgocheck=0 if they are compiled on Xenial.

The changes make sure we never pass pointers to C that point at memory containing other pointers to Go allocated memory. So rather than passing a pointer to the Go string header to pass a string without copying it, we now pass a pointer to the string data plus the length (packed together in a struct).

[dobey (dobey)]

Why has this been sitting here for six months without review? :(

We need this landed to get go scopes working on xenial for the coming unity8 snap.

review: Approve

=== modified file 'activationresponse.cpp'
--- activationresponse.cpp	2016-02-03 07:17:04 +0000
+++ activationresponse.cpp	2016-04-18 08:45:48 +0000
@@ -9,8 +9,10 @@
 extern "C" {
 #include "_cgo_export.h"
 }
+#include "helpers.h"
 
 using namespace unity::scopes;
+using namespace gounityscopes::internal;
 
 void activation_response_init_status(_ActivationResponse *response, int status) {
     *reinterpret_cast<ActivationResponse*>(response) =
@@ -27,13 +29,11 @@
         ActivationResponse(*reinterpret_cast<Result*>(result));
 }
 
-void activation_response_init_update_preview(_ActivationResponse *response, void *gostring_array, int count, char **error) {
+void activation_response_init_update_preview(_ActivationResponse *response, const StrData widget_list, char **error) {
     try {
-        GoString *widget_data = static_cast<GoString*>(gostring_array);
         PreviewWidgetList widgets;
-        for (int i = 0; i < count; i++) {
-            widgets.push_back(PreviewWidget(std::string(
-                widget_data[i].p, widget_data[i].n)));
+        for (const auto &data : split_strings(widget_list)) {
+            widgets.push_back(PreviewWidget(data));
         }
         *reinterpret_cast<ActivationResponse*>(response) =
             ActivationResponse(widgets);

=== modified file 'activationresponse.go'
--- activationresponse.go	2015-10-20 05:43:00 +0000
+++ activationresponse.go	2016-04-18 08:45:48 +0000
@@ -90,7 +90,7 @@
 			widgetData[i] = string(data)
 		}
 		var errorString *C.char
-		C.activation_response_init_update_preview(responsePtr, unsafe.Pointer(&widgetData[0]), C.int(len(widgetData)), &errorString)
+		C.activation_response_init_update_preview(responsePtr, joinedStrData(widgetData), &errorString)
 		if err := checkError(errorString); err != nil {
 			return err
 		}

=== modified file 'childscope.cpp'
--- childscope.cpp	2015-06-09 15:03:05 +0000
+++ childscope.cpp	2016-04-18 08:45:48 +0000
@@ -11,13 +11,12 @@
 using namespace unity::scopes;
 using namespace gounityscopes::internal;
 
-_ChildScope *new_child_scope(void *id, _ScopeMetadata *metadata, int enabled, void *gostring_array, int count) {
+_ChildScope *new_child_scope(const StrData id, _ScopeMetadata *metadata, int enabled, const StrData keyword_list) {
     ScopeMetadata *api_metadata = reinterpret_cast<ScopeMetadata *>(metadata);
 
-    GoString *keyword_data = static_cast<GoString*>(gostring_array);
     std::set<std::string> keywords;
-    for (int i = 0; i < count; i++) {
-        keywords.emplace(std::string(keyword_data[i].p, keyword_data[i].n));
+    for (auto &k : split_strings(keyword_list)) {
+        keywords.emplace(std::move(k));
     }
 
     return reinterpret_cast<_ChildScope *>(new ChildScope(from_gostring(id), *api_metadata, enabled, keywords));

=== modified file 'childscope.go'
--- childscope.go	2015-05-21 19:22:44 +0000
+++ childscope.go	2016-04-18 08:45:48 +0000
@@ -34,11 +34,10 @@
 	} else {
 		cEnabled = 0
 	}
-	return makeChildScope(C.new_child_scope(unsafe.Pointer(&id),
+	return makeChildScope(C.new_child_scope(strData(id),
 		(*C._ScopeMetadata)(metadata.m),
 		cEnabled,
-		unsafe.Pointer(&keywords[0]),
-		C.int(len(keywords))))
+		joinedStrData(keywords)))
 }
 
 // Id returns the identifier of the child scope

=== modified file 'column_layout.cpp'
--- column_layout.cpp	2015-03-05 14:59:18 +0000
+++ column_layout.cpp	2016-04-18 08:45:48 +0000
@@ -23,16 +23,10 @@
     return reinterpret_cast<_ColumnLayout*>(new ColumnLayout(num_columns));
 }
 
-void column_layout_add_column(_ColumnLayout *layout, void *gostring_array_widgets, int nb_widgets, char **error) {
-    GoString *widget_data = static_cast<GoString*>(gostring_array_widgets);
-
-    std::vector<std::string> api_widgets;
-    // convert to std::string
-    for (auto i = 0; i < nb_widgets; ++i) {
-        api_widgets.push_back(std::string(widget_data[i].p, widget_data[i].n));
-    }
+void column_layout_add_column(_ColumnLayout *layout, const StrData widget_list, char **error) {
+    std::vector<std::string> widgets = split_strings(widget_list);
     try {
-        reinterpret_cast<ColumnLayout*>(layout)->add_column(api_widgets);
+        reinterpret_cast<ColumnLayout*>(layout)->add_column(widgets);
     } catch(unity::LogicException & e) {
         *error = strdup(e.what());
     }

=== modified file 'column_layout.go'
--- column_layout.go	2015-03-23 11:16:52 +0000
+++ column_layout.go	2016-04-18 08:45:48 +0000
@@ -6,7 +6,6 @@
 import (
 	"encoding/json"
 	"runtime"
-	"unsafe"
 )
 
 // ColumnLayout is used represent different representations of a widget.
@@ -41,11 +40,7 @@
 // AddColumn method.
 func (layout *ColumnLayout) AddColumn(widgetIds ...string) error {
 	var errorString *C.char
-	var ptr_columns unsafe.Pointer
-	if len(widgetIds) > 0 {
-		ptr_columns = unsafe.Pointer(&widgetIds[0])
-	}
-	C.column_layout_add_column(layout.c, ptr_columns, C.int(len(widgetIds)), &errorString)
+	C.column_layout_add_column(layout.c, joinedStrData(widgetIds), &errorString)
 
 	return checkError(errorString)
 }

=== modified file 'department.cpp'
--- department.cpp	2015-03-05 14:59:18 +0000
+++ department.cpp	2016-04-18 08:45:48 +0000
@@ -19,17 +19,11 @@
     init_ptr<Department>(dest, dept);
 }
 
-void new_department(void *dept_id, _CannedQuery *query, void *label, SharedPtrData dept, char **error) {
+void new_department(const StrData dept_id, _CannedQuery *query, const StrData label, SharedPtrData dept, char **error) {
     try {
-        Department::UPtr d;
-        if(dept_id) {
-            d = Department::create(from_gostring(dept_id),
-                                    *reinterpret_cast<CannedQuery*>(query),
-                                    from_gostring(label));
-        } else {
-            d = Department::create(*reinterpret_cast<CannedQuery*>(query),
-                                   from_gostring(label));
-        }
+        auto d = Department::create(from_gostring(dept_id),
+                               *reinterpret_cast<CannedQuery*>(query),
+                               from_gostring(label));
         init_ptr<Department>(dept, std::move(d));
     } catch (const std::exception &e) {
         *error = strdup(e.what());
@@ -44,7 +38,7 @@
     get_ptr<Department>(dept)->add_subdepartment(get_ptr<Department>(child));
 }
 
-void department_set_alternate_label(SharedPtrData dept, void *label) {
+void department_set_alternate_label(SharedPtrData dept, const StrData label) {
     get_ptr<Department>(dept)->set_alternate_label(from_gostring(label));
 }
 
@@ -80,10 +74,10 @@
     return ret_data;
 }
 
-void department_set_subdepartments(SharedPtrData dept, SharedPtrData **subdepartments, int nb_subdepartments) {
+void department_set_subdepartments(SharedPtrData dept, SharedPtrData *subdepartments, int nb_subdepartments) {
     DepartmentList api_depts;
     for(auto i = 0; i < nb_subdepartments; i++) {
-        api_depts.push_back(get_ptr<Department>(*subdepartments[i]));
+        api_depts.push_back(get_ptr<Department>(subdepartments[i]));
     }
     get_ptr<Department>(dept)->set_subdepartments(api_depts);
 }

=== modified file 'department.go'
--- department.go	2015-04-07 07:36:43 +0000
+++ department.go	2016-04-18 08:45:48 +0000
@@ -24,7 +24,7 @@
 func NewDepartment(departmentID string, query *CannedQuery, label string) (*Department, error) {
 	dept := makeDepartment()
 	var errorString *C.char
-	C.new_department(unsafe.Pointer(&departmentID), query.q, unsafe.Pointer(&label), &dept.d[0], &errorString)
+	C.new_department(strData(departmentID), query.q, strData(label), &dept.d[0], &errorString)
 
 	if err := checkError(errorString); err != nil {
 		return nil, err
@@ -70,7 +70,7 @@
 // The alternate label only needs to be provided for the current
 // department.
 func (dept *Department) SetAlternateLabel(label string) {
-	C.department_set_alternate_label(&dept.d[0], unsafe.Pointer(&label))
+	C.department_set_alternate_label(&dept.d[0], strData(label))
 }
 
 // AlternateLabel gets the alternate label for this department.
@@ -126,9 +126,17 @@
 
 // SetSubdepartments sets sub-departments of this department.
 func (dept *Department) SetSubdepartments(subdepartments []*Department) {
-	api_depts := make([]*C.SharedPtrData, len(subdepartments))
+	// This technically breaks C++ shared_ptr rules because we are
+	// making a copy of the shared_ptr that doesn't own a
+	// reference.
+	//
+	// However, we know the copy won't be destroyed on the C++
+	// side, and we hold references to the underlying Deparment
+	// objects, preventing them from being cleaned up while the
+	// shared_ptr copies are in scope.
+	api_depts := make([]C.SharedPtrData, len(subdepartments))
 	for i := 0; i < len(subdepartments); i++ {
-		api_depts[i] = &subdepartments[i].d
+		api_depts[i] = subdepartments[i].d
 	}
 	if len(subdepartments) > 0 {
 		C.department_set_subdepartments(&dept.d[0], &api_depts[0], C.int(len(subdepartments)))

=== modified file 'helpers.cpp'
--- helpers.cpp	2015-02-26 10:39:56 +0000
+++ helpers.cpp	2016-04-18 08:45:48 +0000
@@ -10,9 +10,21 @@
 namespace gounityscopes {
 namespace internal {
 
-std::string from_gostring(void *str) {
-    GoString *s = static_cast<GoString*>(str);
-    return std::string(s->p, s->n);
+std::string from_gostring(const StrData str) {
+    return std::string(str.data, str.length);
+}
+
+std::vector<std::string> split_strings(const StrData str) {
+    std::vector<std::string> list;
+    const char *s = str.data;
+    // str contains a sequence of nul-terminated strings concatenated together.
+    for (const char *p = str.data; p != str.data + str.length; ++p) {
+        if (*p == '\0') {
+            list.push_back(s);
+            s = p + 1;
+        }
+    }
+    return list;
 }
 
 void *as_bytes(const std::string &str, int *length) {

=== added file 'helpers.go'
--- helpers.go	1970-01-01 00:00:00 +0000
+++ helpers.go	2016-04-18 08:45:48 +0000
@@ -0,0 +1,49 @@
+package scopes
+
+// #include <stdlib.h>
+// #include "shim.h"
+import "C"
+import (
+	"reflect"
+	"unsafe"
+)
+
+// strData transforms a string to a form that can be passed to cgo
+// without copying data.
+func strData(s string) C.StrData {
+	h := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	return C.StrData{
+		data: (*C.char)(unsafe.Pointer(h.Data)),
+		length: C.long(len(s)),
+	}
+}
+
+// byteData transforms a byte array into the same format strData() produces.
+func byteData(b []byte) C.StrData {
+	if len(b) == 0 {
+		return C.StrData{
+			data: nil,
+			length: 0,
+		}
+	}
+	return C.StrData{
+		data: (*C.char)(unsafe.Pointer(&b[0])),
+		length: C.long(len(b)),
+	}
+}
+
+
+func joinedStrData(a []string) C.StrData {
+	total := 0
+	for _, s := range a {
+		total += len(s) + 1
+	}
+	buf := make([]byte, total)
+	i := 0
+	for _, s := range a {
+		copy(buf[i:i+len(s)], s)
+		buf[i+len(s)] = 0
+		i += len(s) + 1
+	}
+	return byteData(buf)
+}

=== modified file 'helpers.h'
--- helpers.h	2015-02-26 10:39:56 +0000
+++ helpers.h	2016-04-18 08:45:48 +0000
@@ -2,11 +2,15 @@
 #define UNITYSCOPE_HELPERS_H
 
 #include <string>
+#include <vector>
+
+typedef struct StrData StrData;
 
 namespace gounityscopes {
 namespace internal {
 
-std::string from_gostring(void *str);
+std::string from_gostring(const StrData str);
+std::vector<std::string> split_strings(const StrData str);
 void *as_bytes(const std::string &str, int *length);
 
 }

=== modified file 'metadata.cpp'
--- metadata.cpp	2015-05-21 12:21:03 +0000
+++ metadata.cpp	2016-04-18 08:45:48 +0000
@@ -16,7 +16,7 @@
 using namespace gounityscopes::internal;
 
 /* SearchMetadata objects */
-_SearchMetadata *new_search_metadata(int cardinality, void *locale, void *form_factor) {
+_SearchMetadata *new_search_metadata(int cardinality, const StrData locale, const StrData form_factor) {
     return reinterpret_cast<_SearchMetadata*>(new SearchMetadata(cardinality,
                                                                 from_gostring(locale),
                                                                 from_gostring(form_factor)));
@@ -88,12 +88,11 @@
     }
 }
 
-void search_metadata_set_aggregated_keywords(_SearchMetadata *metadata, void *gostring_array, int count, char **error) {
+void search_metadata_set_aggregated_keywords(_SearchMetadata *metadata, const StrData keyword_list, char **error) {
     try {
-        GoString *keyword_data = static_cast<GoString*>(gostring_array);
         std::set<std::string> keywords;
-        for (int i = 0; i < count; i++) {
-            keywords.emplace(std::string(keyword_data[i].p, keyword_data[i].n));
+        for (auto &k : split_strings(keyword_list)) {
+            keywords.emplace(std::move(k));
         }
         reinterpret_cast<SearchMetadata*>(metadata)->set_aggregated_keywords(keywords);
     } catch (const std::exception & e) {
@@ -115,7 +114,7 @@
 
 
 /* ActionMetadata objects */
-_ActionMetadata *new_action_metadata(void *locale, void *form_factor) {
+_ActionMetadata *new_action_metadata(const StrData locale, const StrData form_factor) {
     return reinterpret_cast<_ActionMetadata*>(new ActionMetadata(from_gostring(locale),
                                                                  from_gostring(form_factor)));
 }
@@ -138,7 +137,7 @@
     }
 }
 
-void action_metadata_set_hint(_ActionMetadata *metadata, void *key, char *json_data, int json_data_length, char **error) {
+void action_metadata_set_hint(_ActionMetadata *metadata, const StrData key, char *json_data, int json_data_length, char **error) {
     try {
         Variant value = Variant::deserialize_json(std::string(json_data, json_data_length));
         reinterpret_cast<ActionMetadata*>(metadata)->set_hint(from_gostring(key), value);
@@ -147,7 +146,7 @@
     }
 }
 
-void *action_metadata_get_hint(_ActionMetadata *metadata, void *key, int *data_length, char **error) {
+void *action_metadata_get_hint(_ActionMetadata *metadata, const StrData key, int *data_length, char **error) {
     try {
         ActionMetadata const*api_metadata = reinterpret_cast<ActionMetadata const*>(metadata);
         Variant value = (*api_metadata)[from_gostring(key)];

=== modified file 'metadata.go'
--- metadata.go	2015-05-21 14:58:07 +0000
+++ metadata.go	2016-04-18 08:45:48 +0000
@@ -71,8 +71,8 @@
 // form_factor
 func NewSearchMetadata(cardinality int, locale, form_factor string) *SearchMetadata {
 	return makeSearchMetadata(C.new_search_metadata(C.int(cardinality),
-		unsafe.Pointer(&locale),
-		unsafe.Pointer(&form_factor)))
+		strData(locale),
+		strData(form_factor)))
 }
 
 // Cardinality returns the desired number of results for the search request.
@@ -134,7 +134,7 @@
 
 func (metadata *SearchMetadata) SetAggregatedKeywords(keywords []string) error {
 	var errorString *C.char
-	C.search_metadata_set_aggregated_keywords((*C._SearchMetadata)(metadata.m), unsafe.Pointer(&keywords[0]), C.int(len(keywords)), &errorString)
+	C.search_metadata_set_aggregated_keywords((*C._SearchMetadata)(metadata.m), joinedStrData(keywords), &errorString)
 	return checkError(errorString)
 }
 
@@ -171,8 +171,8 @@
 // NewActionMetadata creates a new ActionMetadata with the given locale and
 // form_factor
 func NewActionMetadata(locale, form_factor string) *ActionMetadata {
-	return makeActionMetadata(C.new_action_metadata(unsafe.Pointer(&locale),
-		unsafe.Pointer(&form_factor)))
+	return makeActionMetadata(C.new_action_metadata(strData(locale),
+		strData(form_factor)))
 }
 
 func makeActionMetadata(m *C._ActionMetadata) *ActionMetadata {
@@ -211,7 +211,7 @@
 		return err
 	}
 	var errorString *C.char
-	C.action_metadata_set_hint((*C._ActionMetadata)(metadata.m), unsafe.Pointer(&key), (*C.char)(unsafe.Pointer(&data[0])), C.int(len(data)), &errorString)
+	C.action_metadata_set_hint((*C._ActionMetadata)(metadata.m), strData(key), (*C.char)(unsafe.Pointer(&data[0])), C.int(len(data)), &errorString)
 	return checkError(errorString)
 }
 
@@ -220,7 +220,7 @@
 func (metadata *ActionMetadata) Hint(key string, value interface{}) error {
 	var dataLength C.int
 	var errorString *C.char
-	scopeData := C.action_metadata_get_hint((*C._ActionMetadata)(metadata.m), unsafe.Pointer(&key), &dataLength, &errorString)
+	scopeData := C.action_metadata_get_hint((*C._ActionMetadata)(metadata.m), strData(key), &dataLength, &errorString)
 	if dataLength > 0 && errorString == nil {
 		defer C.free(scopeData)
 		return json.Unmarshal(C.GoBytes(scopeData, dataLength), value)

=== modified file 'query.cpp'
--- query.cpp	2015-02-28 00:44:27 +0000
+++ query.cpp	2016-04-18 08:45:48 +0000
@@ -15,7 +15,7 @@
     delete reinterpret_cast<CannedQuery*>(query);
 }
 
-_CannedQuery *new_canned_query(void *scope_id, void *query_str, void *department_id) {
+_CannedQuery *new_canned_query(const StrData scope_id, const StrData query_str, const StrData department_id) {
     return reinterpret_cast<_CannedQuery*>(
         new CannedQuery(from_gostring(scope_id),
                         from_gostring(query_str),
@@ -45,11 +45,11 @@
     return strdup(reinterpret_cast<CannedQuery*>(query)->query_string().c_str());
 }
 
-void canned_query_set_department_id(_CannedQuery *query, void *department_id) {
+void canned_query_set_department_id(_CannedQuery *query, const StrData department_id) {
     reinterpret_cast<CannedQuery*>(query)->set_department_id(from_gostring(department_id));
 }
 
-void canned_query_set_query_string(_CannedQuery *query, void *query_str) {
+void canned_query_set_query_string(_CannedQuery *query, const StrData query_str) {
     reinterpret_cast<CannedQuery*>(query)->set_query_string(from_gostring(query_str));
 }
 

=== modified file 'query.go'
--- query.go	2015-02-28 00:44:27 +0000
+++ query.go	2016-04-18 08:45:48 +0000
@@ -32,9 +32,9 @@
 // query string and department ID.
 func NewCannedQuery(scopeID, queryString, departmentID string) *CannedQuery {
 	return makeCannedQuery(C.new_canned_query(
-		unsafe.Pointer(&scopeID),
-		unsafe.Pointer(&queryString),
-		unsafe.Pointer(&departmentID)))
+		strData(scopeID),
+		strData(queryString),
+		strData(departmentID)))
 }
 
 // ScopeID returns the scope ID for this canned query.
@@ -72,12 +72,12 @@
 
 // SetDepartmentID changes the department ID for this canned query.
 func (query *CannedQuery) SetDepartmentID(departmentID string) {
-	C.canned_query_set_department_id(query.q, unsafe.Pointer(&departmentID))
+	C.canned_query_set_department_id(query.q, strData(departmentID))
 }
 
 // SetQueryString changes the query string for this canned query.
 func (query *CannedQuery) SetQueryString(queryString string) {
-	C.canned_query_set_query_string(query.q, unsafe.Pointer(&queryString))
+	C.canned_query_set_query_string(query.q, strData(queryString))
 }
 
 // ToURI formats the canned query as a URI.

=== modified file 'reply.cpp'
--- reply.cpp	2015-03-25 07:46:21 +0000
+++ reply.cpp	2016-04-18 08:45:48 +0000
@@ -28,12 +28,12 @@
     get_ptr<SearchReply>(reply)->finished();
 }
 
-void search_reply_error(SharedPtrData reply, void *err_string) {
+void search_reply_error(SharedPtrData reply, const StrData err_string) {
     get_ptr<SearchReply>(reply)->error(std::make_exception_ptr(
         std::runtime_error(from_gostring(err_string))));
 }
 
-void search_reply_register_category(SharedPtrData reply, void *id, void *title, void *icon, void *cat_template, SharedPtrData category) {
+void search_reply_register_category(SharedPtrData reply, const StrData id, const StrData title, const StrData icon, const StrData cat_template, SharedPtrData category) {
     CategoryRenderer renderer;
     std::string renderer_template = from_gostring(cat_template);
     if (!renderer_template.empty()) {
@@ -55,7 +55,7 @@
     }
 }
 
-void search_reply_push_filters(SharedPtrData reply, void *filters_json, void *filter_state_json, char **error) {
+void search_reply_push_filters(SharedPtrData reply, const StrData filters_json, const StrData filter_state_json, char **error) {
 #if UNITY_SCOPES_VERSION_MAJOR == 0 && (UNITY_SCOPES_VERSION_MINOR < 6 || (UNITY_SCOPES_VERSION_MINOR == 6 && UNITY_SCOPES_VERSION_MICRO < 10))
     std::string errorMessage = "SearchReply.PushFilters() is only available when compiled against libunity-scopes >= 0.6.10";
     *error = strdup(errorMessage.c_str());
@@ -89,18 +89,16 @@
     get_ptr<PreviewReply>(reply)->finished();
 }
 
-void preview_reply_error(SharedPtrData reply, void *err_string) {
+void preview_reply_error(SharedPtrData reply, const StrData err_string) {
     get_ptr<PreviewReply>(reply)->error(std::make_exception_ptr(
         std::runtime_error(from_gostring(err_string))));
 }
 
-void preview_reply_push_widgets(SharedPtrData reply, void *gostring_array, int count, char **error) {
+void preview_reply_push_widgets(SharedPtrData reply, const StrData widget_list, char **error) {
     try {
-        GoString *widget_data = static_cast<GoString*>(gostring_array);
         PreviewWidgetList widgets;
-        for (int i = 0; i < count; i++) {
-            widgets.push_back(PreviewWidget(std::string(
-                widget_data[i].p, widget_data[i].n)));
+        for (const auto &w : split_strings(widget_list)) {
+            widgets.push_back(PreviewWidget(w));
         }
         get_ptr<PreviewReply>(reply)->push(widgets);
     } catch (const std::exception &e) {
@@ -108,7 +106,7 @@
     }
 }
 
-void preview_reply_push_attr(SharedPtrData reply, void *key, void *json_value, char **error) {
+void preview_reply_push_attr(SharedPtrData reply, const StrData key, const StrData json_value, char **error) {
     try {
         Variant value = Variant::deserialize_json(from_gostring(json_value));
         get_ptr<PreviewReply>(reply)->push(from_gostring(key), value);

=== modified file 'reply.go'
--- reply.go	2015-03-25 08:14:19 +0000
+++ reply.go	2016-04-18 08:45:48 +0000
@@ -6,7 +6,6 @@
 import (
 	"encoding/json"
 	"runtime"
-	"unsafe"
 )
 
 // SearchReply is used to send results of search queries to the client.
@@ -41,7 +40,7 @@
 // with an error.
 func (reply *SearchReply) Error(err error) {
 	errString := err.Error()
-	C.search_reply_error(&reply.r[0], unsafe.Pointer(&errString))
+	C.search_reply_error(&reply.r[0], strData(errString))
 }
 
 // RegisterCategory registers a new results category with the client.
@@ -56,7 +55,7 @@
 func (reply *SearchReply) RegisterCategory(id, title, icon, template string) *Category {
 	cat := new(Category)
 	runtime.SetFinalizer(cat, finalizeCategory)
-	C.search_reply_register_category(&reply.r[0], unsafe.Pointer(&id), unsafe.Pointer(&title), unsafe.Pointer(&icon), unsafe.Pointer(&template), &cat.c[0])
+	C.search_reply_register_category(&reply.r[0], strData(id), strData(title), strData(icon), strData(template), &cat.c[0])
 	return cat
 }
 
@@ -95,7 +94,7 @@
 		return err
 	}
 	var errorString *C.char
-	C.search_reply_push_filters(&reply.r[0], unsafe.Pointer(&filtersJson), unsafe.Pointer(&stateJson), &errorString)
+	C.search_reply_push_filters(&reply.r[0], strData(filtersJson), strData(stateJson), &errorString)
 	return checkError(errorString)
 }
 
@@ -131,7 +130,7 @@
 // with an error.
 func (reply *PreviewReply) Error(err error) {
 	errString := err.Error()
-	C.preview_reply_error(&reply.r[0], unsafe.Pointer(&errString))
+	C.preview_reply_error(&reply.r[0], strData(errString))
 }
 
 // PushWidgets sends one or more preview widgets to the client.
@@ -145,7 +144,7 @@
 		widget_data[i] = string(data)
 	}
 	var errorString *C.char
-	C.preview_reply_push_widgets(&reply.r[0], unsafe.Pointer(&widget_data[0]), C.int(len(widget_data)), &errorString)
+	C.preview_reply_push_widgets(&reply.r[0], joinedStrData(widget_data), &errorString)
 	return checkError(errorString)
 }
 
@@ -162,7 +161,7 @@
 	}
 	json_value := string(data)
 	var errorString *C.char
-	C.preview_reply_push_attr(&reply.r[0], unsafe.Pointer(&attr), unsafe.Pointer(&json_value), &errorString)
+	C.preview_reply_push_attr(&reply.r[0], strData(attr), strData(json_value), &errorString)
 	return checkError(errorString)
 }
 

=== modified file 'result.cpp'
--- result.cpp	2015-03-02 05:43:42 +0000
+++ result.cpp	2016-04-18 08:45:48 +0000
@@ -23,7 +23,7 @@
     delete reinterpret_cast<Result*>(res);
 }
 
-void *result_get_attr(_Result *res, void *attr, int *length, char **error) {
+void *result_get_attr(_Result *res, const StrData attr, int *length, char **error) {
     std::string json_data;
     try {
         Variant v = reinterpret_cast<Result*>(res)->value(from_gostring(attr));
@@ -35,7 +35,7 @@
     return as_bytes(json_data, length);
 }
 
-void result_set_attr(_Result *res, void *attr, void *json_value, char **error) {
+void result_set_attr(_Result *res, const StrData attr, const StrData json_value, char **error) {
     try {
         Variant v = Variant::deserialize_json(from_gostring(json_value));
         (*reinterpret_cast<Result*>(res))[from_gostring(attr)] = v;

=== modified file 'result.go'
--- result.go	2015-03-23 11:16:52 +0000
+++ result.go	2016-04-18 08:45:48 +0000
@@ -6,7 +6,6 @@
 import (
 	"encoding/json"
 	"runtime"
-	"unsafe"
 )
 
 // Result represents a result from the scope
@@ -39,7 +38,7 @@
 		length      C.int
 		errorString *C.char
 	)
-	data := C.result_get_attr(res.result, unsafe.Pointer(&attr), &length, &errorString)
+	data := C.result_get_attr(res.result, strData(attr), &length, &errorString)
 	if err := checkError(errorString); err != nil {
 		return err
 	}
@@ -59,7 +58,7 @@
 	stringValue := string(data)
 
 	var errorString *C.char
-	C.result_set_attr(res.result, unsafe.Pointer(&attr), unsafe.Pointer(&stringValue), &errorString)
+	C.result_set_attr(res.result, strData(attr), strData(stringValue), &errorString)
 	return checkError(errorString)
 }
 

=== modified file 'shim.cpp'
--- shim.cpp	2015-05-21 16:26:12 +0000
+++ shim.cpp	2016-04-18 08:45:48 +0000
@@ -14,8 +14,9 @@
 using namespace unity::scopes;
 using namespace gounityscopes::internal;
 
-void run_scope(void *scope_name, void *runtime_config, void *scope_config,
-               void *pointer_to_iface, char **error) {
+void run_scope(const StrData scope_name, const StrData runtime_config,
+               const StrData scope_config, void *pointer_to_iface,
+               char **error) {
     try {
         auto runtime = Runtime::create_scope_runtime(
             from_gostring(scope_name), from_gostring(runtime_config));

=== modified file 'shim.h'
--- shim.h	2015-10-20 05:34:29 +0000
+++ shim.h	2016-04-18 08:45:48 +0000
@@ -11,6 +11,11 @@
 
 typedef uintptr_t SharedPtrData[2];
 
+typedef struct StrData {
+    char *data;
+    long length;
+} StrData;
+
 typedef struct _CannedQuery _CannedQuery;
 typedef struct _Result _Result;
 typedef struct _Result _CategorisedResult;
@@ -25,8 +30,8 @@
 
 typedef struct _ActivationResponse _ActivationResponse;
 
-void run_scope(void *scope_name, void *runtime_config,
-               void *scope_config, void *pointer_to_iface,
+void run_scope(const StrData scope_name, const StrData runtime_config,
+               const StrData scope_config, void *pointer_to_iface,
                char **error);
 
 /* ScopeBase objects */
@@ -38,7 +43,7 @@
 _ChildScope **list_child_scopes(_ScopeBase *scope, int *n_scopes);
 
 /* ChildScope objects */
-_ChildScope *new_child_scope(void *id, _ScopeMetadata *metadata, int enabled, void *gostring_array, int count);
+_ChildScope *new_child_scope(const StrData id, _ScopeMetadata *metadata, int enabled, const StrData keyword_list);
 void destroy_child_scope(_ChildScope *childscope);
 char *child_scope_get_id(_ChildScope *childscope);
 void set_child_scopes_list(void *child_scopes_list, _ChildScope **source_child_scopes, int length);
@@ -48,31 +53,31 @@
 void destroy_search_reply_ptr(SharedPtrData data);
 
 void search_reply_finished(SharedPtrData reply);
-void search_reply_error(SharedPtrData reply, void *err_string);
-void search_reply_register_category(SharedPtrData reply, void *id, void *title, void *icon, void *cat_template, SharedPtrData category);
+void search_reply_error(SharedPtrData reply, const StrData err_string);
+void search_reply_register_category(SharedPtrData reply, const StrData id, const StrData title, const StrData icon, const StrData cat_template, SharedPtrData category);
 void search_reply_register_departments(SharedPtrData reply, SharedPtrData dept);
 void search_reply_push(SharedPtrData reply, _CategorisedResult *result, char **error);
-void search_reply_push_filters(SharedPtrData reply, void *filters_json, void *filter_state_json, char **error);
+void search_reply_push_filters(SharedPtrData reply, const StrData filters_json, const StrData filter_state_json, char **error);
 
 /* PreviewReply objects */
 void init_preview_reply_ptr(SharedPtrData dest, SharedPtrData src);
 void destroy_preview_reply_ptr(SharedPtrData data);
 
 void preview_reply_finished(SharedPtrData reply);
-void preview_reply_error(SharedPtrData reply, void *err_string);
-void preview_reply_push_widgets(SharedPtrData reply, void *gostring_array, int count, char **error);
-void preview_reply_push_attr(SharedPtrData reply, void *key, void *json_value, char **error);
+void preview_reply_error(SharedPtrData reply, const StrData err_string);
+void preview_reply_push_widgets(SharedPtrData reply, const StrData widget_list, char **error);
+void preview_reply_push_attr(SharedPtrData reply, const StrData key, const StrData json_value, char **error);
 void preview_reply_register_layout(SharedPtrData reply, _ColumnLayout **layout, int n_items, char **error);
 
 /* CannedQuery objects */
 void destroy_canned_query(_CannedQuery *query);
-_CannedQuery *new_canned_query(void *scope_id, void *query_str, void *department_id);
+_CannedQuery *new_canned_query(const StrData scope_id, const StrData query_str, const StrData department_id);
 char *canned_query_get_scope_id(_CannedQuery *query);
 char *canned_query_get_department_id(_CannedQuery *query);
 char *canned_query_get_query_string(_CannedQuery *query);
 void *canned_query_get_filter_state(_CannedQuery *query, int *length);
-void canned_query_set_department_id(_CannedQuery *query, void *department_id);
-void canned_query_set_query_string(_CannedQuery *query, void *query_str);
+void canned_query_set_department_id(_CannedQuery *query, const StrData department_id);
+void canned_query_set_query_string(_CannedQuery *query, const StrData query_str);
 char *canned_query_to_uri(_CannedQuery *query);
 
 /* Category objects */
@@ -83,16 +88,16 @@
 void destroy_result(_Result *res);
 
 /* Result objects */
-void *result_get_attr(_Result *res, void *attr, int *length, char **error);
-void result_set_attr(_Result *res, void *attr, void *json_value, char **error);
+void *result_get_attr(_Result *res, const StrData attr, int *length, char **error);
+void result_set_attr(_Result *res, const StrData attr, const StrData json_value, char **error);
 void result_set_intercept_activation(_Result *res);
 
 /* Department objects */
 void init_department_ptr(SharedPtrData dest, SharedPtrData src);
-void new_department(void *deptt_id, _CannedQuery *query, void *label, SharedPtrData dept, char **error);
+void new_department(const StrData deptt_id, _CannedQuery *query, const StrData label, SharedPtrData dept, char **error);
 void destroy_department_ptr(SharedPtrData data);
 void department_add_subdepartment(SharedPtrData dept, SharedPtrData child);
-void department_set_alternate_label(SharedPtrData dept, void *label);
+void department_set_alternate_label(SharedPtrData dept, const StrData label);
 char *department_get_alternate_label(SharedPtrData dept);
 char *department_get_id(SharedPtrData dept);
 char *department_get_label(SharedPtrData dept);
@@ -100,7 +105,7 @@
 int department_has_subdepartments(SharedPtrData dept);
 //void department_get_subdepartments(SharedPtrData dept, SharedPtrData **ret_data);
 SharedPtrData * department_get_subdepartments(SharedPtrData dept, int *n_subdepts);
-void department_set_subdepartments(SharedPtrData dept, SharedPtrData **subdepartments, int nb_subdepartments);
+void department_set_subdepartments(SharedPtrData dept, SharedPtrData *subdepartments, int nb_subdepartments);
 _CannedQuery * department_get_query(SharedPtrData dept);
 
 /* QueryMetadata objects */
@@ -110,22 +115,22 @@
 int query_metadata_get_internet_connectivity(_QueryMetadata *metadata);
 
 /* SearchMetadata objects */
-_SearchMetadata *new_search_metadata(int cardinality, void *locale, void *form_factor);
+_SearchMetadata *new_search_metadata(int cardinality, const StrData locale, const StrData form_factor);
 void destroy_search_metadata(_SearchMetadata *metadata);
 int search_metadata_get_cardinality(_SearchMetadata *metadata);
 void *search_metadata_get_location(_SearchMetadata *metadata, int *length);
 void search_metadata_set_location(_SearchMetadata *metadata, char *json_data, int json_data_length, char **error);
-void search_metadata_set_aggregated_keywords(_SearchMetadata *metadata, void *gostring_array, int count, char **error);
+void search_metadata_set_aggregated_keywords(_SearchMetadata *metadata, const StrData keyword_list, char **error);
 void *search_metadata_get_aggregated_keywords(_SearchMetadata *metadata, int *length);
 int search_metadata_is_aggregated(_SearchMetadata *metadata);
 
 /* ActionMetadata objects */
-_ActionMetadata *new_action_metadata(void *locale, void *form_factor);
+_ActionMetadata *new_action_metadata(const StrData locale, const StrData form_factor);
 void destroy_action_metadata(_ActionMetadata *metadata);
 void *action_metadata_get_scope_data(_ActionMetadata *metadata, int *data_length);
 void action_metadata_set_scope_data(_ActionMetadata *metadata, char *json_data, int json_data_length, char **error);
-void action_metadata_set_hint(_ActionMetadata *metadata, void *key, char *json_data, int json_data_length, char **error);
-void *action_metadata_get_hint(_ActionMetadata *metadata, void *key, int *data_length, char **error);
+void action_metadata_set_hint(_ActionMetadata *metadata, const StrData key, char *json_data, int json_data_length, char **error);
+void *action_metadata_get_hint(_ActionMetadata *metadata, const StrData key, int *data_length, char **error);
 void *action_metadata_get_hints(_ActionMetadata *metadata, int *length);
 
 /* ScopeMetadata objects */
@@ -136,13 +141,13 @@
 void activation_response_init_status(_ActivationResponse *response, int status);
 void activation_response_init_query(_ActivationResponse *response, _CannedQuery *query);
 void activation_response_init_update_result(_ActivationResponse *response, _Result *result);
-void activation_response_init_update_preview(_ActivationResponse *response, void *gostring_array, int count, char **error);
+void activation_response_init_update_preview(_ActivationResponse *response, const StrData widget_list, char **error);
 void activation_response_set_scope_data(_ActivationResponse *response, char *json_data, int json_data_length, char **error);
 
 /* ColumnLayout objects */
 _ColumnLayout *new_column_layout(int num_columns);
 void destroy_column_layout(_ColumnLayout *layout);
-void column_layout_add_column(_ColumnLayout *layout, void *gostring_array_widgets, int nb_widgets, char **error);
+void column_layout_add_column(_ColumnLayout *layout, const StrData widget_list, char **error);
 int column_layout_number_of_columns(_ColumnLayout *layout);
 int column_layout_size(_ColumnLayout *layout);
 void *column_layout_column(_ColumnLayout *layout, int column, int *n_items, char **error);

=== modified file 'unityscope.go'
--- unityscope.go	2015-06-09 15:03:05 +0000
+++ unityscope.go	2016-04-18 08:45:48 +0000
@@ -254,7 +254,7 @@
 	scopeId := base[:len(base)-len(".ini")]
 
 	var errorString *C.char
-	C.run_scope(unsafe.Pointer(&scopeId), unsafe.Pointer(runtimeConfig), unsafe.Pointer(scopeConfig), unsafe.Pointer(&scope), &errorString)
+	C.run_scope(strData(scopeId), strData(*runtimeConfig), strData(*scopeConfig), unsafe.Pointer(&scope), &errorString)
 	return checkError(errorString)
 }