further progress

TODO.md

@@ -1,9 +1,10 @@
 # TODO
-- finish verbose mode
 - set core.QCoreApplication_SetApplicationName("App") core.QCoreApplication_SetOrganizationName("Desertbit")
-- ImageProvider
+- slots return values
-- signals & slots
 - docker container
-- call qml slots directly from go
+- properties
+- models
 - dp for pixels
-- document, that slot names must not overlap with QObject names!
+- add catch exception also to free methods.
+- document, that slot names must not overlap with QObject names!
+- call qml slots directly from go?

app.go

@@ -52,13 +52,13 @@ func init() {
 	C.gml_app_init()
 }
 
-// TODO: free
 type App struct {
+	freed    bool
 	threadID int
 
 	app  C.gml_app
 	argc int
-	argv **C.char // TODO: free
+	argv **C.char
 
 	mutex      sync.Mutex
 	ctxPropMap map[string]interface{}
@@ -78,6 +78,9 @@ func NewAppWithArgs(args []string) (a *App, err error) {
 	// Ensure the thread is locked within this context of app creation.
 	runtime.LockOSThread()
 
+	apiErr := errorPool.Get()
+	defer errorPool.Put(apiErr)
+
 	a = &App{
 		threadID:   utils.GetThreadID(),
 		argc:       len(args),
@@ -85,10 +88,31 @@ func NewAppWithArgs(args []string) (a *App, err error) {
 		ctxPropMap: make(map[string]interface{}),
 		imgProvMap: make(map[string]*ImageProvider),
 	}
-	a.app = C.gml_app_new(C.int(a.argc), a.argv)
+
+	a.app = C.gml_app_new(C.int(a.argc), a.argv, apiErr.err)
+	if a.app == nil {
+		err = apiErr.Err("failed to create new app")
+		return
+	}
+
+	// Always free the C value.
+	runtime.SetFinalizer(a, freeApp)
 	return
 }
 
+func freeApp(a *App) {
+	if a.freed {
+		return
+	}
+	a.freed = true
+	C.gml_app_free(a.app)
+	freeCharArray(a.argv, a.argc)
+}
+
+func (a *App) Free() {
+	freeApp(a)
+}
+
 // RunMain runs the function on the applications main thread.
 func (a *App) RunMain(f func()) {
 	// Check if already running on the main thread.
@@ -106,11 +130,10 @@ func (a *App) RunMain(f func()) {
 	ptr := pointer.Save(cb)
 	defer pointer.Unref(ptr)
 
-	// TODO:
+	ret := C.gml_app_run_main(a.app, ptr)
-	_ = C.gml_app_run_main(a.app, ptr)
+	if ret != 0 {
-	/*if error {
 		return
-	}*/
+	}
 
 	<-doneChan
 }
@@ -121,31 +144,39 @@ func (a *App) Load(url string) error {
 	urlC := C.CString(url)
 	defer C.free(unsafe.Pointer(urlC))
 
-	// TODO:
+	apiErr := errorPool.Get()
-	_ = int(C.gml_app_load(a.app, urlC))
+	defer errorPool.Put(apiErr)
+
+	ret := C.gml_app_load(a.app, urlC, apiErr.err)
+	if ret != 0 {
+		return apiErr.Err("failed to load url")
+	}
 	return nil
 }
 
-// Load the QML given in data.
+// LoadData loads the QML given in data.
 // Hint: Must be called within main thread.
 func (a *App) LoadData(data string) error {
 	dataC := C.CString(data)
 	defer C.free(unsafe.Pointer(dataC))
 
-	// TODO:
+	apiErr := errorPool.Get()
-	_ = int(C.gml_app_load_data(a.app, dataC))
+	defer errorPool.Put(apiErr)
+
+	ret := C.gml_app_load_data(a.app, dataC, apiErr.err)
+	if ret != 0 {
+		return apiErr.Err("failed to load data")
+	}
 	return nil
 }
 
 // AddImportPath adds the given import path to the app engine.
 // Hint: Must be called within main thread.
-func (a *App) AddImportPath(path string) error {
+func (a *App) AddImportPath(path string) {
 	pathC := C.CString(path)
 	defer C.free(unsafe.Pointer(pathC))
 
-	// TODO:
+	C.gml_app_add_import_path(a.app, pathC)
-	_ = int(C.gml_app_add_import_path(a.app, pathC))
-	return nil
 }
 
 // AddImageProvider adds the image provider to the app engine for the given id.
@@ -153,9 +184,16 @@ func (a *App) AddImageProvider(id string, ip *ImageProvider) error {
 	idC := C.CString(id)
 	defer C.free(unsafe.Pointer(idC))
 
+	apiErr := errorPool.Get()
+	defer errorPool.Put(apiErr)
+
+	var ret C.int
 	a.RunMain(func() {
-		_ = int(C.gml_app_add_imageprovider(a.app, idC, ip.ip))
+		ret = C.gml_app_add_imageprovider(a.app, idC, ip.ip, apiErr.err)
 	})
+	if ret != 0 {
+		return apiErr.Err("failed to add image provider")
+	}
 
 	// Add to map to ensure it gets not garbage collected.
 	// It is in use by the C++ context;
@@ -169,16 +207,23 @@ func (a *App) AddImageProvider(id string, ip *ImageProvider) error {
 // Exec executes the application and returns the exit code.
 // This method is blocking.
 // Hint: Must be called within main thread.
-func (a *App) Exec() int {
+func (a *App) Exec() (retCode int, err error) {
-	return int(C.gml_app_exec(a.app))
+	apiErr := errorPool.Get()
+	defer errorPool.Put(apiErr)
+
+	retCode = int(C.gml_app_exec(a.app, apiErr.err))
+	if retCode != 0 {
+		err = apiErr.Err("app execution failed")
+		return
+	}
+	return
 }
 
 // Quit the application.
-func (a *App) Quit() (retCode int) {
+func (a *App) Quit() {
 	a.RunMain(func() {
-		retCode = int(C.gml_app_quit(a.app))
+		C.gml_app_quit(a.app)
 	})
-	return
 }
 
 func (a *App) SetContextProperty(name string, v interface{}) (err error) {
@@ -195,10 +240,16 @@ func (a *App) SetContextProperty(name string, v interface{}) (err error) {
 	nameC := C.CString(name)
 	defer C.free(unsafe.Pointer(nameC))
 
+	apiErr := errorPool.Get()
+	defer errorPool.Put(apiErr)
+
+	var ret C.int
 	a.RunMain(func() {
-		// TODO:
+		ret = C.gml_app_set_root_context_property(a.app, nameC, obj.cObject(), apiErr.err)
-		_ = int(C.gml_app_set_root_context_property(a.app, nameC, obj.cObject()))
 	})
+	if ret != 0 {
+		return apiErr.Err("failed to set context property")
+	}
 
 	// Add to map to ensure it gets not garbage collected.
 	// It is in use by the C++ context;

error.go

@@ -0,0 +1,68 @@
+/*
+ * GML - Go QML
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Roland Singer <roland.singer[at]desertbit.com>
+ * Copyright (c) 2019 Sebastian Borchers <sebastian[at]desertbit.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package gml
+
+// #include <gml.h>
+import "C"
+import "errors"
+
+type apiError struct {
+	err C.gml_error
+}
+
+func newAPIError() *apiError {
+	return &apiError{
+		err: C.gml_error_new(),
+	}
+}
+
+func (e *apiError) Free() {
+	C.gml_error_free(e.err)
+}
+
+func (e *apiError) String() string {
+	return C.GoString(C.gml_error_get_msg(e.err))
+}
+
+func (e *apiError) Reset() {
+	C.gml_error_reset(e.err)
+}
+
+func (e *apiError) Err(prefix ...string) error {
+	s := e.String()
+	if len(prefix) > 0 {
+		if len(s) == 0 {
+			s = prefix[0]
+		} else {
+			s = prefix[0] + ": " + s
+		}
+	} else if len(s) == 0 {
+		s = "unknown error"
+	}
+	return errors.New(s)
+}

errors.go

@@ -0,0 +1,83 @@
+/*
+ * GML - Go QML
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Roland Singer <roland.singer[at]desertbit.com>
+ * Copyright (c) 2019 Sebastian Borchers <sebastian[at]desertbit.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package gml
+
+const (
+	errorPoolSize = 50
+)
+
+var (
+	errorPool = newAPIErrorPool(errorPoolSize)
+)
+
+type apiErrorPool struct {
+	pool chan *apiError
+}
+
+func newAPIErrorPool(poolSize int) *apiErrorPool {
+	return &apiErrorPool{
+		pool: make(chan *apiError, poolSize),
+	}
+}
+
+// Get an error from the pool.
+// Allocates new memory if the pool is empty.
+func (p *apiErrorPool) Get() (e *apiError) {
+	select {
+	case e = <-p.pool:
+	default:
+		e = newAPIError()
+	}
+	return
+}
+
+// Put an error back to the pool.
+func (p *apiErrorPool) Put(e *apiError) {
+	// Reset the error message.
+	e.Reset()
+
+	select {
+	case p.pool <- e:
+	default:
+		// Just let it go. The pool is full.
+		e.Free()
+	}
+}
+
+// Reset empties the pool.
+func (p *apiErrorPool) Reset() {
+	var e *apiError
+	for {
+		select {
+		case e = <-p.pool:
+			e.Free()
+		default:
+			return
+		}
+	}
+}

gml.go

@@ -32,3 +32,17 @@ package gml
 // #cgo LDFLAGS: -lstdc++
 // #include <gml.h>
 import "C"
+import (
+	"fmt"
+	"os"
+)
+
+// Exec executes the app, prints errors and exits
+// the application with the specific exit code.
+func Exec(a *App) {
+	ret, err := a.Exec()
+	if err != nil {
+		fmt.Println(err)
+	}
+	os.Exit(ret)
+}

image.go

@@ -78,8 +78,17 @@ func (img *Image) Free() {
 	freeImage(img)
 }
 
-func (img *Image) LoadFromData(data []byte) (err error) {
+func (img *Image) LoadFromData(data []byte) error {
-	// TODO:
+	if len(data) == 0 {
-	_ = C.gml_image_load_from_data(img.img, (*C.char)(unsafe.Pointer(&data[0])), C.int(len(data)))
+		return fmt.Errorf("empty data")
-	return
+	}
+
+	apiErr := errorPool.Get()
+	defer errorPool.Put(apiErr)
+
+	ret := C.gml_image_load_from_data(img.img, (*C.char)(unsafe.Pointer(&data[0])), C.int(len(data)), apiErr.err)
+	if ret != 0 {
+		return apiErr.Err("failed to load from data")
+	}
+	return nil
 }

internal/binding/headers/gml.h

@@ -31,6 +31,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 
+#include "gml_error.h"
 #include "gml_app.h"
 #include "gml_image.h"
 #include "gml_object.h"

internal/binding/headers/gml_app.h

@@ -32,6 +32,7 @@
 extern "C" {
 #endif
 
+#include "gml_error.h"
 #include "gml_object.h"
 #include "gml_imageprovider.h"
 
@@ -40,18 +41,18 @@ typedef void* gml_app;
 typedef void (*gml_app_run_main_cb_t)(void* go_ptr);
 void gml_app_run_main_cb_register(gml_app_run_main_cb_t cb);
 
-gml_app gml_app_new (int argv, char** argc);
+gml_app gml_app_new (int argv, char** argc, gml_error err);
 void    gml_app_free(gml_app app);
-int     gml_app_exec(gml_app app);
+int     gml_app_exec(gml_app app, gml_error err);
-int     gml_app_quit(gml_app app);
+void    gml_app_quit(gml_app app);
 int     gml_app_run_main(gml_app app, void* go_ptr);
 
-int     gml_app_load     (gml_app app, const char* url);
+int     gml_app_load     (gml_app app, const char* url, gml_error err);
-int     gml_app_load_data(gml_app app, const char* data);
+int     gml_app_load_data(gml_app app, const char* data, gml_error err);
-int     gml_app_add_import_path(gml_app app, const char* path);
+void    gml_app_add_import_path(gml_app app, const char* path);
-int     gml_app_add_imageprovider(gml_app app, const char* id, gml_imageprovider ip);
+int     gml_app_add_imageprovider(gml_app app, const char* id, gml_imageprovider ip, gml_error err);
 
-int     gml_app_set_root_context_property(gml_app app, const char* name, gml_object obj);
+int     gml_app_set_root_context_property(gml_app app, const char* name, gml_object obj, gml_error err);
 
 #ifdef __cplusplus
 }

internal/binding/headers/gml_error.h

@@ -32,7 +32,12 @@
 extern "C" {
 #endif
 
-typedef void* gml_object;
+typedef void* gml_error;
+
+gml_error   gml_error_new();
+void        gml_error_free   (gml_error err);
+void        gml_error_reset  (gml_error err);
+const char* gml_error_get_msg(gml_error err);
 
 #ifdef __cplusplus
 }

internal/binding/headers/gml_image.h

@@ -36,7 +36,7 @@ typedef void* gml_image;
 
 gml_image gml_image_new();
 void      gml_image_free(gml_image img);
-int       gml_image_load_from_data(gml_image img, char* data, int size);
+int       gml_image_load_from_data(gml_image img, char* data, int size, gml_error err);
 
 #ifdef __cplusplus
 }

internal/binding/sources/gml_app.cpp

@@ -41,17 +41,17 @@ void gml_app_run_main_cb_register(gml_app_run_main_cb_t cb) {
     gml_app_run_main_cb = cb;
 }
 
-gml_app gml_app_new(int argc, char** argv) {
+gml_app gml_app_new(int argc, char** argv, gml_error err) {
     try {
         GmlApp* a = new GmlApp(argc, argv);
         return (void*)a;
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_set_msg(err, e.what());
         return NULL;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_set_catched_exception_msg(err);
         return NULL;
     }
 }
@@ -65,34 +65,31 @@ void gml_app_free(gml_app app) {
     app = NULL;
 }
 
-int gml_app_exec(gml_app app) {
+int gml_app_exec(gml_app app, gml_error err) {
     try {
         GmlApp* a = (GmlApp*)app;
         return a->app.exec();
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_set_msg(err, e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_set_catched_exception_msg(err);
-        return -1; // TODO:
+        return -1;
     }
 }
 
-int gml_app_quit(gml_app app) {
+void gml_app_quit(gml_app app) {
     try {
         GmlApp* a = (GmlApp*)app;
         a->app.quit();
-        return 0; // TODO:
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_log_exception(e.what());
-        return -1; // TODO:
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_log_exception();
-        return -1; // TODO:
     }
 }
 
@@ -100,97 +97,94 @@ int gml_app_run_main(gml_app app, void* go_ptr) {
     try {
         GmlApp* a = (GmlApp*)app;
         emit a->requestRunMain(go_ptr);
-        return 0; // TODO:
+        return 0;
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_log_exception(e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_log_exception();
-        return -1; // TODO:
+        return -1;
     }
 }
 
-int gml_app_load(gml_app app, const char* url) {
+int gml_app_load(gml_app app, const char* url, gml_error err) {
     try {
         GmlApp* a = (GmlApp*)app;
         a->engine.load(QUrl(url));
-        return 0; // TODO:
+        return 0;
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_set_msg(err, e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_set_catched_exception_msg(err);
-        return -1; // TODO:
+        return -1;
     }
 }
 
-int gml_app_load_data(gml_app app, const char* data) {
+int gml_app_load_data(gml_app app, const char* data, gml_error err) {
     try {
         GmlApp* a = (GmlApp*)app;
         a->engine.loadData(data);
-        return 0; // TODO:
+        return 0;
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_set_msg(err, e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_set_catched_exception_msg(err);
-        return -1; // TODO:
+        return -1;
     }
 }
 
-int gml_app_add_import_path(gml_app app, const char* path) {
+void gml_app_add_import_path(gml_app app, const char* path) {
     try {
         GmlApp* a = (GmlApp*)app;
         a->engine.addImportPath(path);
-        return 0; // TODO:
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_log_exception(e.what());
-        return -1; // TODO:
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_log_exception();
-        return -1; // TODO:
     }
 }
 
-int gml_app_add_imageprovider(gml_app app, const char* id, gml_imageprovider ip) {
+int gml_app_add_imageprovider(gml_app app, const char* id, gml_imageprovider ip, gml_error err) {
     try {
         GmlApp* a = (GmlApp*)app;
         GmlImageProvider* gip = (GmlImageProvider*)ip;
         a->engine.addImageProvider(id, gip);
-        return 0; // TODO:
+        return 0; 
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_set_msg(err, e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_set_catched_exception_msg(err);
-        return -1; // TODO:
+        return -1;
     }
 }
 
-int gml_app_set_root_context_property(gml_app app, const char* name, gml_object obj) {
+int gml_app_set_root_context_property(gml_app app, const char* name, gml_object obj, gml_error err) {
     try {
         GmlApp* a  = (GmlApp*)app;
         QObject* o = (QObject*)obj;
         a->engine.rootContext()->setContextProperty(name, o);
-        return 0; // TODO:
+        return 0;
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_set_msg(err, e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_set_catched_exception_msg(err);
-        return -1; // TODO:
+        return -1;
     }
 }
 

internal/binding/sources/gml_app.h

@@ -29,6 +29,7 @@
 #define GML_APP_H
 
 #include "gml_includes.h"
+#include "gml_error.h"
 #include "gml_imageprovider.h"
 
 class GmlApp : public QObject

internal/binding/sources/gml_error.cpp

@@ -0,0 +1,105 @@
+/*
+ * GML - Go QML
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Roland Singer <roland.singer[at]desertbit.com>
+ * Copyright (c) 2019 Sebastian Borchers <sebastian[at]desertbit.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "gml_error.h"
+
+//#############//
+//### C API ###//
+//#############//
+
+gml_error gml_error_new() {
+    try {
+        GmlError* gerr = new GmlError();
+        return (void*)gerr;
+    }
+    catch (std::exception& e) {
+        gml_error_log_exception("new gml_error: " + string(e.what()));
+        return NULL;
+    }
+    catch (...) {
+        gml_error_log_exception("new gml_error");
+        return NULL;
+    }
+}
+
+void gml_error_free(gml_error err) {
+    if (err == NULL) {
+        return;
+    }
+    GmlError* gerr = (GmlError*)err;
+    delete gerr;
+    err = NULL;
+}
+
+void gml_error_reset(gml_error err) {
+    try {
+        GmlError* gerr = (GmlError*)err;
+        gerr->msg = "";
+    }
+    catch (std::exception& e) {
+        gml_error_log_exception("reset error message: " + string(e.what()));
+    }
+    catch (...) {
+        gml_error_log_exception("reset error message");
+    }
+}
+
+const char* gml_error_get_msg(gml_error err) {
+    try {
+        GmlError* gerr = (GmlError*)err;
+        return gerr->msg.c_str();
+    }
+    catch (std::exception& e) {
+        gml_error_log_exception("get error message: " + string(e.what()));
+        return NULL;
+    }
+    catch (...) {
+        gml_error_log_exception("get error message");
+        return NULL;
+    }
+}
+
+//################//
+//### Internal ###//
+//################//
+
+void gml_error_set_msg(gml_error err, const std::string& msg) {
+    GmlError* gerr = (GmlError*)err;
+    gerr->msg = msg;
+}
+
+void gml_error_set_catched_exception_msg(gml_error err) {
+    gml_error_set_msg(err, "catched unknown exception");
+}
+
+void gml_error_log_exception(const string& msg) {
+    if (msg == "") {
+        cerr << "gml: catched unknown exception" << endl;
+    } else {
+        cerr << "gml: catched exception: " << msg << endl;
+    }
+}

internal/binding/sources/gml_error.h

@@ -25,13 +25,17 @@
  * SOFTWARE.
  */
 
-#ifndef GML_APP_H
+#ifndef GML_ERROR_H
-#define GML_APP_H
+#define GML_ERROR_H
 
 #include "gml_includes.h"
 
-struct GmlError struct {
+struct GmlError {
     string msg;
 };
 
+void gml_error_set_msg(gml_error err, const string& msg);
+void gml_error_set_catched_exception_msg(gml_error err);
+void gml_error_log_exception(const string& msg = "");
+
 #endif

internal/binding/sources/gml_image.cpp

@@ -26,6 +26,7 @@
  */
 
 #include "gml_includes.h"
+#include "gml_error.h"
 
 //#############//
 //### C API ###//
@@ -37,11 +38,11 @@ gml_image gml_image_new() {
         return (void*)qImg;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception(e.what());
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception();
         return NULL;
     }
 }
@@ -55,18 +56,18 @@ void gml_image_free(gml_image img) {
     img = NULL;
 }
 
-int gml_image_load_from_data(gml_image img, char* data, int size) {
+int gml_image_load_from_data(gml_image img, char* data, int size, gml_error err) {
     try {
         QImage* qImg = (QImage*)img;
         qImg->loadFromData((const unsigned char*)(data), size);
-        return 0; // TODO:
+        return 0;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_set_msg(err, e.what());
-        return -1; // TODO:
+        return -1;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+         gml_error_set_catched_exception_msg(err);
-        return -1; // TODO:
+        return -1;
     }
 }

internal/binding/sources/gml_imageprovider.cpp

@@ -26,6 +26,7 @@
  */
 
 #include "gml_imageprovider.h"
+#include "gml_error.h"
 
 //########################//
 //### Static Variables ###//
@@ -55,11 +56,11 @@ gml_imageprovider gml_imageprovider_new(
         return (void*)gip;
     }
     catch (std::exception& e) {
-        //api_error_set_msg(err, e.what()); TODO:
+        gml_error_log_exception(e.what());
         return NULL;
     }
     catch (...) {
-        //api_error_set_unknown_msg(err); TODO:
+        gml_error_log_exception();
         return NULL;
     }
 }
@@ -79,10 +80,10 @@ void gml_image_response_emit_finished(gml_image_response img_resp, char* error_s
         gimg_resp->finalize(QString(error_string));
     }
     catch (std::exception& e) {
-        cerr << "gml: catched image response exception: emit finished: " << e.what() << endl;
+        gml_error_log_exception("image response: emit finished: " + string(e.what()));
     }
     catch (...) {
-        cerr << "gml: catched image response exception: emit finished: " << endl;
+        gml_error_log_exception("image response: emit finished");
     }
 }
 
@@ -112,10 +113,10 @@ GmlAsyncImageResponse::GmlAsyncImageResponse(
         );
     }
     catch (std::exception& e) {
-        cerr << "gml: catched GmlAsyncImageResponse exception: " << e.what() << endl;
+        gml_error_log_exception("image async response: request: " + string(e.what()));
     }
     catch (...) {
-        cerr << "gml: catched GmlAsyncImageResponse exception: " << endl;
+        gml_error_log_exception("image async response: request");
     }
 }
 
@@ -133,7 +134,6 @@ void GmlAsyncImageResponse::finalize(const QString& errorString) {
         errorStr = errorString;
     } else if (!requestedSize.isNull() && requestedSize.isValid()) {
         // Resize the image to the requested size
-        cout << requestedSize.width() << ", " << requestedSize.height() << endl;
         img = img.scaled(requestedSize, Qt::IgnoreAspectRatio, transformMode);
     }
 

internal/binding/sources/gml_includes.h

@@ -32,6 +32,7 @@
 
 #include <stdlib.h>
 #include <iostream>
+#include <string>
 
 #include <QObject>
 #include <QUrl>
@@ -45,6 +46,7 @@
 #include <QQuickAsyncImageProvider>
 #include <QQuickImageResponse>
 
+using std::string;
 using std::cout;
 using std::cerr;
 using std::endl;

internal/binding/sources/gml_variant.cpp

@@ -26,6 +26,7 @@
  */
 
 #include "gml_includes.h"
+#include "gml_error.h"
 
 //#############//
 //### C API ###//
@@ -46,11 +47,11 @@ gml_variant gml_variant_new() {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -61,11 +62,11 @@ gml_variant gml_variant_new_from_bool(u_int8_t b) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -76,11 +77,11 @@ gml_variant gml_variant_new_from_float(float f) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -91,11 +92,11 @@ gml_variant gml_variant_new_from_double(double d) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -106,11 +107,11 @@ gml_variant gml_variant_new_from_int(int i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -121,11 +122,11 @@ gml_variant gml_variant_new_from_int8(int8_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -136,11 +137,11 @@ gml_variant gml_variant_new_from_uint8(u_int8_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -151,11 +152,11 @@ gml_variant gml_variant_new_from_int16(int16_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -166,11 +167,11 @@ gml_variant gml_variant_new_from_uint16(u_int16_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -181,11 +182,11 @@ gml_variant gml_variant_new_from_int32(int32_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -196,11 +197,11 @@ gml_variant gml_variant_new_from_uint32(u_int32_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -211,11 +212,11 @@ gml_variant gml_variant_new_from_int64(int64_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -226,11 +227,11 @@ gml_variant gml_variant_new_from_uint64(u_int64_t i) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -241,11 +242,11 @@ gml_variant gml_variant_new_from_qchar(int32_t r) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -256,11 +257,11 @@ gml_variant gml_variant_new_from_string(char* s) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }
@@ -271,11 +272,11 @@ gml_variant gml_variant_new_from_bytes(char* b, int size) {
         return (void*)v;
     }
     catch (std::exception& e) {
-        cerr << "gml: catched variant exception: " << e.what() << endl;
+        gml_error_log_exception("variant: " + string(e.what()));
         return NULL;
     }
     catch (...) {
-        cerr << "gml: catched variant exception" << endl;
+        gml_error_log_exception("variant");
         return NULL;
     }
 }

internal/build/qtproject.go

@@ -32,7 +32,7 @@ import (
 	"text/template"
 )
 
-var qtProTmpl = template.Must(template.New("t").Funcs(tmplFuncMap).Parse(qtProData))
+var qtProTmpl = template.Must(template.New("t").Parse(qtProData))
 
 func prepareQtProject(ctx *Context) (err error) {
 	// Create or open the config file.

internal/build/resources.go

@@ -34,7 +34,7 @@ import (
 	"text/template"
 )
 
-var qmlResTmpl = template.Must(template.New("t").Funcs(tmplFuncMap).Parse(qmlResData))
+var qmlResTmpl = template.Must(template.New("t").Parse(qmlResData))
 
 func prepareResources(ctx *Context) (err error) {
 	// Create the resources file.

samples/hello_world/main.go

@@ -29,7 +29,6 @@ package main
 
 import (
 	"log"
-	"os"
 
 	"github.com/desertbit/gml"
 )
@@ -45,7 +44,7 @@ func main() {
 		log.Fatalln(err)
 	}
 
-	os.Exit(app.Exec())
+	gml.Exec(app)
 }
 
 const qmlData = `

samples/signals_slots/main.go

@@ -30,7 +30,6 @@ package main
 import (
 	"io/ioutil"
 	"log"
-	"os"
 
 	"github.com/desertbit/gml"
 	_ "github.com/desertbit/gml/samples/signals_slots/testy"
@@ -82,5 +81,5 @@ func main() {
 		log.Fatalln(err)
 	}
 
-	os.Exit(app.Exec())
+	gml.Exec(app)
 }