finish GstTagList, GstToc, setters, and add auto go type conversion for functions taking gvalues

gst/c_util.go

@@ -4,6 +4,8 @@ package gst
 import "C"
 
 import (
+	"fmt"
+	"time"
 	"unsafe"
 )
 
@@ -20,6 +22,37 @@ func gboolean(b bool) C.gboolean {
 	return C.gboolean(0)
 }
 
+// gdateToTime converts a GDate to a time object.
+func gdateToTime(gdate *C.GDate) time.Time {
+	tm := time.Time{}
+	tm.AddDate(int(C.g_date_get_year(gdate)), int(C.g_date_get_month(gdate)), int(C.g_date_get_day(gdate)))
+	return tm
+}
+
+// gstDateTimeToTime converts a GstDateTime to a time object. If the datetime object could not be parsed,
+// an empty time object is returned.
+func gstDateTimeToTime(gstdatetime *C.GstDateTime) time.Time {
+	dateStr := fmt.Sprintf(
+		"%s %s %d:%d:%d %s %d",
+		time.Weekday(C.gst_date_time_get_day(gstdatetime)).String(),
+		time.Month(C.gst_date_time_get_month(gstdatetime)).String(),
+		int(C.gst_date_time_get_hour(gstdatetime)),
+		int(C.gst_date_time_get_minute(gstdatetime)),
+		int(C.gst_date_time_get_second(gstdatetime)),
+		formatOffset(C.gst_date_time_get_time_zone_offset(gstdatetime)),
+		int(C.gst_date_time_get_year(gstdatetime)),
+	)
+	tm, _ := time.Parse("Mon Jan 2 15:04:05 -0700 2006", dateStr)
+	return tm
+}
+
+func formatOffset(offset C.gfloat) string {
+	if offset < 0 {
+		return fmt.Sprintf("-0%d00", int(offset))
+	}
+	return fmt.Sprintf("+0%d00", int(offset))
+}
+
 // goStrings returns a string slice for an array of size argc starting at the address argv.
 func goStrings(argc C.int, argv **C.gchar) []string {
 	length := int(argc)

gst/cgo_exports.go

@@ -13,6 +13,15 @@ import (
 	gopointer "github.com/mattn/go-pointer"
 )
 
+//export goTagForEachFunc
+func goTagForEachFunc(tagList *C.GstTagList, tag *C.gchar, userData C.gpointer) {
+	cbIface := gopointer.Restore(unsafe.Pointer(userData))
+	cbFunc := cbIface.(TagListForEachFunc)
+	cbFunc(wrapTagList(tagList), Tag(C.GoString(tag)))
+}
+
+// func goTagMergeFunc(dest, src *C.GValue) {}
+
 //export goBufferListForEachCb
 func goBufferListForEachCb(buf **C.GstBuffer, idx C.guint, userData C.gpointer) C.gboolean {
 	cbIface := gopointer.Restore(unsafe.Pointer(userData))

gst/gst.go.h

@@ -35,6 +35,7 @@ inline GstSample *            toGstSample            (void *p) { return (GST_SAM
 inline GstStreamCollection *  toGstStreamCollection  (void *p) { return (GST_STREAM_COLLECTION_CAST(p)); }
 inline GstStream *            toGstStream            (void *p) { return (GST_STREAM_CAST(p)); }
 inline GstStructure *         toGstStructure         (void *p) { return (GST_STRUCTURE(p)); }
+inline GstTagList   *         toGstTagList           (void *p) { return (GST_TAG_LIST(p)); }
 inline GstURIHandler *        toGstURIHandler        (void *p) { return (GST_URI_HANDLER(p)); }
 inline GstUri *               toGstURI               (void *p) { return (GST_URI(p)); }
 
@@ -126,6 +127,11 @@ inline GstToc *         makeTocWritable        (GstToc * toc)           { return
 inline GstToc *         tocRef                 (GstToc * toc)           { return gst_toc_ref(toc); }
 inline void             tocUnref               (GstToc * toc)           { gst_toc_unref(toc); }
 
+/* TagList utilities */
+
+inline gboolean         tagListIsWritable     (GstTagList * tagList)   { return gst_tag_list_is_writable(tagList); }
+inline GstTagList *     makeTagListWritable   (GstTagList * tagList)   { return gst_tag_list_make_writable(tagList); }
+
 /* Object Utilities */
 
 inline GObjectClass *  getGObjectClass         (void * p)                               { return (G_OBJECT_GET_CLASS(p)); }

gst/gst_caps.go

@@ -392,12 +392,17 @@ func (c *Caps) SetFeaturesSimple(features *CapsFeatures) {
 }
 
 // SetValue sets the given field on all structures of caps to the given value. This is a convenience
-// function for calling SetValue on all structures of caps.
-func (c *Caps) SetValue(field string, val *glib.Value) {
+// function for calling SetValue on all structures of caps. If the value cannot be coerced to a C type,
+// then nothing will happen.
+func (c *Caps) SetValue(field string, val interface{}) {
+	gVal, err := glib.GValue(val)
+	if err != nil {
+		return
+	}
 	C.gst_caps_set_value(
 		c.Instance(),
 		(*C.gchar)(unsafe.Pointer(C.CString(field))),
-		(*C.GValue)(val.GetPointer()),
+		(*C.GValue)(gVal.Native()),
 	)
 }
 

gst/gst_message_constructors.go

@@ -288,17 +288,22 @@ func NewProgressMessage(src interface{}, progressType ProgressType, code, text s
 	return wrapMessage(C.gst_message_new_progress(srcObj, C.GstProgressType(progressType), cCode, cText))
 }
 
-// NewPropertyNotifyMessage creates a new message notifying an object's properties have changed.
-func NewPropertyNotifyMessage(src interface{}, propName string, val *glib.Value) *Message {
+// NewPropertyNotifyMessage creates a new message notifying an object's properties have changed. If the
+// source OR the value cannot be coereced to C types, the function will return nil.
+func NewPropertyNotifyMessage(src interface{}, propName string, val interface{}) *Message {
 	srcObj := getMessageSourceObj(src)
 	if srcObj == nil {
 		return nil
 	}
+	gVal, err := glib.GValue(val)
+	if err != nil {
+		return nil
+	}
 	cName := (*C.gchar)(unsafe.Pointer(C.CString(propName)))
 	return wrapMessage(C.gst_message_new_property_notify(
 		srcObj,
 		cName,
-		(*C.GValue)(val.GetPointer()),
+		(*C.GValue)(gVal.Native()),
 	))
 }
 

gst/gst_structure.go

@@ -87,7 +87,7 @@ func (s *Structure) SetValue(key string, value interface{}) error {
 	}
 	cKey := C.CString(key)
 	defer C.free(unsafe.Pointer(cKey))
-	C.gst_structure_set_value(s.Instance(), cKey, (*C.GValue)(gVal.GetPointer()))
+	C.gst_structure_set_value(s.Instance(), cKey, (*C.GValue)(unsafe.Pointer(gVal.GValue)))
 	return nil
 }
 

gst/gst_tag_list.go

@@ -1,9 +1,25 @@
 package gst
 
-// #include "gst.go.h"
+/*
+#include "gst.go.h"
+
+extern void goTagForEachFunc (const GstTagList * tagList, const gchar * tag, gpointer user_data);
+
+void cgoTagForEachFunc (const GstTagList * tagList, const gchar * tag, gpointer user_data)
+{
+	goTagForEachFunc(tagList, tag, user_data);
+}
+
+*/
 import "C"
 
-import "unsafe"
+import (
+	"time"
+	"unsafe"
+
+	"github.com/gotk3/gotk3/glib"
+	gopointer "github.com/mattn/go-pointer"
+)
 
 // TagList is a go wrapper around a GstTagList. For now, until the rest of the methods are
 // implemnented, this struct is primarily used for retrieving serialized copies of the tags.
@@ -11,8 +27,30 @@ type TagList struct {
 	ptr *C.GstTagList
 }
 
+// NewEmptyTagList returns a new empty tag list.
+//
+//   tagList := gst.NewEmptyTagList()
+//   fmt.Println(tagList.IsEmpty())
+//   // true
+//
+func NewEmptyTagList() *TagList {
+	return wrapTagList(C.gst_tag_list_new_empty())
+}
+
+// NewTagListFromString creates a new tag list from the given string. This is the same format produced
+// by the stringer interface on the TagList.
+func NewTagListFromString(tags string) *TagList {
+	ctags := C.CString(tags)
+	defer C.free(unsafe.Pointer(ctags))
+	tagList := C.gst_tag_list_new_from_string((*C.gchar)(unsafe.Pointer(ctags)))
+	if tagList == nil {
+		return nil
+	}
+	return wrapTagList(tagList)
+}
+
 // Instance returns the underlying GstTagList instance.
-func (t *TagList) Instance() *C.GstTagList { return t.ptr }
+func (t *TagList) Instance() *C.GstTagList { return C.toGstTagList(unsafe.Pointer(t.ptr)) }
 
 // String implements a stringer on the TagList and serializes it to a string.
 func (t *TagList) String() string { return C.GoString(C.gst_tag_list_to_string(t.Instance())) }
@@ -24,17 +62,522 @@ func (t *TagList) Ref() *TagList { return wrapTagList(C.gst_tag_list_ref(t.Insta
 // is destroyed.
 func (t *TagList) Unref() { C.gst_tag_list_unref(t.Instance()) }
 
-// Size returns the number of key/value pairs in ths TagList
-func (t *TagList) Size() int { return int(C.gst_tag_list_n_tags(t.Instance())) }
+// AddValue adds a value to a given tag using the given merge mode. If the value provided
+// cannot be coerced to a GValue, nothing will happen.
+//
+//   tagList := gst.NewEmptyTagList()
+//   tagList.AddValue(gst.TagMergeAppend, gst.TagAlbum, "MyNewAlbum")
+//   myAlbum, _ := tagList.GetString(gst.TagAlbum)
+//   fmt.Println(myAlbum)
+//   // MyNewAlbum
+//
+func (t *TagList) AddValue(mergeMode TagMergeMode, tag Tag, value interface{}) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	gVal, err := glib.GValue(value)
+	if err != nil {
+		return
+	}
+	C.gst_tag_list_add_value(
+		t.Instance(),
+		C.GstTagMergeMode(mergeMode),
+		(*C.gchar)(ctag),
+		(*C.GValue)(gVal.Native()),
+	)
+}
+
+// AddValues can be used to add multiple values to a tag with the given merge mode.
+// Values that cannot be coerced to C types will be ignored.
+func (t *TagList) AddValues(mergeMode TagMergeMode, tag Tag, vals ...interface{}) {
+	for _, val := range vals {
+		t.AddValue(mergeMode, tag, val)
+	}
+}
+
+// Copy creates a new TagList as a copy of the old taglist. The new taglist will have a refcount of 1,
+// owned by the caller, and will be writable as a result.
+//
+// Note that this function is the semantic equivalent of a Ref followed by a MakeWritable. If you only want
+// to hold on to a reference to the data, you should use Ref.
+//
+// When you are finished with the taglist, call Unref on it.
+func (t *TagList) Copy() *TagList { return wrapTagList(C.gst_tag_list_copy(t.Instance())) }
+
+// TagListForEachFunc is a function that will be called in ForEach. The function may not modify the tag list.
+type TagListForEachFunc func(tagList *TagList, tag Tag)
+
+// ForEach calls the given function for each tag inside the tag list. Note that if there is no tag,
+// the function won't be called at all.
+//
+//   tagList := gst.NewEmptyTagList()
+//
+//   tagList.AddValue(gst.TagMergeAppend, gst.TagAlbumArtist, "tinyzimmer")
+//   tagList.AddValue(gst.TagMergeAppend, gst.TagAlbum, "GstreamerInGo")
+//
+//   tagList.ForEach(func(_ *gst.TagList, tag gst.Tag) {
+//       val, _ := tagList.GetString(tag)
+//       fmt.Println(tag, ":", val)
+//   })
+//
+//   // album-artist : tinyzimmer
+//   // album : GstreamerInGo
+//
+func (t *TagList) ForEach(f TagListForEachFunc) {
+	ptr := gopointer.Save(f)
+	defer gopointer.Unref(ptr)
+	C.gst_tag_list_foreach(
+		t.Instance(),
+		C.GstTagForeachFunc(C.cgoTagForEachFunc),
+		(C.gpointer)(ptr),
+	)
+}
+
+// GetBool returns the boolean value at the given tag key. If multiple values are associated with the tag they
+// are merged.
+func (t *TagList) GetBool(tag Tag) (value, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gboolean
+	gok := C.gst_tag_list_get_boolean(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return gobool(gout), gobool(gok)
+}
+
+// GetBoolIndex retrieves the bool at the given index in the tag key.
+func (t *TagList) GetBoolIndex(tag Tag, idx uint) (value, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gboolean
+	gok := C.gst_tag_list_get_boolean_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	return gobool(gout), gobool(gok)
+}
+
+// GetDate returns the date stored at the given tag key. If there are multiple values, the first one
+// is returned.
+func (t *TagList) GetDate(tag Tag) (value time.Time, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.GDate
+	gok := C.gst_tag_list_get_date(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	if gobool(gok) {
+		defer C.g_date_free(gout)
+		return gdateToTime(gout), true
+	}
+	return time.Time{}, false
+}
+
+// GetDateIndex returns the date stored at the given index in tag key.
+func (t *TagList) GetDateIndex(tag Tag, idx uint) (value time.Time, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.GDate
+	gok := C.gst_tag_list_get_date_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	if gobool(gok) {
+		defer C.g_date_free(gout)
+		return gdateToTime(gout), true
+	}
+	return time.Time{}, false
+}
+
+// GetDateTime returns the date and time stored at the given tag key. If there are multiple values, the first one
+// is returned.
+func (t *TagList) GetDateTime(tag Tag) (value time.Time, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.GstDateTime
+	gok := C.gst_tag_list_get_date_time(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	if gobool(gok) {
+		defer C.gst_date_time_unref(gout)
+		return gstDateTimeToTime(gout), true
+	}
+	return time.Time{}, false
+}
+
+// GetDateTimeIndex returns the date and time stored at the given tag key at the given index.
+func (t *TagList) GetDateTimeIndex(tag Tag, idx uint) (value time.Time, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.GstDateTime
+	gok := C.gst_tag_list_get_date_time_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	if gobool(gok) {
+		defer C.gst_date_time_unref(gout)
+		return gstDateTimeToTime(gout), true
+	}
+	return time.Time{}, false
+}
+
+// GetFloat64 returns the float at the given tag key, merging multiple values into one if multiple values
+// are associated with the tag. This is the equivalent of a C double stored in the tag.
+func (t *TagList) GetFloat64(tag Tag) (value float64, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gdouble
+	gok := C.gst_tag_list_get_double(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return float64(gout), gobool(gok)
+}
+
+// GetFloat64Index returns the float at the index of the given tag key.
+func (t *TagList) GetFloat64Index(tag Tag, idx uint) (value float64, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gdouble
+	gok := C.gst_tag_list_get_double_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.uint(idx),
+		&gout,
+	)
+	return float64(gout), gobool(gok)
+}
+
+// GetFloat32 returns the float at the given tag key, merging multiple values into one if multiple values
+// are associated with the tag.
+func (t *TagList) GetFloat32(tag Tag) (value float32, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gfloat
+	gok := C.gst_tag_list_get_float(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return float32(gout), gobool(gok)
+}
+
+// GetFloat32Index returns the float at the index of the given tag key.
+func (t *TagList) GetFloat32Index(tag Tag, idx uint) (value float32, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gfloat
+	gok := C.gst_tag_list_get_float_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.uint(idx),
+		&gout,
+	)
+	return float32(gout), gobool(gok)
+}
+
+// GetInt32 returns the integer at the given tag key, merging multiple values into one if multiple values
+// are associated with the tag.
+func (t *TagList) GetInt32(tag Tag) (value int32, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gint
+	gok := C.gst_tag_list_get_int(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return int32(gout), gobool(gok)
+}
+
+// GetInt32Index returns the integer at the index of the given tag key.
+func (t *TagList) GetInt32Index(tag Tag, idx uint) (value int32, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gint
+	gok := C.gst_tag_list_get_int_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.uint(idx),
+		&gout,
+	)
+	return int32(gout), gobool(gok)
+}
+
+// GetInt64 returns the integer at the given tag key, merging multiple values into one if multiple values
+// are associated with the tag.
+func (t *TagList) GetInt64(tag Tag) (value int64, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gint64
+	gok := C.gst_tag_list_get_int64(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return int64(gout), gobool(gok)
+}
+
+// GetInt64Index returns the integer at the index of the given tag key.
+func (t *TagList) GetInt64Index(tag Tag, idx uint) (value int64, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gint64
+	gok := C.gst_tag_list_get_int64_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.uint(idx),
+		&gout,
+	)
+	return int64(gout), gobool(gok)
+}
+
+// GetPointer returns the C pointer stored at the given tag key, merging values if there are multiple.
+func (t *TagList) GetPointer(tag Tag) (value unsafe.Pointer, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gpointer
+	gok := C.gst_tag_list_get_pointer(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return unsafe.Pointer(gout), gobool(gok)
+}
+
+// GetPointerIndex returns the C pointer stored at the given tag key index.
+func (t *TagList) GetPointerIndex(tag Tag, idx uint) (value unsafe.Pointer, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.gpointer
+	gok := C.gst_tag_list_get_pointer_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	return unsafe.Pointer(gout), gobool(gok)
+}
+
+// GetSample copies the first sample for the given tag in the taglist. Free the sample with Unref when it
+// is no longer needed.
+func (t *TagList) GetSample(tag Tag) (value *Sample, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.GstSample
+	gok := C.gst_tag_list_get_sample(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	if gobool(gok) {
+		return wrapSample(gout), true
+	}
+	return nil, false
+}
+
+// GetSampleIndex copies the sample for the given index in tag in the taglist. Free the sample with Unref
+// when it is no longer needed.
+func (t *TagList) GetSampleIndex(tag Tag, idx uint) (value *Sample, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.GstSample
+	gok := C.gst_tag_list_get_sample_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	if gobool(gok) {
+		return wrapSample(gout), true
+	}
+	return nil, false
+}
+
+// GetString returns the string for the given tag, possibly merging multiple values into one.
+func (t *TagList) GetString(tag Tag) (value string, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.gchar
+	gok := C.gst_tag_list_get_string(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	defer C.g_free((C.gpointer)(unsafe.Pointer(gout)))
+	return C.GoString(gout), gobool(gok)
+}
+
+// GetStringIndex returns the string for the given index in tag.
+func (t *TagList) GetStringIndex(tag Tag, idx uint) (value string, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.gchar
+	gok := C.gst_tag_list_get_string_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	defer C.g_free((C.gpointer)(unsafe.Pointer(gout)))
+	return C.GoString(gout), gobool(gok)
+}
+
+// GetUint32 returns the unsigned integer at the given tag key, merging multiple values into one if multiple values
+// are associated with the tag.
+func (t *TagList) GetUint32(tag Tag) (value uint32, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.guint
+	gok := C.gst_tag_list_get_uint(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return uint32(gout), gobool(gok)
+}
+
+// GetUint32Index returns the unsigned integer at the index of the given tag key.
+func (t *TagList) GetUint32Index(tag Tag, idx uint) (value uint32, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.guint
+	gok := C.gst_tag_list_get_uint_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.uint(idx),
+		&gout,
+	)
+	return uint32(gout), gobool(gok)
+}
+
+// GetUint64 returns the unsigned integer at the given tag key, merging multiple values into one if multiple values
+// are associated with the tag.
+func (t *TagList) GetUint64(tag Tag) (value uint64, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.guint64
+	gok := C.gst_tag_list_get_uint64(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		&gout,
+	)
+	return uint64(gout), gobool(gok)
+}
+
+// GetUint64Index returns the unsigned integer at the index of the given tag key.
+func (t *TagList) GetUint64Index(tag Tag, idx uint) (value uint64, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout C.guint64
+	gok := C.gst_tag_list_get_uint64_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.uint(idx),
+		&gout,
+	)
+	return uint64(gout), gobool(gok)
+}
+
+// GetValueIndex retrieves the GValue at the given index in tag, or nil if none exists.
+// Note that this function can also return nil if the stored value cannot be cleanly coerced
+// to a go type. It is safer to use the other functions provided when you know the expected
+// return type.
+func (t *TagList) GetValueIndex(tag Tag, idx uint) interface{} {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	gval := C.gst_tag_list_get_value_index(t.Instance(), (*C.gchar)(unsafe.Pointer(ctag)), C.guint(idx))
+	if gval == nil {
+		return nil
+	}
+	val := glib.ValueFromNative(unsafe.Pointer(gval))
+	iface, _ := val.GoValue()
+	return iface
+}
+
+// GetScope returns the scope for this TagList.
+func (t *TagList) GetScope() TagScope { return TagScope(C.gst_tag_list_get_scope(t.Instance())) }
+
+// GetTagSize returns the number of tag values at the given tag key.
+func (t *TagList) GetTagSize(tagKey string) int {
+	cStr := C.CString(tagKey)
+	defer C.free(unsafe.Pointer(cStr))
+	return int(C.gst_tag_list_get_tag_size(t.Instance(), (*C.gchar)(cStr)))
+}
+
+// Insert inserts the tags from the provided list using the given merge mode.
+func (t *TagList) Insert(tagList *TagList, mergeMode TagMergeMode) {
+	C.gst_tag_list_insert(t.Instance(), tagList.Instance(), C.GstTagMergeMode(mergeMode))
+}
+
+// IsEmpty returns true if this tag list is empty.
+func (t *TagList) IsEmpty() bool { return gobool(C.gst_tag_list_is_empty(t.Instance())) }
+
+// IsEqual checks if the two tag lists are equal.
+func (t *TagList) IsEqual(tagList *TagList) bool {
+	return gobool(C.gst_tag_list_is_equal(t.Instance(), tagList.Instance()))
+}
+
+// IsWritable returns true if this TagList is writable.
+func (t *TagList) IsWritable() bool { return gobool(C.tagListIsWritable(t.Instance())) }
+
+// MakeWritable will return a writable copy of the tag list if it is not already so.
+func (t *TagList) MakeWritable() *TagList {
+	return wrapTagList(C.makeTagListWritable(t.Instance()))
+}
+
+// Merge merges the two tag lists with the given mode.
+func (t *TagList) Merge(tagList *TagList, mergeMode TagMergeMode) *TagList {
+	return wrapTagList(C.gst_tag_list_merge(
+		t.Instance(),
+		tagList.Instance(),
+		C.GstTagMergeMode(mergeMode),
+	))
+}
+
+// NumTags returns the number of key/value pairs in ths TagList
+func (t *TagList) NumTags() int { return int(C.gst_tag_list_n_tags(t.Instance())) }
 
 // TagNameAt returns the tag name at the given index.
 func (t *TagList) TagNameAt(idx int) string {
 	return C.GoString(C.gst_tag_list_nth_tag_name(t.Instance(), C.guint(idx)))
 }
 
-// NumValuesAt returns the number of tag values at the given tag key.
-func (t *TagList) NumValuesAt(tagKey string) int {
-	cStr := C.CString(tagKey)
-	defer C.free(unsafe.Pointer(cStr))
-	return int(C.gst_tag_list_get_tag_size(t.Instance(), (*C.gchar)(cStr)))
+// PeekStringIndex peeks at the value that is at the given index for the given tag in the given list.
+func (t *TagList) PeekStringIndex(tag Tag, idx uint) (value string, ok bool) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	var gout *C.gchar
+	gok := C.gst_tag_list_peek_string_index(
+		t.Instance(),
+		(*C.gchar)(unsafe.Pointer(ctag)),
+		C.guint(idx),
+		&gout,
+	)
+	defer C.g_free((C.gpointer)(unsafe.Pointer(gout)))
+	return C.GoString(gout), gobool(gok)
+}
+
+// RemoveTag removes the values for the given tag in this list.
+func (t *TagList) RemoveTag(tag Tag) {
+	ctag := C.CString(string(tag))
+	defer C.free(unsafe.Pointer(ctag))
+	C.gst_tag_list_remove_tag(t.Instance(), (*C.gchar)(unsafe.Pointer(ctag)))
+}
+
+// SetScope sets the scope of this TagList. By default, the scope of a tag list is stream scope.
+func (t *TagList) SetScope(scope TagScope) {
+	C.gst_tag_list_set_scope(t.Instance(), C.GstTagScope(scope))
 }

gst/gst_tag_setter.go

@@ -12,9 +12,9 @@ import (
 type TagSetter interface {
 	// Returns the current list of tags the setter uses. The list should not be modified or freed.
 	GetTagList() *TagList
-	// Adds the given tag/value pair using the given merge mode.
-	// TODO: Either an additional function or this one should be modified to accept go types.
-	AddTagValue(mergeMode TagMergeMode, tagKey string, tagValue *glib.Value)
+	// Adds the given tag/value pair using the given merge mode. If the tag value cannot be coerced
+	// to a GValue when dealing with C elements, nothing will happen.
+	AddTagValue(mergeMode TagMergeMode, tagKey string, tagValue interface{})
 	// Merges a tag list with the given merge mode
 	MergeTags(*TagList, TagMergeMode)
 	// Resets the internal tag list. Elements should call this from within the state-change handler.
@@ -42,14 +42,18 @@ func (t *gstTagSetter) GetTagList() *TagList {
 	return wrapTagList(tagList)
 }
 
-func (t *gstTagSetter) AddTagValue(mergeMode TagMergeMode, tagKey string, tagValue *glib.Value) {
+func (t *gstTagSetter) AddTagValue(mergeMode TagMergeMode, tagKey string, tagValue interface{}) {
 	ckey := C.CString(tagKey)
 	defer C.free(unsafe.Pointer(ckey))
+	gVal, err := glib.GValue(tagValue)
+	if err != nil {
+		return
+	}
 	C.gst_tag_setter_add_tag_value(
 		t.Instance(),
 		C.GstTagMergeMode(mergeMode),
 		(*C.gchar)(unsafe.Pointer(ckey)),
-		(*C.GValue)(tagValue.GetPointer()),
+		(*C.GValue)(gVal.Native()),
 	)
 }
 

gst/gst_wrappers.go

@@ -2,11 +2,6 @@ package gst
 
 /*
 #include "gst.go.h"
-
-GValue * gvalPtrToGval (gpointer p)
-{
-	return (GValue*)(p);
-}
 */
 import "C"
 
@@ -134,6 +129,10 @@ func init() {
 			T: glib.Type(C.GST_TYPE_TOC),
 			F: marshalTOC,
 		},
+		{
+			T: glib.Type(C.GST_TYPE_TAG_LIST),
+			F: marsalTagList,
+		},
 
 		// Boxed
 		{T: glib.Type(C.gst_message_get_type()), F: marshalMessage},
@@ -142,7 +141,8 @@ func init() {
 }
 
 func uintptrToGVal(p uintptr) *C.GValue {
-	return (*C.GValue)(unsafe.Pointer(p))
+	return (*C.GValue)(unsafe.Pointer(p)) // vet thinks this is unsafe and there is no way around it for now.
+	// but the given ptr is an address to a C object so go's concerns are misplaced.
 }
 
 // Object wrappers
@@ -372,3 +372,9 @@ func marshalTOCEntry(p uintptr) (interface{}, error) {
 	obj := (*C.GstTocEntry)(unsafe.Pointer(c))
 	return wrapTOCEntry(obj), nil
 }
+
+func marsalTagList(p uintptr) (interface{}, error) {
+	c := C.g_value_get_object(uintptrToGVal(p))
+	obj := (*C.GstTagList)(unsafe.Pointer(c))
+	return wrapTagList(obj), nil
+}