1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
// Copyright (C) 2016-2017 Sebastian Dröge <sebastian@centricular.com>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::borrow::{Borrow, BorrowMut, ToOwned};
use std::ffi::CStr;
use std::fmt;
use std::mem;
use std::ops::{Deref, DerefMut};
use std::ptr;
use std::str;

use thiserror::Error;

use Fraction;

use glib;
use glib::translate::{
    from_glib, from_glib_full, FromGlibPtrFull, FromGlibPtrNone, GlibPtrDefault, Stash, StashMut,
    ToGlib, ToGlibPtr, ToGlibPtrMut,
};
use glib::value::{FromValue, FromValueOptional, SendValue, ToSendValue};
use glib_sys::gpointer;
use gobject_sys;
use gst_sys;

#[derive(Clone, Debug, Eq, PartialEq, Error)]
pub enum GetError<'name> {
    #[error("GetError: Structure field with name {name} not found")]
    FieldNotFound { name: &'name str },
    #[error("GetError: Structure field with name {name} not retrieved")]
    ValueGetError {
        name: &'name str,
        #[source]
        value_get_error: glib::value::GetError,
    },
}

impl<'name> GetError<'name> {
    fn new_field_not_found(name: &'name str) -> GetError {
        skip_assert_initialized!();
        GetError::FieldNotFound { name }
    }

    fn from_value_get_error(name: &'name str, value_get_error: glib::value::GetError) -> GetError {
        skip_assert_initialized!();
        GetError::ValueGetError {
            name,
            value_get_error,
        }
    }
}

/// A `Structure` is a collection of key/value pairs. The keys are expressed as
/// GQuarks and the values can be of any GType.
///
/// In addition to the key/value pairs, a `Structure` also has a name. The name
/// starts with a letter and can be filled by letters, numbers and any of
/// "/-_.:".
///
/// `Structure` is used by various GStreamer subsystems to store information in
/// a flexible and extensible way. A `Structure` does not have a refcount
/// because it usually is part of a higher level object such as `Caps`,
/// `Message`, `Event`, `Query`. It provides a means to enforce mutability
/// using the refcount of the parent with the `Structure::set_parent_refcount`
/// method.
///
/// A `Structure` can be created with `Structure::new_empty` or
/// `Structure::new`, which both take a name and an optional set of key/value
/// pairs along with the types of the values.
///
/// Field values can be changed with `Structure::set_value` or
/// `Structure::set`.
///
/// Field values can be retrieved with `Structure::get_value` or the more
/// convenient gst_structure_get_*() functions.
///
/// Fields can be removed with `Structure::remove_field` or
/// `Structure::remove_fields`.
///
/// Strings in structures must be ASCII or UTF-8 encoded. Other encodings are not
/// allowed. Strings may be `None` however.
///
/// ## The serialization format
///
/// GstStructure serialization format serialize the GstStructure name,
/// keys/GType/values in a comma separated list with the structure name as first
/// field without value followed by separated key/value pairs in the form
/// `key=value`, for example:
///
/// ```
/// a-structure, key=value
/// ````
///
/// The values type will be inferred if not explicitly specified with the
/// `(GTypeName)value` syntax, for example the following struct will have one
/// field called 'is-string' which has the string 'true' as a value:
///
/// ```
/// a-struct, field-is-string=(string)true, field-is-boolean=true
/// ```
///
/// *Note*: without specifying `(string), `field-is-string` type would have been
/// inferred as boolean.
///
/// *Note*: we specified `(string)` as a type even if `gchararray` is the actual
/// GType name as for convenience some well known types have been aliased or
/// abbreviated.
///
/// To avoid specifying the type, you can give some hints to the "type system".
/// For example to specify a value as a double, you should add a decimal (ie. `1`
/// is an `int` while `1.0` is a `double`).
///
/// *Note*: when a structure is serialized with `Structure::to_string`, all
/// values are explicitly typed.
///
/// Some types have special delimiters:
///
/// - [GstValueArray](GST_TYPE_ARRAY) are inside curly brackets (`{` and `}`).
///  For example `a-structure, array={1, 2, 3}`
/// - Ranges are inside brackets (`[` and `]`). For example `a-structure,
///   range=[1, 6, 2]` 1 being the min value, 6 the maximum and 2 the step. To
///  specify a `GST_TYPE_INT64_RANGE` you need to explicitly specify it like:
///  `a-structure, a-int64-range=(gint64) [1, 5]`
/// - [GstValueList](GST_TYPE_LIST) are inside "less and greater than" (`<` and
///  `>`). For example `a-structure, list=<1, 2, 3>
///
/// Structures are delimited either by a null character `\0` or a semicolumn `;`
/// the latter allowing to store multiple structures in the same string (see
/// #GstCaps).
///
/// Quotes are used as "default" delimiters and can be used around any types that
/// don't use other delimiters (for example `a-struct, i=(int)"1"`). They are use
/// to allow adding spaces or special characters (such as delimiters,
/// semicolumns, etc..) inside strings and you can use backslashes `\` to escape
/// characters inside them, for example:
///
/// ```
/// a-struct, special="\"{[(;)]}\" can be used inside quotes"
/// ```
///
/// They also allow for nested structure, such as:
///
/// ```
/// a-struct, nested=(GstStructure)"nested-struct, nested=true"
/// ```
///
/// > *Note*: Be aware that the current #GstCaps / #GstStructure serialization
/// > into string has limited support for nested #GstCaps / #GstStructure fields.
/// > It can only support one level of nesting. Using more levels will lead to
/// > unexpected behavior when using serialization features, such as
/// > gst_caps_to_string() or gst_value_serialize() and their counterparts.
pub struct Structure(ptr::NonNull<StructureRef>);
unsafe impl Send for Structure {}
unsafe impl Sync for Structure {}

impl Structure {
    pub fn builder(name: &str) -> Builder {
        assert_initialized_main_thread!();
        Builder::new(name)
    }

    /// Creates a new, empty `Structure` with the given `name`.
    ///
    /// See `Structure::set_name` for constraints on the `name` parameter.
    ///
    /// Free-function: gst_structure_free
    /// ## `name`
    /// name of new structure
    ///
    /// # Returns
    ///
    /// a new, empty `Structure`
    pub fn new_empty(name: &str) -> Structure {
        assert_initialized_main_thread!();
        unsafe {
            let ptr = gst_sys::gst_structure_new_empty(name.to_glib_none().0) as *mut StructureRef;
            assert!(!ptr.is_null());
            Structure(ptr::NonNull::new_unchecked(ptr))
        }
    }

    /// Creates a new `Structure` with the given name. Parses the
    /// list of variable arguments and sets fields to the values listed.
    /// Variable arguments should be passed as field name, field type,
    /// and value. Last variable argument should be `None`.
    ///
    /// Free-function: gst_structure_free
    /// ## `name`
    /// name of new structure
    /// ## `firstfield`
    /// name of first field to set
    ///
    /// # Returns
    ///
    /// a new `Structure`
    pub fn new(name: &str, values: &[(&str, &dyn ToSendValue)]) -> Structure {
        assert_initialized_main_thread!();
        let mut structure = Structure::new_empty(name);

        for &(f, v) in values {
            structure.set_value(f, v.to_send_value());
        }

        structure
    }

    pub unsafe fn into_ptr(self) -> *mut gst_sys::GstStructure {
        let s = mem::ManuallyDrop::new(self);
        s.0.as_ptr() as *mut StructureRef as *mut gst_sys::GstStructure
    }

    #[allow(clippy::should_implement_trait)]
    pub fn from_iter<'a, 'b, I>(name: &str, iter: I) -> Structure
    where
        I: IntoIterator<Item = (&'a str, &'b SendValue)>,
    {
        assert_initialized_main_thread!();
        let mut structure = Structure::new_empty(name);

        iter.into_iter().for_each(|(f, v)| unsafe {
            let mut value = v.clone().into_raw();
            gst_sys::gst_structure_take_value(
                &mut structure.0.as_mut().0,
                f.to_glib_none().0,
                &mut value,
            );
        });

        structure
    }
}

impl Deref for Structure {
    type Target = StructureRef;

    fn deref(&self) -> &StructureRef {
        unsafe { self.0.as_ref() }
    }
}

impl DerefMut for Structure {
    fn deref_mut(&mut self) -> &mut StructureRef {
        unsafe { self.0.as_mut() }
    }
}

impl AsRef<StructureRef> for Structure {
    fn as_ref(&self) -> &StructureRef {
        self.deref()
    }
}

impl AsMut<StructureRef> for Structure {
    fn as_mut(&mut self) -> &mut StructureRef {
        self.deref_mut()
    }
}

impl Clone for Structure {
    fn clone(&self) -> Self {
        unsafe {
            let ptr = gst_sys::gst_structure_copy(&self.0.as_ref().0) as *mut StructureRef;
            assert!(!ptr.is_null());
            Structure(ptr::NonNull::new_unchecked(ptr))
        }
    }
}

impl Drop for Structure {
    fn drop(&mut self) {
        unsafe { gst_sys::gst_structure_free(&mut self.0.as_mut().0) }
    }
}

impl fmt::Debug for Structure {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.debug_tuple("Structure").field(&self.to_string()).finish()
    }
}

impl fmt::Display for Structure {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        // Need to make sure to not call ToString::to_string() here, which
        // we have because of the Display impl. We need StructureRef::to_string()
        f.write_str(&StructureRef::to_string(self.as_ref()))
    }
}

impl PartialEq for Structure {
    fn eq(&self, other: &Structure) -> bool {
        self.as_ref().eq(other)
    }
}

impl PartialEq<StructureRef> for Structure {
    fn eq(&self, other: &StructureRef) -> bool {
        self.as_ref().eq(other)
    }
}

impl Eq for Structure {}

impl str::FromStr for Structure {
    type Err = glib::BoolError;

    fn from_str(s: &str) -> Result<Self, glib::BoolError> {
        assert_initialized_main_thread!();
        unsafe {
            let structure = gst_sys::gst_structure_from_string(s.to_glib_none().0, ptr::null_mut());
            if structure.is_null() {
                Err(glib_bool_error!("Failed to parse structure from string"))
            } else {
                Ok(Structure(ptr::NonNull::new_unchecked(
                    structure as *mut StructureRef,
                )))
            }
        }
    }
}

impl Borrow<StructureRef> for Structure {
    fn borrow(&self) -> &StructureRef {
        unsafe { self.0.as_ref() }
    }
}

impl BorrowMut<StructureRef> for Structure {
    fn borrow_mut(&mut self) -> &mut StructureRef {
        unsafe { self.0.as_mut() }
    }
}

impl ToOwned for StructureRef {
    type Owned = Structure;

    fn to_owned(&self) -> Structure {
        unsafe {
            let ptr = gst_sys::gst_structure_copy(&self.0) as *mut StructureRef;
            assert!(!ptr.is_null());
            Structure(ptr::NonNull::new_unchecked(ptr))
        }
    }
}

impl glib::types::StaticType for Structure {
    fn static_type() -> glib::types::Type {
        unsafe { from_glib(gst_sys::gst_structure_get_type()) }
    }
}

impl<'a> ToGlibPtr<'a, *const gst_sys::GstStructure> for Structure {
    type Storage = &'a Self;

    fn to_glib_none(&'a self) -> Stash<'a, *const gst_sys::GstStructure, Self> {
        unsafe { Stash(&self.0.as_ref().0, self) }
    }

    fn to_glib_full(&self) -> *const gst_sys::GstStructure {
        unsafe { gst_sys::gst_structure_copy(&self.0.as_ref().0) }
    }
}

impl<'a> ToGlibPtr<'a, *mut gst_sys::GstStructure> for Structure {
    type Storage = &'a Self;

    fn to_glib_none(&'a self) -> Stash<'a, *mut gst_sys::GstStructure, Self> {
        unsafe { Stash(&self.0.as_ref().0 as *const _ as *mut _, self) }
    }

    fn to_glib_full(&self) -> *mut gst_sys::GstStructure {
        unsafe { gst_sys::gst_structure_copy(&self.0.as_ref().0) }
    }
}

impl<'a> ToGlibPtrMut<'a, *mut gst_sys::GstStructure> for Structure {
    type Storage = &'a mut Self;

    fn to_glib_none_mut(&'a mut self) -> StashMut<*mut gst_sys::GstStructure, Self> {
        unsafe { StashMut(&mut self.0.as_mut().0, self) }
    }
}

impl FromGlibPtrNone<*const gst_sys::GstStructure> for Structure {
    unsafe fn from_glib_none(ptr: *const gst_sys::GstStructure) -> Self {
        assert!(!ptr.is_null());
        let ptr = gst_sys::gst_structure_copy(ptr);
        assert!(!ptr.is_null());
        Structure(ptr::NonNull::new_unchecked(ptr as *mut StructureRef))
    }
}

impl FromGlibPtrNone<*mut gst_sys::GstStructure> for Structure {
    unsafe fn from_glib_none(ptr: *mut gst_sys::GstStructure) -> Self {
        assert!(!ptr.is_null());
        let ptr = gst_sys::gst_structure_copy(ptr);
        assert!(!ptr.is_null());
        Structure(ptr::NonNull::new_unchecked(ptr as *mut StructureRef))
    }
}

impl FromGlibPtrFull<*const gst_sys::GstStructure> for Structure {
    unsafe fn from_glib_full(ptr: *const gst_sys::GstStructure) -> Self {
        assert!(!ptr.is_null());
        Structure(ptr::NonNull::new_unchecked(ptr as *mut StructureRef))
    }
}

impl FromGlibPtrFull<*mut gst_sys::GstStructure> for Structure {
    unsafe fn from_glib_full(ptr: *mut gst_sys::GstStructure) -> Self {
        assert!(!ptr.is_null());
        Structure(ptr::NonNull::new_unchecked(ptr as *mut StructureRef))
    }
}

impl<'a> glib::value::FromValueOptional<'a> for Structure {
    unsafe fn from_value_optional(v: &'a glib::Value) -> Option<Self> {
        <&'a StructureRef as glib::value::FromValueOptional<'a>>::from_value_optional(v)
            .map(ToOwned::to_owned)
    }
}

impl glib::value::SetValue for Structure {
    unsafe fn set_value(v: &mut glib::Value, s: &Self) {
        <StructureRef as glib::value::SetValue>::set_value(v, s.as_ref())
    }
}

impl glib::value::SetValueOptional for Structure {
    unsafe fn set_value_optional(v: &mut glib::Value, s: Option<&Self>) {
        <StructureRef as glib::value::SetValueOptional>::set_value_optional(
            v,
            s.map(|s| s.as_ref()),
        )
    }
}

impl GlibPtrDefault for Structure {
    type GlibType = *mut gst_sys::GstStructure;
}

#[repr(transparent)]
pub struct StructureRef(gst_sys::GstStructure);

unsafe impl Send for StructureRef {}
unsafe impl Sync for StructureRef {}

impl StructureRef {
    pub unsafe fn from_glib_borrow<'a>(ptr: *const gst_sys::GstStructure) -> &'a StructureRef {
        assert!(!ptr.is_null());

        &*(ptr as *mut StructureRef)
    }

    pub unsafe fn from_glib_borrow_mut<'a>(
        ptr: *mut gst_sys::GstStructure,
    ) -> &'a mut StructureRef {
        assert!(!ptr.is_null());

        &mut *(ptr as *mut StructureRef)
    }

    pub unsafe fn as_ptr(&self) -> *const gst_sys::GstStructure {
        self as *const Self as *const gst_sys::GstStructure
    }

    pub unsafe fn as_mut_ptr(&self) -> *mut gst_sys::GstStructure {
        self as *const Self as *mut gst_sys::GstStructure
    }

    pub fn get<'structure, 'name, T: FromValueOptional<'structure>>(
        &'structure self,
        name: &'name str,
    ) -> Result<Option<T>, GetError<'name>> {
        self.get_value(name)?
            .get()
            .map_err(|err| GetError::from_value_get_error(name, err))
    }

    pub fn get_optional<'structure, 'name, T: FromValueOptional<'structure>>(
        &'structure self,
        name: &'name str,
    ) -> Result<Option<T>, GetError<'name>> {
        let value = self.get_value(name);
        if let Ok(value) = value {
            value
                .get()
                .map_err(|err| GetError::from_value_get_error(name, err))
        } else {
            Ok(None)
        }
    }

    pub fn get_some<'structure, 'name, T: FromValue<'structure>>(
        &'structure self,
        name: &'name str,
    ) -> Result<T, GetError<'name>> {
        self.get_value(name)?
            .get_some()
            .map_err(|err| GetError::from_value_get_error(name, err))
    }

    pub fn get_value<'structure, 'name>(
        &'structure self,
        name: &'name str,
    ) -> Result<&SendValue, GetError<'name>> {
        unsafe {
            let value = gst_sys::gst_structure_get_value(&self.0, name.to_glib_none().0);

            if value.is_null() {
                return Err(GetError::new_field_not_found(name));
            }

            Ok(&*(value as *const SendValue))
        }
    }

    pub fn set<T: ToSendValue>(&mut self, name: &str, value: &T) {
        let value = value.to_send_value();
        self.set_value(name, value);
    }

    pub fn set_value(&mut self, name: &str, value: SendValue) {
        unsafe {
            let mut value = value.into_raw();
            gst_sys::gst_structure_take_value(&mut self.0, name.to_glib_none().0, &mut value);
        }
    }

    pub fn get_name<'a>(&self) -> &'a str {
        unsafe {
            CStr::from_ptr(gst_sys::gst_structure_get_name(&self.0))
                .to_str()
                .unwrap()
        }
    }

    pub fn set_name(&mut self, name: &str) {
        unsafe { gst_sys::gst_structure_set_name(&mut self.0, name.to_glib_none().0) }
    }

    pub fn has_field(&self, field: &str) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_has_field(
                &self.0,
                field.to_glib_none().0,
            ))
        }
    }

    pub fn has_field_with_type(&self, field: &str, type_: glib::Type) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_has_field_typed(
                &self.0,
                field.to_glib_none().0,
                type_.to_glib(),
            ))
        }
    }

    pub fn remove_field(&mut self, field: &str) {
        unsafe {
            gst_sys::gst_structure_remove_field(&mut self.0, field.to_glib_none().0);
        }
    }

    pub fn remove_fields(&mut self, fields: &[&str]) {
        for f in fields {
            self.remove_field(f)
        }
    }

    pub fn remove_all_fields(&mut self) {
        unsafe {
            gst_sys::gst_structure_remove_all_fields(&mut self.0);
        }
    }

    pub fn fields(&self) -> FieldIterator {
        FieldIterator::new(self)
    }

    pub fn iter(&self) -> Iter {
        Iter::new(self)
    }

    pub fn get_nth_field_name<'a>(&self, idx: u32) -> Option<&'a str> {
        unsafe {
            let field_name = gst_sys::gst_structure_nth_field_name(&self.0, idx);
            if field_name.is_null() {
                return None;
            }

            Some(CStr::from_ptr(field_name).to_str().unwrap())
        }
    }

    pub fn n_fields(&self) -> u32 {
        unsafe { gst_sys::gst_structure_n_fields(&self.0) as u32 }
    }

    pub fn can_intersect(&self, other: &StructureRef) -> bool {
        unsafe { from_glib(gst_sys::gst_structure_can_intersect(&self.0, &other.0)) }
    }

    pub fn intersect(&self, other: &StructureRef) -> Option<Structure> {
        unsafe { from_glib_full(gst_sys::gst_structure_intersect(&self.0, &other.0)) }
    }

    pub fn is_subset(&self, superset: &StructureRef) -> bool {
        unsafe { from_glib(gst_sys::gst_structure_is_subset(&self.0, &superset.0)) }
    }

    pub fn fixate(&mut self) {
        unsafe { gst_sys::gst_structure_fixate(&mut self.0) }
    }

    pub fn fixate_field(&mut self, name: &str) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_fixate_field(
                &mut self.0,
                name.to_glib_none().0,
            ))
        }
    }

    pub fn fixate_field_bool(&mut self, name: &str, target: bool) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_fixate_field_boolean(
                &mut self.0,
                name.to_glib_none().0,
                target.to_glib(),
            ))
        }
    }

    pub fn fixate_field_str(&mut self, name: &str, target: &str) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_fixate_field_string(
                &mut self.0,
                name.to_glib_none().0,
                target.to_glib_none().0,
            ))
        }
    }

    pub fn fixate_field_nearest_double(&mut self, name: &str, target: f64) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_fixate_field_nearest_double(
                &mut self.0,
                name.to_glib_none().0,
                target,
            ))
        }
    }

    pub fn fixate_field_nearest_fraction<T: Into<Fraction>>(
        &mut self,
        name: &str,
        target: T,
    ) -> bool {
        skip_assert_initialized!();

        let target = target.into();
        unsafe {
            from_glib(gst_sys::gst_structure_fixate_field_nearest_fraction(
                &mut self.0,
                name.to_glib_none().0,
                *target.numer(),
                *target.denom(),
            ))
        }
    }

    pub fn fixate_field_nearest_int(&mut self, name: &str, target: i32) -> bool {
        unsafe {
            from_glib(gst_sys::gst_structure_fixate_field_nearest_int(
                &mut self.0,
                name.to_glib_none().0,
                target,
            ))
        }
    }
}

impl fmt::Display for StructureRef {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let s = unsafe { glib::GString::from_glib_full(gst_sys::gst_structure_to_string(&self.0)) };
        f.write_str(&s)
    }
}

impl fmt::Debug for StructureRef {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(&self.to_string())
    }
}

impl PartialEq for StructureRef {
    fn eq(&self, other: &StructureRef) -> bool {
        unsafe { from_glib(gst_sys::gst_structure_is_equal(&self.0, &other.0)) }
    }
}

impl Eq for StructureRef {}

impl glib::types::StaticType for StructureRef {
    fn static_type() -> glib::types::Type {
        unsafe { from_glib(gst_sys::gst_structure_get_type()) }
    }
}

impl<'a> glib::value::FromValueOptional<'a> for &'a StructureRef {
    unsafe fn from_value_optional(v: &'a glib::Value) -> Option<Self> {
        let ptr = gobject_sys::g_value_get_boxed(v.to_glib_none().0);
        if ptr.is_null() {
            None
        } else {
            Some(StructureRef::from_glib_borrow(
                ptr as *const gst_sys::GstStructure,
            ))
        }
    }
}

impl glib::value::SetValue for StructureRef {
    unsafe fn set_value(v: &mut glib::Value, s: &Self) {
        gobject_sys::g_value_set_boxed(v.to_glib_none_mut().0, s.as_ptr() as gpointer);
    }
}

impl glib::value::SetValueOptional for StructureRef {
    unsafe fn set_value_optional(v: &mut glib::Value, s: Option<&Self>) {
        if let Some(s) = s {
            gobject_sys::g_value_set_boxed(v.to_glib_none_mut().0, s.as_ptr() as gpointer);
        } else {
            gobject_sys::g_value_set_boxed(v.to_glib_none_mut().0, ptr::null_mut());
        }
    }
}

#[derive(Debug)]
pub struct FieldIterator<'a> {
    structure: &'a StructureRef,
    idx: u32,
    n_fields: u32,
}

impl<'a> FieldIterator<'a> {
    fn new(structure: &'a StructureRef) -> FieldIterator<'a> {
        skip_assert_initialized!();
        let n_fields = structure.n_fields();

        FieldIterator {
            structure,
            idx: 0,
            n_fields,
        }
    }
}

impl<'a> Iterator for FieldIterator<'a> {
    type Item = &'static str;

    fn next(&mut self) -> Option<Self::Item> {
        if self.idx >= self.n_fields {
            return None;
        }

        if let Some(field_name) = self.structure.get_nth_field_name(self.idx) {
            self.idx += 1;
            Some(field_name)
        } else {
            None
        }
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        if self.idx == self.n_fields {
            return (0, Some(0));
        }

        let remaining = (self.n_fields - self.idx) as usize;

        (remaining, Some(remaining))
    }
}

impl<'a> DoubleEndedIterator for FieldIterator<'a> {
    fn next_back(&mut self) -> Option<Self::Item> {
        if self.idx == self.n_fields {
            return None;
        }

        self.n_fields -= 1;
        if let Some(field_name) = self.structure.get_nth_field_name(self.n_fields) {
            Some(field_name)
        } else {
            None
        }
    }
}

impl<'a> ExactSizeIterator for FieldIterator<'a> {}

#[derive(Debug)]
pub struct Iter<'a> {
    iter: FieldIterator<'a>,
}

impl<'a> Iter<'a> {
    fn new(structure: &'a StructureRef) -> Iter<'a> {
        skip_assert_initialized!();
        Iter {
            iter: FieldIterator::new(structure),
        }
    }
}

impl<'a> Iterator for Iter<'a> {
    type Item = (&'static str, &'a SendValue);

    fn next(&mut self) -> Option<Self::Item> {
        if let Some(f) = self.iter.next() {
            let v = self.iter.structure.get_value(f);
            Some((f, v.unwrap()))
        } else {
            None
        }
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        self.iter.size_hint()
    }
}

impl<'a> DoubleEndedIterator for Iter<'a> {
    fn next_back(&mut self) -> Option<Self::Item> {
        if let Some(f) = self.iter.next_back() {
            let v = self.iter.structure.get_value(f);
            Some((f, v.unwrap()))
        } else {
            None
        }
    }
}

impl<'a> ExactSizeIterator for Iter<'a> {}

#[derive(Debug)]
pub struct Builder {
    s: Structure,
}

impl Builder {
    fn new(name: &str) -> Self {
        skip_assert_initialized!();
        Builder {
            s: Structure::new_empty(name),
        }
    }

    pub fn field<V: ToSendValue>(mut self, name: &str, value: &V) -> Self {
        self.s.set(name, value);
        self
    }

    pub fn build(self) -> Structure {
        self.s
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::str::FromStr;

    #[test]
    fn new_set_get() {
        use glib::{value, Type};

        ::init().unwrap();

        let mut s = Structure::new_empty("test");
        assert_eq!(s.get_name(), "test");

        s.set("f1", &"abc");
        s.set("f2", &String::from("bcd"));
        s.set("f3", &123i32);

        assert_eq!(s.get::<&str>("f1"), Ok(Some("abc")));
        assert_eq!(s.get::<&str>("f2"), Ok(Some("bcd")));
        assert_eq!(s.get_some::<i32>("f3"), Ok(123i32));
        assert_eq!(s.get_optional::<&str>("f1"), Ok(Some("abc")));
        assert_eq!(s.get_optional::<&str>("f4"), Ok(None));
        assert_eq!(s.get_optional::<i32>("f3"), Ok(Some(123i32)));
        assert_eq!(s.get_optional::<i32>("f4"), Ok(None));

        assert_eq!(
            s.get::<i32>("f2"),
            Err(GetError::from_value_get_error(
                "f2",
                value::GetError::new_type_mismatch(Type::String, Type::I32),
            ))
        );
        assert_eq!(
            s.get_some::<bool>("f3"),
            Err(GetError::from_value_get_error(
                "f3",
                value::GetError::new_type_mismatch(Type::I32, Type::Bool),
            ))
        );
        assert_eq!(
            s.get::<&str>("f4"),
            Err(GetError::new_field_not_found("f4"))
        );
        assert_eq!(
            s.get_some::<i32>("f4"),
            Err(GetError::new_field_not_found("f4"))
        );

        assert_eq!(s.fields().collect::<Vec<_>>(), vec!["f1", "f2", "f3"]);

        let v = s.iter().map(|(f, v)| (f, v.clone())).collect::<Vec<_>>();
        assert_eq!(v.len(), 3);
        assert_eq!(v[0].0, "f1");
        assert_eq!(v[0].1.get::<&str>(), Ok(Some("abc")));
        assert_eq!(v[1].0, "f2");
        assert_eq!(v[1].1.get::<&str>(), Ok(Some("bcd")));
        assert_eq!(v[2].0, "f3");
        assert_eq!(v[2].1.get_some::<i32>(), Ok(123i32));

        let s2 = Structure::new("test", &[("f1", &"abc"), ("f2", &"bcd"), ("f3", &123i32)]);
        assert_eq!(s, s2);
    }

    #[test]
    fn test_builder() {
        ::init().unwrap();

        let s = Structure::builder("test")
            .field("f1", &"abc")
            .field("f2", &String::from("bcd"))
            .field("f3", &123i32)
            .build();

        assert_eq!(s.get_name(), "test");
        assert_eq!(s.get::<&str>("f1"), Ok(Some("abc")));
        assert_eq!(s.get::<&str>("f2"), Ok(Some("bcd")));
        assert_eq!(s.get_some::<i32>("f3"), Ok(123i32));
    }

    #[test]
    fn test_string_conversion() {
        ::init().unwrap();

        let a = "Test, f1=(string)abc, f2=(uint)123;";

        let s = Structure::from_str(&a).unwrap();
        assert_eq!(s.get::<&str>("f1"), Ok(Some("abc")));
        assert_eq!(s.get_some::<u32>("f2"), Ok(123));

        assert_eq!(a, s.to_string());
    }

    #[test]
    fn test_from_value_optional() {
        ::init().unwrap();

        let a = glib::value::Value::from(None::<&Structure>);
        assert!(a.get::<Structure>().unwrap().is_none());
        let b = glib::value::Value::from(&Structure::from_str(&"foo").unwrap());
        assert!(b.get::<Structure>().unwrap().is_some());
    }

    #[test]
    fn test_new_from_iter() {
        ::init().unwrap();

        let s = Structure::builder("test")
            .field("f1", &"abc")
            .field("f2", &String::from("bcd"))
            .field("f3", &123i32)
            .build();

        let s2 = Structure::from_iter(s.get_name(), s.iter().filter(|(f, _)| *f == "f1"));

        assert_eq!(s2.get_name(), "test");
        assert_eq!(s2.get::<&str>("f1"), Ok(Some("abc")));
        assert!(s2.get::<&str>("f2").is_err());
        assert!(s2.get::<&str>("f3").is_err());
    }
}