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
// Copyright 2013-2016, The Gtk-rs Project Developers.
// See the COPYRIGHT file at the top-level directory of this distribution.
// Licensed under the MIT license, see the LICENSE file or <http://opensource.org/licenses/MIT>

//! `Variant` binding and helper traits.
//!
//! [`Variant`](struct.Variant.html) is an immutable dynamically-typed generic
//! container. Its type and value are defined at construction and never change.
//!
//! `Variant` types are described by [`VariantType`](../struct.VariantType.html)
//! "type strings".
//!
//! Although `GVariant` supports arbitrarily complex types, this binding is
//! currently limited to the basic ones: `bool`, `u8`, `i16`, `u16`, `i32`,
//! `u32`, `i64`, `u64`, `f64` and `&str`/`String`.
//!
//! # Examples
//!
//! ```
//! use glib::prelude::*; // or `use gtk::prelude::*;`
//! use glib::Variant;
//!
//! // Using the `ToVariant` trait.
//! let num = 10.to_variant();
//!
//! // `is` tests the type of the value.
//! assert!(num.is::<i32>());
//!
//! // `get` tries to extract the value.
//! assert_eq!(num.get::<i32>(), Some(10));
//! assert_eq!(num.get::<u32>(), None);
//!
//! // `Variant` implements `From`
//! let hello = Variant::from("Hello!");
//!
//! // `get_str` tries to borrow a string slice.
//! assert_eq!(hello.get_str(), Some("Hello!"));
//! assert_eq!(num.get_str(), None);
//! ```

use VariantTy;
use ffi as glib_ffi;
use translate::*;
use std::borrow::Cow;
use std::cmp::{PartialEq, Eq};
use std::fmt;
use std::hash::{Hash, Hasher};
use std::slice;
use std::str;

glib_wrapper! {
    /// A generic immutable value capable of carrying various types.
    ///
    /// See the [module documentation](index.html) for more details.
    pub struct Variant(Shared<glib_ffi::GVariant>);

    match fn {
        ref => |ptr| glib_ffi::g_variant_ref_sink(ptr),
        unref => |ptr| glib_ffi::g_variant_unref(ptr),
    }
}

impl Variant {
    /// Returns the type of the value.
    pub fn type_(&self) -> &VariantTy {
        unsafe { VariantTy::from_ptr(glib_ffi::g_variant_get_type(self.to_glib_none().0)) }
    }

    /// Returns `true` if the type of the value corresponds to `T`.
    #[inline]
    pub fn is<T: StaticVariantType>(&self) -> bool {
        self.type_() == T::static_variant_type()
    }

    /// Tries to extract a value of type `T`.
    ///
    /// Returns `Some` if `T` matches the variant's type.
    #[inline]
    pub fn get<T: FromVariant>(&self) -> Option<T> {
        T::from_variant(self)
    }

    /// Tries to extract a `&str`.
    ///
    /// Returns `Some` if the variant has a string type (`s`, `o` or `g` type
    /// strings).
    pub fn get_str(&self) -> Option<&str> {
        unsafe {
            match self.type_().to_str() {
                "s" | "o" | "g" => {
                    let mut len = 0;
                    let ptr = glib_ffi::g_variant_get_string(self.to_glib_none().0, &mut len);
                    let ret = str::from_utf8_unchecked(
                        slice::from_raw_parts(ptr as *const u8, len as usize));
                    Some(ret)
                }
                _ => None,
            }
        }
    }
}

unsafe impl Send for Variant { }
unsafe impl Sync for Variant { }

impl fmt::Debug for Variant {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_fmt(format_args!("Variant {{ ptr: {:?}, type: \"{}\", value: {} }}",
            self.to_glib_none().0, self.type_(), self))
    }
}

impl fmt::Display for Variant {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let serialized: String = unsafe {
            from_glib_full(glib_ffi::g_variant_print(self.to_glib_none().0, false.to_glib()))
        };
        f.write_str(&serialized)
    }
}

impl PartialEq for Variant {
    fn eq(&self, other: &Self) -> bool {
        unsafe {
            from_glib(
                glib_ffi::g_variant_equal(self.to_glib_none().0 as *const _,
                    other.to_glib_none().0 as *const _))
        }
    }
}

impl Eq for Variant { }

impl Hash for Variant {
    fn hash<H: Hasher>(&self, state: &mut H) {
        unsafe {
            state.write_u32(glib_ffi::g_variant_hash(self.to_glib_none().0 as *const _))
        }
    }
}

/// Converts to `Variant`.
pub trait ToVariant {
    /// Returns a `Variant` clone of `self`.
    fn to_variant(&self) -> Variant;
}

/// Extracts a value.
pub trait FromVariant: Sized + StaticVariantType {
    /// Tries to extract a value.
    ///
    /// Returns `Some` if the variant's type matches `Self`.
    fn from_variant(variant: &Variant) -> Option<Self>;
}

/// Returns `VariantType` of `Self`.
pub trait StaticVariantType {
    /// Returns the `VariantType` corresponding to `Self`.
    fn static_variant_type() -> Cow<'static, VariantTy>;
}

impl<'a, T: ?Sized + ToVariant> ToVariant for &'a T {
    fn to_variant(&self) -> Variant {
        <T as ToVariant>::to_variant(self)
    }
}

impl<'a, T: ?Sized + StaticVariantType> StaticVariantType for &'a T {
    fn static_variant_type() -> Cow<'static, VariantTy> {
        <T as StaticVariantType>::static_variant_type()
    }
}

macro_rules! impl_numeric {
    ($name:ty, $type_str:expr, $new_fn:ident, $get_fn:ident) => {
        impl StaticVariantType for $name {
            fn static_variant_type() -> Cow<'static, VariantTy> {
                unsafe { VariantTy::from_str_unchecked($type_str).into() }
            }
        }

        impl ToVariant for $name {
            fn to_variant(&self) -> Variant {
                unsafe { from_glib_none(glib_ffi::$new_fn(*self)) }
            }
        }

        impl FromVariant for $name {
            fn from_variant(variant: &Variant) -> Option<Self> {
                unsafe {
                    if variant.is::<Self>() {
                        Some(glib_ffi::$get_fn(variant.to_glib_none().0))
                    } else {
                        None
                    }
                }
            }
        }
    }
}

impl_numeric!(u8, "y", g_variant_new_byte, g_variant_get_byte);
impl_numeric!(i16, "n", g_variant_new_int16, g_variant_get_int16);
impl_numeric!(u16, "q", g_variant_new_uint16, g_variant_get_uint16);
impl_numeric!(i32, "i", g_variant_new_int32, g_variant_get_int32);
impl_numeric!(u32, "u", g_variant_new_uint32, g_variant_get_uint32);
impl_numeric!(i64, "x", g_variant_new_int64, g_variant_get_int64);
impl_numeric!(u64, "t", g_variant_new_uint64, g_variant_get_uint64);
impl_numeric!(f64, "d", g_variant_new_double, g_variant_get_double);

impl StaticVariantType for bool {
    fn static_variant_type() -> Cow<'static, VariantTy> {
        unsafe { VariantTy::from_str_unchecked("b").into() }
    }
}

impl ToVariant for bool {
    fn to_variant(&self) -> Variant {
        unsafe { from_glib_none(glib_ffi::g_variant_new_boolean(self.to_glib())) }
    }
}

impl FromVariant for bool {
    fn from_variant(variant: &Variant) -> Option<Self> {
        unsafe {
            if variant.is::<Self>() {
                Some(from_glib(glib_ffi::g_variant_get_boolean(variant.to_glib_none().0)))
            } else {
                None
            }
        }
    }
}

impl StaticVariantType for String {
    fn static_variant_type() -> Cow<'static, VariantTy> {
        unsafe { VariantTy::from_str_unchecked("s").into() }
    }
}

impl ToVariant for String {
    fn to_variant(&self) -> Variant {
        self[..].to_variant()
    }
}

impl FromVariant for String {
    fn from_variant(variant: &Variant) -> Option<Self> {
        variant.get_str().map(String::from)
    }
}

impl StaticVariantType for str {
    fn static_variant_type() -> Cow<'static, VariantTy> {
        unsafe { VariantTy::from_str_unchecked("s").into() }
    }
}

impl ToVariant for str {
    #[cfg(feature = "v2_38")]
    fn to_variant(&self) -> Variant {
        unsafe { from_glib_none(glib_ffi::g_variant_new_take_string(self.to_glib_full())) }
    }

    #[cfg(not(feature = "v2_38"))]
    fn to_variant(&self) -> Variant {
        unsafe { from_glib_none(glib_ffi::g_variant_new_string(self.to_glib_none().0)) }
    }
}

impl<T: ToVariant> From<T> for Variant {
    fn from(value: T) -> Variant {
        value.to_variant()
    }
}

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

    macro_rules! unsigned {
        ($name:ident, $ty:ident) => {
            #[test]
            fn $name() {
                let mut n = $ty::max_value();
                while n > 0  {
                    let v = Variant::from(n);
                    assert_eq!(v.get(), Some(n));
                    n /= 2;
                }
            }
        }
    }

    macro_rules! signed {
        ($name:ident, $ty:ident) => {
            #[test]
            fn $name() {
                let mut n = $ty::max_value();
                while n > 0  {
                    let v = Variant::from(n);
                    assert_eq!(v.get(), Some(n));
                    let v = Variant::from(-n);
                    assert_eq!(v.get(), Some(-n));
                    n /= 2;
                }
            }
        }
    }

    unsigned!(test_u8, u8);
    unsigned!(test_u16, u16);
    unsigned!(test_u32, u32);
    unsigned!(test_u64, u64);
    signed!(test_i16, i16);
    signed!(test_i32, i32);
    signed!(test_i64, i64);

    #[test]
    fn test_str() {
        let s = "this is a test";
        let v = Variant::from(s);
        assert_eq!(v.get_str(), Some(s));
    }

    #[test]
    fn test_string() {
        let s = String::from("this is a test");
        let v = Variant::from(s.clone());
        assert_eq!(v.get(), Some(s.clone()));
    }

    #[test]
    fn test_eq() {
        let v1 = Variant::from("this is a test");
        let v2 = Variant::from("this is a test");
        let v3 = Variant::from("test");
        assert_eq!(v1, v2);
        assert!(v1 != v3);
    }

    #[test]
    fn test_hash() {
        let v1 = Variant::from("this is a test");
        let v2 = Variant::from("this is a test");
        let v3 = Variant::from("test");
        let mut set = HashSet::new();
        set.insert(v1);
        assert!(set.contains(&v2));
        assert!(!set.contains(&v3));
    }
}